Note: Descriptions are shown in the official language in which they were submitted.
CA 02583519 2007-04-20
METHOD AND SYSTEM FOR MINING HYDROCARBON-CONTAINING
MATERIALS
FIELD OF THE INVENTION
The present invention is related to the mining and/or processing of soft-ore
deposits generally and to the mining and/or processing of bitumen-containing
materials,
such as oil sands, specifically.
BACKGROUND OF THE INVENTION
Oil is a nonrenewable natural resource having great importance to the
industrialized world. Over the last century, the consumption of oil has
increased
dramatically and has become a strategic commodity, leading to the development
of
alternative sources of crude oil such as oil sands and oil shales. As used
herein, oil sands
are a granular or particulate material, such as an interlocked skeleton of
sand, with pore
spaces occupied by bitumen (an amorphous solid hydrocarbon material totally
soluble in
carbon disulfide), and oil shale is a rock containing kerogen (a carbonaceous
material
that which gives rise to crude oil on distillation). The vast majority of the
world's oil
sands deposits are found in Canada and Venezuela. Collectively, oil sands
deposits
contain an estimated 10 trillion barrels of in-place oil. Oil shales are found
worldwide
with large deposits in the U.S. Collectively, oil shale deposits contain an
estimated 30
trillion barrels or more of in-place oil. It is to be understood that a
reference to oil sands
is intended to include oil shales and vice versa.
Bitumen is typically an asphalt-like substance having an API gravity commonly
ranging from about 5 to about 10 and is contained within the pore space of
the oil
sands. Bitumen cannot be recovered by traditional oil well technology because
it will not
flow at ambient reservoir temperatures. To overcome this limitation, near
surface oil
sand deposits are excavated by surface mining methods, while bitumen in deeper
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deposits is recovered by in situ techniques, which rely on steam or diluents
to mobilize
the bitumen so that it can be pumped out by conventional oil recovery methods.
The
bitumen is recovered from the surface excavated oil sands by known separation
methods,
and the bitumen, whether derived from surface mining or in situ processes,
sent to
upgrading facilities where it is converted into crude oil and other petroleum
products.
Underground mining techniques have been largely unsuccessful in mining deeper
oil
sands due to high mining costs and unstable overburden conditions.
Existing methods for recovering oil from oil sands have numerous drawbacks.
Surface mining techniques are typically only economical for shallow oil sands
deposits.
It is common for oil sands deposits to dip and a significant part of the ore
body may be
located at depths that are too deep to recover by surface mining methods. As a
result,
most of the oil sands deposits are unprofitable to mine. Surface mining
requires large
areas to be stripped of overburden which then must be moved to other areas for
storage.
The tailings from the bitumen separation process typically require large
tailings ponds
complexes in which the tailings are treated before the mined land can be
reclaimed. The
costs of stripping overburden, building and maintaining tailings ponds and
eventual land
reclamation costs can be high, particularly for deeper oil sands deposits.
Because of the
large scale of these operations, the short and long term environmental impact
and
associated costs of surface mining can be substantial. In situ techniques are
disadvantaged in that a relatively large amount of energy is consumed per unit
energy
recovered in the bitumen.
A significant portion of oil sands deposits lie too deep for economical
recovery
by surface mining and are too shallow for effective in-situ recovery. Other
oil sands
deposits, though located at shallow depths, are located under surface features
that
preclude the use of surface mining. For example, oil sands deposits can be
located under
lakes, swamps, protected animal habitats and surface mine facilities such as
tailings
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ponds. Estimates for economical grade bitumen in these in-between and
inaccessible
areas range from 30 to 100 billion barrels.
SUMMARY OF THE INVENTION
These and other needs are addressed by one or more of the various inventions
discussed herein. Certain of the inventions relate to excavating materials,
particularly
soft-ore or sedimentary materials, by underground mining techniques. The
material
excavated by these methods can be any valuable material, particularly in-situ
or in-place
hydrocarbon-containing materials, such as found in oil sands, oil shales,
conventional oil
reservoirs, coal deposits and the like, as well as other valuable minerals
such as bauxite,
potash, trona and the like.
In a first embodiment, the present invention provides an underground mining
method in which the material is excavated, continuously, semi-continuously, or
episodically, by an underground mining method such as a continuous mining
machine,
drill-and-blast, longwall mining, hydraulic mining, mechanical excavation
whether by
backhoes, hydraulic hammers and the like, or by tunnel boring machines
("TBMs") or
any other appropriate underground mining practice. A movable shield may be
used to
provide ground support over the mining apparatus and personnel during
excavating. In
one configuration, a substantially smaller tunnel liner is formed within the
excavation
shield and left in place behind the moveable excavation shield as it advances.
A backfill
material is placed in the excavated volume behind the excavation machine and
around
the access tunnel liner. Preferably, the backfill at least substantially fills
the unsupported
volume and itself is supported by the tunnel liner and, in part, by the
excavation shield
and/or a bulkhead. Typically, the backftll (i.e., the solid particulates and
associated
interstitial or interparticle spaces) fills at least about 65%, more typically
at least about
75% and even more typically from about 85 to about 100% by volume of the space
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defined by the access tunnel liner, the mining machine bulkhead, the bulkhead
(or
backfill retaining member) at the excavation entry, and the surrounding
excavation. The
excavation shield, bulkhead, backfill material and/or tunnel liner all act to
support the
unexcavated ground behind the excavation face. This combination provides
ground
support for the mining operation and a small trailing tunnel or passage for
ingress and
egress from the working face. The backfill material can be tailings from
material
processing operations, previously mined material, currently mined material, or
any other
material having acceptable density and strength characteristics.
The backfill operation can be accomplished by numerous techniques. For
example, a prefabricated liner having a smaller outer boundary than the
surface of the
excavation can be set in place anywhere behind a rear section of the movable
shield, and,
before, during, or after advancement of the shield, the backfill material is
injected or
otherwise placed in the gap or space between the liner, the machine bulkhead,
previously
backfilled material, and the surrounding excavated opening. The trailing
tunnel is
defined by and extends through the liner.
In another configuration, the liner is formed beneath the shield such as using
a
suitable form, and the lining material placed in or on the form and allowed to
set or
become self-supporting while the overlying shield is in position. The liner
can be formed
from any suitable, preferably consolidated, material, such as concrete, grout,
asphalt, or a
combination thereof. The lining material could include previously excavated
material,
whether or not processed for bitumen recovery. When the liner is formed, the
backfill
material can be placed in the gap by suitable techniques. Before injection
into the open
space above the liner, the excavated backfill material could be combined with
a suitable
binder, such as flyash, gypsum, sulphur, slag, and the like, which will
consolidate or
strengthen the backfill material after injection into the open space.
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In another configuration, the access tunnel is formed without a liner by
combining the backfill material with a binder, such as those described above,
placing the
backfill material in place above a tail shield and/or form, permitting the
backfill material
to consolidate and become self-supporting while the tail shield and/or form is
in position,
and thereafter moving the tail shield, removing the form. Alternatively, the
form could
be left in position to further support the consolidated backfill.
The trailing tunnel in the backfilled portion of the excavation is preferably
substantially smaller in cross-sectional area than the same portion of the
excavation
before backfilling. Preferably, the cross-section area of the trailing tunnel
(in a plane
normal to the direction or bearing or longitudinal axis of the tunnel) is no
more than
about 30%, more preferably no more than about 20%, even more preferably no
more than
about 10% and most preferably ranges from about 5 to about 10% of the cross-
section
area (in the same plane) of the excavated portion of the mined volume.
The backfilling of the excavation to define a trailing access tunnel can have
numerous advantages. For example, the trailing access tunnel can have a cross-
sectional
area normal to the long axis of the trailing tunnel that is small enough to
reduce
significantly the likelihood of caving of the excavation during excavation,
thereby
providing enhanced safety for personnel, or of surface subsidence after the
excavation is
completed. This is particularly advantageous in weak overburden conditions,
which are
typically encountered in oil sand excavation. Backfilling can be significantly
less
expensive and more effective than conventional ground support techniques.
Backfilling
can provide a convenient way of disposing of waste materials, such as
potentially toxic
tailings (e.g., clean sands with a high concentration of clay and shale, etc.)
or country
rock (i.e., excavated material containing unprofitable levels of bitumen or
devoid of
bitumen), that are generated during excavation and/or material processing.
Large surface
facilities are not required for tailings or overburden storage. Reclamation
costs, as well
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as short and long term environmental impacts, can thus be greatly reduced. The
per-
tonne costs of mining using any of the methods disclosed herein can be the
same as, or
even less, than the per-tonne mining cost of surface mining techniques on
shallow
deposits. Due to the high level of long-term ground stability associated with
backfilling,
the mining techniques disclosed herein can provide economical access to
valuable
materials in formerly unaccessible areas, such as under industrial facilities
or protected
or otherwise reserved areas, lakes, swamps, muskeg., etc. The methods
disclosed herein
can not only recover bitumen in oil sands deposits previously not economically
recoverable by surface mining or in situ techniques but also can recover
bitumen in oil
sands deposits previously recoverable only by in situ techniques. The methods
are often
preferable to in situ techniques (such as thermal in-situ or chemical in-situ
recovery
processes) due to substantially less energy expenditure per unit of recovered
bitumen.
The methods can recover a substantially higher portion of the economically
viable oil
sands resource (generally regarded as those oil sands containing at least 5%
to 6% by
mass of bitumen) even in the presence of complex and variable mud and shale
layers
within the payzone.
In yet another embodiment of the present invention, a number of possible mine
plans are provided that are particularly applicable to the variety and
diversity of oil sands
deposits. In one configuration, a series of "U"-shaped or concentric circular
drives or
other pattern of drives (in plan view) are formed through the material to be
excavated.
These are typical patterns that may be used when mining from a single high
wall face, as
would be the case when operating at the boundary of an open-pit or surface
mine. The
"U"-shaped excavations typically overlap one another on the turns. The
concentric
circular drives, for example, do not overlap. However, this type of pattern
will leave
some deposits in the center of the pattern that cannot be mined. The "U"-
shaped,
concentric circular drives and other pattern of drives can be used in various
combinations
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to optimize ore recovery in the particular deposit being mined. The various
mining drives
can be started from either end, and can be carried out in any order either
spatially or
temporally as dictated by the layout of the ore body and the time it takes for
backfill to
become consolidated. If backfill strength is insufficient, then a pillar of
unmined ore may
be left in place between adjacent drives. If the backfill is fully
consolidated then adjacent
drives may be made as close as possible or even overlap to some extent. In
another
configuration, where the area to be mined is under a surface obstruction such
as a hill, a
muskeg swamp, a tailings pond or a large mining facility the mining drives can
be a
series of straight runs where the mining machine enters and exits on either
side of the
obstruction, thereby avoiding underground turns. If the mining machine is
smaller in
height than the depth of the ore body, then the above mining patterns can be
repeated on
various levels.
The same or other mining patterns may be applied to deeper deposits where
access would be established by excavating access tunnels or shafts and
creating a large
underground cavern for initiating and ending mining drives. The mining
machines could
be assembled and serviced in these caverns. Alternately, access tunnels or
shafts and
large underground caverns can be installed on both sides of a large deposit so
that the
back and forth mining pattern discussed above for mining under surface
obstructions can
be applied to deeper deposits.
The foregoing summary is neither complete nor exhaustive. As will be
appreciated, the above mining patterns may be varied to suit the local
conditions and can
be combined or used in other configurations or embodiments that may be
different from
those set forth above. These mine layouts can be used with any mining method
including
a continuous mining machine, drill-and-blast techniques, a TBM and the like.
In another embodiment, the excavated material is fully or partially processed
in
the underground excavation to recover the valuable components of the material.
The
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material can be excavated using any mining process, including those described
above. In
one configuration, the excavated material is further comminuted in the
excavation, such
as by a crusher and/or grinder, formed into a slurry, and hydrotransported out
of the
excavation for further processing. The waste material, or tailings, can be
formed into a
second slurry at an external location and hydrotransported back into the
excavation for
use in backfilling. Alternatively, the backfill slurry can be formed from a
high proportion
of mature fine tailings ("MFTs") from previous surface mining operations and
thereby
provide for environmentally safe disposal of these wastes. The tailings from
the
excavated oil sands are processed to remove sand (which is a relatively
valuable
commodity and/or may be disposed of readily) and the sands replaced in the
second
slurry formed from MFTs and other less valuable tailings components, such as
from both
the present and previous mining operations. Surge tanks can be used to handle
fluctuations in the slurry volume.
In yet another embodiment, a tunnel boring machine is provided that is
particularly suited for use in unstable overburden conditions. As used herein,
a "tunnel
boring machine" or TBM refers to an excavation machine including one or more
movable shields for ground support. Typically, the TBM will be a rotary
excavator
including a shield, an excavating or cutting wheel and some wheel-driving
apparatus. In
one configuration, the hood of the forward portion of the movable shield(s)
controls
overburden and protects the excavation area, the body of the shield(s) houses
the
working mechanisms and one or more tail shields furnish ground support during
the
tunnel lining installation. In the typical TBM design, the cutting wheel is
designed to
perform three main functions: excavating, spoil removal and face support. The
TBM can
have one or more mining devices at its forward end. Such mining devices can be
any
suitable ground removal device, such as a rotary cutting head, a hydraulic
jet, a shovel, a
backhoe, a ripper or any combination of these devices. In the case of a rotary
cutting
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head, an array of drag bits, an array of picks, an array of disc cutters and
the like or any
combination of cutting tools arrayed on the cutting head may be used. In
another
configuration, a tunneling machine can also be fully enclosed (a closed face
machine)
and capable of applying a pressurized slurry at the cutting face to provide,
for example,
stability to the excavation face. These machines are often referred to as
slurry or slime
machines or as earth pressure balance machines or as earth pressure balance
systems.
In one configuration, the tunneling machine includes two or more shields of
different sizes may be used to provide ground support. In one configuration, a
large
shield (in cross-sectional area) may be located at the front of, over, and/or
behind the
machine to support the ground over the excavation and backfill operations. A
small
shield (in circumference) may be located behind the large shield and used to
support the
ground above the trailing access tunnel until the access tunnel becomes self-
supporting
or assembled.
In one configuration, the machine includes two or more (typically overlapping)
tail shields or tail shrouds, each providing ground support. For example, a
backfill tail
shield, having substantially the same circumference as the main excavation
surface (in
the same plane), can extend behind the primary excavation shield to protect
the backfill
injection apparatus and the backfill volume from loose and falling ground from
the
unexcavated material. A typically substantially smaller tail shield (in
circumference
determined in the same plane) can extend behind the primary excavation shield
and/or
machine bulkhead to provide protect liner fabrication personnel and machinery
from
loose or falling ground or from previously backfilled material, until the
liner has
achieved sufficient strength to provide such protection. A binocular tunneling
machine
may have two large backfill shields and one or more smaller (in cross-section)
access
tunnel tail shields.
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In one configuration, the body member has a plurality of interconnected
segments that movably engage one another. In one design, the adjacent segments
are
interconnected by a plurality of hydraulic jacks or cylinders. The hydraulic
cylinders on
the trailing section can push against the liner or backfill material to
advance the trailing
section, thereby more effectively engaging adjacent liner sections and/or
compacting the
backfill material. In one design, the adjacent segments telescopically engage
one another.
The machine can have any number of segments including only one, though two or
more
segments are preferred. The segmentation allows the machine to change
direction
efficiently and allows the machine to follow the meandering oil sands
deposits. In one
embodiment, the segmentation also permits the machine to advance, one segment
at a
time, by the moving segment thrusting against the combined static friction of
the
stationary segments.
In one configuration, the segmented machine is propelled forward by a
combination of soft-ground grippers and thrusting off the backfill material.
The grippers
can be of any suitable design, as will be appreciated by those of ordinary
skill in the art.
Soft-ground grippers are typically hydraulically actuated pads that can be
thrust out
against the sides of the excavation. The pads may be large so as to contact a
large area of
a soft-ground ore body. Each section or segment of the tunneling machine can
further
include one or more such grippers for displacing and maneuvering the machine
and
providing thrust for the mining device(s) at the forward end of the machine.
The rear
segment of the machine can thrust off the backfill since the cross-sectional
area or outer
periphery of backfill is approximately the same as the cross-sectional area or
outer
periphery of the excavation. This form of propulsion also has the advantage of
helping to
compact and consolidate the backfill.
In segmented designs, the segmented tunneling machine typically advances in an
inch worm fashion through the material to be excavated leaving behind a tunnel
of
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suitable shape. For a tunneling machine having at least three segments, the
typical steps
for advancing the machine are, for example, as follows:
(a) advancing a first section of the tunneling machine forward, wherein the
first section is advanced by pushing against an adjacent second section of
the tunneling machine;
(b) when the first section is advanced relative to the second section a
selected
distance, pulling, with the first section, the second section forward and/or
pushing, with at least one trailing section, adjacent to the second section,
the second section forward; and
(c) when the second section is advanced relative to a trailing section the
selected distance, pulling with the first and second sections and/or
pushing off the backfill material behind the tunneling machine to move at
least one trailing section forward.
As will be appreciated, machines have one or two segments can advance using
fewer
steps than those set forth above.
In one configuration, the TBM includes a global positioning system and/or
fibre
optic surveying line to continuously determine the position of the machine.
In one configuration, the TBM includes one or more sensing devices for
detecting the presence of hydrocarbons or other valuable components or barren
ground or
shale and calcite lenses and the like or another characteristic in the in-situ
material to be
excavated, and/or the presence or hydrocarbons or other valuable components
material
that has been excavated. The sensing devices can use sonar and/or ground-
penetrating
radar or other short range underground detection technologies to sense the
features ahead
of the mining machine.
In one configuration, the TBM machine has features permitting the TBM to
change direction or steer. Such machines can steer by any number of means or
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combination of means. For example, a segmented machine can steer by extending
and
retracting its connecting hydraulic propulsion cylinders by different lengths
of extension
or retraction around the circumference of the machine. A TBM machine may
change
direction by differentially extending, retracting and reorienting the cutter
tools on its
rotary cutting head to assist in steering. The TBM may also steer by
articulating its
cutting head. The TBM may also deploy large flaps or grippers to create
increased drag
on the side of the machine so as to cause the machine to steer in that
direction. Such
maneuverability permits the TBM to mine patterns such as described herein as
well as
mine around barren ground or around obstacles. As will be appreciated, the
above
methods of steering may be varied to suit the local conditions and can be
combined or
used in other configurations or embodiments that may be different from those
set forth
above.
In one configuration, the tunneling machine has an excavation head configured
to form an approximately rectangular excavation cross-section which may be
more suited
to some ore bodies. A rectangular excavation can be formed by rotary cutting
head
assemblies in a number of ways which include assembling an array of circular
cutter
heads, tilting a circular head and using one or more triangular heads that
rotate
eccentrically by the use of offset planetary gear drives for example. The
preferred
embodiment for excavating a rectangular opening would incorporate two or more
conventional tunnel boring machine heads in a binocular or even trinocular TBM
configuration. Such machines have been built and used in various civil
tunneling
applications.
In one configuration, the tunneling machine is configured to excavate the in
situ
material by slurry techniques so that the mined material is immediately formed
into a
format that is compatible with slurry pipeline or hydrotransport methods. In
this
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configuration, the mined material is typically not handled as a solid and thus
tends to be
less abrasive and cause less wear on any of the materials handling
apparatuses.
In one configuration, the tunneling machine includes a hydrocarbon extraction
unit, such as a bitumen separation apparatus. The apparatus extracts the
hydrocarbons
and the extracted hydrocarbons are transported to a surface facility for
further
processing. In this manner, less material can be transported to the surface,
thereby
decreasing haulage costs. The waste material, which is still in the excavation
area can be
used for backfilling as noted previously.
In one configuration, the tunneling machine includes a heat exchange system
for
absorbing heat from any heat sources in the tunneling machine, such as the
propulsion
motors and hydraulic cylinders used to move the machine segments, and
transferring the
absorbed heat to the material in a slurry formed at or near the cutting head,
the bitumen
processing chamber, personnel compartment, lining material formation units,
and/or the
hydrotransport system. The heat exchanger can be of any design, as will be
appreciated
by those of ordinary skill in the art.
In one configuration, the tunneling machine includes a pressurized chamber
having a pressure greater than the formation pressure of the unexcavated
material to
inhibit formation gases such as methane from entering personnel areas. The
method can
require only a small fraction, typically less than 5% to 10%, of the output
crude oil
energy, to power the excavation and bitumen recovery process.
In one configuration, the mining machine further includes device(s) for
forming
tunnel lining sections. Such devices can be forms, lifting devices such as
cranes to
manipulate the forms or prefabricated liners, injecting assembly for injecting
or spraying
the backfill material around the liner, asphalt formation machine(s) for
forming a lining
material, concrete mixing machine(s), machines for extruding cast-in-place
liners and the
like.
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In a further embodiment, a system is provided for collecting formation gases
from or injecting waste gases into a formation. The system includes the
following:
a rock bolt assembly, the rock bolt assembly including an internal passageway
connected to one or more outlet ports that communicate with an underground
formation;
a gas handling system for transporting gases from or to the rock bolt
assembly;
and
a valve assembly engaging the head of the rock bolt assembly and being in
communication with the gas handling system, whereby gases are withdrawn from
or
injected into the underground formation. When the tunneling machine excavates
hydrocarbon deposits, it can encounter gas either in the form of free gas
contained in
structural pockets or in the form of a bound gas dissolved in the formation
water and
hydrocarbon material. When the excavated volume is exposed to significantly
lower
pressure such as atmospheric pressure, the dissolved gas will come out of
solution and
flow towards the excavation. The flow rate will be limited by the local
permeability. The
rock bolt assembly can be inserted through a tunnel liner and used as conduits
for
draining formation gas to reduce the pressure on the tunnel liner.
In yet another embodiment, a method for disposing of gases in abandoned
excavations is provided. The gases are transported into an underground
excavation, such
as using the gas handling system described above, and injected into an
underground
formation accessible through the underground excavation. An extension of the
present
invention is to use the network of trailing access tunnels as repositories for
greenhouse
and other noxious gases after they have been abandoned as part of the mining
process. In
this embodiment, the tunnel liner(s) is/are perforated and the tunnel
entrances (both
entrance and exit portals) as well as any connections between active tunnels
are closed
off. The tunnel liners can be perforated in any number of ways. For example,
shaped
charges can be affixed to the tunnel walls and initiated remotely to perforate
the walls.
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Alternatively, the injecting can be done with a number of properly dispersed
rock bolt
assemblies. Then, the desired gases can be pumped into the access tunnels
under
sufficient pressure such at the gases would be slowly injected into the
surrounding
formation via the tunnel liner perforations.
The foregoing summary is neither complete nor exhaustive. As will be
appreciated, the above features can be combined or used in other
configurations or
embodiments that may be different from those set forth above. For example, one
or more
of the features can be used in mining processes that do not use the backfill
feature. Such
other configurations and embodiments are considered to be part of the present
invention.
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BRIEF DESCRIPTION OF THE DRAWINGS
Figure 1 shows a cross-sectional a view of a mining machine of the present
invention excavating a soft ore deposit entering from a prepared face.
Figure 2 shows a schematic side view that illustrates the basic mining process
of
the present invention.
Figure 2A shows a schematic side view that illustrates the basic mining
process
in accordance with one embodiment of the present invention.
Figure 2B shows a schematic side view that illustrates the basic mining
process
in accordance with another embodiment of the present invention.
Figure 3 shows an isometric front view of the mining machine of the present
invention illustrating a typical size comparison of the excavation cross-
section and the
trailing access tunnel cross-section.
Figure 4 shows an isometric rear view of a large excavating machine with two
rotary cutter heads that can excavate a roughly rectangular excavation opening
and leave
a small trailing access tunnel.
Figure 5 shows a side view of a possible layout for the principal interior
components of a TBM mining machine in which the excavated material and
backfill
material are isolated from the personnel in the interior of the machine.
Figure 6 shows plan view of a mining pattern applicable to a high wall entry
for
a large mining machine.
Figure 7 shows plan view of an alternate mining pattern applicable to a high
wall
entry for a large mining machine.
Figure 8 shows a plan view of a mining pattern applicable to a deposit that
can
be entered from either side.
Figure 9 is an end view of a fully supported cavern used as a staging area for
deposits not accessible from the face of an open-pit or a high wall entry.
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Figure 10 is a plan view of a feasible underground staging area for machines
to
excavate a mining pattern similar to those patterns applicable to a high wall
entry.
Figure 11 shows a side view depicting how mining patterns can be applied to
different levels of an underground deposit.
Figure 12 shows a front view illustrating the most efficient method of
configuring adjacent mining drives using cylindrical TBMs.
Figure 13 shows a side view and a rear view of a mining machine typical of the
present invention illustrating a large backfill tail shroud and a small access
tunnel tail
shroud.
Figure 14 shows a sequence of cross-sectional side views of the mining process
in which the access liner is formed by adding liner segments and the backfill
is added at
different intervals.
Figure 14A shows a first figure in a sequence of cross-sectional side views of
the
mining process in which the access liner is formed by adding liner segments
and the
backfill is added at different intervals.
Figure 14B shows a second figure in a sequence of cross-sectional side views
of
the mining process in which the access liner is formed by adding liner
segments and the
backfill is added at different intervals.
Figure 14C shows a third figure in a sequence of cross-sectional side views of
the mining process in which the access liner is formed by adding liner
segments and the
backfill is added at different intervals.
Figure 14D shows a fourth figure in a sequence of cross-sectional side views
of
the mining process in which the access liner is formed by adding liner
segments and the
backfill is added at different intervals.
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Figure 14E shows a fifth figure in a sequence of cross-sectional side views of
the
mining process in which the access liner is formed by adding liner segments
and the
backfill is added at different intervals.
Figure 15 shows a sequence of cross-sectional side views of the mining process
in which the access liner is formed by adding liner segments and the backfill
is
continuously deposited so as to leave no empty volume behind the machine.
Figure 15A shows a first figure in a sequence of cross-sectional side views of
the
mining process in which the access liner is formed by adding liner segments
and the
backfill is continuously deposited so as to leave no empty volume behind the
machine.
Figure 15B shows a second figure in a sequence of cross-sectional side views
of
the mining process in which the access liner is formed by adding liner
segments and the
backfill is continuously deposited so as to leave no empty volume behind the
machine.
Figure 15C shows a third figure in a sequence of cross-sectional side views of
the mining process in which the access liner is formed by adding liner
segments and the
backfill is continuously deposited so as to leave no empty volume behind the
machine.
Figure 15D shows a fourth figure in a sequence of cross-sectional side views
of
the mining process in which the access liner is formed by adding liner
segments and the
backfill is continuously deposited so as to leave no empty volume behind the
machine.
Figure 16 shows a sequence of cross-sectional side views of the mining process
in which the access liner is formed by continuously forming an extruded liner
and the
backfill is continuously deposited so as to leave empty volume behind the
machine.
Figure 16A shows a first figure in a sequence of cross-sectional side views of
the
mining process in which the access liner is formed by continuously forming an
extruded
liner and the backfill is continuously deposited so as to leave empty volume
behind the
machine.
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Figure 16B shows a second figure in a sequence of cross-sectional side views
of
the mining process in which the access liner is formed by continuously forming
an
extruded liner and the backfill is continuously deposited so as to leave empty
volume
behind the machine.
Figure 16C shows a third figure in a sequence of cross-sectional side views of
the mining process in which the access liner is formed by continuously forming
an
extruded liner and the backfill is continuously deposited so as to leave empty
volume
behind the machine.
Figure 16D shows a fourth figure in a sequence of cross-sectional side views
of
the mining process in which the access liner is formed by continuously forming
an
extruded liner and the backfill is continuously deposited so as to leave empty
volume
behind the machine.
Figure 17 shows front views of various ways in which arrays of rotary cutter
heads can be arranged to excavate circular or rectangular openings.
Figure 17A shows a front view of one way in which arrays of rotary cutter
heads
can be arranged to excavate circular or rectangular openings.
Figure 17B shows a front view of another way in which arrays of rotary cutter
heads can be arranged to excavate circular or rectangular openings.
Figure 17C shows a front view of yet another way in which arrays of rotary
cutter heads can be arranged to excavate circular or rectangular openings.
Figure 18 shows a several views of a cutter head assembly comprised of both
mechanical cutter elements and water jet cutter elements.
Figure 18A shows a cross sectional side view of a cutter head assembly
comprised of both mechanical cutter elements and water jet cutter elements.
Figure 18B shows a side and isometric view of a cutter head assembly comprised
of both mechanical cutter elements and water jet cutter elements.
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Figure 19 shows a rear view of a large excavating machine with two rotary
cutter
heads illustrating the cross section of a trailing access tunnel and various
other features.
Figure 20 shows an isometric view looking down of some of the elements of a
possible mining operation using tunnel boring machines entering and exiting at
an
exposed working face.
Figure 21 shows an isometric view of the portal area of a possible mining
operation using tunnel boring machines entering and exiting at an exposed
working face.
Figure 22 shows an isometric schematic view of a machine that can lift and
turn
a large TBM.
Figure 23 shows a flow chart of the oil sands material as it passes through
the
mining machine.
Figure 24 shows a flow chart of the oil sands material as it passes through
the
mining machine for the case where bitumen or heavy oil is separated from the
oil sands
in the machine.
Figure 25 shows a side view of a TBM mining machine in which the flow of
excavated material and backfill material is isolated from the personnel in the
interior of
the machine.
Figure 26 shows a side schematic view of a TBM mining machine illustrating the
volumes occupied by both outgoing oil sand or bitumen slurry and incoming
tailings
slurry.
Figure 27 shows a possible embodiment of a heat exchange system to utilize
waste heat for heating a slurry at the working face.
Figure 28 shows a side schematic view of a possible placement of surge control
chambers for controlling outgoing and incoming slurry pipelines.
Figure 28A shows a side schematic view of one possible placement of surge
control chambers for controlling outgoing slurry pipelines.
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Figure 28B shows a side schematic view of one possible placement of surge
control chambers for controlling incoming slurry pipelines.
Figure 29 shows a side view of a sequence of machine motions for a large
segmented excavating machine that advances by utilizing differential friction
as a means
of propulsion.
Figure 29A shows a first side view of a sequence of machine motions for a
large
segmented excavating machine that advances by utilizing differential friction
as a means
of propulsion.
Figure 29B shows a second side view of a sequence of machine motions for a
large segmented excavating machine that advances by utilizing differential
friction as a
means of propulsion.
Figure 29C shows a third side view of a sequence of machine motions for a
large
segmented excavating machine that advances by utilizing differential friction
as a means
of propulsion.
Figure 29D shows a fourth side view of a sequence of machine motions for a
large segmented excavating machine that advances by utilizing differential
friction as a
means of propulsion.
Figure 29E shows a fifth side view of a sequence of machine motions for a
large
segmented excavating machine that advances by utilizing differential friction
as a means
of propulsion.
Figure 29F shows a sixth side view of a sequence of machine motions for a
large
segmented excavating machine that advances by utilizing differential friction
as a means
of propulsion.
Figure 29G shows a seventh side view of a sequence of machine motions for a
large segmented excavating machine that advances by utilizing differential
friction as a
means of propulsion.
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Figure 29H shows a eighth side view of a sequence of machine motions for a
large segmented excavating machine that advances by utilizing differential
friction as a
means of propulsion.
Figure 291 shows a ninth side view of a sequence of machine motions for a
large
segmented excavating machine that advances by utilizing differential friction
as a means
of propulsion.
Figure 30 shows a side view of several means for a large shield machine to
execute an underground turn.
Figure 30A shows a side view of a large shield machine in accordance with one
embodiment of the present invention.
Figure 30B shows a side view of several means for a large shield machine to
execute an underground turn.
Figure 31 shows an isometric view of a possible the hydraulic cylinder
arrangement for propulsion and steering of a multi-segmented machine with two
rotary
cutter heads.
Figure 32 illustrates a large one-segment TBM mining machine that can be
steered by a combination of cutter head movements and thrust backplate
movements.
Figure 33 shows sequence illustrating how a large mining machine of the
present
invention can execute an underground turn.
Figure 33A shows a first figure in a sequence illustrating how a large mining
machine of the present invention can execute an underground turn.
Figure 33B shows a second figure in a sequence illustrating how a large mining
machine of the present invention can execute an underground turn.
Figure 33C shows a third figure in a sequence illustrating how a large mining
machine of the present invention can execute an underground turn.
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Figure 34 shows an apparatus for forming an extruded liner and a side view of
soft-ground grippers.
Figure 34A shows a cross sectional side view of a mining machine in accordance
with one embodiment of the present invention.
Figure 34B shows an isometric view of a mining machine in accordance with one
embodiment of the present invention.
Figure 34C shows an isometric view of a liner form of a mining machine in
accordance with one embodiment of the present invention.
Figure 34D shows a cross sectional view of a gripper plate of a mining machine
in accordance with one embodiment of the present invention.
Figure 35 shows an isometric view of a possible extruded access liner which
contains pipelines and other ducts and conduits formed within the liner
material.
Figure 36 shows several views a binocular type TBM with dual trailing access
tunnels.
Figure 36A shows a side view of a binocular type TBM with dual trailing access
tunnels.
Figure 36B shows a top view of a binocular type TBM with dual trailing access
tunnels.
Figure 36C shows an isometric view of a binocular type TBM with dual trailing
access tunnels.
Figure 36D shows a cross sectional view of a binocular type TBM with dual
trailing access tunnels.
Figure 37 shows a plan view of access tunnels in the formation with cross-
connecting tunnels to provide entry to neighboring access tunnels to assist in
emergency
escape.
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Figure 38 shows an isometric view of the front-end of boring machine that uses
a
hydraulically actuated shovel/scoop for excavating in relatively soft rock or
soil and a
combination backhoe/hydraulic hammer attachment that can be used in harder
ground.
Figure 38A shows a side view of a boring machine with a combination
backhoe/hydraulic hammer attachment that can be used in harder ground.
Figure 38B shows an isometric view of the front-end of a boring machine that
uses a hydraulically actuated shovel/scoop for excavating in relatively soft
rock or soil.
Figure 39 shows an isometric view of a large multi-segmented excavating
machine with two triangular cutter heads that can excavate a rectangular
excavation
opening and leave a small trailing access tunnel.
Figure 40 shows isometric schematic views of a telescoping slurry pipe
apparatus.
Figure 40A shows an isometric view of the end of a telescoping slurry pipe
apparatus.
Figure 40B shows a side view of the sections of slurry pipe in both an
extended
and retracted state.
Figure 40C shows an isometric view of the end of a fully or nearly fully
extended section of telescoping slurry pipeline.
Figure 41 shows a side schematic view of a slurry pipeline system where a
flexible pipeline is used to advance a fixed slurry line section.
Figure 41A shows a first side schematic view of a slurry pipeline system where
a
flexible pipeline is used to advance a fixed slurry line section.
Figure 41B shows a second side schematic view of a slurry pipeline system
where a flexible pipeline is used to advance a fixed slurry line section.
Figure 41 C shows a third side schematic view of a slurry pipeline system
where
a flexible pipeline is used to advance a fixed slurry line section.
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CA 02583519 2007-04-20
Figure 41D shows a fourth side schematic view of a slurry pipeline system
where
a flexible pipeline is used to advance a flxed slurry line section.
Figure 42 shows a side schematic view of a special rock bolt that penetrates
an
access tunnel wall and can be used to tap gas from or inject gas into a
surrounding
formation and an isometric schematic illustrating how such rock bolts can be
positioned
around an access tunnel.
Figure 42A shows a side schematic view of a special rock bolt that penetrates
an
access tunnel wall and can be used to tap gas from a surrounding formation.
Figure 42B shows a side schematic view of a special rock bolt that penetrates
an
access tunnel wall and can be used to inject gas into a surrounding formation.
Figure 42C shows an isometric view of how special rock bolts can be positioned
around an access tunnel.
Figure 43 shows some of the various cutter tools that can be used on TBM
cutter
heads.
DETAILED DESCRIPTION OF THE DRAWINGS
The foregoing discussion of the invention has been presented for purposes of
illustration and description, the foregoing is not intended to limit the
invention to the
form or forms disclosed herein. Although the description of the invention has
included
description of one or more embodiments and certain variations and
modifications, other
variations and modifications are within the scope of the invention, e.g., as
may be within
the skill and knowledge of those in the art, after understanding the present
disclosure. It
is intended to obtain rights which include alternative embodiments to the
extent
permitted, including alternate, interchangeable and/or equivalent structures,
functions,
ranges or steps to those claimed, whether or not such alternate,
interchangeable and/or
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CA 02583519 2007-04-20
equivalent structures, functions, ranges or steps are disclosed herein, and
without
intending to publicly dedicate any patentable subject matter.
Overview of the Method
The method described in the present invention can be adapted to underground
mining of deposits that are relatively easy to excavate by known technologies
but require
ground support behind the advancing machine to avoid cave-ins, surface
subsidence or
ground heaving. This invention involves, in part, substantially reducing the
cross-section
of the trailing tunnel with respect to the cross-section of the ground
excavated and
therefore removes the requirement for expensive ground support while
eliminating any
significant ground movement of the unexcavated ground. The invention reduces
the
economics of underground recovery to approximately those of currently
practiced open-
pit mining operations and possibly less since it eliminates the need to remove
overburden
and can reduce the size of tailings ponds required.
Figure 1 shows a cross-sectional a view of a tunneling machine 100 mining into
an oil sand deposit 103 from a prepared face 101 which has been formed by
removing
overburden material 102 to expose the oil sand deposit 103. The oil sand
deposit 103
typically lies on top of a basement rock 104 and under the overburden 102. The
mining
machine 100 advances and mines into the oil sand 103 by excavating oil sand
material
103 through the front end 105 which may be, for example, a rotary cutter head.
As the
mining machine 100 advances, an access tunnel liner 106 is formed inside the
machine
100. As the machine 100 advances, the liner 106 remains in place and is left
behind the
advancing machine 100. Also as the machine 100 advances, material is deposited
as
backfill 108 behind the machine 100 through one or more openings 107 in the
rear of the
machine 100. The backfill 108 surrounds the liner 106 leaving an access tunnel
109. The
machine 100, the liner 106 and the backfill 108 all act to support the
remaining oil sand
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CA 02583519 2007-04-20
103 and overburden 102 such that there is insignificant motion of the ground
surface
110. A ramp 111 which allows the mining machine 100 to position itself in at
the
entrance portal 112 for the start of its mining drive is also shown.
Figure 2 illustrates an example of the basic mining machine steps for a three
segment mining machine that advances while injecting and compacting backfill
material
into the volume behind the machine but outside the trailing access tunnel.
Injecting
backfill material into the volume behind the machine as the volume is created
is most
preferred because it eliminates the need for temporary ground support behind
the aft-
most segment as it advances. Figure 2a illustrates the position of the machine
at the
beginning of a cycle. The forward most segment 200 contains the excavating
apparatus at
the head 201 of the segment 200. The middle segment 202 may have some form of
gripper system (not shown) to maintain its position against the wall 203 of
the
excavation. The aft most segment 204 is shown in its initial position where
the ground
205 behind the segment 204 is completely backfilled. The trailing access
tunne1206 has
been installed and connects the surface (not shown) to the aft most segment
204. Figure
2b illustrates how the forward most and aft most segments advance. As the aft
most
segment 204 is pulled forward by push jacks, for example, connecting it with
the middle
segment 202, backfill material inside the machine is injected into the volume
207 being
created by the advancing aft most segment 204. This process continues until
the aft most
segment 204 is fully advanced. The aft most segment 204 can also use its push
jacks to
thrust against the injected backfill material 207 to compact it, if necessary
and help
propel the aft most segment. As the aft-most segment 204 advances, the access
tunnel
has been extended to form a new section which is left in place and covered by
injected
backfill materia1207. At or about the same time as the aft most section 204 is
advanced,
the forward most section 200 advances by push jacks, for example, connecting
it with the
middle segment 202. As the foremost segment 200 advances, it excavates new ore
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CA 02583519 2007-04-20
material 208 using its excavating apparatus in the excavating head 201. After
the forward
most segment 200 and the aft most segment 204 have completed their advance,
the
middle segment 202 is moved forward by its hydraulic jacks until the machine
assumes
the configuration shown in Figure 2a. As shown, the front of segment 200 has
advanced
a distance 209 and the rear segment 204 has also advanced a distance 209 from
the
positions indicated in Figure 2a to the positions in Figure 2b. In this way,
ore has been
excavated, backfill material has been placed and the access tunnel has been
extended
without significantly disturbing the unexcavated ground. The machine can
change
direction by differentially extending or retracting its hydraulic jacks in the
appropriate
manner during the motion of each individual segment.
Figure 3 shows an isometric front view of the mining machine of the present
invention illustrating a typical size comparison of the excavation cross-
section and the
trailing access tunnel cross-section. In soft ground or soft rock, tunnel
boring machines
can be advanced by thrusting against the tunnel liner structure which has
approximately
the same cross-sectional geometry as the boring machine. In one embodiment of
the
present invention, only a small tunnel liner is left behind so the machine
must be
propelled forward by other means. In this configuration, the mining machine
may be
formed, for example, by two telescoping segments and propelled forward by
conventional soft-ground grippers which thrust against the walls of the
excavation and by
the aft most segment thrusting against the backfill or by a combination of
both means of
propulsion. In the present invention, it may be necessary to use large soft-
ground
grippers to provide machine propulsion and cutter head thrust as (1) the only
means of
propulsion and thrust; or (2) as the principal means of propulsion and thrust
where the
machine can also thrust against the backfill when additional propulsion and
thrust are
required; or (3) as an auxiliary means of propulsion and thrust where the
principal means
of propulsion and thrust are against the backfill. This combination of
propulsion and
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CA 02583519 2008-04-10
thrust techniques allows the backfill operations to be decoupled from the
propulsion and
cutter head thrust. This combination also allows the backfill to be compacted
separately
from propulsion and cutter head thrust.
Figure 3 shows an example of a tunnel boring mining machine 300 that can be
propelled by using external grippers 301 and 302. The rear section 303 of the
machine is
shown with full circumferential grippers 302 that grip by being pushed out
against the
excavation walls, usually by hydraulic rams. When the rear section 303
grippers 302 are
pushed out against the excavation walls, the forward section 304 of the
machine, which
includes the cutter head 305, can thrust forward by pushing against the rear
section 303.
Once the forward section 304 is fully or almost fully extended, then the
retracted
grippers 301 on the forward section 304 can be pushed out against the
excavation walls
while the grippers 302 on the rear section 303 are retracted. Now, hydraulic
cylinders
inside the machine (not shown) can retract and draw the rear section 303 of
the mining
machine forward. This is an example of a propulsion cycle for a two segment
machine.
As noted previously, the rear section can also thrust off the backfill 306
behind the
machine and around the trailing access tunnel tail shield 307, if necessary.
The diameter
308 of the mining machine 300 is typically in the range of about 10 to about
20 meters.
The trailing access tunnel tail shield 307 is much smaller in cross-sectional
area having a
typical dimension 309 in the range of about 2.5 to about 4 meters.
Figure 4 shows an isometric rear view of a large excavating machine 400 with
two rotary
cutter heads 401 and 402 that can excavate a roughly rectangular excavation
opening and
leave a small trailing access tunnel. The rotation of the cutter heads 401 and
402 may
synchronized so that the areas excavated by each have some overlap. The cutter
heads
401 and 402 may also be counter rotated to substantially reduce the tendency
of the
machine 400 to roll. The smaller cross-section trailing access tunnel tail
shield 403 is
shown extending from the rear of the advancing machine. As an example, four
backfill or
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CA 02583519 2008-04-10
spoil discharge pipes 404 for injecting backfill material in the volume behind
the
advancing machine are shown protected from falling ground from above by a
large tail
shield 405. The trailing access tunnel liner is formed inside the machine 400
and
protected from falling ground and backfill material by the smaller tail shield
403. The
diameter 406 of one of the cutter heads of the mining machine 400 is typically
in the
range of about 7 to about 15 meters and the cross-sectional area excavated by
the
machine 400 is therefore about twice the cross-sectional area of one cutter
head. The
trailing access tunnel tail shield 403 is much smaller in cross-sectional area
having a
typical dimension 407 in the range of about 2.5 to about 4 meters.
Figure 5 shows a possible layout for the principal interior and exterior
components of a TBM mining machine of the present invention. The cutter head
assembly 500 is driven by a main cutter head motor (not shown) through a main
bearing
501. The cuttings are directed into a crusher 502 and then into a muck chute
503 which
may be housed in a pressurized chamber 504. The muck chute 503 goes through a
bulkhead 505 and into a large enclosure 506 which may be a bitumen separator
or a
surge tank or an apparatus for forming an oil sands slurry. Also shown are
hydraulic
cylinders 507 for propulsion and steering and electric motors 508 for power.
The oil sand
ore or bitumen is sent out of the access tunnel 509 via a slurry pipeline 510.
The backfill
material, whether produced in the machine by a bitumen separator apparatus or
externally and hydrotransported into the machine via a slurry pipeline 510, is
sent to a
de-watering apparatus 511 where the de-watered backfill material is
transported to
discharge pipes 512 for backfilling the volume inside the large tail shield
513 and around
the small tail shield 514 in which the access tunnel liner 509 may be formed.
In this
configuration, the hydraulic cylinders 508 can be used to push or pull the
interior
bulkhead 515 with respect to the rear bulkhead 516. The cylinders 508 may pull
the rear
bulkhead 516 forward to allow backfill material to be discharged and to
advance the rear
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CA 02583519 2007-04-20
segment 518 of the mining machine. The cylinders 508 may push against the rear
bulkhead 516 to compact the backfill material and to advance the forward
segment 517
of the mining machine. The rear cross-sectional view also shows utility lines
519 (water,
electrical, sewage for example) and a ventilation duct 520.
MiningPatterns
The foregoing has illustrated the basic soft-ore mining process of the present
invention. The next series of drawings illustrate how the soft-ground mining
machines of
the present invention may mine ore deposits that are either accessible from
the surface or
may have to be accessed from an underground cavern or the like formed to allow
the
machines to mine deeper ore deposits.
In one embodiment, a machine or machines are provided to excavate a pattern
that can mine out a volume of oil sands deposits that is approximately 1,600
meters by
1,600 meters for example. In general, the height of the excavating machine
will be
considerably less than the depth of the economically recoverable deposits. The
machine
envisioned will be capable of mining out one or more levels. By combining the
patterns
of excavation described below and machines that can excavate adjacent or
nearly
adjacent openings, the method can process from about 75% to about 95% or more
of the
economically viable oil sands deposits. The method is not restricted to square
or
rectangular areal deposits. The method can be applied to large irregular
deposits by
fitting a pattern of adjacent runs as long as each run is compatible with the
turning radius
of the mining machine. The length of an individual mining drive can be
increased as the
ability to extend utilities and provide maintenance services improves with
time and
experience.
In one configuration, a machine begins a run at an accurately known position
by
global positioning satellite (GPS) techniques, for example. The required
positional
accuracy is about 1 to 3 meters which is within currently available GPS
technology.
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CA 02583519 2007-04-20
During the run, the position of the machine can be continuously updated by
using a fibre
optic surveying line that is maintained along the access tunnel behind the
machine and by
an on-board gyroscopic inertial guidance system. The machine can sense the
geology
ahead of its advance by using an acoustic imaging system capable of mapping
the
geology at a range of approximately 20 to 100 meters. The acoustic imaging
system
would be based on an active acoustic source, sensitive acoustic receivers, and
data
inversion software that translates the return pulses into a rough image of the
geology.
The acoustic system would operate in the frequency range of approximately 50
Hz to
about 500 Hz. Accurate knowledge of the machine's position and of the local
geology of
ahead of the machine should allow the operator's to excavate and mine areas of
economic
deposits as determined by prior surface exploration. Such surface exploration
using
seismic surveys, core hole and acoustic imaging methods is carried out for all
methods of
recovery, including open-pit, and is not an activity that is specifically
required by the
present invention. Ground penetrating radar technology can also be used to
sense the
geology ahead of the advancing machine. A practical ground penetrating radar
system
suitable for the present invention can resolve features as small as '/< meter
in typical
dimension.
A proposed excavation pattern that can be applied to a large square section of
oil
sands deposits by a large excavating machine is illustrated in the plan views
of Figure 6.
A mining drive is started from a portal 600 at an exposed face 601 and may
follow an
approximately U shaped or horseshoe shaped path such as 602 and exit at
another portal
603. The machine can then be bought out and overhauled in preparation for the
next
mining drive. The next drive may begin at any desired location and in any
desired
direction, such as for example, at portal 604 along path 605 and exiting at
portal 606. It
may be preferable to do subsequent mining drives that are not adjacent so that
the
backfill material from a mining drive has as long a time as possible to become
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CA 02583519 2007-04-20
consolidated before an adjacent mining drive is conducted. The pattern
described herein
would be conducted at one level of the ore body and, as more drives are made,
the
mining machine would have to excavate through old access tunnels or maneuver
around
or over the abandoned access tunnels at the outer limit 607 of the area to be
mined. The
mining machines of the present invention may excavate through old access
tunnels,
preferably if these abandoned access tunnels are filled with old tailings or
some other
material that could be excavated and the tunnel liners were formed from a
material such
as unreinforced concrete. The advantage of this type of pattern is that most
of the ore
deposit can be mined. A typical dimension 608 for this pattern is in the range
of
approximately 500 meters to 5,000 meters.
Figure 7 shows plan view of an alternate mining pattern applicable to a high
wall
entry for a large mining machine. A mining drive is started from a portal 700
at an
exposed face 701 and may follow an approximately circular or oval or similarly
shaped
path such as 702 and exit at another portal 703. The machine can then be
bought out and
overhauled in preparation for the next mining drive. The next drive may begin
at any
desired location and in any desired direction, such as for example, at portal
704 along
path 705 and exiting at portal 706. The advantage of this type of pattern is
no mining
drives overlap and there is no need to excavate through old abandoned access
tunnels.
There may be some of the ore body 707 that cannot mined by this pattern
because of
limitations on the turning radius of the mining machine. This pattern may be
used if the
area 707 contains, for example, lower grade ore or barren ground or a free gas
deposit or
the like. A typical dimension 708 for this pattern is in the range of
approximately 500
meters to 5,000 meters.
In certain situations, the present invention can be used to mine under a low
hill
or heavy overburden area that can occur, for example, within the boundaries of
an
otherwise surface mineable area. In these cases, the mining pattern can
include a series
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CA 02583519 2007-04-20
of adjacent straight runs where the mining machine of the present invention
enters
through a portal on one side of the formation and exits through a portal on
the other side
of the formation. This would allow the mining machine to be turned around
outside the
portals and would avoid the need for the machine to make turns underground. A
similar
mining pattern can be used to mine under large tailings pond complexes or
swampy areas
which overlies economic grade oil sands deposits. Figure 8 illustrates a
possible mining
pattern that can be used to mine under a surface impediment (in general an
obstruction to
surface mining techniques). In such cases, the mining machine could enter at a
portal 800
on one side 801 of the obstruction 802, mine under the obstruction 802 and
exit at a
portal 803 on the opposite side 804 of the obstruction 802. Once the
excavating machine
exits the obstruction 802, it may be turned around by various means and
positioned to
enter another entrance portal 805 preferably not adjacent to the exit portal
803. The
machine then completes its return run exiting at a portal 807. This procedure
eliminates
the need for the mining machine to make any large turns while underground such
as
would occur for example in the mining patterns originating from a single
working face,
other than turns to perhaps avoid zones of barren material or difficult ground
conditions.
The mining pattern of Figure 8 may be implemented by entering and exiting
through any
adjacent tracks or nonadjacent tracks depending on the condition of the
backfill material,
geological, operational or any other considerations. A typical dimension 806
for this
pattern is in the range of approximately about 500 meters to 10,000 meters.
If excavation proceeds from an existing open-pit operation, then an individual
run can start and end at portals located at the surface. New mining operations
in shallow
deposits can also be initiated by excavating a large surface cut to allow the
mining
machines of the present invention to gain access to the ore deposits. For
deposits that are
deeper underground, the machines may have to be assembled underground in a
large
excavated area or cavern, accessed by one or more large shafts or declines.
Once the
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CA 02583519 2008-04-10
underground staging cavern has been completed, machines can be assembled and
be used
to execute an excavation pattern identical to that shown in Figures 6, 7 and 8
with each
run ending in the underground staging area.
Figure 9 shows an end view of an underground staging cavern 900. To construct
the cavern, an access shaft 901 is sunk from the surface to, for example,
through the
overburden 905 and the ore deposit 906 to the bottom 902 of the oil sands
deposit. A
cavern can then constructed at the bottom of the shaft, sufficient in size to
assemble a
mining machine of the present invention. The mining machine can then be used
to form a
full-diameter lined cavity by excavating along an axis or line 903 that
bisects two
sections to be mined. The mining machine may then turn 180 degrees and return
back
along the line adjacent to the outward run. Alternately, a second shaft and
cavern can be
formed and a second machine can be assembled to form the adjacent lined
cavity. When
completed, the parallel, lined cavities can be connected to form a single
large cavern 900
along the boundary of the area to be mined. Once this large cavern 900 is
completed,
mining machines can be assembled and can begin excavating the oil sands
deposits by
forming an entrance portal 904 perpendicular to the staging cavern axis. The
mining
machines can excavate a pattern such as shown in FIGS. 6 and 7, returning to
the cavern
by forming an exit portal also perpendicular to the axis of the staging cavem.
Alternately, the mining machines can excavate by a series of more or less
straight runs
such as shown in Figure 8 where the machines mine from the cavern 900 to a
similar
cavern (not shown) excavated at the other side of the ore body to be mined.
Figure 10 is a plan view of a feasible underground staging area for machines
to
excavate a mining pattern similar to those patterns applicable to a high wall
entry. Here,
a large underground cavern 1000 is constructed along a line that bisects two
sections
1001 and 1002 of oil sands deposits or leases to be mined. The cavern is
connected to the
surface via one or more access shafts 1003 or declines. In this configuration,
the ore
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CA 02583519 2008-04-10
deposits in sections 1001 and 1002 can both be mined from a single cavern
1000. A
typical mining drive trajectory 1004 is shown, although other mining patterns
can be
used.
Figure 11 illustrates how mining patterns can be applied to different levels
of an
underground deposit. Two layers of overburden 1100 and 1101 are shown
overlying an
ore deposit 1102 which, in turn, overlays a basement formation 1103. An
underground
staging cavern 1104 and an access shaft 1105 are shown. Also shown is a
previous level
of mined ore that has been replaced by backfill 1106. To mine out the next
level,
additional earthen or rock material 1107 has been placed on the cavern floor
to provide a
platform for mining drives 1108 carried out by a mining machine 1109 on the
new level.
A small trailing access tunnel 1111 is shown behind the mining machine 1109.
The
method of depositing material to serve as a platform for mining various levels
of an ore
deposit can be used any number of times and can also be applied to mining
various levels
accessed at the surface from a high wall entry.
It is possible to control the positioning of a large TBM with high accuracy,
so it
is also possible to achieve a higher recovery rate by nesting adjacent drives
using a
cylindrical tunnel boring machine adapted for mining. Figure 12 illustrates
the most
efficient system of configuring adjacent mining drives using cylindrical
machines. Figure
12 shows a head-on cross-sectional view of adjacent drives 1200 such as would
be
formed by a cylindrical mining machine. The adjacent drives are nested so as
to
maximize the amount of ore recovered while not excavating previously
backfilled
material. The drives may be made at widely different times in order to allow
the backfill
from each drive to become sufficiently consolidated so that an adjacent drive
can be
made without leaving a large unmined area to act as a retaining wall or
pillar. As an
example, a drive 1201 may be made first. The next drive 1202 may be made
sufficiently
far away from drive 1202 so that the unmined ground will serve as a stable
wall between
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CA 02583519 2007-04-20
these drives. It is also possible to leave an unmined area 1203 to serve as a
retaining wall
between adjacent drives. The timing, location and spacing between adjacent
mining
drives is dictated in large part by the nature of the backfill material. If
the backfill
consolidates quickly with some strength and approximately the same density as
the
unmined ore, then adjacent drives can be made shortly after completing the
neighboring
drive. If the backfill does not consolidate well, the range of spacing 1203
between
adjacent drives may be in the range of approximately 0.25 to 2 diameters 1204.
As will be appreciated, a bitumen separator apparatus in the machine can bring
about bitumen separation by any of several techniques. For example, the
separator can
utilize the Clark process in which caustic is added to an agitated hot water
slurry
(approximately 80 C.) of the oil sands with the bitumen separation completed
by
flotation processes. Other methods eliminate the addition of caustic and use
greater
amounts of mechanical agitation at a lower water temperatures to separate the
bitumen.
Mining Process
The backfilling operations envisioned by the present invention can be carried
out
in a number of ways. In one configuration, the aft most section of the machine
may be
advanced creating a free volume behind the machine and under the large tail
shield. In
this case, previously place backfill may slump into this volume. Thereupon,
backfill
material may be injected or otherwise placed into the volume behind the
advancing
machine. The erection and extension of access tunnel liner segments or
extrusion of a
cast-in-place liner can take place independently of the backfilling process.
The following
drawings illustrate three variants on the method of the present invention.
The following drawings illustrate more details of the mining method and means
of the present invention. Figure 13 shows a side view and a rear view of a
mining
machine typical of the present invention illustrating a large backfill tail
shroud and a
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small access tunnel tail shroud. Figure 13 shows a side view cross-section
1300 and a
rear view cross-section 1301 of a generic mining machine 1302 that is part of
the present
invention. The machine includes a primary ground support shield 1303. The top
portion
of the shield 1304 is called a hood and controls the overburden and protects
the
excavation area. The body of the shield 1303 houses the working mechanisms of
the
machine including the means of excavation 1305 at the front of the machine
1300. The
shield 1303 may be extended past the rear of the machine to form a tail shield
1306
which can protect the rear of the machine during the backfilling operations.
The machine
1300 may also include a substantially smaller (in cross-section) liner tail
shield 1307
which furnishes ground support during the installation process for an access
tunnel liner.
Preferably, the cross-sectional area enclosed by the liner tail shield (in the
plane of the
page) is no more than about 30%, more preferably no more than about 20%, even
more
preferably no more than about 10% and most preferably ranges from about 5% to
about
10% of the cross-sectional area (in the same plane) of the area enclosed by
the large tail
shield (which includes the area enclosed by the liner tail shield). In the
rear view, the
muck discharge ducts 1308 are shown. These ducts 1308 expel backfill material
into the
excavated volume behind the machine as the back section of the machine is
advanced.
Figure 14 shows a sequence of cross-sectional side views of a possible mining
process in which the access liner is formed by adding liner segments and the
backfill is
added at different intervals. In Figure 14a the mining machine 1400 is shown
with a
cutting head 1401 and an internal apparatus 1402 for depositing backfill
material 1403
through a rear bulkhead 1404 into the volume behind the machine 1400. A liner
tail
shield 1405 is shown in which pre-cast tunnel liner segments 1406 are
assembled. In
Figure 14b, the front of the machine 1400 advances pulling the backfill
apparatus 1402
and the liner tail shield 1405 along with it but not far enough to uncover the
last pre-cast
liner segment 1406. The rear of the machine 1400 remains in place along with
the rear
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CA 02583519 2007-04-20
bulkhead 1404. In Figure 14c, the rear of the machine 1400 and the rear
bulkhead 1404
are moved forward, causing some of the backfill material 1403 to slump into
the volume
created by the moving rear bulkhead 1404. During this part of the cycle, two
additional
liner segments 1406 are installed under the liner tail shield 1405. In Figure
14d, the
backfill apparatus 1402 deposits backfill behind the rear bulkhead 1404 to
fill up the
volume behind the machine 1400. The machine 1400 in Figure 14d has advanced
and is
in the same state as in Figure 14a except that two additional liner segments
1406 have
been added. Figure 14e is a repeat of Figure 14b in which the front end 1401
has again
advanced. The liner segments 1406, if used, may be formed from any standard
concrete
based on portland cement or it may utilize other materials such as fly ash,
sawdust or
even mature tailings paste or bitumen to reduce tunnel liner costs.
Figure 15 shows a sequence of cross-sectional side views of the mining process
in which the access liner is formed by adding liner segments and the backfill
is
continuously deposited so as to leave no empty volume behind the machine. In
Figure
15a the mining machine 1500 is shown with a cutting head 1501 and an internal
apparatus 1502 for depositing backfill material 1503 through a rear bulkhead
1504 into
the volume behind the machine 1500. A liner tail shield 1505 is shown in which
pre-cast
tunnel liner segments 1506 are assembled. In Figure 15b, the front of the
machine 1500
advances pulling the backfill apparatus 1502 and the liner tail shield 1505
along with it
but not far enough to uncover the last pre-cast liner segment 1506. The rear
of the
machine 1500 remains in place along with the rear bulkhead 1504. In Figure
15c, the rear
of the machine 1500 and the rear bulkhead 1504 are moved forward while
backfill
material is continuously deposited into the volume immediately behind the
moving rear
bulkhead 1504. During this part of the cycle, two additional liner segments
1506 are
installed under the liner shield 1505. In Figure 15d, the front portion of the
machine
1500 has been advanced and is in the same state as in Figure 15b except that
two
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CA 02583519 2007-04-20
additional liner segments 1506 have been added. This embodiment is preferred
in very
loose and/or unstable ground because it leaves no free volume for any ground
motion to
occur.
Alternately and more preferably, the tunnel liner may be formed by extruding
concrete between two moveable forms to form a tunnel liner. In this
embodiment,
concrete may be mixed in a batch plant near the tunnel portal and slurried
into the
excavation machine, or may be mixed in a batch plant contained in the
excavating
machine. The concrete can then be pumped into the space between the moveable
forms.
The forms are initially located within the mining machine. As the machine
advances, the
forms remain stationary until the concrete has set and then the forms are
withdrawn back
into the machine, leaving the concrete tunnel liner in place with enough
strength to
support the backfill material and any other material that is not supported as
a result of the
excavation process. Figure 16 shows a sequence of cross-sectional side views
of a more
preferred embodiment of the mining process in which the access liner is formed
by
continuously extruding a liner and the backfill is continuously deposited so
as not to
leave any empty volume behind the machine. In Figure 16a the mining machine
1600 is
shown with a cutting head 1601 and an internal apparatus 1602 for depositing
backfill
material 1603 through a rear bulkhead 1604 into the volume behind the machine
1600. A
liner shield 1605 is shown in which the extruded liner 1606 is assembled. The
extruded
liner is formed by an apparatus 1607 contained in the mining machine 1600. The
liner
form 1609 may have strengthening ribs 1608 cast as part of the liner
structure. In Figure
16b, the front of the machine 1600 advances pulling the backfill apparatus
1602, the liner
shield 1605, the liner extrusion apparatus 1607 and the liner form along with
it but not
far enough to uncover the extruded liner portions that have not attained the
level of
strength to support the backfill 1603. The rear of the machine 1600 remains in
place
along with the rear bulkhead 1604. In Figure 16c, the rear of the machine 1600
and the
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CA 02583519 2007-04-20
rear bulkhead 1604 are moved forward while backfill material is continuously
deposited
into the volume immediately behind the moving rear bulkhead 1604. During this
part of
the cycle, the cast-in-place or extruded liner 1606 continues to be formed
under the liner
tail shield 1605. In Figure 16d, the front portion of the machine 1600 has
been advanced
and is in the same state as in Figure 16b except that additional extruded
liner 1606 length
has been added. This embodiment is preferred over the pre-cast liner segment
embodiment because it requires less labor and is more readily automated. The
extruded
liner may be formed from any of a number of fast-setting concretes, for
example, which
utilize accelerants to cause the concrete to achieve a reasonable strength
level in a period
typically of less than a hour.
As will be appreciated, any suitable rotary cutter head design can be employed
for the machine. By way of example, Figure 17 shows front views of various
ways in
which arrays of rotary cutter heads can be arranged to excavate circular or
rectangular
openings. Figure 17a shows a conventional single rotary cutter head 1700 that
might be
used for a cylindrical boring machine used in the present invention to
excavate a circular
opening. The cutter head shown includes three cutting arms 1701. Cutting tools
1702
may be mounted on the cutting arms 1701. The cutting head is rotated about its
axis 1703
in a direction indicated by the arrow 1704. Such a single headed machine will
have a
tendency to roll in the direction of head rotation 1704 which can be
counteracted by
several known means. A machine with a excavating head comprised of an array of
smaller conventional rotary boring heads is illustrated in Figure 17b. Such an
array of
heads 1710 would be mounted in a large frame structure 1711 that forms the
front-end of
a tunnel boring machine and would be capable of excavating an approximately
rectangular opening. As the rotary heads advance through the oil sands
deposits, the
material that passes in the areas 1712 between adjacent heads will be
partially broken
down by the agitation of the rotary head motion, especially if adjacent heads
are rotating
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CA 02583519 2007-04-20
in opposite directions. This material can be further reduced in size
distribution by a
primary crusher located in the machine to reduce the larger rock and sands
accretions to
a size amenable to hydrotransporting. Only the material adjacent to the four
corners 1713
of the machine may be by-passed by this array of boring heads. In the geometry
illustrated, the by-passed material would be about 3% of the total material in
the
rectangular cross-section shown. In contrast, a single large rotary boring
head
1700Figure 17a, would excavate a circular cross-section and would leave behind
much as
22% of the material of the square cross-section because it would not excavate
the areas
outside its circumference. The main bearing required for a rotary head can
seize or
otherwise break down and need to be replaced while a machine is in the process
of a run.
The size of this bearing is about 15 to 20% the size of the rotary head.
Therefore, a spare
bearing stored in the machine would take up considerable space. Alternately, a
replacement bearing would have to be brought in via the trailing access
tunnel. This
would force the construction of an access tunnel having a cross-section of at
least 25 to
35% of the size of the rotary head so that the replacement bearing could be
brought in
past the utility lines. In the case of an array of smaller heads in the array
1710, one or
two replacement bearings could be stored in the machine, taking up far less
space than a
single large bearing. Also the smaller replacement bearings could be brought
into the
machine by a small access tunnel as envisioned in the present invention. The
direction of
rotation of the rotary heads in the array 1710 can be alternated to cancel out
most of the
tendency of the machine 1711 to roll.
Figure 17c illustrates yet other configurations of rotary cutter heads that
can be
used to excavate an approximately rectangular opening and better comminute the
ore.
This machine 1720 has three large cutting heads 1721, 1722 and 1723. The large
center
head 1722 is shown mounted ahead of the two large side cutting heads 1721 and
1723 so
that the cutting cross-sections overlap. Smaller cutting heads 1724 are
mounted in the
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CA 02583519 2007-04-20
spaces between the large cutting heads to help comminute the excavated
material missed
by the large cutter heads. For large machines such as envisioned for the
present
invention, smaller concentric cutter heads 1725 may be mounted coaxially with
the large
cutter heads. These smaller concentric heads 1725 may be rotated counter to
the direction
of the large coaxial heads as shown to assist in preventing excavated material
from
sticking near the center of the primary cutter heads. The three large cutting
heads may be
rotated in opposite directions, as shown, to reduce the roll tendency of the
machine 1720.
The preferred cross-section is rectangular with overall dimensions in the
range of
approximately 7.5 to 30 meters wide by approximately 7.5 to 20 meters high. If
circular
cutting heads are used, the preferred number of heads that comprise the front
end is in
the range of about 2 to 12.
An identified problem of excavating oil sand is mechanical cutter wear due to
the
abrasive nature of the quartz sand grains. Another identified problem is the
difficulty in
handling oil sand material because it tends to become very sticky with working
and re-
working. Working the oil sand material tends to heat it which causes the
bitumen to
become more fluid (less viscous), turning it from a solid or semi-solid
bituminous
substance to very viscous heavy oil. In excavating sandstone or sandy
material, TBMs
often employ a slurry shield or mixed slurry shield type of cutting head to
assist with
stabilization of the excavation face. To implement this technique, water is
injected into
the volume immediately ahead of the cutting head to create a slurry of the
excavated
material. The slurry so formed is often kept at a slightly higher pressure so
as to prevent
voids and cavitation from developing so that the material will flow through
openings in
the cutter head and into the materials handling system. The method can be
extended in
unconsolidated and soft rock media by using high pressure water jets to
excavate the
material. Often, the water jets perform the primary excavation and mechanical
cutter
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CA 02583519 2008-04-10
elements are included to provide backup excavation of any material not fully
broken by
the action of the water jets.
A slurry shield front-end would overcome the two excavation problems
described above. First, the formation of a slurry will substantially reduce
cutter head
wear. Additionally, if water jets are used for the primary excavation, any
mechanical
cutter heads will be subjected to even less wear from the abrasive action of
sand grains.
The formation of a slurry by the addition of ambient temperature water ahead
of the
TBM cutter head also controls the temperature of the excavated material by (1)
diluting
the material with a heat sink material and (2) by substantially reducing
mechanical
working of the material. The excavated oil sand material thus may tend to
remain as
semi-solid substance and not be transformed into a sticky, highly viscous
material that
will clog machinery or adhere to surfaces of the material handling system.
Figure 18a shows a schematic side view of a cutter head assembly comprised of
both mechanical cutter elements and water jet cutter elements. The cutter 1800
head
contains a number of mechanical cutters 1801 and water jet cutters 1802. The
water jet
cutters 1802 are used for primary excavation of the oil sand material 1803 and
also
provide the water to form a slurry 1804 in the volume 1805 between the cutter
head 1800
and the forward shield 1806. The slurry 1804 is transported through the cutter
head 1800
into a pipeline 1807 which feeds the slurry 1804 into a primary crusher 1808.
Figure 18b
illustrates a closed cutter head assembly 1820 also using both water jets 1821
and
mechanical cutters 1822 for excavating the material and forming a slurry. The
isometric
view 1823 shows the water jets and mechanical cutters arrayed on a rotary
cutter head
1824.
Figure 19 shows a rear view of a large excavating machine with two overlapping
rotary cutter heads illustrating the cross section of the trailing access
tunnel and various
other features. Figure 19 shows a rear view of a large binocular excavating
machine 1900
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CA 02583519 2007-04-20
that can excavate a roughly rectangular excavation opening, illustrating the
cross-section
of the trailing access tunnel 1901, the backfill or spoil injection discharge
pipes 1902,
utility lines 1903 and hydrotransport slurry pipelines 1904. Utilities include
electrical
power, water input and output, chemicals necessary for forming a slurry,
sewage
disposal, and the like. A ventilation duct 1905 for incoming ventilation air
is shown. The
outgoing ventilation air in this configuration uses the main tunnel volume
1906. Because
of the small diameter of the access/service tunnel, the design of the
ventilation system
requires special attention. Output ventilation air may have to be compressed
and
discharged under pressure to minimize the diameter of the discharge line.
Input fresh
ventilation air can also be compressed and input under pressure to minimize
its line
diameter. This would require a filtration unit in the excavation machine to
remove any
contaminants (such as oil) that result from the compression and pressurized
pumping
process. The access tunnel is shown with utility lines 1903, slurry transport
lines 1904
and a large ventilation duct 1905 arranged in such a way as to allow a
transport vehicle
1907 to pass through the tunnel 170.
Mining Operations
A mining operation based on the present invention can use large mining
machines either as a stand-alone mining operation or in conjunction with an on-
going
open-pit mining operation. The following figures show examples of some of the
surface
facilities required to support an underground mining operation using large
TBMs that
backfill behind themselves as they advance (the bore & fill method). Figure 20
is an
isometric view looking down on a possible mining operation near a working
portal. A
working porta12001 that supports an underground machine is shown along with an
exit
porta12002 formed by another mining machine 2003 that has recently completed a
drive.
A new entrance portal 2004 under development is also shown along with a mining
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CA 02583519 2007-04-20
machine 2005 which is using a thrust stand 2006 to push off and begin to
advance its
tunnel. Another mining machine 2007 is shown in a TBM mover apparatus 2008.
This
mover 2008 acquires a TBM mining machine at an exit portal after the TBM has
completed a mining pass or drive, transports it into a maintenance shop 2009
for
overhaul, then moves it into position at a newly installed entrance portal so
that the
refurbished mining machine can begin its next mining pass. Some of the
utilities and
other supplies to support an on-going underground TBM mining drive are also
shown.
Oil sand slurry output 2010 shown coming out of the working portal 2001 is
directed to
an area where the bitumen can be extracted by a bitumen separation facility
2011 that
serves a number of portals. The tailings materials left after the bitumen has
been
extracted are shown stored in piles 2012 and small tailings pond facilities
2013, as
required. An small office 2014 building for support personnel is also shown.
Figure 21 shows an isometric view of the portal area of a possible mining
operation using tunnel boring machines entering and exiting at an exposed
working face.
The structure 2101 to support a working portal 2102 is shown installed into
the face of
the ore deposit 2103. The vertical pipe 2104 is the ventilation duct that
services the
working portal 2102. Input and output slurry lines 2105 and the utilities
lines 2106 are
also shown. A second portal structure 2110 is shown with a large mining
machine 2111
and its access tunnel tail shield 2112. The mining machine 2111 is started
into the portal
2110 by thrusting off a fixed thrust frame 2113.
Figure 22 shows an isometric schematic view of a machine that can lift and
turn
a large mining machine of the present invention. The large mover 2201 would
acquire a
mining machine, such as a tunnel boring machine 2202 that had exited a portal
from a
mining drive. The mover 2201 would hold the mining machine 2202 for example
using a
series of slings 2203. The mover 2201 would move, for example, by utilizing
tracks 2204
to move the mining machine 2201 out from an exit portal, move it into a
maintenance
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CA 02583519 2007-04-20
facility for overhaul, and then move it into position in front of an entrance
portal for the
next mining pass. The mover 2201 an be fabricated from, for example,
structural steel
members 2205 and powered by any of a number of means such as compressed air,
hydraulic, electric or internal combustion engines.
Internal Processes
In the present invention, the large shields provide opportunity for many
processes, in addition to excavating and transporting out ore, to be carried
out within the
mining machine. Figure 23 presents a flow chart of the oil sands material as
it passes
through the mining machine for the case where the bitumen is separated from
the oil
sands in an external processing facility. Oil sands material 2301 enters by
the action of
the cutter heads. The excavation may be carried out by forming a slurry at the
working
face in which case a slurry suitable for hydrotransporting may already be
formed. The
excavated material is then fed into a primary crusher 2302 where any large
fragments are
broken down. The oil sands material is then fed to an apparatus where water
and other
chemicals, if necessary, are combined to form a final hydrotransportable
slurry 2303.
The slurry is then hydrotransported 2304 out the access tunnel to an external
bitumen
separation facility where the bitumen is recovered. The bitumen extraction
facility may
be located outside the portal or at a substantial distance from the portal.
Outside of the
scope of the present invention, the bitumen is then sent to a refmery where it
is converted
into crude oil 2305, the final product. Sand, mud and shale material remaining
after the
bitumen separation process is hydrotransported 2306 as needed back to the
machine via
the access tunnel. The returning slurry is fed to an apparatus 2307 where the
bulk of the
water is removed from the material and appropriate binder and stabilizing
agents are
added. The resultant material or spoil is then injected 2308 into the volume
behind the
advancing machine.
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Figure 24 shows a flow chart of the oil sands material as it passes through
the
mining machine for the case where bitumen or heavy oil is separated from the
oil sands
inside the mining machine. Oil sands material 2401 enters by the action of the
cutter
heads. The excavation may be carried out by forming a slurry at the working
face in
which case a slurry suitable for hydrotransporting may already be formed. The
material
is fed into a primary crusher 2402 where any large fragments are broken down.
The oil
sands material is then fed to an apparatus where the bitumen is separated from
the oil
sands 2403. The separated bitumen is then sent to an apparatus in which water
and other
chemicals, if needed, are combined to form a slurry 2404. For example, caustic
may be
added to speed up the separation process as is done in the Clark process.
Since bitumen
separation involves an interplay between mechanical agitation, slurry
temperature and
slurry PH, chemicals other than caustic may prove cost-effective. The slurry
is then
hydrotransported 2405 out the access tunnel to an external refinery where it
is converted
into crude oil 2406, the final product. Back in the machine, the sand, mud and
shale
material remaining after the bitumen separation process is then fed to an
apparatus 2407
where appropriate binder and stabilizing agents are added. The resultant
backfill material
or spoil is then injected 2408 into the volume behind the advancing machine.
Some of
the bitumen is removed before the bulk of the bitumen is formed into a slurry
and is fed
2409 into a compact asphalt cement plant inside the machine. Additional
materials such
as binders and crushed rock are brought in from the outside via the access
tunnel and fed
2410 into the asphalt cement plant. The materials are processed in the asphalt
cement
plant 2411 to form part or all of the tunnel liner segments that will be
installed as the
access tunnel is extended behind the advancing machine.
The present invention is extended to include an internal materials processing
system that is completely isolated from the machine personnel areas. An
example of this
additional capability is illustrated in Figure 25 in which a TBM mining
machine is shown
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CA 02583519 2007-04-20
in side view excavating into a hydrocarbon deposit. The crew area can be
constructed as
a self-contained pressure-resistant volume. Normally the crew area can be open
to the
access tunnel and remain at atmospheric pressure. In the case of an emergency,
however,
the crew area can be closed off and operated using a supply fresh air until
the emergency
conditions are corrected. In the present invention, the emissions from the
excavated ore
and the mining machine are all contained and routed into the isolated ore
transportation
system and not released into the atmosphere. Thus the present invention has
the potential
to contain and dispose of significant methane, carbon monoxide, carbon dioxide
and
other toxic gases. Further, much of the excess heat generated in the mining
machine of
the present invention is used to help separate bitumen from the oil sand,
further reducing
the amount of emissions from the mining, hydrotransport and bitumen separation
processes. The present invention therefore can significantly reduce the total
emissions
associated with the large scale oil sands mining process. Figure 25 shows a
side view of
a TBM mining machine 2500 excavating into a hydrocarbon deposit 2501, in which
the
flow of materials is isolated from the personnel. The material excavated
passes through
the cutter head assembly 2502 into a pressurized chamber 2503 in which the
material is
fed down a muck chute 2504 into the primary crusher 2505. The excavated
material may
or may not be in slurry form depending on the mode of cutting. The material
moves from
the primary crusher 2505 through a closed pipeline 2506 into a materials
processing
chamber 2507. The materials processing chamber 2507 may separate the desired
material
(for example bitumen) and form a slurry of the desired material for
hydrotransporting out
the access tunnel 2508 via an outgoing slurry pipeline 2509. Concurrently, the
remaining
separated material or spoil is sent via a slurry pipeline 2510 and injected or
returned into
the formation at the muck or spoil discharge point 2511 behind the advancing
machine.
Alternately, excavated material may be formed into a slurry inside the cutting
head 2502 or the processing chamber 2507 and hydrotransported out the access
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tunnel 2508 via the outgoing slurry pipeline 2509. In this case, the desired
material
(for example bitumen) is separated above ground in an external facility and
backfill
or spoil material is hydrotransported back to the machine via an in-coming
slurry
pipeline 2512 to the processing chamber 2507. The material is then prepared as
needed and sent via a pipeline 2510 to be injected into the formation at the
muck or
spoil discharge point 2511 behind the advancing machine.
The out-going pipeline 2509 and in-coming pipeline 2512 may also be used to
add or subtract small amounts to the spoil material to be injected back into
the
formation in order to ensure that the proper volume of material is injected to
exactly
fill the volume behind the advancing machine. This may be necessary since a
desired
product material is removed from the excavated material and the spoil may be
compacted by the thrust of the advancing machine.
The pressurized chamber 2503 is at a pressure slightly higher than ambient
formation pressure in order to exclude unwanted vapors and fluids. The
excavated
material is brought into the machine by the mechanical action of devices such
as for
example, a screw auger or directly as a slurry if the machine 2500 is operated
in a
slurry or earth pressure balance mode. The formation pressures can typically
range
from atmospheric pressure to pressures up to about 20 or more atmospheres. The
pressure in the pressurized chamber 2503 is preferably about 0.1 to 3
atmospheres
higher than formation pressure. The pressure in the areas 2513 where operators
and
personnel are stationed is typically atmospheric since this portion of the
machine is
connected to the outside world by the trailing access tunnel 2508.
The crew area 2513 is separated from the pressurized chamber 2503 by a
pressure bulkhead 2514. The muck discharge pipeline 2510 and the trailing
access
tunnel liner 2515 both pass through another pressure bulkhead 2516. The access
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tunnel liner 2515 has a sliding seal mechanism to allow the liner to be
assembled
within the machine and to be left behind as the machine excavates and
advances.
Also shown is a control room 2517 normally connected to the total working area
can
serve as an emergency self-contained personnel haven. The self-contained
control/personnel room 2517 is connected to the main working area 2513 for
example
by a stairwell 2518 or some other access means. Under normal operating
conditions
the work area 2513, the access tunnel 2508 and the control/personnel room 2517
and
connecting stairwell 2518 are all open and on the same air supply. In an
emergency
situation such as a breach in the materials handling system or in the tunnel
liner 2515,
the personnel can be sequestered in the control/personnel room 2517 and the
access
stairwel12518 can be closed off by a pressure door. The air in the
control/personnel
room 2517 can be supplied by a self-contained air supply such as provided for
example by a number of compressed air bottles. The self-contained
control/personnel
room 2517 is preferably large enough to hold from 10 15 persons for a period
of up
to 6 days.
Figure 26 shows a side schematic view of a TBM mining machine
configuration illustrating the volumes occupied by both outgoing oil sand or
bitumen
slurry and incoming tailings slurry and other features. The slurry 2600 is
formed in
the volume 2601 between the cutter head 2602 and the forward portion of the
main
shield 2603 either by water injected into the volume 2601 or by water from the
water
jet cutters 2604 or from both water jet cutters 2604 and other water injection
ports.
The slurry 2600 passes through the cutter head 2602, down a pipeline 2605 to a
primary crusher 2606, down a pipeline 2607, through a flow monitoring station
2608
and into a processing/switching apparatus 2609 and out a hydrotransport
pipeline
2610. A return hydrotransport pipeline 2611 contains a slurry of processed
material
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which is fed into the processing/switching apparatus 2609 where it is de-
watered and
prepared for injection as backfill into the volume 2612 behind the advancing
machine. The processing/switching apparatus 2609 contains an internal
apparatus that
includes but is not limited to a de-watering apparatus for de-watering the
returning
processed sands; an internal apparatus for preparing the de-watered sand for
injection
as backfill; an internal apparatus for separating bitumen from oil sand; and
an internal
apparatus for diverting the slurry from the primary crusher directly to the de-
watering
apparatus for de-watering the returning processed sands.
The oil sands deposits can be highly variable in ore grade both through the
thickness of the deposit and over the areal extent of the deposit. It is also
possible to
encounter barren water-saturated sands or sands containing a significant
fraction of
shale, clay and/or mudstone stringers. An extension of the present invention
is the
addition of an apparatus 2608 to determine the approximate grade of the ore
after it
passes out of the primary crusher of the mining machine. If the grade of the
ore is too
low for transporting to the portal, then the slurried ore can be directed to a
de-
watering plant contained in apparatus 2609 in the machine and injected into
the
volume 2612 behind the advancing machine. In the case where the machine
contains
a bitumen separation plant in apparatus 2609, the low grade ore or barren
material
can be diverted to the de-watering plant in the machine and injected into the
volume
2609 behind the advancing machine.
If the excavated ore is in the form of a slurry, it can be passed through an
apparatus 2608 where various diagnostics may be used to determine the average
grade of the ore. The ore grade is usually expressed as a percent by mass of
bitumen
in the oil sand. Typical acceptable ore grades for oil sand is about 6% to 9%
by mass
bitumen (lean); 10% to 11% (average) and 12% to 15% (rich). A typical oil sand
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slurry is comprised of water (about 25% to 50% by mass) with the rest being
oil sand.
Typical slurry flow velocities are in the range of about 2 to 5 meters per
second.
The slurry flowing through a diagnostic pipeline section 2608 involves the
material to be diagnosed flowing past the diagnostics. This is basically the
reverse
situation as in conventional well logging where a diagnostic sonde is pulled
up
through the material to be measured. The relative motions, however, are the
same.
Thus, conventional well-logging diagnostics can be applied to determine the
water/hydrocarbon ratio of the slurry. For example, induction, resistivity,
acoustic,
density, neutron and nuclear magnetic resonance (NMR) diagnostics can be used
to
provide the data required to solve Archies equation in the same way as done in
conventional well logging practice.
Another potential method for determining ore grade is by the use of Near
Infra Red (NIR) technology which is based on the observation that bitumen
content
varies inversely with fine clay content. In particular, diffuse reflectance
NIR
spectroscopy using a fibre optic probe has the capability of measuring oil
sand ore
grade to within acceptable limits for the typical range of oil sand slurries
and oil sand
ore grades. This technology has been successfully demonstrated in the
laboratory and
can be adapted as an ore grade diagnostic for the present invention. The
technique for
determining ore grade accuracy should have a resolution of less than about 1%
and
more preferably less than about 0.5% by mass of bitumen in the ore. Once the
ore
grade is established, it is possible to divert below-grade oil sand slurry
directly to a
de-watering system and then into the backfill volume 2612 behind the advancing
mining machine. This eliminates the need to send below-grade ore or barren
material
to the bitumen separation plant and allows the present invention to provide
oil sand
ore within specified limits to the separation plant.
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It is possible to totally isolate the atmosphere in a TBM mining machine so
that it can operate at greater depths and under greater formation pressures.
In this
mode, a pressure air-lock system 2613 would be required at some point in the
trailing
access tunnel. In this embodiment, the formation surrounding the mining
machine
2514 has a characteristic formation pressure p 1. The air at the surface has
an
atmospheric pressure p2. If the formation pressure p 1 is much greater than
the
atmospheric pressure p3, then it may be desirable to maintain the pressure p2
in the
personnel areas of the mining machine at some intermediate pressure p2, where
pl>p2>p3. This can be accomplished by establishing an air-lock entry system
2613
somewhere in the access tunnel 2615 between the mining machine and the portal
to
the surface. The pressure on the portal side of the air-lock entry system 2613
is at the
same pressure as the outside atmosphere which is at p3. Once the air-lock
entry
system 2613 is installed, it can be used to control pressure p2 such that the
difference
between the local formation pressure p 1 and the interior pressure p2 in the
mining
machine 2614 is maintained within the safe design limits of the structural
members
and shield skin of the mining machine 2614.
The propulsion motors, hydraulic cylinders and other power generating
sources in the machine generate large amounts of excess heat energy which must
be
removed via the return ventilation, water and/or slurry systems. In general, a
TBM
type machine produces heat from its propulsion motors, its hydraulic motors
and
hydraulic cylinders and by the action of mechanical cutter tools, if used.
This heat
can be utilized for various functions in the present invention. For example,
the heat
generated from the propulsion motors, hydraulic motors and cylinders and by
the
action of mechanical cutter tools can be transferred to water or some other
appropriate fluid via a heat exchanger apparatus. The water is then available,
for
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example, to be flushed into the area of the cutter head or muck chamber to
help form
a slurry suitable for hydrotransport. This warm of hot water can also be used
to form
water jets to help excavate the material and can be used to begin the
separation of the
bitumen from the sand as the material is being excavated. The waste heat can
also be
used to elevate the temperature of other materials such as for example a
slurry in an
internal bitumen separation facility, and the concrete, asphalt or grout in an
internal
access tunnel liner extrusion facility and the slurry in a de-watering
facility used to
de-water a tailings slurry used for backfill. Since the present invention
operates
underground, the waste heat can be captured and used for other purposes. This
is an
important energy efficiency advantage over open-pit excavation machines such
as
shovels and trucks whose waste heat is usually lost in the atmosphere.
Figure 27 shows a preferred embodiment of a heat exchange system to utilize
waste heat for heating a slurry at the working face. Waste heat is generated
primarily
by the action of hydraulic thrust and extension cylinders 2701 and by electric
motors
2702 used for various purposes including thrusting and rotating the cutting
head.
These cylinders and motors may be cooled by a suitable coolant such as water
that is
pumped through a closed circuit. A pump 2703 pumps coolant into a circuit 2704
which passes through the cylinders 2701 and motors 2702 where it becomes
heated.
The heated coolant passes through a heat exchanger 2705 where the coolant
gives up
its excess heat to water in a separate circuit 2706. This water may originate
in an
outside source and come in via a pipeline 2709. The water, after passing
through the
heat exchanger 2705, is injected into the cutting head slurry 2707 (and/or
muck
chamber and/or water jets and/or bitumen separator and/or internal access
tunnel liner
and/or de-watering facility). Additional water from another source 2710 may be
added to the slurry 2707 to achieve the required slurry conditions. This
additional
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water may also be heated by a separate source (not shown). The slurry formed
from
water and excavated ore eventually makes its way out of the excavation area
via a
hydrotransport pipeline 2708.
A simple tunnel boring machine may advance by increments. In the case of a
machine comprised of two sections, the front end of the machine advances
during its
cutting cycle while the rear section remains stationary. Then the advance of
the front
end is stopped while the rear end is moved forward by the use of grippers or
other
propulsion means. A double shield tunnel boring machine can overcome this
incremental advance by allowing the front end and rear ends to be moved
independently and simultaneously. Even these machines must stop their advance
for
periodic maintenance or to overcome an equipment breakdown or unanticipated
change in ground conditions. Thus, it is important for a tunnel boring type
machine
used for mining purposes to have some form of ore surge control to allow a
more or
less even flow of ore from the machine out to the portal of the access tunnel.
It is also
important to have some form of surge control for both outgoing oil sand (or
bitumen)
slurry lines and incoming tailings slurry lines because it is difficult to
stop and restart
the flow of high density slurries in long hydrotransport lines. The surge
chambers
should be large enough to accommodate in the range of 0.5 to 4 hours of
average
production of the mining machine.
Possible locations for slurry surge control are illustrated in Figure 28.
Figure
28a shows possible locations of surge control chambers for the flow of ore
slurry
from the mining machine 2800 through the access tunnel 2801, out the working
portal
2802 to the surface area 2803. The slurry is formed in the cutter head 2804 or
the
adjacent muck chamber 2805 and sent via a pipeline 2806 to a surge chamber
2807
which is contained within the mining machine 2800. The surge chamber 2807
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provides flow control of ore slurry while the pipeline 2808 behind the surge
chamber
2807 is extended from time to time. The ore slurry moves down the access
tunnel
2801 via a long hydrotransport line 2809, out the portal 2802 and into a
second surge
chamber 2810. The function of surge chamber 2810 is to control the flow of ore
slurry from the mining machine operation to the main ore hydrotransport system
of
the overall oil sands mining operation. The flow of ore slurry may be diverted
from
the surge chamber 2807 directly into the backfill system of the machine, for
example,
if the ore grade is too low or the excavated ground is barren. The backfill
system may
be comprised of, for example, a de-watering facility 2814 coupled to a
backfill
pumping system 2815 which distributes backfill tailings material into the area
behind
the advancing mining machine 2800. Figure 28b shows possible locations of
slurry
surge control chambers for the flow of tailings slurry from the surface area
2803 into
the working porta12802, through the access tunne12801 to the mining machine
2800.
The tailings slurry is generated outside the access tunnel 2801 possibly at a
distant
bitumen separation plant or at a smaller tailings slurry facility located near
the
working portal 2802. The surge chamber 2811 controls the flow of tailings
slurry
from the main tailings slurry system of the mine to the tailings slurry
pipeline 2812 in
the access tunnel 2801. The tailings slurry enters a second surge chamber 2813
located in the mining machine 2800. The purpose of the second surge chamber
2813
is to control the flow of tailings slurry to the backfill system. The backfill
system
includes, for example, a de-watering facility 2814 coupled to a backfill
pumping
system 2815 which distributes tailings material into the area behind the
advancing
mining machine 2800.
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Propulsion and Steering
As will be appreciated, modern tunnel boring machines can be propelled by a
variety of means including thrusting off the tunnel liner erected behind the
machine,
by soft-ground gripper pads that can be thrust out against the walls of the
excavation
or by a combination of both methods. These methods allow a forward shield
segment
to advance relative to a rear shield segment, usually by an array of internal
hydraulic
cylinders that can extend or retract the segments relative to each other. The
diameter
of the main shields of most soft ground machines are short compared their
length and
the above means of propulsion are adequate. In the present invention, the
tunnel liner
is much smaller in cross-section than the main shield and the machines tend to
be
longer relative to their diameters because the machines often contain
additional
equipment such as, for example, a bitumen separator, a backfill de-watering
and
injection apparatus. The machines envisioned in the present invention can use
large
area soft-ground grippers for propulsion and can also thrust off the backfill
material
injected behind the machine. The following describes yet another means of
propulsion suitable for a longer machine.
Figure 29 shows a side view of a sequence of machine motions for a large
segmented excavating machine that advances by utilizing differential friction
as a
means of propulsion. In one embodiment, the above method is implemented by a
large multi-segmented boring machine apparatus. The segmentation allows the
machine to change direction efficiently and allows the machine to follow the
meandering oil sands deposits. The segmentation also permits the machine to
advance, one segment at a time, by the moving segment thrasting against the
combined static friction of the stationary segments. The sequence of motions
to
advance the segmented machine for the present invention is shown in Figure 29.
The
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initial position of the machine is shown in Figure 29a and the distance
through which
the machine will advance in one full cycle of movement is shown by 2900. The
start
of a new advance cycle is shown in Figure 29b. The forward most segment 2901
moves forward, pushed by the hydraulic jack cylinders connecting the forward
most
segment 2901 with the second segment 2902. The forward most segment 2901
contains the excavating head 2903 and the oil sand is excavated only during
the
movement 2915 of this forward most segment. Once these cylinders are fully
extended, the second segment moves as shown in Figure 29c. The second segment
2902 is advanced by the hydraulic jack cylinders connecting the forward most
segment 2901 with the second segment 2902 retracting and the hydraulic jack
cylinders connecting the second segment 2902 with the third segment 2903
simultaneously extending. Each subsequent segment advances in turn in a like
manner as shown in FIGS. 29d through 29h. Finally, as shown in Figure 29i, the
aft
most segment 2908 moves forward, pulled by the hydraulic jack cylinders
connecting
the aft most segment 2908 with second to last segment 2907. As the aft most
segment
2908 advances, spoil is injected into the volume 2914 behind the machine
created by
the motion of the aft most segment 2908. The distance 2980 through which the
rear
end of the machine has advanced in one full cycle of movement in the direction
indicated by arrow 2915 is the same as that of the front end shown by 2900.
Now the
machine has completed one cycle of motion and has advanced a distance 2900 at
an
average advance rate of the instantaneous advance rate of each segment divided
by
the number of segments.
Figure 30 shows various alternate means for a TBM mining machine to
propel and steer itself. Figure 30a shows a mining machine in a straight, non-
turning
position. The cutter head 3001, the forward segment 3002, the rear segment
3003, the
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backfill thrust plate 3004, the backfill tail shield 3005 and the access
tunnel tail
shield 3005 are all shown in-line along the same axis. The direction of motion
of the
mining machine is indicated by the arrow 3007. Figure 30b shows the various
means
by which a mining TBM can turn. The turn can be to the left, to the right,
upwards or
downwards or any combination thereof. Also any of the means of tu.rning may be
applied in any combination to achieve a desired machine positional control and
steering. The cutter head 3001 can be articulated with respect to the forward
segment
3002 to turn in the direction indicated by arrow 3008. The forward segment
3002
may be articulated with respect to the rear segment 3003 by, for example,
differentially extending its connecting hydraulic cylinders to turn in the
direction
indicated by arrow 3008. A hydraulically or otherwise actuated drag plate 3009
may
be deployed to cause additional drag which will cause the machine to turn in
the
direction indicated by arrow 3008. The backfill tail shield 3005 is attached
to the rear
segment 3003 and so follows the motion of the rear segment 3003. The backfill
thrust
plate 3004 may be articulated with respect to the rear segment 3003 to turn in
the
direction indicated by arrow 3008. The access tunnel tail shield 3006 is
attached to
the backfill thrust plate 3004 and so follows the motion of the backfill
thrust plate
3004. The cutter tools (not shown in this view) mounted on the cutter head
3001 may
be retracted, extended and oriented by hydraulic actuators to also affect the
cutting
forces applied to the excavated face. This action can also be used alone or in
combination with any of the aforementioned methods to achieve a desired
machine
positional control and steering. As will be appreciated, drag plates can be
located on
the right side of the machine to facilitate right turns, on the left side of
the machine to
facilitate left turns, on the bottom of the machine to facilitate downward
turns, and/or
on the top of the machine to facilitate upward turns. A drag plate, as its
name implies,
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contacts a wall of the excavation and the resulting frictional force causes
the
advancement of the machine side on which the drag plate is located to be
slower than
the opposite side of the machine on which the drag plate is absent or is in
the
retracted position. The drag plates may be hinged to rotate outwardly (the
deployed
position) and inwardly (the retracted position), or the drag plates may be
hydraulically extended and retracted without hinging.
Figure 31 shows an isometric view of a possible the hydraulic cylinder
arrangement for propulsion and steering of a basic segmented machine with two
rotary cutter heads 3101 and 3102. This binocular TBM can mine a roughly
rectangular cross-section. Figure 31 highlights the arrays of retracted
hydraulic push
jack cylinders 3103 and extended cylinders 3104 that provide the propulsion
and
steering capability for the machine. In the embodiment shown in Figure 31, the
segments of the machine are all connected to form a single skeletal structure
by the
arrays of cylinders which are attached to thrust plates 3105 as shown. The
machine
shown has dual trailing access tunnel tail shields 3106 and 3107. This machine
configuration is capable of erecting dual access tunnel liners, one of which
may
contain all input utilities and material pipelines and the other output
utilities and
material pipelines. In addition, the dual tunnels themselves may serve as
input and
output ventilation ducts. Dual tunnels also provide safe egress in the event
that one of
the tunnels collapses.
Figure 32 shows an example of a single segmented TBM mining machine.
The machine 3200 is formed from a single large shield 3201, an articulated
cutter
head 3202 and an access tunnel tail shield 3203. A typical diameter 3204 for
the main
shield 3201 and cutter head 3202 is in the range of approximately 10 meters to
20
meters. A typical dimension 3205 for the access tunnel tail shield 3205 is in
the range
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of approximately 2.5 meters to 4 meters. The machine 3200 can be propelled by
thrusting off the backfill material. The machine 3200 can be steered by any
combination of means such as (1) the cutter head 3202 articulating with
respect to the
main shield 3201; (2) the backfill thrust plate (not shown) articulating with
respect to
the main shield 3201; (3) deploying one or more a drag plates (not shown) from
the
main shield 3201; and (4) retracting, extending and/or orienting the cutter
tools 3206
on the cutter head 3202.
Figure 33 shows a turning sequence that might be used to execute a turn
required by one of several possible mining patterns or to avoid barren ground
or to
navigate around an obstacle. The turn may be executed in any orientation in
space
(right, left, up, down etcetera). The desired path of excavation is shown by
the track
3301. In Figure 33a, the mining machine 3302 is shown entering the turn, using
several means to cause the cutter head 3303, the forward segment 3304 and the
rear
segment 3305 to turn in the desired direction. The axis 3306 of the access
tunnel tail
shield 3307 remains aligned with the desired track 3301. Figure 33b shows the
machine 3302 in the middle of the desired turn. Figure 33c shows the machine
3302
near the end of the desired turn. All through the turn, the axis 3306 of the
access
tunnel tail shield 3307 remains aligned with the desired track 3301. As will
be
appreciated, the right turn is the mirror image of the left turn.
Access Tunnel Liners
An important feature of the present invention is an access tunnel that has a
substantially smaller cross-sectional area than the cross-sectional area of
the main
excavation. There are several means to form the access tunnel, including
erecting pre-
cast liner segments, extruding the liner or allowing the liner to be formed by
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consolidated backfill material formed around a temporary form. The preferred
embodiment is an extruded liner.
Figure 34 shows an apparatus for forming an extruded access tunnel liner and
also shows a side view of soft-ground grippers. Figure 34a shows a side view
of a
mining machine 3400 which shows a concrete batch mixing plant 3401 and an
apparatus 3402 for extruding concrete into a liner form 3403. The mixing plant
3401,
the extruding apparatus 3402 and the end of the liner form 3403 are all
contained
inside the mining machine 3400 behind the backfill thrust plate 3405. Figure
34b is
an isometric view of the same machine 3400 showing the mixing plant 3401, the
extruding apparatus 3402, the liner form 3403 and the backfill thrust plate
3405. Also
shown in this view is a gripper plate 3406 and its associated hydraulic
cylinders
3407. The gripper plate 3406 is moved in and out to contact the wall of the
excavation, when needed, by the cylinders 3407 thrusting off a thrust plate
3408
which is rigidly connected to the mining machine 3400. Figure 34c shows an
isometric view of the liner form 3403. The liner form 3403 is comprised, for
example, of an outer slip form shell 3413 and an inner slip form shell 3409.
The inner
shell 3409 also may include strengthening ribs 3410. The concrete or other
suitable
liner material is extruded into the space 3411 between the outer shell 3413
and the
inner shell 3409. As the mining machine 3400 advances forward, the liner form
3403
advance with the machine 3400, leaving behind a shell of extruded liner
material.
Figure 34d is a cross-section view that shows the gripper plate 3406, the
gripper plate
extension/retraction cylinders 3407 and the fixed gripper thrust member 3408.
The
inward and outward motion of the gripper plate is illustrated by the two way
arrow
3412.
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As noted above, the access tunnel liner may be formed by extruding concrete
or some other suitable liner material between moveable forms. It then becomes
possible to fabricate the forms such that slurry pipelines and other utilities
conduits
are formed into the liner. This would eliminate the need for separate slurry
pipelines
and other utilities pipelines and ducts. Figure 35 shows an isometric view of
a
possible extruded access liner which contains pipelines and other ducts and
conduits
within the liner material. A possible extruded concrete access liner 3510
which
contains an outgoing ore slurry pipeline 3511 and an incoming tailings slurry
pipeline
3512 formed into the extruded liner material 3513 within the bottom portion or
invert
3514 of the liner 3510. A ventilation duct 3515 is shown formed into the top
portion
or crown 3516 of the liner 3510. The floor 3517 of the tunnel liner 3510 is
preferably
flat to allow transport vehicles to pass in and out of the access tunnel.
There may be situations where dual access tunnels are required for safety
and/or regulatory reasons. In addition, it may be advantageous to have dual
access
tunnels for ventilation and utilities. For example, one tunnel can be used for
in-going
ventilation and slurries and the second tunnel for outgoing ventilation and
slurries.
Figure 36 shows several views of a multi-segmented binocular type TBM with
dual
trailing access tunnels. Figure 36a shows a side view illustrating the cutter
head 3601,
several shield segments 3602 and an access tunnel tail shield 3603. Figure 36b
shows
a plan view of the machine showing the two main TBM cylinders 3604 and 3605
and
the dual access tail shields 3606 and 3607. One of the segments 3608 is shown
in a
retracted state while the other segments are shown fully extended. Figure 36c
is an
isometric view of the mining machine and shows the two cutter heads 3609 and
3610.
Figure 36d shows a cross-section rear view and illustrates two backfill ducts
3611
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and 3612 as well as two access tunnel liners 3613 and 3614 with their included
utilities which were described elsewhere.
In many mining operations accessed by adits or tunnels, two or more adits
may be required for personnel safety and exit. In a typical mining pattern
envisioned
in the present invention, a series of horseshoe tunnels, for example, may be
driven
with each successive tunnel adjacent to the previous tunnel. The first tunnel
drive in a
pattern will have only one exit during installation. Each successive TBM drive
will
leave an access tunnel that can be connected to neighboring abandoned access
tunnels
by a small diameter, lined drift so that personnel can get from one access
tunnel to
the next, thereby providing the required multiple exits. Figure 37 shows a
plan view
of access tunnels in a formation with cross-connecting tunnels to provide
entry to
neighboring tunnels to assist in emergency escape. Figure 37 illustrates two
completed access tunnels 3700 and 3701. One tunne13702 is in the process of
being
excavated by a mining machine 3704 which is advancing in the direction
indicated by
arrow 3705. The tunnels are offset because the cross-section of the area mined
is
much larger than the cross-sectional area of the trailing access tunnels. A
number of
cross-connections 3703 are shown connecting the completed tunnels. The
uncompleted tunnel 3702 is shown connected in three locations to the
previously
installed access tunnel. The interconnections can also be equipped with air-
tight
doors or hatches so that tunnels can be isolated from other tunnels that may
have
unsafe levels of toxic gases.
Alternate Cutter Heads
In certain geologic environments, the front-end of the mining machine of the
present invention can be comprised of an array of shovel, picks and ripper
tool heads
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such as shown for example in Figure 38. This open-face approach has the
advantage
of being flexible for excavating variable geology and for maintenance,
servicing and
overhauling. Figure 38a shows an isometric view of the front end of mining
machine
3801 that uses a hydraulically actuated shovel/scoop 3802 for excavating in
relatively
soft rock or soil. A typical diameter 3803 for the machine 3801 is in the
range of
approximately 5 meters to 15 meters. Figure 38b shows a possible hydraulically
actuated backhoe 3804 that can dig and muck most compacted oil sands material.
A
hydraulic hammer/pick attachment 3805 can be mounted on the back of the
backhoe
assembly 3806 and can be used in harder ground. For example, the hammer/pick
3805 can chip at mud/shale inclusions or compacted oil sand accretions that
cannot
be broken up by the backhoe. The straight pick 3807 shown in Figure 38b can be
replaced by a hooked pick so that the hydraulic arm can also function as a
ripper.
Figure 39 shows an isometric view of a large multi-segmented excavating
machine with two triangular cutter heads that can excavate a roughly
rectangular
excavation opening and leave a small trailing access tunnel. The machine 3901
is
comprised of two Reuleaux triangle cutting heads 3902 which allow the machine
to
excavate and mine a rectangular cross-section. The machine is shown in a
segmented
embodiment with the 3ra segment 3903 from the front fully contracted and the
4th
segment 3904 from the front fully extended. The smaller cross-section trailing
access
tunnel tail shield 3905 is shown extending from the rear of the advancing
machine
3901. The triangular cutting heads have slightly convex sides 3906. Head
rotation
occurs in two kinds of motion. The first is a pure rotary motion of the head
about its
own shaft. The second is a circular motion of the entire cutting head and its
shaft
about an offset center line. This head geometry and eccentric drive system has
been
used in coal mining to form a square rather than a circular opening in order
to extract
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a greater fraction of the coal in the coal seams. The heads rotate in opposite
directions as indicated to substantially reduce the tendency of the machine to
roll.
It is also possible to utilize a single backwards tilted rotary excavation
head
that can excavate a roughly rectangular excavation opening. Such a concept is
described in U.S. Pat. No. 4,486,050.
Utilities Extension
In the present invention, the preferred mode of operation is to form an ore or
bitumen slurry at or near the working face and hydrotransport the slurry out
of the
tunnel, while at the same time hydrotransporting a tailings slurry from the
outside
into the machine for backfill. It is preferable to maintain a relatively
constant flow of
slurry because of the increased difficulties of stopping and starting high-
volume,
relatively dense slurries. A preferred means to extend slurry lines is by the
use of
telescoping sections of pipeline as illustrated in Figure 40. For example, in
case of an
outgoing oil sand slurry, a slurry may be formed in the cutter head or in muck
chamber which is connected to a large surge tank by a fixed pipeline. The
surge
chamber is attached to the last fixed pipe section in the access tunnel by a
series of
specially designed telescoping pipe sections. As the mining machine advances,
one of
the telescoping sections extends until fully extended. Then the next section
extends
and so on until all or nearly all the sections are fully extended.
An example of a telescoping slurry pipeline section is shown in Figure 40.
Figure 40a shows the end 4000 of a section 4001 of telescoping pipeline in
retracted
position. The inner segment 4002 is slightly smaller in diameter than the
outer
segment 4004. The inner surface 4005 of the outer segment 4004 is sealed
against the
outer surface 4006 of the inner segment 4002 by a circumferential wiper made
from
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rubber or some other soft sealing gasket material. This sealing technique is
similar to
that commonly used to seal the bore and cylinder surfaces of a hydraulic
cylinder.
Each end of the telescoping pipe section has a bolted flange system 4007 or
other
suitable connection system for attaching adjacent sections together. Figure
40a also
shows a flexible end coupling 4003. The telescoping pipeline can therefore
bend at
joint 4003 when joined to an adjacent section of pipeline. Figure 40b shows 14
sections of collapsed (retracted) telescoping pipe 4009 beside the same 14
sections
4010 fully or nearly fully extended such that the length of the extended
sections 4010
is nearly twice the length of the fully retracted sections 4009. Figure 40c
shows a
close-up of a fully or nearly fully extended section of telescoping slurry
pipeline
4015. The seal between the inner segment 4016 and the outer segment 4017 is
not
shown but is located between the segments at the approximate location shown by
4018. The wiper seal would be attached to the inner segment 4016 and move with
the
inner segment 4016 while forming a seal against the inner surface of the outer
segment 4017 by moving along the inner surface of the outer segment. Flexible
flanged joints 4020 and 4021 are also shown in this view. The range of
preferred
lengths of telescoping sections in fully retracted position is approximately 2
meters to
6 meters. When fully extended, the range of preferred lengths of telescoping
sections
is about 4 to 12 meters. Typically, 10 to 20 sections of telescoping sections
would be
used in the present invention which would allow the telescoping pipeline to
extend a
distance of approximately about 50 to 100 meters before stopping to retract
the
telescoping pipeline.
Another possible means to extend slurry lines at appropriate intervals is
illustrated in Figure 41. Here a slurry is formed in the cutter head or in
muck chamber
which is connected to a large surge tank by a fixed pipeline. The surge
chamber is
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initially attached to the fixed pipeline in the access tunnel by a flexible
slurry
pipeline section which connects to a Y or T joint at the end of the last fixed
pipe
section in the access tunnel. As the mining machine advances, the flexible
pipeline
section is extended until there is enough space to attach a new section of
fixed
pipeline. Once the new section of fixed pipeline is installed, valves switch
the flow of
slurry from the flexible line to the newly installed fixed pipeline section. A
valve in
the surge tank switches the flow into the flexible line off while nearly
simultaneously
switching the flow into the newly installed fixed section of pipeline. This
method
may be employed whether there is or is not a routine maintenance shutdown at
regular intervals. In Figure 41 a, a cutter head/muck chamber 4100 produces a
slurry
mixture which is fed via a fixed pipeline section 4101 to a slurry surge
chamber
4102. The cutter head/muck chamber 4100, the fixed pipeline section 4101 and
the
surge chamber 4102 are contained within the forward-most section of the TBM
mining machine (not shown). In Figure 41a, the slurry is shown flowing from
the
surge chamber 4102 through a flexible pipeline section 4103 into a long series
of
connected fixed pipeline sections 4104 which have been previously installed
and are
now located in the trailing access tunnel 4105. A switch valve 4106 has
switched the
flow of slurry from the surge chamber exit valve 4107 to the surge chamber
exit
valve 4108. In Figure 41 a, the connection 4109 is broken so that the front
section of
the TBM mining machine can advance while the access tunnel 4105 remains
stationary. Figure 41b shows the front section of the mining TBM advanced such
that
the flexible pipeline section 4103 is fully or nearly fully extended. The
slurry flows
from the exit valve 4108 of the surge chamber 4102 through the flexible
pipeline
section 4103 into the switch valve 4106 and then into the long series of
connected
fixed pipeline sections 4104. As shown in Figure 41 c, a new section of fixed
pipeline
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4110 is installed to connect the exit valve 4107 to a new switch valve 4111.
As
shown further in Figure 30d, the access tunne14105 is extended, the slurry is
diverted
from exit valve 4108 of the surge chamber 4102 to exit valve 4107 of the surge
chamber 4102 so that there is no flow through the flexible section 4103. The
downstream end of the flexible section 4103 is now connected to the new switch
valve 4111 at the upstream end of the newly installed fixed section 4110. At
this
time, the slurry can be diverted from the exit valve 4107 of the surge chamber
to the
exit valve 4108 of the surge chamber so that there is again slurry flow
through the
flexible section 4103. Once the connection 4112 is broken, the situation is
returned to
that depicted in Figure 41 a and the process of moving the cutterhead/muck
chamber
4100 can be repeated.
Use of Access Tunnels
The machine described in the present invention leaves behind a lined access
tunnel. When the machine excavates hydrocarbon deposits, it often encounters
gas
either in the form of free gas contained in structural pockets or in the form
of bound
gas dissolved in the formation water and hydrocarbon material. When the
excavated
volume is exposed to significantly lower pressure such as atmospheric
pressure, the
dissolved gas will begin to come out of solution and flow towards the
excavation.
The flow rate will be limited by the local permeability. One of the major
features of
the invention described herein is the formation of a trailing access tunnel
behind the
excavation/mining machine. After a volume of the hydrocarbon ore body is mined
out, there will remain a network of such access tunnels. Figure 42 shows a
side
schematic view of a special rock bolt that penetrates the access tunnel wall
and can
be used to tap gas from the surrounding formation and an isometric schematic
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illustrating how the rock bolts can be positioned around the access tunnel. A
special
rock or sand bolt concept for gas drainage is illustrated in Figure 42a. In
one
configuration, a bolt 4200 is installed through the tunnel liner 4201 into the
formation
4202. The bolt 4200 has a passage 4203 which connects an exit port 4204 in the
bolt
head 4205 to a series of perforations 4206 along the length of the bolt 4200.
When
the gas from the formation 4202 is at a higher pressure than the ambient
pressure in
the tunnel, the gas will flow through the formation 4202, enter the
perforations 4206,
flows down the passage 4203 and enters a gas collection system 4207 which is
connected to the exit port 4204. A valve 4208 is set so that the gas can only
flow into
the collection system 4207. The same bolt is shown in Figure 42b for injecting
gases
into the formations. A bolt 4250 is installed through the tunnel liner 4251
into the
formation 4252. The bolt 4250 has a passage 4253 which connects an exit port
4254
in the bolt head 4255 to a series of perforations 4256 along the length of the
bolt
4250. When the gas in the tunne14257 is at a higher pressure than the pressure
in the
formation 4252, the gas will flow down the passage 4253, exit the bolt 4250
through
the perforations 4256, be injected into the formation 4252. A valve 4258 is
set so that
the gas can only flow from the tunnel 4257 to the formation 4252. The bolt
described
above is preferably in the range of 20-mm to 60-mm diameter. The length of the
bolt
is preferably in the range of 0.1 to 0.75 times the access tunnel diameter or
principal
dimension. Figure 42c illustrates an example of how gas drainage/injection
bolts
could be installed in a section of tunnel 4270. Gas bolts 4270b may be
arranged so
that a gas bolt penetrates into both sides of the formation 4271 and into the
top of the
formation 4272. Gas bolts may be installed in such a pattern at intervals 4273
along
the length of the tunne14270. Although not shown, gas bolts may also be
installed in
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the floor of the tunnel 4274 to drain or inject gases in the formation below
the tunnel.
The gas bolt heads can be recessed in the tunnel floor.
TBM Cutters
As will be appreciated, any suitable cutter configuration can be used on the
tunnel boring machine. For example, Figure 43 shows examples of possible
cutter
tools that can be used in a tunnel boring machine configuration preferred for
mining
in the present invention. Drag bits 4301, picks 4302 and disc cutters 4303 are
shown.
These tools can be augmented by water jets that can be aimed at or near where
the
tools contact the rock or compacted soil so as to increase the efficiency of
breakage
and reduce the wear on the cutting edges.
The foregoing discussion of the invention has been presented for purposes of
illustration and description, the foregoing is not intended to limit the
invention to the
form or forms disclosed herein. Although the description of the invention has
included description of one or more embodiments and certain variations and
modifications, other variations and modifications are within the scope of the
invention, e.g., as may be within the skill and knowledge of those in the art,
after
understanding the present disclosure. It is intended to obtain rights which
include
alternative embodiments to the extent permitted, including alternate,
interchangeable
and/or equivalent structures, functions, ranges or steps to those claimed,
whether or
not such alternate, interchangeable and/or equivalent structures, functions,
ranges or
steps are disclosed herein, and without intending to publicly dedicate any
patentable
subject matter.
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