Note: Descriptions are shown in the official language in which they were submitted.
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METHOD AND SYSTEM FOR GENERATING A DRILLING PATTERN, AND A
ROCK DRILLING RIG
Field of the invention
The present invention relates to rock excavation, and in particular to a
method and
system for generating a drilling pattern during rock excavation. The invention
also
relates to a rock drilling rig, as well as a computer program and a computer-
readable
medium that implement the method according to the invention.
Background of the invention
Rock excavation, in particular underground rock excavation, may be carried out
using
various techniques, where excavation using drilling and blasting technology is
a
commonly used method. The excavation may consist in the creation of a rock
cavity
having a predefined shape and geographical location. This may be the case, for
example, when creating tunnels or other kinds of underground cavities.
Excavation
using drilling and blasting is, in general, carried out in a manner in which
drilling is
performed in rounds, where a round of holes is drilled to thereafter be loaded
with
explosives to blast the rock. Following removal of rock being detached by the
blasting, a new round of holes are drilled to blast a subsequent portion of
the cavity
to be created. This is repeated until excavation of the desired cavity has
been
completed.
In order to achieve a rock excavation that results in a desired cavity being
created,
each round of holes are being drilled according to a drill plan, or drilling
pattern,
which essentially determines location, direction, length and possibly diameter
of the
holes to be drilled. The object of the drilling pattern is to create a cavity
using drilling
and blasting that has a cross-sectional shape and geographical alignment that
in
reality corresponds to the planned, i.e. desired, shape and alignment.
Cavities of this kind may be of various designs. For example, the cavity may
be
designed to have essentially the same cross-sectional appearance following an
essentially straight line. However, as is oftentimes the case, properties of
the cavity,
e.g. in terms of cavity cross section and curvature, may vary along the length
of the
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cavity. This may require utilization of different drilling patterns for
different sections of
the cavity to be excavated.
With regard to, for example, tunnels, but also other kinds of cavities, these
are
oftentimes associated with highly precise requirements regarding conformance
with
the desired cavity cross section and geographic alignment/extension. For
example,
lining such as concrete lining may be utilised, where over-break of rock
result in an
increased consumption of lining and oftentimes also an increase in the
requirement
of rock reinforcement. Insufficient breaking, under-breaking, on the other
hand, may
require additional drilling and blasting to obtain the desired cavity. Hence,
well-
designed drilling patterns and subsequent drilling in accordance with the
drilling
patterns is essential in order to achieve the desired result.
Summary of the invention
It would be advantageous to achieve a method and system that may be utilised
to
obtain a drilling pattern for rock excavation that may reduce surplus rock
when
excavating a cavity in conformance with predetermined geographical
alignment/extension.
According to the present invention, it is provided a method for generating a
drilling
pattern for excavating a cavity in rock, the drilling pattern determining
holes to be
drilled in a face of the rock, the determination of the holes to be drilled
being a
determination of location, direction and length of the holes to be drilled,
the holes
being arranged to be drilled by a drilling rig, the holes of the drilling
pattern being
drilled prior to subsequent blasting of the face of the rock, the method being
characterised in:
- determining a face contour being a representation of the rock face to be
drilled and constituting a cross section of the cavity in a plane representing
the rock
face to be drilled,
- determining a first bottom contour being a representation of a cross
section
of the cavity to be drilled at a first distance from the face contour,
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- determining at least one second bottom contour being a representation of
a
cross section of the cavity to be drilled at a second, different from said
first, distance
from the face contour, and
- when determining said holes to be drilled, determining holes to be
drilled
between the face contour and the first bottom contour, and holes to be drilled
between the face contour and the second bottom contour.
The drilling pattern may be generated prior to excavation of the cavity
commences.
The drilling pattern may comprise holes to be drilled subsequently to the
generation
of the drilling pattern.
The plane representing the rock face to be drilled may be determined as any
plane
generating a cross-section of the cavity, e.g. representing a cross-section at
most
three or four metres from the closest part of the rock face to be drilled,
where the rock
face may be bowl-shaped, in a direction opposite the direction of excavation,
such
that the plane substantially or completely clears the unbroken rock.
As was mentioned above, the drilling pattern being used in rock excavation
using
drilling and blasting technology is an important factor in order to achieve a
cavity
having a cross section and geographical extension that conforms to a high
extent to
the planned alignment of the cavity. Drilling patterns, also known as drill
plans, define
the location, position, of the holes to be drilled in a rock face of the rock
to be
excavated, and also the direction and length of the holes. The drilling
pattern may
also determine the diameter of the hole to be drilled, where e.g. holes along
a
periphery of the contour, i.e. cavity profile, outline or cross-section, to be
drilled may
be of a different diameter than holes more to the centre of the rock portion
to be
excavated. Contour is used in the following as a representation of cavity
profile/outline/cross-section.
The drilling pattern is generated on the basis of the contour/profile of the
cavity to be
created, and a plurality of consecutive rounds of drilling and blasting are in
general
required to create the desired cavity, such as a tunnel.
Drilling patterns may be generated in various manners as is known to the
person
skilled in the art, and are oftentimes generated beforehand, i.e. prior to
excavation of
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the cavity commences, e.g. in a control/planning centre, to then be downloaded
to
the rock drilling rig for use in the excavation.
Rock excavation often results in surplus rock being broken, and this is also
often
necessitated by constructional constraints that hinders optimal positioning of
a drilling
rig/drilling machine used in the excavation, which thereby renders it
difficult to drill
holes that result in excavation without surplus rock being broken. Surplus
cavity
formed during tunnel excavation is oftentimes subject e.g. to subsequent
concrete
lining, where the surplus rock being broken also results in additional
consumption of
concrete e.g. in concrete lining operations and may also generate an increase
in
required rock reinforcement following blasting. Drilling patterns are in
general
designed to reduce the amount of surplus rock being broken, but it may not
always
be possible to drill completely according to the predetermined drilling
pattern.
According to the invention, when generating the drilling pattern, a face
contour is
determined, which represents the rock face to be drilled, the face contour
constituting
a cross-section of the cavity in a plane, denoted navigation plane, which as
mentioned may be determined as any plane in which a cross-section of the
cavity in
a longitudinal direction, i.e. direction of excavation, and which is suitable
to use to
represent the rock face to be drilled, can be represented. The navigation
plane may
e.g. be a plane in which a cross-section at most e.g. three or four metres
from the
closest part of the rock face to be drilled, e.g. in a direction opposite the
direction of
excavation so that the plane substantially or completely clears the unbroken
rock.
The navigation plane may further be defined at any angle in relation to the
actual
rock face to be drilled, and hence need not be parallel to this rock face.
Further, a first bottom contour being a representation of a cross section of
the cavity
to be drilled at a first distance from the face contour, substantially in a
direction into
the rock to be drilled, where the distance at least substantially correspond
to a length,
such as a maximum length, of the holes to be drilled as measured from the face
contour. Since the face contour may be at a distance from the rock, the actual
hole
length in rock may be shorter.
It is further determined at least one second bottom contour, being a
representation of
a cross section of the cavity to be drilled at a second, different from said
first,
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distance from the face contour. When the drilling pattern is generated it is
determined
holes to be drilled between the face contour and the first bottom contour, and
holes
to be drilled between the face contour and the second bottom contour. In this
way,
holes can be drilled towards different contours, i.e. profiles/cross sections
of the
5 cavity to be drilled, so that the blasting following a round of drilling
may result in a
cavity having a high correspondence to the desired cavity outline.
The first distance may be longer than said second distance, so that holes to
be drilled
between the face contour and the first bottom contour may be longer than holes
to be
drilled between the face contour and the at least one second bottom contour.
In this
way, changes e.g. in the cross section and/or curvature of the cavity to be
drilled may
be accounted for by the additional bottom contour. Holes to be drilled between
the
face contour and the second bottom contour does not extend to said first
bottom
contour.
The holes to be drilled between the face contour and the first bottom contour
may be
arranged to end substantially at the first bottom contour, and holes to be
drilled
between the face contour and the second bottom contour may be end
substantially at
said second bottom contour.
The second bottom contour may hence be an intermediate bottom contour, and, a
plurality of such intermediate bottom contours between the face contour and
first
bottom contour may be defined, where each of said intermediate contours may
represent a cross section of the cavity at different distances from the face
contour
towards the first bottom contour.
The holes to be drilled between the face contour and an intermediate contours
may
be arranged to end substantially at the intermediate contour towards which the
hole
is to be drilled.
The number of intermediate contours may be determined in different manners,
e.g.
based on a curvature and/or change in width or height of the cavity to be
excavated.
The number may also be e.g. determined beforehand, such as by an operator or
other personnel.
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The first bottom contour may be used to generate the drilling pattern for a
first part of
the face contour, i.e. holes of the first part of the face contour extending
substantially
to the first bottom contour, and the at least one second bottom contour,
and/or each
of the intermediate bottom contours may be used when generating a drilling
pattern
of a second part of the face contour being different from said first part,
where each
intermediate bottom contour may be used for different parts of the face
contour.
Further, according to embodiments of the invention, e.g. exemplified below,
the
number of intermediate contours may be determined based on the size of the
part/portion of the face contour that is not to be drilled towards the first
bottom
contour.
According to embodiments of the invention, the first part of the face contour,
i.e. the
part for which holes is to be drilled towards the first bottom contour, may be
determined using the first bottom contour. For example, the first bottom
contour may
be projected onto the plane of the face contour, and the part of the face
contour
encompassed by the projection may be used as said first part of the face
contour.
Similarly, the one or more second parts may be determined using said one or
more
second/intermediate bottom contours in a similar manner, where overlaps in the
generation of the different parts of the face contour may be disregarded so
that the
parts are non-overlapping.
The parts of the face contour may also e.g. be determined using a limiting
contour
according to the below.
According to embodiments of the invention, a limiting contour may be
determined,
which is a representation of the cross section of the cavity at a distance
from the face
contour in a direction away from the rock to be excavated. The limiting
contour may
be used, for example to take into account limitations regarding
manoeuvrability of the
drilling rig when drilling the holes of the drilling pattern, so that such
limitations may
be accounted for already when generating the drilling pattern. The limiting
contour
may, for example be a representation of the cross section of the cavity at a
distance
from the face contour in a direction towards already drilled rock
substantially
corresponding to the length of a feed beam of the drilling rig. It is in
general the rear
end of the feed beam that will impose limitations to manoeuvrability during
drilling,
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and ensured manoeuvrability can be obtained by determining the manoeuvrability
of
the rear end in relation to the cavity contour prevailing at its location.
According to
embodiments of the invention, the limiting contour is determined utilising a
representation of actual rock walls, resulting from blasting of one or more
previous
rounds of drilling, where the representation of the actual rock walls can be
generated
e.g. by one or more scanners, e.g. located on the drilling rig. In this way,
the limiting
contour may be larger, and e.g. manoeuvrability of the feed beam may be
determined
in relation to actually excavated rock, which, e.g. in case of over-breaking,
may allow
further manoeuvrability.
According to embodiments of the invention, the limiting contour is at any
distance
from the face contour in the direction away, e.g. opposite, from the general
direction
that the cavity is to extend into the rock.
According to embodiments of the invention, the first part of the face contour
is
determined utilising interpolation between the limiting contour, which hence
is located
in one direction from the face contour and the first bottom contour, which is
located in
another direction from the face contour, where the interpolation is made in
the plane
of the face contour.
This first part of the face contour may represent a part for which holes
having a
length determined by the distance between the face contour and the first
bottom
contour, i.e., for example, the maximum length of holes to be drilled in the
round, can
be drilled without giving rise to problems regarding manoeuvrability of e.g. a
feed
beam. Since the face contour defines the maximum surface to be drilled, the
interpolation may be delimited also by the face contour so that the first part
forms part
of the face contour and does not extend outside the face contour even if this
would
be the result from the interpolation. In this way, in particular because of
the use of the
limiting contour, a part/portion of the face contour can be determined, where
it can be
ensured that the holes of the drilling pattern can be drilled, and to a
desired, e.g. full,
length, fulfilling set conditions, avoiding e.g. feed beam manoeuvring
imposing
limitations once drilling is started. The drilling rig may comprise at least
one feed
beam carrying a drilling machine, where the drilling machine may be slidable
along
the feed beam.
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According to embodiments of the invention, the first part of the face contour
is
determined using projection of the limiting contour and/or said first bottom
contour
onto the face contour instead of utilising interpolation. The method utilising
projection
may be used also when interpolation is used, where in addition to the
interpolation,
projection may be utilised, by projecting one or both the limiting contour and
the first
bottom contour onto the face contour, to further reduce the area of said first
part. In
this way, instead, the remaining part is increased, and for which holes of a
reduced
length may be drilled. For example, this may be utilised when otherwise the
remaining part of the face contour becomes undesirably small so it may e.g. be
difficult to get room for a further, or a desired number of, holes or rows of
holes to be
drilled in the remaining part.
The one or more further parts of the face contour may be determined in a
similar
manner, e.g. utilising interpolation and/or projection, for each part
utilising an
intermediate bottom contour instead of the first bottom contour. With regard
to the
portion of the face contour for which holes having a shorter length than holes
of said
first part, i.e. the remaining part of the face contour, it can be determined,
e.g. on the
basis of the width of the remaining portion of the face contour and/or the
number of
holes to be drilled on this remaining portion, the number of intermediate
bottom
contours to be used.
A drilling pattern is hence generated for different parts/portions of said
face contour
for each of said intermediate contours utilising said intermediate contour,
respectively, using interpolation and/or projection. The holes of these at
least one
additional drilling pattern will hence have a shorter longest length than the
holes of
the first part of the face contour above.
A drilling pattern encompassing the full, or substantially the full, face
contour can
consequently be determined, where the drilling pattern may be seen as an
aggregate
of drilling patterns for different parts of the face contour, where different
longest hole
lengths are used for the different parts of the face contour, and where the
longest
hole length of a drilling pattern may be determined by a distance between the
face
contour and intermediate or first bottom contour. Further, when holes of
drilling
patterns for different parts of said face contour are located within less than
a first
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distance from each other, thereby considered to have overlapping coverage of
the
rock to be drilled, holes of at least one of the drilling patterns can be
omitted. For
example, the hole having the shortest, or longest for that matter, length, can
be
arranged to be omitted.
The use of contours according to the above may allow generation of an
aggregate
drilling pattern that comprises holes having a drillability, i.e. the holes
will be able to
be drilled by the rock drilling rig. This drillability of the holes may be
determined e.g.
by ensuring a manoeuvrability of the feed beam in relation to surrounding
rock, which
may be accomplished through the use of said limiting contour. In this way, a
drilling
pattern can be generated that may ensure that holes of the drilling pattern
are also
drillable in reality, so that adaptions of the drilling pattern during ongoing
drilling of a
round due to holes not being possible to drill can be reduced, which thereby
may
reduce the risk of over-breaking and/or under-breaking of rock resulting from
adaptions of the drilling pattern during ongoing drilling.
According to embodiments of the invention, the drilling pattern is generated
following
drilling and blasting of a previous round.
The rock drilling rig may comprise a plurality of feed beams, each carrying a
drilling
machine, and the determination may be performed for the particular feed beam
that
is to drill an intended hole.
According to embodiments of the invention, the drilling pattern is determined
when
the cross section, contour, of the cavity is narrowing or widening in the
direction of
excavation, and/or a curvature of the cavity is changing. It is oftentimes in
situations
of these kinds that limitations regarding e.g. the manoeuvrability of the feed
beam
may have the most negative impact when drilling a drilling pattern where this
manoeuvrability has not been accounted for. The drilling pattern may also be
determined when a straight portion is to be drilled immediately following a
narrower
portion of the cavity, in which case the narrower portion may impose
limitations
regarding e.g. manoeuvrability regarding e.g. a feed beam of the drilling rig.
According to embodiments of the invention, the drilling pattern is determined
when
the cross section, contour, of the cavity is changing such that different
drilling
patterns are used for consecutive rounds of drilling and blasting.
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According to embodiments of the invention, the drilling pattern is determined
when
excavation of the cavity has progressed to an extent at least corresponding to
the
length of the feed beam.
It will be appreciated that the embodiments described in relation to the
method
5 aspect of the present invention are all applicable also for the system
aspect of the
present invention. That is, the system may be configured to perform the method
as
defined in any of the above described embodiments. Further, the method may be
a
computer implemented method which e.g. may be implemented in one or more
control units of a rock drilling rig.
10 Further characteristics of the present invention and advantages thereof
are indicated
in the detailed description of exemplary embodiments set out below and the
attached
drawings.
Brief description of the drawings
Fig. 1A-B illustrates an exemplary representation of a part of a tunnel to be
excavated;
Fig. 2 illustrates an exemplary embodiment of a rock drilling apparatus in
which
embodiments of the invention may be utilised;
Fig. 3 illustrates an exemplary method for generating a drilling pattern
according to
embodiments of the invention;
Fig. 4 illustrates an exemplary method for reducing the risk that under-
breaking of
rock occurs;
Fig. 5 illustrates a further method for generating a drilling pattern
according to
embodiments of the invention;
Fig. 6A illustrates an exemplary representation of a part of a tunnel to be
excavated,
including a bottom contours utilised when generating a drilling pattern
according to
embodiments of the invention;
Fig. 6B illustrates an exemplary representation of a plurality of bottom
contours in the
tunnel example of fig. 6A;
Fig. 6C illustrates a limiting contour in the tunnel example of fig. 6A.
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Fig. 7 illustrates determination of a contour for drilling of full-length
holes, forming part
of a rock face to be drilled;
Fig. 8 illustrates the cross sectional appearance of the contour for drilling
of full-
length holes in relation to the rock face to be drilled;
Fig. 9 illustrates the cross sectional appearance of the contour for drilling
of holes
having a reduced length in relation to the rock face to be drilled;
Fig. 10 illustrates a method for determination of contours for drilling holes
having a
reduced length, the contours forming part of a rock face to be drilled;
Fig. 11 illustrates holes to be drilled from a face contour towards bottom
contours
according to embodiments of the invention;
Fig. 12 illustrates a method for increasing the cross-sectional appearance of
the
contour for drilling of holes having a reduced length in relation to the rock
face to be
drilled;
Fig. 13 illustrates an example of an excavation situation where the invention
may be
utilised;
Fig. 14 illustrates a further example of an excavation situation where the
invention
may be utilised.
Detailed description of exemplary embodiments
Embodiments of the invention will be exemplified in the following with
reference to
examples relating to excavation of a tunnel. Figs. 1A-B illustrates an
exemplary
representation of a section of a tunnel to be excavated in rock. The tunnel
may be
any kind of tunnel for any suitable use, and e.g. comprise a tunnel forming
part of a
mine, or a tunnel for road or railway transport.
According to the example, the tunnel is represented by a tunnel line TL, which
essentially is defined by points TLn-3, TLn-2... TLn+2 which may be
interconnected.
The extension, alignment, of the tunnel in the longitudinal direction may
hence be
obtained by interconnecting the tunnel line points. The disclosed section of
the tunnel
to be excavated represents a section of the tunnel about n tunnel line points
into the
tunnel. The tunnel line points are defined in a 3D-coordinate system being
used in
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the excavation, e.g. a global coordinate system or a coordinate system local
to the
area of excavation, so that the desired tunnel can be excavated in conformity
with the
pre-planned tunnel alignment.
Any suitable number of tunnel line points may be used in the representation of
the
tunnel, where the number e.g. may depend on the length of the tunnel to be
excavated, and any suitable, constant or varying, distance between the tunnel
line
points may be used, e.g. in dependence of curvature. For example, the distance
between tunnel line points may represent the length of the longest holes to be
drilled
during a round for subsequent blasting. The length of the holes to be drilled
may e.g.
correspond to the length along a feed beam that a drilling machine may slide,
and
e.g. be in the order of 0-10 metres.
In order to obtain a 3D-representation of the tunnel alignment, e.g. a
representation
of the desired tunnel cross section, in the following denoted tunnel contour,
or tunnel
profile, may be defined for each tunnel line point, e.g. in a plane
perpendicular to the
tunnel line TL. The tunnel contours of different tunnel line points may be
defined in a
same plane, but may also be defined in different non-parallel planes. An
example of
a tunnel contour 101 is disclosed in fig. 1B, exemplifying a tunnel contour
101 of
tunnel line point TLn, and which also indicates the location of the associated
tunnel
line point TLn in relation to the tunnel contour 101. For simplicity, the
tunnel line point
TLn is shown as being located essentially in the centre of the tunnel contour
101 of
fig 1B, but it may be arbitrarily located on, or principally anywhere on a
plane of, the
tunnel contour 101 for as long as the relation between tunnel line point and
tunnel
contour is defined. Positioning of the desired tunnel contour to encompass the
associated tunnel line point may be advantageous e.g. from a navigation point
of
view during actual excavation.
The interconnected tunnel line points together with the associated tunnel
contours,
which may vary in shape from one tunnel line point to another can be used to
form a
3D-volume through interpolation representing the tunnel and which is being
defined
in a coordinate system to allow excavation at a desired location.
Consequently, the
tunnel is represented by tunnel contours distributed along the tunnel line TL
representing the desired extension of the cavity to be excavated. In case the
tunnel
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contours differ from one tunnel line point to another, e.g. interpolation can
be utilised
in a straight-forward manner to obtain a tunnel cross-section also at any
point
between the defined tunnel line points. In case the tunnel contours are
defined in a
same plane 2D-interpolation may be utilised, while otherwise 3D-interpolation
may be
utilised to determine an intermediate tunnel contour in any desired plane.
Tunnel/cavity excavation of this kind often involves generation of a drill
plan, in the
following denoted drilling pattern, for drilling of a set, or round, of drill
holes in a rock
face for subsequent blasting. The drilling pattern defines the holes to be
drilled, e.g.
in the coordinate system of the tunnel, and may define position, length and
direction
for each hole. Holes having different diameters may also be drilled, and hence
a hole
diameter may be defined by the drilling pattern as well. Following drilling of
a round,
the drilled holes are charged with explosive material that is detonated
following
drilling and charging of the holes of the drilling pattern.
After the explosion, broken rock is taken away and following scaling, if
required, i.e.
clearing and loosening of cracked and/or partly loose rock resulting from the
blasting,
a new round is drilled and blasted to progress the excavation of the tunnel.
This is
then repeated until the complete volume of the desired tunnel/cavity has been
excavated. When generating a drilling pattern of a round to be drilled the
object is in
general to design the drilling pattern such that the cavity formed by the
blasting
following the drilling results in a cavity having a spatial extension that at
least clears
the rock encompassed by the 3D-representation of the desired cavity, such as
the
cavity defined by an interpolation of the tunnel line points and associated
contours. In
reality surplus rock is oftentimes excavated in addition to the breaking of
rock forming
the desired cavity. This is due to a difficulty in breaking rock precisely
according to
desired cavity boundaries. It is, however, usually a requirement that the
desired
cavity is also excavated in full, i.e. the complete cross section of any given
point of
the tunnel being cleared from rock, and in order to ensure that at least this
is
accomplished surplus rock is oftentimes broken to ensure that under-breaking
does
not take place. The drilling pattern may be designed in an attempt to reduce
the
breakage of surplus rock as much as possible while still ensuring that at
least the
desired cavity is excavated.
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Fig. 2 illustrates an exemplary movable rock drilling rig 201 that may be
utilised e.g.
in tunnel excavation. The rock drilling rig 201 is an underground drilling rig
and is
shown in position for drilling a round of holes in a rock face 202 during
tunnel
excavation, e.g. along the tunnel line TL of fig. 1A.
As can be seen in fig. 2, the rock drilling rig 201 according to the disclosed
example
is provided with three booms 203-205, each of which is carrying a drilling
machine
206-208 via feed beams 209-211. Accordingly, the disclosed rock drilling rig
201 may
drill up to three holes at a time. Drilling rigs of the disclosed kind are
known per se.
The drilling machines 206-208 are, in this example, hydraulically driven and
power
supplied from one or more hydraulic pumps 212, which in turn are driven by one
or
more electric motors and/or combustion engines 213, also in a manner known per
se.
The drilling process may be controlled by an operator from a cabin 215.
The drilling rig 201 further comprises a control system comprising at least
one control
unit 214, which controls various of the functions of the drilling rig 201,
e.g. by suitable
control of various actuators/motors/pumps etc. Drilling rigs of the disclosed
kind may
comprise more than one control unit, where each control unit, respectively,
can be
arranged to be responsible for different functions of the drilling rig.
The drilling rig 201 is arranged to be repositioned as excavation progresses
and
comprises, according to the present example, wheels 216, 217 for allowing
drilling rig
movability. Crawler drives or other suitable means may alternatively be used
to allow
manoeuvring of the drilling rig 201.
Fig. 2 hence discloses a drilling rig that following a previous blast and
clearing of
broken rock has been moved forward in the excavating direction, i.e. along the
tunnel
line TL, towards the rock face 202 resulting from the previous blast and the
drilling rig
201 has been positioned for drilling the subsequent round for blasting of the
next
section of the tunnel/cavity to be excavated. In order to correctly excavate
rock
according to the predetermined tunnel alignment, the exact position of the
rock
drilling rig 201 in the prevailing coordinate system must be determined. This
can be
accomplished in various ways and, for example, by aligning one of the feed
beams,
e.g. feed beam 211 to a laser beam of a theodolite (not shown), where the
position of
the theodolite in turn has been established using fixed points.
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The drilling rig in 201 general comprises a local rig coordinate system, and
through
the use of the drilling rig coordinate system the position of the drilling rig
can be
determined using the location of the feed beam in the drilling rig coordinate
system
and the location of the feed beam as determined in the coordinate system of
the
5 tunnel. In addition to the feed beam being aligned with a laser beam of a
theodolite,
the position of the feed beam along the laser beam must also be determined.
This
can be performed e.g. by straight-forward measurement or in any other way.
For example, the length of the tunnel that so far has been excavated from the
beginning of the excavation, i.e. the drilled and blasted length of the
tunnel, may e.g.
10 be marked on the tunnel wall to facilitate positioning of the drilling
rig. As is realized,
any other suitable method of positioning the drilling rig in the coordinate
system of the
tunnel to be drilled may be utilized. According to embodiments of the
invention, the
drilling rig is provided with fixed points, which may be used to position the
drilling rig
using e.g. a theodolite, and where the rig fixed points are also defined in
the
15 coordinate system of the drilling rig, so that thereby e.g. the position
of a feed beam
may be determined in the coordinate system of the tunnel.
As before mentioned, prior to drilling of the rock face 202 commences, a
drilling
pattern is generated, and fig. 3 illustrates a flowchart for generating a
drilling pattern
to be drilled prior to blasting the current rock face 202. The positions of
the holes to
be drilled on the rock face are schematically illustrated by "x" markings,
where these
positions are determined by the drilling pattern. The drilling pattern to be
used is
oftentimes determined prior to the excavation of a tunnel commences e.g. in a
planning centre, where the holes are planned such that the subsequent blasting
as
close as possible corresponds to the desired cavity to be excavated. The
generation
of the drilling pattern that is optimal from an excavation point of view, e.g.
with regard
to surplus rock being broken, may be difficult, in particular when excavation
is in
progress and the excavation has progressed to a position along the tunnel line
that
does not correspond to a position for which drilling is planned to be
performed on the
planning stage. According to the invention, it is provided a method for
generating a
drilling pattern that may be used when a rock face is to be drilled and which
may
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reduce the amount of surplus rock being broken during the excavation. This is
accomplished, inter alia, through the use of a plurality of bottom contours.
The method 300 according to embodiments of the invention of fig. 3 starts in
step
301 by determining whether a drilling pattern is to be generated. This may be
initiated
e.g. by an operator of the drilling rig 201, e.g. by suitable input to the
drilling rig
control system, or by any other suitable means. The method continues to step
302
when a drilling pattern is to be generated while otherwise the method remains
in step
301.
In general when generating a drilling pattern, holes to be drilled close to
the periphery
of the rock face are subject to limitations regarding possible hole direction.
This is
due to the inherent diameter/size of the drilling machine/feed beam. That is,
it is not
possible to drill precisely along a contour outline but drilling will have to
be performed
slightly outwards in relation to the desired direction to make room for
drilling
machine/feed beam when drilling the next round of holes following blasting of
the
current round. This is known per se, and the general principle is illustrated
in fig. 4, in
which a desired width of a tunnel to be drilled is indicated with a. The
actual drilling is
represented as a saw tooth pattern 401, in which the distance b is essentially
governed by the dimensions of the drilling machine/feed beam, and where the
distance b ensures that the width of the tunnel can be maintained at the
subsequent
round.
That is, if the distance b is made smaller in one round, this may make
drilling difficult
in a following round, so that the drilling e.g. will be directed more outwards
due to
space limitations. Fig. 4 merely illustrates a general principle, and the
outward
angulation c may be determined in any suitable manner, in general in an
attempt to
limit over-breakage of rock, where the outward angulation c may vary from one
round
to another.
According to the invention, a drilling pattern is generated in a manner that
utilizes a
plurality of bottom contours, i.e. cavity cross-sections towards which holes
are being
drilled from the face contour FC in order to obtain an excavation this
corresponds to
the desired outline of the cavity to be excavated.
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In step 302 a face contour FC of the current rock face to be drilled is
determined. The
face contour FC is determined for a plane, here denoted navigation plane NP as
is
commonly the case, from which hole length, direction etc. of the holes to be
drilled is
determined. The navigation plane and face contour are exemplified in fig. 6A,
which
illustrates a tunnel line TL similar to the tunnel line of fig. 1A, but where
in addition the
desired outline 601 of the tunnel as seen from above is also illustrated. In
addition,
the actual rock walls 602 of the already excavated portion of the tunnel are
shown,
including the rock face 603 about to be drilled as the excavation progress. As
has
been discussed above, the tunnel line points are defined in the coordinate
system
being used in the excavation, and in the present example drilling has reached
a point
between TLn and TLn+1.
Even if, prior to the excavation of the tunnel commences, it may be an
intention to
drill consecutive rounds at consecutive tunnel line points, drilling may not
progress
precisely according to pre-planned drilling patterns, where each round of
drilling and
blasting may be expected to reach the next tunnel line point of the tunnel
line TL. For
example, the blasting may not break the full length of a hole, and/or a larger
portion
of rock may be broken, e.g. due to more porous rock. According to embodiments
of
the invention, however, the drilling pattern for the next round is established
only once
the location of the rock face to be drilled has been determined, and is
independent
from the current progress in relation to the tunnel line points.
As can be seen from fig. 6A, the resulting rock face 603 from the preceding
blast is
uneven, and may vary considerably. The navigation plane NP may be determined
such that it substantially or completely clears the rock face 603 to be
drilled, but the
navigation plane NP may also be arranged to partially or fully intersect the
rock face
603 to be drilled. The rock face may be established e.g. by positioning the
drilling rig
according to the above using the coordinate system of the drilling rig in
combination
with the position of the drilling rig in the coordinate system of the tunnel,
where the
representation of the rock face can be expressed in the coordinates of the
coordinate
system being used for excavation of the tunnel.
When the position of the rock face in the coordinate system of the tunnel has
been
determined, a suitable navigation plane can be determined, where the
navigation
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plane NP may be defined in various ways, and according to the present example,
the
navigation plane NP is defined such that it is perpendicular to a line, dashed
line 605,
representing an intended drilling direction of the round to be drilled. The
intended
drilling direction may, as in the present example, differ from the direction
of the tunnel
line TL at the point where the tunnel line TL is intersected by the navigation
plane
NP. For example, the direction of drilling may be determined by a line 605
that
intersect the tunnel line TL at the point where the tunnel line TL is
intersected by the
navigation plane NP, and where the line 605 also intersects the tunnel line
TL, point
604, at some suitable distance from the navigation plane NP. The distance from
the
navigation plane NP to point 604 may correspond to, or substantially
correspond to,
the longest hole length to be drilled in the round for which the drilling
pattern is
generated. The distance from the navigation plane NP to the point 604 may also
be
any other suitable distance, greater or smaller than the longest hole length
to be
drilled in the round. For example, the distance may be set or changed from a
pre-set
value e.g. by an operator in case it is desired to change the drilling
direction, and in
which case the navigation plane may be automatically adjusted to be e.g.
perpendicular to the drilling direction. In the present example the navigation
plane NP
is hence determined such that line 605 is normal to the navigation plane NP.
The
navigation plane NP is hence defined independently from the general appearance
of
the rock face 603 to be drilled, and e.g. need not be parallel to this rock
face 603, but
may be angled considerably in relation to the actual rock face.
The navigation plane NP may also be defined independently from a drilling
direction,
and may essentially have any suitable angle in relation to e.g. the tunnel
line TL
and/or drilling direction 605 and/or rock face. There exist various methods in
the art
for determining a navigation plane NP, and any such method may be utilised.
For
example, the navigation plane NP can be arranged to be determined e.g. by an
operator of the drilling rig and/or other person involved in the generation of
drilling
patterns. Further, an intended drilling direction may be defined according to
any
suitable criteria and may have any suitable direction and hence need not be
defined
according to the example using tunnel line points described herein.
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The face contour FC is determined in the navigation plane NP, where the face
contour FC can be determined by 2D or 3D interpolation as explained above
using
the tunnel contours of TLn and TLn+1, depending on whether these tunnel
contours
are in a same plane or not, to obtain the face contour in the navigation plane
NP. The
tunnel line contours of adjacent tunnel line points may differ in shape from
one tunnel
line point to another, e.g. if the tunnel is widening, narrowing or otherwise
changing
shape, and may be defined in different planes, e.g. by the curvature changing
such
as in the present example, where tunnel line contours of tunnel line points
TLn and
TLn+1 are also in different planes with respect to the navigation plane NP.
The
navigation plane NP hence need not, and according to the present example is
not, be
perpendicular to the tunnel line at the point where this is crossed, and the
face
contour FC will therefore differ from the tunnel line contour even if the
tunnel contours
of adjacent tunnel line points TLn and TLn+1 are the same. The exemplified
method
is perhaps most advantageous when conditions for generating the drilling
pattern
differ from one round to another, in particular when the tunnel is widening,
narrowing
and/or the tunnel is curving or the curvature of the tunnel is changing.
The method then continues to step 303 in which, in a similar manner to the
above, a
bottom contour BCO is determined. The bottom contour BCO is determined in a
bottom plane BP, which is a plane at a distance from the face contour FC. The
bottom plane may be defined to be located at a distance from the face contour
FC,
e.g. defined by line 605 above, and hence at a distance e.g. corresponding or
substantially corresponding to the longest length of the holes to be drilled
in the
round for which the drilling plan is generated. The bottom plane BP may also
be
arranged to be located at any other, greater or smaller, distance from the
face
contour FC. The location of the bottom plane BP may also be arranged to be
adjusted by an operator of the drilling rig, e.g. by changing pre-determined
distance
between face contour FC and bottom plane BP in case this is desired, e.g. to
extend
or reduce the distance between the face contour/navigation plane and the
bottom
plane BP. The distance between the face contour and bottom plane may hence
exceed the longest hole length to be drilled. Further, in case the planes are
angled
with respect to each other, the distance between the planes will vary in
dependence
on where on the planes measurement is made, and hence the distance may be both
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greater and smaller than the longest hole length to be drilled even if e.g.
the distance
along the tunnel line equals the longest hole length to be drilled. The bottom
plane
BP, and thereby bottom contour BCO may be arranged to be perpendicular to the
tunnel line TL where this is intersected, i.e. at point 604 in the present
example.
5 According to embodiments of the invention, the bottom plane BP may
alternatively be
arranged to be perpendicular to the line 605, and hence be parallel to the
navigation
plane NP. The bottom plane may also be defined in any other suitable manner.
The
bottom contour BCO may be determined using 2D or 3D interpolation, in this
case
using tunnel line points TLn+1, TLn+2.
10 In addition to the bottom contour BCO, it is determined, step 304, at
least one
intermediate bottom contour. According to the disclosed example, two
additional
intermediate bottom contours BC1, BC2 are determined, see fig. 6B, where the
number of intermediate bottom contours can be determined in various manners.
For
example, the number of intermediate bottom contours may be determined on the
15 basis of the longest hole length to be drilled, such as, for example,
the distance
between the face contour FC and the bottom contour BCO. The number of
intermediate bottom contours may also be determined on the basis of e.g. the
curvature of the cavity that is about to be drilled. As will be discussed
below the
number of intermediate bottom contours may also be determined using other
criteria.
20 The intermediate bottom contours BC1...BCn can be generated in the same
manner
as BCO above, i.e. through interpolation using the tunnel contours of the
adjacent
tunnel line points. With regard to the location of the bottom contours
BC1...BCn,
these can be arranged to be evenly spaced between the face contour FC and the
bottom contour BCO. For example, if only one additional drilling pattern is to
be
generated, the additional bottom contour BC1 can be arranged to be positioned
at
half the distance from the face contour FC to the bottom contour BCO.
According to the present example, two additional bottom contours BC1, BC2 are
generated, which are evenly spaced between the face contour FC and the bottom
contour BCO. This is illustrated in fig. 6B, where the two intermediate planes
BC1,
BC2 are shown.
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According to the present example, holes of different portions of the face
contour FC
are determined to be drilled towards the different bottom contours. The bottom
contours BCO, BC1, BC2 are then used to determine portions of the face contour
FC
for which drilling is to be performed towards the various bottom contours,
step 305.
Fig. 6B schematically illustrates a larger portion of the face contour denoted
MCO
(dashed line) representing a portion of the face contour where holes will be
drilled
towards the bottom contour BCO and thereby have a longer hole length than
holes
being drilled towards intermediate bottom contours BC1, BC2. The division of
the
face contour FC into the various contours MCO, MC1 (solid line), MC2 (dash-
dotted
line), where MC is used to denote the maximum contour herein the reason for
this
being MC denoting the maximum portion of the face contour that according to
the
drilling pattern generation method is utilized to denote the largest portion
of the face
contour for which the hole length at hand may be drilled. For example, MCO is
the
maximum part/portion of the face contour for which holes extending to bottom
contour BCO is drilled. MC1 is the maximum part/portion of the face contour
for which
holes extending to bottom contour BC1 is drilled, but where the part covered
by MCO
is disregarded from, hence, according to the present example, leaving a
smaller part.
Similarly MC2 is a part for which holes extending to bottom contour BC2 is
drilled, but
where the parts covered by MCO and MC1 are disregarded from. This will be
exemplified further below with reference to the method disclosed in fig. 5.
According to the present example, the contours MCO etc. are defined by a
maximum
drilling angle in relation to the general drilling direction that it is
desired to use when
drilling the holes, i.e. line 605 according to the present example. The
drilling angle
may be defined e.g. in a xyz coordinate system, and the maximum allowed
difference
in drilling angle may be measured in a horizontal plane as in the present
example,
but may alternatively or in addition be measured in relation to line 605 in
any plane.
According to the present example, these drilling directions are denoted 621,
622,
623, in FIG 6B, where hence a maximum allowed drilling angle difference e.g.
in the
horizontal plane between line 605 and lines 621,622, 623 may be defined. The
drilling direction represented by dotted line 621 meets the bottom contour BCO
at the
outline of the contour (i.e. rock wall), and since line 621 is angled in
relation to line
605 according to the set criteria the intersection of line 621 with the face
contour FC
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defines the portion MCO of the face contour FC. The angle criteria may be
utilised
along the outline of the bottom contour BCO in relation to drilling direction
605 to
thereby form an area MCO in the plane of the face contour FC.
The maximum angle to be used in the drilling may be set in the control system
of the
drilling rig, and using these data contour MCO may hence be determined.
Similarly
contours MC1, MC2 may be determined for each of the intermediate bottom
contours
BC1, BC2. When the contours have been determined, a drilling pattern is
generated
in step 306.
According to the present example, the maximum contour MCO will represent the
largest portion of the face contour, and when the drilling pattern is
generated holes
being generated for this maximum contour MCO will hence constitute a drilling
pattern
of holes to be drilled from face contour FC to the bottom contour BCO. The
actual
drilling pattern, i.e. the precise condition of the location direction the
length of the
holes to be drilled can be generated according to any suitable method for
generating
a drilling pattern for drilling a contour, in this case MCO towards a bottom
contour, i.e.
BCO, where various methods are known in the art.
Since the drilling pattern of the maximum contour MCO does not encompass the
full
face contour FC, and thereby not the total volume that is to be drilled and
blasted
during the round to be drilled, additional drill holes are added in a similar
manner for
the remaining portion of the face contour, i.e. represented by MC1, MC2, for
which
portions drilling patterns can be generated in the same manner, where the
drilling
pattern for portion MC1 will be generated towards intermediate bottom contour
BC1
instead of bottom contour BCO. Similarly, the drilling pattern will be
generated for
contour MC2 towards the second intermediate bottom contour BC2.
That is, for each of the contours MCO, MC1 etc. the portion of the drilling
pattern to
be generated for this particular part of the face contour can be seen as a
generating
a conventional drilling pattern from a part of the face contour towards a
bottom
contour. Hence, according to the present example, three different drilling
patterns can
be generated and aggregated to a single drilling pattern.
The drilling pattern for the various contours/bottom contours may also be
generated
in any suitable order, for example starting with the longest holes to be
drilled, i.e.
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towards the bottom contour BCO. However, when generating the drilling pattern
for
border portions of the contours MCO, MC1, MC2 there may arise an overlap
regarding holes to be drilled i.e. holes for the different portions of the
face contour
may be determined to be drilled too close to each other. For example, the
system
may be set such that a minimum distance is to be maintained between holes to
be
drilled. Therefore, when generating the drilling pattern, holes considered to
cover
portions of the face contour FC for which a drilling pattern has already been
generated may be disregarded. For example, holes of a longer length may be
arranged to be maintained. Alternatively, shorter holes may be maintained over
longer holes.
When drilling patterns have been generated for the bottom contour BC and the
intermediate contours BC1, BC2, an aggregate drilling pattern covering the
full face
contour FC have been generated. The aggregate drilling pattern may then be
drilled,
where holes may be drilled in any order, step 307. Following drilling the
method is
then ended in step 308.
As was mentioned above, e.g. the angular direction of the holes to be drilled
can be
used when defining the different contours MCO, MC1, MC2, but other criteria
may
also apply. For example, input parameters to the generation of the drilling
pattern
may include a minimum width and/or height of each portion of the face contour
that is
to be drilled towards a specific bottom contour. Similarly, this may be used
to
determine a number of intermediate bottom contours to be used. It is, for
example,
contemplated that an iteration is performed where an initial number of bottom
contours are generated and on the basis of this the contours MCO, MC1, MC2 are
generated, and if these are considered small or too large, the number of
intermediate
bottom contours may be increased or decreased.
The invention may be utilized to generate drilling patterns that following
drilling and
blasting generates a cavity having a high correspondence with the cavity set
up to be
drilled. The invention may further be utilized in situations where there are
substantial
changes with regard to the profile of the cavity presently being drilled. This
is
illustrated in FIG 13, which illustrates a tunnel that is about to divide into
two separate
sections 1301, 1302. Similar to figs. 6A-B, fig. 13 discloses the face contour
FC of the
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rock to be drilled and a bottom contour BCO and intermediate bottom contours
BC1,
BC2. The use of a plurality of bottom contours according to the invention
allow, as
according to the present example, drilling of one tunnel section 1301 to be
commenced while with regard to the other tunnel section 1302 shorter holes,
limited
by intermediate contour BC1, may be drilled so that the portion 1303 that is
to remain
and separate the tunnel section from each other may be maintained to as high
extent
as possible while the round to be drilled may still excavate as much as
possible of the
common portion of the tunnel.
Fig. 14 illustrates an alternative method for dividing the face contours into
portions to
be drilled towards different bottom contours. According to the disclosed
example, the
number and location of the bottom contours may be determined beforehand and
projection of the bottoms contours onto the face contour FC may be utilised to
establish the portions MCO, MC1, MC2. Fig. 14 illustrates a situation where
the tunnel
is narrowing, i.e. the tunnel/cavity is transitioning from a wider section to
a narrower
section. The maximum contour MCO is defined by projecting the bottom contour
BCO
onto face contour FC. This is illustrated by line 1402, which represents
projection of
the bottom contour BCO onto the face contour FC and results in a maximum
contour
MCO having the smaller width indicated by line 1404 in the figure. Similarly,
the
portions MC1 and MC2 of the face contour FC can be determined by projecting
the
bottom contours BC1 and BC2 onto the face contour. A drilling pattern may then
be
generated according to the above.
Finally, for the sake of simplicity, the bottom contours BCO, BC1, BC2 have
been
illustrated as at least essentially planar surfaces. This need not be the
case, but any
of or all of the bottom contours may take any desired shape.
Furthermore, according to embodiments of the invention, limitations imposed by
the
already excavated portion of the tunnel regarding manoeuvrability of the rear
end
209B, 210B, 211B of the feed beam 209-211 can be taken into account when
generating the drilling pattern. The tunnel walls of the already excavated
portion of
the tunnel will impose restrictions on possible manoeuvring of the feed
beam(s) of the
drilling rig so that holes that would be desired to drill from an excavation
point of view
e.g. to reduce the amount of surplus rock being excavated may not in reality
be
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possible to drill due to feed beam manoeuvring limitations, which may render a
required manoeuvring of the feed beam in order to drill the holes according to
the
determined drilling pattern impossible. This may be the case, for example,
when the
cavity to be drilled is narrowing, and/or when cavity is not following a
straight line.
5 Hence, according to embodiments of the invention, a drilling pattern may
be
generated that will also be drillable, and that may not be subject to
manoeuvring
difficulties due to surrounding rock being unaccounted for. In this way it can
be
ensured that rock is excavated to an extent sufficient to provide the desired
cavity
while simultaneously breaking of surplus rock may be reduced by creating a
drilling
10 pattern that take the actual conditions prevailing at the location of
the rock face
regarding manoeuvrability of the feed beam into account to thereby create a
drilling
pattern that may result in less surplus rock being excavated than otherwise
might be
the case.
Fig. 5 illustrates a method 500 where this is taken into account. Steps 501-
503 are
15 similar to steps 301-303 in fig. 3, and are therefore not described more
in detail.
In step 504 a further contour, a limiting contour LC, is established. The
limiting
contour LC is also interpolated using adjacent tunnel line contours, TLn-2,
TLn-1, in a
manner similar to the above at a distance from the face contour FC, and in a
direction
from the face contour FC opposite the drilling direction. The limiting contour
is
20 illustrated in fig. 6C, which otherwise is similar to fig. 6A. The
distance between the
face contour FC and the limiting contour LC may, as in the present example,
e.g. be
selected to equal the length of the feed beam of the drilling rig, but the
distance may
also be any other suitable distance. According to the present example, the
limiting
contour LC is used to take surrounding rock of the already excavated portion
of the
25 tunnel into account to determine drillability of the holes when
determining the drilling
pattern so that the manoeuvrability of the feed beam is taken into account.
The limiting contour LC may be interpolated using tunnel line contours as
above, but
if a scanned representation of the actual rock wall of the already drilled
portion of the
tunnel is available this can be used instead to increase accuracy when
determining if
holes are drillable or not. Also, for example, the rear end of the feed beam
may be
manoeuvred to the extreme positions, e.g. left, right, top, bottom, bottom
right, top left
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etc. and thereby establish a representation of the cavity at the end of the
feed beam.
Furthermore, the limiting contour LC may be selected such that it's normal
vector
coincides with the direction of navigation and hence the limiting contour LC
is parallel
to the face contour FC.
In step 505 a first maximum contour MCO is generated. This maximum contour MCO
represents the maximum possible portion of the face contour FC where it is
possible
to drill the holes having the maximum length being drilled during the current
round of
drilling, while ensuring manoeuvrability of the feed beam. The maximum contour
MCO
is arranged to be in the navigation plane NP, i.e. the same plane as the face
contour
FC. The boundaries of the maximum contour MCO is limited by the periphery of
the
face contour FC, since this is the maximum surface to be drilled, but MCO is
also
delimited by a 3D-interpolation using the limiting contour LC and the bottom
contour
BCO in the plane of the face contour FC. This is illustrated in FIG. 7 by
dashed
interpolation lines 701 and 702. The resulting contour MCO, delimited also by
the
face contour FC, is shown as the hashed area of fig. 8, which hence shows the
face
contour FC and the determined MCO. The area MCO, consequently, represents the
portion of the face contour FC that may be drilled with full-length holes when
drilling
the next round. The area resulting from the interpolation that is located
outside the
face contour FC, i.e. the hashed area 801, is disregarded since this area is
not to be
drilled.
When the maximum contour MCO has been determined according to the above, a
drilling pattern is generated, step 506, for the maximum contour MCO, which
hence
constitutes a drilling pattern of holes to be drilled from face contour FC to
the bottom
contour BCO. The drilling pattern of the maximum contour MCO can be generated
according to the above. The drilling pattern may alternatively, as above, be
generated once all contours have been established. The drilling pattern of
maximum
contour MCO will not, as discussed above, represent the total volume that is
to be
drilled and blasted during the round to be drilled. Additional drill holes
must be added
in order to drill the full volume. Therefore, the remaining portion of the
face contour,
i.e. the non-hashed portion of fig. 8, shown as hashed in fig. 9 and denoted
DC, is
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still to be drilled, using holes having a length being less than the maximum
length of
the holes of the round to be drilled may be used for this portion of the face
contour.
In step 507, therefore, the difference surface, contour DC, constituting the
difference
between the face contour FC and the maximum contour MCO is determined. With
regard to this surface, a drilling pattern is to be generated where holes are
drilled to a
shorter length than holes being drilled when drilling the generated drilling
pattern of
the maximum contour MCO.
According to embodiments of the invention, it is determined a number of rows
of
holes to be drilled on the difference contour DC. This can be established, for
example
using rules regarding distance between holes to be used when generating
drilling
patterns, where this distance can be dependent e.g. on the properties of the
rock to
be drilled, diameter of holes to be drilled, length of the section of rock
that is about to
be excavated in the current round etc., as is known per se. This determination
regarding the holes, however, is oftentimes already performed, and is
therefore not
part of the invention. Hence, when e.g. the applicable hole distance is
established, a
number of rows of holes to be drilled in the difference contour DC may also be
determined.
The determined number of rows of holes to be drilled, and/or alternatively the
width of
the difference contour DC, is then used to establish a number n intermediate
bottom
contours BC1...BCn, step 507, to be used between the face contour FC and the
original bottom contour BCO. That is, according to the present example, the
intermediate bottom contours are determined in a different manner in
comparison to
the above. For example, one bottom contour can be generated for each, e.g.
vertical
or horizontal, row of holes to be drilled in the difference contour DC. The
intermediate
bottom contours BC1...BCn can be generated in the same manner as BCO above,
i.e. through interpolation using the tunnel contours of the adjacent tunnel
line points.
With regard to the location of the bottom contours BC1...BCn, these can be
arranged
to be evenly spaced between the face contour FC and the bottom contour BCO.
That
is, for example, if only one additional drilling pattern is to be generated,
the additional
bottom contour BC1 can be arranged to be positioned at half the distance from
the
face contour FC to the bottom contour BCO. The distances to the additional
bottom
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contours/planes may also be determined in any other suitable manner, e.g. in
dependence of the curvature of the cavity to be drilled.
According to the present example, two additional bottom contours BC1, BC2 are
generated, which are evenly spaced between the face contour FC and the bottom
contour BCO. This is illustrated in fig. 10, where the two intermediate planes
BC1,
BC2 are shown. Other distributions than even distances between contours may
also
be utilised. A drilling pattern may then be generated for each additional
bottom
contour BC1...BCn, step 508, where the additional drilling patterns can be
generated
using the above described principle, by interpolating, respectively, the
additional
bottom contours BC1...BC2 and the limiting contour LC in the plane of the face
contour FC, and further delimit by the face contour FC. This is illustrated by
the lines
1001, 1002 used in the interpolation in fig. 10, and the portion to be drilled
to a hole
depth delimited by BC1 is schematically indicated as MC1 portion of DC in fig.
9, and
the portion to be drilled to a hole depth delimited by BC2 is schematically
indicated as
MC2 portion of DC in fig 9. Portions of the face contour FC for which drilling
patterns
have already been generated, e.g. MCO, are disregarded. Hence, when generating
a
drilling pattern for BC1, this will, according to the present example, render
one or
more further row of holes to be drilled, essentially having a length
corresponding to
the distance between the face contour FC and the intermediate bottom contour
BC1.
Again, holes regarding portions of the face contour FC for which a drilling
pattern has
already been generated are disregarded. Furthermore, holes being too close to
already planned holes, e.g. for the maximum contour MCO may also be
disregarded,
since the already planned holes in general will be holes of a longer length.
Alternatively, such holes may be omitted from the drilling pattern of MCO
instead.
When the drilling pattern for the first intermediate bottom contour BC1 has
been
generated, a drilling pattern is generated for the second intermediate bottom
contour
BC2 in a similar manner, which in this example will render one or more further
row of
holes to be drilled, essentially having a length corresponding to the distance
between
the face contour FC and the second intermediate bottom contour BC2, i.e. holes
having a yet shorter length. In addition to holes regarding portions of the
face contour
FC for which a drilling pattern has already been generated with respect to the
bottom
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contour BCO, holes of the drilling pattern for the first intermediate bottom
contour BC1
may be disregarded, and also holes being too close to already planned holes as
discussed above.
When drilling patterns have been generated for the bottom contour BC and the
intermediate contours BC1, BC2, consequently, an aggregate drilling pattern
covering the full face contour FC have been generated, and fig. 11
schematically
illustrates the holes to be drilled by solid lines extending from the face
contour FC to
the bottom contours, respectively. The aggregate drilling pattern may then be
drilled
one at a time or be treated as a single aggregated drilling pattern, step 509,
where
holes may be drilled in any order and not just one drilling pattern at a time.
The
method is then ended in step 510. Again, the drilling pattern for the various
parts of
the face contour may instead be generated once all contours have been
established,
i.e. similar to the exemplary method of fig. 3.
The drilling patterns regarding the different bottom contours may also be
generated in
any other order, still for the same areas, but shorter holes may be maintained
instead
of longer holes in the border areas should this be considered advantageous,
e.g. to
reduce surplus rock. Also, the different portions MCO, MC1 etc. may be
determined
prior to the actual drilling patterns are being determined.
Furthermore, according to embodiments of the exemplary method of fig. 5, the
areas
of the face contour FC not covered by the maximum contour MCO may be enlarged,
i.e. the area of MCO may be reduced. This may be carried out e.g. in order to
make
room for one or more further rows of holes in case the difference contour is
determined to be too small, e.g. being too narrow. Such parameters may be pre-
set
in the control system.
Enlargement of the difference area may be accomplished by reducing the size of
the
maximum contour MCO. For example, the limiting contour LC can be projected to
the
face contour FC in the navigation plane, instead of utilising interpolation,
thereby
further limiting the size of the maximum contour MCO. This is exemplified in
fig. 7 by
dotted line 710, which hence renders the maximum contour MCO smaller, thereby
increasing the area to be drilled using shorter hole lengths.
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The projection may be used in combination with interpolation according to the
above,
but projection may also be utilised instead of the interpolation. That is, for
example,
only the limiting contour LC or a bottom contour BCO may be used in the
establishment of the maximum contour MCO /difference contour, e.g. as
discussed
5 with reference to the method of fig. 3, and e.g. projection according to
fig. 14 may be
utilised.
This is illustrated in fig. 12, which is similar to fig. 14, but where the
line 1201
exemplifies interpolation according to the above, which results in a maximum
contour
MCO having a width corresponding to line 1203.The maximum contour MCO can be
10 reduced by projecting the bottom contour BCO onto face contour FC
instead of
utilising interpolation, line 1202 to increase the part of the face contour FC
for which
holes having a reduced length are to be drilled, the increase of the
difference
contour, i.e. reduction of the maximum contour MCO, being indicated by line
1205.
Furthermore, the method for generating a drilling pattern has been described
above
15 as being carried out by a drilling rig that is present at a location
where a rock face is
about to be drilled. According to embodiments of the invention, the generation
of the
drilling pattern may be carried out by a computer e.g. in a planning centre,
where e.g.
a drilling pattern may be generated for any location of the cavity to be
drilled, so that
personnel e.g. may evaluate the generated the drilling pattern, and adjust
input
20 parameters to be used in the generation of the drilling pattern.
