Note: Descriptions are shown in the official language in which they were submitted.
s
THIS INVENTION relates to improved dragline
apparatus suitable for mining or excavating purposes and
method of use of same~
Conventional draglines include a dragline housing
which incorporates a hoist winch, an outwardly extending
boom carrying a hoist cable connected to the hoist winch
which may extend downwardly from an outer end of the boom
attached to an excavator bucket as hereinafter described and
a drag cable attached to the excavator bucket which is
connected to a drag winch located in the dragline housing.
Both the drag winch and hoist winch are suitably driven from
electric motors and the dragline housing is suitably
rotatably mounted to a support base by a central bearing~
The dragline housing may be equipped with crawler tracks for
locomotion or alternatively and more commonly is equipped
with a walking mechanism having a pair of support feet which
are reciprocatable relative to the dragline housing and thus
may propel the dragline housing in a desired direction o~
travel.
The excavator bucket is usually arcuate in shape
having a base and upper side wall provided with an open
front or access mouth whereby soil or overburden may gain
access to the interior of the bucket as the bucket is
dragged or moved through loose overburden by the drag
cable(s). A plurality of ripper teeth along a free edge of
the base may be provided in the open front or access mouth.
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~8~35
The rear end of the excavator bucket is provided
with a pair of opposed support chains each attache~ to a
respective support lug on the external face of the upper
side wall. The chains may be interconnected by a horizontal
bar. The hoist cable(s) may be split into two hal portions
or hoist cable components wherein each component is attached
to an associated end of the horizontal bar.
There also may be provided a support loop adjacent
the open front of the bucket to which may be attached
further cable(s) connected to the hoist cable~s) and also to
the drag cable(s) by use of an appropriate sheave
mechanism. There also may be provided a pair of drag chains
attached to each front vertical edge of the upper wall which
are each attached to the drag cable(s).
The abovementioned conventional dragline operates
to remove overburden or to mine a mineral from a valuable
mineral or coal deposit such as a coal seam. After
initially drilling and blasting the overburden by a suitable
explosive such as ammonium nitrate, the overburden is
loosened and softened. A bulldozer was then used to level a
portion of the overburden to provide a flattened hill for
supporting the dragline housing. The excavator bucket was
then moved to the desired location wherein the drag winch
was free spinning so that the drag cable was slack. In this
movement the hoist winch has enough tension to hold the
- excavator bucket as it swings freely when suspended from the
boom. Then the excavator bucket is placed on the ground by
actuation of the hoist cable and tension is subsequently
applied to the drag cables. The bucket is subsequently
dragged through the loose overburden until it is full. The
tension is then maintained in the drag cables and tension is
applied to the hoist cables to elevate the full bucket above
the overburden. By balanced control of the hoist winch and
drag winch the bucket may then be moved towards the top of
the boom which has a sheave for supporting the hoist cable,
The dragline housing is then rotated away from the
excavation site towards a spoil pile or dump from the
overburden in the bucket and is tipped out o~ the excavator
bucket by slackening of the tension in the drag cables. By
appropriate control of the hoist cable the empty excavator
bucket then assumes its normal orientation and is then moved
back to the excavation site by rotation of the dragline
housing.
The abovedescribed conventional dragline apparatus
had several disadvantages and one major disadvantage was
that it was constrained by yeometric or physical size
parameters such as the length of the hoist cable and drag
cable(s) and/or the length of the boom excavation site.
Thus for example, if a coal seam was too deep for the cables
then "rehandling operations" were necessary wherein material
already removed or dug by the excavator bucket is dug again
by auxiliary or companion excavation equipment such as a
bucket wheel excavator or repositioning o~ the dragline.
Thus in relation to a particular mine if the coal seam was
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too deep ~or the physical parameters of the machine it was
necessary to carry out a prestripping operation by truck and
shovel, bucke-t wheel excavator or scraper to remove the top
level of overburden. Rehandling or prestripping operations
were found to be very expensive in practice and insufficient
in relation ~o the depth of the open cut excavation site.
Thus in other words, as the depth increased, there was a
tendency for the spoil pile and high wall excavation
material separating the excavation site and the flat-tened
hill supporting the dragline housing to subside and fall
into the open cut excavation site.
It therefore is an object of the invention to
provide a dragline apparatus and method of use which may
alleviate the abovementioned disadvantages associated with
the prior art.
The method of the invention is a method of
excavating overburden from a mineral or coal deposit seam
using a low wall winch component, a high wall winch
component and a hoe wherein the hoe is attached to the low
2~ wall winch component by one or more draglines and the hoe is
attached to the high wall winch component by a tail line
including the following steps:
~i) moving the hoe by tensioning of the draglines by
the low wall winch component through overburden
created by preliminary drilling and blasting to
move said overburden away from the mineral or coal
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6.
deposit seams in one or more traverses wherein
overburden is loaded onto the hoe and subsequently
dumped onto a spoil bank; and
~ii) moving the hoe at the end of the or each traverse
back to the starting point of the traverse b~
untensioning of the draglines by the low wall winch
component and tensioning of the tail line by the
high wall winch component.
The invention also includes within its scope
dragline apparatus for carrying out the aforementioned
method including~
(A) a low wall winch component comprising ~
a housing;
a boom extending outwardly from the housing for
supporting one or more draglines;
winch means for rotatably carrying said one or more
draglines;
drive means for actuating movement of the winch
means; and
traversing means supporting the housing.
(B) a high wall winch component comprising -
a housing;
a boom extending outwardly from the housing for
supporting a tail line;
winch means for rotatably carrying said tail line;
drive means for actuating movement of the winch
means; and
traversing means supporting the housing, and
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7.
~C) an excavating hoe attachable to said one or more
draglines at one end and said tail line at another
end.
The terms "high wall" and "low wall" as used herein
refer to the opposing slopes or walls of an excavation site
wherein one wall is of greater height (ie. the high wall)
than the other wall (ie. the low wall) before mining takes
place.
The high wall winch component may include a single
winch drum operated by appropriate drive means although a
set of in line winch drums could be used i necessary. The
winch drum(s) may he mounted by a movable housing which also
may have an outwardly extending boom for supporting a high
wall cable. The boom may have a free outer end to which a
pulley or sheave is attached for control of the high wall
cable. A suitable drive means for the winch drum may
include a series of drive motors drivingly connected to the
winch drum by appropriate gearing means or bearing means. A
suitable source of electricity supply such as a generator or
the like may be provided for providing power to the electric
motors. However, it will also be appreciated that external
power from the mains may be used for providing power to the
electric motors.
The housing is suitably rotatably mounted to a
suitable support base and in one form this may include the
housing mounted to a central bearing of the support base.
There also may be provided a swing rack or rack of round
-
shape which may meshingly engage with a 5uitable drive motor
by appropriate gearing or bearing means.
The housing may also be equipped for movement in
any desired direction and in one ~orm the housing may be
moved by a pair of reciprocatable feet as described below
for the low wall winch component. However, more preferably,
the housing is supported by a pair of opposed crawler
tracks.
The low wall winch component if desired may be
similar in construction to the high wall winch component as
described above. However, more suitably, the low wall winch
component includes a pair of in line winch drums although a
single winch drum may be used in some circumstances. Each
winch drum may be driven by suitable drive motors as
described above. There also may be provided a housing for
supporting the winch drum(s). There also may be provided an
outwardly extending boom for supporting one or a plurality
of low wall cables. To this end the boom may have an outer
end to which is attached one or a plurality of opposed
sheaves or pulleys for controlling a respective low wall
cable. The housing may also have a suitable source of
electric supply or use external power as described above and
be provided with traversing or moving means such as a pair
o~ crawler tracks or more suitably a pair of traversing feet
which operate in a similar manner to a conventional dragline
apparatus as described above.
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The housing may also be rotatably mounted on a
suitable support base in a similar manner as described above
for the high wall winch. Thus there may be provided a
central bearing or pintle bearing interconnecting the
housing and the support base. There also may be provided a
swing rack as described abov~ driven by one or more
preferably a plurality of drive motors. The swing rack may
be welded or rigidly attached to the support base.
There also may be provided auxiliary support means
in the form of bearing rollers interconnecting mating
abutments of the support base and the housing.
When it is required to move the low wall winch
component, the housing may be rotated to face in a direction
opposite to the desired direction of travel and the feet are
suitably located on opposed sides of the housing and
reciprocate in an associated slot. The feet may then move
rearwardly and drag the support base in the direction of
travel. The operation may be operated by a pair of
pantograph links or alternatively is cam operated.
The excavator implement for use in the invention
may be of any suitable type such as a bucket having an open
top and open front. Preferably, however, the excavator
implement is an e~cavating hoe including:
a body portion suitably of imperforate type;
a blade portion extending downwardly from the body
portion and hingedly attached thereto; and
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a pair of opposed side members attached to or
intergral with the body portion and adapted for
later~l scraping of overburden;
first attachment means for one or more draglines;
and
second attachment means for a tail line.
There is now shown and illustrated in the attached
drawings a preferred embodiment of the invention. In the
- drawings:
FIG 1 represents a side elevation of a high wall
winch component constructed in accordan~e with the
invention;
FIG 2 represents a plan view of the high wall winch
component shown in FIG 1;
FIG 3 represents a side elevation o~ a low wall
winch component constructed in accordance with the
invention;
FIG 4 represents a plan view of the low wall winch
component shown in FIG 3;
FIGS 4A and 4B represent two alternative mechanisms
for walking means suitable for the low wall winch component;
FIG 5 represents a perspective view of the
excavator hoe;
FIGS 6A, 6B and 6C represent varying views of the
excavator hoe;
FIG 7 represents a perspective view of a low wall
winch component for use in the method of the invention;
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FIGS 8, 9 and 9A represent open cut drawings
illustrating various aspects of the method of the invention;
FIGS lOA, lOB and lOC represent schematic side
views illustrating the method of excavation shown in FIG 8;
and
FIGS llA, llB and llC represent schematic side
views illustrating the method of excavation shown in FIG 9.
In the high wall winch component 9 shown in FIGS
1-2 there is included housing 5, boom attachment cables 7,
attachment cable support brackets 6 located on housing 5,
attachment cable brackets 8 associated with boom 15, winch
drum 10, drive motors 11 for actuating rotation oE winch
drum 10, electrical supply 12, circular swing rack 13,
crawler tracks 14, sheave or pulley 16 and tail cable or
line 17. For conven.ience the drive means for effecting
rotation of housing 5 is shown in the low wall winch
component shown in FIGS 3-4. The boom 15 is pivoted to
housing 5 at 17A and may easily be retracted or extended as
desired by engagement or disengagement of support cables 7.
Also shown is control cabin i6A.
In the low wall winch component 8 shown in FIGS 3-4
there is included housing 8A, a pair of winch drums 18
driven by drive motors 19, electrical supply 20, centre
pintle bearing 21, support base 23, boom 24, sheave or
pulley 25, drag cables 26A and 26B respectively and electriC
motor 27 fo.r effecting rotation of swing rack 28. As shown
is motor 27 which through gearbox 27A has drive shaft 27B
which has pinion 27C which meshes with swing rack 28.
12.
Also shown is walking members 22 as well as ventilation box
28A and control cabin 28B. The boom 24 is pivoted to housing
8A at 26C and also at 26D. There is also shown actuating
mechanism 22A for effecting elevating and lowering of
members 22 which is shown in more detail in FIGS 4~ and 4B.
The actuating mechanism 22A for effecting raising
and lowering of walking members 22 may be one of two
alternative types as shown in FIGS 4A and 4B.
In FIG 4A the walking member 22 is provided with
lug 28A having cam follower 28B attached to cam 28C. Cam
28C has an axle (not shown) collinear with pin 29A. As cam
28C rotates and thus causes corresponding movement of
follower 28B this causes support member 29B to slide in the
slideway 29C and thus base 23 while off the ground moves
forwardly relative to walking members 22. The base 23 is
then placed on the ground when the pin 29A has p~ssed the
apex of its motion and at the same time walking members 22
are on the ground. Subsequently walking members 22 are
lifted off the ground and move relative to base 23 and then
are placed on the ground in an advanced location. While
this cam and slide walking mechanism is described only
schematically in FIG 4A, this is a conventional mechanism
and is illustrated more comprehensively in a publication
entitled "Sur~ace Mining Machinery" by Bucyrus-Erie Company
in the U.S.A.
In FIG 4B another suitable walking mechanism is
illustrated wherein there is provided a pin 24B
reciprocatable in a slot 25A. The pin may be attached to
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a crank 24C which may also engage with an axle 23A rotatably
mounted on housing 8A. The pin may also be attached to the
periphery of a cam (not shown) which is driven by drive
motors 25C shown in FIG 4. As the pin 24B moves downwardly
towards the end of slot 25A this will lift base 23 off the
ground relative to walking members 22 which are stationary.
As the pin 24B approaches the top end of slot 25A this in
turn will lift walking members 22 up and then down a
distance in advance of their original position. Also shown
is support structure 23C containing slot 25A. Again this
walking mechanism is a conventional one and illustrated in
the aforementioned publication.
The excavating implement or hoe 29 is shown in FIGS
5, 6A, 6B and 6C and includes a body frame 31 which may have
a ballast support 30 overlying same as shown. Body frame 31
includes tranverse members 31A and longitudinal members 31B
as best shown in FIG 6C. There is also included downwardly
oriented scraper blade 33 which suitably is of waffle
construction as shown in FIG 5 comprising vertical
20 reinforcement members 33A and horizontal reinforcement
members 33B. Scraper blade 33 is pivotally attached to body
frame 31 at 34~ There is also provided opposed locking
aperture 34A, scraper blade 33 and corresponding locking
aperture 34B on body frame 31 which may register as shown in
25 FIG 6B and be locked by a locking pin to enable the hoe 29
to be hauled back for maintenance purposes without
collecting a load by drag cables 26A or 26B or tail cable
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14.
Scraper blade 33 is provided with earth ripping tynes 39.
Drag cables 26A and 26B may pass through guide channels 38
of ballast body 30 which also has top surface 39A wherein
earth may be placed on top of ballast body 30 if required to
assist in dragging the hoe 29 through the excavation. Body
30 may also be provided with a continuous peripheral ~lange
30A. Body frame 31 is also provided with retaining spikes
35 to assist in retention of scraped earth under scraper
blade 33. Drag cables 26A and 26B are attached to scraper
blade at 32 and there is also provided bracket 36 to which
tail rope 17 is attached.
In FIGS 6A, 6B and 6C there is also shown skid
member 38B having a smooth undersurface which is attached to
drag cables 26A and 26B by attachment bracket 38C. Also
shown is support brackets 38A for drag cables 26A and 26B
and support tracks 38D as best shown in FIG 6B. Also shown
are side scraper members 32A having reinforcing fillets 32B
which may be bolted to body frame 31 by bolts 31A engaging
through attachment apertures 32C.
The important features of the hoe shown in ~IGS 5,
6A, 6B and 6C as described above include the following:
(a) the inclusion of bod~ frame 31 which also may
include a perforated plate or mesh sheet within its
scope ensures that the hoe 29 "floats" on the
contained load when filled and prevents the load
"working". The inclusion of body frame 31 will
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15.
reduce the incidence of material lying on ~op of
hoe 29 as well as pxoviding better "bite" on the
retained load,
(b) the inclusion of ripping teeth 39 will enable the
hoe 29 to rip overburden if required,
(c) the hoe blade 33 is designed to trap some
overburden during the return trip,
(d) the inclusion of the pivoted or hinged blade 33
provides efficient collection of overburden during
dragging operations.
FIG 7 shows the low wall winch in much greater
detail and dragging hoe 29 through overburden. The drag
cables 26A and 26B may be passed through frame 22C mounted
on top of housing 8A. Suitably the walking members 22 will
5 propel the low wall winch component 8A forward.
In the mining excavations shown in FIGS 8-9 the
operation of the dragline apparatus of the invention is
illustrated in combination with a conventional dragline.
There is shown a prestrip zone 41, upper level 42 which may
2~ represent an area still to be mined, drilled area 43 having
a plurality o drilled holes for insertion of an explosive
by apparatus 43A and conventional dragline 44 mining the
overburden over coal seam 46. Dragline 44 excavates as
described previously by creating a spoil pile 47. ~owever,
coal seam 46 was present at a lower level than dragline 44
could reach hence it was necessary to create prestrip area
or bank 41.
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16.
FIG 8 also shows an excavator hoe 29 being pulled
through overburden in zone 51 that has just been subjected
to blasting aft;er being drilled. The hoe 29 is dragged
through the overburden by drag cables associated with low
wall winch component 8. At the end of one pass, it is then
pulled back to the desired location by the tail cable
associated with high wall winch component 9. Excavated area
or spoil bank 48 has been created by the dragline apparatus
of the invention as well as zone 41 and FIG 8 shows the
dragline apparatus of the invention working its way upwardly
as shown to clear a prior spoil pile 47A created by a
conventional dragline. Area 53 has been stripped previously
by a conventional dragline. There is also shown prior spoil
bank 52 which is deeper than spoil bank 48. Also shown is
mined area 49 and access road 50.
FIG 9 shows the application of the dragline
apparatus of the invention to multi-level coal saams 46A and
46B. Conventional dragline 44A is now excavating overburden
over lower se~m 46B creating the usual spoil pile 47. Also
shown is the dragline apparatus of the invention represented
by apparatus 8, 9 and 29 removing dragline spoil piles 47B
and 47C. Dragline 44B is shown which has created spoil pile
47B. Spoil pile 47C was created by dragline 44A on a
previous strip.
FIG 9A shows a modified method of the invention
wherein initially overburden is throwblasted at 51 and then
the dragline apparatus of the invention may be utilized to
17.
mine seam 48A by creation of spoil bank ~8 as describe~
before. In this method use of the conventional dragline is
not required.
FIGS 10A, 10B and lOC show the operation of the
dragline apparatus of the invention in relation to a single
level coal seam 46. In FIG lOA a part of coal seam 46 is
exposed having been mined by a conventional dragline
creating spoil pile 47. The original level 51 is shown in
phantom as well as drilled area 43.
In FIG 10B low wall winch component 9 in
combination with high wall winch component 8 and hoe 29 is
being used to reclalm the dragline spoil represented by pile
47. The slope angle of spoil bank 48 is preferably lower
than the slope angle of spoil pile 47 (ie. 34 degrees
compared to 37 degrees). Prestrip zone 41 is also created
by apparatus 8-9 as well as the initial construction of
dragline bridge 54.
In FIG lOC the dragllne apparatus of the invention
is used to cut a key cut 55 whereby the excavated material
cut therefrom is deposited on the bridge 54. The bridge 54
is used to support a conventional dragline 44 as shown which
is then utilised to uncover coal seam 46.
In relation to multiple coal seam mining as shown
in FIGS llA, llB and llC conventional dragline 44B is used
to chop cut ahead as shown in 56 in FIG llA and then side
cast or take overburden to uncover coal seam 46A and dump
the overburden on spoil pile 47B.
18.
In FIG llB after mining of coal seam 46A the
dragline apparatus of the invention is then used to excavate
the conventional dragline spoil as described previously in
FIG 9 to create spoil bank 48 and also to initially
construct dragline bridge 54 as described in FIG 9. The
overburden is then stripped by conventional dragline ~4A as
shown in FIG llC wherein a chop cut 56 is made and the
bridge 54 is completed. The overburden over lower coal seam
46B is then removed and spoil pile 47 is then started in the
usual manner.
It will also be appreciated from the foregoing that
the dragline apparatus of the invention may be used without
the conventional dragline 44 in mining operations if
desired. It will also be appreciated that the invention not
only covers the improved dragline apparatus but also the
method of excavation using same described herein.
The term "low wall" as used herein refers to the
side or wall of the excavation where the coal has been
previously removed. The opposite side of the excavation is
referred to as the "high wall". In FIG llB the Iow wall
appears to be higher than the high wall due to the swelling
effect of loosened overburden and this may often occur in
practice during an excavation of a sloping coal seam.
The dragline apparatus of the invention may also be
used to shift overburden pxeviously shifted trucks and
shovels, crushers, conveyors, dredges and pipelines.
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In regard to the preferred embodiment of the
invention, it will be appreciated especially in regard to
FIGS 8, 9, lOA-,lOC and llA-llC that the dragline apparatus
of the invention may carry out the following steps:
5 (il it loosens some forms of in site overburden;
(ii) it transports the overburden horizontally over
varying dis~ances, and
~iii) elevates the overburden through varying heights.
In further variation of the above it will be
appreciated that there could be employed a plurality of high
wall winches (eg. two) to drag the excavating implement.
Also the dragline apparatus of the invention will
be found advantageous in reducing geotechnical problems
associated with the slope angle of spoil banks and reduce
the cost of removing overburden.
