CA1064528A - Open pit mine - Google Patents
Open pit mineInfo
- Publication number
- CA1064528A CA1064528A CA257,637A CA257637A CA1064528A CA 1064528 A CA1064528 A CA 1064528A CA 257637 A CA257637 A CA 257637A CA 1064528 A CA1064528 A CA 1064528A
- Authority
- CA
- Canada
- Prior art keywords
- turning point
- mined
- floor area
- mineral materials
- pit floor
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired
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- Excavating Of Shafts Or Tunnels (AREA)
- Disintegrating Or Milling (AREA)
Abstract
ABSTRACT OF THE DISCLOSURE
An improved open-pit mining method provides one or more working faces for breaking out the minerals and rock, the face advancing either horizontally or along a helical spiral path.
A turning point area is provided, usually at the center of the open pit where the faces extend radially from the turning point, enabling crushing equipment adjacent the benches to feed a belt conveyor system by which crushed mined mineral is conveyed directly to the turning point area. The turning point area communicates with a shaft down which the conveyed mined mineral materials are discharged. The turning point area is mined in any way that keeps the floor horizontal, and such floor is maintained deeper than the benches. A plurality of downwardly-directed shafts may be provided for receiving different grades or qualities of mined mineral.
An improved open-pit mining method provides one or more working faces for breaking out the minerals and rock, the face advancing either horizontally or along a helical spiral path.
A turning point area is provided, usually at the center of the open pit where the faces extend radially from the turning point, enabling crushing equipment adjacent the benches to feed a belt conveyor system by which crushed mined mineral is conveyed directly to the turning point area. The turning point area communicates with a shaft down which the conveyed mined mineral materials are discharged. The turning point area is mined in any way that keeps the floor horizontal, and such floor is maintained deeper than the benches. A plurality of downwardly-directed shafts may be provided for receiving different grades or qualities of mined mineral.
Description
This invention relates to novel configurations of open pit mines and to methods of mining in open pit operations so that mobile crushing apparatus can be located adjacent the benches and the crushed mined mineral materials can be delivered from the crusher to a materials-handling and discharge point by means of a belt conveyor system. In one of the preferred embodiments, called the "screw~mining method", radial-rotating benches are established to move on a downwardly~sloping screw-shaped path.
In another embodiment, the radial-rotating benches move in a horizontal plane.
The screw-mining method comprises one or several benches 'i! which are positioned radially with respect to a turning point area about which they rotate, moving on a downwardly-sloping screw-shaped path. If the turning point is located adjacent the i -,r.
periphery of the mining field, mined mineral material may be ,~
removed from the turning point area by means of one or more conveyors. If the turning point is located at a central point in --~
the mining field, then one or more vertical or inclined shafts ~ ;
are located in the turning point area. Mineral material mined from the benches is hauled to these shafts where it creates a buffer in the haulage system. Mineral material of different quality may be deposited separately in different shafts (or conveyors). These mined materials are either blended during the emptying of these shafts or transported separately to some further destination through one or several horizontal and/or inclined tunnels. These tunnels connect the bottom of the shafts with the earth's surface.
~ .' .
In the case where several high benches are mined simultan-eously with one shaft or with one set of shafts, the slope of the 3~ floor, where equipment must stand and move near the shafts within the turning point area, may become quite steep. It is therefore more convenient to mine mineral material within this small area .: , .: . ~ ~ ' . .:. . - ` ' ~interior zone) not through benches which are moving on down-wardly-sloping screw-shaped paths, but with any method which allows the floor of the turning poi.nt area to be kept more or - less horizontal.
~ oth methods, as such and combined with equipment, are suitable for use in open pit mining for extraction or rock, ore and other mineral materials excavat:ed from the earth's crust.
:,`
During the last two decades, more than fifty plants which ` utilize a "mobile crusher-conveyor system" have been introduced in surface minin~ .in many countries. By crushing the rock or ore . ~ before hauling, this system replaces trucks with belt conveyors, : :
~ thereby permitting a conkinuous, almost fully-automated operation, ,. . .
~ with all of its attendant advantages. Compared with conventional i~ methods and equipment now used in surface mining, the mobile crusher-conveyor system is able to increase drastically man hour output, to reduce the power consumption and maintenance of hauling ~`1 equlpment, and thus to reduce the cost of operation significantly. ~ ~.
.3 Foggy weather or icy roads, which can make trucking extremely hazardous or even impossible, has no effect on belt conveyor haulage. However, plants with mobile crusher-conveyor systems , have been well adapted for open pit mines which operate only one fl bench and mine material of on].y one quality. When several benches are mined simultaneously with conventional methods, the open pit ~;
mines have a circular or elliptical shape. The use of a mobile crusher-conveyor system in such mines requires prohibitive invest-ment for belt conveyors. Furthermore, the mobile crusher-conveyor system does not have the flexibility which truck haulage offers.
Using trucks, material of different quality which must be mined in an open pit can easily be transported from any point in the mine to any different desirable destination. The inventions described -and clained in this specification are able to eliminate these difficulties and to obtain further advanta~es and objectives.
: - 2 -, ~.~.' .
` 1~6~5~1~
It is an object of this invention to make mining operations more efficient, permitting drastic cuts in manpower and in costs.
Another object is to provide an efficient method of mining where several benches can be mined simultaneously.
Another object is to permit the application of a highly i efficient and economic mobile crusher-conveyor system in mines where several benches can be mined simultaneously.
~ Another object is to provide a method of open pit mining ; with a mobile crusher-conveyor system which reduces the length of the belt conveyor. Compared with the circular or elliptical ~.
shape of the open pit now used in surface mining, the length of the belt conveyor is reduced by the methods claimed herein up to six times or even more.
Another object is to permit mining of mineral materials of -~
~ different qualities.
j~ Another object is to permit blending of mined material of different qualities in the mine.
Another object is to provide a buffer in haulage of mined mineral material located between the loading point on the benches and the point of final destination. It will make operation in transportation without costly interruptions and disturbance.
The above-mentioned objects will be evident from the -~
j~ '' ' ':
~ following description of the drawings, in which:
.
FIG. la is a cross-sectional view of a conventional surface mining method with conventional equipment;
; FIG. lb is a cross-sectional view of a conventional surface mlning operation using a mobile crusher-conveyor system;
FIGS. 2a and 2b are cross-sectional and plan views of a conventional open pit mining method with circular or elliptical ~ ;
multi-benches;
FIG. 3 shows a perspective view of the new mining method / oE this invention, called a "screw-mining method", with radial-16~6~5~3 rotating benches moving on a downwardly-sloping screw-shaped path, combined with a mobile crusher-conveyor sys-tem (one or more vertical and/or inclined shafts can be used with this method);
FIG. 4 shows a perspective view of the screw-mining method of this invention combined with the mobile crusher-conveyor system as it is presented in FIG. 3, but with theifollowing difference:
. the large exterior zone of the mining field is mined with radial-rotating benches which move on a downwardly-sloping screw-shaped path; the small interior zone located near the shafts within the turning point area is mined with any other mining method which allows the floor where equipment stands and moves to be kept horizontal; ~:
FIG. 5 is a perspective view of the screw-mining method combined with conventional equipment;
FIG. 6 is a perspective view of a mining method with ~ .
radial-rotating benches which move in a horizontal plane, combined with a mobile crusher-conveyor system;
FIG. 7a and FIG. 7b are cross-sectional and plan views of the methods shown in FIGS. 3, 4 and 5 applied to the mining of a .
hill or mountain with a bench rotation of 360 degrees, using a shaft and tunnel for transportation of mined material; ~:
FIGS. 8a and 8b axe cross-sectional and plan views of the methods shown in FIGS. 3, 4 and 5 with a bench rotation of less than 360 degrees, woxking without shaft and tunnel; the means of material transport are placed on the surface of th~ hill; .: -FIGS. 9a and 9b are cross-sectional and plan views of methods shown in E'IGS. 3, 4 and 5 applied for mining of a large ~ mining area with a short tunnel; after the mining field A is mined ; a new tunnel in the mining field B is built to mine material in this region; ' FIGS. lOa and lOb are cross-sectional and plan views of : _ 4 _ the methods shown in FIGS. 3, ~ and 5 where mining of ore and gangue of the mining field occurs with the same shaft or set of shafts; and : FIGS. lla and llb are cross-sectional and plan views of the methods shown in FIGS. 3, 4 and 5 where mining o~ ore and . gangue of the mining field occurs with a completely separate ` shaft or shafts and the horizontal and/or inclined tunnels associ-ated with them. .
In the drawings to be described more particularly in the following text, FIGS o 3 to 11 show a mining area having circular ::
shape, but it will be understood that an area can have other shapes. .;
The mining art prior to this invention may be seen by re~erring particularly to FIG. la where there is shown a cross- :
sectional view of a surface mining operation with conventional equipment. In hard roc~, bench 1 is blasted with explosives .
which fill borehol~2 drilled in this rockO Blasted material in .
a pile 3 is loaded by a loading machine 4 into a truck 5 which transports this material to a stationary crusher 6. Crushed material is transported to rock storage or to a treatment plant where raw ma~erial is converted into a commercial product. .~
FIG. lb shows a cross-sectional view of a surface mining ~.
operation where a mobile crusher-conveyor system is used. Here ; blasted material from pile 3 is loaded by a loading machine into ,, mobile crusher 7. Crushed material is cleposited by a swinging conveyor ~ which i.s attached to the mobile crusher 7 either onto ~; a bridge conveyor 9 or directly onto a stationary or semi-station-; ary conveyor 10. Conveyor 10 transports crushed material to . .
a rock storage or to a treatment plant.
FIG. 2a shows a cross-sectional view of an open pit mine and FIG. 2b shows the mine in plan. Mineral material mined from benches 1 moves from the middle pOillt 11 or middle axis of the , ~, ~ 5 -:~
6~52~
.
pit to the outside toward the limits of the mining field or ; towards the limits of the mineral deposit. ~he shape of the face of these benches 1 is mostly circular or elliptical, not easily adaptable for the use of helt conveyors which must be straight.
Transportation of mined material from benches 1, which lack direct exit due to the topography of the country, occurs through tunnel 12. To reach this tunnel 12, mined material is transported down from bench to bench which are connected with sloped roads 13. ,~
Even in the case when a group of two or three benches are operated with a single conveyor located on one of these benches and which is connected with other benches b~ means of bridge conveyors 9, such a pit would need many long, very expensive conveyors and bridge conveyors. The required investment for such installation would be prohibitive. Most of the open pit mines are hauling mineral material of different grandes separately from different loading points to several plances or to a point where ~;
mineral material of different grades is blended. This requirement would create serious difficulties for the mobile crusher-conveyor ~ system if applied to conventional mining methods now used in surface mining.
. The invention to which this specification is dixected permits all of the above-mentioned difficulties to be overcome in the best way. Compared to the circular or elliptical shape of bench faces, the total length of conveyors for a screw-mined pit will be six or more times shorter. The operation of such a mine ~;
also permits maximum efficiency in cases when blending of material extracted is required. Following one embodiment of this invention, the movement of a bench or bench faces takes place in the form of a downwardl~-directed "screw" or "spiral" and therefore this method of mining is referred to in this specification and the appended clalms as the "screw-mining method" or "spiral-mining method".
FIG. 3 shows a perspective view o~ a screw-mining method combined .
with a "mobile crusher-conveyor system".
The screw-mining method comprises one or several benches which may be mined simultaneously and are radially positioned ; with respect to a turning point area about which they rotate in a clockwise or counter-clockwise direction 21 moving on a downwardly-sloping screw-shaped path. Each bench 1 rotates many times around the turning point area 14 until it reaches its lowest desirable level which could be the bottom of the planned mining field. The development of a new bench 1 after each rotation of 360 degrees is therefore not required. The costs for development of a new bench and for the moving of all equipment from the old to the new bench are saved. inconveniences associated with the development of a new bench will not occur.
Depending upon the geological, mining and economic conditions one or several vextical or inclined shafts are located in the turning point area. When a mineral deposit dips into the earth's crust under a certain angle as it is shown in FIG. 4, it may be more advantageous to use an inclined shaft 22 instead of a vertical ~ ' one. An inclined shaft may permit the shaft opening, through which mined material is transported, always to be kept close to the center of a mining field. Therefore, one can use the same length length of belt conveyor placed parallel to the bench Eor the entire time.
The conveyor 10 is usually placed parallel to the bench 1 and the mobile crusher 7 is moved between the bench 1 and the conveyor ]0. Mineral material blasted with boreholes 2 is loaded from pile 3 by a :Loading machine 4 into the mobile crusher 7. A
mechanical shovel, front loader, or any other type of loading machine may be used in the system de.scribed. The crusher 7 discharges the broken material onto conveyor 10 which transports it to the turning point area 1~ where one or more vertical shafts lS or inclined shafts 22 or other means of transportation are located. Mineral material oE different ~ualities can be deposited :
4~
in different shafts. At the bottom of these shafts 15 and 22, min~d material is taken out by a feeder 16 and is either blended and transported through tunnels 18 and 20 to a further destination or transported separately by different means of transportation through the tunnel and blended in another place. Depending upon the topography which surrounds the mineral deposit, the tunnel of transportation may be horizontal as at 18, or inclined as at 20 or both until it reaches the earth's surface.
After bench 1 has been advanced for a certain distance, the conveyor lO which continuously follows bench l must be moved so that it can be easily reached by a mobile crusher 7 and so tha-t this crusher can be reached by a loading machine ~. Since this ; -conveyor lO is displaced from time to time, it may be called a semi-stationary conveyor. To avoid the need for frequent displace-ments of the semi-stationary conveyor lO, one or several bxidge conveyors 9 (see FIG. lb) may be used. They are placed between the semi-stationary conveyor 10 and mobile crusher 7. Bridge ~i;
conveyors 9 are mounted on wheels or crawlers and therefore can ' be moved easily.
The inclination of the floor 24 where the loading machine 4, mobile crusher 7, and belt conveyor lO stand and move depends upon the distance between the working place of this equipment and the turning point 14 of the bench where one or more shafts 15 and 22 are located (see FIG. ~). It depends also upon the number of benches and their height. The shorter the distance between the working place of the equipment and shaft, the greater the number of benches; the higher the benches, then the steeper is the ~loor. Near the shaft within the turning point area 23, the steepness of the floor may, in certain cases where many high ~ ,:
benches are mined simultaneously with one set of shafts, be so great that it will not be easy to operate and move equipment at this place. For this reason, the whole mining area, as it is - ~ .
~ 8 ~.616~5~
shown in FIG. 4, is divided into two zones - exterior zone 24 and interior zone 23. The exterior zone 24 is mined with a screw-mining method where benches rotate around the shaft and move in a downwardly-sloping screw-shaped path. The interior zone 23 is mined Wi th any other conventional method which permits the floor, where equipment stands and moves, to be kept more or less horizontal.
The area of the interior zone 23 is usually small7 several hundred feet in diameter. The exterior zone 24 is large and may be several miles in diameter. Interior zone 23 and exterior zone 24 may be circular or any other shape.
FIG. 5 shows a perspective view of a screw-mining method combined with conventional equipment. In this case, mineral material must either have special geological characteristics, such that it breaks easily into small pieces during its extraction, ~ ,~
or it must be mined in such a way that it can be loaded on the belt conveyor and transported through the tunnel without damaging the belt, or the mined material must be broken by a crusher 25 installed at the bottom of the shaft before it is loaded on the belt conveyor in the tunnel. In case a crusher is not available, 20 ~ other means of transportation instead of a belt conveyor must be used in the tunnel.
FIG. 6 shows a perspective view o~ a mining method with `~ radial~rotating benches moving in a horizontal plane with a mobile crusher-conveyor system. Two vertical shafts 15 are shown in this Figure. The operation of this method combined with equipment is similar to that described in FIG. 3. However, after the bench has rotated 360 degrees, it ceases to exist and a new bench on a lower level must be developed and all equipment moved to the new bench, which is costly.
The application of the instant invention is simplest when the mineral deposit has the shape of a hill or mountain and _ g _ . ', i ~ s~
can be entirely extracted. All operations in these cases occur in the ore body itself and the removing of overburden through a stripping operation is not requirecl. These cases are illustrated ~` in FIGS. 7a and 8a, showing the cross-sectional view, and in FIGS. 7b and 8b showing a plan view.
`~ In FIGS. 7a and 7b, bench 1 is turning 360 degrees around ` the turning point area 14. Mined mineral material is transported ; through shaft 15 and tunnel 18. Depending on the size of the mountain, its extraction can be accomplished with one or with -~ 10 several independent sets of shafts located in different turning point areas 14.
In order to save the cost of building shafts 15 located in ` turning point area 14 and the tunnel 18, both located within the 1`~
- ~ :~ .:
mineral deposit, the hauling equipment 26, which serves the same -~
purpose, may be placed on the surface of the natural slope of the mountain, which can be adapted to this goal if required (see ! "
FIGS. 8a and 8b).
When a mineral deposit of large three-dimensional extent must be mined, this deposit may be divided into several mining fields, each of them having either one shaft or a group of shafts in a turning point area. Pure economics based on feasibility studies will determine the horizontal and vertical dimension and shape oE each mining field belonging to each shaft or to each set of shafts, or whatever other means are used to transport mined material usually downwardlyO Similarly, the decision must be made concerning the question of how many mining fields are ';
.. , . .
required to extract the whole deposit and what the sequence of operation of these mining field units will be.
i .
As is shown in FIGS. 7a, 7b, 8a and 8b, the shaf-t 15 and tunnel 18 can be saved by placing the hauliny equipment 26 directly on the earth's surface adapted for this purpose. This :'1: ....
! I
is possible to do either close to the outcrop of the mineral deposit or on the border of the mining field in case the adjacent mining field has been previously mi.ned completely.
To save a part of tunnel 18, a short tunnel may be used, as indicated in FIG. 9a which shows a cross-sectional view and FIG.
9b which shows a plan view. The length of belt conveyor 10 on the bench must be adjusted to the changing length of the bench during .
its rotation. After mining field A is mined, a short tunnel 18' in mining field B can be developed to mine this field.
FIG. lOa gives a cross-sectional view and FIG. lOb a plan view of a mineral deposit which dips under a certain angle 30 in the earth's crust. In these Figures, the commercially useful mineral 27 and gangue 29 are mined with the same shaft 15 or set of shafts placed in the turning point area 14. In case only one shaft is available, it must be emptied first before the type of material (useful or gangue) which is mined and transported through this shaft is changed. Useful mineral and gangue is transported through shaft 15, tunnel 18, and inclined drift 20.
To make operation in transportation simpler, it is more .
convenient to have at least two shafts located in turning point .
; ~ area 14, one for useful mineral and another for gangue.
A more simplified operation but more costly arrangement is : :~
presented in FIG. lla which shows a cross-sectional view and FIG.
11b which shows a plan view. ~s can be seen from these Figures, .:
the mining of useful mineral 27 and of gangue 29 utilizes completely ~ :
separate shafts and tunnels. Transportation of useful mineral 27 takes place throu~h shaft or shafts 15, tunnel 18 and inclined : drift 20, and transportation of gangue occurs through shaft or shafts 15', tunnel 18' and inclined drive 20' Material transported through shaEts 15 and 15' can be trans~
ported through one tunnel, eliminating tunnel 18' and inclined drift 20'. The ~ottoms of both shafts must be located on the same level in this case.
-- 11 -- , ,
In another embodiment, the radial-rotating benches move in a horizontal plane.
The screw-mining method comprises one or several benches 'i! which are positioned radially with respect to a turning point area about which they rotate, moving on a downwardly-sloping screw-shaped path. If the turning point is located adjacent the i -,r.
periphery of the mining field, mined mineral material may be ,~
removed from the turning point area by means of one or more conveyors. If the turning point is located at a central point in --~
the mining field, then one or more vertical or inclined shafts ~ ;
are located in the turning point area. Mineral material mined from the benches is hauled to these shafts where it creates a buffer in the haulage system. Mineral material of different quality may be deposited separately in different shafts (or conveyors). These mined materials are either blended during the emptying of these shafts or transported separately to some further destination through one or several horizontal and/or inclined tunnels. These tunnels connect the bottom of the shafts with the earth's surface.
~ .' .
In the case where several high benches are mined simultan-eously with one shaft or with one set of shafts, the slope of the 3~ floor, where equipment must stand and move near the shafts within the turning point area, may become quite steep. It is therefore more convenient to mine mineral material within this small area .: , .: . ~ ~ ' . .:. . - ` ' ~interior zone) not through benches which are moving on down-wardly-sloping screw-shaped paths, but with any method which allows the floor of the turning poi.nt area to be kept more or - less horizontal.
~ oth methods, as such and combined with equipment, are suitable for use in open pit mining for extraction or rock, ore and other mineral materials excavat:ed from the earth's crust.
:,`
During the last two decades, more than fifty plants which ` utilize a "mobile crusher-conveyor system" have been introduced in surface minin~ .in many countries. By crushing the rock or ore . ~ before hauling, this system replaces trucks with belt conveyors, : :
~ thereby permitting a conkinuous, almost fully-automated operation, ,. . .
~ with all of its attendant advantages. Compared with conventional i~ methods and equipment now used in surface mining, the mobile crusher-conveyor system is able to increase drastically man hour output, to reduce the power consumption and maintenance of hauling ~`1 equlpment, and thus to reduce the cost of operation significantly. ~ ~.
.3 Foggy weather or icy roads, which can make trucking extremely hazardous or even impossible, has no effect on belt conveyor haulage. However, plants with mobile crusher-conveyor systems , have been well adapted for open pit mines which operate only one fl bench and mine material of on].y one quality. When several benches are mined simultaneously with conventional methods, the open pit ~;
mines have a circular or elliptical shape. The use of a mobile crusher-conveyor system in such mines requires prohibitive invest-ment for belt conveyors. Furthermore, the mobile crusher-conveyor system does not have the flexibility which truck haulage offers.
Using trucks, material of different quality which must be mined in an open pit can easily be transported from any point in the mine to any different desirable destination. The inventions described -and clained in this specification are able to eliminate these difficulties and to obtain further advanta~es and objectives.
: - 2 -, ~.~.' .
` 1~6~5~1~
It is an object of this invention to make mining operations more efficient, permitting drastic cuts in manpower and in costs.
Another object is to provide an efficient method of mining where several benches can be mined simultaneously.
Another object is to permit the application of a highly i efficient and economic mobile crusher-conveyor system in mines where several benches can be mined simultaneously.
~ Another object is to provide a method of open pit mining ; with a mobile crusher-conveyor system which reduces the length of the belt conveyor. Compared with the circular or elliptical ~.
shape of the open pit now used in surface mining, the length of the belt conveyor is reduced by the methods claimed herein up to six times or even more.
Another object is to permit mining of mineral materials of -~
~ different qualities.
j~ Another object is to permit blending of mined material of different qualities in the mine.
Another object is to provide a buffer in haulage of mined mineral material located between the loading point on the benches and the point of final destination. It will make operation in transportation without costly interruptions and disturbance.
The above-mentioned objects will be evident from the -~
j~ '' ' ':
~ following description of the drawings, in which:
.
FIG. la is a cross-sectional view of a conventional surface mining method with conventional equipment;
; FIG. lb is a cross-sectional view of a conventional surface mlning operation using a mobile crusher-conveyor system;
FIGS. 2a and 2b are cross-sectional and plan views of a conventional open pit mining method with circular or elliptical ~ ;
multi-benches;
FIG. 3 shows a perspective view of the new mining method / oE this invention, called a "screw-mining method", with radial-16~6~5~3 rotating benches moving on a downwardly-sloping screw-shaped path, combined with a mobile crusher-conveyor sys-tem (one or more vertical and/or inclined shafts can be used with this method);
FIG. 4 shows a perspective view of the screw-mining method of this invention combined with the mobile crusher-conveyor system as it is presented in FIG. 3, but with theifollowing difference:
. the large exterior zone of the mining field is mined with radial-rotating benches which move on a downwardly-sloping screw-shaped path; the small interior zone located near the shafts within the turning point area is mined with any other mining method which allows the floor where equipment stands and moves to be kept horizontal; ~:
FIG. 5 is a perspective view of the screw-mining method combined with conventional equipment;
FIG. 6 is a perspective view of a mining method with ~ .
radial-rotating benches which move in a horizontal plane, combined with a mobile crusher-conveyor system;
FIG. 7a and FIG. 7b are cross-sectional and plan views of the methods shown in FIGS. 3, 4 and 5 applied to the mining of a .
hill or mountain with a bench rotation of 360 degrees, using a shaft and tunnel for transportation of mined material; ~:
FIGS. 8a and 8b axe cross-sectional and plan views of the methods shown in FIGS. 3, 4 and 5 with a bench rotation of less than 360 degrees, woxking without shaft and tunnel; the means of material transport are placed on the surface of th~ hill; .: -FIGS. 9a and 9b are cross-sectional and plan views of methods shown in E'IGS. 3, 4 and 5 applied for mining of a large ~ mining area with a short tunnel; after the mining field A is mined ; a new tunnel in the mining field B is built to mine material in this region; ' FIGS. lOa and lOb are cross-sectional and plan views of : _ 4 _ the methods shown in FIGS. 3, ~ and 5 where mining of ore and gangue of the mining field occurs with the same shaft or set of shafts; and : FIGS. lla and llb are cross-sectional and plan views of the methods shown in FIGS. 3, 4 and 5 where mining o~ ore and . gangue of the mining field occurs with a completely separate ` shaft or shafts and the horizontal and/or inclined tunnels associ-ated with them. .
In the drawings to be described more particularly in the following text, FIGS o 3 to 11 show a mining area having circular ::
shape, but it will be understood that an area can have other shapes. .;
The mining art prior to this invention may be seen by re~erring particularly to FIG. la where there is shown a cross- :
sectional view of a surface mining operation with conventional equipment. In hard roc~, bench 1 is blasted with explosives .
which fill borehol~2 drilled in this rockO Blasted material in .
a pile 3 is loaded by a loading machine 4 into a truck 5 which transports this material to a stationary crusher 6. Crushed material is transported to rock storage or to a treatment plant where raw ma~erial is converted into a commercial product. .~
FIG. lb shows a cross-sectional view of a surface mining ~.
operation where a mobile crusher-conveyor system is used. Here ; blasted material from pile 3 is loaded by a loading machine into ,, mobile crusher 7. Crushed material is cleposited by a swinging conveyor ~ which i.s attached to the mobile crusher 7 either onto ~; a bridge conveyor 9 or directly onto a stationary or semi-station-; ary conveyor 10. Conveyor 10 transports crushed material to . .
a rock storage or to a treatment plant.
FIG. 2a shows a cross-sectional view of an open pit mine and FIG. 2b shows the mine in plan. Mineral material mined from benches 1 moves from the middle pOillt 11 or middle axis of the , ~, ~ 5 -:~
6~52~
.
pit to the outside toward the limits of the mining field or ; towards the limits of the mineral deposit. ~he shape of the face of these benches 1 is mostly circular or elliptical, not easily adaptable for the use of helt conveyors which must be straight.
Transportation of mined material from benches 1, which lack direct exit due to the topography of the country, occurs through tunnel 12. To reach this tunnel 12, mined material is transported down from bench to bench which are connected with sloped roads 13. ,~
Even in the case when a group of two or three benches are operated with a single conveyor located on one of these benches and which is connected with other benches b~ means of bridge conveyors 9, such a pit would need many long, very expensive conveyors and bridge conveyors. The required investment for such installation would be prohibitive. Most of the open pit mines are hauling mineral material of different grandes separately from different loading points to several plances or to a point where ~;
mineral material of different grades is blended. This requirement would create serious difficulties for the mobile crusher-conveyor ~ system if applied to conventional mining methods now used in surface mining.
. The invention to which this specification is dixected permits all of the above-mentioned difficulties to be overcome in the best way. Compared to the circular or elliptical shape of bench faces, the total length of conveyors for a screw-mined pit will be six or more times shorter. The operation of such a mine ~;
also permits maximum efficiency in cases when blending of material extracted is required. Following one embodiment of this invention, the movement of a bench or bench faces takes place in the form of a downwardl~-directed "screw" or "spiral" and therefore this method of mining is referred to in this specification and the appended clalms as the "screw-mining method" or "spiral-mining method".
FIG. 3 shows a perspective view o~ a screw-mining method combined .
with a "mobile crusher-conveyor system".
The screw-mining method comprises one or several benches which may be mined simultaneously and are radially positioned ; with respect to a turning point area about which they rotate in a clockwise or counter-clockwise direction 21 moving on a downwardly-sloping screw-shaped path. Each bench 1 rotates many times around the turning point area 14 until it reaches its lowest desirable level which could be the bottom of the planned mining field. The development of a new bench 1 after each rotation of 360 degrees is therefore not required. The costs for development of a new bench and for the moving of all equipment from the old to the new bench are saved. inconveniences associated with the development of a new bench will not occur.
Depending upon the geological, mining and economic conditions one or several vextical or inclined shafts are located in the turning point area. When a mineral deposit dips into the earth's crust under a certain angle as it is shown in FIG. 4, it may be more advantageous to use an inclined shaft 22 instead of a vertical ~ ' one. An inclined shaft may permit the shaft opening, through which mined material is transported, always to be kept close to the center of a mining field. Therefore, one can use the same length length of belt conveyor placed parallel to the bench Eor the entire time.
The conveyor 10 is usually placed parallel to the bench 1 and the mobile crusher 7 is moved between the bench 1 and the conveyor ]0. Mineral material blasted with boreholes 2 is loaded from pile 3 by a :Loading machine 4 into the mobile crusher 7. A
mechanical shovel, front loader, or any other type of loading machine may be used in the system de.scribed. The crusher 7 discharges the broken material onto conveyor 10 which transports it to the turning point area 1~ where one or more vertical shafts lS or inclined shafts 22 or other means of transportation are located. Mineral material oE different ~ualities can be deposited :
4~
in different shafts. At the bottom of these shafts 15 and 22, min~d material is taken out by a feeder 16 and is either blended and transported through tunnels 18 and 20 to a further destination or transported separately by different means of transportation through the tunnel and blended in another place. Depending upon the topography which surrounds the mineral deposit, the tunnel of transportation may be horizontal as at 18, or inclined as at 20 or both until it reaches the earth's surface.
After bench 1 has been advanced for a certain distance, the conveyor lO which continuously follows bench l must be moved so that it can be easily reached by a mobile crusher 7 and so tha-t this crusher can be reached by a loading machine ~. Since this ; -conveyor lO is displaced from time to time, it may be called a semi-stationary conveyor. To avoid the need for frequent displace-ments of the semi-stationary conveyor lO, one or several bxidge conveyors 9 (see FIG. lb) may be used. They are placed between the semi-stationary conveyor 10 and mobile crusher 7. Bridge ~i;
conveyors 9 are mounted on wheels or crawlers and therefore can ' be moved easily.
The inclination of the floor 24 where the loading machine 4, mobile crusher 7, and belt conveyor lO stand and move depends upon the distance between the working place of this equipment and the turning point 14 of the bench where one or more shafts 15 and 22 are located (see FIG. ~). It depends also upon the number of benches and their height. The shorter the distance between the working place of the equipment and shaft, the greater the number of benches; the higher the benches, then the steeper is the ~loor. Near the shaft within the turning point area 23, the steepness of the floor may, in certain cases where many high ~ ,:
benches are mined simultaneously with one set of shafts, be so great that it will not be easy to operate and move equipment at this place. For this reason, the whole mining area, as it is - ~ .
~ 8 ~.616~5~
shown in FIG. 4, is divided into two zones - exterior zone 24 and interior zone 23. The exterior zone 24 is mined with a screw-mining method where benches rotate around the shaft and move in a downwardly-sloping screw-shaped path. The interior zone 23 is mined Wi th any other conventional method which permits the floor, where equipment stands and moves, to be kept more or less horizontal.
The area of the interior zone 23 is usually small7 several hundred feet in diameter. The exterior zone 24 is large and may be several miles in diameter. Interior zone 23 and exterior zone 24 may be circular or any other shape.
FIG. 5 shows a perspective view of a screw-mining method combined with conventional equipment. In this case, mineral material must either have special geological characteristics, such that it breaks easily into small pieces during its extraction, ~ ,~
or it must be mined in such a way that it can be loaded on the belt conveyor and transported through the tunnel without damaging the belt, or the mined material must be broken by a crusher 25 installed at the bottom of the shaft before it is loaded on the belt conveyor in the tunnel. In case a crusher is not available, 20 ~ other means of transportation instead of a belt conveyor must be used in the tunnel.
FIG. 6 shows a perspective view o~ a mining method with `~ radial~rotating benches moving in a horizontal plane with a mobile crusher-conveyor system. Two vertical shafts 15 are shown in this Figure. The operation of this method combined with equipment is similar to that described in FIG. 3. However, after the bench has rotated 360 degrees, it ceases to exist and a new bench on a lower level must be developed and all equipment moved to the new bench, which is costly.
The application of the instant invention is simplest when the mineral deposit has the shape of a hill or mountain and _ g _ . ', i ~ s~
can be entirely extracted. All operations in these cases occur in the ore body itself and the removing of overburden through a stripping operation is not requirecl. These cases are illustrated ~` in FIGS. 7a and 8a, showing the cross-sectional view, and in FIGS. 7b and 8b showing a plan view.
`~ In FIGS. 7a and 7b, bench 1 is turning 360 degrees around ` the turning point area 14. Mined mineral material is transported ; through shaft 15 and tunnel 18. Depending on the size of the mountain, its extraction can be accomplished with one or with -~ 10 several independent sets of shafts located in different turning point areas 14.
In order to save the cost of building shafts 15 located in ` turning point area 14 and the tunnel 18, both located within the 1`~
- ~ :~ .:
mineral deposit, the hauling equipment 26, which serves the same -~
purpose, may be placed on the surface of the natural slope of the mountain, which can be adapted to this goal if required (see ! "
FIGS. 8a and 8b).
When a mineral deposit of large three-dimensional extent must be mined, this deposit may be divided into several mining fields, each of them having either one shaft or a group of shafts in a turning point area. Pure economics based on feasibility studies will determine the horizontal and vertical dimension and shape oE each mining field belonging to each shaft or to each set of shafts, or whatever other means are used to transport mined material usually downwardlyO Similarly, the decision must be made concerning the question of how many mining fields are ';
.. , . .
required to extract the whole deposit and what the sequence of operation of these mining field units will be.
i .
As is shown in FIGS. 7a, 7b, 8a and 8b, the shaf-t 15 and tunnel 18 can be saved by placing the hauliny equipment 26 directly on the earth's surface adapted for this purpose. This :'1: ....
! I
is possible to do either close to the outcrop of the mineral deposit or on the border of the mining field in case the adjacent mining field has been previously mi.ned completely.
To save a part of tunnel 18, a short tunnel may be used, as indicated in FIG. 9a which shows a cross-sectional view and FIG.
9b which shows a plan view. The length of belt conveyor 10 on the bench must be adjusted to the changing length of the bench during .
its rotation. After mining field A is mined, a short tunnel 18' in mining field B can be developed to mine this field.
FIG. lOa gives a cross-sectional view and FIG. lOb a plan view of a mineral deposit which dips under a certain angle 30 in the earth's crust. In these Figures, the commercially useful mineral 27 and gangue 29 are mined with the same shaft 15 or set of shafts placed in the turning point area 14. In case only one shaft is available, it must be emptied first before the type of material (useful or gangue) which is mined and transported through this shaft is changed. Useful mineral and gangue is transported through shaft 15, tunnel 18, and inclined drift 20.
To make operation in transportation simpler, it is more .
convenient to have at least two shafts located in turning point .
; ~ area 14, one for useful mineral and another for gangue.
A more simplified operation but more costly arrangement is : :~
presented in FIG. lla which shows a cross-sectional view and FIG.
11b which shows a plan view. ~s can be seen from these Figures, .:
the mining of useful mineral 27 and of gangue 29 utilizes completely ~ :
separate shafts and tunnels. Transportation of useful mineral 27 takes place throu~h shaft or shafts 15, tunnel 18 and inclined : drift 20, and transportation of gangue occurs through shaft or shafts 15', tunnel 18' and inclined drive 20' Material transported through shaEts 15 and 15' can be trans~
ported through one tunnel, eliminating tunnel 18' and inclined drift 20'. The ~ottoms of both shafts must be located on the same level in this case.
-- 11 -- , ,
Claims (21)
1. An open pit mine for the extraction of mineral materials from the earth's crust comprising:
- a turning point pit floor area having a substantially horizontally level floor adapted to facilitate the operation of material-handling equipment and to receive crushed mined mineral material, - at least one bench moving on a downwardly sloping helical path extending radially outwardly from the turning point pit floor area, - a mobile crusher for crushing mined mineral materials located adjacent the bench, - a belt conveyor system for conveying crushed mined mineral materials from the crusher to the turning point pit floor area, and - shaft means communicating with said pit floor area for discharging the crushed mined mineral materials downwardly from the turning point pit floor area.
- a turning point pit floor area having a substantially horizontally level floor adapted to facilitate the operation of material-handling equipment and to receive crushed mined mineral material, - at least one bench moving on a downwardly sloping helical path extending radially outwardly from the turning point pit floor area, - a mobile crusher for crushing mined mineral materials located adjacent the bench, - a belt conveyor system for conveying crushed mined mineral materials from the crusher to the turning point pit floor area, and - shaft means communicating with said pit floor area for discharging the crushed mined mineral materials downwardly from the turning point pit floor area.
2. A mine according to Claim 1 in which the turning point pit floor area is located adjacent the periphery of the area to be mined.
3. A mine according to Claim 2 in which a belt conveyor is provided to transport the mined mineral materials from the turning point pit floor area to a further destination.
4. A mine according to Claim 2 in which the mined mineral materials are transported from the turning point pit floor area by a plurality of conveyors to permit mined mineral materials of different qualities to be separately conveyed to a blending station.
5. A mine according to Claim 1 in which the turning point pit floor area is centrally located in the area to be mined.
6. A mine according to Claim 5 in which the means for discharging the crushed mineral materials from the turning point pit floor area is at least one generally downwardly-directed vertical or inclined shaft communicating with the pit floor area.
7. A mine according to Claim 5 in which the means for discharging the crushed mineral materials from the turning point pit floor area are a plurality of downwardly-directed shafts communicating with the pit floor area for receiving mined mineral materials of different qualities.
8. A mine according to Claim 7 in which blending means are established adjacent the discharge end of the downwardly-directed shafts.
9. A mine according to Claim 1 in which the bench moves on a downwardly-sloping helical path.
10. A mine according to Claim 1 wherein the bench moves on a generally horizontally-extending surface.
11. A method of open-pit mining for the extraction of mined material from the earth's crust comprising:
- establishing a turning point pit floor area having a shaft, - developing at least one bench radially outwardly from the turning point pit floor area, - mining the bench;
- loading mined mineral materials into a mobile crusher and crushing the mined mineral materials adjacent the bench;
- transporting the crushed mined mineral materials to the turning point pit floor area by a conveyor belt system; and - discharging the mined mineral materials in a generally downwardly-extending direction by means of said shaft.
- establishing a turning point pit floor area having a shaft, - developing at least one bench radially outwardly from the turning point pit floor area, - mining the bench;
- loading mined mineral materials into a mobile crusher and crushing the mined mineral materials adjacent the bench;
- transporting the crushed mined mineral materials to the turning point pit floor area by a conveyor belt system; and - discharging the mined mineral materials in a generally downwardly-extending direction by means of said shaft.
12. A method according to Claim 11 in which the turning point pit floor area is established at the periphery of the area to be mined.
13. A method according to Claim 12 in which mined mineral materials of different qualities are transported in sequence "one by one: by a single belt conveyor to a blending station.
14. A method according to Claim 11 in which the turning point pit floor area is established at a central point of the area to be mined.
15. A method according to Claim 14 in which the crushed mined mineral material is discharged through at least one downwardly-directed shaft located at the turning point pit floor area.
16. A method according to Claim 14 in which mined mineral materials of different qualities are transported in sequence "one by one" through one shaft and then by one belt conveyor through a tunnel or inclined drift to a blending station.
17. A method according to Claim 14 in which the crushed mined mineral material is discharged from the turning point pit floor area through a plurality of downwardly-directed shafts adapted to receive mined mineral materials of different qualities.
18. A method according to Claim 17 in which the mined mineral materials of different qualities taken from the plurality of shafts are conveyed on separate belt conveyors through a tunnel or inclined drift to a blending station.
19. A method according to Claim 14 in which the bench rotates about a point located within the turning point pit floor area and moves in a downwardly-slopoing helical path.
20. A method according to Claim 14 in which the bench rotates about a point located within the turning point pit floor area and moves in a generally horizontal plane.
21. A method according to Claim 17 in which the discharged mined mineral materials are blended underneath the shafts before further transportation.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA257,637A CA1064528A (en) | 1976-07-23 | 1976-07-23 | Open pit mine |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA257,637A CA1064528A (en) | 1976-07-23 | 1976-07-23 | Open pit mine |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1064528A true CA1064528A (en) | 1979-10-16 |
Family
ID=4106488
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA257,637A Expired CA1064528A (en) | 1976-07-23 | 1976-07-23 | Open pit mine |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA1064528A (en) |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103133003A (en) * | 2013-02-25 | 2013-06-05 | 中国矿业大学 | Opencast mine end slope near-slope mining method |
| CN103216238A (en) * | 2012-12-28 | 2013-07-24 | 中国神华能源股份有限公司 | Open pit coal mine mining process |
| CN114251099A (en) * | 2021-11-25 | 2022-03-29 | 中交二公局东萌工程有限公司 | Blasting excavation method for crossed caverns |
-
1976
- 1976-07-23 CA CA257,637A patent/CA1064528A/en not_active Expired
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN103216238A (en) * | 2012-12-28 | 2013-07-24 | 中国神华能源股份有限公司 | Open pit coal mine mining process |
| CN103133003A (en) * | 2013-02-25 | 2013-06-05 | 中国矿业大学 | Opencast mine end slope near-slope mining method |
| CN114251099A (en) * | 2021-11-25 | 2022-03-29 | 中交二公局东萌工程有限公司 | Blasting excavation method for crossed caverns |
| CN114251099B (en) * | 2021-11-25 | 2024-04-16 | 中交二公局东萌工程有限公司 | Blasting excavation method for cross grotto |
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