Method and apparatus for hydraulic transportation of mined coal

Abstract

A method and apparatus for hydraulic transportation of mined coal from a plurality of mining sites in an underground mine to a station at the surface of the mine is disclosed wherein mined coal is combined with a carrier liquid, cleaned by removal of waste coal tailing therefrom, combined with similarly cleaned coal at a junction box centrally located within the mine, pumped to the surface station, and separated from the carrier liquid. Waste coal tailings are hydraulically transported to a sump where they are separated from the carrier liquid. Carrier liquid used to carry waste coal is returned to the station where it is combined with carrier liquid from the clean coal operation and the aggregate liquid is recycled to the mining sites for further use in hydraulic transport.

Description

BACKGROUND OF THE INVENTION

This invention relates generally to a method and apparatus for transportation of mined coal from continuous mobile mining machines to a surface station outside the mine, and particularly to hydraulic transportation by use of a carrier liquid and recycling of the carrier liquid to the mining site.

In any mining operation wherein continuous mobile mining machines are used a prime requisite must be the quick and efficient removal of coal as it is mined keeping pace with the machine so as not to impede the operation.

Conventional methods for transportation include loading newly mined coal onto shuttle cars which transport the coal a short distance from the mining site to conveyors. These conveyors are linked to centrally located rail haulage systems which in turn provide transport to the surface. Since only coal particles of at least a given size are economically useable the waste tailings must be separated from the coal at the surface to provide "clean coal" for transport to the distributor.

Methods have been proposed which include elimination of the shuttle car haulage system by utilizing endless conveyors suitably linked so as to provide continuous transport from the mining machines to the central rail haulage system and it has also been proposed to eliminate the rail haulage system altogether by means of conveyors from the mining machine to the surface.

Since all of these methods involve relatively complex interrelated systems, it will be readily apparent that a breakdown or stoppage at one point in the system will result in costly delays to the producer.

In order to overcome these disadvantages, it has been proposed in U.S. Pat. No 3,260,548, for example, to employ a hydraulic method of transport wherein coal is transported from the mining machine to a mobile slurry preparation terminal where it is comminuted and mixed with a carrier liquid to form a slurry. The slurry is then transported along flexible conduits to a central underground relay station where it is further comminuted and then transported along conduits to the surface. Carrier liquid is separated from the coal and returned to the mining operation.

While the method employed in the aforesaid patent has eliminated some of the enumerated problems, the separating of useable coal from waste is achieved at the surface at a separate processing station distantly located from the mine before it can be distributed to consumers.

SUMMARY OF THE INVENTION

The present transportation system contemplates a novel method and apparatus for hydraulic transportation of clean coal from a plurality of mining sites to a surface station of an underground mine, wherein coal dislodged by a plurality of mine faces by continuous mobile mining machines is transported by means of bifurcated conveyors to mobile slurring devices. Coal is crushed as it enters the slurrying devices and falls into bins where it is mixed with a carrier liquid to form a slurry. Slurries thus formed are transported along flexible conduits to a series of cleaning tables where waste coal slurries and clean coal slurries are formed by separation of waste coal particles, or tailings along with a part of the water from the slurry. Clean coal slurries are transported along clean coal conduits to a junction box wherein they are combined to form an aggregate slurry. The waste coal slurries are transported to a sump wherein waste coal tailings are separated. The aggregate clean coal slurry is transported along a conduit to a station at the surface of the mine where the slurry is separated into its clean coal and carrier liquid components. Remaining liquid from the waste coal slurry is pumped from the slurry upwardly along a conduit to a series of stepped settling ponds wherein any coal particles remaining in suspension in the waste coal carrier liquid are allowed to settle out of the liquid. Remaining liquid is fed by force of gravity to a stream feeding the station at the surface. At this station, carrier liquids remaining from the clean coal and waste coal slurries are combined and returned along a conduit to the junction box where they are redistributed along conduits to the mining sites for further use in the transportation system.

It is object of this invention to provide a novel method and apparatus for hydraulic transportation of coal wherein waste coal is separated from clean coal at a point near the mining site within an underground mine, and clean coal only is transported to the surface.

Another object of this invention is to provide a novel method and apparatus for hydraulic transportation of waste coal away from the mining area to a centralized location within the mine for waste distribution.

Yet another object of this invention is to provide a novel method and apparatus for hydraulic transportation of mined coal wherein the carrier liquids used for transport of both clean coal and waste coal are separated from the coal, combined, and recycled to be used again in the mining operation.

Still another object of this invention is to provide a novel method for separation of waste coal particles from the carrier liquid.

Various means for practicing the invention and other advantages and novel features thereof will be apparent from the following detailed description of an illustrative preferred embodiment of the invention, reference being made to the accompanying drawings.

DESCRIPTION OF THE DRAWINGS

In the drawings:

FIG. 1 is a block diagram illustrating the coal transportation and carrier liquid recycling systems of the invention within and at the surface of a coal mine.

FIG. 2 is a perspective view illustrating the continuous miner and slurrying device of the instant invention.

FIG. 3 is a plane view partly in section illustrating the internal transportation system in an underground mine.

Referring to FIG. 1, there is shown a block diagram of a section of a coal mine and surface thereof, in which coal dislodged from a plurality of mine faces by continuous mobile mining machines 1 is transported by means of bifurcated conveyors 2 to mobile slurrying devices 3. At slurrying device 3 coal is comminuted by means of crushers mounted thereon and the coal mixed with a carrier liquid, such as, for example, water to form a slurry. Slurries thus formed are pumped along flexible conduits 4 to cleaning tables 5 wherein waste coal tailings are separated from the slurries by any conventional means, for example, horizontally disposed screens within tables 5 having apertures of a diameter such that coal particles of a size deemed unsuitable for further processing fall through the screens and are mixed with a part of the water from the slurries entering cleaning tables 5 from conduits 4 to form waste coal slurries. Waste coal slurries thus formed exit cleaning tables 5 along conduits 6 to a common sump 7 wherein waste coal tailings are separated from the water. Clean coal slurries are formed by removal of waste coal tailings in cleaning tables 5 and exit tables 5 along conduits 8 to a junction box 9 centrally located within the mine so as to provide a common source for transport of clean coal to a surface processing station 1. Conduit 10 is provided for removal of clean coal, remaining in slurry form, from junction box 9 to surface processing station 1 by means of conventional pumps situated at junction box 9. The slurry is separated at station 11 into clean coal and water by conventional means will known in the art. The remaining water, augmented by water from an additional source, such as a stream 12 fed by recycled water from the waste coal slurry as hereinafter described, is returned to junction box 9 via conduit 13 where it is redistributed along conduits 14 and 15 to continuous miners 1 and slurrying devices 3 for further transportation of coal.

Water remaining from separation of waste coal tailings from the waste coal slurry at sump 7 is pumped by suitable pumping means, located within sump 7, upwardly along conduit 16 to a plurality settling ponds 17, 19, 21 located above the mine. Settling ponds 17, 19, 21 are located in stepped relationship to each other and interconnected by means of piping 18, 20 such that water from pond 17 is fed by force of gravity to pond 19 and water from pond 19 is similarly fed to pond 21. Settling ponds 17, 19 21 serve further to separate any coal particles not separated at sump 7 such that water flowing by force of gravity from an outlet 22 of settling pond 21 to stream 12 enters stream 12 in a relatively purified condition for recycling to the mining operation. Settling ponds 17, 19, 21 are provided due to the greater degree of difficulty in removing waste coal tailings of small particle size from the waste coal slurry than that encountered in separation of crushed coal from the clean coal slurry.

Referring now to FIG. 2, a slurrying device generally designated 3 is attached to a continuous mining machine well known in the art and generally designated at 1 by means of a bifurcated chute conveyor 2 having a forward portion 21 which includes a belt-type conveyor also well known in the art. Forward portion 21 of chute conveyor 2 projects rearwardly of continuous miner 1 and comprises an extension of frame 23 of continuous miner 1. Extending longitudinally rearward from forward portion 2 of chute conveyor 2 are female flanged extensions 24 curved so as to mate with male flanged extensions 25 extending longitudinally forward of rearward portion 22 of chute conveyor 2. Flanged extensions 24 and 25 are mated so as to provide connection between forward portion 21 and rearward portion 22, thus forming a continuous path along chute conveyor 2 between continuous miner 1 and slurrying device 3. Rearward portion 22 overlaps forward wall 26 of slurrying device 3 and is held in mating engagement with wall 26 by means of a flange 27 curved downwardly from the underside 28 of rearward portion 22. Thus forward motion is imparted to slurrying device 3 from the forward motion of continuous miner 1 through conveyor 2.

Slurrying device 3 comprises an open box-like structure generally designated at 29 having a front wall 26, two side walls 30, a rear wall 31, and a bottom (not Shown). Continuous belt tracks 32 of a type well known in the art are moveably mounted by conventional means to side walls 30.

A crusher, generally designated at 33 is fixedly mounted to side walls 30 without box-like structure 29. Crusher 33 comprises a crusher drum 34 covered over its surface by pointed projections 35 and the drum is rotatably mounted along an axis perpendicular to the axis of side walls 30 of structure 29, by means of a shaft (not shown) driven by a motor 36. Surrounding crusher drum 34 is a crusher box 37 fixedly mounted to side walls 30 by means of supports 38.

Jets of water 39 are supplied to crusher wheel 34 through apertures 40 longitudinally spaced along a pipe 41 horizontally mounted several inches above wheel 34. Pipe 41 is a continuous length of pipe curved at both ends so as to form two vertical sections 42 and a horizontal section 43 which is perforated at regular intervals to form apertures 40. Vertical sections 42 of pipe 41 are fixedly mounted to side walls 30.

A supply of water is fed to pipe 41 by means of a flexible branch conduit 44 joining a flexible supply conduit 45 at a valve connector 46. Supply conduit 45 also supplies water to the rearward portion 23 of continuous miner 1, Supply conduit 45 is supported along the wall of the underground mine by means of support hooks 47.

Projecting rearwardly of slurrying device 3 is a flexible discharge conduit 48 centrally mounted to the rear walls 31 of structure 29. A valve 49 is provided at the junction of discharge conduit 48 and rear wall 31, to regulate the flow of coal water slurry 50 formed in structure 29.

Slurry 50 is formed in the following manner. Coal 51 dislodged from a mine face 52 by continuous miner 1 is fed through hinged doorway 53 to the forward portion 21 of chute conveyor 2. The movement of coal 50 along its path in conveyor 2 is facilitated by means of water fed through supply conduit 46. As the coal 50 is discharged from rearward portion 22 of conveyor 2, it drops onto revolving crusher wheel 34 and is crushed between projections 35 and the walls of crusher box 37. As the above described crushing action takes place, jets of water 39 carry the coal off the crusher wheel 34, maintaining projections 35 free of caked coal. The coal water mixture, or slurry 50 thus formed, flows from the crusher area and into the rearward portion of slurrying device 3. From slurrying device 3, the slurry 50 is discharged through discharge conduit 48. This can be accomplished by means of pump 54 though a gravity fed method would be within the scope of the invention.

Referring now to FIG. 3, coal removal from a plurality of mining stations is shown wherein coal at mine faces 52 is dislodged by continuous miners 1, transported by means of chute conveyors 2 to slurrying devices 3 and slurried as described above. The slurry 50 thus formed is pumped from slurrying device 3 through discharge conduit 48 to cleaning tables, generally designated 5 wherein slurry 50 is separated into a clean coal slurry and a waste coal slurry. Cleaning tables 5 are comprised of a plurality of end connected units 55, 56, 57, 58 placed longitudinally in the direction of the flow of slurry 50. Units 55, 56, 57, 58 are similar in construction and operation with the exception that they are constructed in stepped relationship to one another such that the forwardly progressing slurry is caused to overflow from one unit into the next. Separation of slurry 50 into clean coal and water coal slurries can be accomplished by means well known in the art. One method for separation would be the use of screens horizontally disposed within each stepped unit, each screen having holes of sufficient diameter to allow passage of coal tailings of a size considered to be waste in the operation. In operation slurry 50 passes from conduit 48 into unit 55 of cleaning tables 5 where a part of the waste tailings and water contained within slurry 50 are separated resulting in the formation of a separately advancing waste coal slurry beneath an advancing clean coal slurry. Each slurry then passes through successive stepped units 56, 57, 58 with further separation of waste coal tailings in each unit.

Clean coal slurries pass from units 58 of cleaning tables 5 into clean coal conduits 59, extending from units 58 to a junction box, generally designated 9, centrally located so as to receive clean coal slurries from a plurality of separate mining operations. Junction box 9 comprises an inner box 61 nested within an outer box 62, An aggregate slurry 63 is formed within inner box 61 from the discharge of clean coal slurries from conduits 59, so as to provide a single source from which transportation of clean coal to the surface of the underground mine can easily be effected. Thus, aggregate slurry 63 is pumped through port 64 of inner box 61 by means of a discharge pump 65 into a conduit 66 which connects inner box 61 with a coal removal station (not shown) where clean coal is separated from its carrier water and the water is returned for reuse in the mining operation along a return conduit 67. Recycled water from return conduit 67 empties into outer box 62 of junction box 9 for redistribution. A plurality of return pumps 68 effect redistribution of clean water along supply conduits 45 to continuous miners 1 and slurrying devices 3.

Waste coal slurries exit units 58 of cleaning tables 5 into a plurality of waste coal conduits 60 for transfer to a sump, generally designated 69, where waste coal tailings are separated from carrier water. Waste coal conduits 60 merge at a point 71 with a single discharge conduit 72 for transfer to sump 69. Sump 69 comprises a generally circular pit 74 narrowing to form an elongated entrance passageway 75. A plurality of filter screens 77, 78, 79, 80 are vertically disposed along passageway 75 to provide means for separation of waste coal tailings from waste coal slurry 76 as it exits discharge opening 73 of conduit 72. Screens 77, 78, 79, 80 can be provided with openings of decreasing diameter with screen 77 of conduit 72 having apertures of a diameter large enough to pass most of the tailings in waste coal slurry 76, and screen 80 disposed nearest the opening into pit 69, having apertures small enough to block most of tailings, thus providing an even distribution of tailings within passageway 75, and water 81 substantially free of tailings in pit 74.

A pump 82 is provided at the bottom of circular pit 74 of sump 69, for recirculation of water 81 separated from waste coal slurry 76. Connected to pump 82 is a conduit 83 for transfer of water 81 to settling ponds (not shown) located outside the underground mine.

Thus it can be seen that there is provided according to the present invention a method and apparatus for continuous mining wherein the coal is crushed, screened and sorted within the mine, the clean coal being transported by a slurry within the mine to the surface. The tailings are separated from the carrier liquid within the mine and the carrier liquid is filtered and recirculated.

Obviously many modifications and variations of the present invention are possible in light of the above teachings.

Claims

What is claimed as new and is desired to be secured by Letters Patent is:

1. A method for transporting mined coal from a plurality of working faces of an underground mine to a station at the surface of said mine comprising the steps of:

dislodging said coal from said working faces by means of a mobile underground mining machine;

combining said coal with carrier liquid adjacent said working faces;

conveying said mined coal and carrier liquid by means of bifurcated conveyors to crushers fixedly mounted to modile slurrying devices;

crushing said mined coal;

admixing said crushed coal with additional carrier liquid to form slurries within said slurrying devices;

transporting said slurries to said cleaning tables;

forming clean coal slurries and waste coal slurries within said cleaning tables by removing waste coal and a part of said carrier liquid from said slurries by screening means horizontally disposed within said cleaning tables, such that clean coal and a part of said carrier liquid remain above said screens and waste coal and a part of said carrier liquid fall below said screens;

pumping said clean coal slurries along conduits from said cleaning tables to a junction box centrally located within said underground mine;

admixing said clean coal slurries within said junction box to form an aggregate slurry;

pumping said aggregate slurry along a conduit from said junction box to said station at the surface of said underground mine by means of a pump located adjacent said junction box;

separating said slurry into clean coal and carrier liquid;

pumping said waste coal slurries along conduits away from said cleaning tables and joining said conduits with a single conduit leading to the entrance passageway of a sump so as to an aggregate waste coal slurry;

pumping said aggregate waste coal slurry from said single conduit into said entrance passageway to said sump;

separating waste coal tailings from said waste coal slurry by screening means disposed vertically within said entrance passageway;

pumping remaining liquid from said waste coal slurry upwardly along a conduit to a first settling pond located above said underground mine;

transporting said remaining liquid from said first settling pond by force of gravity to a second settling pond disposed in stepped relationship adjacent to and below said first settling pond;

transporting said remaining liquid from said second settling pond by force of gravity to a third settling pond disposed in stepped relationship adjacent to and below said second settling pond;

transporting said remaining liquid from said third settling pond by force of gravity to said station at the surface of said underground mine;

combining said remaining liquid with said remaining liquid from said clean coal slurry and pumping said combined liquid along a conduit to said junction box; and

pumping said combined liquid by pump means located adjacent said junction box along a plurality of conduits to said underground mines and said slurrying devices.

2. Apparatus for transporting mined coal from a working face of an underground mine to a station at the surface of said mine comprising:

a continuous mobile mining machine operable to dislodge coal from said working face;

conveyor means operably connected to said mining machine to transport a mined coal rearwardly of said mining machine;

a continuous mobile slurrying device operably connected to said conveyor means;

a crusher fixedly mounted to said slurrying device operable to crush mined coal as it is fed into said slurrying device;

a first flexible conduit for supplying carrier liquid to said slurrying device for formation of a slurry of crushed coal and said liquid therein;

a second flexible conduit for transporting said slurry rearwardly of said slurrying device;

a plurality of cleaning table means to separate waste coal tailings from said slurry to form a clean coal slurry and a waste coal slurry, said cleaning table means comprising a plurality of series connected cleaning tables, the first of said cleaning table in fluid communication with said second flexible conduit and for dividing said slurry into a clean coal slurry and a waste coal slurry, and each succeeding cleaning table receiving the clean coal slurry formed by the preceeding cleaning table for dividing the received clean coal slurry into a further clean coal slurry and a further waste coal slurry which is combined with the waste coal slurry from the preceeding cleaning table;

conduit means operable to transport said clean coal slurry rearwardly from said cleaning tables;

a junction box centrally located within said underground mine comprising means for receiving said clean coal slurry and means for receiving a supply of carrier liquid substantially free of coal;

conduit means operable to transport said clean coal slurry from said junction box to said station at the surface of said underground mine;

means operable to separate said clean coal slurry into clean coal and remaining carrier liquid;

conduit means for transporting said waste coal slurry away from the last of said cleaning table means;

a sump operable to receive said waste coal slurry;

means within said sump to separate waste coal tailings from said waste coal slurry;

conduit means for transporting remaining liquid from said waste coal slurry above said underground mine;

a plurality of settling ponds located above said underground mine operable to receive said remaining liquid from said waste coal slurry;

means for transporting said remaining liquid from said settling ponds to said station at the surface of said underground mine;

means for combining said remaining liquid with said remaining liquid from said clean coal slurry;

conduit means for returning said combined liquid from said station at the surface of said underground mine to said junction box;

conduit means for returning said combined liquid from said junction box to said continuous mobile mining machine and said slurrying device.

3. The apparatus as set forth in claim 2 wherein said slurrying device comprises:

an open box like structure having a front wall, two side walls, a rear wall and a bottom constructed so as to be water tight;

a crusher fixedly mounted to said side walls above said box-like structure having a crusher drum rotably mounted by means of a shaft driven by a motor said crusher drum covered over its surface by pointed projections, a crusher box fixedly mounted to said side walls and surrounding said crusher drum, and a length of pipe horizontally mounted above said drum having apertures operable to supply liquid to the surface of said drum;

first pump means operable to pump a carrier liquid from said return conduit means to said box-like structure and apertured pipe;

second pipe means rearwardly adjacent to said box-like structure operable to pump a slurry formed within said structure away from said structure; and

continuous belt tracks moveably mounted to said box-like structure and operable to supply motion to said structure.

4. The apparatus as set forth in claim 2, wherein said cleaning tables comprise a plurality of end connected units, disposed longitudinally in the direction of flow of said slurry, and constructed in stepped relationship to one another such that each succeeding unit is of lesser height than the unit preceeding it.

5. The apparatus as set forth in claim 4, wherein said separation means comprises a plurality of horizontally disposed screens within said cleaning tables.

6. The apparatus as set forth in claim 2, wherein said junction box comprises an inner box nested within an outer box, said inner box operable to receive said clean coal slurry and said outer box operable to receive said carrier liquid substantially free of coal.

7. The apparatus as set forth in claim 2, wherein said sump comprises:

a generally circular pit narrowing at its entrance to form an elongated passageway;

a plurality of filter screens vertically disposed along said passageway operable to separate waste coal tailings from said waste coal slurry, leaving a remaining carrier liquid; and

a pump located within said pit and operable to remove said remaining carrier liquid from said pit.

8. A method for transporting mined coal from a working face of an underground mine to a station at the surface of said mine comprising the steps of:

dislodging said coal from said working face by means of a mobile underground mining machine;

conveying said coal from said mining machine to a mobile slurrying device;

crushing said coal;

admixing said crushed coal with carrier liquid to form a slurry;

transporting said slurry from said slurrying device to a plurality of cleaning tables;

forming a clean coal slurry and a waste coal slurry by removing waste coal and a part of said carrier liquid from said slurry;

transporting said clean coal slurry to a junction box centrally located within said underground mine;

transporting said clean coal slurry to a station at the surface of said underground mine;

separating clean coal from said clean coal slurry;

transporting said waste coal slurry from said cleaning tables to a sump;

separating waste coal tailings from said water coal slurry;

transporting remaining liquid from said waste coal slurry to a plurality of settling ponds located above said underground mine;

transporting said remaining liquid from said settling ponds to said station at the surface of said underground mine;

combining said remaining liquid with said remaining liquid from said clean coal slurry and returning said combined liquid to said junction box;

returning said combined liquid from said junction box to said slurrying device;

transporting said waste coal slurry from said cleaning tables by pumping said slurry along a conduit to an entrance passageway of a sump;

separating waste coal tailings from said waste coal slurry by vertically disposed screening means located in said entrance passageway of said sump;

transporting remaining liquid from said waste coal slurry by pumping said liquid upwardly along a conduit to a first settling pond to a second settling pond;

transporting said remaining liquid from said second settling pond to a third settling pond; and

transporting said remaining liquid from said third settling pond to said station at the surface of said underground mine.