Title of Invention

"SHORTWALL MINING EQUIPMENT USEFUL FOR EXTRACTION OF PILLARS IN UNDERGROUND COAL MINES."

Abstract

Shortwall mining equipment useful for extraction of pillars in underground coal mines which comprises a series of self advancing powered supports (1) for placement along pillars (2) under extraction, the said pillars under extraction being located within a panel (3) which is rounded by barrier pillars (4), an armoured face conveyor (5) being fixed to the said barrier pillars, characterised in that the said series of supports (1) has a goaf end a support mechansim (6) on a base frame (14) with a side shield (7) including a plate (8) and hanging steel guard (9), a hydraulic ram side arms (10), a front side hook (11) and back side hook (12), the side shield (7) being hung from canopy (13) on the top of the said support mechanism (6), at least two of the hanging steel guards (9) being freely hung from an inner side of the side shield (7), the hydraulic ram side arms (10) being horizontally fixed within the support mechanism (6) to support the side shield (7), the base frame (14) being provided with the front and back side of hooks (11 & 12) to facilitate pulling of the support mechanism (6), the said armoured face conveyor (5) being provided with a shearer (15) having a cutter drum (16) coupled with a centrally located ranging arm (17), the outbye end of the said armoured face conveyor (5) at a right angle to set upon a light duty chain conveyor (18) as a freely advancing bridge, the said light duty chain conveyor (18) is connected to a belt conveyor (19) at the said outbye of the said panel (3).

Full Text

This invention relates to shortwall mining equipment useful for extraction of pillars in underground coal mines. In coal mines, generally coal seams are initially developed into pillars and cross galleries (roadways). These pillars are subsequently extracted which is called depillaring. In general, bord and pillar depillaring is done in conventional methods with conventional equipment. Sometimes, intermediate technologies with side discharge loaders (SDLs) and load haul dumpers (LHDs) are being used for extraction. There is another system of exploiting coal seams in long pillars with the help of self advancing powered roof supports, continuous cutters, loaders and conveyors from the face to the outbye. The long blocks are developed in a different way, this is called longwall mining. The total system of longwall mining, its uses and an improved longwall equipment for further mechanisation as has been claimed in an earlier patent application No.288/DEL/93 may be referred in this connection. There is no such continuous cutting, loading and conveying system with an appropriate layout of self advancing powered roof supports for pillar extraction in shortwall mining. As such, a longwall equipment package cannot be used in a short form for existing pillar extraction. Therefore, it necessitates a shortwall equipment package with an appropriate layout for extraction of pillars in a bord and pillar panel. The drawbacks of the available devices are that there is no appropriate powered roof support at the end of the face towards goaf side. The powered support as generally available is having rear shield and top canopy as shown in figure 3 of the drawings accompanying this specification, but it does not have any side protecting shield to resist the loose rook load from goaf side. Secondly, there is no appropriate layout for extraction of developed coal pillars with the shortwall face equipment alonnwith its feasible cutting, loading, transporting and supporting system. There is no scientific combination of equipment with innovative layout for extraction of short block of coals in underground mines. The object of the present invention is to provide an improved equipment for shortwall mining useful for extraction of pillars in underground coal mines. Another object of the present invention is to provide an appropriate layout for extraction of coal from existing pillars with the help of improved mechanised device. Yet another object of the present invention is to provide an appropriate support system in the panel layout in addition to the face support system, Yet another object is to provide a transport layout for the short face equipment system to take the extracted coal to the in bye aide of the panel. The equipment of the present invention is shown in the Fig.1 to Fig.6 of the drawing accompanying this specification. Fig. 1 shows the complete layout of the panel under extraction showing the face equipment layout, conveyor layout from the face to the outbye. Fig. 2 shows the distinct face equipment with self advancing powered supports, shearer, armoured face conveyor, bridging system and the light duty chain conveyor at the face end and also showing the junction support alongwith the gallery supports. Fig. 3 & 4 shows the elevation view of the shearer with its cutter drum, general face supports (chocks), armoured face conveyor and light duty chain conveyor layout. Fig. 5 & 6 shows the special end shield support and its view from one end. Accordingly, the present invention is to provide shortwall mining equipment useful for extraction of pillars in underground coal mines which comprises a series of self advancing powered supports (1) for placement along pillars (2) under extraction, the said pillars under extraction being located within a panel (3) which is rounded by barrier pillars (4), an armoured face conveyor (5) being fixed to the said barrier pillars, characterised in that the said series of supports (1) has a goaf end a support mechansim (6) on a base frame (14) with a side shield (7) including a plate (8) and hanging steel guard (9), a hydraulic ram side arms (10), a front side hook (11) and back side hook (12), the side shield (7) being hung from canopy (13) on the top of the said support mechanism (6), at least two of the hanging steel guards (9) being freely hung from an inner side of the side shield (7), the hydraulic ram side arms (10) being horizontally fixed within the support mechanism (6) to support the side shield (7), the base frame (14) being provided with the front and back side of hooks (11 & 12) to facilitate pulling of the support mechanism (6), the said armoured face conveyor (5) being provided with a shearer (15) having a cutter drum (16) coupled with a centrally located ranging arm (17), the outbye end of the said armoured face conveyor (5) at a right angle to set upon a light duty chain conveyor (18) as a freely advancing bridge, the said light duty chain conveyor (18) is connected to a belt conveyor (19) at the said outbye of the said panel (3). The use of the equipment of the present invention is as follows : Two sets of face equipment (1.5&15) alongwith light duty chain conveyor (18) being in use in front of goaf (20) for extraction of two rows of pillars (2), the said light duty chain conveyors (18) being laid along the cross galleries (21) by the side of the armoured face conveyor (5) face, the open end of the level galleries (22) being supported with skin to skin cogs (23) at the goaf edges (26), the goaf (20) being the extracted areas, the junctions of cross gallery (21) and level gallery (22) being supported by plurality of cogs (23) and hydraulic props, (24) upto two pillars ahead of the goaf, the general level galleries (22) being supported by two rows of hydraulic props (24) and bars (25) upto the two pillar ahead of goaf edge (26), the immediate two cross gallery in front of goaf where the light duty chain conveyors being laid in, being supported by two rows of hydraulic props and bars (24 & 26) on both side of light duty chain conveyor in a staggered manner, the last level gallery (27) at the belt conveyor (19) side of the panel being supported by rows of hydraulic props (24) and girders (28) as goal post support alongwith roof bolts (29) and W-straps (30) as supplemented in between the -rows of girders, the goaf aide end of the said level gallery (27) being supported by at least two chock shields (31) and the Junctions of the same gallery not being supported by the cogs (23) rather by the plurality of hydraulic props (24) with girders (28) placed skin to skin near to the junctions, in the same level gallery (27) the portion of the second light duty chain conveyor covered by a steel structure bridge (32) sloping on its both side, a winch (33) being provided at a distance in the same gallery to be connected by ropes with the hooks (11&12) of the goaf end shield (6). The equipment Of the present invention is mainly a device for cutting of coal from the existing pillars (2) by a cutter (15) and loading of dame by an armoured face conveyor (5). being supported by a series of self advancing powered roof supports (1) in a row such that the length of the combined supports is equivalent to that of the pillar width (say 30 m) . The coal being out by shearer is conveyed by AFC from the face and then off loaded to the light duty chain conveyor which is laid through the cross gallery in front of the face. This light duty chain conveyor (18) transfers coal to the belt conveyor (19) which is laid in the level gallery beyond the barrier pillars and in turn transfer coal to the trunk belt conveyor of main outbye. There is another set of same equipment with a series of Powered roof supports (1) shearer (15) and armoured face conveyor (5) and light duty chain conveyor (18) are placed to cut the second line of pillars in a staggered way such that one set will cut in advance in the front line and they other face will follow lagging behind at two pillars or so in the—second line. The belt conveyor (19) in the level is common for both the equipment set i.e. both the light duty chain conveyors (18) off load coal to the belt conveyor (19) . The chock shield support (6) at the goaf end is a specially designed powered roof support for both the working faces, which can bear the thrust of broken rock peaces from the goaf side and provide safety to the working side, in-spite of rear shield the end chock has one special side shield arrangement (7,8,9&10) at its right hand side. The first line of equipment cut the first rows of pillars under the panel (say 4 pillars), The second line of equipment follow the same for the second rows of pillars in a staggered manner as shown in Fig. 1. At the goaf end of the last level (27) the goaf edge is supported by two nos. of more self advancing powered shield supports (31), instead of cogs as supported in other goaf edges of other levels. Once the extraction is complete for the first row, the equipment are withdrawn with the help of a winch (33) placed in the last level (27) and a bridge (32) placed over the light duty chain conveyor in the second working line. Once the first row pillars are complete the equipment set is withdrawn and installed at the same time to out the next rows of pillars. There is always a flow of coal to the belt conveyor, as one of the equipment set will continue working in the transition period of withdrawal and installation. The junctions are supported by plurality of cogs in combination with orops upto two pillar distance from the goaf edge. The armoured face conveyors is curved at its left hand side and bridging over the light duty chain conveyor such that it can slide upon the intake end of light duty chain conveyor for a few meters to accommodate a few cuts by the shearer, for which shortening is not required. While in operations after a few cuts when the light duty chain conveyor is required to shorten, the inter-linked pans are withdrawn as per requirement in between the two ends of light duty chain conveyor. The withdrawn pans are installed in the third cross gallery simultaneously. The main advantages of the present invention : 1. Initial investment is less with high productivity, 2. Cutting, loading and transporting of coal in extraction of existing Pillars is Possible with the least man power. 3. Possible to achieve continuous flow of coal in the system even in the transition period. 4. Percentage of recovery of coal is very high from the reserve. 5. Roof fall and other strata problem can be well controlled by this system. 6. Working Personnel are more safe in the depillaring operation by using this device and layout. 7. It provides facilities for quicker installation or withdrawal of equipment. 8. It is the most economic method (device and layout) considering productivity, safety and recovery. 9. It is suitable for wide range of coal seams. We claim : 1. Shortwall mining equipment useful for extraction of pillars in underground coal mines which comprises a series of self advancing powered supports (1) for placement along pillars (2) under extraction, the said pillars under extraction being located within a panel (3) which is rounded by barrier pillars (4), an armoured face conveyor (5) being fixed to the said barrier pillars, characterised in that the said series of supports (1) has a goaf end a support mechansim (6) on a base frame (14) with a side shield (7) including a plate (8) and hanging steel guard (9), a hydraulic ram side arms (10), a front side hook (11) and back side hook (12), the side shield (7) being hung from canopy (13) on the top of the said support mechanism (6), at least two of the hanging steel guards (9) being freely hung from an inner side of the side shield (7), the hydraulic ram side arms (10) being horizontally fixed within the support mechanism (6) to support the side shield (7), the base frame (14) being provided with the front and back side of hooks (11 & 12) to facilitate pulling of the support mechanism (6), the said armoured face conveyor (5) being provided with a shearer (15) having a cutter drum (16) coupled with a centrally located ranging arm (17), the outbye end of the said armoured face conveyor (5) at a right angle to set upon a light duty chain conveyor (18) as a freely advancing bridge, the said light duty chain conveyor (18) is connected to a belt conveyor (19) at the said outbye of the said panel (3). 2. Shortwall mining equipment useful for extraction of pillars in underground coal mines substantially as herein described with reference to the drawing accompanying this specification.

Documents:

1515-del-1994-abstract.pdf

1515-del-1994-claims.pdf

1515-del-1994-correspondence-others.pdf

1515-del-1994-correspondence-po.pdf

1515-del-1994-description (complete).pdf

1515-del-1994-drawings.pdf

1515-del-1994-form-1.pdf

1515-del-1994-form-2.pdf

1515-del-1994-form-4.pdf

1515-del-1994-petition-124.pdf