US3512364A

US3512364A - Pillar and stall mining roof support

Info

Publication number: US3512364A
Application number: US737884A
Authority: US
Inventors: Ellis Holland
Original assignee: WILD A G & CO Ltd
Current assignee: AG Wild & Co Ltd; WILD A G & CO Ltd
Priority date: 1967-06-19
Filing date: 1968-06-18
Publication date: 1970-05-19
Anticipated expiration: 1987-05-19
Also published as: GB1182817A

Description

E.- HOLLAND May 19, 1970 PILLAR AND STALL MINING ROOF SUPPORT Filed June 1-8, 1 968 3 Sheets-Sheet 1 -ET Q:

INVENTORZ ELLIS HOLLAND ATTORNEY.

E. HOLLAND PILLAR AND STALL MINING ROOF SUPPORT May 19, 1910 3 Sheets-Sheet 2 Filed June 18, 1968 United States Patent 3,512,364 PILLAR AND STALL MINING ROOF SUPPORT Ellis Holland, Sheffield, England, assignor to A. G. Wild & Co. Limited, Sheflield, England, a British company Filed June 18, 1968, Ser. No. 737,884 Claims priority, application Great Britain, June 19, 1967, 28,189/ 67 Int. Cl. E21d 23/00 US. Cl. 61-45 9 Claims ABSTRACT OF THE DISCLOSURE A self-advancing support having an elongated roof engaging member with a cantilever extension, said member being attached solely by a pivot means to a rear chock and slidably supported by a forward chock during all modes of operation. Hydraulic ram means is provided to effect raising and lowering of the chocks and at the sides of the corresponding bases to advance the support. The member includes spaced beams and a cross plate and levers operate said beams from the forward chock. Arms on said forward chock provide auxiliary support for said member.

This invention relates to a hydraulically operated self advancing mine roof support and is particularly suited for use in seams mined on the pillar and stall system and to a pillar and stall method of mining using such a suport. p For the purpose of explanation of the background of the present invention, reference will now be made to FIG. 1 illustrating in plan a pillar and stall system.

The seams in the pillar and stall mining system are divided into areas known as panels, these panels being say 300 yards square. Main headings 110 or entries are then driven into these panels, the headings being at right angles to the main joint in the coal seams and for example about 18 ft. wide. Cross headings 112 or entries are then driven at right angles to the main headings or entries, these cross headings being about 12 ft. wide. The main headings and cross headings are spaced at about 120 ft. intervals, at centres commensurate with the depth of the Workings and geological conditions thus leaving untouched pillars 114 of mineral for example 100 ft. square, which serve to temporarily support the roofs of the headings.

When all the pillars in the panel have been formed the pillars are extracted by commencing with the pillar furthest from the main mine exit and then extracting subsequent pillars in such a pattern so that the breakdown or caving of the roof advances in a diagonal manner, the advancing front 116 of the caving being knownas the Fracture Line.

Generally the pillars are extracted in slices 118, each slice being for example about 9 ft. wide, starting from the goaf side and working towards new pillars. As extraction proceeds the roof has to be supported and when the slice has been finished the supports have to be advanced.

Modern practice is for the extraction to be carried out by machinery, for example a cutting machine having rotary cutting heads at its forward end and a self-loading conveyor at its rear end. In operation the conveyor feeds the cut mineral into a self-propelled mine car or shuttle car.

The normal practice of supporting the roof is to have wooden chocks nearest the goaf and then between these wooden supports and the pillar are placed simple props and roof bars to provide support over the working road- Patented May 19, 1970 ice way. This system of supporting is neither self-advancing nor normally sufficiently wide to allow the passage of shuttle cars.

To briefly summarize the present invention, We provide a fluid-operable self-advancing mine roof support particularly for use in pillar and stall mining comprising a rear fluid-operable chock and at least one other fluidoperable chock, in which a roof-engaging member of substantial length is pivotally attached only to the rear chock at or towards the top thereof and extends forwardly adjacent and in slidable relationship during all modes of operation with a canopy unit provided at the top of the chock or each other chock, the bases of the rear chock and one of the other chocks being connected by a double-acting fluid-operable ram for use in advancing the support.

In such a mine roof support comprising a forward and a rear chock, the forward chock can be advanced independently of the rear chock. The advancing means of the support is formed by double acting hydraulic rams connected between said legs. The rear ends of the cylinders of said rams may be pivotally connected to the sides of the base of the front leg and the outer ends of the piston rods of said rams may be pivotally connected to the sides of the base of the rear leg. The roof member may be for example two parallel beams, one on each side, which extend forwardly and slidably pass over supporting wings within the canopy unit on the top of the front chock. The two said beams extend a considerable distance, for example 9 feet in front of the forward leg and are joined together at the forward end of the beams by a large cover plate.

In one embodiment of the invention, two L-shaped levers are pivotally connected to the top of the front leg, the long arms of the levers extending forward. These arms are joined together at their ends by a supporting bar, which passes underneath the aforesaid beams.

Pressure capsules may be provided to act on the short arms of the L-shaped levers which in turn forces the supporting bar onto the underside of roof beams and thus forces connecting cover plate into contact with mine roof.

The invention will be better understood from the following particular description given by way of example with reference to the accompanying drawings in which:

FIG. 1 is as stated, a plan view of a panel of a seam mined by the room-and-pillar system of mining.

FIG. 2 is an elevation of one form of roof support according to the invention.

FIG. 3 is a diagram showing the sequence of operations used to advance the supports in accordance with the method of the invention.

FIG. 4 is a cross-sectional view taken along line IV-- IV of FIG. 2.

FIG. 1 shows one panel of a seam which has been divided by lateral roadways or main entries and longitudinal roadways or cross entries. The main entries may be 18 feet wide whilst the cross entries may be 12 feet side. Pillars of coal are formed by the said system of tunneling which may be feet square.

The pillars, shown in dotted lines and hatched over as at 122 are ones that have been extracted and the roof allowed to cave-in to form goaf. Pillars are extracted in turn in such a manner as to form of diagonal fracture line.

The chain dotted lines and serial Nos. 1-10 shown on one of the pillars (114a) indicate how the mineral, e.g. coal will be extracted in strips of about 10 feet width, the numbers being the order in which the strips are worked.

Now, referring to FIG. 2, this shows one form of roof support according to the invention comprising a rear hydraulically extensible rear chock 1 sitting on a base unit 2 and carrying a canopy unit 3 at its upper end. A front hydraulically extensible chock 4 sits on a base unit 5 which is similar to base unit 2 but of opposite hand, and also carries a canopy unit 6. Two double acting advancing rams 7 are situated one on each side of the legs 1 and 4. The cylinders of these rams are pivotally connected at 8 to a clevis 9, the opposite end of which is pivotally connected at 10 by means of a pin in a vertically slotted hole to a bracket 11. The bracket 11 is rigidly attached to base 5. The piston rods of the rams 7 are similarly connected to rear base unit 2.

Two roof bars members 12 situated one on each side of legs 1 and 4 are pivotally connected at 13 to rear canopy unit 3. These bars 12 extend a considerable distance, for example 9 feet in front of leg 4 and are joined together by roof bar cover plate 14 to form a cantilever extension. This is in contrast to conventional constructions of roof support for longwall mining in which the roof bars normally extend only about 3 ft. in front of the forward leg. The members 12 extend forwardly through and in slidable relationship with the canopy unit 6.

The two L-shaped levers 15 are pivotally connected at 16 to brackets 17. The longer arms 15a of said levers extend forwardly and are joined together by a support bar 18. Pressure capsules 19, i.e. small single acting rams, are situated one on each side of leg 4. The cylinders of said capsules are pivotally connected at 20 to a bracket 21 Whilst the pistons of said capsules are pivotally connected at 22 to the shorter arm 15b of L-shaped levers 15.

When pressure capsules 19 are pressurised they exert a force on the shorter arms of levers 15 and thus cause support bar 18 to be forced onto the undersides of roof bars 12 thus causing said bars to pivot about pivot 13 until the roof bar cover plate 14 contacts the roof of the mine. Removing pressure from capsule 19 causes the weight of

members

12, 14 and 15 to compress the capsule 19, thus lowering the bars 12 until they come to rest on supporting arms 23, which protrude from undersides of canopy unit 6 as shown in FIG. 4.

With capsules in compressed (i.e. retracted) condition, the front leg 4 can be lowered from the roof, leaving rear leg 1 still set to the roof, and then rams 7 are operated to extend and push leg 4 towards the coal face a distance equal to half the cantilever length. The cantilever length will be of the order of 9 ft. and therefore the stroke of the rams 7 will be about 4'6". When leg 4 has been fully pushed over it is reset to the roof and then rear leg 1 lowered from the room. Rams 7 are then operated to compress and pull leg 1, plus attached roof bars 12, a distance of 4'6" towards leg 4. Leg 1 is then reset to the roof. To move support over the full 9 ft. width of roadway the above operation must be carried out twice. After support has been fully moved over capsule 19 is re-pressurised and cover plate 14 reset to the roof. To assist lowering of legs 1 and 4 from the roof, retraction rams 24 are positioned on each leg.

To offer the greatest support to the roof the supports are positioned at about 4 ft. centres and when the cut has been taken the supports are advanced in pairs using a sequence according to the invention that ensures maximum roof support throughout the advancement. FIG. 3 shows the sequence of operations involved in the method according to the invention in which the full lines indicate the position of the first support of the pair and the dotted lines indicate the position of the second or adjacent support in relation to the first support. The numbers shown in FIG. 3 correspond to the sequence numbers specified in the following paragraphs.

The sequence of operations in accordance with the method of mining according to the invention, to advance a pair of supports is as follows:

(1) Cantilever extension and front leg of first support are lowered whilst second support remains fully raised.

(2) Advancing rams of first support are operated to push front leg forward and then front leg reset to the roof.

(3) Cantilever extension and front leg of second support are lowered then advancing rams of second support are operated to push front leg forward and then front leg reset to the roof.

(4) Rear leg of first support is lowered and advancing rams operated to pull rear leg and cantilever extension forwards. Rear leg then reset to the roof.

(5) Rear leg of second support is lowered and advancing rams operated to pull rear leg and cantilever extension forward. Rear leg then reset to the roof.

(6) Front leg of first support is lowered and advancing rams operated to push front leg forwards and then front leg reset to the roof.

(7) Front leg of second support lowered and advancing rams operated to push front leg forwards and then front leg reset to the roof.

(8) Rear leg of first support is lowered and advancing rams operated to pull rear leg and cantilever extensions forwards. Rear leg and cantilever extension are both reset to the roof. The first support has now been fully advanced.

(9) Rear leg of second support is lowered and advancing rams operated to pull rear leg and cantilever extension forwards. Rear leg and cantilever extension are both reset to the roof. The second support has now been fully advanced.

The above sequence of operations are repeated on the next pair of supports and so on down the face until all sulpports have been fully advanced. The supports can be advanced as the cut proceeds or When the cut has been finished.

Each support will be controlled independently, the control panel being positioned on the front leg so as to always be furthest away from the goaf.

The support system could be automatically advanced by a remotely operated control system.

The support disclosed herein, while particularly suitable for room-and-pillar work, could be used in any type of mining where a deep cut is required to be taken. such as would arise if using a wide web buttock mining machine.

I claim:

1. A fluid-operable self-advancing mine roof support particularly for use in removing wide webs of mineral comprising a rear base, a rear chock mounted on said rear base, a base located forwardly of said rear base, a forward chock mounted on said forwardly located base, fluid means for operating said chocks, an integral roof engaging member of substantial length solely attached to said roof support by pivot means adjacent the top of said rear chock, said member extending adjacent the forward chock, means for slidably supporting said member by said forward chock during all modes of operation, the roof engaging member having sufiicient length to extend beyond said forward chock to form a cantilever extension, and the bases of the rear chock and the forward chock being connected by at least one double-acting fluid-operable ram for use in moving said support.

2. A support according to claim 1 in which said fluid means includes hydraulic ram means connected between the topof at least one of said chocks and the corresponding one of said bases to effect raising and lowering of the chock.

3. A support according to claim 1 in which said supporting means includes adjustable means on said forward chock for raising and lowering said extension.

4. A support according to claim 3 in which said adjustable means comprises an L-shaped lever pivotally carried by the forward chock to engage the cantilever extension of the roof engaging member, and a fluid-operable ram is provided for pivoting the lever to urge said extension against the roof.

5. A support according to claim 3 wherein said supporting means further includes an arm carried by said forward chock adjacent the top thereof for slidably engaging said cantilever extension from below whereby said extension is additionally supported by said forward chock when said adjustable means is in the lowered position.

6. A support according to claim 1 wherein said doubleacting fluid-operable ram is connected between the forward and rear chock bases at one side thereof, and an additional double-acting fluid-operable arm is provided at the opposite side of said base to aid in moving said support, said rams being pivotally connected to said bases at both ends.

7. A support according to claim 1 wherein said roof engaging member comprises two parallel beams connected to the free ends by a cross plate.

8. A support according to claim 7 wherein said sup- 20 porting means includes adjustable means on said forward chock for raising and lowering said extension, said adjustable means comprises L-shaped levers pivotally carried by the forward chock to engage said beams, a cross bar to connect said levers and fluid-operable ram means is provided for pivoting the levers tourge said extension against the roof.

9. A support according toclaim 8 wherein said supporting means further comprises protruding arms extending from the sides of said front chock for auxiliary sliding support of said beams when said levers are lowered.

References Cited UNITED STATES PATENTS 3,372,551 3/1968 Von Hippel 6145 FOREIGN PATENTS 202,954 4/ 1959 Austria. 719,170 11/1954 Great Britain. 882,933 11/1961 Great Britain. 1,427,549 12/ 1965 France.

942,384 5/ 1956 Germany. 140,778 1/1961 U.S.S.R.

DENNIS L. TAYLOR, Primary Examiner US. Cl. X.R. 248357