GB2045325A

GB2045325A - Mine Roof Support System

Info

Publication number: GB2045325A
Application number: GB8007180A
Authority: GB
Original assignee: Fletcher Sutcliffe Wild Ltd
Current assignee: Fletcher Sutcliffe Wild Ltd
Priority date: 1979-03-10
Filing date: 1980-03-03
Publication date: 1980-10-29
Also published as: GB2045325B

Abstract

A mine roof support system comprises a plurality of hydraulically powered, self-advancing supports 1- 5 located along one side of an armoured conveyor 6, a double-acting advancing ram 12 connected between a base means 10 of each support 1- 5 and the conveyor 6, and a double- acting advancing ram 18 extending generally in the intended direction of advance of the supports and connected between a rearward end 8 of a roof beam 17 of each support 1- 5 and a forward end 7 of a roof beam 17 of an adjacent support 1-5. Exhaust fluid from the full base side of a base advancing ram 12 is either fed to the full bore side of both adjacent roof beam advancing rams 18, or to the full bore side of one and the annulus side of the other. In an inclined seam the funnel ends of the roof beam rams 18 are connected to the uphill support and the full bore side of the base ram 12 is connected to the full bore side of the downhill roof beam ram 18. <IMAGE>

Description

SPECIFICATION Mine Roof Support System This invention relates to a mine roof support system incorporating a plurality of hydraulically powered, self-advancing mine roof supports located, in accordance with conventional longwall mining practice, along the goaf side of an armoured conveyor extending along the mineral face.

In the conventional system the supports are attached to the conveyor by one or more doubleacting advancing rams connected between base means of the supports and the individual pans of the conveyor, the ram or rams being actuated in one direction, with the support involved being staked between the mine roof and floor, to advance the individual conveyor pans in accordance with the rate at which mineral is being removed from the face and in the reverse direction, with the support involved being retracted, to advance the support to the previously advanced conveyor, the reaction for this movement being taken by the conveyor.

Normally a single central ram is provided in the base means, but the use of two rams mounted outboard of the base means is also known.

However, whilst such arrangements have proved generally satisfactory for the weight and dimensions of previous supports e.g. which possibly had a maximum height of 6 to 8 feet, with a demand for supports of say 1 6 feet and of increased weight, difficulties are encountered during support advance due inter alia to the fact that when a support is being advanced the advancing force on it is applied solely to its base means which results in a certain instability and secondly the conveyor is often pulled- back towards the support rather than the support being pulled forwards to the conveyor. In addition, present trends are towards what is termed "contact advance" whereby the roof beam is not retracted clear of the roof during advance of the support, but maintains a relatively light, frictional engagement with the roof during advance.

Furthermore, when working an inclined mineral seam, it has been known to locate relatively small hydraulic rams between adjacent supports, and at roof beam level, for purposes of positional correction and stability of one support with respect to its adjacent support.

According to the present invention, a mine roof support system comprises a plurality of hydraulically powered, self-advancing roof supports located along one side of an armoured conveyor, a double-acting advancing ram connected between a base means of each support and the conveyor, and a double-acting advancing ram extending generally in the intended direction of advance of the support and connected between a rearward end of a roof beam of each support and a forward end of a roof beam of an adjacent support.

Thus, the supports in accordance with the present invention are advanceable by applying advancing forces not only at their base means, but also at the roof beams, the advancing support thereby reacting partly on the conveyor and partly on at least one adjacent support, or in a preferred arrangement on the adjacent supports to both sides of the support being advanced, the adjacent support(s) being of course staked in position in accordance with conventional practice after having been previously advanced or before being subsequently advanced.

Although separate fluid control arrangements could be employed to activate the advancing ram associated with the base means (hereinafter referred to as "a base ram") and the advancing rams associated with the roof beams (hereinafter referred to as "a roof ram"), it is preferred to employ a hydraulic system whereby exhaust fluid from a base means ram is fed as pressure fluid to both adjacent roof beam rams, all the rams having the same working cross-sectional areas. In detail, during the advancing of a support by admitting pressure fluid to the annulus side of its base ram, the full bore side of its base ram is connected to the full bore side of an adjacent roof ram at one side of the support > .and the annulus side of an adjacent roof ram at the other side of the support.

If an inclined seam is being worked, further advantage may be gained by having all the roof beam rams-located parallel to one another, the connection at the rearward of one roof beam being downhill from the connection of that same ram to the forward end of the adjacent, uphill support, with this arrangement, the full bore side of each base ram would be connected to the full bore side of an adjacent, downhill, roof ram, Alternatively, the roof beam rams could be arranged in non-parallel fashion.

The invention will now be described, in greater detail, by way of example, with reference to the accompanying drawings, which is a diagrammatic plan view of the mine roof support system according to the present invention.

A plurality of hydraulically powered, selfadvancing mine roof supports 1 to 5 are arranged side-by-side, in the conventional manner, along an armoured, scraper chain conveyor 6, made up of a plurality of pans articulated together end-toend, which conveyor 6 extends along a longwall mineral face (not shown).

Each support 1 to 5 has a forward end 7 adjacent the conveyor 6 and a rearward end 8 remote from the conveyor 6. Each support also includes a plurality of hyraulically extensible chock legs 9, which are indicated in chain dotted line on support 2 only. Each support also has a rectangular base means 10 supporting lower ends of the chock legs 9 and seating on a mine floor 11. Each base means 10 is attached to the conveyor 6 by a double-acting hydraulic ram 12 (the base ram) having a piston rod 13, articulated to a sidewall of the conveyor 6, and a cylinder 14.

Thus, each ram 9 has an annulus side 15 and a full-bore side 16.

A roof beam 17, only portions of which are shown, engages the mine roof (not shown) and is of similar rectangular dimensions as the base means 10, and is carried by the upper ends of the chock legs 9.

A double-acting advancing ram 18, (the roof ram) extending generally in the intended direction of advance of the supports 1 to 5, is pivotally connected at 1 9 to a rearward end 8 of the roof beam 1 7 of one support, and pivotally connected at 20 to a forward end of an adjacent support.

Each roof ram 18 has a piston rod 21 and a cylinder 22. Thus, each roof ram 18 has an annulus side 23 and a full-bore side 24.

The full-bore side 16 of each base ram 9 is connected by a conduit 25 to the full-bore side 24 of an adjacent roof ram 18. The annulus side 23 of each roof ram 18 is connected by a conduit 26 and through a valve 27, to the annulus side of a roof ram 1 8 at the other side of the support being advanced. Thus, fluid exhausted from the full bore side of the base ram 9 of a support being advanced, is employed to actuate both roof rams 1 7 to each side of that support. Further control valves 28 and 29 are also provided on each support for controlling the extension and retraction of each base ram 9, in the well-known manner.

Claims

1. A mine roof support system comprising a plurality of hydraulically powered, self-advancing roof supports located along one side of an armoured conveyor, a double-acting advancing ram connected between a base means of each support and the conveyor, and a double-acting advancing ram extending generally in the intended direction of advance of the support and connected between a rearward end of a roof beam of each support and a forward end of a roof beam of an adjacent support.

2. A system as claimed in Claim 1, wherein separate fluid control arrangements are employed to activate the advancing ram associated with the base means and the advancing rams associated with the roof beams.

3. A system as claimed in Claim 1, wherein a hydraulic system is employed whereby exhaust fluid from a base means ram is fed as pressure fluid to both adjacent roof beam rams, all the rams having the same working cross-sectional areas.

4. A system as claimed in Claim 3, wherein the full bore side of a base ram of a support being advanced is connected to the full bore side of an adjacent roof ram at one side of the support, and to the annulus side of an adjacent roof ram at the other side of the support.

5. A system as claimed in any one of Claims 1 to 4, wherein all the roof beam rams are located parallel to one another.

6. A system as claimed in any one of Claims 1 to 5, in circumstances where an inclined mineral seam is involved, wherein the connection at the rearward end of one roof beam is downhill from the connection of that same ram to the forward end of the adjacent, uphill support.

7. A system as claimed in Claim 6, wherein the full bore side of each base ram is connected to the full bore side of an adjacent, downhill, roof ram.

8. A mine roof support system substantially as hereinbefore described with reference to the accompanying drawing.