GB1594032A - Method and apparatus for lagging the roof of a mine roadway or tunnel - Google Patents

Description

PATENT SPECIFICATION

( 11) 1594032 ( 21) Application No 8754/80 ( 22) Filed 16 Sept 1977 ( 62) Divided out of No 1 594031 ( 31) Convention Application Nos.

2641 785 ( 32) Filed 17 Sept 1976 in 2 641 855 ( 33) Fed Rep of Germany (DE) ( 44) Complete Specification published 30 July 1981 ( 51) INT CL 3 E 21 D 23/00 ( 52) Index at acceptance E 1 P 2 E 1 B 2 E 5 D 2 E 5 L 2 E 5 M 2 E 7 2 E 8 E 1 F 43 A 43 B ( 54) A METHOD AND APPARATUS FOR LAGGING THE ROOF OF A MINE ROADWAY OR TUNNEL ( 71) We, SALZGITTER MASCHINEN AKTIENGESELLSCHAFT, a German joint stock Company, of 3327 Salzgitter-Bad, Federal Republic of Germany, do hereby declare the invention, for which we pray that a Patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following Statement:-

This invention relates to a method of lagging a roof of a gallery in a mine roadway or tunnel, comprising supporting, on roofsupporting members of a self-advancing mine roadway or tunnel roof support having an arched frame spanning across the width of the mine roadway or tunnel, lagging mats which are inter-connected to provide a strip of lagging matting in the longitudinal direction of the mine roadway or tunnel, each adjacent pair of lagging mats in the longitudinal direction being interengaged in such a manner that tensioning the strip of matting in the longitudinal direction tightens the interengagement between the mats, the roof-supporting members being mounted for movement upwardly into or downwardly out of positions provided bracing support of the roof of the mine roadway or tunnel.

Such a method will hereinafter be referred to as "a method of the kind referred to".

The invention also relates to a selfadvancing mine roadway or tunnel roof support.

In German Published Patent Application (DOS)No 2,363,488, there is described an advancing mine roadway or tunnel support structure comprising interconnected frames each comprising two side frame parts, one associated with each side wall of the mine roadway or tunnel, and a roofing frame part which is connected to the side frame parts and which can be braced against the roof of the mine roadway or tunnel Roofsupporting members are pivotally connected to the roof frame part and can be moved in and out by hydraulic height adjustment means on the frame enabling them to be moved into and out of, respectively, bracing engagement with the roof of the mine roadway or tunnel If it is necessary to lag the roof, then lagging mats must first be fastened together and supported on the roofsupporting members Then the fastenings must be made taut by moving the lagging mat relative to the other lagging mat(s) in 55 the longitudinal direction of the mine roadway or tunnel, and only then can the lagging mats be placed in position by extending the roof-supporting members out against the roof of the mine roadway or tunnel How 60 ever, there are two main disadvantages associated with this known method of working Firstly only a small amount of tension can be exerted on the strips of matting prior to them being pressed against the roof of the 65 mine roadway or tunnel This means that there is a danger that the fastenings between the mats will be released when the permanent mine roadway or tunnel support structures are being installed Secondly, the 70 known method of working is relatively expensive.

The present invention seeks to provide a method of lagging the roof of a mine roadway or tunnel in which a strip of matting, or 75 several strips of matting which are each made up of several lagging mats fastened together, are tensioned as they are moved against the roof of the mine roadway or tunnel This enables the fastenings between 80 adjacent lagging mats in the longitudinal direction of the mine roadway or tunnel to be adequately tensioned so that the lagging mats are no longer released during installation of the permanent support structure, 85 even when the roof pressure has not been applied or is not at its full level.

According to one aspect of the present invention, a method of the kind referred to is characterised in that the roof-supporting 90 members are given a component of movement in the longitudinal direction of the mine roadway or tunnel when they are moved upwardly into positions to brace the lagging matting against the roof of the mine 95 roadway or tunnel thereby tensioning the matting in the longitudinal direction and tightening the inter-engagement between adjacent lagging mats in the said longitudinal direction 100 rq um 1 594 032 The method according to the invention has the advantage that a greater degree of mechanisation for the insertion of the lagging is made possible In particular, the lagging matting does not have to be pulled taut manually, as was hitherto necessary in previous known methods, either before or after having been pressed against the roof of the mine roadway or tunnel Moreover, the lagging matting is brought into its final position largely automatically and therefore this does not depend on the attentiveness of the workforce This gives a great reliability in the installation of the lagging matting since it is less likely that adjacent lagging mats in the longitudinal direction of the mine roadway or tunnel will become disengaged or unfastened when the permanent mine roadway or tunnel support structure is installed.

A preferred type of lagging mat with which it is possible to provide a strip of matting which can be tensioned in the longitudinal direction of the mine roadway or tunnel on tensioning of the strip of matting, is a type of lagging mat described in the specification of German Published Patent Application (DOS) No 2,044,041 This specification describes a lagging mat in the form of a mesh consisting of a plurality of parallel cross-rods and longitudinal rods having ends bent into loops designed to inter-engage with the looped ends of the longitudinal rods of an adjacent mat so that each pair of inter-engaged looped ends is interlaced in the manner of a reef knot This known reef knot type of fastening is extremely secure.

Preferably, each roof-supporting member is moved along the arc of a circle, having an axis disposed transversely to the said longitudinal direction, as it is moved into its position to provide bracing support of the roof of the mine roadway or tunnel In this way, it is possible to determine geometrically both the size of the component of movement in the said longitudinal direction, and the size of the upwards movement, of each roof-supporting member.

According to another aspect of the present invention, a self-advancing roadway or tunnel roof support comprising a support unit having an arched frame adapted to span across the width of a mine roadway or tunnel, and at least one actuating mechanism mounted on the frame and carrying one or more roof-supporting members extending forwardly and rearwardly from the frame for supporting lagging matting thereon, the or each actuating mechanism being actuable for moving the or each roof-supporting member carried thereby upwardly towards or downwardly away from a roof of a mine roadway or tunnel positioned above the support, is characterised in that the roofsupporting member(s) carried by the or each actuating mechanism is (are) given a component of movement parallel to the direction of advancement of the support on actuation of the actuating mechanism to move the roof-supporting member(s) 70 towards a roof of a mine roadway or tunnel positioned above the support In this manner, any lagging matting positioned on the roof-supporting members can be frictionally moved against the roof of the mine roadway 75 or tunnel in the longitudinal direction of the mine roadway or tunnel as the lagging matting is braced against the roof This frictional movement causes the lagging matting to be tensioned thereby tightening inter 80 engagement between adjacent lagging mats of the lagging matting.

Conveniently, the or each actuating mechanism comprises a first pivot arm pivotally connected to the frame about a 85 first axis and carrying one or more of the roof-supporting members, and a second pivot arm, in the form of a variable thrust piston mechansim, pivotally connected adjacent one of its ends to the frame about a 90 second axis and pivotally connected adjacent its other end to the first arm about a third axis, the first, second and third axes being parallel to each other and extending transversely to the direction of advancement 95 of the support.

The invention will now be described, by way of example, with reference to the accompanying drawing, in which:Figure la is a side view of the lower part 100 of a self-advancing mine roadway or tunnel roof-support according to the invention, Figure lb is a partly sectioned side view of the upper part of the support shown in Figure la, 105 Figures 2 a and 2 b are end views of the roof support of Figure la; Figure 2 a showing one side and the top of the support and Figure 2 b showing the other side of the support, 110 Figure 3 gives three illustrations arranged one under the other each showing schematically in side view two phases of the advancing process of the roof support shown in Figures la, lb and 2 a, 2 b, 115 Figure 4 shows in plan three roof supports, each as shown in Figures la, lb, 2 a and 2 b arranged adjacent to each other and positioned on a curve, Figure 5 shows in side view three illustra 120 tions of the advance of an embodiment of a self-advancing mine roadway or tunnel roof support according to the invention when contact with the roof has been lost, Figure 6 shows, in side view, another 125 embodiment of a self-advancing mine roadway or tunnel roof support according to the invention and having lagging mattings supported thereon, and Figures 7 a and 7 b show in side view and 130 1 594 032 plan, respectively, how an end of a longitudinally extending rod of a lagging mat is inter-engaged with an end portion of a longitudinally extending rod of an adjacent lagging mat.

Figures la and lb show a self-advancing mine roadway or tunnel roof support, generally designated by the reference numeral 1, comprising two support units 2 and 3 The support units are of identical construction in their main parts so that it will suffice initially to describe only one of these support units.

Each support unit has two frames 4 and 5 which each form a curved or arched segment which consists of a continuous I-structural section bent to correspond to the contour of a roof of a mine roadway or tunnel The two frames 4 and 5 are linked together by means of connecting pieces 6 Roof-supporting members in the form of frame capping plates 7 are arranged at intervals around the contours of the frames 4, 5 and are connected thereto by means of actuating mechanisms Each actuating mechanism comprises a first pivot arm 9 pivotally connected to the frame 5 about a first axis 13 and carrying one of the frame capping plates 7, and a second pivot arm in the form of a variable length thrust piston drive mechanism 11, pivotally connected adjacent one of its ends to the frame 4 about a second axis 12 and pivotally connected adjacent its other end to the first arm 9 about a third axis 8 The axes 13, 12 and 8 are parallel to each other and extend transversely to the direction of advancement of the support 1.

By actuating the thrust piston drive mechanism 11, the arms 9 are moved in arcs of circles so that the frame capping plates 7 also describe arcs of circles as they move forwardly and upwardly to enable a lagging matting (not shown) supported thereon to be braced against the roof of a mine roadway or tunnel.

The frame capping plates 7 of the support unit 2 are arranged in such a way that the frame capping plates 18 of the support unit 3 slot in between the frame capping plates 7, and the capping plates 7 and 18 partially overlap.

The support 1 suitably constitutes one of a plurality of similar supports arranged one behind the other to provide a support system Although not shown, any adjacent pair of supports are so arranged that the capping plates 18 of the rear support unit 3 of the leading support 1 overlap the capping plates of the front support unit (not shown) of the trailing support (also not shown), and that these capping plates 18 slot in, or inter-fit, between the capping plates of the other support.

As can be seen from the illustration in Figure 2 a and 2 b, the frames 4 and 5 are joined by means of gusset plates 20 and 21, together with a heavy baseplate 22 which is attached to a box-type construction 23 On the outer face of the box-type construction 23 nearest to the roof of the mine roadway or tunnel there are two substantially vertical 70 walls which are made of heavy metal plates 24 and 25, respectively These plates are fitted at the bottom with a baseplate 26 This construction forms a rigid guide 27 on the front support unit 2 and a correspondingly 75 rigid guide 28 on the rear support unit 3 It should be noted that the baseplate 26 in the rigid 27 on the front support unit slopes from the top rear towards the front bottom, whilst in the guide 28 on the rear support 80 unit 3 it slopes from the top front towards the rear bottom.

Between the two perpendicular plates of the guide units 27 and 28 a rail 29 is arranged The rail 29 is fixed to the front 85 support unit 2 by means of a pivot 30 The pivot, which can be seen in Figure 2, consists of a pin 31, which passes through the crosspiece 32 of the rail as well as the two side walls 24 and 25 The rail 29 can therefore be 90 deflected about the pivot 30 in a generally vertical plane The amount of its deflection is determined by a thrust piston drive unit which acts on the free end 35 of the rail 29.

A shoe 36 is attached to the piston rod end 95 of the thrust piston drive unit and comprises a crossbolt 38 which is guided in a substantially vertical straight guide formed by an elongate hole 37 provided in each of the vertical walls 24 and 25 The thrust piston 100 drive unit is pivotably suspended by its cylinder 41 via a horizontal pin 39 in brackets 40 and 42 The rail can therefore be movably supported on its end 35 with its upper face 44 under the shoe 36 without any 105 moment being transmitted to the thrust piston drive unit.

On the rear rigid guide 28 of the support unit 3 the rail 29 is guided by means of guide means 48 The guide means 48 is formed 110 from two horizontal link pins 49, 50, as can be seen in Figure 2 b The upper face 51 of the end 35 of the rail 29 is supported on the link pin 50, whilst the lower face 53 of the end 35 ' of the rail 29 is supported on the 115 lower link pin 49 Accordingly, the rail 29 can turn or be deflected relative to the support unit 3 in the guide means 48 about a horizontal axis and about a vertical axis and can also be slidingly displaced relative to the 120 support unit 3 in the guide means 48 formed by the link pins 49 and 50.

Behind the guide means 48 formed by the pins 49 and 50 the rail 29 is again supported on a shoe 55 of a thrust piston drive unit 125 which is not shown in Figures la, lb, 2 a or 2 b This thrust piston drive unit is arranged and constructed like the thrust piston drive unit 41 of the front support unit 2 It is therefore similarly suspended and is sup 130 1 594 032 ported on the upper face of the end 35 ' of the rail 29.

In each box-type construction there are brackets 60 to take horizontal linkage bolts 61, by which cylinders 62 of each two props or supports 63, 64 are pivotably mounted; the extensible parts 65 and 66 of the latter being connected at their ends to base-plates 67 on which the extensible parts 65 and 66 are supported via ball ends 68 and 69 The arrangement of the props 63 and 64 is the same in both support unit 2 and support unit 3, so that a description of this relative to support unit 3 is unnecessary.

The props 63 and 64 are also fitted so that they can be deflected 50 out of the vertical in any direction, as Figures la and 2 a show at 57 This construction allows each unit to adapt to differences in the level of the floor of the mine roadway or tunnel.

The advancing mechanism in the construction example shown consists primarily of a thrust piston drive unit 70, appertaining to each of the rails 29, the cylinder of which is given the reference 71 or 72 respectively (Figures la and 2 b), its piston rod being designated 73 The piston rod of each thrust piston drive unit is linked with a clevis 74 via a horizontal link bolt 75 to a bracket 76 on the rigid guide 27 concerned, whilst the cylinder 71, 72 is linked via a forked bracket 77 by means of a similarly horizontal link bolt 78 to the rear rigid guide 28.

In addition to the two thrust piston drive units 70, the advancing mechanism comprises another thrust piston drive mounted at the top of the support at 80, and shown at 81.

The advance movement of the above described support 1 is shown schematically in Figures 3 and 4 In the upper illustration in Figure 3 the synchronous expansion or outwards movement of the thrust piston drive units 71, 72 and 81 is represented The front support unit 2, with its capping plates 7 lowered, advances as the piston rods of the drive units 71, 72 and 81 move out, the rear support unit 3 being braced against the roof of the mine roadway or tunnel by its capping plates 18 (position shown on the right in the upper illustration in Figure 4) When the piston rods of the drive units 71, 72 and 81 are fully extended, the capping plates 18 are lowered, the support unit 2 is held fast by the bracing of its capping plates 7 against the roof of the mine roadway or tunnel, and the piston rods of the drive units 71, 72 and 81 are moved in causing the rear support unit 3 to advance towards the front support unit 2.

If a fault in the floor of the mine roadway or tunnel, as indicated at 90 in the phase shown on the left in the central illustration, is to be traversed downwards, then the piston rod of the thrust piston drive unit 56 is moved in and the piston rod of the thrust piston drive unit 41 is moved out This causes the rail 29 to be deflected about the horizontal axes of its pivot 30 and the guide means 48, in which the rail 29 is in turn 70 guided By moving the thrust piston drive units 71, 72 and 81 out, the support unit 2 can then move with the rail 29 as the latter slides in the guide means 48.

Conversely, to overcome a step 91 75 upwards (right-hand phase in the central illustration in Figure 3), the piston rod of the thrust piston drive unit 56 is moved out and the piston rod of the thrust piston drive unit 41 is moved in, the rail 29 being 80 deflected upwards so that the support unit 2 can be moved forwards and upwards by movement on the two rails arranged at the sides of the support 1.

In the lower illustration in Figure 3 varia 85 tions in the slope of the mine roadway or tunnel are indicated at 92 and 93 In order to be able to set the support units 2 and 3 of the support perpendicular to the stratification, the thrust piston drive units are moved 90 out differently.

To overcome an upwards deflection 92 in the slope, the piston rod of the upper thrust piston drive unit 81 is moved out by a lesser amount than the piston rods of the thrust 95 piston drive units 71 and 72, so that the support unit 2 is deflected about the pivot At the same time, by rm 1 oving out the piston rods of the thrust piston drive units 56 and 41 the necessary incline of the rails 100 29 is produced, so that the support 1 can be moved on the path produced by the rails 29.

On the other hand, with a variation in the slope corresponding to 93 in the right-hand phase in the lower illustration in Figure 3, 105 the upper thrust piston drive unit 81 is moved out more than the thrust piston drive units 71 and 72 arranged on the side walls.

The position of the rails 29 is again produced by the extended position of the thrust 110 piston drive units 56 and 41.

As was explained with reference to the lower illustration in Figure 3, by moving the piston rods of the thrust piston drive units 71 and 72 and/or 81 by different amounts, 115 curves can also be traversed, as is shown in Figure 4.

An embodiment is shown in Figure 5 which makes an advancing movement possible without contact with the roof of the 120 mine roadway or tunnel For this purpose, an extensible support element 100 is arranged on the front support unit 2 of the support 1 The support element 100 comprises a thrust piston mechanism, the cylin 125 der of which is attached at 101 to the front of the rigid guide 27, the piston rod 102 being fitted with a skid 103 in the form of a shoe which can be supported on the floor 104 The rear end 35 ' of each rail 29 is in 130 1 594 032 turn fitted with an extensible support element or mechanism 105, the cylinder of which is attached at 106 to the outer end of the rail, whilst the piston rod 107 is fitted S with the guide skid 108 and can rest on the floor 104.

The upper illustration in Figure 5 shows the advance movement of the rear support unit 3 Here, the extensible support element or mechanism 105 is operated by the extension of its piston rod 107 The rail is thus supported and forms a bridge on which the rear support unit 3 can advance forwards with the props 65, 66 retracted by moving the piston rods into the thrust piston drive units 81 and 71, 72.

The central illustration in Figure 5 shows the advance movement of the front support unit 2 Here, the piston rod 102 of the extensible support element 100 is extended and is supported on the floor 104 By moving the piston rods out of the cylinders of the thrust piston drive units 81 and/or 71 and/or 72, the rail 29, together with the front support unit 2, can move forwards, guided through the two link pins 49 and 50 In this instance the extensible support element or mechanism 105 is moved in or contracted.

The lower illustration in Figure 5 shows the two extensible support elements 100 and 105 contracted This state again enables the support units 2 and 3 to be employed with their capping plates 7 and 18, respectively, extended.

Figure 6 shows a schematic view of another embodiment of a self-advancing mine roadway or tunnel roof support according to the invention comprising an arched frame 203 having two support structure sections 201 and 202 spaced apart from each other in the direction of advancement of the roof support The two structure sections 201 and 202 are joined by a connecting plate 204 so that a stable structure is formed The frame 203 has an advance mechanism which is not shown, and, if required, bydraulic supports which can be extended and retracted.

The frame 203 forms the support for an actuating mechanism given the general designation 205 The actuating mechanism 205 has a link arm 206 which is pivotally connected adjacent one of its ends to a member 209 mounted on the structure section 201 by means of a pivot pin 207 which passes through spaced apart walls of the member 209 The other end of the link arm 206 is pivotally connected, by means of a pivot pin 208, to a clevis 214 connected to an end of a piston rod 210 of a thrust piston mechanism 211 A bifurcated element 215 is attached to the connecting plate 204 and receives a pivot pin 213 which passes through a ring 216 attached to the cylinder 212 of the thrust piston mechanism 211.

The thrust piston mechanism 211 thus forms another link arm of the mechanism 205 which is pivotably connected via the pivot pin 208 to a frame capping plate 217 As can be seen in Figure 6, the lower surface of 70 the frame capping plate 217 is sloped, whereas the upper surface of the frame capping plate is substantially plane, this plane surface being indicated at 218 On this plane surface 218 there rests a lagging mat 219 in 75 the form of a mesh consisting of a plurality of longitudinal rods 220 and a plurality of transverse rods 221 The longitudinal rods are spot-welded to the transverse rods in the normal way 80 The mat 219 is connected to an adjacent mat 223 by means of fastenings 224 which are shown in an enlarged representation in Figure 7 a and 7 b The fastenings are formed by inter-engaging adjacent end portions 226 85 and 227, of the longitudinal rods of the two mats 223 and 219, respectively.

As can be seen particularly clearly in Figure 7 b, each end portions 227 or 226 ends in an eye 236, the circumference of which is 90 greater than a semicircle As can be seen particularly in Figure 7 b, the terminal section 237 of the longitudinal rod involved adjoining the eyelet curve 238 lies closer to the straight part of the end portion 227 than 95 the curved section 238 of the eyelet curve.

This terminal section 237 runs generally parallel to the straight part of the end portion 227.

On the rear end 235 of the matting the 100 distance between the terminal section 237 and the straight part of the end portion 227 is less than the clear opening D of the eye 239 formed by the end portion 226 at the end 235 of the mat 105 Correspondingly, the gap a of the terminal section 240 of the eye 239 is less than the diameter d of the eye 238.

On the other hand, the distance b between the terminal section 237 and the 110 straight part of the end portion 227 is less than the distance a.

As Figure 7 a shows, the plane of the eye designated 239 forms an angle with the plane of the mating which is substantially 115 the same for all the eyes Conversely, this angle is the opposite of that angle which is formed by the eye 236 with the plane of the matting.

In use, when the mats are being installed 120 the terminal section 237 and the associated end of the longitudinal rod of the matting are inserted in the gap a The terminal section 240 is simultaneously passed through the eye 238 until the position of the parts 125 corresponds approximately to that shown in Figure 7 b Now the thrust piston mechanism 211 is operated so that the piston rod 210 moves out of the cylinder 212 This moves the pivot pin 208 and with it the capping 130 1 594 032 plate 217 along the arc 243 of a circle The upper face of the capping plate 218 moving in the direction of the roof 244, viewed from the structure sections 201 and 202, therefore receives a component of movement parallel to the direction of advancement of the support (i e in the longitudinal direction of the mine roadway or tunnel) as it is moved forwardly and upwardly relative to the frame 203 Accordingly at the end of the arc 243 there is first friction contact of the lagging matting, for example, of the lagging mat 219 with the roof and the upper face 218 of the capping plate 217 due to the increasing pressure against the roof 244.

This causes the lagging mat 219 to be borne along, and a tensioning load is created In this way, the ends 240 and 237 of the mats connected to each other are not pulled out of the eyes 238 and 239 respectively appertaining to them On the contrary, the eyes close and in this way the connection becomes increasingly more secure with the increase in the tension loading Accordingly, the fastenings can no longer be released when the thrust piston mechanism 211 again lowers the capping plate 217 along the arc 243 by the retraction of its piston rod 210, for the installation of a permanent support structure for the mine roadway or tunnel.

Other aspects of a self-advancing roof support as described in relation to Figures la, lb, 2 a, 2 b and 3-5 are described and claimed in the specification of copending

Application No 38696/77 (Serial No 1 594 031).

Claims (7)

WHAT WE CLAIM IS:-

1 A method of lagging the roof of a mine roadway or tunnel, comprising supporting, on roof-supporting members of a self-advancing mine roadway or tunnel roof support having an arched frame spanning across the width of the mine roadway or tunnel, lagging mats which are interconnected to provide a strip of lagging matting in the longitudinal direction of mine roadway or tunnel, each adjacent pair of lagging mats in the longitudinal direction being interengaged in such a manner that tensioning the strip of matting in the longitudinal direction tightens the interengagement between the mats, the roofsupporting members being mounted for movement upwardly or downwardly out of positions providing bracing support of the roof of the mine roadway or tunnel, characterised in that the roof-supporting members are given a component of movement in the longitudinal direction of the mine roadway or tunnel when they are moved upwardlyinto positions to brace the lagging matting against the roof of the mine roadway or tunnel thereby tensioning the matting in the longitudinal direction and tightening the 65 interengagement between adjacent lagging mats in the said longitudinal direction.

2 A method according to claim 1, in which each roof-supporting member is moved along the arc of a circle, having an axis disposed transversely to the said Ion 70 gitudinal direction, as it is moved into its position to provide bracing support of the roof of the mine roadway or tunnel.

3 A self-advancing mine roadway or tunnel roof support, comprising a support 75 unit having an arched frame adapted to span across the width of a mine roadway or tunnel, and at least one actuating mechanism mounted on the frame and carrying one or more roof-supporting members extending 80 forwardly and rearwardly from the frame for supporting lagging matting thereon, the or each actuating mechanism being actuable for moving the or each roof-supporting member carried thereby upwardly towards 85 or downwardly away from a roof of a mine roadway or tunnel positioned above the support, characterised in that the roofsupporting member(s) carried by the or each actuating mechanism is (are) given a 90 component of movement parallel to the direction of advancement of the support on actuation of the actuating mechanism to move the roof-supporting member(s) upwardly towards a roof of a mine roadway 95 or tunnel positioned above the support.

4 A self-advancing roof support according to claim 3, in which the or each actuating mechanism comprises a first pivot arm pivotally connected to the frame about a 100 first axis and carrying one or more of the roof-supporting members, and a second pivot arm, in the form of a vehicle length thrust piston mechanism, pivotally connected adjacent one of its ends to the frame 105 about a second axis and pivotally connected adjacent its other end to the first arm about a third axis, the first, second and third axes being parallel to each other and extending transversely to the direction of advancement 110 of the support.

A self-advancing roof support according to claim 4, in which the first pivot arm is in the form of a pair of parallel elements spaced apart in a direction parallel to the 115 said axes, the second pivot arm moving between said elements on actuation of the actuating mechanism.

6 A self-advancing roof support according to any of claims 3 to 5, in which a pair of 120 support units are provided which are movable relatively to each other by actuating means operable independently of the or 1 594 032 each actuating mechanism for effecting advancement of the support.

7 A method of lagging the roof of a mine roadway or tunnel substantially as herein described with reference to the accompanying drawings.

J Y & Gi W JOHNSON, Furnival House, 14-18 High Holborn, London WC 1 V 6 DE.

Chartered Patent Agents, Agents for the Applicants.

Printed for Her Majesty's Stationery Office by The Tweeddale Press Ltd, Berwick-upon-Tweed, 1981 Published at the Patent Office, 25 Southampton Buildings, London, WC 2 A l AY, from which copies may be obtained.