ROOF BOLTING METHOD

Abstract: This invention discloses the addition of automatic roof bolting equipment (8,11) to continuous mining equipment (3) designed to mine seams of mate­ rial such as trona or coal where it is necessary to place roof bolts to prevent collapse of the roof or overburden above the desired mineral being mined while the continuous miner is advancing into the seam of mineral or coal. The roof bolting apparatus allows the bolting operation to take place while the miner continues mining and is ideally performed by the miner operator.

Description: This invention relates to an automatic roof bolter. Mining seams of minerals such as trona or coal found in rela­ tively deep underground formations has always caused problems of maintain­ ing proper support of the roof structure or overhead rock strata after the mineral or coal has been removed from the seam. Most mining machines have therefore had limited ability to mine to a relatively great depth in a seam without backing out to allow a bolter to be moved into the mined seam to place roof bolts into the overhead seam of rock (or mine roof) to pro­ vide support for the roof against cave-in. This problem has been overcome to some degree by various means such as attaching roof bolters to the mining machine itself and configuring the bolter apparatus such that it hydraulically places and locks into position both floor and roof jacks to prevent vibration and motion of the roof-bolting mechanism during the bolting operation. Various means in the prior art have been utilized to provide such a stable platform for the roof-bolting operation, which consists of drilling the hole in the roof, inserting a bolt with an expansion shell end (similar to a molly bolt) and tightening the bolt into position. This has been achieved using non-automatic and automatic independent bolters. To date only non-automatic bolters have been mounted on mining machines. A non-automatic bolter requires an operator to manually mount a drill, drill a hole, remove the drill, mount a bolt and secure the bolt. An automatic bolting machine automatically conducts the above series of steps sequentially after the machine is actuated. All bolting machines normally have their own motive and power source, independent of any mining machines which they follow. This operation has required great stability, which has been achieved with non-automatic bolters as disclosed in patents such as U.S. Patent No. 3,647,262, to Kemarey, which provides a detachable and movable roof-bolting system. The system is carried by the miner, deploys floor and ceiling jacks to hold the bolter in position, performs the drilling and bolting operation, is recoupled to the mining machine and advanced forward on the mining machine to its original position so as to be in position to detach and perform the next roof bolting sequence. U.S. Patent No. 3,493,058 to J. Zitko, provides a similar system. U.S. Patent No. 4,173,373 to Campbell et al. provides a means for carrying non-auto­ matic bolters on an extensible conveyor, which gives and takes slack between the continuous miner and the roof bolters when they are fixed in position during the bolting operation. U.S. Patent No. 4,199,193 to Damron et al. provides for non-automatic roof bolters to be attached to floor and ceiling jacks which are hydraulically and flexibly attached to the miner. The floor and roof jacks are placed into position with the hydraulically extensible means allowing the miner to continue to move while fixedly holding the roof bolter in a position in which it can be operated. A continuous mining system for extracting minerals, coal, trona or other desired material from an underground seam has been developed which has the capacity, while continuing the mining operation, of conduct­ ing roof bolting operations which can be performed by either the mining machine operator or by a separate bolting machine operator without the necessity of stopping and withdrawing the miner from the minable material face being mined. During the bolting operation, an automatic bolting machine containing a bolt magazine and a drill and bolt driver which can be indexed into position for the required operation of drilling or bolting is electrically or hydraulically moved into pressure contact with the roof of the mined entry at the point where a roof bolt is desired to be emplaced. A drill is then indexed into position and accuated by a power unit. The hole is drilled to the desired depth to accomodate the desired roof bolt. The drill is withdrawn from the hole, indexed away from the drilled hole. A bolt is automatically removed from the bolt magazine and placed in position in the bolter driver which is indexed into position, drives and secures the bolt into the roof. This entire operation is con­ ducted without placing floor support jacks in position to stabilize the bolter. The continuous miner continues to mine the minable material coal face during the bolting operation. Referring to the accompanying illustrative drawings: FIG. 1 is a top plan view of a continuous mining machine embody­ ing the present invention. FIG. 2 is a side elevation of the continuous mining machine emboding the present invention showing the automatic bolter deployed into drilling and bolting position against the mine roof. FIG. 3 is an expanded top plan view of the automatic bolter. FIG. 4 is an expanded side elevation of the automatic bolter in retracted position. It is the primary object of this invention to provide a continu­ ous mining system comprising a continuous mining machine which carries it own fixedly mounted automatic roof-bolting mechanism which can be actuated to contact the mine roof and emplace a roof bolt without the necessity of securing the roof bolter against vibration by the placement of floor jacks, in which the bolting operation can be conducted while the continu­ ous miner is actively mining the minable material face. The drilling and bolting operation can be conducted through hydraulic electronic or mechan­ ically sequenced drilling and bolting steps by either an operator separate from the miner operator or, more preferably, by the continuous miner operator. FIG. 1 illustrates a top view of a conventional type of continu­ ous miner, such as a Joy 12HM9 or 12HM10 (manufactured by Joy Mahinery of Frankin, PA), which has been lenthened to allow the mounting of automatic roof-bolting equipment on the miner. A continuous mining machine is a mining machine designed to remove minable material from the minable material face and to load the material into cars or converyors without the use of cutting machines, drills or explosives. It is preferred to locate the automatic bolting equipment as far forward on the miner as possible to allow roof bolting as early as possible to prevent cave-ins. It is thus particularly desirable to mount the automatic bolting equipment ahead of the operator or operators on the machine where safety regulations require. The automatic bolting equipment may, if desired, be mounted at any desired space on the miner. Depending on the size, length and width of the machine, one or more automatic bolting machines are mounted on the contin­ uous miner. The frequency and spacing of bolts is determined by safety requirements. The automatic bolting machine mechanism 1 is fixedly mounted to the chassis of a continuous mining machine 2, which contains cutter heads 3 driven by driver mechanism 13 and a mined material discharge conveyor 4 and an adjustable conveyor tail piece 14. The automatic bolting mechanism 1 is mounted to an extensible mechanism 5 by which the automatic bolting mechanism 1 is moved vertically until an anchor stud 12 comes into pres­ sure contact with the mine roof 6. The automatic bolting sequence is then initiated in which a drilling mechanism 7 is indexed onto position 14 and actuated to drill a hole 20 in the mine roof 6. The drilling mechanism 7 is then withdrawn and indexed back to its original position. A bolt is automatically removed from a bolt magazine 8 and is indexed into the bolt driver 9, the driver 9 is indexed into position 14, the bolt is pushed up into the drilled hole and tightened to lock it into position. Any auto­ matic bolting system may be used, such as Tamrock Robolt built by Tampella-Tamrock of Finland. These automatic bolters are well known in the industry but have previously only been attached to boom arms extending from the bolting mechanism's own motive and power source separate from a mining machine. The automatic bolter 1 is raised by extensible mechanism 5 which can be driven by conventional means such as hydraulic or electric motors. The drilling mechanism 7 and the bolt driver 9 can also be driven by hydraulic or electric motors. The cutter heads on the continuous miner are conventional heads such as drum, fixed and ossillating heads and contact the mine face 19 to remove minable material. Depending on the type of continuous miner used, the miner may carry a stabilization jack 15 to stabilize the miner during mining opera­ tions. The miner controls 16 and the automatic bolter controls 17 are shown in FIG. 1 where the miner operator can operate both the miner and the automatic bolter. An alternate embodiment would place the automatic bolter controls in area 18 to be operated by an operator other than the miner operator.

Claims: 1. A method of continuously mining underground minable material with a continuous mining machine comprising mining the minable material from a seam of said minable material to form a mined cavity having a roof and floor in which the roof is stabilized by roof bolts secured in holes drilled into the roof, characterised in that it comprises fixedly attaching to the mining machine at least one automatic roof bolting machine which can be actuated by the operator to secure the roof by emplacing roof bolts in the absence of floor and roof stabilizing jacks for the automatic roof bolting machine as the machine continuously mines the minable material from the seam face. 2. A method as claimed in claim 1 wherein the automatic roof bolting machine is hydraulically actuated by the mining machine operator. 3. A method as claimed in claim 1 or claim 2 wherein the minable material is trona. 4. A method as claimed in any of claims 1 to 3 wherein there are two automatic roof bolting machines mounted forward of the operator of the mining machine. 5. A method as claimed in claim 4 wherein the automatic roof bolting machines are operated by an operator other than the mining machine operator.

Inventors: KENISON, BOB ANDREW
Applicants: RHONE-POULENC BASIC CHEMICALS CO.
Application year: 1986
Main classification: E21D20
IPC codes: E21D20, E21C41