Roof Bolts For Use In Mines

The nut is offset with respect to the longitudinal axis of the shaft of the bolt so that when the bolt is rotated by means of the nut the bolt is caused to describe a.

Roof bolts for use in mines.

The invention comprises a roof bolt and nut in screw threaded engagement said bolt comprising a shaft for insertion in a hole drilled in a mine roof and a threaded portion engaged by the nut whereby the bolt may be rotated. A roof bolt comprises a shaft for insertion in a hole drilled in a mine roof and a head whereby the bolt may be rotated the head being offset with respect to the longitudinal axis of the shaft so that when the bolt is rotated by means of its head the shaft is caused to describe a circle of greater diameter than its own diameter and where the offset is at least 08 inch and not more than 0 25. Experience has shown that roof bolts are extremely efficient in the suspension mode 6 7 8 though. We can supply the construction mining or tunneling industry with much more.

A roof bolt comprises a shaft for insertion in a hole drilled in a mine roof and a head whereby the bolt may be rotated the head being offset with respect to the longitudinal axis of the shaft so that when the bolt is rotated by means of its head the shaft is caused to describe a circle of greater diameter than its own diameter and where the offset is at least 0 08 inch and not more than 0 25 inch. In the design and construction of mining roof bolts support support forms and parameters are selected based on experience or engineering analogy so there are some problems such as difficult roadway maintenance low coal production rate and tight mining replacement. In many mines a stronger unit that is largely self supporting overlies a weak immediate roof layer figure 1b. Several longwall mines are using the tenax tencate polymer mesh roof support system.

The jm cable fully grouted cable bolt is proven to be a very versatile roof support due to its ability to control many different ground conditions from increasing the lifespan of standard cable bolt supports in long term main entry systems to stopping the ingress of water. In low seam mines the flexibility of the cable bolts allows greater length supports to be installed near the advancing face without the use of couplers. Dsi has one of the strongest nuts on the market. Cable bolting is sometimes used as primary support in coal mines experiencing difficult roof conditions.

Roof bolts in helping to create a stable rock structure are the first line of defence to protect mineworkers from fall of ground related hazards which highlights the importance of correct roof. In these circumstances roof bolts act to suspend the weaker layer. Jennmar is the largest manufacturer of roof control products in the u s however we don t stop there.