Roof Bolts For Use In Mines

In many mines a stronger unit that is largely self supporting overlies a weak immediate roof layer figure 1b.

Roof bolts for use in mines.

We can supply the construction mining or tunneling industry with much more. Several longwall mines are using the tenax tencate polymer mesh roof support system. 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. 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.

Jennmar is the largest manufacturer of roof control products in the u s however we don t stop there. Dsi has one of the strongest nuts on the market. Experience has shown that roof bolts are extremely efficient in the suspension mode 6 7 8 though. In these circumstances roof bolts act to suspend the weaker layer.

Secondary function of roof bolts in weaker ground. 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 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. Cable bolting is sometimes used as primary support in coal mines experiencing difficult roof conditions.

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. The composite bolt is particularly interesting not only because of its high tensile strength which is double or triple the strength of the steel but it is also non sparking oler said. Take a look at our capabilities and affiliates to learn more.