Roof Bolts In Coal Mines

Experience has shown that roof bolts are extremely efficient in the suspension mode 6 7 8 though suspension becomes more difficult if the weak layer is more than 3 ft thick.

Roof bolts in coal mines.

High roof conditions can present a problem for people who usually work with low profile machines and vice versa. Roof bolting is hard work where miners often have to lift cumbersome pieces of heavy metal into awkward positions. Pull down loose rock that cannot be supported. Independent front and rear lift for easy tramming on uneven bottom.

When conditions change and the miners are out of their element safety can become a concern. Since the introduction of roof bolts in the coal mines during the late 1940s and 1950s roof bolts promised to dramatically reduce roof fall accidents. Position bolting machines and insert drill bits into chucks. They also drill bolt holes into roofs at specified distances from ribs or adjacent bolts.

Take a look at our capabilities and affiliates to learn more. We can supply the construction mining or tunneling industry with much more. Jennmar is the largest manufacturer of roof control products in the u s however we don t stop there. Low profile roof ranger ii.

The coal mine roof rating cmrr somewhat quantifies this effect through the strong bed adjustment 9. However ground falls still remain a significant factor in underground coal mine injuries and fatalities. 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. Low version of fletcher s rr ii with machine height as low as 25 635m.

Wide boom swing allows multiple bolt installations from one chassis position. Cable bolting is sometimes used as primary support in coal mines experiencing difficult roof conditions. Short operating length allows bolting the first row of an intersection from one set up. The traditional dead weight loading design.

From an engineering standpoint roof bolts are inherently more effective than the wood timbers they replaced. Roof bolts promised to dramatically reduce the number of.