Roof Bolts In Coal Mines

Low profile roof ranger ii.

Roof bolts in coal mines.

The traditional dead weight loading design. The coal mine roof rating cmrr somewhat quantifies this effect through the strong bed adjustment 9. Take a look at our capabilities and affiliates to learn more. Roof bolting is hard work where miners often have to lift cumbersome pieces of heavy metal into awkward positions.

Position bolting machines and insert drill bits into chucks. Low version of fletcher s rr ii with machine height as low as 25 635m. High roof conditions can present a problem for people who usually work with low profile machines and vice versa. Cable bolting is sometimes used as primary support in coal mines experiencing difficult roof conditions.

Pull down loose rock that cannot be supported. However ground falls still remain a significant factor in underground coal mine injuries and fatalities. Jennmar is the largest manufacturer of roof control products in the u s however we don t stop there. 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.

Roof bolts promised to dramatically reduce the number of. From an engineering standpoint roof bolts are inherently more effective than the wood timbers they replaced. They also drill bolt holes into roofs at specified distances from ribs or adjacent bolts. We can supply the construction mining or tunneling industry with much more.

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. Wide boom swing allows multiple bolt installations from one chassis position. 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.

Short operating length allows bolting the first row of an intersection from one set up. Perhaps the most significant development in coal mine ground control during the last century was the introduction of roof bolting during the late 1940 s and 1950 s.