Berm

BERM (EN: bench, berm; DE: Berme; FR: berme; ES: berma; RU: берма) -

1) during the underground development of deposits, the strip, which is adjacent to the contour of the object, which is protected against the influence of the mining works, the outer boundary of which is the starting point for the construction of the protective virgin block (the so-named protective berm). The width of the berm is 5-20 metres, depending on the deposit, and on the category of the object protection. There is also named the berm the auxiliary mine working, which is conducted along the coal layer parallel and simultaneously with the preparatory one, which is having the open contour, which is facing with its open side onto the preparatory working (the so-named narrow berm); it is purposed for the protection of the preparatory working, or for the placement of the equipment; the width is approximately 1 metre.

2) During the open open pit development of deposits, the horizontal or slightly inclined place on the idle edge or on the idle portion of the edge of the open pit, which is separating the benches, which are adjacent according to their height. They distinguish the protective and transport berms. The protective berm serves for the increasing of the stability, and for the decreasing of the general angle of the slope of the edge of the pit, and for the protection of the benches, which are situated below, against the accidental falling of the pieces of rock. The width of the protective berm is 0.1-0.2 of the height of the bench, but not less than the value, which is sufficient for the placement onto the berm of the equipment for the loading and transportation of the fallen pieces of rock.

The transport berm is purposed for the placement of the transport routes, which are connecting the working places of the benches with capital trenches. Its width is determined depending on the type of the transport, on the intensity of the cargo traffic through it, and so on. The transport berm, which is connecting several benches, is named the connective one. The part of the upper place of the bench with the width, which is equal to the base of the prism of the collapse, is named the safety berm; they place the equipment, transport routes, electical power lines outside the limits of the berm of safety.