advantages and disadvantages of manual labour

The mining regulations do not stipulate definite bench heights in hard rocks except that the bench width has to be more than the bench height. The height of coal bench, i.e., the coal face, should not exceed 3 metres.īenches in sand stone and hard rocks are rarely vertical but generally sloping at a small angle with the vertical. During the rainy season, there is possibility of land slide of the loose debris and it is desirable to keep the width of the floor much larger than the height of the bench. which is likely to slide the bench height should not exceed 1.5 m. The width of the floor should not be less than the height of the face (high wall) and the heights of benches are as follows:

A bench has two elements, the floor and the face (high wall). The overburden and mineral deposit can be extracted by formation of benches or by keeping the surface sloped so that the angle of slope does not exceed 45° from the horizontal. The maximum depth from the surface in existing mines in our country is 120 m but future mines are planned to reach a depth of nearly 480 m.

The wages of labour, the selling price of mineral and the margin of profit and the major considerations in deciding the limiting ratio which is as follows in coal mines:

Advantages and disadvantages of manual labour