________________ type of drill consists of a long Steel bit which is mechanically lifted up and dropped down to disinteg…

__________________ types of equipment have a continuous flow of work turned out.

_______________ are used to change the direction of ropes and to raise greater loads with less efforts.

_____________________ bits are used when some rocks are so abrasive that steel bits have to be replaced after they have …

________________ is an air operated drill which can easily be carried from one place to the other.

The annual cost of ___________ may be determined independently or it may be linked up with the depreciated cost of the e…

In _________ method, the depreciation of properties assumed to be equal to the annual sinking fund plus the interest on …

____________________ conveyors operate in series with end discharge transfer points.