THE METHOD OF HORIZONTAL AND SLIGHTLY INCLINED UNDERGROUND WORKINGS DRIVING USING COMPENSATION BLAST-HOLES AND BORE-HOLES
The paper shows that when driving of workings in any cross-section of IIIa-IV categories fortress rocks compensation blast-holes and bore-holes are not advisable to apply but to use a wedge cut. However, it is not effective for the species of stronger categories I-III in terms of working drilling run after the explosion, and blast hole efficiency ratio (BHER).When the depth of drilling holes of 1.5-1.6 m face drilling run is 1.3-1.35 m according to rocks fortress up to 10 units on a scale of Professor M.M. Protodyakozhnov BHER doesn't reach 0,85-0,9. When driving of workings of III category fortress cross-section 5-11 m<sup>2</sup> hand punches on air leg attachment or portable drill rigs it is efficient to drill cuffing and auxiliary holes of 36-41 mm in diameter and one relief hole of 65 mm in diameter are drilled in one step with combined bit on expanding cone wherein part formed integrally with the skewer it anticipatory bit of smaller diameter. In this case, the BHER is increased to 0.95, and face drilling run increases to 1.4-1.5 m. This illustrates the effectiveness of the compensation blast hole.