Method for controlled fragmentation of hard rock and concrete by the combined use of impact hammers and small load blasts

摘要

The present invention is directed to a method for breaking rock and other hard materials using small-charged blasting techniques followed by a mechanical impact breaker. In small-charge blasting techniques, a gas is released into the bottom of a sealed hole located at a free surface of the hard material. The gas pressure rises rapidly in the hole until the gas pressure causes the hard material to fracture. In one embodiment, the a deeper hole is drilled and/or a small amount of blasting agent is used to cause the formation of a network of subsurface fractures while either not removing any of the rock or removing the rock with very low energy flyrock. In another embodiment, only the central portion of the face is broken and/or removed by blasting. The impact breaker is then used to complete fracturing and removal of the material.