We have applied the long hole blasting to the mining method for low grade pyrite ore body. And we have succeeded in the application of block caving method to breaking pyrite ore body which was difficult to mine according to caving, collapse and underground water.
The plan of long hole blasting is based upon a linear charge originated in short diameter long holes against the theory of a concentrated charge, therefore we have arranged the line of least resistance and spacing of holes adaptable for a linear charge without cushioning.
At the plan of blasting of block caving method, perfect-fanshaped arrangement of holes by symmetrical drilling chambers was suitable for weak and brittle conditions of ore body from our results.
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