Mining Research Corporation, Inc, under contract with Snow Ice and Permafrost Research Establishment Corps of Engineers, U. S. Army, conducted explosion tests in frozen Keweenaw silt, to determine: (1) the most efficient type of explosive for blasts in frozen ground, (2) the fundamental relation between weight of explosive and depth of charge, (3) the proper position of the charge relative to the frozen-ground interface, (4) the feasibility of fracturing the frozen layer by placing a charge in the underlying unfrozen material, and (5) the effect of the diameter of the borehole and of the shape of the charge upon the results of blasting.
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