METHOD FOR FORMATION OF AIR GAPS BY ELEMENTS OF FOAM POLYSTYRENE Russian patent published in 2008 - IPC F42D1/08 

FIELD: drilling and blasting operations, applicable in various branches using blasting operations in hard rock masses.

SUBSTANCE: the method consists in separation of the explosive charge into parts by an air gap of foam polystyrene. In boreholes without any distortions and inrushes of the walls the air gaps are formed by sinking of an element of foam polystyrene in the form of a square-section parallelepiped with the longer side equal to 0.65 to 0.71 of the borehole diameter into the borehole. In boreholes with distortions and inrushes-elements of a foam polystyrene in the form of a short square-section parallelepiped with the longer side equal to 0.65 to 0.71 of the borehole diameter and the size of the section within 0.35 to 0.43 of the borehole diameter, and in boreholes with distortions but without any inrushes of the walls - of the preset quantity of blocks of foam polystyrene with a length of the face equal to 0.45 to 0.52 of the borehole diameter, a thickening amount of explosive placed in a soft or elastic envelope with a diameter exceeding the borehole diameter is placed on the elements.

EFFECT: simplified formation of the air gap of foam polystyrene in an explosive charge.

3 dwg