WELL STEMMING METHOD Russian patent published in 2011 - IPC F42D1/08 

FIELD: mining.

SUBSTANCE: during implementation of the method a stem the cross dimension of which is smaller than well diameter is lowered into well by means of stem lowering mechanisms attached to the stem. First, expansion is made in well at distance of 1-2.5 m from day surface; then, stem with stem lowering mechanisms fixed on one of its sides is lowered into well and its edges are located perpendicular to well wall till it reaches the expansion into which the stem ends are led.

EFFECT: increasing blast efficiency, reliability if stem installation, and reducing the cost of blasting operations.

4 dwg