METHOD OF DRIVING OF VERTICAL MINE SHAFTS IN FLOODED UNSTABLE ROCKS Russian patent published in 2015 - IPC E21D1/00 

FIELD: mining.

SUBSTANCE: method includes the formation of ice wall around a shaft outline. Execution of drilling-and-blasting works by drilling the breaking and main blastholes with their subsequent loading by explosive charges and blast firing. Monitoring of stresses in freezing columns in the zones of contact of two rocks with differing physico-mechanical properties. At achievement of maximum allowable values of tension in freezing columns in zones of contact of two rocks with differing physico-mechanical properties in a face between the last row of breaking blastholes and the shaft outline trunk contour two rows of compensation non-charged blastholes are drilled which form pre-outline and outline row of blastholes and located chequerwise with reference to each other. These rows are located at the pre-set distances from the main blastholes and the shaft contour. The centre of each compensation blasthole of the pre-outline row is located between the neighbouring blastholes and at the same distance from them.

EFFECT: decrease of power losses during drilling-and-blasting works inside a shaft contour that allows to increase the speed of its driving.

3 cl, 2 dwg