METHOD FOR NON-WORKING PIT WALL FORMING Russian patent published in 2005 - IPC

FIELD: mining industry, particularly to built non-working pit wall in permafrost ground.

SUBSTANCE: method involves loosening rock, constructing trap trench along haulage berm under the berm and forming protective rock bank. Trap trench is of triangular shape and one side thereof arranged opposite to main slope of non-working pit wall has inclination angle of not less than 36° and not more than 40°. Horizontal adjustable rebound area panel is left in area extending from lower ledge edge to trap trench contour. Rock loosening within area defined by excavation contours of working ledge and trap trench is performed by simultaneous blasting out blast-holes and trench-forming holes of the first and the second rows. Holes of the first and the second rows are drilled in working ledge and have subdrilling depth equal to trap trench depth and to one-half thereof correspondingly. Distance between the rows is determined from the given relation.

EFFECT: reduced volume of works for trap trench forming.

1 ex, 4 tbl, 5 dwg