METHOD FOR HIGH LEDGE CUTTING IN CONFINED ENVIRONMENT Russian patent published in 2008 - IPC E21C41/26 F42D5/05 

FIELD: mining, particularly excavation of hard rock in confined environment demanding prevention of blasted rock cuttings falling under high ledge slopes, namely during re-activation of temporarily unworked edges of deep pits, spacing sides of deep rock excavations in road building and so on.

SUBSTANCE: method involves separating high ledge into layers so that each layer has height not exceeding excavation equipment digging height; preparing the layers for following blasting by arranging light-weight woven mat with weight on side slope of high ledge below layer to be blasted; drilling blast-holes in each layer; filling blast-holes with charges, wherein blast-holes, which are outermost from side slope, are filled with decreased charge; arranging two-layer gas-permeable covering on all opened surfaces of area to be blasted, wherein lower end of the covering is made of metal mesh, upper one is created of mats formed of worn-out car tires; inserting lower covering part under mat for distance of not less than tire diameter; blasting rock; removing covering and excavating cut rock.

EFFECT: prevention of rock fragment dispersion under high ledge slopes during blasting works performing and rock excavation.

2 dwg