ESTIMATION OF LEDGES’ STABILITY IN OPEN PITS DEVELOPING DIAMONDS DEPOSITS OF YAKUTIA (ON EXAMPLE OF CAREERS "YUBILEYNY" AND "ZARNITSA")

Abstract

The predominance of subvertical and subhorizontal disjunctive dislocations in the enclosing rocks of the kimberlites in Yakutia excludes the manifestation of typical deformations of the ledges slopes (wedge, flat etc.), as exemplified in the "Zarnitsa" and "Yubileyny" quarries. The deformation of the ledges slopes consists chiefly in the crumble of rocks because of their cryogenic weathering. Collapsing of the ledge by overturning elementary rock blocks is possible, if there are long cracks that are subparallel to the slope plane and fall into the rock massif.
Deformations with a complex geometry of their boundaries and a deepening into the rock massif, which form the overhangs of rocks overhanging over the ledge are formed over the heavily watered areas of subhorizontal cracks in the slope. It is necessary to monitor deformations by periodic laser scanning with the estimation of the rate of deformations growth in order to predict the further development of established deformation