NEW APPROACHES TO THE IMPLEMENTATION OF THE MINING TECHNOLOGY OF DIMENSION STONE USING A CLOSE-SET DRILLING

The analysis of the current state the non-blasting monolith extraction technology was conducted. The further research direction was substantiated. Has been considered and justified the rational parameters of close-set drilling technology of dimension stones. Solution is offered that consist the combined drilling (a close-set and a holes line drilling), that provides to increase of stone splitting efficiency under its own weight. The calculation of the parameters of the scheme of partial underdrilling at a monolith of stone with the purpose of reducing the volume of drilling works is given. Diagrams of tensile stress changes depending on the specific area of splitting were built. A rational correlation between the drilling parameters of the holes has been established by solving the problems of loading the cantilever beam and stress concentration by the Kirsch solution. The most important parameter for the implementation of this technology is the ratio of monoloth hight to its length. Engineering formulas are proposed for calculating the technological parameters of the realization of the “gravitational-hole” stone splitting. The configuration of a rough block of stones is determined under which this technology can be realized. Creating of close-set holes provides the increase of maximal tensile stress with equal values of specific splitting area ratio. It is established that the effective drilling depth of close-set holes is 43,2 % of monolith height. It is estimated that combined drilling method application of savings from drilling operation will be 11,36 %.