The problem of resource saving when mining diamond-bearing kimberlites at the Udacha open pit of ZAO Udachinsky GOK is extremely relevant, since in the last decade there has been a stable tendency of reducing the quality of commercial products - diamond crystalline raw materials. Examination of the character of damages of diamond monocrystals suggests that the technological defects of crystals are caused, first of all, by the pulse mode of loading crystals of host rocks at the stages of explosive destruction, mechanical crushing and grinding of kimberlite ore at the crushing and milling equipment. This is evidenced by the nature of damage to diamond single crystals manifested in crushing, shear and chipping cracks. The highest damageability occurs in medium and large diamonds, especially of the +2 class. In its turn, according to the CCA, taking into account the cost of diamonds of different size and quality groups, 1% increase in preservation allows to get an additional profit of about $7 million. ALROSA's efforts are aimed at improving the natural preservation of rough diamonds, which is why research has been resumed to predict the parameters of stress waves that are potentially dangerous in terms of damage to the rough diamonds. Since kimberlites are breccia and tuff-like rocks with rather homogeneous properties in layers with different elevations, which tend to increase acoustic stiffness with depth of occurrence, they can be considered as layered homogeneous isotropic elastic media.
Explosive blasting of dry granite massifs in the quarries of the Leningrad region is currently carried out with standard explosives: ammonite and grammonite 79/21 (82/18). Explosive blasting of watered massifs is carried out with 30/70 and 50/50 grammonite, granulotole and conercial explosives of granipor type. The experience of our foreign northern neighbors has shown that under similar conditions safer and cheaper ANFO-type non-trinitrotoluene compositions and other water-emulsion explosives can be successfully used. Switching to these explosives allows to refuse the expensive transportation of dangerous cargoes over long distances, as they can be prepared on site. The first experience of application of locally prepared no-trinitrotoluene explosives has been carried out at several granite pits of Vyborgsky District of the Leningrad Region and Kamennogorsk. As the simplest explosive the granulite-Zh developed by the authors was used (patent No.2088559 with the priority of invention of 1992). Granulite-G is an explosive composition with the averaged chemical formula C 4.0-5.0 H 8.0-9.0 N 0.04-0.08 O with the following proportions of components by weight, %: ammonium nitrate - 80-95; fatty protein additive - 5-20.
Крупные массовые взрывы и интенсификация отбойки горных пород на действующих карьерах, расположенных вблизи зданий и инженерных сооружений, обуславливают необходимость прогнозирования действия ударных воздушных волн (УВВ), так как они могут, представлять определенную опасность ...
