A.M. Pavlov, D.S. Vasiliev
The development of steeply dipping fine veins is a labour-intensive process. Dilution of mined ore in some cases may reach 80% making the ore grade lower and thus decreasing the profitability of production.
The enhancement of mining efficiency in such geological conditions is an important task, and the proposed solution is described as a case study of the Konevinskoe gold deposit, where steepdipping fine vein-type ore bodies are mined in conditions of the cryolithic zone.
The authors have identified the factors causing quality deterioration of ore (total dilution of 67%) mined by shrinkage method. It has been also found that in case of longwall stoping, alongside with stone sections, the area of low-grade ore (less than 1 g/t) covered by mining accounts for 14.5%. The authors also investigated the fissuring of enclosing rocks and its effect on the rock detachment from stope walls.
Natural stresses have been measured by slot relief method. Mathematical modeling has helped identify the distribution of technology-related stresses in chamber walls and pillars depending on the stope height and mining depth. With due account for the metal distribution pattern and geomechanical state of the rock mass the authors provide the rationale of the effective parameters and order of balance (economically mineable) reserve mining by method of sublevel bench stoping along the strike, as this method has proved to be 35% more efficient than shrinkage method.