Enhancing Efficiency of Overburden Removal and Coal Mining at Elginsky Coal Deposit in Yakutia by their Softening with Surfactants

The paper analyzes the impact of physical and mechanical properties of different lithological rock types at the Elginsky deposit on the performance of the KSM-2000R Continuous Surface Miner. It has been established that the productivity of KSM-2000R stands at 1400 m3/h if the compressive strength of the rocks is not exceeding 40 MPa, which covers coals and carbonaceous siltstones. However, if the share of hard particles with the compressive strength between 40 and 60 MPa rises to 40% (aleurolites mainly), the productivity is expected to be reduced down to 1000 m3/h, while with the 33% of the components with the compressive strength between 60 and 80 MPa it will further drop down to 650 m3/h. As the rock strength goes up, the productivity of the Continuous Surface Miner can drop dramatically, especially during the winter period. A considerable increase in the digging resistance of frozen rocks and coals requires their softening to enable blast-free mining. Treatment of rocks with surfactants can be one of the solutions to this problem. It is suggested to use a surfactant, i.e. NaCl solution, to soften the rocks. After these rocks were treated with surfactants at negative temperatures down to –20 °C, the compressive strength decreased by 30-50% while the tensile strength was reduced by about 50% for all the rocks. As the research results show, the use of surfactants can reduce the strength of frozen rocks and thereby ensure their blast-free mining using the Continuous Surface Miners.