Calculation of the overburden ratio by the method of financial and mathematical averaged costs

Abstract

Purpose. To calculate the parameters of the development of brown coal deposits, including the limiting overburden ratio, when involving coal clay into the development together with brown coal in the composition of the coal mass. Methodology. To calculate the cost of mining a mineral, the method of financial and mathematical averaged costs was applied, considering the level of projected capital investments and the cost of investment funds. Findings. The influence of the involvement of coal clays in the development together with brown coal as a part of coal mass on the limiting overburden ratio is investigated. It is determined that the limiting overburden ratio for a mining enterprise that extracts brown coal is 20 m3/t, and for the extraction of coal clay in a mixture with raw brown coal 17 m3/t. The parameters of brown coal production in Novo-Dmytrivske deposit have been established, which have shown that with a coal production of 9 million tons/year, the overburden ratio is 4 m3/t. In the case of extraction of associated minerals in the form of coal clays, the opencast capacity can increase up to 20 million tons/year, and the overburden ratio will decrease down to 1 m3/t. Originality. The dynamics of the change in the current overburden ratio over the years for the extraction of coal mass with the share of coal clays from 0 to 50% for the conditions of Novo-Dmytrivske brown coal deposit has been established. The costs to produce raw coal have been determined in terms of both natural and conventional fuel. The modelling of the costs for the extraction of minerals and rock mass, depending on the overburden ratio, has been carried out. The change in the overburden ratio was determined when coal clay and off-quality brown coal were involved in the production in comparison with the production of raw brown coal. Practical value. It has been established that those deposits and areas that were previously related to the development of the mine method or open-pit mines with large losses of coal during the complex mining of conditional seams of raw brown coal, off-quality seams, and coal clays, can potentially be mined with minimal losses of useful fossil and with low cost.