Coal production costs components and coal price as crucial factors in the designation of coal output

Due to diverse geological and mining conditions of specific longwalls, amortization of mining machinery, as well as costs structure in different coal mines, daily coal output should be designated for each longwall face separately. In view of definite reserves of a given longwall panel, daily coal output determines its extraction time, thus, the analysis should also consider the time factor. Unlike popular cost allocation methods in accordance with the criteria of the relations between costs and changes in coal output, the proposed method is based on a different approach to a longwlall face, including the analysis of the costs of the preparatory works stage previous to extraction works. The inclusion of the time factor has led to the derivation of three costs categories: absolutely fixed costs KBS relatively fixed costs KWS, variable costs Kz. On the grounds of the above mentioned three costs categories an economic model was designed, enabling the designation of daily coal output depending on the reserves of a given longwall panel and its extraction time, for the assumed profit level, or for the assumed balance between the costs of coal production and the incomes from coal sales. The model incorporates the total costs of coal production, including all stages of the production process: preparation works of the longwall panel, longwall moves extraction works, longwall shut down. The grounds for the model, in accordance with the assumed methodology, were provided byeconomi modelling used in diagnosing critical functional zones of longwall faces or coalmines.