The derivation and application on the caloric regression equation of commercial coal in mining area;

Discussion on some problems during application of national standard sampling for commercial coal;

Experience of dealing with quality dispute about commercial coal;

This paper expounds the concept of merchantable coal sampling and the connotations of sampling precision, analyzes some factors influencing the sampling precision, and puts forward some measures for improving sampling precision of merchantable coal.

Deferent processes are designed for different impurities,so that the impurities inside the coal-flow can be removed effectively and the quality of commercial coal is improved to meet the market demands.