The Direct Method of Determining Coalbed Gas Content in the Mine (Draft for Comments)

This document applies to coal mines, testing institutions and relevant equipment users conducting direct underground determination of coalbed gas content by the degassing method, atmospheric-pressure desorption method or underground one-stop method. It specifies requirements for fixed-point sampling, sample canning, instruments and leak-tightness testing, temperature and pressure correction, and calculation of lost and residual gas content, as well as requirements for test reports and record retention. Original gas content shall not be sampled in drainage areas, pressure-relief zones, fire areas or waterlogged areas, and at least two samples shall be taken at each measuring point. The revised draft adds general requirements and an underground one-stop method, improves crushing-desorption procedures and calculations of desorbable gas content and dry ash-free gas content, and revises criteria for qualified, reference and rejected samples.