Piping Methane in Underground Coal Mines

摘要

A growing number of coal mine operators are developing plans for degasifying coalbeds within active mines and for piping the methane through underground passageways to the surface. This interest flows from the safety and cost benefits that might accrue by reduced quantities of methane being liberated in the mine atmosphere during mining; interest has been furthered by the demands to utilize fully all energy resources of our nation. Methane piped through mine passageways in quantities and concentrations sufficient to contaminate large areas of the mine justifies caution and concern in the design of the system, its installation, protection, and maintenance. Pipeline leaks and ruptures are not uncommon; a pipeline, for example, in a northern West Virginia mine was destroyed by electrolytic corrosion within 1 year. Fires and explosions involving compressors have had serious ramifications. Thus, it is important that the safety features needed in underground degasification systems be considered carefully. Toward that end, a task force of the Mining Enforcement and Safety Administration (MESA) (now called the Mine Safety and Health Administration, MSHA) studied the experiences of the natural gas industry and of European coal miners pertinent to pipeline construction and safety. The results of that study are discussed in this report. The reader is cautioned that many of the findings may not necessarily be applicable to conditions in a specific mine and that some recommendations were projections beyond the present state-of-the-art. The task force concluded that methane transport through pipelines in underground passageways could be safe where the installations are subjected to continuous evaluation by all concerned and where the installations are designed, installed, and maintained by knowledgeable and competent persons. (ERA citation 08:045504)