PURPOSE:  To identify and model sources of methane emissions on longwall faces and continuous miner sections so that the effectiveness of methane control technology can be improved while reducing the explosion hazard experienced by underground miners.

RESEARCH SUMMARY:  The inability to predict and control methane emissions represents a significant risk for underground coal mine workers. Recent methane explosions include the July 2000 event at the Willow Creek Mine in Utah (2 fatalities and 8 injuries), the September 2001 event at Jim Walter Resources No.5 Mine in Alabama (13 fatalities and 3 injuries), and in January 2003 at the McElroy Mine in West Virginia (3 fatalities and 3 injuries). A frictional ignition in the gob of the Willow Creek Mine in Utah in November, 1998 is considered the most likely source of a fire which required the sealing of the mine. Other underground explosions have occurred at the Pinnacle Mine in West Virginia in 2003 and the frictional ignition and subsequent fire at the Buchanan No. 1 Mine in Virginia in 2005. In January 2006, a methane explosion at the Sago Mine in West Virginia resulted in 12 fatalities and 1 injury. The Darby No. 1 Mine explosion in Kentucky in May 2006 led to 5 miners losing their lives.

As part of the proposed research effort, the effectiveness of methane drainage on longwall and room and pillar face emission rates is assessed through underground methane emissions monitoring, borehole production evaluations and methane content measurements. Analytical, non-site specific algorithms are produced to predict face methane emission rates. Methane prediction methodologies are packaged for technology transfer to industry. Methane drainage practices for continuous miner room and pillar operations are reviewed to evaluate potential application to abandoned or sealed workings. Finally, the project identifies frictional ignition tendencies in coal measure rock from historical frictional ignition sites. A conceptual incendivity index for coal measure rocks compares the incendive tendencies of differing rock compositions.

A surface borehole monitoring experiment began under the current project and is in progress on a Pennsylvania longwall panel. The adaptation of commercially available reservoir modeling software has successfully simulated gas flows for various borehole configurations and longwall mining scenarios. Two empirical methods for predicting longwall face emissions for increased face lengths have been developed and published.