Determining the Source of Longwall Gob Gas: Lower Kittanning Coalbed Cambria County, Pennsylvania.

摘要

The report presents results of a cooperative research project between the U.S. Bureau of Mines and Beth Energy Mines, Inc. Four coreholes (two before mining and two after mining) were drilled at a longwall mine operating in the Lower Kittanning Coalbed to obtain coal and rock samples from overlying strata to determine their gas content at various times in the mining cycle. The results of those tests indicate that 91 percent of the gas removed from the overlying strata came from coalbeds. The analysis indicates that only 40 percent of the total gas produced from the panel actually came from the strata directly overlying the panel. The remaining volume of gas production probably migrated to the longwall gob from overlying, and perhaps underlying, strata immediately adjacent to the panel.