Methane drainage from roof strata using an overlying drainage gallery

Abstract Methane drainage is conducted in Polish coal mines to reduce mine methane emissions and to keep methane concentrations in mines within safety limits. This article describes a method of methane drainage conducted during mining in Polish coal mines. The method is based on driving a drainage gallery into a coal seam situated above or below the worked seam prior to its extraction by a longwall method. This article shows the influence of a typical ventilation system on the drainage efficiency at longwall panel B-11 in seam 348 with an overlying drainage gallery. At this longwall, measurements of the methane emissions and efficiency of the methane capture were conducted. These measurements consisted of gauging the methane concentration, air velocity, absolute air pressure and the amount of methane captured by the drainage system. The experimental data were used to estimate the variations in the total methane release, methane release into the ventilation system and – most importantly – the efficiency of methane drainage. The results obtained were analysed statistically, and the influence of different factors on the total methane release and the amount of methane captured into the drainage system were determined.

[1]  Nikodem Szlązak,et al.  Impact of coal output concentration on methane emission to longwall faces / Wpływ koncentracji wydobycia na wydzielanie metanu do wyrobisk ścianowych , 2012 .

[2]  C. Özgen Karacan,et al.  Degasification system selection for US longwall mines using an expert classification system , 2009, Comput. Geosci..

[3]  K. N. Trubetskoy,et al.  Characteristics of methane release in highly productive coal mines , 2011 .

[4]  Gerrit V.R. Goodman,et al.  Hydraulic conductivity changes and influencing factors in longwall overburden determined by slug tests in gob gas ventholes , 2009 .

[5]  F. S. Kendorski,et al.  Strata disturbance prediction for mining beneath surface water and waste impoundments : Proc 1st conference on ground control in mining, Morgantown, 27–29 July 1981, P76–89. Publ Morgantown: West Virginia University, 1981 , 1983 .

[6]  W. P. Diamond.  Methane control for underground coal mines , 1994 .

[7]  C. Özgen Karacan,et al.  Coal mine methane: A review of capture and utilization practices with benefits to mining safety and to greenhouse gas reduction , 2011 .

[8]  Leszek W Lunarzewski,et al.  Gas emission prediction and recovery in underground coal mines , 1998 .

[9]  N. Aziz,et al.  Developments in coal mine methane drainage and utilisation in Australia , 2009 .

[10]  C. Özgen Karacan,et al.  Modeling and prediction of ventilation methane emissions of U.S. longwall mines using supervised artificial neural networks , 2008 .

[11]  C. Karacan,et al.  An analysis of reservoir conditions and responses in longwall panel overburden during mining and its effect on gob gas well performance , 2012 .

[12]  Aziz Naj,et al.  Evolution and application of in-seam drilling for gas drainage , 2013 .

[13]  D. N. Whittles,et al.  The stability of methane capture boreholes around a long wall coal panel , 2007 .

[15]  Geoff Wang,et al.  A gas mixture enhanced coalbed methane recovery technology applied to underground coal mines , 2013, Journal of Mining Science.

[16]  Ricardo A. Olea,et al.  Inference of strata separation and gas emission paths in longwall overburden using continuous wavelet transform of well logs and geostatistical simulation , 2014 .

[17]  W. P. Diamond,et al.  Evaluation of alternative placement of longwall gob gas ventholes for optimum performance , 1994 .

[18]  V. Palchik,et al.  Formation of fractured zones in overburden due to longwall mining , 2003 .

[19]  Junhua Xue,et al.  Mining-induced strata stress changes, fractures and gas flow dynamics in multi-seam longwall mining , 2012 .

[20]  V. Palchik,et al.  Localization of mining-induced horizontal fractures along rock layer interfaces in overburden: field measurements and prediction , 2005 .

[21]  Eugeniusz Krause,et al.  Prediction of methane emissions during the extraction of close-to-roof layer of a seam of large thickness , 2012 .

[22]  D. P. Creedy,et al.  Gas control in underground coal mining , 1997 .

[23]  G. S. Esterhuizen,et al.  Reservoir simulation-based modeling for characterizing longwall methane emissions and gob gas venthole production , 2007 .

[24]  Klaus Noack,et al.  Control of gas emissions in underground coal mines , 1998 .