Home Contact Us home contact search

Pre-feasibility Study for Coal Mine Methane Recovery and Utilization at Mopanshan Mine, Guizhou Province, China

Pre-feasibility Study for Coal Mine Methane Recovery and Utilization at Mopanshan Mine, Guizhou Province, China

With funding from the United States Environmental Protection Agency (USEPA), under the auspices of the Global Methane Initiative (GMI), this pre-feasibility study evaluates the utilization of coalmine methane (CMM) produced from a proposed degasification system comprising pre-mine drainage and gob wells, for use as fuel to generate electricity for the Mopanshan Coal Mine in Guizhou Province, China.

Presently, there are no mining activities occurring at Mopanshan Coal Mine (Mopanshan), but mine planning and development are underway.  In October of 2005, the Guizhou Qianxi Energy Development Co. Ltd. (GQEDC) obtained the exploration rights to conduct the coal resource assessment at Mopanshan.  The “Coal Exploration and Geological Report” conducted by the Shandong Coal Geological Engineering Investigation Institute (SCGEII) provided the basis for the geologic review presented herein, as well as the coal exploration and resource data.  An additional study, “Mopanshan Mine Feasibility Report,” completed in November of 2013 by the Nanjing Design Institute of Coal Science and Industrial Group (NDICSIG), assessed the feasibility to site a coal mine in the Mopanshan coalfield and laid out a preliminary mine plan.  With the completion of NDISCSIG’s feasibility report, initial mine development planned to commence in the near future, but is dependent on China’s coal markets which have been depressed during the last two years.

Mopanshan will be an underground coal mine aiming to produce 900 thousand tonnes of coal per year when full design capacity is reached.  Owned and operated by GQEDC, a 100 percent state owned company, the mine has targeted two primary coal seams, the 5 and 9 seam.  The calculated economically recoverable coal reserves within the mining area are estimated to be 60.75 million tonnes, providing an expected mine service life of over 66 years.

Gas content test data provided by mine management along with results of a methane adsorption isotherm test, were used to provide a frame of reference within which the potential gas volume of each coal seam could be estimated.  Gas resources were estimated for each of the coal seams by multiplying the volume of coal resources within the designated mining area to a probability distribution representing the range of gas content values.  The p50 total methane resource for the mineable coal seams at the Mopanshan mine is estimated to be 2,921.6 million cubic meters.

Production modeling performed for this study included the potential gas produced from a proposed series of 22 pre-mine drainage wells positioned vertically throughout the mining area and three gob drainage wells drilled annually over a ten year period.  The total estimated p50 CMM production over the project life is 165.9 million cubic meters of methane, available for use by the mine.

The Permian age stratigraphic sequence that contains the mineable coal seams is directly overlain by thick Triassic and Permian limestone beds.  In the Mopanshan region, the relentless dissolution of calcium carbonate from the limestone beds gives rise to a specific type of geologic terrain known as karst topography characterized by sinkholes, caves and underground drainage systems.  The water contained in these aquifers can pose safety concerns for miners and require that design of pre-mine and gob wells accommodate the need to hold back the water while drilling, and preserve the integrity of the well as it passes through karstic cavities.

The energy market in the Guizhou region was assessed to determine end-uses for the Mopanshan mine’s CMM.  China’s electricity consumption grew at a robust average rate of 11.1 percent from 2005 – 2011.  Electricity consumption within Guizhou is also on the rise, reporting a growth of 7.3 percent in 2013,  and it is reasonable to assume that Guizhou’s economy and its electricity consumption will grow within the projected eight to ten percent range for the country as a whole in the medium term.  Never-the-less, virtually all power generated by Guizhou CMM plants, is being distributed through the mining companies’ grids for their own consumption, and some mining companies with the capability to generate excess power have been forced to idle capacity due to their inability to reach interconnection and sales agreements.

End-use options for the CMM drained from the Mopanshan mine are limited as there is no existing infrastructure in the region that would enable the mine to transport produced gas to market.  This feasibility study proposes the mine consider on-site power generation using CMM fueled internal combustion engines.   The proposed power generation project operating 8,000 hours annually would generate 13.5 MW of electricity once the project reaches peak gas production.  The capital costs are estimated to be $27.47 million USD yielding an IRR of 45 percent and a payback period of 3.8 years.  The proposed power generation project is estimated to reduce CMM emissions by 397.4 thousand tonnes of CO2e over the project’s 10 year life.