Application of Methodology and Regional Assessment of CMM and AMM Potential

Science Center Objects

This project developed assessment methodologies based on available data from Northern Appalachian basin. The assessment was conducted on two adjacent panels of a longwall mine that operated in Pennsylvania. The methodology was verified with the existing data and by cross checking the results of the software and probabilistic calculations.

Although the results were realistic and were in agreement with literature and with reported MSHA and EPA data, at least for the ventilation emissions, it is always better to validate the methodology with another mine and to expand the assessment to a larger district outlined in a coal basin, and then to a national scale.

Objectives

This task has two main objectives. The first is to assess the active and abandoned mines especially the ones producing gas in a district that will be outlined in a coal basin with the methodology developed. This will provide the opportunity to further validate the methodology and to calibrate it with any aspects that were not foreseen during development of the CMM and AMM assessment methodology. The second objective is to analyze the CMM and AMM resource potential from an economic point of view and to map them for investment decisions to complement both the energy and the socio-economic aspects of this topic.

Methodology

In this task, a large mine district, preferably having both active and abandoned mines, will be selected. Mine information and distributions of panels, ventilation points and quantities will be sought from the local Mine Safety and Health Administration (MSHA) district offices. The geological and geomechanical information of overlying strata will be gathered to define gas emission zone, its size and gas in place. These site specific information will be gathered from USGS, U.S. Environmental Protection Agency (EPA), State Geological Surveys, and MSHA records. When data is scarce or is not available, software tools will be used to estimate missing parameters that are needed by the methodology.

As an additional study to assessment of the mine, an economic analysis and mapping of coal mine and abandoned mine methane resources will be performed. Economic analysis will be based on the produced gas quality, location of the mine, and the available technologies that can utilize the gas for energy production. Mapping will be performed using geographical information system.

Useful Links

Methane Control and Prediction Software

Coal Mine Methane Review Paper

US EPA’s Coal Mine Methane Cash Flow Model

UNECE Coal Mine Methane

Key Findings and Accomplishments

Application of assessment methods to the case study showed that, although the methods, nature of the data, and data sources were different, the assessed amounts using geostatistical and probabilistic methods produced similar mean gas in place values in gas emission zone of the panels. The difference between the calculated values in some cases was mostly due to the use of mean values and standard deviations of data population from data of a larger area that included all variations that may not be relevant to the assessed panel areas. Further, production rates of gob gas ventholes predicted by the software were very close to the mean of the monitored production rates.

The recovery potential of the estimated abandoned mine methane resource was evaluated starting at the end of mining operations using an exponential decline. The analyses forecasted cumulative volumes of methane and the production life of the wells.

Economic analysis for electricity generation for the case study was performed. Results showed that the projects can be profitable depending on the gas availability, carbon credits and the price of the electricity.