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methane liberated from the mine via gob vent boreholes and ventilation air, as VAM. While many of <br />Arista's assumptions seem reasonable and applicable, many of the costs used in the economic analysis <br />seem excessive and unnecessary. Further, the study did not recognize that some of the costs included in <br />the analysis should be considered as a "cost of mining". These costs would be accrued as activities which <br />are a routine part of normal mining procedures at West Elk and should not be chargeable to a methane <br />use project. The end uses considered for the gas in the Arista study were: <br />• flaring (destruction), <br />• generating electricity for use at the mine, and <br />• conversion of the methane into LNG for sale into wholesale or retail markets. <br />No consideration was given to selling the electricity into the regional grid, and subsequently, none of the <br />options proved viable under the conditions considered. In addition, a study by the Verdeo Group <br />commissioned by the USFS and the USBLM was carried out to look at the viability of siting VAM <br />destruction technology at one of the exhaust shafts to destroy the methane and sell the carbon <br />emission reduction credits on the markets in operation at the time. Verdeo Group also evaluated the <br />options for selling any emission reduction credits generated from other end-use options under the <br />compliance cap -and -trade programs that were emerging in 2009. <br />In 2010, Power Consulting, an independent group, was contracted to review and comment on the <br />inputs, assumptions and conclusions made by these organizations. They concluded that the costs <br />offered by Arista/MCC were extremely high and unreasonable, and by lowering the costs and <br />incorporating revenue from the sale of environmental attributes, all of the end-use options evaluated <br />could meet MCC's economic thresholds. <br />MWCC Methane Emissions Data Reported under Subpart FF <br />All greenhouse gas (GHG) data reported by U.S. coal mines under the Subpart FF reporting rule is <br />available on the U.S. Environmental Protection Agency's EnviroFacts site for the years 2011 through <br />2016; recorded first by mine, and then by source (individual borehole or vent shaft). Ventilation data is <br />reported quarterly, including total air flow, and in a different table, methane concentration. Drainage <br />data is reported weekly, with volume and concentration data also in different tables. All data is reported <br />in units of standard cubic feet per minute (scfm), a common unit used in the mining industry to describe <br />flow of air and other gases. This data is collected from GVBs that were drilled above longwall panels <br />active during each of the years 2011 through 2016, and from the Deer Creek ESM shaft and the Sylvester <br />Gulch exhaust vent shaft. The locations of the GVBs and vent shafts can be seen on Map 1. Other data is <br />also available such as temperature, pressure, and type of monitoring device used to record the data, but <br />was not included in this study. <br />MCC uses the term "methane drainage well", or MDW, when referring to gob drainage wells, wells <br />drilled from the surface to intersect sections of the mine where coal has been extracted. The industry <br />standard term is "gob vent borehole", or GVB, which is the term used in this study to distinguish from <br />pre -mine drainage wells that could be drilled in advance of mining. <br />3 <br />