2018-08-20_REVISION - C1980007 - Laserfiche WebLink

Home Browse Search

The E seam coal in the lease mods would be mined over a period of approximately 3 years, however E seam coal reserves in the modifications represent about 1.6 years of additional coal reserves based on the rate of mining currently employed at the West Elk Mine. Some variations to these timeframes may occur based on time needed for permitting, unforeseen mining/geologic circumstances, coal contract variability, etc. Reasonably Foreseeable Surface Use and Disturbances In recent years, the coal mines operating in the Somerset Coalfield have experienced the build up of methane gas in the underground workings after the rock strata have subsided into the mine void (called the gob). Under Mining, Safety and Health Administration (MSHA) regulations, mines are required to hold the methane levels below 1 % to ensure worker safety underground. Typically, the mine ventilation system cannot effectively keep methane levels within safe working range, therefore additional methane liberation methods have to be employed. On their leaseholds, the West Elk mine has used a system of methane drainage wells (MDWs) to assist in liberating methane from the underground mine. These MDWs are drilled from the land surface into the mine workings, and use an exhausting blower to pull gas from the mine. Drilling these MDWs requires construction of drill pads and temporary roads on the land surface. These features are on the landscape for 2 to 6 years, after which they are decommissioned, the land surface reclaimed and returned to pre -mining land uses. For the lease modifications, it is anticipated that MDWs will be needed. Other post -leasing surface disturbance that could be reasonably anticipated include exploration drilling, seismic exploration, ground water monitor well installation, subsidence, hydrology monitoring facilities, and access roads needed for these facilities. For the purposes of the cumulative effects analysis in this EIS, it is assumed that about 75 acres of surface disturbance would occur over the life of the lease modifications (expected to be about 25 years from lease issuance to lease relinquishment and final bond release). Site-specific locations of anticipated disturbance cannot be identified at the leasing stage due to the fact that a final mine plan has not been approved. For the purposes of this analysis, it is assumed that approximately 48 MDWs would be needed over the life of the lease modifications, corresponding to an estimated 48 acres of disturbance (assuming about 1 acre of disturbance per pad). Associated temporary road building associated with MDWs is estimated to be about 6.5 miles, corresponding to about 24 acres of disturbance assuming a 30 -foot average disturbance width for a temporary road with a 14 -foot running surface. It is assumed that any if any exploration drilling, staging areas, and ground water Sunset Lease Modification Biological Assessment