GENERAL48195 - Laserfiche WebLink

Home Browse Search

_~ II. Background The proposed Trapper Mine is located in Moffat County, Colorado located approximately six miles southwest of Craig, Colorado. The permit area contains 10,335 surface acres, all of which is private surface. Coal will be transported by truck from the Trapper Mine facilities to the Craig Power Station which is immediately adjacent to the permit area to the north. The proposed operations will utilize surface mining methods. Six coal seams of the Williams Fork Formation will be mined to yield a production rate of 2.3 million cons per year. All surface mining operations are scheduled for the five permit term. The CMLRD and the OSM, in the course of their reviews, identified issues which require clarification. These issues were: I) a delay in contemporaneous reclamation in terms of backfillirig and grading; 2) the methodology for evaluating herbaceous cover and productivity; 3) the overburden swell factors; 4) the incorporation of the post-mining surface and 5) the configuration of the post-mining topography. 1. A delay in contemporaneous reclamation, in terms of backfilling and grading, was proposed by the applicant. The reasons cited were: variations in pit lengths and cycling times and the need to remove interburden from above recoverable coal seams. The Trapper Mine is mining three pits and multiple coal seams. Tlie longest pit is 4500-6000 feet and requires cycling times of 230-345 days. The • sho rtes.t pit is 700-3400 feet and requires cycling times of 30-80 days. The cycling time is defined as the amount of time the dragline makes successive cuts, removes overburden and Snterburden and creates ungraded spoil rows. These variations will c+ause the pits to remain active from a minimum of 80 days to a maximum of 345 days. After interburden and overburden removal, grading will progress such that there will be no more than four ungraded spoil rows, including the active spoil row at any time in each pi[. The fourth spoil row will act as a buffer zone between stripping and regrading operations, thus preventing the disturbance of any regraded ar~aas with newly excavated material. The justification for the variance, detailed on page 3-37 to 3-40 in the MRP, was reviewed by the C~II.RD and the request was granted. 2. A method for evaluating revegetation success for herbaceous cover and productivity was proposed by the applicant. The method used standards derived from linear regression techniques and was designed to provide criteria for revegetation success. After much discussion between the applicant and the G`II.RD, the C.`iLRD concluded that the linear regression technique proposed is no[ an appropriate application of the methodology. The method was, therefore, stipulated (page 49-50 of CMLRD's Decision Document). 3. The verification of overburden swell factors. The applicant presented calculations indicating a projected swell factor of 25% for the overburden in post-mining topography. The calculations used ty the applicant to predict the overburden swell and. independent determinations made by the CMLRD were not identical. Therefore, to verify the predicted swell factor, two stipulations were imposed (page 52-53 of CMLRD's Decision Document).