2001-12-11_PERMIT FILE - C1980007A (2)

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3.4.A.10.2 B Seam Operations The B seam mine plan is shown on Exhiblt 3.4.A.1. The B seam operations will be confined to the existing 5-year permit area with the exception of the small boundary change for the main entries. In the area where mining in the B seam is planned, two mineable seams exist-the B and the F. Most or all of the mineable F seam has been or will be mined oitt by the time retreat mining begins in the B seam; however, even if some mineable E seam remains above planned B seam mining, no impacts which would preclude later mining of the remaining F seam above the mined out portion of B seam are anticipated. This is due to the relatively thick interburden (380 to 400 feet) between the F and B seams. Geotechnical analyses performed by J. E. T Agapito and Associates show that under worst case conditions, the F seam will not be significantly affected by mining in the B seam. Geotechnical work as well as mining experience in tl~e E seam indicates the conditions will be good. Geotechnical design and analyses are discussed in Section 3.4.A.4. As discussed in Section 3.4.A.4, the three mineable seams in the Mt. Gunnison mine block have the potential to be mined in either ascending (bottom to top) or descending (top to bottom) order. Originally, plans were to mine the three seams in descending order. Improved mining technology, improved geotechnical design and • analyses methods, and experience mining the E seam in the mine block have provided a means to better evaluate mining the seams in ascending order. Experience mining the B seam in the area planned should provide additional information with which a final deter- mination as to seam mining order for the mine block can be made at a future date. For the purpose of this submittal, no mining (life of mine) in the B seam is shown outside the 5-year permit area. If experience shows B seam mitring is possible beneath the mineable E seam without significantly affecting the resource so as to make it unmineable, permits may be revised accordingly. If experience in the B seam shows mining will damage the E seam resource so as to preclude future mining, original plans to mine the seams in descending order will remain in place. 3.4.A.10.3 E Sean Information has been submitted in this application on geology, mineable areas, geotechnical design and analyses, hydrology, and other information. This has been done to assess mining in the B seam and to provide an overall picture of the interaction of the three seams in the mine block. Currently, there are no plane to mine the E seam in the Mt. Gunnison mine block, therefore, no mine plans have been provided. LJ