2012-12-20_GENERAL DOCUMENTS - C1981038

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With the approval of Technical Revision No. 45 in January of 2005, Division approval was given to suspend subsidence monitoring of the wide - spaced subsidence monument stations 14, 15, 16, 6, 81, 82, 83, 95, 99, DH -55, DH -65, and DH -68. With the approval of TR -45, the only required subsidence monitoring involves those stations associated with the Pitkin Mesa pipeline, namely, stations PL -1 through PL -7. The subsidence portion of the application is in compliance with the Regulations. XVI. Concurrent Surface and Underground Mining - Rule 4.22 This section is not applicable to the Bowie No. 1 Mine. XVIL Operations on Alluvial Valley Floors - Rule 4.24 The discussion of Alluvial Valley Floors can be found in Section 2.06 of Volume 1; in the AVF Appendix A, Volume 4 and in the Geo -Hydro Phase 2 studies. Identification of Alluvial Valley Floors The general area in which the Bowie No. 1 Mine is situated contains several deposits of alluvium. These alluvial deposits are derived from three sources: 1) Floodplain alluvium (Qal) along the North Fork of the Gunnison River; 2) Valley fill deposits (Qvf) along a portion of Steven's Gulch; and 3) Alluvial gravel (Qag) divided into three (3) age categories younger (Qagy), middle (Qagm) and older (Qago). The valley fill deposits are located along the North Fork Valley side slopes. The applicant has identified alluvial /colluvial deposits in a second area that is located along Steven's Gulch in the W' /2NW' /4 of Section 13, T13S, R92W. As identified in the Phase 1 AVF Study, the area is approximately 20 acres in size and is composed of valley fill deposits (Qvf). The mine has a well in this deposit that can pump 30,000 GPD from the alluvium /colluvium. Depth to water varies from about 7 feet in May to approximately 36 feet in February. The area is high and isolated, but has been used for pasture -hay meadow. The area is not flood irrigated, has not been flood irrigated, and is too high in elevation to be flood irrigated (at this elevation, the growing season is too short for the normal flood irrigated crops). Subirrigation is limited to areas along the stream channel itself. The area is determined not to be an Alluvial Valley Floor based on its lack of flood irrigation potential and lack of significant subirrigation. An additional area along Steven's Gulch which lies within and to the south of the mine permit area contains areas of alluvium. This area includes alluvial gravel deposits in Sections 24 and 25 (T13S, R92W) and the W' /z of Section 30 (T13S, R91W). Four separate deposits have been identified within this area, as shown on Map No. 2 -2. The two larger deposits, labeled Qagy and Qago, may meet the geomorphic criteria of Alluvial Valley Floors, but do not meet the water availability criteria for either flood irrigation or subirrigation. Due to the steep slopes, rocky surface, and lack of sufficient water, these areas cannot be flood irrigated. Regarding subirrigation potential, the field investigation to detect subirrigated species along Steven's Gulch did not identify any such species within these areas. Vegetation suggests subirrigation does occur along portions of Steven's Gulch, but these species are confined to the extreme channel bottom areas. Based upon this information, these two areas are found not to meet the criteria for Alluvial Valley Floors. These are older terraced deposits that have been dissected by stream channels, such that the channels have completely cut through the deposit. These areas are found Page 37 of 42