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As stated by CCC in the response to the Division’s review of the 2007 – 2009 AHRs, a limited
<br />number of low impact spoil springs are expected to develop occasionally, but the aerial extent of
<br />these and the low level of flow (sometimes non-existent flow) will have a very minor impact on
<br />surface (and shallow ground water or perched aquifer) quality and quantity in the future. The
<br />Division has witnessed nothing to contradict this statement and does not anticipate that these
<br />spoil springs are causing or will cause significant impacts on receiving waters.
<br />
<br />Findings on Protection of Hydrologic Balance
<br />
<br />Based on the foregoing observations, the Division finds that the Colowyo Mine has minimized
<br />disturbance of the hydrologic balance in the SL-05 bond release area and prevented material
<br />damage outside the permit area. The Division also finds that the Colowyo Mine has not caused
<br />hydrologic changes that adversely affect the approved post-mining land use in the permit area.
<br />
<br />Topsoil
<br />
<br />
<br />On February 22, 2011, Colowyo submitted a revision to the SL-05 application removing 3.1
<br />acres associated with topsoil stockpile 15G and associated access corridor. Runoff from topsoil
<br />stockpile 15G has previously been demonstrated to meet sediment control requirements as a
<br />small area exemption. Removal of Topsoil stockpile 15G and associated travel corridor
<br />addressed the Division’s Item No. 1 concern.
<br />
<br />Revegetation
<br />
<br />The 40 reclamation blocks, totaling 979.47 acres, included in the Partial Phase III Bond Release
<br />SL-05 are EP001, EP002, EP003, EP004, EP005, EP006, EP007, EP008, EP009, EP010, EP011,
<br />EP012, EP013, EP014, EP015, EP016, EP017, EP018, EP019, EP020, EP021, EP022, EP023,
<br />EP024, EP025, EP026, EP027, EP028, EP029, EP030, EP031, EP032, EP033, EP034, EP035,
<br />WP001 (comprised of WP001N and WP001S), WP002, WP005, WP006, and WP007. Thirty-
<br />five of the reclamation blocks are located at the East Pit and account for 924.55 acres. Five of the
<br />reclamation blocks are located at the West Pit (the West Pit Fill) and account for 54.92 acres.
<br />The locations of the reclamation blocks are shown in Exhibit 1 – Phase III Bond Release Map in
<br />the SL-05 application. The reclamation blocks were seeded between 1978 and 1999. The seed
<br />mix used on the reclamation blocks is included in the SL-05 application in Table 2 (Tables 2.05-
<br />7 and 2.05-8 in the Colowyo Coal Mine permit). The post-mining land use for the Phase III
<br />Bond Release area is rangeland, as defined by Rule 1.04(71)(c).
<br />
<br />The Colowyo Mine uses two reference areas for the comparison of success of their reclamation
<br />blocks. The reference areas are the sagebrush reference area (established in 1981) and the
<br />mountain shrub reference area (established in 1980, which is further separated into a mesic
<br />aspect and a xeric aspect). Success standards are based on a weighted average of the pre-mining
<br />vegetation communities in each reclamation block (as shown on Maps 3 and 4).
<br />
<br />Proposed Decision and Findings of Compliance 25 July 2012
<br />Partial Phase III Bond Release Sl-05 Page 9
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