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Post -Mining Land Use <br />The post -mining land uses for the SPL are rangeland for enhanced domestic livestock grazing <br />and wildlife habitat. The reclaimed lands associated with the Phase III portion of SL7 have <br />vegetative cover composed of a variety of grasses, forbs, and woody shrubs. The seasonality <br />and forage characteristics of the vegetative species are suitable for the approved post -mining <br />land use. No significant weed problems or bare areas were identified. <br />SPL has implemented an annual grazing plan on reclaimed lands at the Yoast Mine since 2009. <br />SPL's grazing plan takes into account the available forage biomass. Livestock is stocked at an <br />appropriate capacity to leave no less than 50% of the available forage biomass. Grazing was <br />conducted annually from August through September. <br />The revegetation success standards were based on what would be necessary for the land to <br />properly function as grazing and wildlife habitat. Based on the achievement of the <br />requirements, the Division finds that the revegetation on the SPL Phase III reclaimed areas is <br />capable of supporting the approved post -mining land uses. <br />Evaluation of Hydrologic Impacts <br />In accordance with Section 3.03.2(2), the Division has evaluated whether pollution of surface or <br />subsurface water is occurring, and the probability of future occurrence of such pollution. The <br />evaluation considered information in the following documents: the Probable Hydrologic <br />Consequences section of the permit application, Annual Hydrology Reports submitted by the <br />operator, the Division's Annual Hydrology Report review memoranda, and documents in the <br />SL7 bond release application and file. The results of the evaluation are summarized below. <br />Basic Standards Interim Narrative Standard for Ground Water (CWQCC Regulation 41.5(c) (6)) <br />The Yoast Mine alluvial ground water point of compliance (GWPOC) in the Grassy Creek <br />alluvium is well SGAL70. The alluvial GWPOC in the Sage Creek alluvium is well YSAL3. <br />The Phase III areas are in the upper and lower reaches of the drainage basins, therefore, a review <br />of the statistical summary of the water quality of SGAL70 and YSAL3 was completed based <br />on water quality data presented in the Annual Hydrology Reports for the Yoast Mine. Based on <br />the data collected, ambient values for both GWPOC were found to be lower than the Colorado <br />Water Quality Control Commission (CWQCC) Regulation 41 standards. The groundwater quality <br />at SGAL70 met water quality standards for all parameters except for dissolved cadmium and <br />dissolved selenium, where three samples for dissolved cadmium exceeded the standard. However the <br />lab detection limit is above the standard. None of the exceedances were associated with measurable <br />values of cadmium and cadmium has not historically posed an issue at the Yoast Mine. The <br />excursion was deemed due to elevated concentrations in the lab batch or unrelated instrument <br />interference. The selenium excursion was also deemed an anomaly as no other sample during the <br />previous five years exceeded the standard. For the past three water years (2016 to 2019), no <br />standard was exceeded at YSAL3. <br />SPL does not have a groundwater point of compliance for ground water in bedrock stratigraphic <br />units, based on the absence of the potential for the mine to negatively impact the quality of <br />bedrock ground water. The low hydraulic conductivities of the bedrock units and confining <br />layers isolate mine -impacted water -bearing units from the nearest usable aquifer, the Trout Creels <br />Sandstone, which lies approximately 300 to 400 feet below the Wadge Coal seam and <br />approximately 60 to 100 feet below the Wolf Creek Coal seam. <br />Permit Number C-1994-082 Page 17 of 23 <br />