2012-08-21_REVISION - M1980244 (32)

Home Browse Search

mice and voles), ground nesting birds, reptiles and other wildlife species. These rock pile structures will be field engineered during reclamation activities, and the specific locations / approximate sizes are not detailed as part of the final reclamation plan for the Cresson Project. 36. Page 4 -8, 2nd and 3rd bullets — The statement that "All precipitation water infiltrating to ground water through MLE2 mine facilities ... will pass by subsurface flow paths through the diatreme ..." and a similar statement in the third bullet, appears inconsistent with the fact that some proposed MLE2 facilities (e.g., East Cresson Mine Wildhorse Extension, north edge of East Cresson Overburden Storage Area, and SGVLF — Adsorption, Desorption and Recovery Plant (ADR) and underdrain ponds) will extend beyond the delineated edge of the diatreme (reference Drawings C -4, C -4a and C -7). Please provide some narrative to correct or substantiate the statements in the second and third bullets. RESPONSE. As presented in more detail in Section 2.5 of Appendix I of Volume H of the Application, the conceptual model of the hydrology of the District is a large diameter "well" (the Diatreme) that collects infiltrating precipitation from the surface of the Diatreme and adjacent portions of the surrounding lower - permeability Precambrian rockmass, with some of the infiltrating water eventually reaching the regional groundwater system that is bisected by the Carlton Tunnel. The proposed MLE2 facilities (e.g., East Cresson Mine Wildhorse Extension, north edge of East Cresson Overburden Storage Area, and SG VLF — Adsorption, Desorption and Recovery Plant (ADR) and underdrain ponds) may extend beyond the delineated edge of the Diatreme (as reference Drawings C -4, C -4a and C -7), but are within the surrounding lower permeability Precambrian rockmass wherein some infiltrating water migrates towards the regional ground water system. 37. Page 4 -19, 3rd paragraph — Please elaborate on the last statement the historic mine features have some influence on the current groundwater quality. Is this influence potentially significant? If so, can it be quantified? If not, is it important? RESPONSE. Unavoidably, the Cripple Creek Mining Overlay District ( "CCMOD') is fraught with hundreds of interconnected historic mine features (all underground workings). The impact to ground water, and, for that matter, also surface water quality on a localized and regional basis is virtually impossible to quanta. The fact that many underground workings are located off of CC &V property, but yet still in the CCMOD exacerbates the complexity and feasibility of such an undertaking. Regarding the potential impact significance of historic mine workings on ground water quality, localized influence is likely, but again, quantification would be extremely difficult icult if not all together impossible. The possible importance would be entirely dependent on specific, as found conditions. However from an overall system perspective please refer to the extensive discussion provided in the amendment application. 38. Page 5 -5, Table 5 -1 — Should the 7`b row from the bottom refer to reclamation of Arequa Gulch Adsorption, Desorption and Recovery Plant (AGADR) Facilities, not just AGADR? RESPONSE: Yes, the 7th row from the bottom should refer to the reclamation ofArequa Gulch Adsorption, Desorption and Recovery Plant (AGADR) Facilities; a revised Table 5 -1 is included as Attachment 8 to reflect that clarification. 39. Page 5 -7, 4d' paragraph — Should the volume of potentially suitable soil in the MLE2 development be 1.9 "million" cubic yards? RESPONSE: Yes, for clarification purposes, the volume ofpotentially suitable soil in the MLE2 development should be approximately 1.9 million cubic yards as discussed on page 5-7, 4th paragraph. As revised, the 7th row from the bottom should refer to the reclamation of Arequa Gulch Adsorption, Desorption and Recovery Plant (AGADR) Facilities; a revised Table 5 -1 is included as Attachment 8 to reflect that clarification.