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COLORADo LEGACY LAND <br /> The Division has the following comments regarding the revised Conceptual Site Model presented in <br /> Appendix 1: <br /> a.In its response to the Division's adequacy item#29(b),particularly to the question of whether sampling The previous operator,Cotter,previously completed several environmental investigations to evaluate the potential connectivity <br /> for tracers was conducted at any of the groundwater or surface water monitoring locations,the operator of the Mine Pool and Ralston Creek. Please see previous response to Comment#14 and Section 8 of the Schwartzwalder Mine <br /> states"While tracer sampling was not performed in monitoring wells or surface water near the mine,the Environmental Protection Plan(Whetstone Associates Inc.,2016)for more detail. <br /> hydraulic head in the mine pool is lower than the hydraulic heads associated with these features,so it is <br /> highly unlikely that tracer would ever be found at these sampling locations".The Division understands the Additional tracer studies are not needed to determine if CLL has achieved physical and chemical stabilization of the mine pool. <br /> hydraulic head in the mine pool is lower than the hydraulic head at monitoring locations within the permit Data presented in AM-06 demonstrate that these objectives are met with CLL's current management approach. CLL has <br /> area.However,there are four surface water monitoring locations along the creek downstream of the mine maintained a dewatered mine pool below the regulatory limit(Figure E-3)such that a hydraulic mechanism whereby mine pool <br /> site which could potentially be affected by water from the mine workings(if viable migration corridors water can exit the workings and migrate toward Ralston Creek and Ralston Reservoir does not exist(Appendix E and Figure E-4). <br /> exist).Given the known hydrogeology of the site,are there any tracer studies that could be performed Furthermore,CLL can maintain the physical and chemical stabilization of the mine pool by operating the existing water <br /> specifically to investigate potential migration corridors in which water from the mine workings interacts treatment plant facility 6 months a year,or less. <br /> with the creek downstream of the mine site? <br /> Exhibit F-Reclamation Plan Map (Rule 6.4.6): <br /> The Division has the following comments on the Figure F-1 Reclamation Plan map provided: <br /> a.Please explain the"diversion structure"shown to remain along the southern edge of the creek.Is this a. Yes this"diversion structure"was the Ralston Creek bypass pipeline and North Waste Rock Pile channels. The legend of <br /> structure meant to represent the existing bypass pipeline?If so,please remove it from this map as the the figure has been revised for clarity.The text in AM-06 has been revised so it's clear that CLL intends to leave the <br /> proposed reclamation plan includes removing this pipeline for reclamation.If this structure represents bypass pipeline and associated infrastructure in place at least until it has been confirmed that surface water flow across <br /> something else,additional clarification on the map is needed to differentiate it from the NWRP stormwater the reclaimed site does not create an exceedance of uranium at BPL. <br /> diversion channel (also identified on the map as"diversion structure") <br /> b.Please identify the areas to receive each of the revegetation plans proposed for reclamation. <br /> b. At this time CLL cannot identify the exact area's that will receive each of the revegetation plans(seed mix,trees,and <br /> 16 shrubs)because the extent of the alluvial valley reclamation project is not known. CLL shall prepare a site-specific <br /> planting plan in coordination with DRMS,USACE,and USFW once the excavation project is complete. Figure F-1 has <br /> been revised to illustrate the anticipated planting area,which corresponds to disturbed surface features at the site. CLL <br /> expects this disturbed area to receive the majority of the revegetation planting,however planting may extend to other <br /> areas along Ralston Creek within the Mine Permit Boundary. <br /> c.Please ensure all structures proposed to remain for reclamation(e.g.,upgradient cutoff wall, <br /> riprap/grouted boulder areas,bridges,culverts,wells,buildings,powerlines,pipelines,roads,graveled or c. Revised as requested. <br /> paved parking areas)are shown on this map. <br /> d.Please show the location of the Jeffrey Air Shaft and any structures currently installed at the surface of <br /> this shaft which are proposed to remain for reclamation. d. Revised as requested. The insert showing the water treatment plant infrastructure has been updated to show the Winch <br /> and Cable Housing for the Dewatering Pump,which in installed in the Jeffery Air Shaft. <br /> Exhibit F-Reclamation Plan Map(Rule 6.4.6): <br /> 17 Please provide a separate reclamation plan map depicting a detailed grading plan for the valley floor.This As described in Exhibit E,the extent of contamination in the alluvial valley is unknown,therefor CLL cannot provide a detailed <br /> map should show how the valley floor will be reconfigured to establish positive drainage to the creek.This grading plan for the valley floor at this time. The text in Exhibit E has been revised to: (1)affirm CLLs commitment to reclaiming <br /> map should also show any structures proposed to remain in the valley. all disturbed lands in accordance with all regulatory requirements and(2)commit to providing DRMS a detailed grading plant for <br /> the alluvial valley once excavation work is complete. <br /> Exhibit L-Reclamation Costs(Rule 6.4.12): <br /> The Division has the following comments specific to the Water Treatment Plant Operations section: <br /> 18 a.The operator has removed costs for demolishing the water treatment plant since the proposed a. The costs to demolish the water treatment plant for$55,000 have been added back into Table L-1.CLL is also including a <br /> reclamation plan includes continued operation of this plant.While the Division agrees that removing copy of this lump-sum bid in response to these comments. <br /> demolition of the water treatment plant is consistent with the proposed reclamation plan,the Division <br /> must continue to hold costs for this task until the operator has provided demonstration that leaving this <br /> PAGE 6 OF 12 <br /> r <br />