Laserfiche WebLink
COLORADO LEGACY LAND <br /> $CHWARTZWALDER MINE <br /> EXHIBIT E. RECLAMATION PLAN <br /> E.1. CONCEPTUAL CONSIDERATION <br /> In accordance with Condition #2 of the Succession of Operators Plan, (letter dated February 20, 2018), a <br /> conceptual site model (CSM) of the Schwartzwalder Mine was provided to Colorado Division of Reclamation, <br /> Mining and Safety(DRMS)on November 6,2018 and is provided in Appendix 1.The CSM defines and describes <br /> the key hydrologic and geochemical mechanisms that are expected to influence/control the flow and chemistry <br /> of water in and around the Schwartzwalder Mine.A summary of the CSM is provided below. <br /> • Uranium mining of the Schwartz Trend occurred from 1953 to 2000.The Schwartz Trend is a thin band <br /> of brittle garnet biotite gneiss and quartzite between the East Rogers and West Rogers Faults. <br /> • The Ralston Creek Alluvium is largely confined to stream deposits of limited thickness and extent along <br /> Ralston Creek. <br /> • Colluvium and weathered bedrock groundwater are contained in a thin veneer on hillsides and in <br /> drainages tributary to Ralston Creek,which are localized,of limited areal extent,and strongly affected <br /> by seasonality. Groundwater in low-permeability bedrock is associated with regional faults and <br /> associated fracture systems that control the limited occurrence. <br /> • Climate and hydrology play a key role in any hydraulic connections between the mine workings and <br /> Ralston Creek. <br /> o Average annual precipitation of 18.66 inches per year (in/yr) is offset by an average <br /> evaporation rate of 35 to 40 in/yr. <br /> o Excess precipitation flows towards Ralston Creek. <br /> • Currently a pipeline diverts Ralston Creek from upstream of the mine area to below the mine area.This <br /> bypass pipeline prevents Ralston Creek from interacting with contaminated alluvial soil.The alluvial <br /> soil was identified in Technical Revision 14 as having the potential to leach uranium to shallow <br /> groundwater and adversely affect Ralston Creek.Upon the completion of the alluvial valley excavation <br /> project,this bypass pipeline shall be removed,and Ralston Creek will flow through its natural channel. <br /> • Historical sources,e.g.,waste rock dumps and alluvial waste rock fill,have contributed to mass loading <br /> of Ralston Creek,with uranium and metals,and affected the alluvial groundwater. <br /> o Waste rock dumps: In 2020, CLL constructed a diversion channel on the North Waste Rock <br /> Pile (NWRP). This channel diverts run-on water around the NWRP. Mass loading from the <br /> NWRP into Ralston Creek are considered de minimus. <br /> o Alluvial waste rock: As described above, a by-pass pipeline prevents Ralston Creek from <br /> interacting with the contaminated alluvial valley soil. Similarly,alluvial groundwater in the <br /> permit area is captured by a main sump system and sent back into the mine.These engineering <br /> controls shall be removed once the onsite source is addressed. <br /> o The historical sources have been reclaimed or are in the process of being reclaimed. The <br /> reclamation activities combined with the upstream diversion have essentially eliminated <br /> mass loading to Ralston Creek. <br /> JUNE 2021 13 AMENDMENT 6 <br />