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Comment/Objection Narrative* <br /> 2/22/2023 <br /> To:Colorado Department of Reclamation, Mining,and Safety, <br /> We are pleased to submit The Watershed Center comments on Colorado Milling Company's recently completed <br /> conversion application for permit#M1994117 at the Gold Hill Mill.The Watershed Center(originally named <br /> Lefthand Watershed Oversight Group)is a local watershed group that has been directly involved with water <br /> quality concerns in Left Hand Creek.As a long-time watershed stakeholder,please consider our comments as <br /> they relate to water quality concerns with the Gold Hill Mill application. <br /> Background Information <br /> The Watershed Center has been overseeing the Captain Jack Mill superfund clean-up project since 2005 and <br /> subsequently monitoring water quality,aquatic life and habitat in the upper reaches of Left Hand Creek and <br /> surrounding watershed.Water quality and aquatic life in upper Left Hand Creek are directly impacted by <br /> abandoned mines,with the most notable source being Captain Jack. In the Watershed Center's time working <br /> on Captain Jack for over 15 years,we have had emergency events such as a fishkill in 2018 and lessons <br /> learned about the type of treatment, monitoring and response time that's necessary to alleviate water quality <br /> concerns. <br /> Comments <br /> 1.We are not confident that there will be no acid mine generation in the Times-Wynona mine shaft during <br /> milling operations,assuming that the mine pool elevation will increase from the current level.The Section C <br /> Mining Plan states that,"Mineralization characteristic of the Boulder Country deposits is not generally acid <br /> producing."This does not align with our experience at the nearby Captain Jack Big Five Tunnel. In the Big Five <br /> Tunnel,acid mine generation in the mine pool is the crux of the in-situ treatment. Moreover,during Captain <br /> Jack's ongoing in-situ treatability study, monitoring showed that increasing the mine pool elevation exacerbated <br /> acid mine generation by exposing historically dry sections of the mine shaft to water.We request the applicant <br /> demonstrate their confidence that the Times-Wynona mine workings are not composed of acid generating <br /> material and that the current-and-future increased mine pool elevation are-and-will not produce acid mine water. <br /> 2.We are concerned about mine pool stratification in the Times-Wynona mine shaft. More specifically,we are <br /> not confident the Monitoring Plan for the W-2 location will detect water quality concerns if stratification occurs <br /> and the Mining Plan for the Times-Wynona could be revised to homogenize mine pool water. From our <br /> experience at Captain Jack,we have learned that mine pool water quality stratifies without circulation. Highly <br /> acidified water could go undetected if water quality monitoring only occurs in one area of the mine pool or <br /> without appropriate circulation.We request the applicant consider, 1. revising their Monitoring Plan to add <br /> sampling locations at W-2,the Times-Wynona shaft to sample from multiple elevations in the mine pool,and 2. <br /> revising their Mining Plan to include a circulation system in the Times-Wynona mine pool in order to <br /> homogenize water quality. <br /> 3.We are not confident in the timeliness and preparedness of the Water Monitoring Plan's Exceedance Plan to <br /> detect and respond to exceedances,specifically in the case of an emergency(e.g.mine water release)that <br /> could impact water quality of Fourmile or Left Hand Creek.The Appendix C Water Monitoring Plan explains that <br /> in the event of a detected exceedance,follow-up monitoring will occur to investigate specific parameters of <br /> concern.The timeliness and preparedness of this Plan does not align with our experience at Captain Jack. <br /> From our experience at Captain Jack,the fishkill in 2018 was a result of highly acidic water(stratified in the <br /> mine pool)entering the creek during a managed mine-pool release. In this situation, monitoring did not detect <br /> the issue until it was too late.The follow up actions included immediately shutting down the release/operations <br /> followed by construction of an ex-situ water treatment facility that took months to be operational.The treatment <br /> facility is still on site today to mitigate future exceedances or in case of emergency.We request the applicant <br /> consider revising their Exceedance Plan to include 1.shorter analysis and reporting turnaround time when <br /> monitoring exceedances and 2.add a list of potential actions that may be implemented in the case of an <br /> exceedance and/or emergency situation(e.g.cease operations,external treatment facility). <br /> Thank you for considering our comments and requests in your application process.We look forward to your <br /> responses. <br /> Thank you, Mark Schueneman(Former Board Member,The Watershed Center) <br /> Permit Number* <br /> Enter valid letter and then numbers,for example M1977999, M1999777UG or C1981201. <br /> M1994117 <br /> Permitting Action Type <br /> Select revision type or leave blank if comment pertains to a new permit application or NOI <br />