2023-10-30_PERMIT FILE - M2023015 (2)

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LONDON MINE M-2023-015 Exhibit U—Rule 6.4.21 Environmental Protection Plan This Exhibit includes: • Geochemical whole rock analysis including evaluation of leachability of the material through EPA Method 1312 SPLP, • Sorted rock mineralogical comparison (both of inert waste and product for off-site treatment), • Evaluation of water balance and climate which was exhaustively contested in the decree of non- tributary groundwater at the London Mine in a 13-year long hearing from 1974-1986, • Discussion of geological site specific conditions, • Presents 6 quarters of groundwater and surface water monitoring, • Provides the Storm Water Management Plan including Hydraflow calculations based on the climate data, incorporates the Spill Prevention and Containment Plan which is a part of the CDPS Permit which was published for public comment July 2019, • References the Consent Order IC160803 which was published for public comment by CDPHE August 2016, • Includes the Sampling Plan for the fines generated from crushing operations,and • References the previously submitted Exhibits to this Application, now being updated for reference herein. The proposed operation was determined to possibly constitute a Designated Mining Operation (DMO), and as such,would require an Environmental Protection Plan (EPP) in addition to the Mining Plan and Reclamation Plan. Portions of this Rule pertaining to subjects not applicable to this site or operation will not be included in this plan.The Applicant believes that the Operation will not use any designated chemicals,form any acid or toxic materials,or otherwise qualify as a DMO, but as a precaution is submitting this operation as a DMO out of an abundance of caution. The London Mine was abandoned in 1991 and since then has not generated acid drainage,with the average pH of the discharge around 8.0.The site does produce non-toxic concentrations of zinc at concentrations better than the Site Specific Stream Standards stipulated to by CDPHE and adopted by the WQCC(2004) but is exceeding the table value standards for ambient water quality. In the recitals to the Consent Order,the 2004 Stipulation for cadmium and zinc were never to be made more stringent by regulation, but nevertheless in good faith the Applicant is working to reduce loading to perform better than the 2004 Stipulation. (1)(a) The determination was made based on the fact that the operation will handle mineralized pre-mined waste rock, and which exposes the site to these materials during mining or reclamation. (See definition in Rule 1.1(1).)