2023-09-07_REVISION - M1990057 - Laserfiche WebLink

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Welborn Sullivan Meck&Tooley&Leadville Sanitation 6 June 9,2023 CDRMS review process. UMC is confident that this final document—which will form the basis of plant operation will go a long way to address the above-mentioned concerns. Air Quality The Applicant's expanded operations and handling of ore threaten to impact the District's wastewater treatment facility with airborne heavy metals and toxic particulates in the form of fugitive dust leaving the Applicant's property. (4) To the District's knowledge, although the Leadville Mill may have been permitted to process 200 tons per day, it rarely ran continuously at anything near that amount of throughput. (5) The amount of particulates leaving the Mill property will be much higher than it ever was in the past. (5) Section 4.3.7 of the Application addresses dust control, but only within the Mill buildings. (6) The Application also indicates that there will be three ore stockpiles, one topsoil stockpile, and one ECS overburden stockpile. The District is concerned that handling large amounts of ore outside will lead to dust blowing onto its polishing pond and aeration basin, potentially impacting its water quality and operations. (5) Dust from the road running near the District's property boundary and polishing pond is also a concern. At a minimum, this road should be paved. The District is already hard pressed to meet compliance limits imposed by CDPHE. See JVA Memo. JVA Reference: (7) Since the Mill is located directly adjacent to the District's WWTF, the wind transport of metals from trucks entering and leaving the facility as well as ore, topsoil and overburden stockpiles and dust from the crushing facility could have detrimental effects and possibly contaminate the open air wastewater treatment basins at the WWTF. While the applicant proposes dust control for the mill and crusher buildings, JVA does not believe this will be an effective method for removing low level metals from the air. Effects from metals transport by air to the WWTF could be seen immediately or could occur over a period of time since the District has extremely low level metals limits in ug/L and is required to monitor metals on a frequent basis in the wastewater effluent and report this information to CDPHE. Response: 4. Correct. The Leadville Mill was originally permitted to treat up to 70,000 tons of ore per year, e.g., 70,000 ton/year over 350 operating days/year = 200 tons/day. When operating, the nominal production rate was on the order of 40 to 50 tons/day. 5. Correct. By virtue of operating at a much higher rate, it stands to reason that dust emissions will be higher. Also, the reviewer is correct. Outdoor dust mitigation discussion was inadvertently not included in the permit application. This was also pointed out by CDRMS during their review. UMC is addressing this with CDRMS and it will be included in the revised permit document — which will also address other CDRMS questions. Dust mitigations will include the following. o Dust mitigation will be per the APEN design criteria. o All haul trucks will cover their loads prior to departing the Penn mine dump area. o Trucks will access the mill site from the AVS Project entry-located about 2,300ft East of the WWTF entrance. The haul road will be constructed of coarse (>3/8inch) slag material which will minimize dust generation. o The haul road will be kept watered and sprayed with surfactants, as required.