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1171 0117721/017 10 Su000/t Den /son SL0EnVironmenla /Assessmenl Remand <br />Den /Son Sunday M /nes Grouo <br />was also submitted to the Dolores Public Land Office for review on June <br />27, 2008. Although the sampling and analysis plans that were approved <br />by the state are not identical to BLMs stipulated sampling activities, CDM <br />believes that this work addresses the same issues that BLM is raising in <br />the remand. Therefore, the characterization work conducted in <br />conjunction with the state mine permitting process is adequate to address <br />outstanding BLM issues. <br />Specific Comments <br />Comment 1 DeELIovment tuck -1whe d� <nps Existing dumps at the mines prior to 1979 were <br />constructed in a pre- regulatory environment that allowed for dumping of <br />unknown materials directly in contact with soil, bedrock and groundwater. <br />Dump rock characterization, with long term stability and environmental <br />monitoring and mitigation for both surface and subsurface concerns are <br />currently required. Additionally, bonding requirements at 43 CFR 3809.551, <br />require full bonding for reclamation, including both short and long term issues. <br />If this was a new mine application with no prior existing dumps, this report <br />would likely be the best available information. However, since mine dumps have <br />existed at this location for at least 30 years, a real world example exists at the <br />site, and simple deep trenching, or subdump drill sampling for water (in either <br />saturated or unsaturated conditions, if present) should provide evidence these <br />metals and potential waters have or have not had an effect on subdump soils and <br />ground water. Any dump expansion with potential for increasing any hazards <br />that may exist without long term mitigation (see performance standard at 43 CFR <br />3809.420 (b) (11)) is not permittable. <br />Discussion This comment implies that the existing development rock piles were <br />placed in direct contact with groundwater. Based on the data collection <br />activities conducted in 2008 and 2009, CDM is not aware of any data that <br />indicates that Sunday Mines Complex development rock is in direct <br />contact with groundwater. CDM requests data from BLM that supports <br />this comment. <br />This comment also implies that the historic placement of mine <br />development rock at the Sunday Complex Mines was conducted using <br />antiquated minin methods and that federal surface mine regulations <br />(43 CFR 3809) require different methods for development rock placement. <br />Placement of mine development rock in permanent stockpiles near a <br />mine remains an inherent and necessary mineral development practice <br />even in today's modern regulatory environment. In addition, long -term <br />mitigation and monitoring of rock piles is not warranted unless the rock <br />piles produce deleterious leachate. Denison has conducted extensive <br />characterization of the rock piles at the Sunday Complex Mines in <br />accordance with State of Colorado mine permitting requirements. This <br />data (CDM 2009a) has been provided to BLM as discussed previously, <br />Final Sunday Mines BLM Remand Letter.doc <br />