Laserfiche WebLink
PROPOSED IN-SITU TREATMENT OF MINE POOL WATER <br />Background and Rationale <br />On December 14, 2010, the Division of Reclamation, Mining and Safety ("DRMS") issued to <br />Cotter Corporation (N.S.L.) ("Cotter") a letter containing an Adequacy Review (DRMS, 2010) <br />of the Environmental Protection Plan ("EPP") which Cotter had submitted to DRMS on July 31, <br />2010 (Cotter, 2010). This TR request has been developed in response to requirements of the EPP <br />Adequacy Review that relate directly or indirectly to the Division's characterizations of the <br />underground mine workings as a geologic containment facility for long-term containment, <br />stabilization, and management of mine pool water. Relevant requirements of the EPP Adequacy <br />Review (listed by Adequacy Review item number) are summarized and discussed as follows: <br />• Item 1(11): The Division indicates that the mine pool is contaminated because of disturbance <br />of toxic material in the underground mine, and characterizes the underground mine workings <br />as a "geologic containment facility" as well as an "impoundment". <br />Cotter disagrees that the flooded mine workings are an "impoundment under Hard Rock Rule <br />6.4.21(l)(c)." The term "impoundment" is not defined in the Mined Land Reclamation Act <br />("Act") or the Hard Rock/Metal Mining Rules. A review of statutory and regulatory <br />provisions, as well as the common meaning, does not support the Division's position. For <br />example, Section 34-32-116(7)(b) of the Act states that "[e]arth dams shall be constructed, if <br />necessary to impound water, if the formation of such impoundments will not interfere with <br />mining operations, damage adjoining property, or conflict with water pollution laws, rules or <br />regulations of the federal government or the state of Colorado, or any local government <br />pollution ordinances." This statutory provision indicates that the legislature considered <br />impoundments to be earthen dams. The regulations also indicate that impoundments were <br />intended to cover water diversions associated with earthen dams. See Hard Rock/Metal <br />Mining Rule 6.4.4(c). Cotter's construction of the term "impoundment" is consistent with <br />the common meaning. See J. Singer, Statutes and Statutory Construction 6`h Ed. § 47:28 <br />("Unless otherwise defined, it is usual to interpret the words as taking on their ordinary <br />contemporary common meaning"). Several dictionaries define "impoundment" as a body of <br />water, such as a reservoir, made by impounding. See <br />http://www.yourdictionary.com/in-ipoundment; <br />http://www.thefreedictionary.com/impounment. <br />It is important to recognize that pre-mining background ground water quality in the vicinity <br />of mineralized fault/fracture systems which later became disturbed by mine workings was <br />naturally "contaminated" for millions of years due to contact with mineralized rock. Mining <br />disturbance increased contaminant levels in these ground waters, primarily because <br />mineralized rock became exposed to oxygen and subject to oxidization and enhanced <br />leaching. The fundamental relationship between the geochemically reducing conditions and <br />ground water concentrations that existed prior to mining (which for uranium were likely <br />several orders of magnitude greater than current drinking water standards), and ultimately <br />attaining a state of geochemical equilibrium similar to that of original background water <br />quality in this area, provides a sound and scientifically supported rationale for maintaining <br />the underground workings in a flooded state. <br />1