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Non-Tributary Support: Cash Mine Borehole AdrianBrown <br />4.4.2 Allowed Annual Amount of Withdrawal <br />A further method of evaluating whether there is material injury to other water rights is to evaluate <br />whether the proposed extraction meets the Allowed Annual Amount of Withdrawal under Rule 8 of the <br />Statewide Nontributary Ground Water Rules25. While Rule 3(C) states that "(t)hese rules do not apply to <br />a permit sought pursuant to the provisions of Section 37-90-137(7), C.R.S." [i.e. mine dewatering], if the <br />proposed extraction is less than the Allowed Annual Amount of Withdrawal this would be a further <br />indication of lack of material injury of the withdrawal. <br />Rule 8 (A) of the Statewide Nontributary Ground Water Rules states in part that: <br />"The allowed average annual amount of withdrawal shall be based on an aquifer life of 100 years in <br />accordance with Section 37-90-137(4) (b) (I), C.R.S. The allowed average annual amount of <br />withdrawal for all of the wells on the overlying land shall not exceed one percent of the total amount <br />of water, exclusive of artificial recharge, recoverable from a specific aquifer beneath the overlying <br />land. " <br />Rule 8 (B) of the Statewide Nontributary Ground Water Rules states that: <br />"The total amount of water recoverable from a specific aquifer from a well or wells shall be determined <br />by multiplying the number of acres of overlying land as adjusted by Rule 8.C., if necessary, by the <br />average number of feet of saturated aquifer materials in the aquifer underlying those lands by the <br />average specific yield of those saturated aquifer materials. The allowed average annual amount of <br />withdrawal shall be 1% of the total recoverable water. In the case of aquifers to which the above <br />formula does not apply, e.g., fractured formations, the total amount of water recoverable shall be <br />determined in accordance with an appropriate methodology, as determined by the State Engineer. " <br />The computation for the Cash Mine Borehole of the total amount of water recoverable is as follows: <br />Recoverable Volume (AFY) = area of land [acres] <br />x depth of saturated materials [feet] <br />x specific yield of aquifer materials [cubic feet/cubic foot] <br />1. Area of Land. The area of land owned and controlled by MRV is 480 acres (Attachment 1). <br />2. Depth of Saturated Materials. The depth of saturated materials available for desaturation is <br />significant; there is no known limit to the depth of rock in. this area that can produce water. <br />However, for the purposes of this computation, the depth of saturated material that has been <br />demonstrated by the depth of the Cash Mine will be used (water has been observed to enter the <br />mine down to the lowest level). Level 9 of the mine was developed down to elevation 7382 ft <br />msl, 668 feet below ground surface at the mine collar. The depth to the top of the zone of <br />saturation was not measured prior to mine development, but in monitoring wells completed in <br />bedrock approximately 1,000 feet uphill from the mine the depth to water has averaged 30 feet in <br />the period 1985-2007. The pre-mining depth to water at the mine location would likely have <br />21 "The Rules and Regulations Applying to Applications For Wel I Permits to Withdraw Ground Water Pursuant to Section 37-90-137(4), <br />C.R.S.", Colorado State Engineer's Office, Colorado Department of Natural Resources, Division of Water Resources, January 24, 1986. <br />1601A-20070125 14