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i ;.- <br />Steve Renner 3 <br />alone for the purposes of a bond release. It is my understanding that the <br />Department of Mining and Geology (DMG) believes that reviewing cover <br />determinations on smaller acreages will not be statistically valid unless the areas <br />are combined to reach an acceptable confidence level. AFO does not concur with <br />the use of combining transects on disjunct areas. Eastern mining operations <br />routinely consist of acreages of less than five (5) acres which also must be <br />evaluated utilizing sampling techniques that use a 90 percent statistical confidence <br />interval. If you would like to discuss sampling methodologies, please contact <br />Dennis Byrnes of our office. <br />Another concern relates to the requirement found at CCMR 3.03.1(3)(b). Phase I!. <br />can not be approved if contributions of suspended solids are in excess of pre- <br />mining levels as determined by baseline data or in excess of levels determined on <br />adjacent non-mined land. In this instance, the operator submitted data <br />documenting sediment loads in the sediment ponds. However, there is no <br />indication in the data or DMG's proposed decision document as to the premining <br />level which the operator can not exceed or how that level may have been <br />determined. DMG will have to make a determination as to the premining <br />suspended solids level prior to making a Finding that the permittee has met the <br />requirement of 3.03.1(3)(b). <br />In addition to these concerns regarding the Phase II release, AFO would point out <br />that the decision document for Phase I bond release specifically excluded from the <br />release " ` ' 'two minor slide areas at Northern No. 1 and all monitoring wells and <br />drill holes." Those should be addressed prior to any subsequent Phase II release <br />request. <br />If you have further questions regarding this correspondence, please call <br />Stephen G. Rathbun at (505) 766-1486. <br />Sincerely. <br />