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the pads and fill in the gaps, but initially it may be beneficial to spread topsoil in this <br />area and seed with native grasses to help stabilize the areas between the pads. <br />CC&V Response: <br />Areas between the transplanted aspen pads will receive growth medium and will be <br />seeded with the CC&V reclamation seed mix to establish a wildlife/grazing land use and <br />ground cover while the aspen spread from the transplanted "pads" over a period of years. <br />DRMS Question to CC&V Adequacy Response (David Bird): <br />VI. A.: On the contrary, it is misleading to state that the system will behave as a large homogenous batch <br />reactor with unli i-in and unlimited acid-neutralizing capacity. Historical i» forlnulion indicating hox- <br />rapidly the Carlton Tunnel drained the system after its completion suggests that the ground water flow in <br />the system is fracture controlled (Eary et al., 2003). Thus it is possible that the flow along these fractures <br />over the past 60+ years could have preferentially depleted the acid-neutralizing mineral.,. Therefore, the <br />probability that igfiltraling leachate.fi•om the waste rock will even cone into contact with acid- <br />neutralizing minerals that are not along fractures inay be progressively decreasing. <br />Available estimates ofground water travel times range from at least 25 yearsfor travel front the level <br />equivalent to the Roosevelt Tunnel clown to the Carlton Tunnel (Eary et al., 2003, based on W <br />concentrations) to 50-100 years, for travel from ground sta fiace to The Carlton Tunnel (MLE Project <br />Application). If these estimates are correct, then there is a high probability that the leachate front the <br />first waste rock placed at the mine back in the 1970's when open pit mining first started has not yet even <br />reported to the Carlton Tunnel. Therefore, assertions that the diatreme carbonates are successfully <br />neutralizing the acidic waste rock leachate are inere speculation, and it remains to be seen how the <br />.system will respond geochemically to the infiltration gfthe waste rock leachate and the ensuing water <br />quality at the Carlton Tunnel. Based on the aforementioned, it is risky to assume that the Carlton Tunnel <br />discharge will continue with the same water quality that existed prior to inception of surface mining. <br />Prior to surface inining, there were not the volumes of waste rock accumulated on the ground surface as <br />there are now. <br />The Division accepts the Operator's rationale.for not providing detailed spatial and temporal ABA data <br />during waste rock placement. However, this does not preclude the Operato'fi-oin de'taile'd nonitoring of <br />waste rock. ABA during and after placement. Considering the ground water travel time's that are <br />estimated in terms of decades for infiltration to report to the Carlton Tunnel, a long term monitoring <br />program after closure and before reclamation re'le'ase might be necessary. <br />CC&V Response: <br />CC&V agrees with DRM5 that the diatremal groundwater flow system is not <br />homogeneous. The data record, both of investigations into the physical and chemical <br />nature of the rockmass and evaluations of the quality of the regional ground water that <br />exits the diatreme through the Carlton Tunnel, are consistent with the diatremal <br />rockmass behaving as a large, inhomogeneous batch reactor. The principal <br />inhomogeneities include variations with depth and on an areal basis of the carbonate <br />content of the rockmass; and porosity, fractures, faults, and mined openings within the <br />rockmass providing inhomogeneous flow paths. <br />The historical data on the flow after completion of the Carlton Tunnel indicates that the <br />flow was relatively slow, and that the diatreme is porous. The Carlton Tunnel required <br />approximately 25 years to drain the regional ground water table from the Roosevelt <br />Tunnel elevation (8,000 ft msl) to the Carlton elevation (-7,000 ft msl),with most of the <br />drainage occurring in the first 14 years (1941-1954). Based on historical records, the <br />total flow in excess of the steady flow of approximately 1,600 gpm that exited the <br />Carlton Tunnel in that time was approximately 80 billion gallons. At the elevations <br />between these tunnel levels, the area of the three diatremal lobes together is 92 million <br />square feet (3.3 square miles, or about half the diatremal outcrop area). Dividing the