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J. Given the lack of adequate ground water monitoring well data in Poverty Gulch (North <br />Cresson Mine), with the exception of PGMW-2 which has been dry since construction in <br />2001, the Division requests at least two more additional wells be drilled and completed <br />prior to initiating impacts in the area. The Division allowed the current monitoring with <br />limited data to be in place, since the plugging of the two monitoring wells (PGMW-1A <br />&1B), because there are no current active Cresson Project disturbances in the area and none <br />were proposed under Amendment # 8. The current mining plan proposes to disturb a <br />considerable amount of acres as part of the mine life extension. Even though there is a lack <br />of measurable drainage, except in association with a heavy precipitation event, and a few <br />wet areas down gradient, which may or may not get shallow ground water flow from <br />upgardient areas, there is still the potential for some adverse effect to the overall hydrologic <br />balance. That is why the Division recommended to CC&V, in the reclamation and mining <br />portions to completely backfill the mine pits in the area to original contour, instead of the <br />current partial backfill proposal. Please provide a location for the additional ground water <br />monitoring wells for these areas as part of your response to the adequacy. The DRMS <br />would like CC&V to collect as much quarterly data as possible prior to affecting acres in the <br />area. <br />K. The Grassy Valley water balance modeling utilized the Gold Sim ( version9.60), the same <br />program used to model the water balance for the valley leach facility. This is a graphical <br />program that is supposed to determine the dynamic deterministic or stochastic <br />simulations. The Division is not even certain this modeling program can accurately predict <br />when a solution placed in a portions of a lined pad will report to the pregnant solution let <br />alone predict long term water balance for an open natural system with changing mining <br />and backfilling activities. What the Division would like to see are the modules for the <br />program so we can understand the inputs used to get the water balance and if it indeed <br />mimics site specific conditions. <br />L. The long term characterization of the water quality devotes great detail to the impact of <br />sulfide oxidation. What about sulfate salts that may exist on surfaces of already oxidized <br />material and are more readily flushed and mobilized than are the products of more <br />refectory sulfides that are present in the un-oxidized material? Please comment on this in <br />terms of how much of this material might be present and what effect it might have on water <br />quality? <br />M. Vol. II PG. 15 states that sulfate and zinc releases will not result in loading increases as <br />calculated, because of factors such as the slow transport of the constituents and water <br />sequestration. This reasoning is not entirely clear and requires further explanation. <br />Additionally, this analysis begs the question that after the plug of newly released sulfate <br />and zinc have been migrating downward for some years, is it reasonable to assume that the <br />condition of chemical steady state can be attained through the vertical section of the <br />diaterem in which those calculated concentrations (22,000 mg/1 for sulfate, and 159 mg/1 <br />for zinc) may actually be sustained? <br />N. A statement is made that the alkalinity has leveled off in the Carlton Tunnel Discharge. In <br />fact, the three highest alkalinity values ever measured have been collected in the past 5 <br />sampling events shown on Figure 18, suggesting the alkalinity values are on the rise again. <br />It may be beneficial from a modeling standpoint to quantify why alkalinity has been <br />increasing in recent years. If future overburden leachate turns out not to be as predicted, <br />11