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<br />Santa Fe is an extremely heterogeneous aquifer. Therefore, based on values <br />obtained from the published literature, it is possible that the longitudinal and <br />transverse dispersivities in the Santa Fe aquifer are actually greater than those <br />estimated in the Technical Revision No. 8 Phase II submittal. BA1R believes that, <br />given the range of values in the literature for similar material, these longitudinal <br />and transverse dispersivity values are appropriate and representative. <br />However, even if the dispersivity values are reduced to the low end of reasonable <br />values (longitudinal = 30 feet, transverse = 10 feet) the effectiveness of the <br />existing monitoring wells to detect contaminants is unchanged (See sensitivity <br />analysis results). <br />3. Using the factors available fran the report, the Division: cannot corrfrnn dre <br />estimates made in the report of the extent of the dispersion of arty contaminant <br />leaking from the collection pond and tailings facility. The Division Believes there <br />is potential for evidence of a leak, e.g. from the collection pond, tp Bypass Well <br />M-9. <br />17re operator should supply calculatioru and plots of contaminarr! plumes thnt <br />support their apparent conclusion drat detectable and timely evidence of drese <br />plumes would be observed in the existing monitoring wells. <br />~ Evidence was provided that the water in the Santa Fe aquifer sampled rhu•ing the <br />testing of the monitoring wells did not contain cyanide, at least above detection ~ <br />limits. No other means of evaluating how representative these samples were tf <br />the Santa Fe aquifer were provided; nldrougl: it is the usual pracdcc to at lens! <br />~ ~ record freld parameters for such samples. <br />RESPONSE: BMR believes that the geologic and geolrydrologic data base (i.e. moisture <br />j content testing that shows the unsaturated soils to be well below specific <br />,' retention, the low permeability of these soils and the lenticular nature of the Santa <br />Fe which would tend to favor lateral flow over vertical flow) supports the <br />contention that it is extremely unlikely that leakage from the collection pond <br />and/or tailings facility would result in detectable cyanide concentrations reaching <br />the aquifer. <br />If BMR assumes that detectable concentrations of cyanide would eater the Santa <br />Fe aquifer from a hypothetical leak, then BMR disagrees with the Division's <br />comment that well M-9 would not detect a leak from the collection pond (see <br />sensitivity analysis results). <br /> <br />-5- <br />