1992-11-16_REVISION - M1988112 - Laserfiche WebLink

Home Browse Search

~ III IIIIIIIIIIIII III ~ 1 DIVISION OF .N IN ERALS AND GEOLOGY Department of Natural Resources ,'~-`O'^~ :~' c '~ 1317 Sherman 51.. Room 215 - , , Denver, CO 80.03 ~~a Phane:1J031 B66-756" FA?(: 17031 8J 28106 D?eve-:.ber 16, 1992 ~ `\~11^ .~:, . r~ a „n~ "'n ision ~u••i:or Mr. Andre J. Douchane Battle Mountain Gold Company 5670 Greenwood Plaza Blvd. Englewood, CO 80111 RE: San Luis (Permit M-88-112) Review of BMR Response to DMG Adequacy Review of TR-08 Dear Mr. Douchane: The Division is in the process of confirming, as part o$ its review, the modeling of containment plumes using the various input parameters employed by Battle Mountain's consultants. The Division's initial evaluation of the above referenced response, however, indicates certain questions exist in regard both to the makeup of the response as well as to its conclusions. These questions are indicated below. 1. BMG has provided sensitivity analyses of porosity and dispersivity in order to demonstrate the adequacy of the network which is appreciated. The single point of discharge utilized for both analyses, however, was the mid-point between Ftells M-12 and M-13 and identified as "a worst-case scenario". While this may be one such scenario, the one that concerns the Division more is a point of limited discharge from the southwest part of the collection pond, between Wells M-13 and M-9. 3MG should supply a plot of appropriate containment plumes originating from this area in order to more completely demonstrate the adequacy of the monitoring network. 2. BMG has indicated that Figure 1 presents the results of the porosity analysis and Figure 2 the dispersivity anelysis. The reverse appears true. In true Figure 1, the plot of a plume under the influence of 200 porosity appears to be the blue rather than red plot; the 35a porosity plot the red rather than blue. Fcr the record, BMG should submit a revised narrat;ve or at least acknowledge the errors. 3. Both sensitivity analyses employed constant contam~~nant source strengths of 2.5#/day and a period of 20 years. Tie reasons for these input parameters were, however, not explained in the response. BMG should explain its selection of the 2.5# source strength and 20 fear period of time employed in the sensitivity analyses.