2010-08-13_REVISION - C1981038 - Laserfiche WebLink

Home Browse Search

Dudash August 13, 2010 Page 2 As indicated in the revised application two of these bedrock groundwater wells will be transferred to the Bowie No. 2 permit. In BRL's responses to our adequacy review for PR -12 at Bowie No. 2 they indicated that five potential monitoring wells (including the two proposed for transfer) are not appropriately constructed to monitor the B -Seam or the saturated zone above the B-Seam. This was confirmed in our meeting on July 28` regarding Bowie 1 & 2 groundwater with BRL representatives, Jim Stover, and me. I requested the well completion information for the wells that are identified by Jim Stover in his response to item 51 of PR -12. All of these wells listed in Table 4B (except DH -62 which I have no information about) have poor completions and are perforated at multiple intervals in the same borehole. Jim Stover did not provide any water quality data from these wells or information on when they were sampled during our meeting, but indicated that he may be able to retrieve water quality information. So, I am a little confused about whether or not good reliable baseline data exists for the deep bedrock groundwater wells (which is pertinent to how we move forward with the Bowie No. 2 Mine Plan with PR -12). In summary, the operator has been relieved from bedrock groundwater monitoring at Bowie No. 1 through previous revisions. There appears to he adequate information for shallow colIuvial and alluvial wells. On Table 4B in the PR -4 application twelve (12) alluvial /colluvial wells are indicated as still being monitored presently and I assume they will continue to be part of the approved monitoring plan for Bowie No. 1. I believe the deep bedrock groundwater description and associated baseline data discussion needs to be clarified and I have the following comments. 1. Under Groundwater Monitoring -Bowie No. 1 Mine and West Mine Site on page 114, the first sentence should be clarified. BRL states that "The Bowie No. 1 Mine East and West Mines are located several hundred feet above the water table of the area." This is not consistent with our understanding of the groundwater regime of this area. From this description it seems that BRL is describing the deep bedrock groundwater, but deep bedrock groundwater is not typically associated with a "water table" and no further description is given. If groundwater is confined by overlying impermeable rock formations (which I think is the case with the deep bedrock groundwater in this area) the well water levels that rise in the well represent a pressure level and not a water table. Bowie No. 2 has recently prepared a potentiometric map (Map 10 -B, B -Seam Potentiometric Surface Map) of which a portion overlaps this area in question. The water levels are shown to be deeper than several hundred feet. Please clarify what is meant by "water table of the area" on page 114 and provide descriptions of the occurrence of deep bedrock groundwater and the shallow alluvial and colluvial groundwater for inclusion into the application. This needs to be better characterized so that what we can transfer this information to the Bowie No. 2 Mine and have a better understanding of what baseline information is available and what additional data may be necessary. 2. Under Past Groundwater Monitorin�rmit and Adjacent Areas on pages 120 and 121 a discussion of bedrock groundwater monitoring is provided. BRL initially states that