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i <br />Mathews, Routten <br />Page 3 <br />January 7, 1999 <br />Given the available information, it is difficult to Wile out various explanations for the source of the <br />increasing head inwell E-1. Potential sources for the rising water include: recharge from the glacial <br />alluvial aquifer, inflow from the E Sean mine workings, and possibly inliltration from an irrigation <br />ditch that is located approximately 10 yards from the location of E-1. Infiltration from the irrigation <br />ditch is unlikely, but could occur if there is no surface casing a[ E-1 or if the surface casing is <br />damaged. <br />We should have the operator assess the source of the water so that we can make a determination of <br />whether or not the conclusions presented in the PAP are still valid at this time. In summary, the <br />PAP states that discharge from the portals will not occur and that the glacial/alluvial aquifer will <br />receive all or most of the post-mining discharge. <br />Hydrologic and water quality conditions have not been addressed in the PAP in the event of apost- <br />mining discharge from the mine portals. There is no mitigation plan or proposed reclamation <br />activities addressinga perpetual discharge situation. If the rising water level in well E-1 is not the <br />result of recharge from the alluvial aquifer, then it seems likely that the potential exists for mine <br />water discharge from the E-Seam portals. Thus, the operator should address the possibility of mine <br />water discharge from the portals and provide a contingency plan to mitigate any potential impacts. <br />The contingency plan should include information such as estimated worse case dischazge volumes, <br />anticipated water quality, handling and dischazge of water, and treatment options (if deemed <br />appropriate). <br />If the PAP predictions are correct in stating that the glacial/alluvial aquifer will receive all or most <br />of the post-mining discharge, [hen how will this impact down gradient groundwater and surface <br />water users? The PAP states that effects of mining activities on groundwater and surface water will <br />be minimal. With respect to groundwater, the PAP indicates that all residents in the area use <br />domestic water from the Colby Water System which has a separate aquifer not affected by the <br />proposed mining activities. <br />The Kaman Tempo report indicates that post-mining water quality might be much worse than the <br />water quality of undisturbed strata. The concern is what effect this water might have if it moved into <br />the glacial/alluvial aquifer and then into Ward Creek. The Ward Creek valley does meet the criteria <br />for alluvial valley floors (AVFs). The report presents mass balance calculations and shows that <br />Wazd Creek (under worse case conditions) would have a TDS of 698 mg/I and an SAR of 4. These <br />predicted worse case levels exceed material damage suspect levels according to our MLRD material <br />damage guidance document. Our guidance document indicates that when SAR's above 3 are <br />expected to result from mining, it would be incumbent on the applicant to conduct appropriate tests <br />to demonstrate that significant production losses would not result. The value of 698 mg/I TDS <br />exceeds the suspect level for crops of 500 mg/I. However, our guidance document was not written <br />until January ] 988 and the PHC predictions in [he Kaman Tempo report were published in 1982. <br />Additionally, there aze salinity and suspended solids standazds for surface water in the Colorado <br />