2012-03-27_REPORT - M1977424 - Laserfiche WebLink

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Outfall 002 (Research Mine discharge) is to be monitored monthly for pH, TSS, oil and grease, arsenic, copper, cyanide (WAD), lead, molybdenum, selenium, uranium, boron, and chloride; and quarterly for TDS, mercury, and WET. Continuous flow monitoring is required at both outfalls, but because Outfall 002 is shut -in and has not discharged for many years, no flow monitoring or sampling has occurred under the new NPDES permit. For more information regarding the Research Mine portal closure and management of the Research Mine drainage see Technical Revision (TR) No. 4 and TR No. 6 which present significant revisions to Exhibit E, the Reclamation Plan for Logan Wash Mine. 3.2 Mine - Water and Retort - Water Discharge Discharge measurements of clean (non- retort) mine -water discharge (Outfall 001) and retort- water discharge were conducted on a quarterly or more frequent basis when access and schedule allowed. Continuous flow (meter) monitoring of Outfall 001 water came on line in August 2011. These data were collected by OOSI to assess and evaluate mine closure effectiveness, to support operation and maintenance of the Evaporation Pond, and future water management options. Sampling of retort mine drainage water and mine water (Outfall 001) was conducted in May and October 2011 to evaluate retort water quality with time in support of eventual mine closure. The samples were collected from the retort drainage pipeline inside the Lower Bench Vault. The analytical results for samples collected during the reporting period do not indicate a significant improvement of retort water quality compared to past sampling events. 3.3 Research Mine Manometer Monitoring 3.4 Evaporation Pond Leak Detection System Logan Wash Mine Annual Report Permit No.: M- 1977 -424 The manometer installed in the Research Mine Vault is monitored and recorded on a weekly basis in the spring months of April and May, or until the peak reading begins to subside; the manometer is monitored at least quarterly at all other times. If manometer measurements were to indicate a very high (2 36 inches) reading for more than a week's time, the water in the mine can be released and sampled according to the NPDES schedule. The manometer level recorded during 2011 ranged from 0 to a high of 18 1 /4 inches. Monitoring of the Evaporation Pond Leak Detection vault is conducted by continuous measurement of water pressure (depth) in the vault sump using an installed pressure transducer. On -site monitoring is conducted twice monthly as access conditions allow. Figure 4 shows the pressure transducer water depth results for the period January 2011 to January 2012. Until mid - December 2011, the pressure transducer data indicated and supported observations that no water was entering the vault through the leak detection system. However, data indicated that the sump began taking on water and the automated pump cycled 10 times between December 14 and 28 Inspections on December 12 and January 12, 2012 showed no water emanating from the three leak detection pipes and no unusual water levels in the sump. An inspection of the pond liner near the water line did not reveal any holes, cuts, or parted welds. One hypothesis to explain the pump cycling is that it was related in some way to a large precipitation event on December 13 In addition, normal inspections of the liner revealed an open cut in the liner in the northwest corner just above the existing waterline at the base of the slope of the pond. It was apparent that the cut was associated with a cement cinder block that had been placed, possibly carelessly, to Western Water & Land, Inc. 5