2010-02-09_REPORT - M1977424 - Laserfiche WebLink

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WWL Western Water & Land, In February 9, 2010 COVED MAR U ? 2010 oiyis n of Reclamation, fininn and Safety Colorado Division of Reclamation, Mining and RECEIVED Mr. Travis Marshall 0 ? FEB 9 2010 GRAND JUICTiO.Na t:iELD OFFICE DIViB&GN OF RECLAWTION iVII LING & SAFETY 101 South 3rd Street Suite 301 Grand Junction, CO 81501 RE: Logan Wash Mine (M-77-424) Evaporation Pond Leak Detection Dear Mr. Marshall: Western Water & Land, Inc. (WWL), consultant for Occidental Oil Shale, Inc. (OOSI), has prepared this letter as a formal notification of a possible leak in the liner at the Logan Wash Mine Evaporation Pond (permit no. M-77-424). This letter follows my initial verbal notification to you on the morning of February 5, 2010. The mine discharges retort water to the evaporation pond at a rate of approximately 2.5 gallons per minute through a 6-mile long 4-inch PVC pipe line buried along Logan Wash Road. The 4-acre, HDPE-lined evaporation pond stores and evaporates retort mine water that is discharged from the Logan Wash Mine. The pond was constructed in 1984 and was incorporated into the mine permit in 2006. The evaporation pond is not officially permitted by the Colorado Department of Public Health and Environment (CDPHE) because it is a non-discharging facility. However, CDPHE did have input on its design after OOSI initially contacted them prior to construction. The pond contains a PVC-pipe leak detection system under an 80-mil HDPE liner. The head on the pond typically varies from 0 to approximately 1 foot with several feet of freeboard. The leak detection system was designed to capture leak water and discharge it through 3 main 2-inch PVC header pipes to the leak detection vault. Cross- cut gravel drains intersect the 3 header pipes. The water quality of the retort water is a sodium sulfate type. The water is characterized by high total dissolved solids (TDS) (5,000 to 7,000 mg/L), with contributing constituents primarily being sodium (1,350 mg/L), potassium (950 mg/L), sulfate (4,000 mg/L), and bicarbonate (450 mg/L). Chloride is present in concentrations of approximately 85 mg/L. The most recent biannual sampling of the retort water was conducted in November 2009 near the sealed mine portal. The analytical results of this sample showed a Total Petroleum Hydrocarbon (TPH) concentration of 7.6 mg/L. BTEX was detected in small concentrations; benzene was reported at the highest concentration (4.3 µg/L). The evaporation pond water is expected to be more concentrated as a result of evaporation, but varies depending on seasonal discharge rate and precipitation. The pond water has not been sampled in recent years. The settling pond, a small 100 mil HDPE-lined pond that holds water prior to discharge into the evaporation pond, was sampled in November 2009. These data show that the water quality is similar to Applications in Earth Science 743 Horizon Court Suite 330, Grand Junction, CO 81506 Phone: (970) 242-0170 Fax: (970) 242-0270