2012-01-27_HYDROLOGY - M1977424 - Laserfiche WebLink

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Dear Travis: Western Water & Land, Inc. RECEIVED Western Water & Land, Inc. (WWL), as agent for Occidental Oil Shale, Inc. (OOSI), has prepared this letter to inform you of recent activity regarding the leak detection system at the Logan Wash Mine Evaporation Pond (Permit M -1977 -424). January 26, 2012 Mr. Travis Marshall JAN (/ 7 2012 Environmental Protection Specialist GRAND JUNG i v HELD OFFICE Division of Reclamation, Mining and Safety DIVISION OF 101 South 3'�, Suite 301 RECLAMATION MINING d SAFETY Grand Junction, CO 81501 RE: Permit M- 1977 -424, Logan Wash Mine Evaporation Pond Leak Detection Activity WWL monitors the pond frequently (weekly to twice per month) during the spring months (generally March through June). After seasonal peak flows at the mine (usually May - June), monitoring is conducted monthly. However, monitoring schedules also vary with road conditions. Access to the pond is questionable during winter months (November — February) due to mud or snow or after summer precipitation due to extremely muddy road conditions. The data logging transducer installed in the sump is downloaded quarterly. Observations collected at the leak detection system vault include presence or absence of discharge from the three PVC leak detection pipes that discharge into the sump; the general depth of water in the sump, evidence of leakage into the vault from precipitation, evidence of staining on the liner from the sump pump pipe discharge; and voltage in the solar- powered batteries. Photographs of the vault/sump are taken during each inspection. In addition, the pond liner perimeter is inspected. Data downloaded from the pressure transducer on January 12, 2012 (including data for the 4 quarter 2011), revealed that the water levels in the,sump had fluctuated from apparent pump cycling. Beginning on December 14, 2011, two days after an inspection of the vault and pond, the data indicate that the sump began taking on water and the automated pump began cycling on and off until December 28 The pump cycled on 10 times between December 14 and 28 but the first nine cycles occurred between the 14 and 20 Figure 1 shows the results of the transducer data from December 2009 to January 12, 2012. II IL Division cat Inspections of the vault 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. Transducer data for the period January 12 to January 24 do not show any indications of water level fluctuations from pump cycling. On January 24, an inspection of the pond liner near the water line did not reveal any holes, cuts, or parted welds. A significant precipitation event occurred in the area on December 13, as evidenced by measurements at the Altenbern meteorological station located several miles to the north of the pond. A total of 0.28 inches of precipitation was recorded on that day with 5 inches of snow. One hypothesis is Applications in Earth Science 743 Horizon Court Suite 330, Grand Junction, CO 81506 Phone: (970) 242 -0170 Fax: (970) 242 -0270