2015-03-23_REPORT - M1977424 - Laserfiche WebLink

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Logan Wash Mine Annual Report Permit No. M- 1977 -424 3.3 Research Mine Manometer Monitoring 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 level begins to subside; the manometer is monitored monthly at all other times as access allows. If manometer measurements were to indicate a very high (> 36 inches) reading for more than a week's time, the water in the mine can be released and sampled. The manometer level recorded during 2014 ranged from 0 inches to a high of 9 inches. 3.4 Evaporation Pond Leak Detection System 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 5 shows the pressure transducer water depth results for the period October, 2011 to February, 2015. During the reporting period, the pressure transducer log indicated that the Leak Detection Vault received water and was automatically pumped down beginning in March, 2014 and continuing intermittently until mid- October, 2014. Based on observations of suspended buckets under the three collection pipes, it appeared water had entered the vault through the east drainage pipe. In early August, 2014 water level in the Detection Vault rose due to failure of the solar system's batteries. The batteries were replaced and the automated pump system resumed normal operations. Periodic inspections of the liner did not reveal any new open holes, cuts or cracks near the water line. 4.0 Reclamation Activities in 2014 Reclamation activities conducted at the Logan Wash Mine in 2014 are discussed in the following sections. 4.1 Revegetation Maintenance During the reporting period, the irrigation system installed for planted saplings on the Upper and Lower Mine Dumps was not deployed. It is anticipated that irrigation system will not be used in the future. No other revegetation work (weed removal or mowing) was conducted. 4.2 Well Abandonment No monitoring wells were abandoned during the reporting period. 4.3 Daylight Bench Slope Stability Monitoring The Daylight Bench was constructed to support sealing of the Daylight Portal in 2004. Tension cracks and minor subsidence was first observed in 2009 on the small bench. The contractor Geo- Smith Engineering has continued to survey the Daylight Bench for slope movement since May, 2011 and continued through 2014 during the spring and summer quarters, access permitting. Surveys in 2014 were conducted on May 2 "d, June 13`x' and October 17`x'. Prior to the October, 2013 survey, no significant movement of the survey monuments was observed. The October 2013 survey noted that 2 of 6 extension stakes have shown minor to small Western Water & Land, Inc.