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PERMIT #: M-1980-244 <br />INSPECTOR’S INITIALS: AME <br />INSPECTION DATE: August 12, 2015 <br /> <br /> <br />Page 4 of 15 <br />the cone of depression surrounding the HVSCS pumps in the pregnant solution storage area (PSSA). Because of <br />this, the piezo (pipe) reading should, theoretically, always read higher than the pumps at least while pumping is <br />occurring. After reviewing water level readings recorded by the Division from 12/26/2011 to the current <br />inspection, it appears that this has been the case, except for in November and December of 2014, when one of <br />the pumps was reading 0.7 feet higher than the piezo (pipe) reading. The Division understands that the primary <br />concern regarding AGVLF water level readings is that they do not exceed their respective values (in feet) for <br />80% storage capacity. Therefore, if a pond piezometer transducer is reading levels lower than its respective 80% <br />value, this is not a significant issue unless it is shown that the values are inaccurate. <br /> <br />To help prove that the constant transducer readings for the piezo (pipe) are accurate, the operator agreed to <br />obtain a manual water level reading from the piezo (pipe) during the inspection. The inspector, accompanied by <br />Mr. Campbell, observed while mine staff used a water level indicator tape calibrated to 1/10 of a foot to <br />measure the depth to water from the top of the casing (Photo 5). The mine staff obtained a depth to water <br />reading of 25.8 feet. Mr. Campbell indicated he believed the total length of the piezo (pipe) to be approximately <br />60 feet. However, he was uncertain of the elevation (depth) of the transducer in relation to the top of casing. <br />Supposing that the piezo (pipe) is 60 feet in length, and knowing that the depth to water from top of casing is <br />25.8 feet (as measured), if the transducer was at the very bottom of the piezo (pipe), then it should be reading <br />34.2 feet (submergence depth), rather than 30.9 feet as recorded. However, to determine the expected transducer <br />reading, one would need to know the elevation (or hanging depth) of the transducer. Since the measured depth <br />to water was 25.8 feet, the transducer reading of 30.9 feet would only be accurate if the transducer is located a <br />minimum of 3.3 feet from the bottom of the casing (at 60 feet total length). <br /> <br />For comparison, mine staff also obtained a manual water level reading from Phase II & III HVSCS pump #5 <br />(Photo 6). The depth to water reading for this well was 34.9 feet. The transducer reading recorded for this pump <br />within 30 minutes beforehand was 22.8 feet. Once again, if the total length of the well is 60 feet, and the depth <br />to water from the top of casing is measured at 34.9 feet, then one would expect the transducer to read 25.1 feet, <br />unless the hanging depth of the transducer puts it 2.3 feet above the bottom of the casing. <br /> <br />After the inspection, Mr. Campbell provided the Division with calibration sheets for the wells and piezometers <br />associated with all AGVLF phases. These sheets give the elevation for the top of casing and for the pond <br />bottom for each well and piezometer. With this information, one can determine water levels by measuring depth <br />to water from the top of casing, and subtracting that value from the difference between elevations. The <br />elevations for where the wells and piezometers terminate above the pond bottom or for where the transducers <br />are suspended in the casing are not given; however, this information is not needed if measurements of depth to <br />water from top of casing are obtained. In the case of the Phase II & III pond piezometer, the calibration sheet <br />gives an elevation difference of 56.8 feet from top of casing to pond bottom. As stated above, the depth to water <br />measurement obtained during the inspection was 25.8 feet. Subtracting these values gives a water level of 31 <br />feet, which is consistent with the transducer reading of 30.9 feet. Additionally, the calibration sheet gives an <br />elevation difference of 58.2 feet for Phase II & III pump #5. The depth to water measurement from this well <br />was 34.9 feet. Subtracting these values gives a water level of 23.3 feet, which is 0.5 feet higher than the value of <br />22.8 feet that was recorded from the transducer. The Division believes this is a reasonable difference in values <br />as the transducer readings for the HVSCS wells tend to fluctuate by a few feet, sometimes more, in response to <br />pumping in the PSSA. <br /> <br />Recorded Water Level Readings: <br />The inspector, accompanied by Mr. Campbell, recorded water level readings from the transducers for AGVLF <br />HVSCS and low volume solution collection system (LVSCS) from Phase I, Phase II & III, and Phase IV. <br />Readings were also recorded for the external pond LVSCS. Readings were not obtained from Phase V, the <br />underdrain discharge area, or the well pumpback system during this inspection. The recording sheet for values