2014-05-28_REVISION - C1996083 - Laserfiche WebLink

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William A. Bear Page 4 of 8 May 28, 2014 It is unclear how the requirements of Rule 4.05 will be adhered to without down gradient monitoring of groundwater. Rule 4.05.13(3)(b) requires that monitoring of groundwater continues until after cessation and use of underground mine workings and until it is demonstrated that the operation has minimized disturbance to the hydrologic balance in the permit and adjacent areas. Ground water monitoring will be required throughout the bond liability period. The notes and comments in Table 1 paint a gloomy picture of the efficacy of the water monitoring program currently in operation at the Bowie 2 mine. Of the 6 groundwater monitoring points currently active, only one is returning reliable data (2010 -113). Of the remainder: three show pH values that at least partially invalidate the remaining water quality data and render the static water level values questionable, since the quality of the seal above and below the screened interval is in doubt (2010 -1SS, TC- 03 -01(B) and TC- 03 -02); and two provide no data, with the comment only that "the depth to water probe only goes down the hole part [way] and gets gummed up with grey mud ", (CWI -DH -58 and CWI - DH-60). Table 1: Completion Summary GW monitoring point Notes (based on information from Vol. III, Ex. 3 of the PAP), and comments CWI -DH -58 Old well. Originally part of Bowie 1 permit, incorporated with PR -12. Completion information is not reliable. Assume 2" PVC perforated at 8 separate 20' intervals, including upper B -seam. Monitored quarterly by BRL since 8/2010. No monitoring data has been reported CWI -DH -60 Old well. Originally part of Bowie 1 permit, incorporated with PR -12. Completion information is not reliable. Assume 2" PVC perforated at 7 separate 20' intervals, including upper B -seam. In 2010 the hole was cemented to the bottom of the upper B -seam, leaving a single perforated interval. Monitored quarterly by BRL since 8/2010. No monitoring data has been reported. TC -03 -02 10' X 2" steel screen in the sandstone above the upper B -seam. Completed in 2003 and monitored quarterly since 9/03. *Shown in different locations on Maps 9 & 1013* Monitoring data includes pH values in excess of 12 which indicates that the well has been contaminated with alkaline grout (Nielsen, 1991). Although the pH values have recently decreased (within a range of 7.7 - 9.1 since 2010) they are still both higher and more variable than would be expected, hence the remaining water quality data should be treated with caution. TC- 03 -01(B) 10' X 2" steel screen within a 9 7/8" hole. Screened casing is within a 45' section filled with sand which includes the upper B -seam. Below the screened interval the hole is plugged with cement, and above it is plugged with Bentonite pellets. Completed in 2003 and monitored quarterly since 9/03. Monitoring data consistently records pH values in excess of 12, indicating that the well has been contaminated with alkaline grout (Nielsen, 1991) and invalidating the remaining water quality data. (TC- 03 -01(R) shares the same hole and extends to the Rollins Sandstone. It has not been monitored since 11/2010, but has been left open) 2010 -1SS 10' X 1.5" steel screen within an 8.75" hole. Screened casing is within a 20' section filled with sand in the sandstone above the upper B -seam. Below the screened section the hole is plugged with cement, and above it is plugged with Bentonite pellets and then cement to the surface. Monitored quarterly since 11/11. Monitoring data consistently records pH values in excess of 12