2016-02-08_REVISION - C1996083 - Laserfiche WebLink

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2.04.7 Hydrology Description The monitoring data for well 2010-1 SS suggests that the well was initially contaminated during construction, but has since reached an equilibrium state from which future changes may be observed. For the period of record from March 2015 through October 2015 for 2010-1 SS, the average field conductivity was 1,384 umhos/cm with a range of 1,330 to 1,420 umhos/cm, the average field ph was 7.1 with a range of 7.0 to 7.2, average total iron was 3.35 mg/I with a range of 2.47 to 4.94 mg/I and average total manganese was 0.116 mg/I with a range of 0.095 to 0.145 mg/I. The data for well 2010-1 B suggests that the well was poorly constructed rendering the water quality data invalid. Eliminating the first two monitoring events from the historic data yields more consistent information with the high pH the most questionable data. In well 2010-1 B completed in the B -Seam, the average conductivity is 2,900 umhos/cm with a range of 2,400 to 3,900 umhos/cm, the average ph was 12.7 with a range of 12.5 to 12.9, average total iron was 0.32 mg/I with a range of 0.18 to 0.63 mg/I and average manganese was 0.02 mg/I with a range of <MDL to 0.02 mg/I for the period September 2012 to October 2013. After the 2014 well rehabilitation work, 2010-1 B had the following water quality: pH 9.75 su, conductivity 277 umhos/cm, total iron 4.31 mg/I, manganese 0.0621 mg/I. For the period of record from October 2014 through October 2015 for 2010-113, the average field conductivity was 761 umhos/cm with a range of 378 to 1,070 umhos/cm, the average field ph was 10.0 with a range of 9.8 to 10.2, average total iron was 2.53 mg/I with a range of 1.41 to 4.31 mg/I and average total manganese was 0.0399 mg/I with a range of 0.0259 to 0.0621 mg/I. The PR -13 mine plan areas, west of Terror Creek, has up gradient and down gradient monitoring wells. CWI-DH-58 and CWI-DH-60 are up gradient monitoring wells and 2010-1 B and 2010-1 SS are down gradient monitoring wells. See Map 9 for well locations. Monitoring well CWI-DH-58 was replaced with CWI-DH-58A at the end on 2014. Wells 2010-1 SS and 2010-1 B will be down gradient monitoring wells for the PR -14 (Spruce Stomp) mining area. The wells will be mined through late in 2016 based on current mine plan timing. The Operator does not intend to construct down gradient points of compliance. Rule 4.05.13(1)(b)(ii) provides considerations to be used in establishing points of compliance. One consideration is protection of human health and environment. It is highly unlikely the public will use the deep bedrock groundwater located north of the Bowie No. 2 Mine west mine workings (west of Terror Creek). It is simply too expensive to install a domestic or livestock well at such extreme depths. A second consideration is for vertical migration of contamination. The water level in the 2010-1 B and 2010-1 SS indicates the water in the B -Seam and sandstone only rise to a level of 100 -feet and 30 -feet above their respective formations which would limit vertical migration to those distances. Vertical migration would also be limited by interbedded shale and sandstone layers. A third consideration is the nature of the contaminants present. The deep waters above TR -99 2.04-36- 02/15