2016-02-08_REVISION - C1996083 - Laserfiche WebLink

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2.04.7 Hydrology Description CWI-DH-58A and CWI-DH-60, are up gradient monitoring wells for the west mining district. Completion diagrams for the two wells are included in Volume III, Exhibit 3. CWI-DH-60 was perforated at six different intervals with the top perforation being the upper B -Seam. The well was monitored for depth to water from July 21, 1983 until October 04, 1990. Generally the water depth was about 1,000 feet which is slightly above the upper B -Seam. One mixed aquifer water quality sample was obtained on August 22, 1983. Conductivity was 7,560 umhos/cm, ph was not available, total iron was 0.58 mg/I and manganese was 0.09 mg/l. The Applicant cemented CDW-DH-60 from the bottom of the well to the bottom of the B -Seam in September 2010. Based on monitoring after the cement job, the B -Seam is dry at this location. Beginning in 2011 the field technician has not been able to get monitoring equipment down to the water level. Monitoring well CWI-DH-60 was cleaned and rehabilitated between August 20 and August 23, 2014. On August 22, 2014, the well was evacuated using the airlift and bailing techniques and the water quality showed a pH of 7.70 s.u., conductivity of 863 pS/cm, and temperature of 20.5° C. After a 12 hour recovery period, the SWL was measured at 892.0 feet btoc (August 23, 2014). For the period of record from October 2014 through October 2015 for CWI-DH-60, the average field conductivity was 9,500 umhos/cm with a range of 8,500 to 10,000 umhos/cm, the average field ph was 8.3 with a range of 8.1 to 8.4, average total iron was 3.12 mg/I with a range of 1.47 to 3.73 mg/I and average total manganese was 0.0384 mg/I with a range of 0.0249 to 0.0548 mg/I. CWI-DH-58 was perforated at eight different intervals with the second from the top perforation being the upper B -Seam. CWI-DH-58 was monitored from January, 1983 though October 11, 1990. The hole was reported as being dry during the period of record. The Applicant removed tubing from the well during August 2010 so it could confirm prior monitoring data. The Applicant confirmed CWI-DH-58 was dry to a level below the B -Seam. Beginning in 2011 the field technician has not been able to get monitoring equipment down to the water level. During August 2014 the Applicant was not successful in rehabilitating CWI-DH-58. Therefore, a replacement well CWI-DH-58A was drilled and completed in December 2014. For the period of record from October 2014 through October 2015 for CWI-DH-58A, the average field conductivity was 1,179 umhos/cm with a range of 1,050 to 1,270 umhos/cm, the average field ph was 8.8 with a range of 8.5 to 9.2, average total iron was 3.344 mg/I with a range of 0.573 to 9.270 mg/I and average total manganese was 0.2221 mg/I with a range of 0.0699 to 0.6240 mg/I. The Applicant installed two monitoring wells in 2011 to provide down gradient monitoring for the western mining district west of Terror Creek. One monitoring well (2010-1 B) is completed in the B -Seam with a screened interval of 1,190 to 1,220 feet. The second monitoring well (2010-1 SS) is completed in a sandstone water bearing zone located above the B -Seam with a screened interval of 1,120 to 1,140 feet. This sandstone water bearing zone above the B -Seam was identified at wells TC -03-02 and TC -03-03. Monitoring data for 2010-1 B and 2010-1 SS was reversed up through the end of 2013. The problem was discovered during the 2014 well rehabilitation project. The correct monitoring data was incorporated into the 2014 annual hydrology report. TR -99 2.04-35- 02/16