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Final Technical Report, 2014 Monitoring Well Rehabilitation Program Bowie Mine 24 <br />4.0 CONCLUSIONS AND RECOMMENDATIONS <br />Field work for the Bowie Monitoring Well Rehabilitation Program was initiated on July 22, 2014 <br />and concluded on September 20, 2014, spanning a total of 69 working days (including numerous <br />weather delays and a few mechanical interruptions). During the program, two deep monitoring <br />wells were successfully rehabilitated and one monitoring well was replaced. A well was <br />considered rehabilitated if the field water quality parameters of pH, conductivity, and <br />temperature of the well water were similar to groundwater quality values elsewhere in the mine <br />area. In spite of extensive efforts, it was not possible to rehabilitate three of the wells. <br />Well 2010 -1SS is 1,140 feet deep and is installed in the B- Sandstone above the Upper B -Seam. <br />Downhole video and tagline inspection indicated that casing and screens were intact. The well <br />was cleaned and developed using jetting and surge block techniques and water quality improved <br />from having a pH of greater than 12.0 s.u. to a pH of 9.75 s.0 during well development. The <br />electrical conductivity was 277 µmhos /cm and the temperature was 27° C. The post - <br />rehabilitation samples collected for laboratory analysis on October 16, 2014 had a field pH of <br />9.88 s.u. and lab pH of 9.74 s.u., the field and lab conductivity values were 378 and 336 <br />µmhos /cm, respectively, and the water temperature was 20.3 T. <br />Well CWI -DH -60 is 1,085 feet deep and is installed in the Upper B -Seam. Downhole video <br />indicated that the casing and screens are intact. The well was cleaned and developed using <br />jetting techniques and water quality was good with a pH 7.8, electrical conductivity of 930 <br />µmhos /cm, and temperature of 21' C. The post - rehabilitation samples collected for laboratory <br />analysis on October 20, 2014 had a field pH of 7.29 s.u. and lab pH of 7.45 s.u., the field and lab <br />conductivity values were 4,540 and 3,090 µmhos /cm, respectively, and the water temperature <br />was 16.0 °C. <br />Wells P- TC -03 -01 Upper and P- TC -03 -02 could not be rehabilitated for water quality data <br />collection, but they could still be used as piezometers for measuring groundwater level in the <br />Upper B -Seam and B Sandstone above the Upper B -Seam, respectively. Vandalism may be the <br />cause of the suspected t- post/object blockage in well P- TC -03 -01 Upper. <br />After a major effort of 24 working days, the 2 -inch well casing in well CWI -DH -58 came apart <br />below a depth of 1,580 feet, rendering the well completely inoperable. This well needs to be <br />abandoned in the future. Bowie plans to replace this well in the late fall 2014. <br />Well BRL- IP- 00 -67 -D -BLW was abandoned and successfully replaced with well BRL- IP- 14 -67- <br />D -BLW. On September 6, 2014, the static water level in the replacement well was 344.5 feet <br />btoc, the average pH was 7.93 s.u., average conductivity was 2,091 µmhos /cm, and the average <br />temperature was 20.9 °C. The samples collected for laboratory analysis on October 20, 2014 had <br />a field pH of 7.85 s.u. and a lab pH of 7.92 s.u., the field and lab conductivity values were 5,510 <br />and 3,930 mg/L, respectively, and the water temperature was 19.6 °C. <br />November 2014 HydroGeo, Inc. <br />