HYDRO30690 - Laserfiche WebLink

Home Browse Search

8 • Multiple Completion Monitoring Wells There are three multiple-completion monitoring wells (21-3, 21-4, and 29-4), that were installed in July 1999. These multiple-completion monitoring wells provide nested or co-located monitoring locations for the Uinta Formation, A-Groove, B- Groove, and Dissolution Surface. The multiple-completion monitoring wells were constructed in large-diameter boreholes to allow grout mixture to flow freely and fully seal the borehole between the completion zones. All well construction materials (sand, bentonite, and grout) were placed from the bottom of the borehole by the tremmie method. Each completion is constructed of 2-inch- diameter, PVC or fiberglass well casing and well screen. Well completion diagrams of each well are included in Section 2.0 along with the respective well history information and data summary tables. • Well 21-3 is located down-gradient of the first-phase mine panel and has four nested completion zones (Uinta, A Groove, B Groove, and Dissolution Surface). Well 29~ is located up-gradient of the first-phase mine panel and has three nested completions zones (Uinta, A Groove, and Dissolution Surface) and a co- located completion zone (B Groove) a few feet away on the same pad. The third multiple-completion monitoring well, designated as well 21-4, is located inside the northeast boundary of the 0-5 year mine panel. Monitoring well 21~t has three nested completion zones (A Groove, B Groove and Dissolution Surface), and an adjacent Uinta well completion (21-4U). In summary, the 25 well completions that constitute the baseline groundwater monitoring program at the Piceance Site include three Dissolution Surface completions (data for well 20-1 a fourth Dissolution Surface, Lower Aquifer well is included in this report although it is not part of the baseline monitoring . program), six B Groove completions, five A Groove completions, and one single