PERMFILE55140 - Laserfiche WebLink

Home Browse Search

~ Lott^~im l.:m'w~ llnir - Groun~hra: rr Tri!rniia! • at each site. Wells were set in nested contisurations with three wells to each drill site. At each site at least one well was installed in the coal (Primero or Ciruela), and one well each in the zone directly above the coal and below the coal in a zone [hat potentially is a water-bearing zone, typically sandstones. Each well was set into an individually drilled borehole. All wells were constructed of Schedule 40 PVC well casing and screen. All screens were 0.002 inch machine- slotted and equipped with 2'/•_ fog[ casing below the screens for capture of sediments. Screen intervals were eenerally five fee[ for the coals and ransed to ten feet for the sandstones. Silica sand (10/20 mesh) was installed for the length of [he screen and to two fee[ above the screen. Bentoni[e pellets were emplaced to 25 feet above the sand to form a seal, and the rest of the annular space filled to near surface with a bentonite slurry. Cement grout was added from ten feet to surface grade. Each well was fitted with an above-ground locking cover. All wells were installed in accordance with the guidelines of the State Engineers' Office. All boreholes drilled and abandoned were done so in accordance with Section 4.07. Copies of the construction diagrams and well logs for these wells are included in Appendix GW-1. All wells in the permit area are proposed for the life of the mine. Following the cessation of mining activities and the bond liability period, all wells will be abandoned in accordance with the standards in Rule 4.07. • Water Quality To determine the quality of the water within each formation samples were obtained from each well. Prior to sampling, each well was developed and field parameters obtained. Samples were then collected. The following methodology was utilized for water quality determination. Following the installation of the alluvial wells, each well was developed by repetitive surging of the water column within the well. This surging was accomplished utilizing a 3-inch Schedule 40 PVC bailer. Each well was surged until turbidity within the well effluent was substantially reduced. A minimum of three well volumes were removed or well production was performed until the well was dry. Followine this procedure, Held parameters were obtained and recorded. Subsequently, weds were sampled in accordance with 40CFR 136. Samples fr~~m each well were obtained via a PVC bailer. Each sample was collected according to the requirements of the parameters analyzed for Table G~V-3. Samples were preserved by cooling to 4'C and shipped for receipt by the laboratory prior within the required holding times. Each of these samples were analyzed for the constiruents found on Table GVV-4. Following the installation of the wells, sampling was performed to determine groundwater quality. Prior [o the initial sampling, each of the consolidated rock wells was firs[ developed by surging utilizing a 3-inch diameter 6 toot long Schedule 40 PVC bailer. The bailer was repeatedly surged back and forth in the well using an 8 horsepower wireline rig. Surging took place an initial fifty times in [he well bore, followed by bailing 10 to 15 gallons, and then repeating the procedure. A • minimum of three well volumes were removed in this manner, or the well bailed until turbidity cr„~~,~,,:~«ra-~ o,«~~~n~r~.:~,~„ 4 (revised 6/30/97)