Laserfiche WebLink
3.3 CM93 -3 <br />Observation well CM -3 was drilled to provide a means of sampling the <br />ground water in the first aquifer at a distance from, and downgradient of the <br />Burbank Repository (Figure 1). CM93 -3 was spudded on 4/8/93 and surface <br />casing set 4/13/93. The cement plug below the surface casing was drilled out on <br />4/22/93 and drilling of the borehole was completed on 4/26/93. The well was <br />logged on 4/27/93 prior to construction (Figure 4). This well was completed on <br />5/20/93 and a dedicated pump installed. <br />3.3.1 Well Construction <br />An eight inch steel surface casing was set from surface to a depth of 350 <br />feet with 18 inches above ground level. The steel casing was cemented in place <br />with a cement grout containing 5% bentonite. This casing was set to the <br />Summerville in order to protect the underlying aquifer from ground water in the <br />Salt Wash member of the Morrison formation. <br />A 7 7/8 inch hole was then drilled, with air, to a depth of 690 feet (Figure <br />4). The well was the developed by air jetting and evacuating the water from the <br />well until all cuttings were removed from the well and the water entering from <br />the formation was clean. This was accomplished prior to constructing the well. <br />The well was then constructed (Figure 4) using 120 feet of slotted (0.02), 4 <br />inch, flush joint, schedule 40, PVC pipe from 680 feet to 560 feet. An unslotted <br />section of pipe with a with a PVC cap on the bottom was placed from 690 to 680 <br />feet. Unslotted, 4 inch, flush joint, schedule 40, PVC pipe was placed from a depth <br />of 560 feet to 18 inches above the surface level. Gravel pack ( #10-20 Colorado <br />Silica Sand) was placed from the bottom of the well to a depth of 535 feet. A 20- <br />foot bentonite seal was then set from a depth of 515 feet to 535 feet using <br />12 <br />