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s <br /> Mr. Edwin Olivares <br /> February 8,2018 <br /> Page 3 <br /> Given the close proximity to a borehole with significant water, it was decided to install a Fort Hays well in <br /> the dry borehole to monitor for any saturation that may develop or be detected over time. MW-6 was <br /> completed using a two-inch inside diameter Schedule 40 flush jointed,threaded PVC pipe and a screen slot <br /> size of 0.010 inches. Twenty-five feet of screen was placed,with the bottom of the screen was set at the base <br /> of the Fort Hays and the top at a depth of 30.9 feet. A sand filter pack(l 0/20 Colorado silica sand)was <br /> placed from the bottom of the well up to the top of the Fort Hays(28 feet BGS). A hydrated bentonite chip <br /> seal was placed from there up to a depth of 22.4 feet. A grout slurry(approximately 95%Portland cement <br /> and 5% bentonite gel)was then placed up to a depth of 2.8 feet. A steel surface protective tubing with <br /> lockable lid was then fitted and concreted into place. A four-foot by four-foot concrete pad was poured <br /> around the protective steel and 4-inch diameter steel concrete-filled pipe bollards were installed at each <br /> corner. All annular materials were placed as the drill string and then augers were pulled. Descriptions of <br /> shallow continuous core samples from the original borehole were used to supplement the descriptions for the <br /> MW-6 borehole log(Attachment A). <br /> Borehole Drilling and Well Construction:MW-7 <br /> Borehole drilling for drilling was MW-7 initiated approximately 18.5 feet NW of MW-6. The methods of <br /> drilling were the same as those at the MW-6 location. The original intention for MW-7 was completion in <br /> the Codell Sandstone. Lithology was essentially the same as that encountered in MW-6, until water was <br /> encountered in a fracture at approximately 47 feet BGS. The amount of water flow was significant and <br /> similar to that encountered in September in the initial borehole for MW-6. Given this finding, it was <br /> determined by CCG and GCC that it was more important to monitor this water source than to continue <br /> drilling into the Codell Sandstone. Therefore,a second Fort Hays well was installed as MW-7. <br /> MW-7 was completed essentially the same as MW-6,using a two-inch inside diameter Schedule 40 flush- <br /> jointed,threaded PVC pipe and a screen slot size of 0.010 inches. Twenty-five feet of screen was placed, <br /> with the bottom of the screen was set at the base of the Fort Hays and the top at a depth of 30.6 feet BGS. <br /> Sand pack(10/20 Colorado silica sand)was placed from the bottom of the well up to the top of the Fort Hays <br /> (27.5 feet BGS). A hydrated bentonite chip seal was placed from there up to a depth of 21.8 feet. A grout <br /> slung(approximately 95%Portland cement and 5%bentonite gel)was then placed up to ground surface and <br /> completed with a steel surface protective tubing with lockable lid. A four-foot by four-foot concrete pad was <br /> poured around the protective steel and 4-inch diameter steel concrete-filled pipe bollards were installed at <br /> each corner. All annular materials were placed as the drill string and then augers were pulled. <br /> Monitoring wells were constructed in accordance with applicable Colorado water well construction rules(2 <br /> CCR 402-2). Monitoring well locations are shown on Figure 1. Borehole Logs and Well Construction <br /> Forms are provided in Attachment A. For both wells,a Form No.GWS-31 (Well Construction and Yield <br /> Estimate Report)was filed with the Colorado Office of the State Engineer. <br /> Well development <br /> Each new well was developed to flush disturbed formation fines from the screened portion of the well and to <br /> help ensure representative flow from the entire screened interval of the well. Due to the very minimal <br /> amount of water in MW-6,the only development possible was to bail it dry several times. Development at <br /> MW-7 began with surging and agitating the water column with a decontaminated bailer to suspend fine <br /> particles of sediment so they could be removed by subsequent bailing. Surging was repeated throughout the <br /> development process to flush fine particles from the sand filter surrounding the well screen. <br /> Close Consulting Group LLC <br />