Laserfiche WebLink
W W RESOURCE <br /> `j HYDROGEOLOGIC <br /> e SERVICES <br /> planned monitoring well locations. The design for the six proposed monitoring wells is shown in Figure 2 <br /> and the design for the potential seventh monitoring well in Figure 3. <br /> BOREHOLE DRILLING & MONITORING WELL INSTALLATION - BEDROCK <br /> Bedrock well installation specification calls for: <br /> 1. Air rotary (with minimal potable water injection) drill 6-3/8-inch hole (bit size to 7-inch range <br /> okay) from surface through Fort Hayes limestone at the subject location. Hollow-stem auger <br /> drilling through the unconsolidated colluvium until bedrock refusal is acceptable to effectively set <br /> temporary casing through this interval provided that the auger inner diameter allows the bedrock <br /> borehole diameter to create a minimum 2-inch annulus between the borehole wall and the <br /> screen/casing per 2 CCR 402-2 State of Colorado Water Well Construction Rules, which for this <br /> project utilizing nominal 2-inch schedule 40 screen and casing is 6-3/8-inches. Air lift production <br /> test through blooey line to determine Fort Hayes flow rate via portable flume or bucket-and- <br /> stopwatch method. RHS will also collect standard field water quality parameters (temperature, <br /> pH, specific conductance)from the discharged water at this time.All drilling discharge water shall <br /> be discharged to the ground or a small infiltration pit as the site conditions warrant. For the three <br /> Fort Hayes monitoring wells, borehole drilling is now complete so move to step 3 below. <br /> 2. Air rotary (dry) advance 6-3/8-inch borehole from base of Fort Hayes limestone into Codell <br /> sandstone until either penetrating significant additional groundwater in the Codell or otherwise <br /> through the entire Codell sandstone member (expected thickness 6-25 feet). Air lift production <br /> test through blooey line to determine combined Fort Hayes and Codell flow rate via portable <br /> flume or bucket-and-stopwatch method. RHS will again collect standard field water quality <br /> parameters (temperature, pH, specific conductance)from the discharged water at this time. <br /> 3. Hang in tension from appropriate threaded installation plug or clamp 2-inch schedule 40 PVC <br /> environmental flush joint screen (0.020-inch factory-machined slot)from total depth to near top <br /> of either Fort Hayes or Codell, as appropriate for the location. Blank flush joint 2-inch schedule <br /> 40 PVC shall extend from the top of screen section to 2-1/2 feet above ground surface. Stainless <br /> steel bow spring environmental centralizers shall be placed at the bottom and top of each screen <br /> section and then every 20 feet to surface. All tubulars and centralizers shall arrive to site new, <br /> bagged and boxed. <br /> 4. Complete by 10-20 silica sand pack from total depth to 3 feet (typical) above the top of screen <br /> section via tremie pipe, with continuous depth tagging to the level specified by the RHS <br /> hydrogeologist. Bentonite seal shall be accomplished by pouring one 5-gallon pail of %-inch or <br /> 3/8-inch coated bentonite pellets via tremie pipe, hydrating with potable water as necessary if <br /> the hole is not holding water at this depth. The remaining annular seal up to ground surface shall <br /> GCC Rio GRANDE,INC.PUEBLO PLANT <br /> 2021 MONITORING WELL INSTALLATION PROGRAM WORK PLAN <br /> 6 <br />