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Mr. Scott <br /> Response to Adequacy Review of a 112 Construction Materials Reclamation Permit Amendment <br /> Package, Derr Pit, Permit M2008-017 <br /> Page 2 <br /> 3. Need a sampling plan to establish baseline water chemistry and provide data to <br /> demonstrate compliance with GW standards. DRMS will determine if continued <br /> monitoring is required after reviewing baseline data. <br /> Response: <br /> Broken Arrow will obtain 2 samples each from monitoring wells MW-1 and MW-3, 30 days <br /> apart, and have the samples tested to establish the baseline water chemistry. These <br /> wells are on the downgradient side of the site. See the attached monitoring well map. <br /> Broken Arrow will provide the test results to the Division for review so that a baseline <br /> can be established. <br /> 4. Groundwater level triggers will need to be determined based on deviation from pre <br /> mining baseline average water level data, not on data from the previous year(s) that may <br /> lead to cumulative impacts prior to mitigation. Please revise. <br /> Response: <br /> The basis for groundwater baseline levels has been revised to be from groundwater <br /> measurements done prior to mining. See the attached updated Exhibit E narrative. <br /> 4a. Monthly water levels should be measured from here out to the hundredth of a foot below <br /> the survey reference elevation (industry standard). It would also appear that the well <br /> reference elevations were only surveyed to the nearest tenth of a foot? Resurvey will be <br /> required to the standard hundredth of a foot for this data going forward. Please confirm. <br /> Response: <br /> Future monthly water levels in the monitoring wells will be measured to hundredth of a <br /> foot accuracy. The top of monitoring well elevations were surveyed to the hundredth of a <br /> foot when they were installed. See the attached table in excerpt from Two Rivers Testing <br /> Subsurface Exploration Report. The top elevation of the wells will be resurveyed to the <br /> hundredth of a foot to verify their top elevations. <br /> 4b. DRMS will require standard monitoring well construction diagrams for all MW that were <br /> previously installed on site. (depth of well, screened interval, casing type, sand pack <br /> interval, seal type, etc...) <br /> Response: <br /> Details on the construction of the monitoring wells are not available at this time. We <br /> spoke with Jim Jehn of Jehn Water Consultants, and he confirmed that Jehn submitted <br /> the Notice of Intent to Construct Monitoring Holes (Division of Water Resources form <br /> GWS-51) for the 15 monitoring wells that were constructed. He said that Jehn was not <br /> present to document the construction of the wells when they were constructed. We also <br /> contacted Lane Christiansen, the drilling contractor, to inquire if they had records of the <br /> construction of the wells. They are looking back at their records to see if they have any <br /> information on the installation/construction of the monitor wells. At this time the only <br /> information we have is the depth of the monitoring wells as shown on the boring logs <br /> submitted to the Division in our Adequacy Review No.1 response. Broken Arrow will <br /> V 305 Denver Avenue-Suite D• Fort Lupton CO 80621 • Ph: 303-857-6222 • Fax: 303-857-6224 <br />