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Mr. Wayland <br />Page 2 <br />October 7, 2015 <br />not submit all of the information requested by the Division. As required by Rule 3.1.5(9), <br />please submit notice of backfill activity with the following information: <br />a. The approximate volume of inert material to be backfilled. <br />b. A signed affidavit certifying that the material is clean and inert. <br />c. The approximate dates the proposed activity will commence and end. <br />d. An explanation of how the backfilled site will result in a post -mining land <br />configuration that is compatible with the approved post -mining land use. <br />e. A general engineering plan stating how the material will be placed and stabilized in a <br />manner to avoid unacceptable settling and voids. <br />6.4.7 Exhibit G — Water Information <br />3. The Applicant has stated groundwater modeling studies conducted by Weiland Inc. for <br />similar operations in the Big Thompson River valley predict the cone of depression will <br />extend between 300-600 feet laterally from the BNER. The Applicant did not provide copies <br />of the referenced studies or any other data to substantiate these claims. The Division concurs <br />that a detailed groundwater model is not warranted for the dewatering and lining of the <br />BNER due to the shallow depth of the reservoir. However, the Applicant has acknowledged <br />the dewatering of the BNER will impact the local groundwater table. Therefore, the Operator <br />must commit to a mitigation plan in the event the dewatering and/or lining of the BNER <br />directly affects the ability of surrounding wells to pump a full supply of water in accordance <br />with their permitted uses. Mitigation measures should include the following: <br />a) Modify existing wells to operate under lower groundwater conditions. This would <br />include re -drilling existing wells to deeper depths or lowering the pumps. All work <br />would be done at the Operator's expense with the exception of replacing equipment <br />that was non-functional prior to mining. <br />b) If existing wells cannot be repaired, the Operator will drill a new well for the owner <br />to replace the damaged well. The new well will produce water of the same quantity <br />and quality to support the historic use. <br />c) Provide an alternate source of water to support the historic well water use during <br />mine dewatering. <br />d) If it is determined that lining of the BNER creates mounding or shadowing impacts to <br />surrounding structures or water resources, a subsurface drain will be installed to <br />transport water from mounding areas to shadowing areas. <br />4. The Applicant has requested the Division reconsider its request to implement a groundwater <br />monitoring program. A groundwater monitoring program can be beneficial to an Operator in <br />the event there is injury to a surrounding water right. Data collected through the groundwater <br />monitoring plan can serve to demonstrate that dewatering activities have not impacted nearby <br />wells or water rights. In the absence of groundwater monitoring data, which conclusively <br />demonstrates the dewatering operations have not impacted a water right, the Operator will be <br />