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w .~ Memo to GreQe Squire 2 April l2, 2000 approved, could not be altered without consent by the Division. The Operator would be required to advise the Division of [he schedule for construction of [he liner so that inspections could be scheduled at appropriate times during installation. The Operator would be further required to provide a construction report detailing the installation of the liner, describing any problems that occurred, and listing the results of testing that was conducted under the approved quality assurance/quality control plan. A certification would be required to accompany the construction report with a statement from the quality assurance engineer that the liner was constructed in accordance with the approved plans and specifications. With this level of regulatory control over the installation of the liner, the Division would gain a high degree of assurance that ground water will not leak into the pit at a rate in excess of criteria established by the State Engineer. With this level of assurance, the contingency bonding for repair or replacement of 20 percent of the total linear feet of liner would be acceptable. The application states that the property has been drilled. The logs from the drilling operation must be provided to facilitate the Division's review of the reclamation costs and mining setbacks. The drilling information should include a plan view illustrating [he locations of the borings, the logs of the subsurface features encountered in the holes, and the results of any geotechnical testing that was conducted. Information of the location, size, or nature of the gravel deposit may be submitted mazked "confidential" under Rule 1.3 if the Applicant so chooses. 4. The Applicant must provide a technical basis for the proposal to leave a 200-foot setback from the limit of mining to the South Platte River. Areas of the South Platte River within the Urban Drainage and Flood Control District, located just to the south of the proposed pit, are subject to 400 foot mining setbacks unless mitigative measures are employed. The Applicant's explanation of basis fora 200-foot setback should include a discussion of the depth and velocity of the 100-year flood through the mine reach and the potential for breaching of the river into the pits. 5. The application proposes mining within the river setback during the low flow season and brackets this season between October 1~' and May 1~' of each year. The Division will permit mining and backfilling within the setback during a single low flow season, but with the following conditions: • The low Flow season is defined as the period from October 1 s' to April 1 s` of each year. The potential for flooding in April is too significant to consider it a part of the low flow season. • The Applicant must specify a maximum encroachment area into the river setback that will occur in any given year, and the Division must hold sufficient bond to backfill the maximum specified encroachment area. • During each year that the reclamation permit for the Riverbend Pit is active, the Operator must provide to the Division of Minerals and Geology a signed affidavit stating that the required buffer zone is established between [he edge of the pit and the top of the river bank. The affidavit must be submitted by April 1s' of each year and must include a statement that the buffer zone will be maintained during the period from April 1s` through October 151.