Laserfiche WebLink
October 26, 2004 <br />Mr. Allen C. Sorenson Y <br />Reclamation Specialist <br />Division of Minerals and Geology <br />1313 Sherman Street, Room 215 <br />Denver, CO 80203 <br />RECi~IVEp~ <br />OCT 2 g 2004 <br />Division ~f Minerals and Cealogy <br /> <br />AGGREGATE <br />INDUSTRIES <br />Re: Permit No. M-1999-021 -Stegner Farms -Technical Revision TR-004 <br />Response to Adequacy of Technical Revision Request <br />Dear Allen: <br />This letter is provided in response to adequacy items to be addressed as contained in your letter <br />dated August 31, 2004. Each item is listed in italics as presented in your letter, followed by our <br />response. <br />1. Please provide specifications for the pipes to be used to construct the perimeter drain <br />and the design basis for the type ofpipe selected. <br />Eight-inch perforated pipe will be used throughout the gl•oundwater interception areas <br />along the north and west boundaries, transitioning to an 8-inch solid pipe. The solid pipe <br />will be transitioned to a 6-inch perforated pipe in the dovvngradient re-charge area. <br />Please refer to the enclosed pipe descriptions as provided by Hughes Supply Inc. to <br />Aggregate Industries contractor Dirt Doctors. Six-inch pipe was originally proposed <br />throughout the perimeter drain system based upon a design analysis prepared by <br />professional engineer Stan Peters of Castle Rock Consulting. A summary of his design <br />basis is enclosed herewith by letter dated October 7, 2004 addressed to my attention. The <br />upgradient perforated pipe and the solid pipe sections wc;re up-sized to assure adequate <br />carriage during significant stone events <br />2. Provide a design and specification for the pipe bedding to be installed and either provide <br />a demonstration that the bedding will have filter compatibility with the surrounding soil <br />or commit to wrapping the perforated sections ofpipe with a geotextile filter fabric sock. <br />All pipe sections will be placed in a minimum 2-foot wide trench with a 6-inch depth of <br />1/8-inch x 1/4-inch squeegee pipe bedding. Perforated pipe sections of the perimeter <br />drain will then be covered to a depth of 1-foot with 1-1/:>" gravel wrapped in geotextile <br />filter fabric. Trench spoils will be used to backfill over t:he pipe bedding to original <br />grade. <br />3. The DMG will require a demonstration that the perimeter drain, once completed, is <br />functioning to adequately stabilize ground water levels outside the slurry wall. Please <br />Aggregate Industries <br />West Central Regton, Inc. <br />1707 Cole Blvd., Suite 100 <br />Golden, CO 80401 <br />Telephone:303-985-1070 An Equal Opportunity Employer <br />