2005-01-11_REVISION - M1999120 (3)

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L.G. EVERIST, INC. Rock Solid Since 1876 ~/ dba Andesite Rock Company January 7, 2005 Ms. Kate Pickford Environmental Protection Specialist Division of Minerals and Geology 1313 Sherman St., Room 215 Denver, Colorado 80203 Via Mail and Facsimile (303-832-8106) RE: L. G. Everist, Inc., Fort Lupton Sand and Gravel Mine, DMG #M-1999-120; Second Adequacy Response Letter Dear Ms. Pickford: ~ J~~ ~ 't 255 'p~uision et is=~,etals ~ feota8'I Thank you for reviewing our Adequacy Response, dated January 3, 2005, so quickly. This second Adequacy Response Letter is to address the two questions which you had from reviewing our initial adequacy response. We hope this clears up all issues for approval by our current recommendation date of January 10, 2005, rather than having to ask for an extension. One question was about the slurry wall construction, and whether or not the mix of topsoil, overburden, and fines from the sedimentation ponds, should be tested now to make sure that the plasticity index (PI} was adequate for slurry wall construction. The answer is "Yes." All material used to construct the slurry wall will be tested to insure that it meets the approved design criteria. The required slurry wall construction design, including materials testing will be done prior to disturbance of each phase and will be submitted as part of a Technical Revision, along with a 100 percent bond for the construction of the slurry wall. In March of 2004, during preparation of the permit application, we asked Allen Sorenson of the Division if we could bond in phases, and he agreed that we could bond for each slurry wall in sequence. He recommended that the designs, specifications, and quality assurance plan be submitted to DMG with the amendment or as a technical revision prior to initiating construction of the slurry wall. In Exhibit L in the application, we state that we will bond each phase prior to disturbance, via Technical Revisions that address the type of liner to be used (slurry wall or clay liner). Further, in our first adequacy response, we refined our reclamation plan by committing that we will seal each mining phase with a slurry wall, no clay liners. When we submit our Technical Revision for the bonding of the first mining phase of the amendment area, we intend to bond for 100 percent of the installation or replacement cost of the slurry wall, unless the construction design is approved by the Division of Minerals and Geology (DMG) fora 20 percent bond. The Division of Minerals and Geology's "Guide to Specification Preparation for Slurry Walls and Clay Liners as a Component of a Colorado Mined Land Reclamation Permit, September 2000," states that if an applicant chooses the 100 percent bond option, the applicant does not have to submit a slurry wall construction design. Also, we committed in the application materials (Exhibit D, Mining Plan), that we will be constructing the slurry wall to the Office of State Engineer's specifications, by following the "State Engineer Guidelines for Lining Criteria for Gravel Pits, August 1999." rr ~f - ~ MOUNTAIN DIVISION OFFICE 7321 E. 88TH AVENUE • SUITE 200 HENDERSON, COLORADO 80640 303-287-9606 FAX 303-289-1348 CORPORATE OFFICE 300 S. PHILLIPS AVE. • SUITE 200 P.O. BOX 5829 SIOUX FALLS, SD 57117-5829 PHONE 605-334-5000 FAX 605-334-3656 ~~~'(t~a~~ LM/FL-DMGAtleq uacyResp2-010705.doc