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Memo to Erica Crosbv 3 Julv 8, 2002 The foregoing diagram illustrates that establishment of the enforceable setback from the structure to be protected to the toe of the pit slope, rather than establishing the setback distance from the crest of the slope, provides the pit Operator with the flexibility to mine the working face at any angle, and will limit the potential for the Operator to be found non-compliant with a permit condition. In the example illustrated, from a structural protection standpoint, a setback of 40 feet from the Fulton Ditch to the crest of a 1.SH:1 V working slope is equivalent to a setback of 95 feet from a near vertical conventional gravel pit mining slope is equivalent to a setback of 107.5 feet from the toe of the slope in a 45 foot deep pit regardless of working face slope angle. The diagram further illustrates that it is logical to establish the enforceable setbacks from the location of the stmcture to be protected rather than from an easement line. This is because the relationship of the easement line to the actual location of the structure can fluctuate over a wide range. In the example illustrated, the west edge of the Fulton Ditch is only 15 feet from the easement line. In this case, the requirement fora 40 foot setback from the edge of the ditch supersedes the requirement to setback 10 feet from the easement line, as will be case any time the edge of the ditch is 30 feet or closer to the easement line. To summazize, DMG will accept the Applicant's proposed setbacks with the strict condition that the working pit slope not exceed 1.SH:1 V and the condition that a minimum setback of 40 feet be maintained from the crest of the 1.SH:1 V pit slope to the edge of the ditch. The DMG suggests that the Applicant consider a permit commitment to maintain a setback measured from the toe of the pit slope rather than from the crest of the pit slope in order to facilitate compliance with the mined land reclamation permit. Item No. 2 -Reclamation Bonding for Clay Liner Installation The Applicant is requesting consideration under the 20 percent bonding option described in [he DMG publication "Guide to Specification Preparation for Slurry Walls and Clay Liners as a Component of a Colorado Mined Land Reclamation Permit," September 2000 (DMG Guide). On page 14 of the DMG Guide it is stated that: The basis of any bonding scheme is predicated on the basis for all reclamation bonding; that at any point in the life of the operation of a pit, the state must hold sufficient bond to implement the approved reclamation plan and establish the approved beneficial post mining land use. The approved beneficial post mining land use for [he 124`h Estates Pit is Developed Water Resources in the form of a sealed, clay lined reservoir. At this time, the basic steps required to install the liner and achieve the approved ]and use consist of: • Complete the excavation of the pit to clay stone bedrock and prepare the keyway and side slopes to receive the clay liner fill. • Strip and moisture condition clay stone to be used as liner fill; place and compact the liner fill on the prepared side slopes. • Install the required wedge of liner cover fill.