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Allen Sorenson, Reclamation Specialist <br />Department of Natural Resources <br />Division of Minerals and Geology <br />1313 Sherman Street, Room 215 <br />Denver, Colorado 80203 <br />RE: File No. M77 -378, T -14 <br />Terry Tunnel Bulkhead wall irregularity <br />Dear Mr. Sorenson: <br />TABLE 1 <br />-r , <br />Si?NNYSIDE GOLD CORPORATION <br />AN ECHO DAY COMPANY <br />P.O. Box 177 . Silverton, CO 81433 <br />Phone (303) 387 -5533 .Telecopy (303) 387 -5310 <br />August 26, 1994 <br />The design assumption that enough perimeter area irregularity <br />exists at each of the bulkhead sites to prevent bulkhead failure by <br />thrust is to be confirmed prior to pouring of the bulkhead or a <br />design for shear pins is to be submitted to the Division if the <br />design assumption cannot be confirmed. Because of the relatively <br />small irregularity (0.15 ") and quantity (10% of the perimeter area) <br />of intact rock irregularities required, it would be very difficult <br />to verify if a bulkhead site was marginal in respect to these <br />design assumptions. The Terry Tunnel Bulkhead site is not <br />marginal. Attached are x- sections, long sections and plan sections <br />to provide documentation to demonstrate that the design assumptions <br />are valid. The following estimation of wall irregularity <br />percentage is similar to that provided for the F -L Brenneman <br />Secondary Bulkhead, F -L Brenneman Primary Bulkhead, B -L Brenneman <br />Secondary Bulkhead and B -L Brenneman Primary Bulkhead. <br />The x- sections show a tapering trend towards the back of the <br />bulkhead with local wide spots in the center of the bulkhead (see <br />Table 1). This trend can also be clearly seen by overlaying the x- <br />sections of the bulkhead ends (0 + 17.2 and 0 + 25.2). The <br />bulkhead will be adequately anchored against thrust movement. <br />SECTION X- Sectional Area (sq.ft.) Comment <br />0 + 17.2 97.72 Water -side <br />0 + 19.2 88.00 <br />0 + 22.2 95.30 <br />0 + 25.2 81.68 Air -side <br />III IIIIIIIIIIIIIIII <br />1994 <br />