1994-04-21_REVISION - M1977378 - Laserfiche WebLink

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1111111111111111111 999 St?31 NYSIDE GOLD COSIPOAATI&N AN ECHO 8"COMPANY P.O. Box 177 .Silverton, CO 81433 Phone (303) 387-5533 .Telecopy (303) 387-5310 April 18 , 1994 Allen Sorenson, Reclamation Specialist D partment of Natural Resources ivision of Minerals and Geology 1313 Sherman Street, Room, 215 Denver , Colorado 80203 RE: File No. M77-34, TR-14 B-L Brenneman Secondary Bulkhead wall irregularity Dear Mr . Sorenson : The design assumption that enough perimeter area irregularity exists at each of the bulkhead sites to prevent bulkhead failure by thrust is to be confirmed prior to pouring of the bulkhead or a design for shear pins is to be submitted to the Division if the design assumption cannot be confirmed. Because of the relatively small irregularity (0. 15" ) and quantity (100 of the perimeter area) of intact rock irregularities required, it would be very difficult to verify if a bulkhead site was marginal in respect to these design assumptions. The B-L Brenneman Secondary Bulkhead site is not marginal . Attached are x-sections, long sections and plan sections to provide documentation to demonstrate that the design assumptions are valid . The following estimation of wall irregularity percentage is similar to that provided for the F-L Brenneman Secondary Bulkhead and F-L Brenneman Primary Bulkhead . The x-sections show varying x-sectional area (see Table 1) with the largest section being towards the center of the bulkhead. This area is larger because it is towards the end of a round and was selected as the site for the air-side bulkhead because it provides a natural local low to further wedge the bulkhead against thrust . The section following the bulkhead (when overlain) shows additional taper beyond the bulkhead. The bulkhead will be adequately anchored against thrust movement. TABLE 1 SECTION X-Sectional Area (sq. ft . ) Comment 0 + 10. 55 78 . 41 Water-side 0 + 11. 55 79. 52 0 + 12. 55 79. 88 0 + 13. 55 73 . 40 Air-side