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Memo to Russ Means 7 November 14, 2007
<br />Bulkhead Cost Estimate File No. M-2007-044
<br />commingling of aquifers of varying water quality must be prevented. This is why the contingency of a
<br />second and overlying decline bulkhead is necessary. This is also the reason for requiring ground water
<br />monitoring down gradient of the decline bulkheads (see DRMS memo: Allen Sorenson to Russ Means, 11-
<br />6-07). Moreover, the Applicant must recognize that if the bulkheads are shown to be ineffective in
<br />minimizing adverse impact to the hydrologic balance, the DRMS may require the resumption of mine
<br />pumping and water treatment unless and until alternative water management plans are approved. In the
<br />unlikely event that perpetual water treatment is necessary, the DRMS will require that the reclamation
<br />permit be amended to incorporate the water treatment facilities into the post mining land use, and bond
<br />release maybe delayed or not allowed. Regardless of the DRMS bonding status, the Colorado Water
<br />Quality Control Division will regulate ongoing operation of the facilities. It should be noted that if DRMS
<br />thought that the need for perpetual water treatment was a likely eventuality, we would recommend that the
<br />Mined Land Reclamation Board deny this permit application.
<br />References
<br />American Concrete Institute, 1977, "Building Code Requirements for Reinforced Concrete (ACI 318-77)."
<br />American Concrete Institute, 1989, "Building Code Requirements for Reinforced Concrete (ACI 318-89)."
<br />Bredehoeft, J.D., Wolff, R.G., Keys, W.S., and Shuter, E., 1976, "Hydraulic Fracturing to Determine the
<br />Regional In Situ Stress Field, Piceance Basin, Colorado," Geological Society of America
<br />Bulletin Volume 87, Pages 250-258.
<br />Caterpillar, Incorporated, 1993, Caterpillar Performance Handbook, Edition 24, Page 24-4.
<br />Einarson, D.S., and Abel Jr., J.F., 1990, "Tunnel Bulkheads for Acid Mine Drainage," in Proceedings
<br />International Symposium on Unique Underground Structures. Vol. 2, Pages 71-1 to 71-20,
<br />Denver, Colorado, U.S.A.
<br />Garrett, W.S., and Campbell Pitt, L.T., 1961, Design and Construction of Underground Bulkheads and
<br />Water Barriers", Seventh Commonwealth Mining and Metallurgy Congress, Volume 3, Pages 1283
<br />to 1301.
<br />Wang, C-K, and Salmon, C.G., Reinforced Concrete Design, 4th Edition, Harper and Row, Publ., Inc.
<br />enclosure(s)
<br />cc: David Bird, DRMS (via email, w/enclosures)
<br />Kate Pickford, DRMS (via email, w/enclosures)
<br />Berhan Keffelew, DRMS (via email, w/enclosures)
<br />Carl Mount, DRMS (via email, w/enclosures)
<br />c:~acs files\My Documents 4-19-09 thru\whirlwind mine bulkhead cos[ esfimate.doc
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