2010-03-04_REVISION - C1996083 - Laserfiche WebLink

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INTEROFFICE MEMORANDUM Date: 04 March 2010 To: Joseph J. Dudash, Lead Specialist From: Marcia L Talvitie, P.E. Subject: Bowie No. 2 Mine - Permit No. C-1991-083 TR-65 - Amend B-Seam Mine Plan and Add Geotech Hole Geotechnical Adequacy I have reviewed BRL's response to the adequacy issues listed in my preliminary review letter to you dated the 8th of January. The original TR-65 application included a March 2004 study prepared by Maleki Technologies, Inc. ("MTI 2004") entitled "Overburden Stability Evaluation at Terror Creek Crossing". The adequacy response package included an updated report from Maleki, bearing the same title, dated January 2010 ("MTI 2010"). My comments updating each of my original adequacy items are presented in bold type below. Items have been numbered to match the system used in your Preliminary Adequacy Review letter. MTI 2004 Section 2.0 - Data Collection Program 14. Three geotechnical holes were drilled, and are illustrated on Figure 1. The locations of these three holes with respect to one another differ from what is shown on Map 09. Please verify that locations shown on Map 09 for geotechnical holes TC-03-01, TC-03-02 and TC-03-03 are accurate, and revise if necessary. Locations shown on Map 09 were correct; MTI 2010 Figure la was revised accordingly. Item resolved; no additional response is required. 15. Page 6 of MTI 2004 states that holes TC-03-02 and TC-03-03 "were drilled directly above the projected location of the mains." TDR cables were cemented in all three holes (see Page 8), providing a means of "identifying the location of bed separation and shearing along the entire overburden." With the new proposed location of the West Mains, the TDR cables installed previously would not seem to be able to provide BRL with the same level of information. However, revised pages 2.05-120 and -125 describe and list four subsidence monuments proposed