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~~~ ~~~~~~~~~~~~~~~~ . Received MAR 2 9 ?001 D~'ision~n9o Field p . BALAZ ~ ASSOCIATES, INC. °fM~nerals~ao~y 1005 N. 12th St., #211 Grand Junction, CO 81501 Phone: (970) 263-9733 March 26 2001 RECE~VED ;' ~:-. ;, APR 0 2 2001 ~~I~L 1. r.; ~'~~ r~ ~ Mr. Steve Shuey ~~ ~ ~ ` Division of Minerals and Geology Division of Minerals and Geology ~J; C~ q~.,_ ~ Y 701 Camino del Rio, Room 125 `g,~ ~l. '/'7~'OZZ Durango, Colorado 81301 ~'~hr~~ Myj ''b Re: Conger Harvesting Area, Permit No. M-1998-022 RECE~~~~ ~ ~. ~ 4 Land Swap Technical Revision Application ~,~ Response to DMG Adequacy Review APR Q'2 2Q01 Dear Steve: Division of Minerals arty Geolotl~ Balaz & Associates, Inc., BAI, is submitting two (2) copies of this response to your Second Adequacy Review dated 02/26/2001 concerning the Land Swap Technical Revision application to the above referenced permit. This response includes: Item 1-Final slope cross section 0+50. The final slope shown on this plan is a transition zone from the 2:1 post mining slopes in the permit area and the steeper 1.7:1 natural slope to the east of the original staging area. These steeper, existing slopes appeaz to be stable as there is no physical evidence that the slope is moving. The potential impacts to the 12 inch DBH trees from mining and reclamation will be discussed in Item 4 below. 2. Item 2 - Highwall height in excess of 20 feet. Grand Junction Lincoln DeVore has reviewed the slope stability for cross section 3+00 which has a highwall height of 30 feet as measured from the crest. This bench was chosen as it has the greatest highwall height. This new analysis shows that the factor of safety for the I :1 highwall, 30 feet height ranges from 1.27 to 1.5 which indicates it is stable. The final reclaimed slopes have a factor of safety of 1.6. The factor of safety calculation varies depending on the method used. A copy of this new geotechnical analysis dated March ] 0, 2001 has been previously forwarded to your office. A second copy of this new geotechnical analysis is attached. No changes have been made to the either the mining plan or reclamation plan map for the following reasons: 1) a new geotechnical analysis has been completed showing that the slopes as designed are stable; and 2) a transition zone from the 2:1 post mining slope to the existing natural slope is needed to make the reclamation of the site visually pleasing without any abrupt slope changes. When the post mining slope grades into a steeper natural slope then _,