2009-05-14_REVISION - C1980007 - Laserfiche WebLink

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Dan Daniell. Hernandez Daniel I. Hernandez Senior Environmental Protection Specialist Colorado Division of Reclamation, Mining and Safety 1313 Sherman St, Room 215 Denver, CO 80203 New Phone Number: 303-866-3567 ext 8126 Fax: 303-832-8106 Website: www.minina.state.co.us From: Welt, Kathy [mailto:KWelt@archcoal.com] Sent: Wednesday, May 13, 2009 4:05 PM To: Hernandez, Daniel; Kaldenbach, Tom Cc: Berry, David; Nolte, Doug; Sweetwood, Ryan; Nyikos, Chris Subject: RE: MR 354 - Geotech Boreholes Dan, I've discussed your e-mail below with MCC's and our consulting engineers and provide the following responses to your comments. I believe that your two primary concerns are in regard to light-use road designs and drilling into the abandoned Oliver Mine workings. In regard to drilling into the Oliver Mine workings, it was decided that the best geotechnical data would be obtained by drilling near, but not into the abandoned Oliver Mine workings. It is data from the strata that was mined and above the mine (not the void or caved rubble) that will provide the best information to assist in the interpretation for the stability analysis. The attached project description has been revised to reflect this change. In regard to access to these borehole sites, I've understood you to say that the CMLRB regulations do not allow for any access construction for any period of time or level of use (such as a one time use, temporary access to a soil boring site), and must be designed per the road rules at 4.03. As such, MCC has added language to our permit text (see the page attached) to state that such temporary access may occur per Rule 4.03.3 utilizing field design methods - i.e. not pre-engineered with detailed road designs inserted into our permit for our permanent facility and operations, rather an access that is field fit (i.e. field designed) and constructed by an earthwork contractor experienced in the construction of light-use roads in our locale (i.e. one that knows the soils and terrain and how to build the roads to minimize erosion and sedimentation) for the one-time use and then removed and reclaimed as soon as the sampling is completed. It should be noted that the 1,330 feet of new access construction is considered the worst case scenario. The use of existing roads and trails, even where MCC has depicted new access, will be maximized and with the only deviations occurring where the new construction would result in a better light use road field design (i.e. one that would minimize disturbance and associated erosion and sedimentation.) The existing roads and trails that are planned to be utilized will not be upgraded for other uses. They will merely be cleared of rock debris and vegetative overgrowth to allow for the borehole and sampling equipment to enter the sampling site. It should also be noted that the entire area of the proposed sampling will ultimately be obliterated by the future proposed coal refuse pile. I've also understood you to say that the six minor revision applications that were approved by the CDRMS for MCC's prior soil and geotechnical investigations, including access to those sites, were inappropriate. Having been involved with most of those revision applications and knowing that the applications that were prepared and approved after I'd left MCC were done by very competent persons (at both MCC and the Division), I disagree that any "creep" away from acceptable