PERMFILE61041

• Permit No: M2006018
• IBM Index Class Name: PERMIT FILE
• Doc Date: 5/19/2006
• Doc Name: Adequacy Response
• From: Gustavson Associates
• To: DMG
• Media Type: D
• Archive: No

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GLISTAVSON ASSOCIATES
GEOLOGISTS ENGINEERS APPRAISERS
May 19, 2006
Mr. Tom Schreiner
Environmental Protection Specialist
Department of Natural Resources
Division of Minerals and Geology
1313 Sherman Street, Room 215
Denver, Colorado 80203
Re: North Bank Pit -Regular 112 Permit Application
Response DMG to Adequacy Letter dated May 1, 2006
Dear Tom:
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Lafarge has crafted the following response to your list of questions in your letter dated May 1,
2006 and entitled "Adequacy Review Comments -North bank Pit Regular 112 Application".
We have answered the questions in the same order as you poised them. Our responses are as
follows:
6.4.2 EXHIBIT B -Index Map
Lafarge would be pleased to provide the DMG with as recent aerial photograph of the site, which
documents the conditions as they currently exist. We have included 2 copies of EXHIBIT C
Sheet 1 with the photos.
6.4.4 EXHIBIT D -Mining Plan
2. Period of time: Dewatering typically occurs in advance of and during active mining of an
area. Since Lafarge uses a "portable crushing type of operation", that is completes campaigning
crushing and stockpiling the dewatering is not constant, but intermittent. Based on experience at
Mamm Creek, dewatering typically occurs for all of part of 12 months per year. The rest of the
time the pit is allowed to contain water.
Maximum de-watering rate: Once again, based on Mamm Creek experience, Lafarge
expects the maximum rate to be 750 gpm and the normal sustaining rate to be 250 gpm.
5757 Central Avenue ~ Phone [phone]
Boulder, Colorado 80301 GUSTAVSON ASSOCIATES Fax: [phone]