2009-10-28_REVISION - C1982056 ‎(3)‎

• Permit No: C1982056
• IBM Index Class Name: Revision
• Doc Date: 10/28/2009
• Doc Name: Email Correspondence Between Jerry Nettleton & Tom Kaldenbach ‎(Various Dates)‎
• From: Jerry Nettleton
• To: DRMS
• Type & Sequence: PR8
• Email Name: TAK
• Media Type: D
• Archive: No

Regards,
Jerry
From: Thompson, Keith [mailto:[e-mail]]
Sent: Thursday, October 29, 2009 1:18 PM
To: Nettleton, Jerry
Subject: RE: PR09-08 Technical Adequacy Response III
Yes, the K for the Twentymile Sandstone should be 1.4x10'2. 1 had used the value for the Trout Creek Sandstone for the
calculations. The correction substantially shortens the time frame for the spread of drawdown outward from the mine
area. A revised copy of the text is attached. I still believe the simulated conditions are highly unlikely to occur, for two
main reasons: 1) the propagation of subsidence fractures through the overburden is so unlikely beyond a couple hundred
feet above the mine, and 2) even if subsidence fractures did propagate all the way up through 670 feet of overburden
(which includes 590 feet of marine shale), the chance of the fractures in the marine shale staying open long enough to
allow the Twentymile Sandstone to drain into the mine is extremely small.
Please call or email me with any other questions or concerns. Thanks.
Best regards,
Keith
Keith Thompson, P.G. I Sr. Project Manager
Direct: 970.304.01401 Cell: 307.259.7824 1 Fax : [phone]
Tetra Tech I Complex World, Clear SolutionsT"
1949 26th Ave Ct I Greeley, CO 80634 1 www.tetratech.com
3801 Automation Way I Fort Collins, CO 80525 1 www.tetratech.com
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From: Nettleton, Jerry [mailto:][e-mail]]
Sent: Thursday, October 29, 2009 12:57 PM
To: Thompson, Keith
Subject: FW: PR09-08 Technical Adequacy Response III
From: Kaldenbach, Tom [mailto:[e-mail]]
Sent: Thursday, October 29, 2009 12:56 PM
To: Nettleton, Jerry
Subject: RE: PR09-08 Technical Adequacy Response III
Jerry,
Only one comment: Should the Twentymile Sandstone hydraulic conductivity from page 64 of Robson and Stewart be
1.4 X10-2, rather than 5.1 X 1-3? Please revise the analysis , if necessary to reflect the correct value.
Tom
From: Nettleton, Jerry [mailto:][e-mail]]
Sent: Thursday, October 29, 2009 10:23 AM