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oii oiooiooiooooooio C~~~~ ~~wocc~o Q~® Q~§®~i~,v~~ November 30, 1993 y - ~ ~ 1645 Court Place DEC 03 1993 s°~~' Denver, Colorado 60202 Phone/FAX (3031629-9335 Wa 1 1 y Erickson Di:~l~ic~ c' :~..~ru..s a uec!ogy Colorado Division of Minerals and Geology 1313 Sherman Street 2nd Floor Denver, Colorado 80202 Re: Closure work at Trinidad Basin Mine Dear Wally: I delivered the mylar for the TBM site to your office while you were out yesterday. It should be helpful to you in the landowner notification of the final reclamation items. I have received the letter dated November 15, 1993 to Gary Hanisch from Dan Hernandez. I disagree with the need to conduct slope stability analyses on the impoundments leading to Pond 22-P4. The reasons for this belief are stated below: 1) The three impoundments are actually old sediment ponds 22-P5, 22-P6 and 22-P10. These ponds have approved P.E. designs in the permit located in the submittal of August 26, 1980 by Mineral resource and Engineering, Inc. The maps showing the approved designs are 8009-54, 8009-SS and 8009-S8. 2) These ponds have been in place since 1980 and have performed admirably with no maintenance whatsoever. 3) As a professional engineer involved with the site for many years, I can tell you that these embankments are free of cracking, bulging, seepage, slipping or any other signs of instability. I would be willing to sign documents as a P.E. that they are stable for permanent retention. The embankments themselves were actually the haul road for the trucks leaving the strip area. They were constructed with extremely heavy equipment and good compaction was achieved. 4) The landowner is likely to sign a waiver absolving anyone of future repercussions, should a problem with the ponds develop. This alone should warrant the slope stability analyses unnecessary. 5) There is no significant threat to life or property downstream if the ponds should fail. 6) 6Vhen all ponds on the west side of the property were designated to remain, no slope stability analyses were conducted. It is true that some steeper slopes exist on the outslopes of these embankments but they are no less stable. As stated above, these road embankments were built exceptionally well.