HYDRO26346

• Permit No: M1980244
• IBM Index Class Name: Hydrology
• Doc Date: 3/7/1997
• Doc Name: CRESSON PROJECT SAMPLING LETTER
• From: DMG
• To: BRUCE HUMPHRIES
• Media Type: D
• Archive: No

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STATE OF COLORADO
DIVISION OF MINERALS AND GEOLOGY
Depanmenl of Natural Resources
171 J Shcrman St., Room 215
Denver, Colorado 80203
Phone: [phone]-]567
FAX: [phone]
DATE: March 7, 1997
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TO: Bruce Humphries
Berhan Keffele~~~,,,
FROM: Harry Posey /~ ~YO;~ l
RE: Cresson Project Sampling Letter
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DEPARTMENT OI
NATURAI
RESOURCE:
Roy Romer
Governor
lames S. Lochhead
E><ecolive Direcror
Michael B. Long
Division Director
This is the rough draft of a proposed letter to CC&V about
unresolved issues of acid rock drainage. The concerns about acid
rock drainage potential were detailed in my pre-hearing statement
for the CDPHE/CC&V hearing. However, the issue of what type of
sampling should be conducted, if any, still lingers.
There are four issues:
a. Leach Tests indicate that ARD will develop in a
significant amount of rock. However, the company has
concluded that such potential does not exist.
b. The permit directs the operator to handle the waste rock
selectively on the basis of sulfur content. Material with
>0.8$ S and <0.8~ S are to be stored in separate areas.
However, even though this is a permit condition, there is
nothing inherently protective about these sulfide values that
indicates the ore can be selectively stored without other
protective measures to prevent weathering. Also, the S values
have never been adequately tied to dissolved metal content, so
even if the selective handling were protective for acid
production, we cannot say it is protective for metals.
c. The leco furnace analyses for sulfur indicate where the
rock came from in the Cresson pit, but it does not verify
where the waste rock was placed.
d. The Division contends, based on the operator's leach
tests, that the waste rock must be protected from weathering.
However, such a protection plan has not been submitted by the
Operator, and so is not part of the EPP, and has not been
bonded.
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