2000-04-11_PERMIT FILE - M2000002 ‎(3)‎

• Permit No: M2000002
• IBM Index Class Name: Permit File
• Doc Date: 4/11/2000
• Doc Name: PARTIAL REVIEW TANABE PIT 112 PERMIT APPLICATION M-2000-002
• From: DMG
• To: TOM SCHREINER
• Media Type: D
• Archive: No

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STATE OF COLORADO
DIVISION OF MINERALS AND GEOLOGY
Department of Natural Resources
1313 Sherman 51., Room 215
Denver, Colorado 80203
Phone [phone]
FA%:003) 832-8106
April 11, 2000
To: Tom Schreiner
Carl Mount
From: Harry Posey
Subject: Partial Review: Tanabe Pit 112 Permit Application; M-2000-002
This review is preliminary and subject to additional comments and refinement based on
information not received or perhaps not yet developed or available.
DIVISION OF
MINERALS
GEOLOGY
0.EC LAMATION
MINING•SAFETY
&II Owens
Governor
Greg E. Watcher
Enecutivc Director
Michael 8. Long
Division Di~edor
As indicated on various maps provided by the CDPHE and objectors, the proposed pit transects
an azea identified in 1994 as having elevated concentrations of diisopropylmethyl-phosphonate
(DIMP). The term "elevated concentrations," in this case, indicates concentrations in excess of 8
parts per billion - 8 ppb -which is the regulatory limit for drinking water.
[n addition, the maps indicate that the proposed gravel excavation will abut or will come within a
few hundred feet of the >8 ppb DIMP plume as identified in 1997.
Other contaminants from the Rocky Mountain Arsenal (RMA) are named as being present in the
area, but aze not located on the maps provided.
Based on the information from the 1994 and 1997 DIMP iso-concentration contour maps, it
appeazs possible that the proposed pit could intersect groundwater with elevated levels of DIMP,
and perhaps other contaminants. Moreover, it appears that groundwater pumping, which will be
necessary to effect dry mining, would lower water levels, locally, possibly drawing plume
contaminants into the pit or into the dewatering trenches. This observation is based on the
undocumented notion that the contaminant plumes from the RMA lie in the same shallow
alluvial aquifer that is proposed for mining, and on the further undocumented assumption that
current levels of contaminants are above drinking water standazds. If it is shown that the
contaminant plumes lie in aquifers deeper than the mining zone, then these concerns could be
moot.
I have contacted persons familiar with the current situation at the RMA and off site, and DMG
will meet with them for a briefing on local conditions as soon as possible. As the decision date
for this permit is fast approaching, and because the Division was apprised of the possible
groundwater contaminant conditions only recently, then owing to the Division's lack of