PERMFILE136535

• Permit No: M2001063
• IBM Index Class Name: Permit File
• Doc Date: 8/27/2001
• Doc Name: WATER QUALITY RESULTS UNIDENTIFIED PROJECT REDELOUD CREEK/HENSON CREEK MIDAS MINING CO M-2001-063
• From: DMG
• To: BOB OSWALD
• Media Type: D
• Archive: No

STATE OF COLOlZ~DO
DIVISION OF MINERALS AND GEOLOGY
Department of Natural Resour ces
1313 Sherman $[., Room 215
Denver, Colorado 80203 DIVISION O F
Phone: [phone] MINERAL S
FAX: [phone] &
GEOLOGY
R E C L A M A T I O N
August 27, 2001 MINING•sAFETY
To: Bob Oswald Bill Owens
~ /
~ Governor
From: p
/
Harry Posey
/T/C/~V Greg E. Watcher
Executive Director
Sub'ect:
J Water uali results, Unidentified Pro ect, Redcloud Creek/I-Ienson Creek, Midas Michael a. Long
q 4' J Division Director
Mining Company, M-2001-063
The subject documents were sent to me for comment. Following are a few pertinent observations.
1. Based on conversation with you, [he data apparently were collected from the following points:
Sample Name Description
Portal Portal discharge prior to entering sediments upstream from
Redcloud Creek
Above Portal Redcloud Creek, upstream from portal discharge.
Henson A Henson Creek, above Redcloud Creek
Henson B Henson Creek, below Redcloud Creek
2. Samples were collected July 6, 2000. Flow at that time would be near the its lowest of summer
discharge, would not likely contain spring snowmel[, and would no[ represent "critical low flow"
(winter). I[ is feasible that winter metal concentrations would be lower than [hose measured in July.
3. All samples have slightly alkaline pH.
4. All hardness values are low. Thus, low metals concentrations should be evaluated closely.
5. A few AI, Mn and Zn values in dle Portal and Redcloud Creek samples approach or exceed water
quality limits for an aquatic life class L fishery. Having detailed, high quality information on record
prior to mucking with the portal discharge or [he site would be useful.
6. Not knowing the composition of sediment ponds outside the portal, it is not possible to gauge then
effects on water quality, but it is feasible that the sediments provide contaminants [o the portal
discharge water. There is limited suggestion that water quality below [he portal discharge to Redcloud
Creek is degaded relative to Redcloud creek above the portal, but more sampling would be needed to
affum this suggestion. It would be advisable to determine this prior to the proposed mining.
7. No organic parameters appeazed in any analysis.
8. All of [he analyses appear to have been analyzed a[ appropriately low detection levels.
9. The lower pH, higher Zn and higher Nitrate values of the portal, relative to all other analyses, suggests
[hat acid drainage may be forming in [he adi[ drainage, and that underground sources of nitrate,
possibly from prior blasting, are active. Sampling during winter and spring snowmel[ is recommended
for [he portal discharge, preferentially below the sediment pond, to more clearly evaluate the AMD
potential.
Overall, there is limited evidence from these data the the portal discharge taps at least a slight source of
acidic drainage and an[hropogenic sources of nitrogen. If [ha[ is the case, poorer water quality could be
expected from the portal during spring snowmelt. Also, [he effects of water rock interaction from the
sediment pond is not evident in the data but cannot be dismissed. Sampling below the sediment ponds,
either in the discharge itself or in Redcloud Creek below [he site, is recommended.
- ~., d-