HYDRO24023

• Permit No: M1977208
• IBM Index Class Name: Hydrology
• Doc Date: 5/20/2004
• Doc Name: Monitoring Issues
• From: DMG Harry Posey
• To: DMG Erica Crosby
• Media Type: D
• Archive: No

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STATE OF COLORADO
DI`/ISION OF MINERALS AND GEOLOGY
Department of Natural Resources
1313 Sherman St., Room 215
Denver, Colorado 80203
Phone: [phone]
FA);: [phone]
Date: May 20, 2004
To: Erica Crosby
1=rom: Harry Posey~~~
13E: Monitoring issues~Cemex, Inc.; Lyons Mine; M-1977-208 '~
COLORADO
DIVISION OF
MIN SRALS
GEOLOGY
REC LAMRTION•M INING
SAFETT•SCIENCE
Bill Owens
Governor
Russell George
Executive Director
Ronald W. Cattany
Division Director
Natural Resource Trustee
"this memo addresses several features of groundwater monitoring and the recent report of a
possible excursion in selenium concentration at C-Pit.
Proposed revised groundwater monitoring parameters:
This memo presumes C-Pit is the upgradient groundwater monitoring point and A-Pit is the
downgradient compliance point, and that these are the only stations DMG has required for
groundwater monitoring.
The reason for monitoring groundwater at this site is that leach tests of cement kiln dust (CKD)
and leach tests of CKD plus tire derived fuel ash each reported concentrations of a few
regulated parameters in excess of drinking water or human health or agricultural standards.
l'he Lyons Mine permit requires twice-yearly monitoring of pH, conductivity, selenium, and
thallium, and reporting these with the annual report, except in the case of excursions outside
water quality standards. These are the parameters that exceeded standards in the leach tests
of CKD.
At issue is whether groundwater should be monitored also for parameters that exceeded
standards in leach tests of CKD plus tire derived fuel ash. For conservatism and completeness,
D believe they should. Therefore, based on evaluation of the SPLP results of CKD plus tire
derived fuel ash, which were reported to the Division on September 4, 2003, I would
recommend that the Division require that groundwater be monitored also for sulfate. Sulfate
was the only parameter that exceeded standards in the SPLP tests of CKD plus tire derived fuel
.ash.
Groundwater monitoring stations:
Several features are implicit to groundwater monitoring and should be put into practice at the
Lyons Mine if not already so.
1. Groundwater should be monitored downgradient of all contaminant sources.
2. Groundwater monitoring stations should include both monitoring (early warning)
points and compliance points. The number and placement of monitoring and
Office of Office of Colorado
Mined Land Reclamation Active and Inactive Mines Geological Survey