HYDRO22568

• Permit No: M1977208
• IBM Index Class Name: Hydrology
• Doc Date: 11/7/2002
• Doc Name: Groundwater Monitoring for CKD
• From: DMG
• To: CEMEX Inc.
• Media Type: D
• Archive: No

STATE OF COLORADO
DIVISION OF MINERALS AND GEOLOGY
Department of Natural Resourtes
1313 Sherman S[., Room 215
Denver, Colorado 80203
Phone: [phone]
FAX: [phone]
November 6, 2002
To: Erica Crosby
From: Harry Posey Sv" -
Subject: CKD monitoring; Cemex, Lyo Quarry, M-1977-208, TR-01
Reviewing the file, it appears that DMG set out to establish baseline conditions
for CKD weathering at the captioned operation. The following sequence, from
1999 through 2001, synthesizes the monitoring plan and the results, and
proposes a set of numeric protection levels (NPL's).
DIVISION-OF
MINERALS
GEOLOGY
RECLAMATION
MINING•SA FETY
Bill Owens
Governor
Greg E. Walther
Executive Director
Ronald W. Cattany
Acting Division Director
Synopsis:
1. DMG required leach testing of CKD. Results indicated elevated selenium
(Se), thallium (Tl) ahd high pH. Conductivity, which is not regulated, was
selected as an indicator parameter.
2. DMG selected these parameters for monitoring plus conductivity as an
indicator for monitoring.
3. DMG also required that CKD be sprayed with water to promote crystallization.
4. The company was to submit 5 quarters of baseline analyses from A-Pit pond
for Se, TI, pH, and conductivity. This was accom lished__ _ --
e quarters of baseline monitoring and establish
NPL's. That proposal is forwarded in this memo.
6. Upon establishment of NPL's, the Company was approved to reduce
monitoring to twice yearly.
7. Based on monitoring results, Se and TI consistently reported below regulated
values. Data were good, detection levels were proper,
8. In aU cases, pH was within the allowable range for groundwater.
9. Conductivity was consistently high. Conductivity is not regulated.
Ordinarily, DMG requires 8 samples over the 5 quarters of baseline in order to
apply Dixon statistical methods to determine NPL's. Only 5 samples were
analyzed. However, as the metal values fell below the regulated values and as
pH was within the allowable range for groundwater uses, I would suggest that we
do not need 8 samples. Following are the results: