2001-01-25_REVISION - M1977208

• Permit No: M1977208
• IBM Index Class Name: Revision
• Doc Date: 1/25/2001
• Doc Name: REVIEW A PIT MONITORING RESULTS SOUTHDOWN LYONS QUARRY M-77-208
• From: DMG
• To: CARL MOUNT
• Type & Sequence: TR1
• Media Type: D
• Archive: No

~II II~~I~~III~~I ~I~
999
STATE OF COLORADO
DIVISION OF MINERALS AND GEOLOGY
Department of Natural Resources
1313 Sherman SL, Room 215
Denver, Colorado 80203
Phone: [phone]
FA\:[phone]
January 25, 2001
To: Carl Mount
From: Harry Posey
Subject: Review: A-Pit Monitoring results, Southdown Lyons Quarry, M-77-208
DIVISION OF
MINERALS
GEOLOGY
RECLAMATION
MINING•SAFETY
Bill Owens
Governrrr
Creg E. lvalcher
Eaecubve Director
Michael B. Lon{t
Divieon Dimcbr
Second and third quarter analytical results for the A-Pit were reviewed (see results dated July 27,
2000 and October 27, 2000). Baseline monitoring is being conducted for for selenium and
thallium. These elements reported slightly above standards in leach tests conducted for TR-001.
Significantly, the A-Pit water analyses provided thus far report well below the values reported
for the leach tests.
Upon evaluation of five quarters of baseline data, the Division will establish numeric protection
levels for the monitoring points. In accordance with groundwater protection requirements of the
Rules and Regulations, these levels will be established at the higher of either the water quality
use standard or the ambient condition.
As the pazameters thus monitored fall well below the drinking water and agricultural use
standards of 50 ug/L and 20 ug/L, respectively, it would appear that the operators request to set
NPL's at the State (WQCC) standards will be fulfilled by default. However, this will be
established only after considering all baseline results, some of which are forthcoming.

The operator should be providing the results of fourth and fith quarters baseline sampling in the
near future. Please let me know when these arrive so that I can evaluate the situation further.