HYDRO26197

• Permit No: C1980007
• IBM Index Class Name: Hydrology
• Doc Name: APPENDIX A ISOTOPE ANALYTICAL LABORATORY REPORTS
• Permit Index Doc Type: OTHER GROUND WATER
• Media Type: D
• Archive: No

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GEOCHRON LABORATORIES
a division of Krueger Enterprises, Inc.
711 CONCORD AVENUE • CAMBRIDGE, MASSACHUSETTS 02138-1002 • U . S . A
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RADIOCARBON AGE DETERMINATION REPORT OF ANALYTICAL WORK
Our Sample No. GX-24795-PRI Date Received: 10/30/98
Your Reference: Mountain Coal Company/West Elk Mine Date Reported: 1 1 /21 /9 8
Submitted by: Mr. Erik C. Petersen
Mayo & Associates
710 East 100 North
Lindon, Utah 84042
Sample Name: West Elk Mine: G-26C
AGE = 2,770 t 400 1<C years BP (13C corrected).
(70.85 t 3.55) °~ of the modern (1950) 14C activity.
Description: Sample of groundwater precipitate.
Pretreatment: The barium salt precipitate was rapidly vacuum filtered and immediately hydrolyzed,
under vacuum, to recover carbon dioxide from the barium carbonates for the analysis.
13C analysis was made on a small portion of the same evolved gas.
Comments:
S13C+PDB = -9.9 X.
Notes: This date is based upon the Libby half life (5570 years) for 14C. The error stated is t 1a as judged by
the analytical data alone. Our modern standard is 95% of the activity of N.B.S. Oxalic Acid.
The age is referenced to the year A.D. 1950.
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SPECIALISTS IN GEOCHRONOLOGY 8 ISOTOPE GEOLOGY