REP13703

• Permit No: C1982057
• IBM Index Class Name: Report
• Doc Date: 1/5/1998
• Doc Name: SENECA II-W MINE C-82-057 1996 ANNUAL HYDROLOGY REPORT ANNUAL RECLAMATION REPORT
• From: DMG
• To: SENECA COAL CO
• Permit Index Doc Type: HYDROLOGY REPORT
• Media Type: D
• Archive: No

III IIIIIIIIIIIII III
999
STATE OF COLORt~DO
DIVISION OE MINERALS AND GEOLOGY
DepanmeN of Natural Resources
1713 Sherman St., Room 215 Ilye
Denver, Colorario 80203 Ily
Phune: (3031 866-3567
FAX. [phone]
DEPARTNIEfYT OF
NATURAL
RESOURCES
Roy Romer
Governor
January 5, ] 998 lames 5. Lochhead
ErecW rvc DirPCbr
Mr. Michael G. Altavilla "'i`h'e~ a. `°°F
Division Direclw
Seneca Coal Company
P.O. Drawer D
Hayden, CO 81639
RE: Seneca II-W Mine (C-82-057)
1996 Annual Hydrology Report & Annual Reclamation Report
The Division of Minerals and Geology received the 1996 Annual Hydrology Report (AHR) and
Annual Reclamation Report (ARR) for the Seneca II-W Mine on March 3, 1997 and April 4,
1997, respectively.
The ARR was submitted and is in compliance with Rule 2.04.13. The Division has no comments
that need to be addressed by the operator.
The AHR was found to be ahigh-quality document, containing the necessary information for
analysis. The AHR could be improved by two means. First, Seneca could relate the results to
the PHC section of the permit and second, Seneca could use the same scale on the plots where
possible. Some are way out of the range of others, but for our purposes, vaziation in TDS content
of 100 mg/I at a given sampling location is not significant compared to variations of 2 or 3 orders
of magnitude, the range over which we are observing changes at some locations.
The Division has a few comments regarding the conformance of the hydrologic system to the
predictions in the PHC;
Surface Water
The quality of the water in the Hubberson Gulch "system" and the Dry Creek "system" have not
reached the high dissolved salts levels predicted in the permit. At Hubberson Gulch, the water
downstream of NPDES point 006 has increased about 250 mg/1, but has reached a maximum on
one occasion of only 1700 mg/I, much less than the predicted post-mining concentration of 2200
mg/l. Most measurements indicate levels about 830 mg/I. At Dry Creek, the NPDES discharge
point has seen water increase from 1100 mgJl to nearly 1500 mgll, but at the monitoring site
downstream of the confluence of that tributary with Dry Creek, the measurements have fallen
within the historic range, 1000 mg/I less than predicted.