_REPORT - C1980007

• Permit No: C1980007
• IBM Index Class Name: Report
• Doc Name: ANNUAL HYDROLOGY REPORT MT GUNNISON NO 1 MINE WATER YEAR 1989
• Annual Report Year: 1989
• Permit Index Doc Type: Hydrology Report
• Media Type: D
• Archive: No

Hydrologic Dow Interpretation and Impact Awe ml for Penh Ama and Adjacmt Are=
not appear to be a continuing problem. During BASELINE CHARACTERIZATION OF
1989, both conductivity and TDS values were WATER QUALITY AND
within the ranges of baseline values. STREAMFLOW
Refuse pile monitoring wells GP-3 through GP-5
remained dry throughout water year 1989. Also, A baseline characterization of North Fork water
there was no Bow from the toe underdrain during quality was performed in previous annual reports
water year 1989. However, pond MB-6 collected to evaluate the potential changes in North Fork
surface runoff from the refuse pile and can be water quality that could result from discharges at
considered representative of refuse pile conditions. the Mt. Gunnison No. 1 Mine. Baseline character-
A sample taken from MB-6 on 2 May 1989 indicat- ization was performed downstream of the mine
ed pH, conductivity, dissolved oxygen, turbidity, before the start of construction in August 1981.
TDS, TSS, iron, and manganese were 9.2, Data sources were the USGS stream gauging
2.09 mmhos/cm, 9.4 percent, 582, 1672 mg/I, station on the North Fork near Somerset and the
184 mg/l, 23.29 mg/I, and 0.17 mg/I, respectively. West Elk Coal Co. water quality monitoring
station on the North Fork below the mine. Both
The amount of refuse material placed in the lower stations were downstream of the surface facilities
refuse pile is highly dependant on conditions area and downstream of all discharge points.
encountered in the mine. Projected refuse produc- Baseline data and analysis of these data are provid-
tion for 1989 is approximately 50,000 tons from ed in the Mining and Reclamation Plan for the Mi.
"F ' seam mining and 55,000 tons from "B" scam Gunnison No. 1 Mine and in the first annual
slope development, hydrology report.
ASSESSMENT OF SPRINGS COMPARISON OF BASELINE WATER
• QUALITY WITH OPERATIONAL
A comparison of 1989 monitoring data with previ- DATA
ous years shows no significant trends or changes
which can be associated with mining activity. Most Of the ten parameters selected for baseline charac-
springs are responsive to spring runoff, but Bow terization, seasonal trends are apparent for TDS,
rates are sporadic and many times do not correlate TSS, and total iron. The other parameters do not
well with other seasonal parameters such as snow- exhibit seasonal variation. Total dissolved solids
pack, precipitation, or streamllow. are least concentrated in the North Fork during
the period between about May and July.The likely
ASSESSMENT OF SURFACE reason for this pattern is during this period
high-TDS groundwater is diluted by snow runoff.
WATER AND AVF S Total iron is most concentrated during this period.
Total suspended solids are most concentrated from
Efforts were made in previous annual reports to April to July.
characterize baseline river water quality. The
purpose was to evaluate potential changes in A comparison of baseline water quality data in the
surface water quality due to mining activities at the North Fork of the Gunnison River with 1989
Mi.Gunnison No. 1 Mine.Continuous monitoring monitoring data shows no significant changes in
of stream Bows and periodic monitoring of spring water quality in the North Fork. No apparent
discharge rates are performed to provide the long changes in the water quality of the North Fork of
term data base from which possible impacts of the Gunnison River can be attributed to affects of
mining can be assessed. mining during water year 1989.
0
12