2001-12-11_REPORT - C1980007

• Permit No: C1980007
• IBM Index Class Name: Report
• Doc Date: 12/11/2001
• Doc Name: AHR text
• Annual Report Year: 1989
• Permit Index Doc Type: Hydrology Report
• Media Type: D
• Archive: No

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Dora lnrerprcrarion wd lmpacr Assesstnmr for Permir Area and Adjacrnr Arcot
not appear to be a continuing problem. During
1989, both conductivity and TDS values were
within the ranges of baseline values.
Refuse pile monitoring wells GP-3 through GP-5
remained dry throughout water year 1989. Also,
there was no flow from the toe underdrain during
water year 1989. However, pond MB-6 collected
surface runoff from the refuse pile and can be
considered representative of refuse pile conditions.
A sample taken from MB-6 on 2 May 1989 indicat-
ed pH, conductivity, dissolved oxygen, turbidity,
TDS, TSS, iron, and manganese were 9.2,
2.09 mmhos/cm, 9.4 percent, 582, 1672 mg/I,
184 mg/I, 23.29 mg/I, and O.17 mg/I, respectively.
The amount of refuse material placed in the lower
refuse pile is highly dependant on conditions
encountered in the mine. Projected refuse produc-
tion for 1989 is approximately 50,000 tons from
"F" seam mining and 55,000 tons from "B" seam
slope development.
ASSESSMENT OF SPRINGS
A comparison of 1989 monitoring data with previ-
ous years shows no significant trends or changes
which can be associated with mining activity. Most
springs arc responsive to spring runoff, but Ilow
rates are sporadic and many times do not correlate
well with other seasonal parameters such as snow-
pack, precipitation, or streamflow.
ASSESSMENT OF SURFACE
WATER AND AVF'S
Efforts were made in previous annual reports to
characterize baseline river water quality. The
purpose was to evaluate potential changes in
surface water quality due to mining activities at the
Mt. Gunnison No. 1 Mine. Continuous monitoring
of stream flows and periodic monitoring of spring
discharge rates are performed to provide the long
term data base from which possible impacts of
mining can be assessed.
BASELINE CHARACTERIZATION OF
WATER QUALITY AND
STREAMFLOW
A baseline characterization of North Fork water
quality was performed in previous annual reports
to evaluate the potential changes in North Fork
water quality that could result from discharges at
the Mt. Gunnison No. 1 Mine. Baseline character-
ization was performed downstream of the mine
before the start of construction in August 1981.
Data sources were the USGS stream gauging
station on the North Fork near Somerset and the
West Elk Coal Co. water quality monitoring
station on the North Fork below the mine. Both
stations were downstream of the surface facilities
area and downstream of all discharge points.
Baseline data and analysis of these data are provid-
ed in the Mining and Reclamation Plan for the Mt.
Gunnison No. 1 Mine and in the first annual
hydrology report.
COMPARISON OF BASELINE WATER
QUALITY WITH OPERATIONAL
DATA
O(the ten parameters selected Car baseline charac-
terization, seasonal trends are apparent for TDS,
TSS, and total iron. The other parameters do not
exhibit seasonal variation. Total dissolved solids
are least concentrated in the North Fork during
the period between about May and July. The likely
reason for this pattern is during this period
high-TDS groundwater is diluted by snow runoff.
Total iron is most concentrated during this period.
Total suspended solids are most concentrated from
April to July.
A comparison of baseline water quality data in the
North Fork of the Gunnison River with 1989
monitoring data shows no significant changes in
water quality in the North Fork. No apparent
changes in the water quality of the North Fork of
the Gunnison River can be attributed to affects of
mining during water year 1989.
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