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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MINE WATER MANAGEMENT AND
IMPACT ASSESSMENT
sanitary waste water. Or, it can be withdrawn for
dust suppression in the mine, in which case it then
becomes mine water.
The discussion of the mine water system and
hydrologic impact assessment is organized by the
four sources oC water:
• North Fork water
• sanitary wastewater
• mine water, and
• runoff from disturbed areas.
Use and discharge of water from these sources is
studied for its potential to affect the North Fork.
North Fork Water
During water year 1982, the conditional right to
withdraw water from the North Fork was deemed
absolute. When this water right is in priority, water
can be pumped from the intake point to the
freshwater storage pond(s) within the surface
facilities area. In average years, this water right is
expected to be out of priority from July to Septem-
ber. In 1977, it would have been out of priority
from April to September. In water year 1986,
WECC's Mt. Gunnison Pipeline water right met
quadrennial diligence for the conditional portion.
Accordingly, an additional portion was deemed
absolute by the Division 4 Water Court. That
decision brought the absolute portion to 0.88 cfs.
The 10-acre-toot capacity pond provides for water
storage during the term of permit; two ponds are
anticipated forsubsequent permit terms. Water can
also be stored in Sediment Ponds MB-1, MB-2,
and MB-3 under a separate decree. Storage is
usually limited to the maximum sediment level
elevation. Transfer to FW-1 is possible as outlined
in the M & R Plan. Average withdrawals are not
expected to exceed 50,000 gpd during the term of
permit and are likely to be on the order of 45,000
gpd, depending on production levels and require-
ments. During 1989 average withdrawal was
82.1 gpd Cor 250 working days.
Water from the freshwater pond(s) is used in two
ways. It can be treated to meet potable and sani-
tarywater requirements, used, and then treated as
WECC's Mt. Gunnison pipeline water rights were
out of priority during a portion of water year 1989
(from approximately 15 June through 30 Septem-
ber). Average daily low Oow in the North Fork
during water year 1989 was 54 cfs. The maximum
withdrawal at the intake is 450 gpm with both
pumps operating. This is Icss than 0.017 percent of
the observed average daily low Oow in the river
during the water year.
Sanitary Waste Water
The sanitary waste water treatment plant has been
operating since the fall of 1982. During water year
1989, discharge from the plant averaged 3208 gpd.
This discharge is approximately 0.0092 percent of
the average daily low Oow o[ 54 cfs observed in the
North Fork during the year.
Discharge monitoring results from the waste water
treatment plant, conducted under NPDES Permit
No. CO-0038776, are included in Appendix J. The
results of the analyses suggest the waste water
discharge has no measurable effect on water
quality in the North Fork Gunnison River.
Mine Water
Mine inflows during water year 1989 were small.
The total mine water inflow was 9.3 acre feet
during the year. The total water exiting the mine is
estimated to have been 13.2 acre feet.
The quality of mine water is considered good and
offers no problem for treatment and discharge.
Mine water was primarily discharged tram the
No.2 Portal. No discharges occurred from Syl-
vester Gulch.
Mine water inflow Cor water year 1990 is expected
to be similar to that experienced during water year
1989. Mine water is expected to have water quality
characteristics similar to that reported in Table 5.
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