REP01431

• Permit No: C1980007
• IBM Index Class Name: Report
• Doc Date: 5/5/1995
• Doc Name: 1994 ANNUAL HYDROLOGY REPORT
• Annual Report Year: 1994
• Permit Index Doc Type: HYDROLOGY REPORT
• Media Type: D
• Archive: No

•

1.0 NyNologic Monitonrtg Activiner
The MB-1 and MB-2R dischazges were
tested for pH, total suspended solids, total
dissolved solids, and total iron. Results of
the analyses are shown on Table 1.5-1.
1.8 RUNOFF FROM
DISTURBED AREAS
Flowmeters are installed on discharge points
from sediment ponds which dischazge inter-
mittently to continuously record flows.
Information on flows, sampling points, and
quality of water discharged from the mine
site sediment ponds during WY 1994 is
included in Appendix J.
Overland runoff from snowmelt and
precipitation within the disturbed areas was
routed to one of five sediment ponds on the
mine site in WY 1994. The five sediment
ponds aze designed to contain the predicted
runoff from a statistically determined 10-
yeaz, 24-hour precipitation event, as well as
a calculated sediment storage volume. The
three larger ponds (MB-1, M$-2R and
MB3) have additional volume for Mountain
Coal Company's storage water rights. The
ponds are also designed to pass the overflow
from a 25-year, 24-hour precipitation event
safely.
The West Elk Mine site receives much of its
annual precipitation from snowfall during
the winter months. When warmer weather
begins in late February, Mazch or April,
most runoff to the sediment ponds is from
snowmelt. It is entirely possible for a
volume of runoff greater than the 10-year,
24-hour precipitation event to result from
snowmelt or snowmelt coupled with a small
precipitation event.
1.9 REFUSE PILE WATER
QUALITY
Water monitoring adjacent to the Lower
Refuse Pile consists of the monitoring of
alluvial wells around the refuse pile and
periodic sampling of discharges from MB-
2R. Pond MB-2R treats surface water
runoff from the refuse pile and adjacent
disturbed areas and any discharge from the
underdrain. Historic groundwater quality
data from wells SG-1, GP-1, GP-3, GP-4,
and GP-5 are incorporated into the data
tables found in Appendix H. Quality
parameters of Pond MB-2R discharge aze
presented in Table 2.41 and Table J-1,
Appendix J.
The sediment ponds are typically treated
with cationic flocculen[ when necessary to
speed clarification and settling of suspended
solids. Al] ponds, MB-1, MB-2R, MB-3,
MB-4 and MB-5 have manually controlled
dewatering devices. Ponds MB-1, MB-2R
and MB-5 aze dewatered intermittently with
the highest flows coming during eazly spring
runoff. Pond MB-5 is responsive to a high
spring groundwater table and sometimes has
to be dewatered more often. Dewatering
procedures take usually less than one day for
all ponds except MB-5.
R 1.210/IOA/OS/OS/95(9.04am1
17 REMISED 10.02/96