REV06564

• Permit No: C1980005
• IBM Index Class Name: Revision
• Doc Date: 3/23/2007
• Doc Name: Proposed Decision & Findings of Compliance RN5
• From: DRMS
• To: Seneca Coal Company
• Type & Sequence: RN5
• Media Type: D
• Archive: No

Pit disturbance in the drainage has resulted in perennial flow at S W-S2-6, with a yeaz
round average of 0.481 cfs (up until the time that monitoring was discontinued at this
location). Flows at Pond 004 have decreased over time, but discharge remains perennial
through 2006.
Total dissolved solids in Cow Camp Creek have escalated as mining in the drainage
area has progressed. TDS has increased from an average of 600 mg/1 in 1982 at S W-
52-6 to an average of 3,170 mg/l in 2006 at Pond 004. Concentrations of sulfate,
calcium, and magnesium have increased in similaz proportion, while sodium and
bicazbonate concentrations have decreased.
Bond Creek
Mining in the Bond Creek drainage began in 1988. Data obtained at the outfall of Pond
008 show an increase in flows in Bond Creek over the last nine years. Mean annual
flow in 1987 was .028 cfs, and in 2002 was 0.107 cfs. Concentrations oftotal dissolved
solids have increased steadily during the past eleven yeazs, from 1,367 mg/1 in 1991 to
3,360 mg/1 in 2006.
Fish Creek is monitored at site SW-S2-13, downstream of the confluences of Bond
Creek and Cow Camp Creek with Fish Creek. Data from the site does not show any
identifiable change in water quality or quantity when compared with Fish Creek site
5W-S2-11, upstream of Bond Creek and Cow Camp Creek.
Effects of Mining on Surface Water
Changes in the quantity of water to the prevailing hydrologic balance are primarily due
to the location and timing of flows. It is difficult to define any changes due to mining in
the Grassy Creek basin because baseline data collected in 1980 include the influence of
12 yeazs of previous mining activity at Seneca II Mine. The Fish Creek drainage,
however, does indicate a change in the ground and surface water systems. Mining has
increased the amount of ground water available to be discharged into the surface water
system, due to discharging spoil aquifers. Cow Camp Creek now
exhibits perennial stream flow as a result of mining in this drainage whereas prior to
mining the creek ephemeral stream flow conditions existed.
Data are insufficient to demonstrate whether short term decreases in stream flow are due
to initial filling of ponds and resaturation of backfilled spoils. However, it is apparent
that any depletion is extremely short-lived. Variability in annual amounts of
precipitation supplied to the watershed makes it difficult to assess short term changes;
however, long-term changes in flow are expected to be minimal.
Three primary impacts on surface water quality were identified: 1) increased erosion
and sediment yield; 2) exceedences of applicable water quality standazds; and, 3)
increased total dissolved solids loading.
23