REP30039

• Permit No: C1981022
• IBM Index Class Name: Report
• Doc Date: 8/27/1992
• Doc Name: Monitoring plan
• From: DMG
• To: STEVE SHUEY
• Permit Index Doc Type: Hydrology Report
• Media Type: D
• Archive: No

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August 27, 1992
2. NPDES outfall 011 is a ne~.a source. Therefore, the CDH required
that the operator monitor, in addition to other parameters, 011 for iS5 and
Total Iron weekly. Additionally, the operater must have at least 12 sample
results before requesting a reduciton in monitoring frequency. Because
discharge began during 1992 at 011, the Division may want to verify that the
prescribed monitoring plan has thus far been followed. See tables VI-4 and
permit for complete NPDES monitoring requirements.
Water Oualitv. Flow or Level Predictio
The operator contends that neither the inactive Somerset Mine nor the recently
activated Sanborn Creek Mine will significantly degrade the quality or
quantity of ground or surface water.
The operator maintains that the primary impact, if any, on NFGR will be on its
total dissolved solids (TDS) concentration. Based on historical data and low
flow conditions, the operator predicts TDS levels in NFGR to rise from a
baseline level 151 mg/1 (TDS avg. 1981) to around 300 mg/1 when water from
both the Somerset Creek Mine discharge to NFGR.
Historical date and monitoring during 1991 concurs with the operator's
predicted TDS levels.
The above prediction was based on conditions without inflow from the Rawlins
Sandstone aquifer to the "B" coal seam in the Sanborn Creek Mine. The
operator committed to a mine inflow study of the "B" Coal seam by the end of
1992.
The following comments pertain to Predictions
1. The 1991 AHR revealed flow in all drainages to reflect seasonal
variations and were not adversely impacted by mining activities.
2. Ground water levels in Somerset wells 6-6 and H-10 did not stablize
in 1991.
3. Should water levels in the Somerset mine workings exceed an unknown
threshold level, portal discharges may occur.Such an event would add creedance
to establishing a monitoring site downstream of the Somerset permit boundary
on NFGR as outlined previously.
4. The operator completed an inflow study of the "C" coal seam in
March of 1992 revealing inflow of 17 gmp and low TDS le•ie1; (300 mg;l).
5. The inflow study of the "B" coal seam yet to be completed may
necessitate a revision of predicted NFGR TDS level;. 8.5 feet of shale
separates Rawlins Sandstone Aquifer which exhibits TDS levels in excess of
7000 mg/1 (See SC-1 and SC-2 datea in 1991 AHR) from the "B" coal seam. Shale
is normally as excellent aquiclude but shculd inflow emanating from faults and
fractures in the Shale Stratum prove significant and requiie the ooerator to
discharge such water into sediment ponds and eventually PIFGR tds 1?eels may