ENFORCE37735

• Permit No: C1982056
• IBM Index Class Name: Enforcement
• Doc Date: 2/8/2007
• Doc Name: Abatement Completion Report for Abatement 10 and 11
• Violation No.: CV2006006
• Media Type: D
• Archive: No

Middle Creek) and 1005 (Trout Creek neaz Orten Ranch, below Fish Creek confluence, copies
attached for reference) indicate a minor increase in EC and TDS values for Foidel Creek, but no
• significant variance for Trout Creek, following the dischazge, with all values remaining within the
range of recent historical variance.. TSS values for Foidel Creek spiked at the time of the dischazge
to approximately 18mg/1, but by the second sampling (approximately one week later) had returned
to normal historical levels (approximately 5 to 7 mg/1). No significant change in TSS values was
noted for Trout Creek.
Sten 6c: Contain the coal fines discharge (10/03/061
The coal fines discharge was contained on 09/11/06 by the actions previously described for Steps
1 and 3. Abated 09!13/06.
Step 6d: Assess the notential toxicity imaacts, including the documentation of the chemical
constituency of the discharged material, to Foidel Creek and Trout Creek (10/03/061
The dischazge consisted solely of coal fines, water, and a flocculant. Neither the coal fines nor
water present any potential toxicity concerns. Potential toxicity of the flocculant was assessed
on 09/11/06 and 09/12/06 through review of the MSDS sheet for the flocculant used, and
through contacts with the flocculant manufacturer re: any potential aquatic toxicity (copies
of documentation provided to CDRMS and attached for reference). Potential aquatic toxicity was
also quantitatively assessed in the field by a CDOW Representative, who conducted spot
shocking surveys and visual observations of Foidel Creek above, at, and below the point of
discharge on 09/14/06. Fish and aquatics organisms were observed above the discharge point and
below the identified limit of coal fines migration. It is assumed that some dischazge-related
mortality of fish and aquatic species occurred within the Foidel Creek stream segment directly
• affected by coal fines deposition, due to deposition and elevated sediment levels. Abated
10/03/06.
Step 6e: Provide an estimate of the total slurry (water nlus solids volume) discharged to
Foidel Creek (10/13/061
The Thickener underflow line flows intermittently, but probably averages 80gpm of coal fines
slurry. Stream sampling was conducted on 09/06/06, and at that time, there was no evidence of
coal fines dischazge, so the maximum time period over which coal fines discharge could have
occurred is approximately 5 days (mid-day 09/06/06 through mid-day 09/11/06). Based on this
information, the maximum volume of coal fines slurry that could have discharged to Pond E is:
80 gpm x 60 m/hr x 24 hr/day x 5 days = 576,000 gallons or 1.8 acre-ft
The design sediment storage capacity for Pond E is 2.0 acre-ft and, based on recent cleaning and
observations, sediment accumulations (primarily neaz the pond inlet) had filled approximately 1/3
(0.66 acre-ft) of the available storage capacity. Subtracting the remaining available sediment
storage capacity (2.0 acre-ft - 0.66 acre-ft = 1.34 acre-ft) from the calculated discharge volume to
Pond E (1.8 acre-ft), results in an estimated coal slurry discharge to Foidel Creek of
approximately 0.46 acre-ft or 20,000 ft't or 740 cy. Given that the coal fines slurry is
approximately 25 percent solids, the coal fines solids volume discharged to, and potentially
deposited, in Foidel Creek is estimated at 185 cy.
• Step 6f: Submit a written reuort of this information to the Division (10/13/06)
The reporting requirements for Abatement Step 6f were addressed by submittal of an
Abatement Report on 10/13/06.
NOV CV-2006-006 Abatement Report 6 2/7/2007