REP29481

• Permit No: C1982056
• IBM Index Class Name: Report
• Doc Date: 3/1/2002
• Doc Name: 2000 AHR Responses to DMG Letter dated 3/15/01
• From: Twentymile Coal Company
• To: DMG
• Annual Report Year: 2000
• Permit Index Doc Type: Hydrology Report
• Media Type: D
• Archive: No

Mr. Tom Kaldenbach
February 21, 2002
Page Two
5. On Table 65C, the November values for average flow rate and cfs are in error. The
average flow rate value is actually 8.4 gpm, which equates to 0.019 cfs. Two (2) copies
of the revised Table are attached to substitute with the ones in your copies of the Foide]
Creek 2000 AHR.
6. Future AHRs will include flow information used to estimate upstream flows during
periods of limited access.
7. Site 109 is to be monitored for water level and field parameters quarterly and sampled for
water quality quarterly, if discharging. Two (2) copies of the revised text are attached to
substitute with the ones in your copies of the Foidel Creek 2000 AHR.
8. The underground gate road leading to 6 Right is scheduled to be sealed within the next
two months, thus, there will be no access to 6 Right for measuring inflow. However,
inflows in the 6 Right area will migrate downgradient to the northeast, and will be
reflected in the future inflow data of 10 Right.
9. What changes in mine discharge procedure does TCC propose to ensure that Fish Creek
does not exceed the suspect level of 1500 umhos/cm below mining operations ? In order
to quantify the predicted effect of sulfate contributions from sites 115 and 109, TCC in
association with a consultant, has developed a computer program -the "FCBH
Calculator". In the winter, when stream gauging is difficult, the FCBH Calculator uses
the flow and conductivity values from sites 69 (Trout Creek above Fish Creek
confluence) and 1005 (Trout Creek below Fish Creek confluence) to estimate the
appropriate discharge for sites 115 and/or 109. These same sites are also used to estimate
appropriate flow for site 109 in the summer. In the summer, the FCBH Calculator uses
measured flow and conductivity values from site 16A (upstream of discharge site 155),
and conductivity values from site 115 to calculate how much mine water, if any, may be
discharged from site 115. TCC uses these methods to manage controllable discharge
from sites 115 and 109, and avoid contributing to sulfate exceedences in Trout Creek.
10. An elevated concentration of total recoverable mercury was detected from a July 20,
2000 water sample obtained at Site 1005. DMG requests any data indicating
concentrations of mercury from the WMD sump area.
TCC examined mercury analytical data from additional sampling episodes for Site 1005
collected in 2000 and to date for 2001. In all cases mercury was reported to be below
detection limits (< 0.2 ugly. TCC also had the analytical laboratory reexamine there data
for this sampling, but found no discrepancies. TCC has no explanation for this anomaly.
TCC will continue to monitor this site as outlined in the subject permit.