2015-07-21_REVISION - C1982056 ‎(2)‎

• Permit No: C1982056
• IBM Index Class Name: Revision
• Doc Date: 7/21/2015
• Doc Name: Adequacy Review No. 3
• From: DRMS
• To: Twentymile Coal Company
• Type & Sequence: PR10
• Email Name: JLE
• Email Name: DIH
• Media Type: D
• Archive: No

Twentymile Coal, LLC.
Page 14
July 21, 2015
considerations, very limited monitoring is considered necessary for the mining activities
proposed under PR10. A brief summary of the proposed monitoring is provided for
inclusion in Exhibit 4.
b. Division's Response:
i. Alluvial Well AVF15 is located above the 9 Right Long Wall Panel and is within
the affected area associated with mining in the WCR. Given this, it would be
appropriate to install a new downstream monitoring well outside of the affected
area to evaluate impacts to the Fish Creek Alluvium.
ii. Exhibit 4E-11 submitted with the response letter indicates wells 008AVF1 and
008AVF2 are downstream of the WCR mining area in the Foidel Creek alluvium.
The Division could not locate well 008AVFI on the 13a Map. Please revise this
map to depict the location of this well.
iii. Is there an upstream monitoring well for the Foidel Creek alluvium that would be
appropriate to use to monitor impacts related to mining in the WCR? Would well
009-S-10 be appropriate to use? If not, TC will need to revise the monitoring
plan and install an upstream well.
iv. Surface Water Site SW15 is located within the affected area associated with
mining in the WCR. Given this, it would be appropriate to install a new
downstream monitoring site outside of the affected area to evaluate impacts to
the Fish Creek surface water.
v. Site 900 appears to be upstream of the WCR affected area along Foidel Creek.
Given this, it would not serve as an appropriate downstream monitoring station
for Foidel Creek. Please revise the monitoring plan to monitor a site that is
downstream of the WCR affected area.
vi. The monitoring frequency for Site 8 and 900 do not match the monitoring
frequency currently approved in Exhibit 14 in the permit for these sites. Does
TC intend to conduct additional monitoring in accordance with the proposed plan
submitted with Exhibit 4E-11? If so, please revise the water monitoring plan
currently approved to match what is proposed in Exhibit 4E-11.
vii. Please revise the monitoring plan to indicate when the ponding and vegetation
monitoring plan will be suspended.
This concludes the Division's review of TC's response to our preliminary adequacy review and second
adequacy review letters. The decision date for PR10 is July 31St, 2015. If you need additional time to
address any remaining issues and any new issues identified in our review please request an extension of
the decision date. If you have any questions feel free to contact me at [phone], extension 8120.