2016-10-05_REVISION - C1981008 ‎(4)‎

• Permit No: C1981008
• IBM Index Class Name: Revision
• Doc Date: 10/5/2016
• Doc Name: Adequacy Review to file Memo
• From: Tabetha Lynch
• To: File
• Type & Sequence: TR74
• Email Name: TNL
• Email Name: DIH
• Media Type: D
• Archive: No

COLORADO
Division of Reclamation,
Mining and Safety
Department of Natural Resources
1313 Sherman Street, Room 215
Denver, CO 80203
October 5, 2016
To: TR74 File
From: Tabetha Lynch
RE: New Horizon Mine, C-1981-008
TR -74, Adequacy Review Memo
Technical Revision No. 74 was submitted to propose the installation of nine monitoring wells in the
backfilled pits at the New Horizon Mine in areas upgradient of the Trench Drain. TR -74 also requested an
extension to the 180 day requirement for completion of rough backfilling and grading in accordance with
regulation 4.14.1(1)(c). This revision did not propose an increase in disturbed area but did result in an
increase in reclamation bond liability of $768.29 to seal and reclaim the monitoring wells.
The revision replaced 2.05.4(2)(d) page 1, replace 2.05.6(3) Cover, TOC, and pages 1-40, added
Attachment 2.05.6(3)-4 pages 1-2, and added Figure 2.05.6(3)-1 Backfill Monitoring Wells maps.
Per discussion with the operator:
In 2014, a trench drain was installed along the end wall of the final pit and the pit floor to capture
and route a spoil spring with a significant flow to one collection point just below the outlet of Pond
013. These nine monitoring wells are being installed to evaluate water quality, direction of
groundwater flow, and saturated thickness in the backfilled pit to help us further define the extent of
the spoil spring and what is influencing it etc. Ultimately, the operator is nstalling these wells and
acquiring data to assist them on how or if they will treat the spoil spring water for the long term
dependent on what CDPHE-WQCD requires long term. Also, please see page 18 of Section
2.05.6(3) and page 2 of Attachment 2.05.6(3)-4.
These wells are not intended to be a part of the approved hydrological monitoring program included
in Section 2.04.7 of the PAP to determine or verify the PHC for the site. They are intended to be
specially for the mine to acquire additional data as it relates to define the spoil spring. The backfill
monitoring wells are not intended to be a part of the approved hydrological monitoring program
included in Section 2.04.7 of the PAP. Therefore, they have not been shown on Map 2.04.7-1A.
However, Figure 2.05.6(3)-1 has been included as part of Attachment 2.05.6(3)-4 to show the
location of the nine monitoring wells.
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1313 Sherman Street, Room 215, Denver, CO 80203 P 303.866.3567 F 303.832.8106 http://mining.state.co.us
John W. Hickenlooper, Governor I Mike King, Executive Director I Virginia Brannon, Director