HYDRO25324

• Permit No: M1988112
• IBM Index Class Name: Hydrology
• Doc Date: 12/22/2000
• Doc Name: MEMO NOTICE OF ISSUANCE OF THE PERMIT FOR BATTLE MTN GOLD CO-0045675
• From: CDPHE
• To: ATTENDEES AT THE PUBLIC MEETING ON THE BATTLE MTN PERMIT CO-0045675
• Media Type: D
• Archive: No

Page 3~
COLORADO DEPARTMENT OF HEALTH, Water Quality Control Division
Rationale -Page 36 Permtt No. CO-0045675
no longer applicable. The tiered-discharge approach for Discharge Point 00 f provides the flexibility necessary fo
reasonably represent the probable range of flows that are expected to occur during the extraction ofgroundwater from the
West Pit. For the purposes of the CDPS permit, BMRI will pump the backfilled West Pit as necessary, up to a maximum
flow rate 01400 gpm (30 day average), to maintain a reversed hydraulic gradient from the Rilo Seco alluvial aquifer to the
West Pit.
Vlll. CHANGES TO PERMIT AND RATIONALE FOLLOWING PUBLIC NOTICE
First Public Notice Period, Comment Letters and First Public Meeting: (Cont.J:
Responses to Comment Letters: (Coot)
Comments: Issues related to outta11002:
- Better definitions for the location and requirements for out(all 002
- Utilizing mondodng wells to define outtall 002
- Addressing speck flow and other limdatlons and monitoring requirements for out(all 002
- Identifying seepage contributions as part of the mass balance water quality standard-based calculations
- Not referencing the CDMG requirements (or TR-28 and TR-28 in association with the requirements for outtall
CDPS discharge permit
- Concems related to short-term West Pit groundwater discharge issues and long-term water groundwater disc
(defining a window for identfication of ground water flowing through a restricted zone as paints of compliance;
utilization of additional ground water monitoring wells; installation o(a slurry wall)
- Concems regarding the Best Management Practices requirements described (or outta11002
Response:
There were a number ofcomments related to oudall 002. In response to these comments, several major revisions were
made relating to outtall 002. Descriptive language, as well as figure 2 of the permit, have been revised to define the
window and boundary for 002. Also, a limitation that is associated with this outtall has been added in the permit which
defines 002 with respect fo maintaining a required water level depth in the West Pit [hat is below the water level of tho Rito
Seco to ensure that the hydraulic gradient is reversed resulting in permanent elimination of flow from the West PR to the
seeps on the bank o(the Rito Seco. A compliance schedule has also been incorporated and the Best Management
Practices requirements for this outfall have been revised in the permit to further address the existing situation. Refer to the
revisions (or 002 and the compliance schedule in the permit (Part I.A. S) and rationale (Sections I1.F, IVA.1. and VI.A.2) for
further in(ormab'on, as well as additional discussions relating to comments and responses for ouda11002 in Appendix D of
the rationale.
Comments: Including additional outfalls (or discharge points), limtts, and mon8odng for the (our surface seeps; ensuring
that the seeps are contained and will not discharge to surface waters
Response:
No additional outtalls need to be identired in this permit (or the (our historic surface seeps, since there has not been Row in
any of the odginal seep locations since February 8, 2000. This issue is further discussed in pages 6, 8 and 9 ofAppondix
D.
Comments: Other Groundwater Related Issues:
- Concems with the mining operation and reclamation acbvibes impacting the ground water hydrology in the ~
- Impacts upon wells downgredient of the facility
- Indica8ons of locations o(ddnking water sources in the vicinity (Shalom Ranch, San Luis alluvial wells, etc.)
Response:
Issues relating to groundwater are addressed in the Colorado Division of Minerals and Geology (CDMG) mining permit for
this Iacildy, since impacts to groundwater from the mining operation are under the judsdiction of that agency. Further
information is included in the General Comments (page 23), as well as in comments and responses related to groundwater
on pages 8-10 olAppendix D.
In addrYion, with protection of surface water quality standards through compliance with the limitations for this permit, the
applicable groundwater standards would also be protected.
An indication of the Concems relating to the locations o(the downgradient alluvla4groundwater drinking water sources
(wells) have been included in that portion o/the rationale.