2011-08-15_REVISION - M1990057 ‎(5)‎

• Permit No: M1990057
• IBM Index Class Name: REVISION
• Doc Date: 8/15/2011
• Doc Name: Letter of Clarification
• From: The Union Milling Company
• To: DRMS
• Type & Sequence: TR3
• Email Name: MAC
• Media Type: D
• Archive: No

August 15, 2011
Mr. Michael Cunningham
Environmental Protection Specialist
Division of Reclamation, Mining and Safety
Department of Natural Resources
1313 Sherman Street, Room 215
Denver, CO 80203
Re: Permit M1990 -057, Letter of Clarification, TR #3
Dear Mr. Cunningham,
The Union Milling Company
6200 S. Vivian St.
Littleton, CO 80127
+1.303.947.3499
RECtiVED
AUU 1 5 2011
Division €f Reclamation
Mining & Safety
Union Milling Company (UMC) is responding to the Division's request to provide a Letter of
Clarification (Letter) with regard to Technical Revision #3 (TR), currently on extension until August 15,
2011. On Thursday, August 11, 2011, UMC, Calais Resources, and the Division met and discussed the
status of the TR review. UMC concurs with the Division that the TR encompasses a multifaceted
submission of regulatory issues, operational changes and longer term operational phases, all of varying
criticality. In the interest of expediting the approval of the critical issues addressed by the TR, UMC is
submitting this Letter addressing the immediate issues, as discussed in the meeting.
UMC holds an active permit, with stipulations. The primary and /or critical purpose of the TR submittal is
the removal, through compliance or mitigation, of the stipulations. The stipulations are listed below.
1) Submission to the Division of correspondence with the State Engineers Office regarding water
rights.
2) Submission to the Division of correspondence with the Colorado Air Quality Control Division
regarding an air permit.
3) Submission to the Division of quarterly water samples from tailings effluent.
4) Surface water diversions will be sized to convey the flow from a 25yr -24hr or 25yr -6hr storm,
whichever is greater.
5) Construction of an earth liner in the tailings impoundment of materials with permeabilities less
than or equal to 2ft per year with a minimum of 12in of suitable material should be compacted to
a 95% Proctor Density.
UMC requests the Division approve the mitigation and remove stipulations 1, 2 and 3 as discussed below
and as discussed in the TR submittal. UMC also requests Division approval for UMC to proceed with the
construction of the TSF facility to satisfy compliance with stipulation 5.
UMC will supply to the Division the requisite EPP construction documents following completion of the
TSF to demonstrate compliance and mitigation of stipulation 5. UMC will concurrently submit a
Stormwater Management Plan (SWMP) General Permit and as -built disturbed area surface water
diversion calculations as compliance with stipulation 4.