2019-09-16_REVISION - M1994117 ‎(2)‎

• Permit No: M1994117
• IBM Index Class Name: REVISION
• Doc Date: 9/16/2019
• Doc Name: Adequacy Review Response
• From: Colorado Milling Company
• To: DRMS
• Email Name: AME
• Media Type: D
• Archive: No

this pumping test, since all of the underground mine workings where water is stored are located
on patented mining claims owned by CMC.
c. Please be advised, submittal of the requested mine pool drawdown plan will be a stipulation
of AMO 1 approval, requiring this plan be submitted in the form of a Technical Revision for
Division review and approval, prior to mill operations commencing at the site. Please
acknowledge your acceptance of this stipulation.
CMC Response: CMC acknowledges that a mine pool drawdown plan will be a stipulation of
Revision AM 01 approval,requiring that this plan be submitted in the form of a Technical Revision
for DRMS review and approval,prior to milling operations commencing at the Gold Hill Millsite.
2) The operator's response to Item no. 1(d) states the operator is awaiting the results of the
Deere & Ault's mine pool control plan and monitoring plan to determine if it is necessary to
maintain the water levels in the mine workings below the design standard for the Times Mine
Bulkhead.
Please be advised, until the Division has reviewed and approved the new engineer bulkhead
evaluation based on the results of the proposed pumping test, and including different
recommendations than those included in the evaluation submitted to the Division on May 17,
2019, the operator must commit to maintaining water levels in the mine workings below the
design standard for the bulkhead, 17.6 feet of head or an elevation of 8,360 feet during
operations, including weekly monitoring of water levels.
CMC Response: CMC commits to maintaining water levels in the mine workings at an elevation
of 8,360 feet during operations until the DRMS has reviewed and approved the new bulkhead
evaluation based on the results of the proposed pumping test, which may include different
recommendations than those included in the Deere & Ault Consultants evaluation of the Times
Mine Bulkhead submitted on May 17,2019. CMC commits to conduct weekly monitoring of water
levels during operations.
3) The operator's response to Item no. 1(e) states the operator is awaiting the results of the Deer
& Ault's mine pool control plan and monitoring plan to determine the actual Times Mine
Bulkhead pressure and the effects of different water levels in the Times and Wynona Mines on
the bulkhead pressure.
Please be advised, until the Division has reviewed and approved the new engineer bulkhead
evaluation based on the results of the proposed pumping test, and including different
recommendations than those included in the evaluation submitted to the Division on May 17,
2019, the operator must commit to maintaining the bulkhead pressure below the design standard
3