2017-03-03_REVISION - M2012032 ‎(3)‎

• Permit No: M2012032
• IBM Index Class Name: REVISION
• Doc Date: 3/3/2017
• Doc Name: Adequacy Review - Preliminary
• From: Ouray Silver Mines
• To: DRMS
• Type & Sequence: TR9
• Email Name: THM
• Email Name: GRM
• Media Type: D
• Archive: No

V`
OLRaY SILVER MINES RECEIVED
MAR Q 3 2017
March 2, 2017 D!V!PoN of
l�ININv^�eCLAPdi,�TION
VIA U.S. Mail and Email "FETY
Colorado Division of Reclamation, Mining, & Safety
1313 Sherman Street, Rm. 215
Denver, CO 80203
Dear Mr. Marshall,
Ouray Silver Mines Inc. (OSMI) received the preliminary adequacy review(PAR) for Technical
Revision number 9 to Permit M2012-032 or the Revenue-Virginius Mine (Mine). TheFAR----"'
raised three major points, each o which is addressed below under headings that repeat the
DRMS point of clarification in italics.
1)Page 6 of 14 states that once the mill improvements are complete and operational OSMI will
sample various mill tailings and waste rock blends to determine what blend is most desirable
while remaining inert. Please commit to providing the DRMS with SPLP test results 30 days
prior to any material being sold for off-site use. Furthermore, variances in tailings composition
may occur over time, how often will the tailings be tested to insure the material remains inert?
OSMI requests that synthetic precipitation leaching procedure (SPLP) criteria be
established for the sale of a tailings/waste rock blend and that the criteria set to
groundwater standards. Setting criteria will allow for managing changing conditions
adaptively. Each batch of tailings/waste rock blend, weighing between 2,000 —5,000
tons, will be tested upon development and stockpiled for use or sale. Batches that do not
meet groundwater standards will be placed in the tailings facility. Results from SPLP
testing, along with a description of each batch, will be submitted with annual reports.
2) Please specify in greater detail the proposed water treatment for the mill discharge from the
lead and zinc thickeners. What types) of treatment will actually be implemented? What
equipment will need to be constructed/built to carry out this treatment? Is the proposed
treatment able to treat mill discharge to meet the requirements of the Colorado Department of
Public Health and Environments Regulation No. 41 Standards for Ground Water? In order to
approve this technical revision this information must be provided.
OSMI has engaged Barr Engineer to complete final engineering. Confirmatory
metallurgical testing is also ongoing with FLSmidth. Though samples were collected in
2016, OSMI believes that confirmatory testing is required during final Metallurgical
work. Samples of various proposed effluent streams to be treated are being collected
during this process. Based on pilot testing thus far, the Mill discharge is expected to
PO Box 564, 1900 Main Street, Unit 1, Ouray, Colorado,USA 81427
Tel. [phone] — Fax. [phone]