2017-03-08_REPORT - M1977493

• Permit No: M1977493
• IBM Index Class Name: Report
• Doc Date: 3/8/2017
• Doc Name: Annual Fee/Report/Map
• From: Climax Molybdenum Company
• To: DRMS
• Annual Report Year: 2017
• Email Name: ECS
• Media Type: D
• Archive: No

A.!TC0M AECOM 303-694 2770 tel
6200 S Quebec St 303 694 3946 fax
Greenwood Village,CO 80111
www.aecom.com
February 20, 2017
Mr. Raymond Lazuk
Environmental Manager
Climax Molybdenum Company-Climax Mine
Highway 91 —Fremont Pass
Climax, CO 80429
Subject: DRMS Annual (Year 2016) Tailing Storage Facility Evaluation, Tenmile and
Mayflower Tailings Storage Facilities, Climax Mine, Permit No. M-1977-493
Dear Mr. Lazuk:
URS Corporation, a legacy company of AECOM, serves as the Engineer of Record (EOR) for the
Tenmile and Mayflower Tailings Storage Facilitates (TSF)at the Climax Mine, near Fremont pass
Colorado. AECOM has prepared this summary of our Annual (2016) TSF Evaluation as required by
Section 6 of the Mayflower TSF Operations and Maintenance Manual (OMM) and as stated in the
response letter dated June 23, 2014 from Climax Molydenum Company to the Division of
Reclamation, Mining, and Safety (DRMS):
DRMS initially requested that the annual TSF inspection/evaluation/certification report be
submitted to DRMS within 30 working days of the inspection. Climax has requested that the
report be included with the standard annual report for the site. DRMS will allow the submittal
of the TSF certification report with the other annual report if Climax will commit to notifying
DRMS within 30 days of the inspection(or sooner if possible) of any issues identified in the
inspection report that require corrective actions or modification to the existing approved TSF
plans.
It is our understanding you will include this annual letter to DRMS in compliance with your other
annual reporting. Presented below is a summary of key observations made during 2016.
Active deposition in 2016 occurred at the Tenmile TSF with leadoffs in January, February, March,
November and December and with spigots September and October. Tailing deposition at Mayflower
TSF in 2016 occurred through the leadoffs or cutouts in March, April, May, July, and September, and
with spigots June, July, August and September.
AECOM completed monthly site inspections of the active TSF(s)from June to October 2016. The
review included meeting with operations personnel and reviewing production and operational
logistics, operational plans, tailing management challenges, and future plans for operating the dams.
Our site visits included reviewing tailing dam instrumentation, specifically reviewing piezometric
elevations. We also completed a monthly walking tour of the dam observing the active and inactive
tailing beach, dam crest, abutments, downstream slope, and toe area. We also conducted a review
of the horizontal and foundation drain outfalls, as accessible and applicable.
M:\DCS\TEMPORARY\MELISSA\2016 TSF ANNUAL REVIEW.DOCX