2014-01-22_REVISION - M1977493

• Permit No: M1977493
• IBM Index Class Name: REVISION
• Doc Date: 1/22/2014
• Doc Name: Addendum to TR22
• From: Climax Molybdenum
• To: DRMS
• Type & Sequence: TR22
• Email Name: ECS
• Media Type: D
• Archive: No

Climax Molybdenum
A Freeport- McMoRan Company
Date:
Memo To:
From:
Re:
January 17, 2014
Raymond Lazuk, Environmental Manager
Chris Schmitz, Chief Mine Engineer
Underground Mine Material Disposal and OSF Stability
Climax Mine
Hwy 91 — Fremont Pass
Climax, CO 80429
Phone [phone]
Fax [phone]
This memo is in response to your request for our mine geotechnical engineering staff to evaluate the
amount of underground waste that is expected to be encountered during open pit mining at Climax,
and the potential effects of mixing this material with other waste rock that is deposited in our
overburden stockpile facilities (OSFs). Based on our best professional judgment, given the very
small volume of mixed waste material relative to the overall volume of waste rock to be mined at
Climax, we do not believe that the mixed waste rock material will create any stability concerns
above those normally expected with unmixed waste rock.
We examined the types of underground materials likely to be encountered during the life of the mine
and estimated that there would be approximately 766,987 tons of underground materials as follows:
Concrete:
763,674 tons
Steel Rails:
1,317 tons
Wood Ties:
1,996 tons
These materials would comprise about 5.9% of the total expected 13,000,000 tons of mixed waste
rock that is blasted and mined from the former underground areas within the pit. Most of this
underground material is concrete, which would not behave any differently than waste rock. Only an
estimated 0.025% of the total 13,000,000 tons of mixed waste is steel or wood (rails and ties). If we
were to double that percentage to account for other steel or wood such as cribbing, rock bolts and
shotcrete mesh, there would still only be 0.050% of wood and steel in the 13,000,000 tons going to
the OSFs.
Climax anticipates mining approximately 262,660,000 tons of waste rock under the current life of
mine plan. If we were to calculate the underground wood and steel as a percentage of total material
in the OSFs, the doubled estimate of 0.050% becomes 0.0025% of the total 262,600,000 tons of
waste rock.
This very small amount of steel and wood, relative to the overall content of the OSF would not
materially affect the stability of the stockpile. To further eliminate any stability concerns, it is
recommended that the mixed waste rock and underground material not be segregated from other
waste rock so that it is more dispersed within the OSF.