2021-08-17_REVISION - M1977342

• Permit No: M1977342
• IBM Index Class Name: Revision
• Doc Date: 8/17/2021
• Doc Name: Adequacy Review Response
• From: Climax Molybdenum Company
• To: DRMS
• Type & Sequence: TR34
• Email Name: PSH
• Email Name: JLE
• Media Type: D
• Archive: No

Mr. Peter Hays
TR-34—Environmental Protection Plan, Adequacy Review Response
August 12, 2021
In addition to the above items, Henderson has also addressed items 7 and 8 per your related email
requests on July 22, 2021. Your comments are included below in italics, followed by Henderson's
response. Item 9 relates to a recent adjustment to Nokes dosing.
7. The description of the function of J Pond at the URAD WTP in the revised EPP differs from what
we discussed in the field. Please review the wording for the J Pond description on page 15 of the
revised EPP to verify the wording is accurate.
Henderson has revised the last paragraph of Section 7.1.1 - Mine EPF 1.1 — Mine Water& URAD
Water Treatment System (Page 18) of the EPP to clarify the function of J Pond.
8. The revised EPP states, "A stormwater diversion system has been constructed on the south side
of the Mine office and surface operations to divert un-impacted stormwater around industrial
activities to the east end of the property." on page 22 and "Diversion ditches have been
constructed on the south side of the Mine office and surface operations to divert water around
industrial activities to the east end of the property."on page 36.
Please confirm the ditch conveys water from Butler Gulch east to the West Fork of Clear Creek.
It appeared during the inspection the old adit was the diversion point for the ditch with water
flowing from the adit west to Butler Gulch and east to Clear Creek. Please confirm the flow
direction(s) and update the EPP accordingly.
Henderson has revised the first paragraph of Section 7.1.1 - Mine EPF 1.2 — Stormwater
Diversion System (Page 18) and the last bullet in Section 10.1 (Page 34) of the EPP to confirm
flow directions within the diversion ditch.
9. Henderson identified an issue with the Nokes dosing calculations during a recent review. As
such, the dosing rate has been updated in Table 5-2: Designated Chemicals Used at the
Henderson Mill of the EPP from 0.2 Ibs/ton to 0.6 Ibs/ton.
Included with this submittal are two compiled pdfs:
• Henderson Adequacy Review Response - The specific EPP pages and Figures that have been
revised, SDSs for new designated chemicals, Mine and Mill SWMPs and the IRM Table of
contents, as noted above.
• Henderson EPP Complete -As a convenience, a complete EPP package with all new information
incorporated.
If you have any questions regarding this submittal, please contact me at [phone].
Sincerely,
Miguel Hamarat
Environmental Manager
Climax Molybdenum Company
Henderson Operations
Enclosures:
1. Henderson Adequacy Review Response (compiled pdf)
2. Henderson EPP Complete (compiled pdo
cc(via email)
G. Niggeler, Climax
Page 3