M1977342_AM8_AM-08 Henderson Rec Permit M-1977-342_72046

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1. INTRODUCTION Climax Molybdenum Company - Henderson Operations (Henderson) is an active molybdenum mining and milling operation wholly owned and operated by the Climax Molybdenum Company (CMC), which is a wholly owned subsidiary of Freeport-McMoRan Copper & Gold. Henderson began mining molybdenite ore and production of molybdenum disulfide concentrates in mid-1976. The Colorado Mined Land Reclamation Board (Board) approved the Mining and Reclamation Permit (Permit) required under the Colorado Mined Land Reclamation Act of 1976 (Act) in late 1977 (Permit No. M-1977-342). Subsequently, the Permit was formally amended in 1981 (AM- 01), 1996 (AM-02 -formally withdrawn), 1998 (AM-03), 2003 (AM-04), 2006 (AM-05 —formally withdrawn with the submittal of AM-06), 2007 (AM-06) and 2020 (AM-07). Additionally, the Division of Reclamation, Mining and Safety (DRMS) has approved 35 Technical Revisions (TR) to the Henderson Permit throughout its operational history since 1977. Historically, there has been little change in Henderson's primary operations since production was initiated. The Mine is located nine miles west of Empire, Colorado, in Clear Creek County on the eastern slope of the Continental Divide. Molybdenite ore is extracted and crushed underground and transported through a ten mile tunnel and five mile overland conveyor to the Mill for processing. The Mill site is located in Grand County on the west side of the Continental Divide, in the upper Williams Fork River Valley. Exhibit A includes the legal description of the Henderson Operation and Exhibit B contains the index map showing the location of the Henderson Mine and Mill. This document is being formally submitted to the DRMS as Amendment 08 (AM-08) to Reclamation Permit No. M-1977-342 to increase the affected land boundary for the Henderson Mill as described in Section 2.0 below. Once approved, this Amendment will become part of the existing permit. 2. AMENDMENT DESCRIPTION Henderson is proposing in this Amendment to expand the affected land boundary at the Mill below 1-Dam and 3-Dam to provide additional acreage to improve Henderson's water quality management program, monitoring network and related infrastructure, including access roads for new monitoring wells. 2.1 Affected Land Boundary Increase Area Below 1-Dam With this AM-08, Henderson is proposing an increase to the affected land boundary to the east/southeast and downgradient of the Tailing Storage Facility(TSF)to allow for the construction of roads to install and access additional water quality monitoring wells, and other infrastructure to expand the existing water quality management program already established in this area. The exact number and location of wells and access roads will be determined based on geophysical studies and as each new well is installed and more information becomes available. The proposed reconfiguration of the affected land boundary shifts the boundary eastward, along the property boundary. The net increase to the affected land area will be 82.5 acres (see maps in Exhibit Q. Area Below 3-Dam Henderson Operations AM-08 to Rec Permit M-1977-342 Climax Molybdenum April 2023 A Freeport-McMoRan Company Page 1