Overview

Deposit type

• Sediment-hosted

Summary:

The project area is located approximately 65 miles northwest of Ely, Nevada, in an area of uplifted Paleozoic through Tertiary rocks. The area is part of a corridor of northwest-southeast directed Tertiary extension in the Basin and Range province of Nevada. The study area is characterized by two north-trending uplifted blocks, the Bald Mountain-Buck Mountain Ridge on the west and Alligator Ridge on the east, separated by a fault valley that encompasses Mooney Basin, the Alligator Ridge deposits, and the Yankee and Vantage deposits.

The Bald Mountain Mining District falls along the southeastern extension of the Carlin trend (Nutt et al.2000). The district contains two separate but adjacent mineral trends: 1) the northwest-southeast Bida trend that parallels the Carlin trend; and 2) the Yankee-Alligator Ridge-Mooney Basin trend that follows the north-northeast trend of the structural basin between the Bald Mountain-Buck Mountain Ridge and Alligator Ridge. The geology of the district is quite complex and consists of a variety of reactivated folds and faults that serve to localize the gold deposits.

The Bida trend is a northwest-southeast structural trend that encompasses the Bald Mountain stock and gold deposits associated with the intrusion of this Jurassic quartz monzonite stock (Nutt et al. 2000). The gold deposits are disseminated along high-angle structures in the Jurassic stock and in the adjacent Cambrian and Ordovician sedimentary rocks. Gold is associated with pyrite, arsenopyrite, marcasite, and argillic alteration. Mineralized limestones have garnet-epidote skarns with associated tungsten, molybdenum, and zinc (Nutt et al. 2000). The deposits were formed at a depth of 3 to 6 km from magmatic fluids associated with the intrusion of the Bald Mountain stock during the Jurassic. The RBM deposit is a higher level deposit in Mississippian clastic sedimentary rocks. Productive ore zones are found at the contact between the Eldorado Limestone-Geddes Limestone and the Secret Canyon Shale, along the contact between the Hamburg Limestone and the Dunderberg Shale, and in the upper part of the Pogonip Group. Uplift of the Bald Mountain area during the Tertiary exposed these gold deposits to erosion and set the stage for discovery and development of gold resources within the Bald Mountain Mining District.

The Mooney Basin-Alligator Ridge-Yankee trend consists of gold deposits that are typical of Carlin-type gold deposits and consist of disseminated gold associated with jasperoid, decalcification, sericite, and clay alteration. Gold is found with pyrite, sphalerite, arsenopyrite, marcasite, realgar, orpiment, stibnite, and barite. The deposits are often associated with reactivated Mesozoic faults and fractures, are localized along the edges of folds, and are stratabound in the Pilot Shale in a zone 100 to 200 feet in thickness (Nutt et al. 2000). Most deposits are associated with jasperoid in the underlying Guilmette Formation. These deposits are Eocene-Oligocene (Tertiary) in age and formed in a shallow, epithermal hot spring environment (Nutt et al. 2000) along a Basin and Range structural basin. Thus, these deposits are considerably younger than the gold deposits with the BMM area.

Mining Methods

• Truck & Shovel / Loader

Summary:

The Bald Mountain operation is an open pit mining operation with production from a number of different pits. The two main deposits (Saga and LBM) represent approximately 76% of the known reserves. Bald Mountain includes several other deposits scattered over the property, and three ROM heap leach pads (Bald Mountain, Mooney and Vantage).

Bald Mountain mine is mined using standard open pit methods including drilling, blasting and loading into haul trucks. Typical bench heights are 25 to 40 feet high and of variable width. Overall pit wall slope angles range from 30 to 55 degrees. Blasted ore and waste rock are loaded into haul trucks by front-end loaders or electric and hydraulic shovels. Ore is hauled to the run-of-mine (ROM) leach pad.

Comminution

Crushers and Mills

Processing

• ROM/dump leach
• Carbon in column (CIC)
• Carbon adsorption
• Cyanide (reagent)

Summary:

Bald Mountain recovers gold using multiple ROM heap leach pads. Gold is extracted from the ore with a cyanide solution and collected on activated carbon in CIC plants. Loaded carbon is shipped off-site for further processing and ultimate gold refining.

The heap leach operations are divided into three areas: Bald, Mooney (North, South and Deep South), and Vantage. Vantage is the newest of the areas and became operational during the recertification period. The carbon-in-column (CIC) processing plants include: Process Plant 2, Mooney North Plant, Mooney South Plant, and the Vantage Plant. The Vantage Plant utilizes an innovative vertical CIC process. All operations noted here are within the North Operations Area (NOA) except for the Vantage Complex which is in the South Operations Area (SOA).

The Bald Mountain Mine Area includes:
• Process Area #1 which is no longer in operation. This consisted of a leach pad, five process ponds and a process building. The facilities have been decommissioned and the ponds backfilled. The area is currently under reclamation.
• Process Area #2 includes leach pads (Bald Leach Pad (previously pads 2 through 4) and Leach Pad 5), Pregnant Sump (PS1), Overflow Pond (POF1) and Secondary Pond (P4), two pregnant solution ponds (P5 and P6), Barren Pond (P7), Carbon-in-Column (CIC) process plant and cyanide offloading facility. However, the leach pads are not being actively leached; cyanide has not been added to the leach pads in over 12 months. The leach pads continue to drain down and the CIC process is still operational.

The Mooney Basin Area includes three process areas:
• North Area Facility, comprising a leach pad (Original Pad and Expansion Pads I, II, and III), two process solution ponds, a storm/event pond, Carbon-in-Column (CIC) process plant and cyanide off-loading facility;
• South Area Facility, comprising Leach Pad 4, a process solution pond, a storm/event pond, a solution collection tank, CIC plant and cyanide off-loading facility.
• Deep South Area Facility, comprising Leach Pads 5 and 6, a process solution pond, one storm/event pond, and a solution collection tank. Pregnant solution from this facility is piped to the South Area CIC plant for processing.

Originally, the Mooney North and Mooney South Area facilities operated independently. Pregnant and barren solution lines were constructed that connected these facilities, allowing solution to be pumped between them as needed.

The construction of the Vantage Complex began in Quarter 1 2018. The Vantage Complex is in the South Operations Area, was commissioned in 2019, and consists of:
• A leach pad, a solution collection tank, a process solution pond, a storm/event pond, CIC process plant, two cyanide storage tanks, and a cyanide off-loading area.

Water Supply

Summary:

The Company re-uses recycled process water to the greatest extent possible. Every site measures how much water is used to project future water use over the life of mine.

In 2022, three out of the six operating mines (50%) were located in regions characterized by water stress, Tasiast in Mauritania, La Coipa in Chile and Bald Mountain in Nevada, USA. In keeping with the company-wide water balance accounting methodology, Kinross includes precipitation captured in our water withdrawn calculations. While precipitation is captured at all three sites, only the Bald Mountain (one out of three sites) withdraws and consumes fresh water from source (groundwater).

Bald Mountain, located in Nevada, U.S.A., is within an area categorized as arid and low water use Kinross’ criteria for assessing water risk supports this classification. Bald Mountain is a heap leach operation and maintains a high water recycle rate, achieving a rate of 93% in 2023.

Production

Operational metrics

Personnel

Job Title	Name	Profile	Ref. Date
Chief Metallurgist	Rodrigo Andrade		Jun 10, 2024
Health, Safety & Training Manager	Deanna Hall		Jun 10, 2024
Maintenance Planner	Jonathan Jordan		Jun 10, 2024
Process Maintenance Superintendent	Mark Wilson		Jun 10, 2024
VP and General Manager	Joseph Kemp		Jun 10, 2024