Name of the Mine
Round Mountain mine.

Location
Round Mountain is located in the Big Smoky Valley, in Nye County, central Nevada, US. 

Mine Owner/s
The mine is wholly owned by Kinross Gold Corporation and is owned and operated by Kinross’s wholly owned subsidiary Round Mountain Gold Corporation. 

Brief Description
Kinross controls mineral and surface rights covering about 17 336 ha through ownership or lease of patented and unpatented mining claims. The broader operation includes two openpits: Round Mountain and Gold Hill, where mining was completed in December 2023. 

Brief History
Round Mountain is an operating mine.

First gold production from the Round Mountain district occurred in 1906. The original Smoky Valley Common Operation was formed in 1975 to operate the mine, and commercial production started in 1977. The site has produced about 17-million ounces of gold since inception.

Kinross acquired its first 50% interest in 2003 and became the 100% owner in 2016. 

Construction and commissioning of the mine’s Phase W project were completed in 2019. First gold was poured from the vertical carbon-in-column plant in May 2019. Mining of Phase W was completed in mid-2025.

The optimised Phase S openpit expansion was approved in the fourth quarter of 2023. Mining of Phase S started in January 2024 and is expected to be completed by mid-2028. 

Kinross started construction of an underground exploration decline at Phase X in the first half of 2023, completed the first phase of construction and exploration development in 2024, and executed a second phase during 2025. 

Kinross announced in January 2026 that it would be progressing with the development of the Phase X project – a bulk tonnage underground mining operation below the current Phase W openpit at Round Mountain. This project targets higher-grade, lower-cost mining of the same mineralisation at depth as part of the company’s grade optimisation strategy to offset inflation and increase future margins at the site. 

Primary Metals/Minerals
Gold

Secondary Metals/Minerals
Silver is reported only in relation to Gold Hill. 

Geology/Mineralisation
The Round Mountain gold deposit is a very large, epithermal, low-sulphidation, volcanic-hosted, hot springs-type, precious metal deposit.

The deposit is underlain by highly deformed sedimentary rocks of Cambrian through Permian age that have been intruded and locally metamorphosed by several granitic plutons of Cretaceous age. These rocks are, in turn, overlain by a sequence of Oligocene to Miocene age rhyolitic ash-flow tuffs that were erupted from several exposed and buried caldera sources. 

Paleozoic sedimentary rocks occur as a series of stacked thrust sheets. A minimum of three thrust sheets, placing Cambrian and Ordovician rocks over Permian rocks, have been recognised. 

The Paleozoic sediments are intruded by several granitic plutons of Cretaceous age. The basement rocks are overlain by Oligocene to early Miocene aged rhyolitic ash-flow tuffs that originated from several eruptive centres in the Toquima and Toiyabe ranges. 

The Round Mountain Caldera (RMC) is one of the most prominent geologic features of the southern Toquima range. 

The geology of the Round Mountain mine comprises a thick sequence of intracaldera Oligocene ash-flow tuffs and volcaniclastic rocks resting on pre-Tertiary basement rocks. The caldera margin is buried, but in the pit area is well defined by a progressively steeper dipping arcuate contact between the volcanic rocks and older basement rocks. The caldera margin and caldera-related structures provided the structural ground preparation for the hydrothermal system that introduced gold mineralisation. The primary host rocks for gold mineralisation are the volcanic rocks. A minor amount of ore occurs in the Paleozoic rocks along the caldera margin.

Gold mineralisation within the Round Mountain deposit occurs as electrum in association with quartz, adularia, pyrite and iron oxides. Shear zone fractures, veins and disseminations within the more permeable units host the mineralisation. Primary sulphide mineralisation comprises electrum associated with or internal to pyrite grains. In oxidised zones, gold occurs as electrum associated with iron oxides, or as disseminations along fractures.

Reserves
Round Mountain had proven and probable gold mineral reserves as at December 31, 2025,  of about 45.06-million tonnes grading 1.3 g/t gold. No silver reserves are reported for Round Mountainfor Round Mountain.

Resources
Round Mountain had total indicated gold mineral resources, exclusive of mineral reserves, of 81.28-million tonnes grading 0.6 g/t gold as at December 31, 2025. No measured gold mineral resources were reported. Inferred gold mineral resources were 61.269-million tonnes grading 1 g/t gold.

Inferred silver mineral resources were reported at 36.648-million tonnes grading 6.9 g/t silver for 8.117-million ounces, with all silver resources attributable to Gold Hill. 

Type of Mine
The current operation is an openpit mine, with an underground transition under way through the Phase X project.

Mining Method
Round Mountain and Gold Hill use conventional openpit mining methods. 

Phase X is planned as a bulk-tonnage underground mining operation below the current Phase W openpit. Kinross’ Phase X mine plan includes three underground accesses, comprising two declines already in place and a third decline planned for 2028 to enhance ventilation and haulage routes. 

Phase X ore will be processed through the existing mill in parallel with remaining openpit mineralisation and stockpiles.

Major Infrastructure/Equipment
Existing infrastructure includes crushed-ore and run-of-mine heap-leach facilities, a mill with gravity/flotation circuits, dedicated heap-leach pads, a vertical carbon-in-column plant, truck shop, wash bay, warehouse and fuelling facilities. Phase X is expected to use the existing 10 000 t/d milling facility at Round Mountain, blending higher-grade underground mineralisation with lower-grade openpit production from Phase S and, thereafter, low-grade stockpiles from historic openpit mining.

For Phase X, forecast initial capital costs of about $400-million comprise underground development and mining equipment, underground infrastructure, and indirect and contingency costs. 

Prospects
Phase X expansion is expected to incrementally produce about 1.4-million gold-equivalent ounces over an initial 11-year mine life, starting in 2028, and to extend production at Round Mountain to 2038. 

Exploration will focus on proximal and down-dip extensions of the Phase X resource, further infill drilling of the lower zone and surface exploration targeting future openpit extensions on the broader Round Mountain land package. 
Kinross also continues to advance initiatives to optimise the operation and potentially extend the openpit mine life.

Contact Details
Kinross Gold Corporation
Tel +1 416 365 5123 
Email info@kinross.com
Website https://www.kinross.com/