Sibanye-Stillwater holds various interests in a pipeline of exploration stage projects throughout the Americas – Rhyolite Ridge, Altar, Rio Grande and Marathon. We advance these exploration assets through strategic relationships with focused exploration companies.
A closer look
Rhyolite Ridge is an advanced stage exploration project located in Esmeralda County, Nevada, US. Rhyolite Ridge aims to extract a large, shallow lithium-boron deposit, located close to existing infrastructure, in between Las Vegas and Reno, Nevada. It is expected to be one of the first large-scale US lithium projects to enter production
The 50:50 JV agreement between Sibanye-Stillwater and ioneer Limited, whereby ioneer would maintain the operational management responsibility, is subject to the satisfaction of certain conditions precedent before Sibanye-Stillwater will commit funding to the project.
During 2022, ioneer submitted its Mine plan of operations (MPO) application for stage 1 mining, for review by the Bureau of Land Management (BLM). The BLM published a Notice of intent in the Federal Register during November 2022, which marked the commencement of work on the environmental impact statement (EIS) and public engagement process in accordance with the requirements of the National Environmental Policy Act (NEPA). The NEPA process culminates in the BLM’s Record of decision (ROD), a positive ROD will allow the company to commence construction of the Rhyolite Ridge Project. Ioneer’s best estimate is that an ROD would be received in Q1 2024. On completion of the NEPA process, once the MPO has been finalised, a NDEP-BMRR Reclamation Permit will be applied for, which would be the final major permit required.
In the meantime, study work in support of the MPO is ongoing, also aimed towards fulfilling some of the conditions precedent, which will enable the Group to make a final investment decision.
As at 31 December 2022, Rhyolite Ridge contained 10.2 million tonnes of declared attributable mineral resources at 0.16% lithium and 8.1% boric acid (H3bO3) (86.8 kilotonnes lithium carbonate equivalent (LCE) and 826.1 kilotonnes H3bO3).
The Altar exploration project is a shallow to intermediate depth copper-gold porphyry deposit located in San Juan province, Argentina, approximately 10km from the Argentine-Chile border and 180km west of the city of San Juan. Sibanye-Stillwater acquired the Altar project in 2017 as part of the Stillwater acquisition. Aldebaran Resources entered into a JV agreement with Sibanye-Stillwater in 2018 to acquire a 60%, and eventually 80%, interest in the Altar project, subject to funding certain exploration expenditures. Aldebaran Resources also assumed management of the JV. Sibanye-Stillwater currently holds a 40% stake in the Altar project after Aldebaran earned in 60% by August 2023.
As at 31 December 2022, Altar contained 1,408.6 million tonnes of declared attributable mineral resources at 0.4% copper and 0.1 g/t gold (13.1 billion pounds of copper and 4.3 million ounces of gold).
Latest news:
- 14 August 2023: Aldebaran announces it has earned a 60% interest in the Altar Project and is advancing towards earning an 80% Interest
For more information, see the Aldebaran Resources website:
The Rio Grande (north-west Argentina) exploration stage project (owned and managed by Aldebaran) is a copper-gold porphyry deposit with an associated iron oxide copper-gold (IOCG) style alteration. Sibanye-Stillwater holds a 17.59% interest in the project through its shareholding in Aldebaran Resources.
As at 31 December 2022, Rio Grande contained 19.7 million tonnes of declared attributable mineral resources at 0.3% copper and 0.3 g/t gold (119.1 million pounds of copper and 0.209 million ounces of gold).
The Marathon project is an advanced-stage PGM-gold-copper exploration project, at feasibility study level, located approximately 10km north of the town of Marathon, Ontario, Canada. The project is managed and operated by Generation Mining.
In Q1 2022, the former JV parties and Generation Mining Ltd. reached an agreement with the Group whereby Sibanye-Stillwater exchanged its project level ownership for a combined corporate level equity interest. As at 31 December 2022, Sibanye-Stillwater owned an effective attributable share of 18.19%, via its equity interest in Generation Mining. A March 2021 feasibility study, based on open-pit mining of the principle Marathon deposit, has indicated the project could have a robust rate of return at forecast palladium prices, and could produce an average of 245,000 ounces of palladium equivalent annually over a minimum 13-year mine life. Approximately 58% of the revenue will come from palladium, and a further 26% from copper, based on prices of US$1725/oz for palladium and US$3.20 for copper.
During 2022, Generation Mining continued the environmental approval process, while advancing detailed engineering on the project as well as arranging the production financing. The environmental assessment approvals from the Federal Minister of Environment and Climate Change, and the Ontario Minister of Environment were received on 30 November 2022.
As at 31 December 2022, Marathon contained 45.3 million tonnes of declared attributable mineral resources at 0.2% copper and 0.3 g/t 2E+Au PGMs (211.4 million pounds of copper and 1.0 million ounces of 2E+Au PGMs).


