Made in America: Locksley Resources’ Path to Securing the US Antimony Supply Chain

The United States is increasingly reliant on foreign sources for critical minerals, a situation that poses significant risks to national security and economic stability. Antimony, a metalloid with unique properties, is one such mineral. It plays a vital role in defense, energy, and various industrial applications. Currently, the U.S. imports most of its antimony, primarily from China, creating a strategic vulnerability. According to the U.S. Geological Survey, China was the source of 63% of U.S. antimony imports through 2023. This dependence has spurred efforts to re-establish a domestic antimony supply chain, and Locksley Resources is emerging as a key player in this endeavor.

The Critical Importance of Antimony

Antimony (Sb), a silvery-gray metalloid, is not abundant in the earth’s crust, with an estimated presence of about 0.2 parts per million. Despite its scarcity, antimony is indispensable in numerous industries due to its unique properties, such as its ability to harden and strengthen certain metals. It has been recognized as a critical mineral by countries including the United States, China, Australia, and Russia.

Key Applications of Antimony

Defense and Military: Antimony is a key component in flame-retardant materials, armor-piercing ammunition, and explosives. The U.S. Department of Defense relies heavily on antimony for its military applications.
Flame Retardants: A major portion of global antimony consumption is for flame-retardant materials used in plastics, textiles, and electronics. Antimony trioxide is a prominent additive for halogen-containing flame retardants.
Batteries: Antimony is a critical ingredient in lead-acid batteries, enhancing their longevity and performance. It is also being explored in emerging battery technologies like liquid metal batteries (LMBs).
Semiconductors: Used in the production of diodes and infrared detectors. Antimony is used as a dopant in semiconductor devices.
Alloying Agent: Added to lead and tin alloys to increase hardness and durability, which is crucial for bearings, ammunition, and solders.

The U.S. Antimony Supply Chain Vulnerability

The United States has been increasingly reliant on imports to meet its antimony needs. China has been the world’s leading producer of antimony, accounting for a significant portion of the global supply. This reliance on foreign sources, particularly China, poses a significant risk to U.S. national security and economic stability.

Factors Contributing to the Vulnerability

Lack of Domestic Production: The U.S. has not mined antimony since the closure of the Sunshine Mine in Idaho in 2001.
Geopolitical Tensions: Growing tensions with China and Russia, the leading antimony producers, have raised concerns about supply disruptions.
Export Restrictions: China has imposed export restrictions on antimony, raising serious concerns for countries like the United States, which rely heavily on Chinese supply.

Locksley Resources: A Path to Domestic Antimony Security

Locksley Resources Limited (ASX: LKY) is an Australian-based explorer focused on critical minerals in the United States. The company is actively advancing its U.S. asset, the Mojave Project, in California, targeting rare earth elements (REEs) and antimony. Locksley’s Mojave Project, located in California, represents one of the highest-grade known antimony occurrences in the U.S.

Key Highlights of Locksley’s Mojave Project

High-Grade Antimony Prospect: The Desert Antimony Mine (DAM) prospect features samples with high antimony content.
Metallurgical Breakthrough: Locksley has achieved excellent metallurgical test results at its Mojave Project, demonstrating a clear pathway to establishing America’s first domestic antimony supply chain in decades. With recovery rates reaching 85.9% and concentrate grades up to 59.6% antimony, these results validate the project’s potential to deliver high-quality feedstock for critical mineral production.
Strategic Alliances: Locksley has engaged Washington DC-based advisory group GreenMet to help position its Mojave antimony and rare earth project within US strategic frameworks such as the Defense Production Act, Inflation Reduction Act, and Department of Energy initiatives. Locksley has also formed a research alliance with Rice University to pioneer US-based processing technology for antimony as well as explore its applications in energy storage.
“Made in America” Focus: Locksley is driving towards a “100% made in America product” with the goal to position Locksley as the US beachhead for mining, sourcing, and processing of antimony.

Recent Developments

In September 2025, Locksley Resources received initial metallurgical testwork results validating that the Mojave Project in the US can deliver the feedstock required to underpin a domestic mine-to-market antimony supply chain.
Locksley is working with Rice University to develop DeepSolv™, for domestic processing of North American antimony.

Challenges and Opportunities

While Locksley Resources’ Mojave Project holds significant promise, there are challenges to overcome in establishing a robust domestic antimony supply chain.

Challenges

Environmental Regulations: Antimony mining can be environmentally risky, and stringent regulations must be followed.
Permitting: Restarting mining operations involves overcoming regulatory and environmental challenges.
Competition: Other companies are also working to develop domestic antimony sources.

Opportunities

Government Support: The U.S. government is increasingly focused on securing domestic supply chains for critical minerals and is providing support for projects like Locksley’s Mojave Project.
Technological Advancements: New processing technologies, such as DeepSolv™, can improve the efficiency and sustainability of antimony production.
Growing Demand: The demand for antimony is expected to grow in the coming years, driven by the increasing use of flame retardants, batteries, and semiconductors.

The Path Forward

Securing a domestic antimony supply chain is crucial for U.S. national security and economic stability. Locksley Resources is playing a key role in this effort, and its Mojave Project has the potential to become a cornerstone of American antimony supply security.

Key Steps to Strengthen the U.S. Antimony Supply Chain

Continued Exploration and Development: Further exploration and development of domestic antimony resources are needed.
Investment in Processing Technologies: Investment in new processing technologies can improve the efficiency and sustainability of antimony production.
Government Support: Continued government support for domestic antimony projects is essential.
Diversification of Supply: While domestic production is the ultimate goal, diversifying import sources in the short term can reduce reliance on China.

By taking these steps, the United States can reduce its dependence on foreign sources of antimony and secure its supply chain for this critical mineral. The success of companies like Locksley Resources will be vital in achieving this goal. What measures should the U.S. government take to incentivize domestic antimony production, and how can international collaborations with friendly nations contribute to a more resilient and diversified antimony supply chain?