American Tungsten & Antimony Ltd (ASX: AT4), a critical minerals company focused on establishing secure domestic supply chains for antimony and tungsten through integrated US-based operations, has announced a binding framework agreement with Mammoth Minerals Limited (ASX: M79). This strategic pact combines exclusive future tungsten offtake rights, a significant equity investment, and a joint work programme designed to vertically integrate Mammoth’s Kilba Tungsten Project in Western Australia with AT4’s Del Sol Refinery in Nevada, USA. The agreement represents a crucial step in AT4’s strategy to secure feedstock for its planned ammonium paratungstate (APT) production.
Under the terms, AT4 gains the exclusive right to purchase 20% of all tungsten concentrate produced from the current Kilba Mineral Resource, which is reported by Mammoth with a JORC 2012 Mineral Resource of 7.2 million tonnes at 0.19% WO₃. This concentrate is destined for processing into APT at AT4’s Del Sol Refinery. Additionally, AT4 will make a strategic investment of approximately A$1.577 million by subscribing for 60,666,666 ordinary shares in Mammoth, representing about 8.6% of the company. These funds will be primarily allocated to Mammoth’s acquisition and evaluation of Kilba.
This mine-to-APT pathway is specifically designed to cater to US defence customers, ensuring a supply chain free from “covered-country” involvement from mine to APT, thereby meeting US defence sourcing restrictions effective from 1 January 2027. A joint work programme is now underway, covering bulk sampling, beneficiation, hydrometallurgical testwork, and logistics, overseen by a committee chaired by AT4. Kilba marks the first external feedstock partnership under AT4’s multi-source Del Sol feed strategy, which also encompasses its own Tennessee Mountain and Dutch Mountain projects, further solidifying the company’s vertically integrated supply chain ambitions.
AT4 CEO, Casper Adson, commented that this is a company-defining strategic step, securing an exclusive position over future tungsten output and aligning with an allied-country owner. He highlighted that this model, leveraging the Del Sol industrial platform and the Mineral Intelligence Engine™, stands apart in the US tungsten market and strengthens the case for US and Australian government non-dilutionary funding for an allied-nation mine-to-APT supply chain.
