Key Highlights

  • An engineering and processing assessment confirms front-end capacity of about 216,000 tonnes per year.
  • The figure reflects two parallel grinding circuits, each rated at roughly 108,000 tonnes per year.
  • The plant was previously operated by Agnico Eagle at Hope Bay.
  • Downstream refining is identified as the key constraint on antimony output.

Nova Minerals (ASX:NVA) says an engineering and processing assessment has confirmed that the front end of its Port MacKenzie processing Facility in Alaska can handle about 216,000 tonnes per year. The figure reflects two parallel grinding circuits, each rated at roughly 108,000 tonnes per year, and forms part of the company's plan to build an Alaskan hub for antimony and other critical minerals.

The plant was previously operated by Agnico Eagle at Hope Bay and includes crushing, grinding, gravity, flotation and leaching circuits. Nova has separately acquired a Steinert ore sorter. Chief executive Christopher Gerteisen called the capacity confirmation "a significant milestone" for the company.

From a pilot refinery to larger scenarios

The first stage is an initial project that the company describes as fully funded at US$43.4 million and supported by the US Department of War. It involves a pilot refinery able to produce up to about 600 tonnes per year of refined antimony. Nova is targeting military-grade antimony trisulphide and antimony metal of better than 99.65 per cent purity, with first production targeted for 2027.

Beyond the pilot stage, the company's modelling suggests the front-end capacity could support around 9,400 tonnes per year of refined antimony if feed averaged 5 per cent antimony, and up to 20,000 tonnes per year at a 10 per cent feed grade. Nova said the main requirement for reaching those levels would be additional Downstream refining capacity rather than changes to the grinding and concentrating stages.

Grinding, gravity and flotation circuits upgrade ore into a concentrate, but turning concentrate into antimony trisulphide or high-purity metal requires a separate refining step. A plant can therefore have ample milling capacity while its output of finished product is limited by the size of the refinery attached to it.

Why antimony processing matters

Antimony is used in flame retardants, batteries and defence applications, including munitions, and governments have increasingly treated it as a strategic material because Supply chains have been concentrated outside the United States. A domestic facility capable of turning concentrate into refined products addresses a step in the chain that Mining alone does not, which helps explain the defence-related support for the pilot project.

Nova also said it is evaluating toll processing of other materials, including tungsten, gallium, bismuth, tellurium and arsenic. The update also referred to the company's Estelle Project.

Limitations and risks

The larger output numbers are modelling scenarios rather than production forecasts. They depend on securing enough feed at the assumed grades, whether from Nova's own projects or third parties, and on funding and building the extra refining capacity, which has not been described as funded. A 5 or 10 per cent antimony feed grade is an assumption for modelling purposes, not a reported resource grade.

The 216,000 tonne figure relates to front-end throughput only. Refining is the stated bottleneck, and the pilot refinery's planned capacity of about 600 tonnes per year is a small fraction of the modelled scenarios.

What comes next

The near-term milestone is the funded pilot refinery and first production targeted in 2027. Further growth would require decisions on downstream refining expansion and on securing sufficient antimony feed, along with progress on the toll processing evaluation. Nova is listed on both the ASX and NYSE American, and the progress of refinery construction and feed supply arrangements will be the practical test of the hub concept.