Port Gregory in Western Australia is known for its significant deposits of heavy minerals. It is particularly well known for its quality alluvial garnet. Alluvial garnet is commonly used in industrial applications due to its hardness, specific gravity, and excellent abrasive properties. It is used for tasks like sandblasting, waterjet cutting, and polishing, because it can effectively remove material without causing excessive wear on the equipment, or generate excessive dust. Garnet is preferred in these applications, because it's relatively inert and environmentally friendly.

The mining and processing of garnet in this region are of economic importance and the region contributes to the global quality garnet market. And as the world focuses more and more on sustainability, it is expected that there will be a continued shift towards industrial garnet, away from inferior and environmentally unfriendly alternatives such as coal slag and silica.

Heavy Minerals Limited (HVY) is a mineral sands developer. They are developing the Port Gregory project, a garnet-rich deposit located in WA, for which IHC Mining played a crucial role in the initial test work and project design for this proposed mining operation.

First engagement and fully integrated study approach

IHC Mining first got involved with HVY in September 2021, when we were asked to undertake a maiden Mineral Resource estimate for their Port Gregory project. Such a resource assessment is done to determine and define the ore tonnage and grade of a geological deposit, in this case the one in Port Gregory. This assessment indicated that the Port Gregory region held a significant new resource of alluvial garnet and resulted in further work for IHC Mining.

Next step was to undertake preliminary pit optimisation and mine planning studies, which then led into a scoping study and metallurgical work. This was carried out at IHC Mining’s metallurgical test facility in Brisbane.

The image below shows the 3D geological block model which is derived from the client drill hole database and this forms the basis for the mining engineering work - which are both key building blocks of the Scoping Study.

Port Gregory Mineral Resource estimate — 3D geological block model: an oblique view of Port Gregory Mineral Resource Estimate

The scoping study was expanded to include project financial analysis and modelling to determine the best value outcome for HVY. This exercise provided a unique insight into the economics of the project, as well as being able to turn around mining, scheduling and processing options for the project in a timely manner. This resulted in an optimal outcome for HVY and the Port Gregory project.

Coarse garnet products under microscope

Fine garnet products under microscope

The Scoping Study based on the Port Gregory mining inventory had a $253M NPV, on a CAPEX of $110M. The study assumed a conventional dozer trap Dry Mining Unit (DMU) supported by truck and shovel feeding a 500 tph mining operation. A conventional wet concentrator circuit was then followed by a dry concentration circuit prior to screening for final saleable products.

HVY’s scoping study numbers were enough to secure Dutch government financial support for the potential development of the project (subject to due diligence) through a “funding letter of support” that was announced to the Australian Securities Exchange (ASX).

Next steps

HVY has engaged IHC Mining to carry out the next phase of studies which will be a Preliminary Feasibility Study (PFS). There will be another round of metallurgical testwork to support the PFS and IHC Mining will also conduct this work. These steps will flow through into a Definitive Feasibility Study (DFS) or potentially a Bankable Feasibility Study.

The Port Gregory project is planned to supply between 100 and 150,000 tonnes of garnet per year into the global garnet supply chain. The work that IHC Mining is doing to support this target, will ensure that HVY have the best chance possible to fulfill their objective of being the next major supplier of garnet to the world from the Port Gregory region.