Nova Minerals Ltd (ASX:NVA, OTCQB:NVAAF) has identified several material opportunities to improve the economic context of the Estelle Gold Project in Alaska after a strategic review of the project, including heap leach processing, optimised ore sorting and critical minerals extraction.
The company says improvements from the review could increase gold production while reducing capital and operating costs – the proposed modifications are now being tested by METS Engineering (METS) and Rough Stock Mining (Rough Stock) as part of pre-feasibility level studies.
Supplying gold and critical minerals
“The strategic review has been a major success and put us on a clear path to production,” Nova Minerals CEO Christopher Gerteisen said.
“We will now look to grow on the success achieved by completing these critical path studies, exploration upside and advancing the project through 2024 and beyond.
“Estelle is a major mineralised trend with abundant gold and critical minerals and we are on track towards development with the support and assistance from our partners in government and academia.
“We see decades of potential once production commences. Our mission is to grow and secure US domestic supply of gold and critical minerals.
“We will keep our shareholders updated on progress including the results of material studies as we move forward.”
Optimisation goals
The improvements being tested by METS and Rough Stock include:
- Optimised plant size to process high-grade ore early in the mine schedule, with a smaller milling circuit, and more selecting ore sorting to commence in 2 to 3 years to process the medium grade material, with lower grade material sent to heap leach;
- Evaluation of heap leaching potential, a well-proven low-cost gold recovery method for lower grade material and material rejected from ore sorters to lift annual gold production;
- Investigating various heap leaching options, including agglomeration and alternative leach reagents;
- Assessing extraction options of the highly elevated concentrations of silver, copper, antimony and other critical minerals identified across the project which could potentially provide valuable by-product credits;
- Reviewing various selective ore sorting options on material from both RPM and Korbel with Steinart ore sorting to test a combination of different sensors including, XRT density, colour, laser and induction, to potentially improve the ore sorting results further;
- Increasing mine slope angles to greater than 50 degrees from the 45 degrees used in the scoping study;
- Investigating alternative technology options, such as SAG (Semi Autogenous Grinding) mills, coarse flotation using Hydrofloat technology and gravity recovery using a Reflux Classifier to further improve and optimise the process flowsheet;
The review also made several suggestions around the project’s trajectory and milestones, including:
- Need for more drilling at the RPM deposit, with a focus on improving the confidence categories of the mineral resource to produce a larger ore reserve for a pre-feasibility study (PFS);
- Maiden drilling at several prospects to follow up gold, antimony and several other critical mineral surface samples;
- Review Stibium prospect as a potential source of early cash flow with potential for antimony or critical mineral concentrate production;
- Demonstrate ore sorting capabilities on a larger scale, with plans for up to 200,000 tonnes for the pilot scale ore test program;
- Review of access roads for early stages of mine production and construction;
- Review of power options to meet start-up requirements for Estelle with potential to scale up in the future.