Name of the Project
Monte Muambe rare earths and fluorspar project.

Location
North-western Mozambique.

Project Owner/s
Altona Rare Earths (51%).

Project Description
A scoping study has proposed the openpit mining of Target 1 and Target 4 at the Monte Muambe project over a life-of-mine of 18 years.

An estimated 750 000 t/y of ore is planned to be extracted and processed through a beneficiation plant to produce a rare-earth concentrate.

The beneficiation process will include crushing, milling and flotation.

The concentrate will be processed through a hydrometallurgical plant to produce an average of 15 000 t/y of mixed rare-earth carbonate.

The hydrometallurgical process will involve a weak acid gangue leach, followed by rare earths leaching and purification.

The mixed rare-earth concentrate product will be packaged and transported by existing road infrastructure to the Port of Beira, in Mozambique, for export.

Potential Job Creation
Not stated.

Net Present Value/Internal Rate of Return
The project has an after-tax net present value, at an 8% discount rate, of $283.3-million and an internal rate of return of 25%, with a payback of 2.5 years.

Capital Expenditure
Initial capital expenditure is estimated at $276.3-million.

Planned Start/End Date
Not stated.

Latest Developments
The initial flotation rougher test results, Test F5, have shown a high rare earths recovery of 69.3% and good selectivity of rare-earth minerals, compared with fluorite.

A review of the project's potential for fluorspar production has started, including the possible short-term production of metallurgical-grade fluorspar from low-tonnage high-grade hydrothermal fluorspar veins.

These fluorspar veins have legacy drilling intercepts of up to 10 m at 54.77% calcium fluoride (CaF₂) and trenching intercepts of up to 16 m at 71% CaF₂.

Mineralogy and partial flotation rougher test results have been received from metallurgical testing and analytical services provider SGS Lakefields.

Froth flotation is a standard separation method for minerals from milled ore, and rougher flotation is the first stage of concentration.

The mineralogical testing has confirmed that rare earths are mostly contained in rare earths’ fluorocarbonates – bastnaesite, parasite and synchisite –  which are 71% by weight, monazite 18% and other rare earths minerals 11%.

A range of flotation parameters and reagents have been tested, with Test F5 showing the best results.

The company has said the results obtained so far provide a clear pathway for further optimisation of flotation parameters, which will take place over the coming weeks.

Monte Muambe was originally known for its fluorspar potential, and legacy mineral exploration activities were largely focused on this mineral.

Considering the currently depressed prices of rare earths, the company considers the reassessment of the economic potential of associated minerals as a “prudent course of action.”

At Monte Muambe, fluorspar is encountered as disseminations in rare-earth ore, and as hydrothermal veins lining the contact between carbonatites and fenites.

Assays of drilling samples obtained by Altona since 2021 have shown the ubiquitous presence of disseminated fluorspar in rare earths ore at Target 1 and Target 4, with a grade averaging 13.2% CaF₂ for samples having more than1.5% total rare-earth oxide, and reaching as high as 70.45% CaF₂.

The representative rare earths ore sample sent to SGS Lakefields for metallurgical testing contains 16.8% CaF₂.

The objective of ongoing metallurgical testwork at SGS Lakefields is also to assess the possible separation of a fluorspar concentrate by-product.

Legacy exploration work in the western part of the Monte Muambe carbonatite intrusion resulted in the definition of a historical Joint Ore Reserve Committee-compliant inferred mineral resource of 1.6-million tonnes at 19% CaF₂.

This estimate covers disseminated and hydrothermal fluorite. A review of legacy drilling and trenching data shows that hydrothermal fluorite veins have a thickness ranging from 10 m to 20 m, with grades of up to more than 70% CaF₂.

The company will review legacy data, collect new samples and data on site in October, and prepare a conceptual study to assess the possible short-term production of metallurgical-grade fluorspar from known high-grade hydrothermal fluorspar veins of the fluorite zone.

Key Contracts, Suppliers and Consultants
None stated.

Contact Details for Project Information
Altona Rare Earths business development, Christian Taylor-Wilkinson, tel +44 7795 168 157 or email ctw@altonaRE.com.