London-listed Harena Rare Earths has completed its prefeasibility study (PFS) for the Ampasindava ionic clay rare earth project, in Madagascar.

The company, in a media release, says the PFS represents an important advancement in the development of the project, confirming its technical viability and providing a robust economic and operational framework to support the next phase of project progression.

The PFS was compiled by the company, with global engineering group SGS engaged to support technical inputs to the PFS and also to conduct an update of the 2023 mineral resource estimate to Joint Ore Reserve Committee (Jorc) 2012 standard.

Harena notes that the PFS indicates robust technical and economic viability for long-life heap leach operation.

The PFS indicates total rare earth oxide (TREO) of about 71 000 t, over a measured 20-year life-of-mine (LoM).

The plant throughput is set at five-million tonnes a year (dry) at an average grade of 1 500 ppm TREO supported by independent metallurgical testwork.

Harena notes a pre-production capital cost estimate of $142-million, including 25% in engineering, procurement and construction management and funding costs.

TREO production is estimated at 4 000 t/y.

This includes yearly oxide (neodymium/praseodymium and dysprosium/terbium) production of 1 700 t/y, equivalent to about 29 670 t for 20 years.

The company notes a ratio of magnetic rare earth oxide yielded to TREO despatched at 41%.

Moreover, Harena points out that the PFS indicates excellent economic returns modelled using analyst sourced long term pricing.

This includes an undiscounted LoM free cash flow of $1-billion post-tax; a pre-tax net present value (NPV) of $343.7-million; a pre-tax internal rate of return (IRR) of 34%; a post-tax NPV of $249.6-million; a post-tax IRR of 30%; and a payback period of four years.

Harena notes that outstanding financial metrics are based on current publicly sourced consensus rare earth pricing.

This includes an undiscounted LoM free cash flow of $2.6-billion post-tax, a pre-tax NPV of $616.1-million; a pre-tax IRR of 30% (with consensus pricing more optimistic in later years); a post-tax NPV of $464.3-million; a post-tax IRR of 27%; and a payback period of five years.

The company says it has modelled the Ampasindava project’s economics using two sets of rare earth oxide price forecasts.

The base case uses a price deck sourced from a recognised Minerals Analyst for 2025 to 2044.

The consensus price deck is sourced using AI applications that scrape web information on publicly available REO pricing forecasts between 2030 and 2049.

In addition, the company has modelled a situation, called Ampas Plus, using the base case price deck with a 10% reduction in operational and capital expenditure applied throughout.

Meanwhile, Harena also notes that the Ampasindava project is rapidly advancing and progressively de-risked.

The company explains that planning for a phased “proof of concept” plant at site is under way, with the initial establishment of a permanent on-site laboratory; the establishment of on-site test cribs and columns; and an opportunity to optimise flowsheet and test downstream rare earth separation at a pilot scale.

Additionally, Harena notes that there are a selection of specialists to compile the definitive feasibility study (DFS) and upgraded PFS to reduce cost and process risk.

The company says it has commenced targeted cost reduction and optimisation initiatives, which includes the selection of high-grade zones for initial inclusion in mine plan and the optimising of supply chain options.

The company also notes that it has strong national government support, noting that it has embarked on strong engagement with Malagasy national and regional governments.

In this regard, Harena notes that environmental and social studies continue to support permitting and local validation, adding that permitting is on track to allow construction to begin in 2027.

Harena says social programmes will focus on suitable and appropriate land compensation, job creation, youth education, individual technical skills development and local business creation and readiness.

“The completion of the PFS represents a significant step forward for Harena and the Ampasindava project.

“With significant previous investment in resource development, process testwork and environmental programmes, we have an excellent understanding of the Ampasindava project where we can now further optimise the asset as we move into the final piloting and studies phase,” says Harena executive technical director Allan Mulligan.

He notes that the Ampasindava project hosts a “world-class” scale ionic absorption rare earths mineralisation, particularly amenable to low cost and high yield recoveries.

He says the sustainable and rapid remediation heap leach extraction model will serve to enhance the local, regional and national economy with no lasting impacts on the environment.

“Our confidence in the results of the PFS and the underlying PFS process more broadly is based on the enormous previous works and current understanding of the orebody, and the inclusion of the proof-of-concept plant in 2026 will allow a smooth and organised mobilisation into construction with reduced start up risk.”

“We are extremely pleased to be releasing the excellent results of this pre-feasibility study to the market.

“The key metrics presented here clearly highlight the exceptional scale, quality and strategic significance of the Ampasindava project, reinforcing its position as a world-class heavy rare earth asset and marking a major milestone in its progression towards development.

“I would like to sincerely thank Allan Mulligan, our executive technical director, for his dedication over the recent months, as well as the wider internal and external teams whose expertise and commitment have been instrumental in delivering this important result,” adds Harena executive chairperson Ivan Murphy.