Trial mining operations at rare earths producer Rainbow Rare Earths’ Gakara operation, in Burundi, continue to strengthen, with concentrate production having increased to an average of 59.9 t a month from June to September.

This is an increase from the 31.7 t a month average achieved between October 2019 and May.

Further increases in the trial mining fleet are planned to allow growth in trial mining production to 100 t a month concentrate, thereby better utilising capacity of the existing pilot processing plant, the miner said in a statement on October 7.

With this new trial mining capacity, Rainbow intends to extend the areas of trial mining, initially to the Gasenyi area to the north of the Murambi site, generating an improved detailed geological knowledge across a wider area of the mining licence.

This is expected to allow 100 t a month of high-grade rare earths concentrate to be produced from the current pilot plant.

Concentrate shipments are also expected to grow, with 100 t of concentrate shipped on October 5, and a further 210 t of concentrate, which was in stock at September 30, being prepared for shipment.

The growing volumes are being delivered into an improving rare earths pricing environment, with neodymium/praseodymium oxide prices strengthening 30% to $48 050/t at the end of September; up from $36 850/t in April.

CEO George Bennett said the ongoing strengthening of the trial mining and processing operations at Gakara were "an important element of Rainbow’s long-term strategy to develop a large-scale commercial mine”.

The expanded trial mining fleet will enable the miner to open up new areas, thereby increasing its understanding of the mineralisation in parallel with Rainbow’s planned exploration activities.

“We continue to demonstrate the amenability of ore sourced from across the mining licence area to a simple gravity process to deliver a high-grade concentrate with low levels of radioactive elements, suitable for export,” Bennett explained.

He added that no reagents were used to produce Rainbow's concentrate, which delivered both a low environmental impact and a low processing cost, compared with more complex rare earth processing requirements.

Using the full capacity of the existing pilot plant will generate additional revenue to offset the costs of ongoing exploration and evaluation activities ahead of full-scale commercial development.

In October, Rainbow intends to further increase the mining fleet to increase the capacity of the trial mining operations, allowing the full 5 t/hr capacity of the current pilot processing plant to be realised.

A new 34 t excavator has been ordered to supplement the existing 20 t excavator used for waste and smaller backhoe loader excavators used for selective mechanical mining of ore.

Two further trucks will also be sourced to fully use the new excavator capacity once financing is available.