Rainbow Rare Earths
Bastanesite mineralised sample.

LSE-listed rare earths element (REE) mining company Rainbow Rare Earths has started work on its Gakara rare earths project in Burundi.The project which is expected to produce first rare earth oxide (REO) concentrate in the fourth quarter of this year – just nine months after work at the project began Rainbow Rare Earths CEO Martin Eales tells Chantelle Kotze.

Rainbow Rare Earths
Rainbow Rare Earths CEO Martin Eales.

Originally financed by Africa focused natural resources and energy group Pella Resources, which remains the largest shareholder, Rainbow Rare Earths is underway with the development of the fast-to-market, low capex, high-grade rare earth elements Gakara project in Burundi.

Rainbow Rare Earths’ Gakara project is one of the highest grade rare earths projects globally – with first production and sales of rare earth oxide concentrate expected by end-2017.

The magnet rare earths-rich Gakara deposit is located 20 km south-southeast of Bujumbura, Burundi’s capital city, and is estimated to have one of the highest grades of rare earths – grading at between 47-67% total rare earths oxide (REO) – with a basket comprising of the following rare earth elements (REE) based on content:

  • 46 % cerium
  • 31% lanthanum
  • 16% neodymium
  • 5% praseodymium; and
  • 2% other.

Based on the average grades of REO within Gakara, magnet rare earths (principally neodymium, praseodymium and dysprosium) account for approximately 22% of the contained REOs within the Gakara ore.

It is these rare earths that are of great value to Rainbow Rare Earths because, based on current rare earths market prices, the company will be able to yield the most revenue from its magnet rare earths.

“Despite accounting for a relatively small percentage of the total REE basket, our magnet REEs are expected to yield the most value for us,” Eales notes, adding that based on the average samples of the vein material, the magnet REEs within Gakara represent an average of approximately 80% of the contained value of REOs at current market prices.

Historic production

Not a new discovery, Eales explains that the Gakara project was discovered in 1936 by Somuki, a private Belgian company, and was mined periodically between 1948 and 1978 by Somuki and Sobumines – a joint venture company between another private Belgian company and the Burundi government.

Rainbow Rare Earths
Rainbow Rare Earths' Gakara project is poised to be the next REO concentrate producer outside of China once in production.

During this time, about 5 000 t of  +50% REO ore was mined from 14 different sites and the product – grading at between 66% - 71.5% total REO – was sold to French chemical and pharmaceutical company Rhone Poulenc and Berlin-based chemical factory Th Goldschmidt AG – founded by chemist Theodor Goldschmit – who trained as a colourist, a specialist in dyeing textiles.

Historical mining at the site demonstrated the consistency of the grade and mineralisation of the concentrate whilst also providing significant detail and validation of the vein/stockwork rare earth mineralisation system.

It was this historic data, combined with further exploration work undertaken by Rainbow Rare Earths between 2011 and April 2013 that gave the company enough confidence in the mineral prospectivity of Gakara.

Recent exploration work

Exploration work undertaken during this time included mapping of geological traverses, geophysical and geochemical orientation surveys and the collection of 150 grab samples from REE veins which were submitted for analysis by South Africa-based independent laboratory ALS Chemex.

The samples analysed yielded consistently high grades with an average of approximately 58% total REO at a range of between 47% and 67% total REO.

Rainbow Rare Earths
The magnet rare earths-rich Gakara deposit is located 20 km south-southeast of Bujumbura, Burundi's capital city.

More recent exploration and development work by Rainbow Rare Earths included detailed mapping of two localities within the mining licence, namely Gasagwe and Gashirwe West; mineralogical and gravity separation test work; hydro-metallurgical studies; design of a processing plant; and a conceptual mining study based on a trial bench mining exercise at the two localities.

In September 2016, Rainbow Rare Earths commissioned The MSA Group as its independent consultant to prepare an independent competent person’s report on the project.

Despite considerable historic mining activities and more recent exploration work, the Gakara project is considered by The MSA Group to be an exploration target, as defined in the JORC Code, as a result of insufficient exploration data to estimate a mineral resource as well as REE vein characteristics that are hard to quantify.

Accordingly, The MSA Group calculated an exploration target of between 20 000 t and 80 000 t of mineralised vein material grading at 47% - 67% total REO.

Based on this, Rainbow Rare Earths decided not to take the Gakara deposit to a JORC resource but mine it as is in the meantime over the next two to four years, until it becomes economically viable to prove the resource up further.

Rainbow Rare Earths was granted a 25 year renewable mining licence by Burundi ministries of Energy, Mining and Economic Development in March 2015 – subsequently ratified by presidential decree in April 2015 and June 2015.

This was followed by an oversubscribed US$8 million fundraising and successful IPO on the LSE on 30 January 2017, the company was able to raise the required funding to purchase the mining equipment and construct the processing facilities necessary to commence trial mining activities and bring Gakara into production as well as provide for working capital and general corporate purposes.

In addition to this, the funds also enabled Rainbow Rare Earths to repay private equity and venture capital firm Pala Investments $1.7 million in full and final settlement of the outstanding loan facility, leaving Rainbow Rare Earths debt free.

Trial mining phase

During the 22-month trial mining phase, Rainbow Rare Earths intends to mine 5 300 t of ore and produce 3 900 t of concentrate for sale.

At the company’s first production site – Gasagwe – it plans to produce 3 338 t of ore for 2 503 t of concentrate.

Trial mining is already underway at Gasagwe, with haulage and access road construction being a primary focus as well as the establishment of the basic infrastructure for the mine site.

A local labour force has also already been recruited and initial extraction of run-of-mine (ROM) ore from the high-grade veins has commenced by means of manual bench mining of 1 m ‘steps’ to expose the veins.

The quantity of ore mined was increased when the company took delivery of its first fleet of mining machinery at the end of April.

A backhoe-trailer combination will be used to remove the bulk of free digging waste; this will enable minimal mining dilution of the run of mine ore owing to the ease of extraction of the veins.

Gashirwe West, the second deposit to be mined, is situated on the central north-west part of the mining licence. Planned production from this deposit will begin in month 13 of 22, according to the trial mining plan. Trial mining at this deposit will extract 1 933 t of ore for 1 379 t of concentrate.

This will be done by means of underground up-dip room and pillar manual mining accessed through hand dug adits.

Assuming the first phase of trial mining is successful, Rainbow Rare Earths intends to ramp-up production to 5 000 tpa (420 tpm). The success of the trial mining phase will be monitored on an on-going basis and may allow early production from new mining locations.

The ROM ore produced from Gasagwe will be stockpiled for approximately six months prior to commissioning of the ore processing plant.

Processing

Rainbow Rare Earths has signed a full engineering, procurement and construction management (EPCM) contract with South Africa-based Obsideo Consulting for the design, supply and construction of its ore processing plant with a capital equipment value of approximately US$1.5 million.

The processing plant will have a 10 tph capacity and is capable of ramping up to well beyond 5 000 tpa.

The ROM ore will be subjected to gravity separation by means of crushing, screening, jigging and shaking table process to produce concentrate, through the use of a standard off the shelf components.

Off-take secured

Rainbow Rare Earths has signed a distribution and off-take agreement with German technology and materials company subsidiary tk Raw Materials – part of ThyssenKrupp.

This off-take agreement has an initial ten year commercial term for 5 000 tpa of rare earth concentrate or the downstream products resulting from this concentrate. tk Raw Materials also has a first right of refusal over the next 5 000 tpa of product.

The company will also act as the exclusive worldwide sales agent of the REO product from Gakara on behalf of Rainbow Rare Earths.

Future

Poised to be the next REO concentrate producer outside of China once in production, Rainbow Rare Earths is confident that the Gakara project will be able to yield many more REO tons than noted in the competent person’s report. Besides the 798 occurences of high-grade vein material already identified to date, Eales believes that the progress of mining activity will reveal further occurrences.

Minerals processing excellence

Minerals processing specialist Metanza in partnership with South Africa-based engineering consultancy Obsideo Consulting assisted Rainbow Rare Earths from test work right through to implementation at its Gakara rare earths project in Burundi.

For the Gakara project, minerals processing test work, which included crushing, jigging, shaking table, up-current classifier and filter tests, was conducted at the Metanza Metallurgical Laboratory in Randburg, Johannesburg.

Metanza also carried out the process plant design and is supplying the concentrating jig. Metanza’s services include commissioning of the plant and training of plant personnel on site in Burundi, while Obsideo Consulting is currently implementing the project on an EPC basis.

The rare earths processing plant was designed with a modular approach to allow for ease of fabrication and on-site assembly, with select equipment to be supplied by MPTeq.

Driven by demand

Demand for magnet rare earths is driven by the automotive industry for use in electric and hybrid motors and generators as well as for use in wind turbines, computer drives electronics such as mobile phones, mp3 players and cameras, and in sensors and medical imaging (MRIs).

Feature image shows a mineralised sample of Bastanesite 

All images courtesy of Rainbow Rare Earths