Montero Reports 94 to 97 percent Total Rare Earth Recoveries in Metallurgical Testing at Wigu Hill

Montero Mining and Exploration (TSXV:MON) reported receiving positive results from bulk leach testwork completed on samples of REE bearing concentrate from the Wigu Hill project in Tanzania. Mintek reported extraction recoveries of between 94 percent and 97 percent total rare earth elements, indicating very promising leaching efficiencies.

As quoted in the press release:

Montero has completed a series of mineral processing and hydrometallurgical testwork programs. Bulk samples of the bastnaesite-rich carbonatite were used by Mintek and SGS Laboratories for mineralogical analysis, mineral processing and hydrometallurgical testwork. Mineral processing testwork included x-ray sorting (see news release 01/02/2012) and froth flotation (see news release 29/7/2013) aiming to produce a high grade REE mineral concentrate. The principle focus for all test work programs is to develop an economic process to deliver saleable REE products and as such the hydrometallurgical testwork at Mintek has been successful in achieving this result.

Mintek developed a 3-stage hydro-metallurgical leach process and was asked to optimize this process. Additional sample material was sent to Mintek for this purpose and assaying of the bulk sample returned a value of 11.01% TREE.

The optimized results from Mintek on three samples concluded:

“The first stage is a gangue acid leach to reduce the carbonate content, which successfully reported approximately 55% mass loss for all the gangue leach tests done, but with minimal rare earth losses. The second stage (caustic crack stage) was successful in the removal of 71% of the silica in the samples, and the precipitation of the rare earths as hydroxides with minimal TREE losses. The third and final stage (a reductive acid leach stage) established that 94% to 97% of the TREE’s can be recovered into the leach solution and from this, precipitation to provide a Mixed Rare Earth Oxide (MREO) concentrate for refining.”

The final phase of the hydrometallurgical teswork is solvent and ion exchange to prepare individual purified REE products. Mintek has developed a rare earth solvent extraction pilot plant for this purpose and Montero has delivered a 1.5 tonne bulk sample to Mintek to further define the final stage REE extraction processing.

Montero president and CEO, Dr. Tony Harwood, said:

Recently performed bulk leach metallurgical testwork returned excellent results with high leach efficiencies achieving recoveries of 94% to 97% TREE reported from REE bearing carbonatite dikes from Wigu Hill. Montero continues to seek a partner to advance Wigu Hill to a mining stage, similar to our phosphate project, which is funded to pre-feasibility and bankable feasibility study stage.

Click here to read the Montero Mining and Exploration (TSXV:MON) press release