ASX-listed Peak Resources has announced that its mineral concentrate has been graded at 52.9% rare earth oxide (REO), more than three times the concentrate grade of 16.3% REO assumed in the March 2014.
“A very high grade mineral concentrate has been produced from a sample of Ngualla’s weathered bastnaesite mineralisation during test work at specialist rare earth institutes in China. The testwork in China was commissioned by Peak as part of the overall beneficiation development work programs which are also in progress at facilities within Australia,” Peak Resources said in a statement.
This outstanding result ranks Peak as one of a select number of projects in the world able to achieve such high mineral concentrate grades. The higher grade and lower mass concentrate has significantly reduced iron content that will potentially lead to further reductions in operating and capital costs for the subsequent leach recovery stage of the operation.
Progressing beneficiation development
Meanwhile, Peak has continued to progress the beneficiation development program since the completion of the Preliminary Feasibility Study (PFS) in March 2014 and the Beneficiation Breakthrough success of August by commissioning further testwork at two specialist rare earth institutes in China in addition to continuing work at the Australian test facilities.
“The focus on beneficiation improvements has been maintained, as the ability to produce a high grade concentrate has a profound impact on the downstream process and has the potential to reduce both the operating and capital costs of the project,” the company said.
The mineral concentrate produced by this new testwork has an REO grade of 52.9% REO at an REO recovery of 52.1%, significantly higher than both the PFS assumption of 16.3% REO (70.2% REO recovery) and the August 2014 ‘Beneficiation Breakthrough’ grade of 34.4% REO (52.0% REO recovery).
Focusing on target recovery improvements
A significant additional benefit of this flowsheet is the effective depletion of acid consuming iron from the concentrate, which is expected to further reduce downstream acid requirements. With an upgrade of 8.9 times the feed sample grade of 5.93% REO used in this test and the concentrate now represents a mass of only 5.9% of the initial feed.
The effective use of low cost, physical separation techniques in the new testwork to successfully remove 53% of the feed mass before flotation reduces flotation reagent usage. The flotation process also uses lower cost reagents and ambient temperatures compared to the ‘Beneficiation Breakthrough’, which requires a temperature of 60°C.
The newly developed beneficiation process will be tested in parallel on additional samples at laboratories within Australia. Further optimisation of the flowsheet is planned in China on additional samples of weathered Bastnaesite Zone mineralisation and will target improved recoveries.