Arafura Resources will, in the next few years, become a long-term, secure supplier of neodymium and praseodymium (NdPr) from its 100%-owned Nolans project. The project site is located 135 kilometres north along the Stuart Highway from the town of Alice Springs in the Northern Territory, Australia.
Arafura’s mineral tenure over the Nolans project site is secured by three granted exploration licences (ELs) - EL28473, EL28498 and EL29509. Arafura has also applied for four mineral leases (MLs) within these ELs which, when granted, will host the mining and mineral processing operations, and many of the associated infrastructure elements of the Nolans project.
Geology and Resources
The project’s cornerstone asset is the Nolans Bore rare earths-phosphate deposit, one of the largest and most intensively explored deposits of its kind in the world. The deposit contains a JORC 2012-compliant Mineral Resources of 56 million tonnes at an average grade of 2.6% total rare earth oxides (TREO) that extends to 215 metres below the surface. Two-thirds of the contained rare earths are in high confidence Measured and Indicated resources.
Mineral Resources for the Nolans Bore deposit as at 7 June 2017 using a 1% TREO Cut-Off Grade
|RESOURCES||TONNES million||RARE EARTHS TREO %||PHOSPHATE P2O5 %||NdPr enrichment %|
Numbers may not compute due to rounding. “NdPr enrichment” is the proportion of TREO comprising Nd2O3 and Pr6O11.
The most abundant rare earth-bearing minerals at Nolans Bore are apatite, monazite (both phosphate minerals) and allanite (a silicate mineral). These mineral species present a highly desirable rare earth mix at Nolans Bore, with 26.4% of the mix represented by NdPr.
Mining and Mineral Processing
The Measured and Indicated resources base has the potential to support mining and processing operations for at least 30-35 years, at a design capacity of 14,000 tonnes of TREO equivalent per annum.
Open-cut mining will selectively target phosphate-rich material types which comprise more than two-thirds of the deposit’s Measured and Indicated resource inventory. Arafura is planning to mine up to five million tonnes each year to produce 650,000 tonnes of run-of-mine (ROM) ore as feed to a three-stage crushing circuit.
Crushed ore will initially be processed in a beneficiation plant that employs whole-of-ore flotation as the main unit operation. Beneficiation reduces the mass for subsequent processing by around 50%.
The flotation concentrate will be pumped approximately 8 kilometres via a slurry pipeline to an extraction plant.
The former product will be further refined at a separation plant into three final products for sale: NdPr oxide, lanthanum (La) oxide, and a mixed middle-heavy rare earth (SEG-HRE) carbonate. Annual production is estimated to be 3,600 tonnes of NdPr oxide, 2,660 tonnes of La oxide and 660 tonnes of SEG-HRE concentrate. Arafura is currently examining two options for the location of the separation plant: 1) the Nolans site; and 2) at a site in South Korea in a potential joint venture with OCI Company Ltd.
Solid rare earth-bearing products from pre-leach will then be subjected to several processes at the extraction plant that involve baking, water leach, precipitation, dissolution, and purification. Output from the extraction plant will be 16,450 tonnes per annum of a NdPr-rich rare earth chloride intermediate product, and a lower value cerium (Ce) oxide product.
The former product will be further refined at an offshore separation plant into three final products for sale: NdPr oxide, lanthanum (La) oxide, and a mixed middle-heavy rare earth (SEG-HRE) carbonate. Annual production is estimated to be 3,600 tonnes of NdPr oxide, 2,660 tonnes of La oxide and 660 tonnes of SEG-HRE concentrate. Arafura is assessing a site for the separation plant in the Saemangeum Free Economic Zone in South Korea in a potential joint venture with OCI Company Ltd.
Arafura’s focus during 2018 is to complete validating the performance of the Nolans process flowsheet through the completion of seven consecutive pilot operations. These pilot operations are providing process, mechanical engineering design and materials handling data for incorporation into the Nolans Definitive Feasibility Study, scheduled for completion at the end of 2018.
As of August 2018, four of the seven pilot phases were complete (Beneficiation; Phosphate Extraction; Bulk Pre-Leach; Acid Bake) and results to date have met the Company’s performance expectations. Vision of the various phases of the pilot program can be viewed here..