Battery Hub, WA (100%)
Electrolytic manganese, cobalt
The Battery Hub Project is located 120km to the south-south-west of Paraburdoo, 200km north-east of Gascoyne Junction and 330km east of Carnarvon in Western Australia. The tenements are located 30km north-east of Mt Augustus, a well-known tourist destination which has an unsealed airstrip and year-round accommodation facilities. A maintained gravel road runs from Mount Augustus to the property.
Figure 1: Location and key manganese prospects identified
No exploration had been undertaken at Battery Hub until 2010, when Aurora Minerals Ltd began an extensive mapping, sampling and drilling program. Aurora’s efforts resulted in numerous manganese prospects being identified over most of the 70km strike length on the tenements. Aurora surrendered the project in 2015 due to weakness in the manganese market. All drill sites were rehabilitated.
Since late 2017, Pure Minerals has re-interpreted the historic exploration with additional mapping, drilling and metallurgical test work with the new objective of producing high-purity manganese products to the burgeoning battery metals sector.
Drilling completed in early 2018 was focussed on the Pools, Julia, Steven Ridge and Isle prospects. High grade manganese mineralisation exceeding 30% Mn was identified at all prospects, confirming previous mapping that identified manganese mineralisation extends over a large area.
Moreover, the Pure Minerals discovered a previously-unrecognised cobalt credit in all prospects and in all identified types of manganese mineralisation. Cobalt grades in drilling exceeded 0.10% Co in places.
Proof-of concept metallurgical test work completed in 2018 on composite drilling samples shows that the manganese and cobalt mineralisation displays excellent leaching recoveries (>95%) and kinetics. Battery Hub could produce high-purity manganese products such as manganese sulphate, electrolytic manganese dioxide (EMD) and electrolytic manganese metal (EMM) and cobalt.
Manganese sulphate is primarily used in the agricultural sector as a soil additive, especially in situations when high rates of phosphate fertiliser are used in the soil. It is also a precursor to EMM, EMD and many other chemical compounds. EMD and EMM are both used in the production of rechargeable EV batteries in association with lithium, cobalt and nickel.
The Battery Hub project now has the potential to be a significant source of two of the main cathode materials used in rechargeable batteries – electrolytic manganese and cobalt.
Geology and Mineralisation
Three major forms of manganese mineralisation have been identified at Battery Hub:
- Stratiform deposits
- Laterite/detrital deposits
- Quartz manganese breccias
Stratiform mineralisation is the dominant exploration target at Battery Hub given its tonnage potential. Manganese mineralisation is associated with shale/siltstone units of the Ullawarra Formation of the Middle Proterozoic Edmund Group, hosted within the Bangemall Basin. The Ullawarra Formation is tightly folded and faulted, but generally the manganese horizons are relatively undeformed and shallowly dip northward.
Up to four main manganiferous horizons have been identified over the 70km strike length of the Ullawarra Formation. Some of the siltstone crops out as interbedded shale and manganese, with some high-manganese beds grading up to 50% near surface.
Figure 2: Outcropping ridgeline of stratiform manganese-cobalt mineralisation (Pools prospect)
The entire sediment package appears to exhibit a background manganese grade of 0-5% Mn. Drilling by Pure Minerals indicated individual sample intervals exceeding 30% Mn and 0.05% Co. High-grade zones are variable down-dip and along-strike; however, the overall mineralised zones are consistent and continuous.
Figure 3: Cross section of manganese-cobalt mineralisation in the Pools prospect
Lateritic/detrital deposits are considered preserved remnants of a much larger widespread laterite peneplain. The laterite consists of massive and pisolitic ironstone and ferruginous silica, with variable manganese content. Pure Minerals views these deposits to have the potential to be shallow and bulk-tonnage.
Figure 4: Drilling into outcropping detrital manganese-cobalt mineralisation
Drilling by Pure Minerals indicated individual sample intervals exceeding 30% Mn and 0.10% Co.
Figure 5: Cross section of weathered detrital manganese-cobalt mineralization at base of laterite (Isle prospect prospect)
Figure 6: Cross section of weathered detrital manganese-cobalt mineralization at base of laterite, including historic drill holes (Julia prospect)
Quartz-manganese breccia are either strike‐parallel or northeast trending cross-cutting veins. They are associated with higher-grade stratiform mineralisation, suggesting that they have a syn-genetic association with the stratiform deposits. Surface rock chip sampling indicated grades exceeding 40% Mn. These prospects have not been drilled by Pure Minerals.
Figure 7: Fault breccia outcrop of manganese-cobalt mineralisation at Battery Hub
Extensive Cobalt Mineralisation Identified in Drilling
Cobalt was never identified by previous operators and is typically ignored by laboratories testing manganese mineralisation. Once identified in metallurgical testing, Pure Minerals re-assayed its previous drilling for by-product cobalt with highly encouraging results (see Figure 8, below).
Figure 8: Select cobalt by-product intercepts identified in drilling.
Cobalt is associated with manganese in all drilled prospects and wherever manganese mineralisation is identified. Higher-grade cobalt by-product targets have been identified, such as the Isle prospect, where drilling intercepted 12m @ 0.068% Co, including 4m @ 0.114% Co.
Cobalt represents a potentially highly-valuable by-product in hydrometallurgical leaching scenario.
Metallurgical Test work
In June and September 2018, Pure Minerals released results of a metallurgical test work programs.
The objectives of the test work were to (a) determine whether the mineralisation appears amenable to leaching and the production of high-purity manganese sulphate, electrolytic manganese dioxide (EMD), electrolytic manganese metal (EMM) and cobalt by-product, and (b) determine whether the medium-grade manganese mineralisation can beneficiate to a marketable grade for steel industry consumption.
Pure Minerals engaged METS Engineering (“METS”) to design a proof-of-concept flowsheet that entailed crushing and screening, mineralogical test work using QEMSCAN analysis, heavy liquid separation and magnetic separation. Beneficiation test work was conducted by ALS Global laboratories, located in Western Australia. The CSIRO conducted proof-of-concept hydrometallurgical leaching test work.
Samples were sourced from multiple intercepts and drill holes within the Julia (detrital/lateritic) and Pools (stratiform) prospects that were selected to reflect a potentially “mineable” block of manganese-cobalt mineralisation. The Julia composite sample graded 10.8% Mn and 0.03% Co and the Pools sample graded 11.1% Mn and 0.02% Co.
Figure 9: Location of drill hole composite samples used in metallurgical test work
Key results from the test work included:
- Leaching test work exceeded expectations, with 95%-99% manganese recovery and 85%-90% cobalt recovery from both Julia and Pools.
- Exceptionally fast leach kinetics were identified, with leaching equilibrium met in less than 30 minutes
- Weak leach kinetics of contaminant iron indicates a higher-purity solution can be produced.
- Beneficiation test work indicated that the stratiform mineralisation is the most amenable to dense media beneficiation due to its lower iron content. Modelling metallurgical test work on stratiform samples suggests a 14.4% Mn grade sample can beneficiate to >32.0% Mn concentrate, which could be marketable to the steel sector. Such zones have been identified along the entire >70km strike length.
Overall, leaching test work confirms potential to produce high-purity manganese products and cobalt across the major types of mineralisation at Battery Hub.
Click here for preliminary beneficiation and mineralogical test results released 12 June 2018.
Click here for proof-of-concept leaching results released 5 September 2018.
The company’s strategy of suspending resource drilling until metallurgical test work was completed has enabled a far more efficient use of exploration capital going forward. Priority is now given hydrometallurgical processing to produce high-purity products for the battery metals sector, more so than producing manganese ore for the steel sector.
Further metallurgical work will focus on optimising reagent consumption and assess low cost hydrometallurgical routes.