Caula is projected to be a low-cost vanadium & graphite supplier to the fast-growing vanadium-flow and lithium battery markets, with particular focus on electric vehicles and energy storage systems.
The high grade of Caula graphite will enable New Energy Minerals to generate a top-quality product at a low cost, maximising margins and providing protection against price volatility. Additionally, results indicate that the project can also concurrently produce high-value vanadium products and a scoping study of the Caula project has been completed, confirming exceptional economics. New Energy Minerals’ subsequent definitive feasibility study (DFS) will build on the scoping study results and is targeted for release in H1-2019.
The Caula Vanadium-Graphite Project
The Caula Vanadium-Graphite Project is focused on critical commodities for the lithium and vanadium battery markets, next generation steel and fire resistant building materials. New Energy Minerals is currently fast-tracking this world-class project which hosts a JORC (Measured) mica-hosted vanadium resource of 22Mt @ 0.37% V2O5 (0.2% cut-off) for 81,600 tonnes of vanadium pentoxide (180 million pounds) with high grade intersections up to 1.9% V2O5
Caula also hosts, within the same deposit, one of the highest- grade graphite deposits in the world, a JORC (Measured) graphite deposit of 21.9 Mt @ % 13.4% TGC (8% cut-off) for 2,933,100 tonnes of contained Graphite, with high grade intersections of up to 29% TGC. The Company expects Phase 1 trial mining and processing to commence during H2-2019, which will provide early cashflows.
Caula Vanadium-Graphite Resource Estimate
The current Caula Mineral Resource estimate is based on 16 diamond drillholes totalling 2,233.21 metres (484.72m in 2016 and 1,748.49m in 2017) and one reverse circulation (RC) drillhole totalling 99 metres. Drillholes are spaced approximately 85 metres apart along a 540-metre strike length. With the exception of drillhole MORC004 (-77°), all holes were drilled at inclinations of between 55° and 60° from the horizontal.
The Measured Vanadium-Graphite Mineral Resource totals 22 million tonnes at an average grade of 0.37% V2O5 and 13.4% TGC for 81,600 tonnes (180 million pounds) of V2O5 and 2,993,100 tonnes of contained Graphite.
Caula V2O5 Deposit as of 17 July 2018 (0.2 % V2O5 Cut-off)
|Resource Block||Volume||Density||GTIS||Average Grade||Contained V2O5||Resource Category|
|(M m3)||(ton/m3)||(Mt)||(% V2O5)||(tonnes)|
Caula Graphite Deposit as of 23 July 2018 (8.0 % TGC Cut-off)
|Resource Block||Volume||Density||GTIS||Average Grade||Contained Graphite||Resource Category|
|(M m3)||(ton/m3)||(Mt)||(% TGC)||(tonnes)|
The New Energy Minerals Caula Vanadium-Graphite project is located in an area with proven resources and is along strike from nearby world-class deposits – including those developed by Syrah Resources Ltd (SYR:ASX), a company valued at ~A$1 Billion. Situated in Cabo Delgado Provide, Northern Mozambique, the project has excellent transport infrastructure with a ~25km access road, connecting to a sealed road, which leads to the ports of Pemba and Nacala.
The democratically elected Mozambique government, recognises the importance of the mining industry to the nation’s economic growth, and is highly supportive of businesses that enhance productive sectors of the economy, and contribute to economic diversification.
The Country’s natural resources have already attracted major investors, including the mining groups Vale (Brazil), BHP (Australia-UK), American oil and gas giant Exxon Mobil, and numerous members of the U.S and Japanese private sector eager to invest in new natural gas projects.
To further improve the country’s business climate, the Mozambique government has partnered with the Word Bank, most recently securing US $1.7 billion in funding from the International Development Association. The funds, scheduled for allocation between 2017 and 2021, will stimulate the private sector, leveraging its key branches, including the energy sector and the full agricultural value chain.
Processes & Metallurgy
The Caula Vanadium-Graphite deposit (and the deposits along strike to the South of Caula, including the Syrah Balama deposit) represent a unique opportunity to replicate the success achieved by American miners in the early 20th century, by using a simple and proven process to extract Vanadium.
20th Century Vanadium Mining in the United States
In the United States Colorado Plateau, between 1910 and 1955, there were several operations producing vanadium from micaceous ores, particularly from ores containing Roscoelite mica, a near surface vanadium deposit which consist of sandstone impregnated with vanadium mineral, which is the same mineral that hosts the Caula Vanadium. Roscoelite, the vanadium mica, is the principal ore mineral which occurs as minute flakes coating the grains of sand, and partly or completely filling the pore spaces between grains.
During the period, a number of techniques were used in the recovery of Vanadium. As the ore was crushed and ground, Mica flake were often recovered by screening and through means of froth flotation. Mica concentrates were also calcined and then leached as a form of extraction.
A range of processing conditions were used in the treatment of concentrates. In some operations, a salt roast was followed by a water leach, whereas in others, the mica was roasted with other additives such as calcium sulfate and then acid or alkali leached to dissolve the Vanadium.
Given the relative simplicity in the processing and treatment of these mica-vanadium deposits, the United States was propelled to become the world’s largest Vanadium producer by 1941. The majority of these deposits, especially the ones with low uranium content, have since been mined out since and production shifted to VTM deposits in South Africa and elsewhere.
New Energy Minerals Metallurgy Testwork
A total of eight campaigns of mineral processing testwork have been completed on the ore from Caula. These include:
- Preliminary graphite testwork
- Graphite flotation testwork (IMO Perth, Nagrom Perth and SGS)
- Ore sorting testwork
- WHIMS and flotation testwork for vanadium (IMO and Nagrom, Perth)
Graphite concentrate recovery testwork results have been highly positive and all programs have delivered high-grade concentrates, with greater than 95% total graphitic carbon, with grades up to 98.7% TGC and average concentrate grades of >97% for all ore types (see table below). Furthermore, the concentrates produced have contained commercially significant proportions of larger flake sizes (flake sizes larger than 0.18 mm). Good recoveries to concentrates have been achieved at coarse grinds (i.e. 80 percent passing sizes greater than 0.5 mm).
|Graphite Product||Size Fraction (μm)||Fresh Sample||Transitional Sample||Oxide Sample|
|Mass (%)||TGC (%)||Mass (%)||TGC (%)||Mass (%)||TGC (%)|
|Jumbo||300 to 500||26.1||97.82||25||98.66||10.6||97.64|
|Large||180 to 300||36.4||97.43||36.6||98.64||34.7||97.7|
|Medium||150 to 180||9.5||96.96||10.3||98.46||14.8||97.76|
|Small||75 to 150||18.4||96.85||20.5||98.42||34.7||97.78|
Preliminary vanadium testwork has produced outstanding recovery and concentrate results, from bench-scale metallurgical testwork, on ore from the Fresh Zone of the Caula Vanadium-Graphite Project in Mozambique. Through the integrated graphite and vanadium flowsheet, the testwork utilised Wet High Intensity Magnetic Separation (WHIMS) on composite samples, which resulted in a Cleaner Concentrate grade of 1.66% V2O5, with a recovery rate of 80.6%. Results were achieved from an overall feed grade of 0.401% V2O5, before graphite extraction.
Highlights of initial testwork include:
- The results of the rougher WHIMS followed by cleaner WHIMS achieved an 80.6% recovery to a concentrate grade of 1.66% V2O5.
- Scavenging the rougher and cleaner tailings delivered a further 10.2% recovery to a scavenger concentrate grade of 0.67% V2O5.
- Combining cleaner and scavenger concentrates gives an overall recovery of 90.8% to a combined concentrate grade of 1.42% V2O5 from this simple open circuit test.
- Results were achieved from an initial composite feed grade of 0.401% V2O5, prior to graphite extraction through flotation.
- A full-scale commercial circuit could employ more stages of cleaning and scavenging, and intermediate products such as cleaner tailings and scavenger concentrates could be recycled to achieve improved concentrate grades and recoveries.
- This initial testwork has shown that high vanadium concentrate grades and recoveries can be achieved from the tailings of the graphite flotation process through the WHIMS process.
- Quantitative mineralogy studies are underway to investigate mineral associations in vanadium concentrate, with the initial results confirming the micaceous nature of the concentrate.
The Company is progressing with additional testwork, which will produce a bulk sample of high-grade graphite concentrate for evaluation of downstream processing characteristics. Tailings from this graphite flotation work will be used in additional vanadium concentrate recovery tests, including testing of the weathered and oxidised material.
Quantitative mineralogy studies are also underway to investigate mineral associations in vanadium concentrate, with initial studies confirming micaceous nature of the concentrate. The extraction process for vanadium from mica is significantly different to vanadium extraction from vanidiferous titanomagnetite magnetites (VTM). The vanadium extraction process from micas, has closer parallels to the processes associated with lithium extraction from micas and clay minerals.
One example of Lithium extraction from a micaceous concentrate typically involved concentration of zinnwaldite (lithium mica) through a WHIMS process. The concentrate is then roasted at a temperature 850oC with sodium sulphate to break the mica crystal structure. The roasted product is subsequently leached with hot water to recover the lithium into solution. This type of roasting differs to conventional VTM concentrate processing, where higher temperatures (e.g. 1,150 oC) are required and SiO2 may cause problems with roasting. Another example of lithium recovery from a clay mineral involves roasting the ore with calcium sulfate to make the lithium amenable to hot water leaching.
The Company aims to conduct metallurgical tests including bench-scale roasting and leaching testwork to produce vanadium pentoxide with a minimum 98.5% purity.
Vanadium recovery from vanidiferous micas, including Roscoelite is well documented and a number of extraction processes have been established. One example involved roasting a micaceous ore at 850 oC with an addition of 3 to 5% of calcium sulfate. This was followed by vanadium dissolution by a carbonate/bicarbonate leach.
All the current and planned testwork is geared towards optimising the beneficiation process and establish a robust, low-cost flowsheet for both graphite and vanadium extraction as well as vanadium downstream beneficiation.