This edition of Bulls N’ Bears Big Hits singles out an exceptional discovery, instead of the usual fare of notable intercepts recently revealed on the ASX. Patriot Battery Metals’ latest caesium discovery in Quebec, Canada, includes a best hit of 5 metres at 13.2 per cent caesium oxide, including 2m at 22.9 per cent oxide, while another hole produced a top grade in 1.1m at 26.61 per cent caesium oxide.
Let’s dive in.
Patriot Battery Metals (ASX: PMT)
Shaakichiuwaanaan project, James Bay, Quebec.
Best overall hit: 5m at 13.2% caesium oxide, including 2m at 22.9% oxide.
Second best hit: 11.1m at 4.87% caesium oxide, including 7.1m at 7.39% oxide.
Best grade: 1.1m at 26.61% caesium oxide
Patriot Battery Metals has landed on some massively over-limit caesium assays from drilling at its Shaakichiuwaanaan lithium exploration project in the James Bay area in the Canadian province of Quebec.
Latest results show the company intercepted thick, high-grade caesium while drilling at two distinct zones 285 metres apart in the company’s main CV13 pegmatite, including four top intercepts above 22 per cent caesium oxide.
Based on their comparative per cent multiplied by intercept metres from both primary and included intercepts, the top intercept came from the smaller but higher-grade Rigel zone, where Patriot hit 5m at 13.32 per cent caesium oxide, including 2m at a second highest grade of 22.90 per cent.
The second-best intercept came from the larger Vega zone, which delivered 11.1m at 4.87 per cent caesium oxide, including 7.1m at 7.39 per cent.
The longest intercept also came from Vega and showed exceptional thickness for a caesium occurrence, with a run of 18.1m at 2.71 per cent caesium oxide, including 7.4m at 5.45 per cent.
The fourth-best hit came from the Rigel zone, which also produced the third-highest included caesium oxide result. The total run comprises 5.9m at 11.19 per cent caesium oxide, including 1m at 22.69 per cent.
The Vega zone also delivered a next best intercept of 5.7m at 4.97 per cent, including 3m at 8.20 per cent.
The outright best grade came from Rigel’s next hole, which bored through 3.2m at 10.24 per cent caesium oxide, including 1.1m at an astounding 26.61 per cent.
Additionally, a channel sample at Vega ran 3m at 9.43 per cent caesium oxide, including 1m at 22.41 per cent oxide.
The Vega zone of enrichment can be traced through the drilling program over a 600m by 400m area that ranges from 1m to 10m thick and remains open.
The Rigel zone coincides with a pronounced structural flexure in the CV13 pegmatite and is estimated from drilling to be at least 200m by 80m and up to about 5m thick.
Early last month, Patriot flagged caesium results from drill testing that exceeded the caesium detection limit of 10,000 parts per million (ppm) caesium for the available analytical package - that is more than 1 per cent caesium, or more than 1.06 per cent caesium oxide. The conversion factor for caesium-to-caesium oxide is 1.0602.
The caesium levels in Patriot’s deposit are remarkable, given that the average background level of caesium in the Earth’s rocks is relatively low at about 3ppm or 0.0003 per cent.
More specifically, granites typically contain about 1ppm or 0.0001 per cent caesium, while sedimentary rocks average 4ppm or 0.0004 per cent oxide. Accordingly, caesium is considered a rare element.
Within the more common pegmatitic host rocks for caesium, the average level of caesium may vary significantly, but studies suggest an average of about 1106 ppm or 0.1106 per cent caesium oxide.
Some pegmatites can carry higher average levels, which can reach up to 5057 ppm or 0.5 per cent caesium oxide, such as at Western Australia’s well-known Mt Edon pegmatite field, 430 kilometres north-northeast of Perth near Payne’s Find.
Patriot Battery Metals drill core from a hole at the Rigel target in Canada shows semi-massive to massive pollucite (red box), grading 17.95% caesium oxide over 3.7m, including 22.9% caesium oxide over 2m. Credit: File
Caesium is typically associated with other rare elements such as lithium and tantalum and is one of the key “fertility” indicator elements that define lithium-caesium-tantalum pegmatites as being favourable for the other two critical metals, among others such as rubidium.
Everest Metals Corporation has defined a rubidium resource estimate at Mt Edon of 3.6-million-tonnes at 0.22 per cent rubidium oxide and 0.07 per cent lithium oxide at a 0.1 per cent rubidium oxide cut-off grade.
Rubidium is an alkali metal, in the group comprising lithium, sodium, potassium, rubidium, caesium, and francium on the periodic table of elements. All the alkali metals are known for their soft, silvery appearance and high reactivity. All the alkalis react violently in air or water and, as a result, they tarnish and oxidise rapidly to oxides and/or hydroxides on exposure.
As a result of their reactivity, none of the alkali metals are present in the earth’s geological profile as a native metal and are usually recovered in processing as oxides, carbonates or hydroxides.
Due to its high reactivity, caesium is classed as a hazardous material and is typically stored and shipped in dry, saturated hydrocarbons, such as mineral oil. It can be handled only under an inert gas, such as argon.
Caesium has only one stable isotope, caesium-133, and is mined mainly from its principal ore mineral, pollucite, a hydrated alumino-silicate mineral found most commonly in pegmatites.
Patriot has identified pollucite by X-ray diffraction in its project and attributes the mineral as being the primary source of the caesium enrichment, based on the very high caesium grades and geological logging.
The high-grade caesium intercepts indicate that semi-massive to massive pollucite is present, especially in the high-grade Rigel zone where several 10 per cent to 20-plus per cent caesium oxide intercepts are present.
The company has kicked off mineralogical studies on the Vega and Rigel caesium zones to confirm the presence and quantify the abundance of pollucite and, to a lesser extent, on a pink lithium mica lepidolite.
Pollucite resembles quartz and is often associated with lithium-rich minerals, such as lepidolite and petalite. Patriot’s project presents the same association.
Caesium has a wide and steadily increasing variety of uses. Since the 1990s, the most prominent application of caesium has been as caesium formate for drilling fluids to increase the fluid's density. A concentrated solution of caesium formate has a density 2.3 times the density of fresh water.
The metal also finds extensive but specific use in other applications, including in highly accurate atomic clocks, which have become essential components of the internet, cellular devices and global positioning systems.
It is also employed in photoelectric cells due to its capacity to lose electrons when struck by light and as a “getter” to remove residual trace gases in vacuum tubes. It also finds use in the production of optical glasses and can be used as a catalyst in the hydrogenation of organic compounds.
The radioactive isotope, caesium-137, has applications in medicine, including radiation therapy and in industrial gauges such as thermometers and in hydrology to measure flow rates.
Economically viable caesium deposits are of high value but are very rare globally and usually occur at a smaller scale in a resource range of 10,000 tonnes up to 350,000t. They are typically identified in drill intercepts from 3m to 10m thick.
Sinomine Resource Group’s Tanco mine in Manitoba, Canada, is believed to be the world's biggest known source of caesium and is estimated to contain about 350,000t of the host mineral pollucite, currently representing over two-thirds of the world's known caesium reserves.
The relatively small scale of caesium resources stands in stark contrast to the world’s biggest pegmatite-hosted lithium deposits, which often range from 10Mt to more than 100Mt of ore.
Most notably in the context of Patriot’s discovery of exceptionally high grades of more than 26 per cent, the Tanco mine reports grades as high as 13.83 per cent caesium oxide.
Due to its scarcity and specific usage, the market price of high-purity caesium metal is hard to determine and varies greatly according to the form and amount required.
Principal compound forms, in descending order of demand, are as caesium formate; chloride and other halides, carbonate, nitrate and hydroxide, followed by various other forms. The pure metal is often offered in 1-gram ampoules of 99.8 per cent pure caesium.
No more than a few thousand kilograms of caesium chemicals are thought to be consumed in the United States each year and the nation is fully import-reliant for its caesium needs, with primary global producers estimated to include Canada, China, Germany and Russia.
Import and export data for caesium has not been available since the late 1980s and because caesium metal is not traded in commercial quantities, a market price is unavailable.
In 2023 a USGS mineral commodities summary indicated that one company offered 1-gram ampoules of 99.8 per cent (metal basis) caesium for $91.60, a 19 per cent increase from $76.97 paid in 2022; and 99.98 per cent (metal basis) caesium for $117, a 20 per cent increase from $97.86 paid in 2022.
At the end of September 2023, the prices for 50 grams of 99.9 per cent (metal basis) caesium acetate, caesium bromide, caesium carbonate, caesium chloride and caesium iodide were US$142.00, $98.10, $127.80, $143.40 and $163.80, respectively, with increases ranging from 5 per cent to 20 per cent compared with 2022 prices.
Another 2022 Wikipedia listing of pure element prices puts caesium metal at US$61,800 (A$95,790) per kilogram.
In 2024, the caesium market size was valued at US$363.58M (A$573M), with total revenue expected to grow at a compound annual growth rate of 6.5 per cent from 2025 to attain almost US$601.72M (A$949M) by 2032.
Caesium formate brines are typically rented by oil and gas exploration clients. After completion of a well, the used brine is returned and reprocessed for subsequent drilling operations, with almost 85 per cent of the brines recovered for reprocessing.
Patriot also nailed significant caesium results from its nearby 4.6km-long CV5 pegmatite, east of the CV13 pegmatite, with two best runs of 10.4m at 1.3 per cent caesium oxide, including 4m at 2.02 per cent; and 9m at 1.2 per cent, including 1.5m at 5.03 per cent.
The mineralisation appears to occur along the full length of the second hole. The distinct zones are less apparent than those at the two key caesium zones in the primary hole pegmatite and Patriot says further review and modelling is required to define the nature and extent of the zone, given the more open drilling density in that part of the project.
Patriot’s project currently hosts a combined lithium mineral resource estimate of 80.1Mt at 1.44 per cent lithium oxide in the indicated resource category and 62.5Mt at 1.31 per cent lithium oxide in the lower inferred category.
Patriot’s share price moved on last week’s caesium discovery announcement with an immediate jump from 19.5 cents on the company’s previous close to reach 24c on Thursday. The share price settled back to 23c today.
Caesium mineralisation of this scale and grade, especially in combination with high-grade lithium and tantalum, remains exceptionally rare globally and underscores the high-value critical mineral endowment of the geological system at Patriot’s project.
Considering caesium’s strategic importance and scarcity in global markets and its inevitable increasing use in key industrial and specialised applications, Patriot’s discovery has the potential to greatly enhance the project as a by-product.
Considering current international tensions between the US and China and Russia, any disruption of supply of this critical element could severely upset US industry and impede the development of crucial military hardware and new caesium lasers for its ballistic missiles.
As a result, the US and Canada agreed in December 2021 on a policy to lower the demand for precious minerals produced or regulated by China.
While Patriot’s sensational caesium discovery is at an early stage, it is sure to have lit a small fire under the company’s already considerable enthusiasm for the project as it presents a massive opportunity that could place the project among the top lithium-caesium-tantalite pegmatite assets globally.
The company intends to further evaluate the caesium opportunity as it continues to develop its Shaakichiuwaanan lithium project towards development.
Is your ASX-listed company doing something interesting? Contact: matt.birney@wanews.com.au
Is your ASX-listed company doing something interesting? Contact: matt.birney@businessnews.com.au
By Doug Bright
