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Lightspeed answer to backlogged assays

North of 60 Mining News - November 4, 2022

PhotonAssay tech offers a modern, faster alternative to fire assaying for gold analysis.

Assays are the very crux of mineral exploration – timely results returned from the lab help guide the search for orebodies and let investors know that the dollars being poured into drilling and sampling is money well spent.

With assay lab turnaround times in a post-COVID world being measured in months instead of weeks, mineral exploration geologists are without an important tool for vectoring the next drill holes, and financiers tighten purse strings until they have quantitative evidence that their investments could yield the next big discovery.

Across Alaska and Northern Canada, this chain of delays is exacerbated by an exploration season that is barely longer than post-pandemic assay turnaround times.

"Instead of using geochemical results from a June drilling program in Alaska to guide what is done in the next few months and help formulate next year's work program and budget, the industry is now waiting half a year or more to get results. And this means working geochemically blind for the entire Alaskan field season. But it also means that analyzing field results and settling on budgets were drastically delayed until early in the next year," Avalon Development President Curt Freemen penned in a July editorial.

Slow assay turnaround times are not new to North of 60 mineral explorers – every few years there is a surge in exploration that assay labs are slow to respond to, causing a backlog of samples. The assay lab backlogs over the past two years, however, are at historical proportions due to post-COVID labor shortages and tangled supply chains.

This has mining, mineral exploration, and analytical companies all looking for answers to this age-old problem.

One such solution is PhotonAssay, a mineral sample analysis technology that came on the scene in Australia in 2016 and is gaining popularity as an almost purpose-fit solution to the current assay backlog problem.

Faster, simpler, and less labor-intensive than the traditional fire assay that has long been the standard for determining how much gold is in a sample, PhotonAssay has the potential to revolutionize the analysis of precious and other metals.

"The technology's fast turnaround on high sample volumes provides customers with time-critical operational data and drives optimization through their entire value chain," said Dirk Treasure, CEO of Chrysos Corp., the company commercializing PhotonAssay.

After 5,000 years

Considering that the first results from fire assay were scribed on clay tablets nearly 5,000 years ago, PhotonAssay has a lot to prove when it comes to measuring up against the time-tested method of analyzing quantities and purities of gold, silver, copper, and other metals.

The basic process of fire assaying to determine how much gold or silver a sample contains has not really changed much since the days of the Old Testament – samples are crushed, mixed with fluxing agents, heated in a furnace until the metals become molten and separate, and then the targeted commodity is weighed.

While time-tested, this process takes around three to four hours to complete and is dependent on the experience of the assayer for accuracy.

"The key to an accurate assay is the skill and experience of the staff who are able to balance all the factors which may contribute to any variations," according to Sheffield Assay Office, which has been carrying out precious metal assays in England since 1772.

While PhotonAssay may take away from some of the deep-seated nostalgia that comes with using flames to reduce a sample to a metal bead that is weighed for its content, this new assaying technology vastly reduces the time and chance for human error.

Instead of prepping a sample with fluxes and other additives in preparation for the furnace, crushed samples to be analyzed by PhotonAssay are simply put into uniquely identified containers that are weighed and then placed on a conveyor belt to be fed through the analysis machine.

With an accurate measurement of the contained gold in as little as two minutes, a single PhotonAssay unit can process up to 1,400 samples per day, with only a single operator needed to place samples on the input conveyor and remove analyzed samples from the output side.

"Our PhotonAssay installations provide single-touch operation and improved safety outcomes, whilst also reducing labor requirements and the potential for human error," said Treasure.

PhotonAssay is born

A product of Australia's Commonwealth Scientific and Industrial Research Organisation (CSIRO), PhotonAssay works on the same basic premise as the handheld XRF (X-ray fluorescence) analyzers that have become an important tool for getting a first read of rock content while in the field.

Samples fed into a PhotonAssay unit are bombarded with high-energy X-rays that excite the atomic nuclei of the contained gold; signature gamma rays emitted by the excited aurum are measured, quickly providing a highly accurate analysis of the gold contained in the sample.

This allows operating mines with a PhotonAssay unit on-site to monitor grade in real-time and allows mineral assay labs to more easily keep up with the annual surge in samples that come from northern exploration programs that typically run from June to October.

In addition to speed, PhotonAssay units can analyze sample sizes ranging from 250 to 650 grams, compared to the 10- to 50-gram sample size with fire assay. These much larger samples provide a more accurate analysis of high-grade gold systems where assay results can be skewed by the nugget effect – depending on whether an outsized lump of gold was either included or excluded from the sample.

"This award-winning technology is capable of rapidly and accurately scanning up to 500 grams of materials at a time, an important capability when dealing with coarse gold systems," according to Novo Resources Corp., one of the early adopters of PhotonAssay for gold exploration sample analysis.

PhotonAssay machines can also be tuned to detect for silver, copper, and other complementary elements.

Testing has shown that this new analysis technology to be highly accurate, and PhotonAssay units are operating in National Association of Testing Authorities laboratories in Australia, and PhotonAssay results are included in numerous resource calculations that are compliant to Australian Joint Ore Reserves Committee- (JORC) and Canadian NI 43-101 standards.

Adding to the simplicity, speed, and accuracy, another major advantage PhotonAssay has over fire is it does not destroy the sample, making it available for future metallurgical testing and other analysis.

At Aussie assay labs

The first two commercial Chrysos PhotonAssay units were installed at MinAnalytical's lab in Perth in 2018 and 2019. By the end of 2021, the Australian analytics company had installed a third unit and was bought out by rival ALS Ltd., which was looking to add PhotonAssay technology to its offerings.

"This is a strategic bolt-on acquisition for our geochemistry business, which further expands our capacity and technological service offering to our clients," said ALS CEO Raj Naran. "It supports our strategy to grow mine site testing which delivers more stable sample volume throughout the commodities cycle."

The biggest endorsement of PhotonAssay was from Intertek, a United Kingdom-based global leader in quality assurance.

In 2021, Intertek ordered two PhotonAssay units for installation at its new Minerals Global Centre of Excellence – a state-of-the-art laboratory that consolidates Intertek's minerals operations into a single 20,000-square-meter (215,300 square feet) building with more than 500 employees.

Having the PhotonAssay units in place at the opening helps to ensure the facility delivers cutting-edge precious metals assay technology to its mining and mineral exploration clients.

"Intertek continually evaluates new innovations to deliver customer value. In that vein, we feel our partnership with Chrysos is more than a simple investment in faster, cleaner operations; we see it as a social and environmental commitment to our customers and the broader global industry," said Intertek Senior Vice President of Minerals, Exploration and Production John Fowler.

Australian gold miner Novo Resources wasted no time in signing a multi-year deal for priority access to the PhotonAssay units installed at Intertek's Centre of Excellence. One reason for making a quick leap to ensure it is at the front of the line is the belief that PhotonAssay is the ideal technique for analyzing the nuggety gold-bearing conglomerates at its Beatons Creek paleoplacer project in Western Australia.

"Accurate assaying for coarse gold has always been a challenge, and it's on difficult deposits where the much larger sample mass of PhotonAssay really delivers," said Chrysos Chief Technology Officer James Tickner. "It's great to see industry recognizing this, with Novo Resources committing to run at least 20,000 samples per month through each unit at Intertek's brand-new facility in Perth. The two PhotonAssay units we've just commissioned there will really help Intertek deliver faster, cleaner, and more accurate results, not just for Novo, but its other customers as well."

Going into 2022, three of the four largest global assay companies – ALS, Intertek, and SGS – had PhotonAssay units installed at their labs in Australia.

Global installations

British Columbia-based MSALABS, a global provider of geochemical laboratory services for the exploration and mining sectors, was the first mineral analytics company to take the 5,000-year leap from fire to PhotonAssay beyond Australia.

"Adding Chrysos PhotonAssay into the mix of our offering for our global mining customers is exciting for us," MSALABS CEO Stuart Thomson, CEO of MSALABS said in mid-2021, when MSALABS placed its first order for six units to be installed at mining operations and labs in Africa and Canada.

The company's original rollout of this 21st-century assaying tech kicked off with the installation of a PhotonAssay machine at Barrick Gold Corp.'s Bulyanhulu gold mine in Tanzania, the first such unit outside of Australia.

"This technology will significantly improve the turn-around-time of analysis results for Barrick, providing consistent delivery of critical data within timeframes not possible with fire assay," the MSALABS said upon the October commissioning of the PhotonAssay unit at Bulyanhulu. "Furthermore, it will significantly improve employee safety and environmental outcomes at the lab."

MSALABS has also installed PhotonAssay units in Mali, Africa, and Quebec, Canada. Another three units are slated for installation in Cote d'Ivoire, West Africa; the Democratic Republic of Congo; and Ontario, Canada, by the end of the year.

At an opportune time

With restricted travel, snarled supply chains, labor shortages, and other post-pandemic hurdles, the introduction of PhotonAssay could not have come at a more opportune time.

"Over the past year, we have seen very strong demand for Chrysos PhotonAssay, and we expect this interest to continue to grow as our global mining customers not only gain confidence in its accuracy and reliability, but also benefit from the substantially improved turnaround time for results not possible with fire assay," Thomson said earlier this year.

With growing demand for the faster turnaround times offered by this revolutionary gold analysis technology, MSALABS has ordered an additional 15 Chrysos PhotonAssay units for installation over the next two years.

The Canada-based assay company says it is currently engaged with multiple mining companies, including most of the top 10, that are interested in PhotonAssay installations.

According to Chrysos, due diligence for the installation of PhotonAssay units by MSALABS and others is being carried out for 36 locations around the globe, including 10 in North America.

Alaska, Alberta, British Columbia, Manitoba, Mexico, Nevada, Nunavut, Ontario, Puerto Rico, and Yukon are the North American locales under consideration.

BC-based MSALABS, which currently operates 18 laboratories on four continents, is anticipating substantial revenue growth from being among the earliest adopters of PhotonAssay technology.

"The PhotonAssay technology is expected to disrupt the industry and has the potential to change the way the exploration sector operates globally," said Thomson.

A disruption that would be welcome to gold mining and mineral exploration companies that are waiting on assays across Alaska and Canada's North.

Author Bio

Shane Lasley, Publisher

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Over his more than 16 years of covering mining and mineral exploration, Shane has become renowned for his ability to report on the sector in a way that is technically sound enough to inform industry insiders while being easy to understand by a wider audience.


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