TORONTO (miningweekly.com) – The preliminary results from pilot-scale flotation processing of ore from Quebec-focused project developer Canada Carbon’s Miller property have set a new ‘gold standard’ in graphite purity obtained from simple flotation processing.

The TSX-V-listed company last week reported that testing by consulting engineering firm SGS Canada, resulted in graphite with carbon purities greater than 99% for particle sizes larger than 200 mesh, potentially opening up certain high-value specialty markets, such as the nuclear or defence segments for the company’s product.

“We have achieved, with the simplest of processing methods, what could very well have set the new gold standard for the graphite industry,” executive chairperson and CEO Bruce Duncan told Mining Weekly Online in an interview.

The SGS pilot plant tests returned glow-discharge mass spectrometry (GDMS) results of 99.38% carbon for +200 mesh flakes, 99.52% carbon for +150 mesh flakes and 99.63% carbon for +100 mesh flakes.

Canadian research and technical consulting firm specialising in critical materials Stormcrow agreed with Duncan, saying in a report published on Thursday that, even at this stage with an unoptimised flow sheet, Canada Carbon was reaching at least battery-grade purities using nothing more than flotation.

The research firm compared the company’s latest results with that of rival TSX-V-listed firm Zenyatta Ventures and its Albany project, also located in Quebec.

Zenyatta early in September published results noting that their concentrates, after being subject to a caustic roast and leach process, had reached 99.95% purity, measured using GDMS.

Their concentrate achieved battery grade, being greater than 99.5% purity; however, fractions larger than +150 mesh produced by Canada Carbon reached at least battery-grade purity, with no additional chemical or thermal processing necessary.

“Needless to say, the cost for Canada Carbon to produce a high-purity graphite concentrate is likely significantly lower than the cost for Zenyatta to produce the same concentrate. This in no way implies that Zenyatta’s production is cost ineffective, but it does suggest that Canada Carbon may be able to produce such concentrates with a greater margin,” lead report author Dr Jon Hykawy said.

PROJECT DIFFERENTIATOR

Hykawy explained that the junior graphite sector was actually reasonably simple to understand, contrary to the opinion of most investors. For the most part, prospective producers of natural graphite would sell to the same markets and the same end-users as their larger counterparts. The most valuable graphite flakes were the largest and, with only small variation, the chemical purity of graphite extracted from a processing circuit would be very similar, somewhere between 94% and 98%.

The general rule of thumb was that the larger the fraction of flake produced from a natural graphite deposit and the lower the cost of production, the better the financial results that the company could generate.

It was also critical to note that, on average, any graphite deposit that was able to produce a flotation concentrate of 94% to 98% purity, would also be able to purify that graphite to a much higher degree and achieve at least battery grade.

While it might be difficult to license a conventional upgrading facility using hydrofluoric acid leaching, owing to the presence of highly corrosive and highly toxic hydrofluoric acid, there were several alternative processing methods available, including closed-loop hydrofluoric acid leach systems, caustic roasting circuits or simple high-temperature thermal treatments.

“But no conventional, disseminated natural graphite company is likely to be able to claim that their particular graphite is somehow special and somehow has a huge advantage over any other in terms of purification cost. What one company can do, others can,” Hykawy stated.

However, in the report, he stressed that Canada Carbon’s “startling” grades were produced with only a three-stage flotation circuit – a standard flow sheet for processing graphite – which had “shaken” Stormcrow’s perception of the junior graphite market.

Graphite ore containing less than 10% carbon was crushed, flash-floated to liberate the largest flakes, then repeatedly milled and floated to recover the usual proportions of flake. Bulk samples were collected from Miller, with assistance from SGS Lakefield, to gather a representative sample of run-of-mine material, as opposed to a collection of ore gathered by hand from potential veins.

“While Canada Carbon presently lacks a NI [National Instrument] 43-101 resource, we have visited the site and have seen a large selection of near-surface graphite veins spanning a significant land area. It seems unlikely that the resource size will be insufficient to establish a mine.

“It will be interesting to determine if the concentrates produced by Canada Carbon are easily expanded, or if the material may be able to be sold into certain high-value specialty markets. We have not previously seen graphite purity produced through flotation alone at anything like the levels produced by Canada Carbon and the implications for the cost of expandable and battery-grade graphite concentrates is very significant,” Hykawy said.

Stormcrow also noted that another potential cost advantage for the project was that a significant part of the Miller deposit appeared to be hosted in white, large-crystal marble, potentially enabling the mine’s host rock to be sold for a significant amount a tonne, further reducing the effective cost a tonne of Canada Carbon's graphite concentrates.

The Miller deposit is located about 80 km from Montreal, in Grenville Township, and has access to excellent infrastructure, including year-round road access and electricity.

Canada Carbon’s TSX-V-listed stock had gained 15% since the start of the year and on Thursday gained another 6.67% at C$0.24 apiece.