Nickel Creek could be future carbon trap

Nickel Creek Platinum Corp. Dec. 16 announced results on the ongoing work toward carbon sequestering at the company's Wellgreen deposit on its flagship Nickel Shaw project in southwestern Yukon, Canada.

Under the guidance of University of British Columbia Professor Greg Dipple, Nickel Creek has been conducting experimentation at Wellgreen, a deposit with extensive nickel-copper-platinum group metals mineralization dominantly hosted in ultramafic rocks.

Aside from the veritable jackpot in critical materials toward electrification and decarbonization technologies, Nickel Creek approached Dipple to assess the potential for carbon capture and storage based on samples provided by the company.

More information on Dipple and his incredible work at Wellgreen can be read at CO2 absorbing potential of Wellgreen in the June 17, 2022 edition of North of 60 Mining News.

Basically, Dipple observed nearly two decades ago that ultramafic rocks, such as those that host the nickel-rich mineralization at Wellgreen, are among the largest carbon capture and storage reservoirs on Earth.

The carbon-absorbing potential of these igneous rocks with high magnesium and iron content, however, is limited when buried beneath tons of other particulates.

Thus, with mining activities unburying a particularly beneficial byproduct in the form of brucite – a highly CO2-reactive mineral form of magnesium hydroxide found in ultramafic rocks – adds a double-whammy to the already desperate need for the nickel, copper, and PGMs necessary to power a low-carbon future, the mining will necessitate CO2 reduction.

Mining and grinding of brucite-enriched ultramafic rocks to a sand-like consistency during the process of recovering the nickel, PGMs, and other metals maximizes the CO2 sequestering potential of these igneous rocks.

Over the last couple of years, Dipple has completed testing that indicates nickel projects in British Columbia, and now the Yukon, host enough brucite that the tailings and waste rock generated from mining has the potential to absorb large amounts of CO2 from the atmosphere – possibly more than is emitted by the mine.

Carbon-neutral nickel would be a prized commodity for lithium-ion battery and electric vehicle manufacturers that need large quantities of this battery metal. Lowering the CO2 footprint of materials going into the batteries powering EVs and storing intermittent green energy would offer an environmental, social, and governance advantage in the eyes of climate-conscientious consumers.

Now, with results coming in from the testing, Nickel Creek reports that initial results indicate a carbon sequestration capability of approximately 34.4 kilotons (million metric tons) of carbon dioxide per year (2.1 kt CO2 per metric ton of tailings).

The breakdown of brucite

Previous work at Dipple's CarbMinLab confirmed the presence of brucite in a subset of samples with concentrations ranging from one to 3% based on thermogravimetric analysis and leach tests.

The mineralogy and total inorganic carbon (TIC) content of the composite sample used in the current test work came out to roughly 0.6% brucite, 1.9% hydromagnesite, 88.3% serpentine, 6.9% magnetite, 2.2% chlorite, and 0.2% calcite – resulting in 9.6 grams of CO2 per kilogram TIC.

With this sample, the passive reactivity of brucite-bearing processed mine waste from the Wellgreen deposit was measured from influx of CO2 into solution and the increase in inorganic carbon from carbonate mineralization.

Essentially, a composite of Wellgreen pulps captured 2.1 g CO2/kg over 28 days.

First, a survey chamber was used to measure CO2 influx into the composite sample every four hours for two to three days. During this time, deionized water was added to account for evaporative losses daily, five days a week.

Furthermore, the composite was also churned to homogenize the material and bring the brucite to the surface five days a week.

After nearly a month of these steps, the experiment was completed, and the total inorganic carbon was measured on carbonated subsamples to asses the increase due to mineralized CO2.

Nickel Creek calculations approximate the generation of anywhere between nine to 16.4 metric tons of tailings generated per year.

On a mass basis, from the achieved numbers of the study, this would enable maximum sequestration of roughly 34.4 million metric tons of CO2 per year. While this is just a drop in the bucket compared to the estimated 36.3 gigatons of energy-related CO2 emissions emitted globally during 2021, it is only a matter of time before this technique and technology become mainstream.

And with the continued efforts by Dipple and colleagues, while it may be unique to specific geological regions, every success, no matter how small, should be appreciated toward the ultimate goal of climate healing.

You can read a more in-depth explanation of Dipple's company and work at Critical cobalt overshadowed by lithium and More low-carbon nickel the plea for 2022 in the Critical Minerals Alliances 2022 magazine published by Data Mine North.