Canada Nickel Demonstrates Carbon Sequestration Potential of Tailings from Crawford Project
Canada Nickel Company Inc. is reporting the results of the first phase laboratory scale testing, which demonstrates the potential for carbon sequestration in tailings at its Crawford Nickel-Sulphide Project near Timmins.
The laboratory tests were conducted by researchers from Kingston Process Metallurgy and Queen’s University and demonstrate that the project tailings naturally sequester CO2 into a mineralized form, which industry research has demonstrated is permanent. This is a critical foundation of Canada Nickel’s NetZero initiative to become the first zero carbon nickel operation. Canada Nickel’s wholly-owned Net Zero Metals subsidiary has successfully applied and registered trademarks in various jurisdictions for NetZero Nickel™, NetZero Cobalt™ and NetZero Iron™ in expectation that the Company believes it can be successful in achieving its zero carbon initiatives.
Mark Selby, Chair and CEO of Canada Nickel commented, “Today’s announcement is a critical demonstration that our tailings have the fundamental capacity to capture CO2 in amounts that exceed what we believe will be required to achieve net zero carbon production for our concentrates. Any CO2 sequestration in excess of the 4.6 kg per tonne of tailings level would be potentially available for sale as carbon credits. Work is underway on a series of larger scale tests aimed at demonstrating that Crawford tailings can be exposed to enough CO2 for a sufficient time period to achieve the sequestrations levels that were achieved at a lab scale. We look forward to seeing the results over the coming year.”
What is mineral carbonation
The tailings and waste rock produced from the Company’s Crawford Nickel-Sulphide Project are anticipated to spontaneously and permanently capture CO2 when exposed to the atmosphere. Canada Nickel is developing processes to optimize the carbon capture potential of the Project to offset project emissions and work towards developing a potentially carbon negative nickel mining operation in Timmins, Ontario.
The key minerals that are responsible for this spontaneous reaction at Crawford are serpentine, olivine and brucite, which make up more than 80% of the resource material at Crawford. Brucite is the most reactive mineral, with an average content of 1.9% in Crawford based on 999 distinct QEMSCAN mineralogy analyses across the Crawford Main and East Zones as reported in the Preliminary Economic Assessment (“PEA”) dated May 25, 2021. Based on the brucite concentration above, it is estimated that only 31% of the brucite in Crawford needs to be carbonated to offset all of the estimated emissions from the PEA to make the operation carbon neutral.
Evidence of mineral carbonation can be seen on the surface of drill core over time. Figure 1 shows drill core taken from Canada Nickel’s Crawford Project after one year of storage. The surface of the drill core has turned white due to carbonation recations with atmospheric CO2.
Description of Current Results
Based on analysis by Skarn Associates, Canada Nickel estimates a preliminary emission intensity of 2.8 tonnes CO2 / tonne of Nickel equivalent concentrate production using data from the Crawford PEA. In order to offset all of the estimated Scope 1 and 2 emissions from the proposed mine and mill, the Company estimates that a carbon capture rate of 4.6 Kg CO2 per tonne of tailings produced is required. Figure 2 shows that a sample of Crawford tailings are surpassing this capture rate in the upper tailings layer after approximately 14 days. At 112 days, the top layer has achieved carbon capture of 17.5 kg CO2 per tonne of tailings and the carbon capture rate of the entire column has nearly surpassed the 4.6 kg CO2 per tonne threshold. This highlights the carbon capture potential of the Crawford tailings, the potential for the generation of carbon credits, as well as the importance of tailings deposition for optimized mineral carbonation. The next stage of test work will evaluate on a larger scale sample how much of this potential can be realized.
These results are the product of experimental work that was completed at Queen’s University to measure the effect of time and tailings deposition depth on the progress of mineral carbonation reactions using tailings produced from Canada Nickel’s metallurgical test program. Figure 3 outlines the experimental set up that was used for this first set of tests, as well as the amount of carbon captured for each layer of tailings within the column with no active effort to accelerate the rate of mineral carbonation.
This first column cell test, which was completed on a sample with typical brucite concentration and with no active effort to accelerate the reactions, show a maximum carbon sequestration rate of 17.5 Kg CO2 /tonne of tailings in the upper 1 cm layer of tailings, an average carbonation rate of 9.2 Kg CO2 /tonne of tailings in the upper 4 centimetres of the column and an average of 4.2 Kg CO2 /tonne of tailings throughout the entire column after 112 days in laboratory setting. Mineral carbonation reactions decrease with depth in the experimental cell because there is less CO2 transported to the mineral reaction site. Canada Nickel is developing strategies to inject CO2 laden off-gases into the tailings storage facility as well as other opportunities, to increase the supply of CO2 to the mineral site and in turn the carbon capture of the tailings.
Figure 3. Carbon Capture Rate according to depth in column cell tests after 112 days
Description of Current Test Program
Canada Nickel is working with Kingston Process Metallurgy and Queen’s University to optimize the carbon sequestration potential of waste rock and tailings that will be potentially produced from Crawford. Our approach to optimizing the mineral carbonation potential of the project is to complete techno-economic evaluations of various strategies to accelerate mineral carbonation and pursue the options that are thought to be viable from a capital and operating cost perspective at current carbon prices. Our integrated academic-industrial team has identified a number of opportunities to accelerate the mineral carbonation reactions which will be tested in two stages of pilot studies starting in 2022.
In addition to the experimental work that is being completed, Canada Nickel is conducting an aggressive mineralogy program to map out the key economic minerals of the deposit and understand the areas of the deposit that have the highest potential for carbon sequestration. To date, more than 1500 distinct samples have been characterized mineralogically across the breadth of Crawford. The mineralogy results will eventually be incorporated into the block model so that the carbon sequestration potential of extracted material can be incorporated into the mine schedule.
Description of Future Test Program
Canada Nickel is planning two larger scale pilot tests to continue to evaluate the carbon sequestration potential of tailings produced from the company’s metallurgical test program, as well as to test various strategies for accelerated mineral carbonation. Pilot scale testing will be completed in two phases starting in the first quarter of 2022, with a tote test loaded with 1-tonne of tailings and then followed by an approximately 25 tonne test starting in the second half of 2022, which will be completed in a dynamic, outdoor environment in Timmins, Ontario near to the project site. Canada Nickel has already started the design of the 1-tonne tote test and has produced the tailings required for this. The 25-tonne pilot test will require a mineral processing pilot plant to generate the tailings which provides the additional opportunity to demonstrate the metallurgical flowsheet at scale and generate bulk concentrate for testing in flowsheet development efforts aimed at the downstream processes. The larger scale pilot test is being planned for the second half of 2022.
Tags: Northern Ontario / Processing / Battery Metals / All Articles