• Energy Research

Abstract Under the Paris Agreement, nations of this world aim to limit temperature increase to well below 2 °C above pre-industrial levels and to pursue efforts to further limit the increase to 1.5 °C. Putting a price on CO2 emissions has been suggested as one approach to tackling global warming. This paper uses the results of suggested carbon pricing systems in the context of the Paris Agreement that consider biophysical boundary conditions for CO2 emissions. The impact of such carbon pricing is estimated statically for two ores – iron ore and bauxite – and four metals/ alloys – steel, aluminium, copper and gold – at a commodity level and a company level for some of the largest mining companies in the world. The authors conclude that at the commodity level the upper-bound impact of carbon pricing on metal prices would still be within the market driven price variations of recent years for copper and gold. The situation however looks different for steel and aluminium and for the companies, where prices and profitability would be significantly impacted, in some cases even by the minimum carbon prices used in this study, which would make mining unprofitable.

The heterogenous mineralogy of ultramafic deposits hosting mining operations makes it challenging to accurately determine the waste rock’s mineral carbonation potential (MCP). Additionally, the significantly higher carbonation capabilities of olivine than serpentine add to the difficulty. To address this issue, in this work, a new and unique tool called the MCP calculator was developed as a Microsoft ExcelTM spreadsheet to accurately determine the amount of anthropogenic CO2 that a given rock mass can sequester through mineral carbonation. The program estimates the modal mineral abundance of ultramafic rocks to aid in MCP estimation. This tool is designed to be cost-effective and tailored for use by the mining industry, utilising abundant lithogeochemical data to evaluate their deposit as a potential substrate for industrial mineral carbonation operations. The paper introduces the MCP calculator, outlines a framework for developing the MCP parameter, and presents an example of its application. The calculator is specific to the mineral assemblage investigated at the Turnagain ultramafic complex in northern British Columbia but can be adjusted to study comparable deposits. The paper acknowledges that using waste rock in a mineral carbonation operation requires economic and practical decisions beyond the scope of the research.

Carbon tax is an important economic instrument in achieving the goal of carbon emission reduction and sustainable development. This paper investigates the effects of carbon tax on carbon emission reduction in China. First, a non-competitive input–output table for Carbon Emissions of 28 sectors in China after Carbon Tax was established, based on the “2018 China Non-competitive Input–Output Table (42 Sectors)” and the carbon emission data of sectors provided by China Carbon Emission Accounts and Datasets (CEADs). Then, an input–output price model was established to study the changes on product price, GDP, employment, and carbon dioxide emissions of 28 sectors after carbon taxing ranged from 10 to 200. When the carbon tax rate reaches 200 yuan/ton, the inflation rate will be 5.907%, the total GDP will be decreased to 1.910%, the total labor force will be decreased to 1.744%, and the total carbon emission reduction rate will be increased to 8.171%. Results showed that with the increases in carbon tax, the inflation rate was increased, the rate of carbon emission reduction was increased, and the negative effects on GDP and employment were also increased. Suggestions on policy making, such as combination of carbon taxing and carbon trading, dynamic adjustment mechanism, tax neutrality, and forcing active carbon reduction, were proposed to minimize the adverse effect of levying carbon tax. The results from this paper would provide a reference for the policy making on carbon management.

Abstract This paper investigates the feasibility of mechanical activation as a pre-treatment method as part of an integrated mineral carbonation process for a nickel mining operation in British Columbia. The physical, structural and chemical characteristics of forsterite and lizardite in mine waste rock after mechanical activation were monitored to determine their CO 2 sequestration efficiency for a direct aqueous carbonation process. Economic analysis on the process was developed through considering the energy requirements, cost modeling and carbon balance. Mechanical activation on mining residue reduced the particle size, enlarged the surface area, distorted the crystal structure of forsterite, and enhanced the CO 2 sequestration efficiency. However, it didn't create new phase or induce phase transfer between forsterite and lizardite, and distort the crystal lattice of lizardite. The optimum condition for 60% CO 2 sequestration efficiency was found at mechanical activation for 210 kWh t −1 ore and carbonation for 260 kWh t −1 ore, which had an operating cost of 104.1–107.1 $ t −1 CO 2 avoided. Using mechanical activation, the integrated mineral carbonation plant in the mine can potentially sequester 14.62 Mt y −1 CO 2 using mine waste rock and tailings during the 28-year life of mine.

Proposed carbon reduction measures—such as cap-and-trade—appear poised to have a significant impact on the financial feasibility of mining operations as point-source emitters of carbon dioxide (CO2). It is therefore necessary to proactively assess the ways in which these effects may be mitigated. Carbon sequestration through mineral carbonation is well suited for integration into mining operations. Its ability to make use of waste rock to trap and store CO2, given suitable geological conditions, can help to significantly reduce carbon emissions. This paper presents the first attempt at conceptually integrating a high temperature and pressure industrial mineral carbonation facility into a developing minesite. The Turnagain nickel site, a low-grade, high-tonnage Ni-sulphide deposit, located in Northern BC, contains an abundant amount of Mg–silicate minerals in its waste rock. These minerals have significant potential for use in mineral carbonation. In the presence of a mandatory cap-and-trade scheme in North America, there is the potential to produce an additional revenue stream through the generation and sale of carbon credits. Results of financial modeling have yielded a net present value (NPV) at an 8% discount rate of $131.5 million for the integration of mineral carbonation into proposed mining operations at Turnagain, suggesting that the project may be viable from a financial standpoint. Sensitivity analysis has also demonstrated that the parameter with the greatest influence on project NPV is the CO2 avoidance ratio. This ratio, which takes into consideration the amount of CO2 released in the mineral carbonation process to determine the net amount of CO2 avoided, is critical to maximizing the amount of carbon credits available for sale in a cap-and-trade environment.

This study identifies the potential economic advantages and environmental/social aspects of three different scenarios for coal slurry pipelines as an alternative to current truck haulage system in ...

Ex situ aqueous mineral carbonation of ultramafic mining waste is an evolving technology for the CO2 sequestration from small- to medium-scale emitters. The mineral ores or mine wastes of associated ultramafic mineralogy are a suitable feedstock for mineral carbonation. The aqueous mineral carbonation at ambient temperature is motivating and attractive from an energy-saving perspective. This study has investigated the CO2 sequestration potential of a locally available ultramafic material generated from a nickel ore mine with a futuristic scope of integrating the method into an ongoing mineral extraction and/or tailing management operation. The mineral characterization and experimental results indicate that the tested material has CO2 sequestration potential and underwent carbonation at ambient temperature. The carbonate conversion efficiencies obtained for Ca and Mg from the dissolved ionic forms at optimum conditions are 60% and 25%, respectively. The material was able to sequestrate about 0.12 gCO2 per g solid at this efficiency. Aragonite and hydromagnesite are the major products that evolved out from the aqueous carbonation. Based on the mineral carbonation results, the novel concept of integrating the evolved method to existing mineral extraction and/or tailings management operation is discussed.

Abstract This paper evaluates the mechanical activation of mine waste (e.g. partially serpentinized olivine) using different milling machines, with a special focus on changes in microstructure and chemical transformation. The mechanical activation experiments were carried out using lab-scale high-energy planetary and vibratory mills, as well as a pilot-scale stirred mill, and laser diffraction, nitrogen adsorption, X-ray diffraction, and infrared spectroscopy were employed to identify mechanically-induced changes in the mine waste. Direct aqueous carbonation was used to identify the best type of mechanical activation for carbon storage in the mine waste. The experimental results demonstrate that agglomeration of the particles takes place during extended milling in dry conditions, and that there is an effective mechanical activation limit for crystallite size reduction during dry grinding; the higher the milling intensity, the smaller the forsterite's crystallite size will be at the mechanical activation limit. Additionally, stirred milling in wet conditions produces the largest specific surface area, and vibratory milling in dry conditions generates the most disordered materials. The serpentine content was slightly dehydrated during dry milling and was not activated at all during wet milling. The stirred mill proved to be the most efficient form of mechanical activation vis-a-vis the direct aqueous carbonation process, followed by the planetary mill and the vibratory mill, respectively.