Weathering and cementation of historic kimberlite residues from South Africa: Implications for residue stabilization and CO sequestration.

Enhanced weathering and carbon dioxide (CO) mineralization of ultramafic mine wastes, including kimberlite residues from diamond mining, provides secure storage of this greenhouse gas and may physically stabilize mine impoundments. Yet, the outcomes of these processes over extensive periods (i.e.

The Mining Industry's Role in Enhanced Weathering and Mineralization for CO Removal.

Enhanced weathering and mineralization (EWM) aim to remove carbon dioxide (CO) from the atmosphere by accelerating the reaction of this greenhouse gas with alkaline minerals. This suite of geochemical negative emissions technologies has the potential to achieve CO removal rates of >1 gigatonne per year, yet will require gigatonnes of suitable rock. As a supplier of rock powder, the mining industry will be at the epicenter of the global implementation of EWM.

Environmental and Mineralogical Controls on Biosignature Preservation in Magnesium Carbonate Systems Analogous to Jezero Crater, Mars.

Jezero Crater on Mars is a paleolacustrine environment where Mg-carbonates may host evidence of ancient life. To elucidate the environmental and mineralogical controls on biosignature preservation, we examined samples from five terrestrial analogs: Lake Salda (Turkey), Lake Alchichica (Mexico), Qinghai-Tibetan Plateau (China), Mg-carbonate playas (British Columbia, Canada), and a mine with fine-grained ultramafic tailings (Yukon, Canada). The mineralogical compositions of the samples varied, yet were often dominated by either aragonite (CaCO) or hydromagnesite [Mg(CO)(OH)·4HO].

Microbially mediated carbon dioxide removal for sustainable mining.

The climate crisis and rising demand for critical minerals necessitate the development of novel carbon dioxide removal and ore processing technologies. Microbial processes can be harnessed to recover metals from and store carbon dioxide within mine tailings to transform the mining industry for a greener and more sustainable future.

Carbonation, Cementation, and Stabilization of Ultramafic Mine Tailings.

Tailings dam failures can cause devastation to the environment, loss of human life, and require expensive remediation. A promising approach for de-risking brucite-bearing ultramafic tailings is in situ cementation via carbon dioxide (CO) mineralization, which also sequesters this greenhouse gas within carbonate minerals. In cylindrical test experiments, brucite [Mg(OH)] carbonation was accelerated by coupling organic and inorganic carbon cycling.

Carbon Sequestration in Biogenic Magnesite and Other Magnesium Carbonate Minerals.

The stability and longevity of carbonate minerals make them an ideal sink for surplus atmospheric carbon dioxide. Biogenic magnesium carbonate mineral precipitation from the magnesium-rich tailings generated by many mining operations could offset net mining greenhouse gas emissions, while simultaneously giving value to mine waste products. In this investigation, cyanobacteria in a wetland bioreactor enabled the precipitation of magnesite (MgCO), hydromagnesite [Mg(CO)(OH)·4HO], and dypingite [Mg(CO)(OH)·5HO] from a synthetic wastewater comparable in chemistry to what is produced by acid leaching of ultramafic mine tailings.

Microbial and geochemical controls on waste rock weathering and drainage quality.

Bacteria can adversely affect the quality of drainage released from mine waste by catalyzing the oxidation of sulfide minerals and thereby accelerating the release of acidity and metals. However, the microbiological and geochemical controls on drainage quality from unsaturated and geochemically heterogeneous waste rock remain poorly understood. Here, we identified coexisting neutrophilic and acidophilic bacteria in different types of waste rock, indicating that robust endemic consortia are sustained within pore-scale microenvironments.

Accelerating Mineral Carbonation Using Carbonic Anhydrase.

Carbonic anhydrase (CA) enzymes have gained considerable attention for their potential use in carbon dioxide (CO2) capture technologies because they are able to catalyze rapidly the interconversion of aqueous CO2 and bicarbonate. However, there are challenges for widespread implementation including the need to develop mineralization process routes for permanent carbon storage. Mineral carbonation of highly reactive feedstocks may be limited by the supply rate of CO2.

Metagenomic analysis reveals that modern microbialites and polar microbial mats have similar taxonomic and functional potential.

Within the subarctic climate of Clinton Creek, Yukon, Canada, lies an abandoned and flooded open-pit asbestos mine that harbors rapidly growing microbialites. To understand their formation we completed a metagenomic community profile of the microbialites and their surrounding sediments. Assembled metagenomic data revealed that bacteria within the phylum Proteobacteria numerically dominated this system, although the relative abundances of taxa within the phylum varied among environments.

A greenhouse-scale photosynthetic microbial bioreactor for carbon sequestration in magnesium carbonate minerals.

A cyanobacteria dominated consortium collected from an alkaline wetland located near Atlin, British Columbia, Canada accelerated the precipitation of platy hydromagnesite [Mg5(CO3)4(OH)2·4H2O] in a linear flow-through experimental model wetland. The concentration of magnesium decreased rapidly within 2 m of the inflow point of the 10-m-long (∼1.5 m(2)) bioreactor.

Accelerated carbonation of brucite in mine tailings for carbon sequestration.

Atmospheric CO(2) is sequestered within ultramafic mine tailings via carbonation of Mg-bearing minerals. The rate of carbon sequestration at some mine sites appears to be limited by the rate of CO(2) supply. If carbonation of bulk tailings were accelerated, large mines may have the capacity to sequester millions of tonnes of CO(2) annually, offsetting mine emissions.

Microbially mediated mineral carbonation: roles of phototrophy and heterotrophy.

Ultramafic mine tailings from the Diavik Diamond Mine, Canada and the Mount Keith Nickel Mine, Western Australia are valuable feedstocks for sequestering CO₂ via mineral carbonation. In microcosm experiments, tailings were leached using various dilute acids to produce subsaline solutions at circumneutral pH that were inoculated with a phototrophic consortium that is able to induce carbonate precipitation. Geochemical modeling of the experimental solutions indicates that up to 2.

Subarctic weathering of mineral wastes provides a sink for atmospheric CO(2).

The mineral waste from some mines has the capacity to trap and store CO(2) within secondary carbonate minerals via the process of silicate weathering. Nesquehonite [MgCO(3)·3H(2)O] forms by weathering of Mg-silicate minerals in kimberlitic mine tailings at the Diavik Diamond Mine, Northwest Territories, Canada. Less abundant Na- and Ca-carbonate minerals precipitate from sewage treatment effluent deposited in the tailings storage facility.

Bioleaching of ultramafic tailings by acidithiobacillus spp. for CO2 sequestration.

Bioleaching experiments using various acid-generating substances, i.e., metal sulfides and elemental sulfur, were conducted to demonstrate the accelerated dissolution of chrysotile tailings collected from an asbestos mine near Clinton Creek, Yukon, Canada.

Biologically induced mineralization of dypingite by cyanobacteria from an alkaline wetland near Atlin, British Columbia, Canada.

Background: This study provides experimental evidence for biologically induced precipitation of magnesium carbonates, specifically dypingite (Mg5(CO3)4(OH)2.5H2O), by cyanobacteria from an alkaline wetland near Atlin, British Columbia. This wetland is part of a larger hydromagnesite (Mg5(CO3)4(OH)2.