Americas Tailings Inc. (ATI) is a Colorado-based, private, Earth-Friendly resource company focused on securing rights to develop historical tailings sites and, by applying modern, environmentally-friendly and commercially-viable processing technologies, to extract the metals value and remediate and/or repurpose tailings sites.

Proposal Summary

The Consortium comprising ATI and Advanced Materials Processing Inc. (AMPI) is proposing to repurpose fresh tailings by producing natural, bio-mineral, nutrient-rich fertilizer products from materials contained in the tailings using AMPI‘s patented technology.

The technology combines tailings rock feedstock with biomass material to produce a bio-mineral soil fertilizer (BioRoc) and a bio-mineral liquid fertilizer (RocTea), where elements typically considered deleterious or contaminants (N, P, K, Ca, Mg, Mn, Cu, Zn) are key ingredients for the nutrient-rich fertilizers. The fertilizer products would be transported and sold to the agricultural markets locally and overseas.

The Consortium has a repurposing project in New Mexico, where it is conducting development work supported by a federal Rural Business Development Grant (RBDG) from the US Department of Agriculture.

Solution

A modular-based processing facility would be developed to receive and process fresh tailings.

An initial slurry leaching stage using non-toxic solutions and catalysts is used to stabilize toxic elements, and produce an inert mineral agricultural product. A second stage bio-digestion process uses solid material from the initial stage as feedstock together with bio-waste (food waste). Liquid-solid separation produces an activated bio-mineral soil amendment and a liquid mineral fertilizer.

Auxilium Technologies Group LLC is a University of Arizona early-stage company headquartered in Tucson, Arizona, USA. It is a technology company whose primary focus is on tailings monitoring, processing, treatment and repurposing with a variety of novel proprietary technologies.

Proposal Summary

Auxilium offers a new proprietary solution called Entail™, which has several components that address the treatment and purification of water, extraction of ore content from tailings, energy generation, and the production of a unique tailings-based geofoam. This geofoam is a viable, sustainable solution for the construction industry. They aim to aid world emission goals by producing an innovative material that can be used as an insulator to decrease carbon footprint by reducing greenhouse gas emissions and providing energy savings.

Their process is ecologically sound and economically viable as it works on different types of base metals and is completely compatible with different processes.

Their value proposition will deliver three significant benefits; identify as many valuable products as possible and deliver a low-cost efficient solution while keeping the processes clean and sustainable. Having a holistic approach gives the opportunity to increment sources of revenue by taking advantage of industry needs and increasing outputs of value. From start to finish the processes are simple, easy to operate and scalable.

Solution

Entail™ comprises several integrated components used to create a complete solution for tailings repurposing  while producing several outputs of significant value. The complete system is comprised of new proprietary technologies. The process begins by producing various reagents using a novel bioreactor technology. Next, there is a metal extraction phase where the ore will be leached using one of their multiple extraction technologies. The effluent is later treated to precipitate leftover metal or rare earth content where water is then purified using a passive solar water purification system that can also generate hydrogen for energy storage. Finally, a geopolimerzation process is used to convert leftover tailings into a geofoam, which is a novel building material that can be used for underground mine.

The recomine-consortium formed in 2018 to develop holistic approaches for processing mining contaminations.  It pursues the objective of developing technologies for an exploitation of raw materials from mining waste under the leadership of the  Helmholtz Institute Freiberg for Resource Technology (HIF). Further members include the Technical University Bergakademie Freiberg; G.E.O.S mbH, a company specialized in engineering, (bio-)hydrometallurgy, and schwertmannite production; and the Sustainable Minerals Institute with its’ Centre of Excellence in Chile as a local partner that deals with civil engagement and leaching techniques.

Proposal Summary

The recomine consortium has put forward a comprehensive yet modular flowsheet that approaches the usage of tailings streams in a step -by -step fashion. The partner institutions involved in this proposal are leading experts in the resources sector and actively involved in research and innovation projects with global partners.

The flowsheet offers three modules: (I) processing of tailings to reduce the sulphide content, (II) processing of silicic residues and (III) water recovery. Many of these technologies selected are currently subject of innovation projects in the recomine consortium.

Solution

• Novel flotation techniques separate the remaining fine sulfide bearing particles from the silicate gangue. Depending on the material composition the recomine-proposal offers two options for further treatment of the sulfide concentrate. Option A is to leach the material for valuable metals. The Fe-rich leaching residue will be transformed into schwertmannite (SMT), which is an excellent metal sorbent for mine water treatment. Option B is to roast the sulfide concentrate using a suitable renewable energy source to generate iron (III) sulfate.

• The residues will be classified, de -slimed and separated from water by press filtration. The results are different grain size fractions of highly silicic material. Fine -grained clay materials find usage in construction materials as bricks and roof tiles. Intermediate or coarse -grained solid residues can be dry stacked or find usage in civil works at BHP or nearby construction sites. Coarse fractions may also be used in (geopolymer-) cements that find usage in basal layers or as top coatings of tailing heaps or in civil works.
• Reclaimed water undergoes processing. Novel membrane-technologies will raise efficiency in water treatment and support extracting valuable metals by further membrane or solvent extraction techniques. Non-selective techniques will filter residual contaminates and generate fresh water for reuse in BHP’s processes, in agriculture or as domestic water.

Minera Valle Central, the leader of the Cemtail Consortium aims to contribute to the social, economic and environmental sustainability of the mining industry, offering integral, sustainable and safe solutions to the problem of tailings. Its services include specialized consulting and operations advice, covering design of storage, processing, transportation and redepositation, engineering projects and water recovery. Other members are: Universidad Católica de la Santísima Concepción; INACAL, a subsidiary of Bio Bio Cements and; Schwager Service, specialist in maintenance, assembly and operation services for mining plants. 

Proposal Summary

The proposal is based on a mixed business model, seeking the overall profitability of the business from cross-subsidies between the following products to be marketed: minerals, mainly Copper and Molybdenum; water to be reinserted in mining processes; cementitious products that correspond to the incorporation of solid tailings in the manufacture of special cements and Cemtail, as a pelletized product for innovative applications.

Solution

Remine the tailings and produce Cemtail with the remaining material. The flowsheet includes Mineral extraction from tailings, extraction of granular material, water treatment, activation of tailings as a binding agent, production of Cemtail, abatement of dangerous substances, Cemtail Pelletizing. Additionally, research will be performed to develop dosages of Cemtail for different applications and for applying pellets to cementitious extrusion mixtures.

Pontificia Universidad Católica de Chile is a leading university in Chile offering top level educational and new knowledge to the society. With more than 30k students and 3.4k faculty members, the civil engineering group behind this proposal ranks internationally #32 according to QS, providing also applied research in association with multiple companies. Other members of the consortia are: DITUC, a research center; Melon, a leading cement company; Eral, an engineering firm; Paris Geopolymer Institute; and Noracid, a manufacturer of sulphuric acid.

Proposal Summary

The proposal aims to use the total of the tailings produced, leading to a Zero Waste Strategy plan using an innovative approach to merge the cleaning/extractive processes to recover Cu/Mo and sulfuric acid with the conversion/recycling processes to transform the tailing into construction materials. There will be an adaptive capacity of the technologies to “react” overtime to ensure a stable output against variations in tailings. The main innovation is the treatment of the materials to produce higher quality geopolymers and cementitious materials. The core, distinctive and innovative aspect of the Tailings to Construction Materials (T2CM-UC) proposal is the integration of technologies to transform the tailings into safe and sustainable construction materials. The proposal aims not only to add technologies, but also to adjust them to synchronize the overall performance of the system. The co-development of the technologies allows for maximizing the value of the processes. Some components of the proposal are developed, but others are original high-potential technologies developed by the team.

Solution

The first group of solutions addresses the tailings cleaning/extraction process via a multi-step strategy: MEL fresh tailings transport to a near or on-site treatment facility, fine grinding and particle size classification for surface activation and early sand and pozzolanic material production, rougher sulhide flotation to obtain a desulphurized material and a sulphur polymetallic concentrate, the sulphur- enriched material is separated in copper sulphide and pyrite fraction by flotation, the pyrite-enriched concentrate goes to a roasting step for sulphur removal and H2SO4 production, and finally the iron oxides desulphurized material is used to develop value-added construction materials.

Processed tailings will enter the conversion/recycling phase of the technology. These are divided in sieving of non-treated  materials for being used as a filler; geopolymeric aggregation of non-treated materials; geopolymeric aggregation of treated materials for high- performance materials; production of tailing-based cementitious materials, and bio-cemented materials.

The Solar Tailings Transformation (STT) consortium was created to develop a novel and sustainable solution to convert tailings material to valuable end-products through the application of solar thermal energy. It is led by the University of Queensland’s Sustainable Minerals Institute (SMI), a world-leading research institute committed to developing knowledge-based solutions to the sustainability challenges of the global resources industry, and its International Centre of Excellence, SMI-ICE-Chile. Other members include IMDEA Energy, a public non-profit research foundation that focuses its research on high-temperature solar concentration systems and technologies; and Seenso and Aiguasol Latam, specialists in renewable energy and energy efficient technologies.

Proposal Summary

The Consortium is developing a solution based on renewable energy to transform all the components of the tailings materials and recover the highest possible value. It can adapt to and take advantage of local context characteristics and generate flexible end products for multiple markets.

The solution is a two-stage solar-powered approach designed to: (i) recover a source of high-quality water, and (ii) transform the tailings into an inert, eco-friendly and easy to manage by-product. To maximize the sustainability of the solution, solar energy will be used as the primary energy source for each process.

The main benefits are: 1. The complete transformation and inertization of tailings material to avoid local contamination and socio-environmental impacts; 2.A readily available and low-cost material to support local industries; 3. Reduced pressure on local water resources; 4. An energy positive system that has the potential to increase energy availability; and 5. A zero waste approach.

Solution

The STT approach is comprised of two main stages which address specific issues that represent barriers to the beneficial reutilization of tailings.

The first stage addresses the high moisture content by drying the tailings through solar evaporation, while recovering high-quality water for other uses.

The second stage addresses the unstable nature of the dry material by agglomeration through partial melting at ultra-high temperatures and then sintering the agglomerates to produce physically and chemically stable pellets.

The final product will be an easy-to-handle granular material that will have value for diverse engineering applications in local markets.

The Solar Tailing Transformation concept is a sustainable approach that could lead to a paradigm shift in tailings management, taking a complex and difficult to handle mine waste and transforming it into an opportunity to support a more sustainable mining industry.

Mincore, the lead of the consortia is a medium-sized EPC enterprise. Focuses in processing, material handling and tailings management and has relevant experience in the retreatment of old tailings facilities. Other members include: BRGM (testing, metal recovery and tailings cleanup. France); VITO (testing, carbon capture and repurposing of tailings in construction material. Belgium); SoilCyclers (repurposing of tailings in soil for farming and/or construction. Australia); MEKS Solutions (project management. Australia); and Pacific People Solutions (international partnership, fund raising. Australia).

Proposal Summary

This consortium brings together Australian and European businesses with leading edge expertise in mining, tailings, water management, recycling, sustainability and circular economy solutions. The consortium is already involved in near zero mine tailings waste in Australia and Europe. This approach offers several innovative technologies to support the proposal that include:

• Innovative bioleaching reactor using floating agitators to mix and suspend solids in solutions as well as inject gases recovery into the pulp.
• Carbon capture and utilization technology to produce construction materials.
• Soil remediation for site rehabilitation, erosion controls or intensive agriculture.

In this way, tailings are treated as a resource to create saleable products, that can be marketed and sold, or utilized by BHP at the mine site.

Solution

Achieve a near zero mine tailings waste flowsheet based on economic principle intended to provide additional income. Tailings are reviewed as part of a resource and become an important by-product and asset to be processed and marketed.

The process involves an integrated five stage recycling process: (i) Extracting the remaining minerals and decontamination (BRGM); (ii) Dewatering, classification and sorting (Mincore & MEKS Solutions); (iii) Capturing CO2 in minerals later repurposed in raw material (VITO); (iv) Production of construction materials (VITO), and;(v) Transformation of the remaining tailings into organic soil suitable for rehabilitation and creation of a new agriculture industry (SoilCyclers).

The University of Valparaíso (UV) is a state, regional and autonomous institution with a total of 17,509 students and 1,865 academics. The team also includes researchers from Universidad de Cadiz, Spain and Universidad Nacional de la Plata, Argentina.

Proposal Summary

The proposed solution is divided into three main lines: (i) production of green hydrogen catalyzed by metal oxides present in the tailings; (ii) stabilization of metals present in the insoluble fraction of tailings; and (iii) the incorporation of the residual insoluble fraction as the main constituent in the production of mineral paper. This approach is highly innovative and no evidence has been found in the literature of its application in an integrated manner as a global solution applicable to the transformation of tailings to obtain marketable products.

Solution

Three production lines:

• Hydrogen: Solar powered thermochemical water splitting cycles (TWSC) are a promising, high-efficiency avenue for hydrogen production from water and solar energy, abundant and clean resources (Charvin et al., 2007).The thermochemical cycles of water division are based on the decomposition of water through repetitive series of chemical reactions that use intermediate reactions and substances that are recycled during the process, so that the general reactions are equivalent to the dissociation of the molecule of water into hydrogen and oxygen.
• Bioprocess for sulfuric acid production: In a first stage, and by means of a bioleaching process that uses S and Fe (for example from pyrite) it is possible to oxidize sulfides to sulfates, releasing protons that allow obtaining a liquid phase with sulfuric acid and whose pH allows the solubilization of heavy metals. These can be recovered from sulphide ores by the action of iron (II) – and sulfur oxidizing microorganisms, whose fundamental action is the continuous generation of an oxidant (ferric ion) that provokes the dissolution of metal sulphides.
• Mineral paper: This product (Stone paper), compared to cellulose paper, has the advantage of having a lower water footprint, an average reduction in associated CO2 emissions of close to 900 kg per ton produced, among others. In the formulation of the mineral paper, a binder polymer must be used that has characteristics consistent with the environmental sustainability of the product. In this sense, it is possible to use biopolymers (PHB, PLA, etc.) to fulfill this function. The traditional mineral paper production technology is in TRL 9.

The University of New South Wales (UNSW) is a leading education and research-intensive university, delivering outstanding teaching, cutting-edge research, and industry partnership. One of the World’s top 100 universities, UNSW has a proud tradition of breakthrough technologies. Its research assists industry, government, and community and informs policy on key issues facing society. The consortia include Mets Ignited, Golder Associates, Maptek, Roobuck, Xilink, HNTB Corporation, and STMicroelectrconics.

Proposal Summary

UNSW’s industry and research consortium provide a Systems Engineering Approach with circular economy and digital twin frameworks to deliver an integrated and agile business solution to the global tailings challenge. This approach is an industry first, providing: adaptability and interoperability between different sites; business agility; modular design to integrate and adapt different technologies; predictive modelling and optimal control via digital twins and data analytics. Its novelty is converting waste to assets. The consortia have the collective capability to translate research outcomes firstly into prototypes and then to scaled industrial solutions.

Solution

UNSW’s consortium has designed an integrated engineering, business, and environmental framework for tailings management. This can be achieved by incorporating a circular economy approach of tailings materials by reprocessing wastes into valuable by-products and repurposing non-valuable tailings as backfill materials to help stabilize underground workings. This unique merger of real-world and digital-world tailings management relies on multi-disciplinary capabilities of the team, providing essential components for the full integration of new knowledge and technology to achieve operational excellence. The integrated system will monitor and manage tailings asset infrastructure via a digital twin to optimize materials and water extraction, and energy and water usage according to sustainable, socially acceptable, market and risk-driven frameworks.

For managing the fraction of future tailings that may not be repurposed, the solution implements a risk management strategy. This combines state-of-the-art geophysical monitoring, weather forecasting, economic and risk modelling, multi-physics, and multi-scale simulation techniques based on material characterisation workflows in conjunction with data science and analytics. This will be applied to accurately map the internal structure of the newly deposited tailings, examine mechanical stability and integrity, and feedback online information from sensors to a physics-based modelling framework, during 10,000-year design life.

UNSW has a number of technologies in development to achieve the above outcomes. Phase 1 will focus on assessing potential tailings volume reduction. The technologies that will be used in Phase 1 include NovaCell^TM, Dissolved Air Flotation (DAF) unit, and supercritical CO₂ leaching. In Phases 2 and 3, the above-mentioned technologies will be further scaled up and digital twin, including its supporting structures, will be developed.