Innovation and Sustainability: Setting New Standards for Tailings Management

Though metals and minerals are essential for human progress, the process of mining them is harmful to the environment. The byproduct of mining – tailings – are toxic and their disposal must be managed correctly. Conventional tailings storage and management methods are risky and inadequate for their safe disposal. However, modern methods of tailings management can overcome the shortcomings of the current process and prove more feasible.

Metals and minerals have played a crucial role in human civilization. However, mining, processing, and using them have a severe effect on the environment and human health. Apart from large-scale excavation and release of toxic chemicals into the air, water, and soil, mining leaves behind a toxic byproduct known as tailings. The aftermath of their improper management could be fatal.

What are tailings?

The materials left behind after separating an ore's valuable fraction from the unprofitable fraction (gangue) are called tailings, which are in the form of very fine mud or powder. A ton of processed ore typically yields only a few ounces of metals or minerals. Hence, the quantity of tailings produced globally is quite large. The annual production of tailings worldwide was estimated to exceed 14 billion metric tons in 2022. Mining companies, governments, and environmental organizations must collaborate to find a smart solution to manage tailings.

Tailings management so far

The traditional method of disposing tailings is impoundment, which involves storing these in a diluted form in a built dam. Such storage is risky and an environmental hazard, especially if there is spillage. The tragic collapse of the Brumadinho tailings dam in Brazil in January 2019, which resulted in 270 fatalities and catastrophic environmental damage, is an example of tailings spillage. Furthermore, dams have limited storage capacity and require a huge amount of space and water, making tailings management an expensive undertaking.

While using this method, companies have to take numerous preventative measures to reduce risk, such as worker safety, preventing leakage into nearby ecosystems and waterways, and should be prepared for the possibility of a dam collapse.

The following are some efficient new-age technologies for tailings management:

• Sensory, Surveillance, and Filtration Technology (Storage and Recycling): Mining companies can set up a facility based on factors such as the composition of the tailings being stored, geotechnical concerns, precipitation and climate, seismic activity, community choice, and environmental safety. Some of the conditions are specific to every region, and the storage facility must be designed keeping those in mind. These modern facilities can be equipped with robust surveillance technology. Companies can employ thickening, filtration, pumping, conveying, and dry stacking techniques to process tailings. They can then process the produced water, metals, and minerals to facilitate recycling and reuse. The recycled metals, minerals, and water can be used by many other industries.
  In addition to robust surveillance technology, new-age facilities have regular staff inspections and annual audits to assess tailings facility performance, third-party audits, internal controls and governance audits, and an established independent tailings review board.
  
  
  • Columbia’s AuVert collaborated with CDE Group to deploy the latter’s dewatering and tailings management solution, which enabled AuVert to extract precious metals from tailings and 93% of the mercury from tailings land used by the local populace. Additionally, the water management system helped the company use only 23% of the water required compared to the traditional method. Of this, 90% of the water used by the system was recovered and ready for reuse.
  • At an Italian quarry, MB Crusher developed a method for fully utilizing waste and transforming it into a resource. On the quarry site in Lazio, one of MB Crusher's MB-S23 screening buckets was mounted to a Hitachi Zaxis 460 LCH to separate the waste material into two parts. The 0–100 mm fine material was sold for the construction of embankments. Excess rock aggregates larger than 100 mm were dumped into a dumper and fed into the processing cycle to be transformed into granulates for the construction industry.
• IoT, Automation, and AI: 
  About 19 storage failures could occur between 2018 to 2027 if industry practices and technologies do not evolve. There are several causes of tailings dam failure, but the most common one is overfilling or overtopping. Mining operators can use mobile IoT-enabled devices, networked sensors, satellite data, big data, and video feed from automated drones or fixed sites to continuously monitor a global network of tailings storage facilities. These data-driven insights improve a mining company's preventive maintenance procedures to control safety hazards and enable running an appropriate education and transparency campaign. This move would eventually eliminate human interference, saving money and time.  
  
  For instance, a trona ore mine faced issues with the effectiveness of its pumps and environmental compliance. Manual checks were the only way to check if the pumps were functional. The data received was also inaccurate sometimes. To overcome these problems, IWT Wireless deployed IWT Envko, a solution-oriented technology for environmental big data transmission and monitoring in inaccessible regions. It meshes radio nodes together to create a wireless network of connectivity that can transmit when line-of-sight networks cannot due to topography, vegetation, or other factors. The nodes determine the optimal path for data transmission without the use of infrastructure cabling. The solution enabled round-the-clock data monitoring, reduced costs and delays, and improved environmental compliance.

• Digitization:
  Digital solutions have enabled companies in the mining sector to tackle emission and waste management problems at scale. For example, Shell and IBM collaborated and launched a digital platform, Oren Solutions, which is an open platform that allows collaboration with different digital solutions in an end-to-end integrated manner. This solution was created after interviewing and gaining insights from 350 prominent mining players.
  
  Customers can use this solution to obtain data from sensors and other equipment, assess its quality, aggregate it, and carry out calculations. The mining business can leverage this knowledge to streamline processes, switch to renewable energy sources, and upgrade machinery with high carbon production.
  
  The tailings left behind after extracting and sorting precious elements from mines can be digitally managed using the tailings management tool.

• Geopolymer Technology: 
  Geopolymers are non-crystalline (amorphous), long-range covalently linked inorganic materials, usually ceramic. Tailings can be used as a precursor for polymerization to create geopolymers owing to their innate reactive silicon and aluminum content. Geopolymers made from tailings decrease volumes in storage facilities, eliminate associated risks, lower dam construction and monitoring costs, and facilitate a sustainable circular economy. Furthermore, these generate additional revenue for mine operators. For instance, Kiran Geopolymer produces geocement with the help of a geobinder made from fly ash, blast furnace slag, tailings, etc.

Way forward…

There is no single solution to the tailings management problem, but rather a combination of approaches. With the global trend skewed toward sustainability, investors are inclined to invest in green mining and tailings management technologies. Overall, the adoption of modern technologies for tailings management is a positive step toward responsible resource extraction. Companies must continue to prioritize these practices and try to reduce their environmental impact in order to build a more sustainable future.