Water is essential in most mining processes with responsible water use a critical issue for the mining industry. When excavating coal, metal ores, or other minerals, rocks and minerals that contain sulphur may be exposed to water and oxygen. This water holds highly polluting substances such as lead, zinc, iron, mercury, and cadmium. Acid or wastewater is often stored in a Tailings Storage Facility (TSF), as it has the potential to poison downstream waters and destroy already fragile ecosystems.

With the US National Oceanic and Atmospheric Administration (NOAA) forecasting a La Nina to continue in 2025, managing acid or wastewater on active and mine rehabilitation sites is more critical than ever.

More rainfall and flooding seriously threaten industries in the Southern Hemisphere that use water and tailings dams. If your dam or tailings facility is already close to its limits, prepare before the next heavy deluge hits. The 2025 TSF failure in Chambishi, Zambia, and the 2024 Jasgersfontein disaster in South Africa are reminders to effectively manage dams and TSF in operational and legacy mine remediation sites.

Conventional treatments of acid water include various physicochemical methods, which involve excessive use of chemicals and capital. Water evaporation has emerged as an efficient, cost-effective, and eco-friendly alternative for the remediation of abandoned or closed mines.

It’s estimated that over 32,000 tailings dams are located across operational and legacy mine sites worldwide. Organisations such as World Mine Tailings Failures call attention to the threats and risks of poorly managed and designed TSFs. Abandoned mines and TSF failures can leach harmful toxins into the soil and water, polluting the environment and posing a risk to human health. Fortunately, some steps can be taken to make mine rehabilitation and remediation sites safer.

What is mine remediation?

Mine remediation involves removing contaminants from tailings dams and repairing damage caused by mining operations. It is a crucial step in protecting the environment from mining’s harmful effects. Several different techniques can be used for mine remediation, including soil stabilization, revegetation, and decontamination.

Soil stabilization involves adding stabilizing agents to prevent wind and water erosion. Revegetation can be achieved by planting vegetation on mined land to help hold the soil in place and prevent erosion. Decontamination involves treating the contaminated soil with chemicals or other agents to remove contaminants. Mine remediation is a complex and expensive process, but it is essential for protecting the environment from the harmful effects of mining.

What is the difference between mine remediation and mine rehabilitation?

Two main approaches to dealing with abandoned mines are mine remediation and mine rehabilitation. Mine remediation is the process of making a site safe for human habitation or use. This typically involves removing hazardous materials, stabilizing structures, and capping mine shafts. On the other hand, Mine rehabilitation is restoring a site to its pre-mining condition.

What is mine rehabilitation?

Rehabilitation is a critical aspect in the life of mine.

Mine rehabilitation involves designing and building landforms and establishing sustainable ecosystems or alternative vegetation, depending on the desired post-operation use.

Before commencing any mining operation, companies work with government authorities to develop comprehensive rehabilitation plans. These plans decide the land’s post-mining use and include goals to return the resulting landform to a safe and stable condition.

The demand and push for sustainable mining practices has led to an increased focus on mine remediation in recent years. According to world market research, environmental remediation is forecasted to increase at a CAGR (compound annual growth rate) of 7.5%, estimated to reach $152 billion by 2025.

Mine remediation projects may include the following:

• Treatment or removal of soil, sediments, groundwater, or surface water
• The demolition and removal of unused infrastructure
• The upgrading of dams to protect against tailings spills
• Dewatering of tailings dams by evaporating contaminated water
• Engineered soil coverings for tailings ponds and waste rock piles
• Water treatment system upgrades to keep contaminated water out of the local watersheds

While effective and sustainable groundwater management of this toxic outflow is traditionally expensive, it is critical during any mineral processing application. Mining companies can treat or evaporate contaminated water to protect human health and the environment.

How can enhanced evaporation assist with mine remediation?

Enhanced water evaporation is a natural process that converts water from liquid to vapor. It can occur naturally in solar evaporation ponds; however, it is a slow process and requires a vast land mass. The cost of completing added storage ponds, along with the clean-up and revegetation, is often prohibitive.

Enhanced water evaporation is another approach to removing water from surfaces, dams, and tailing storage facilities. This helps to prevent corrosion or the dispersion of harmful metals and chemicals into the environment.

Minetek’s evaporation systems discharge water through a unique and patented water fracturing nozzle. This nozzle is engineered to achieve the correct water molecule size by fracturing to maximize performance via droplet reduction and direct water fragmentation. This water is injected into a high-volume/high-velocity air stream and propelled into the atmosphere, enhancing hang time and exposure to external ambient elements. Replenishing ambient air via a high-performance vane blower unit within the evaporator draws air from fresh ambient surroundings and achieves the highest possible evaporation.

Our evaporation units can process water with elevated levels of Total Dissolved Solids (TDS) and Total Suspended Solids (TSS) and a pH range as low as 1.8 and as high as 14. They offer a versatile and cost-effective solution to managing waste water.

What are the benefits of mechanical water evaporators?

Mechanical water evaporation units offer a range of benefits compared to solar evaporation ponds.

• This natural process does not require chemical pre-treatment
• It’s an efficient solution for removing surface water
• Supplies significant CAPEX savings
• No waste stream or operator is needed for use
• Rapid deployment of evaporation systems
• Minimal maintenance
• Not susceptible to changes in water feed quality
• Minimal footprint and power needed
• Mobile and robust evaporation systems, with a portable skid option.

Case Studies: Minetek’s Success in Mine Remediation

Minetek has a proven track record of delivering innovative water management solutions for mine remediation, helping clients achieve environmental compliance and operational efficiency. Our work with Knight Hawk Coal’s Viper Mine in Illinois, USA is a prime example. Facing the challenge of dewatering a 270-acre tailings storage facility (TSF) with 140 million gallons of high-pH wastewater, Viper Mine turned to Minetek for a cost-effective solution. Traditional water treatment methods, such as reverse osmosis, were prohibitively expensive due to the TSF’s high chloride (2000-2200 mg/l) and sulfate (3200-3500 mg/l) levels.

Minetek deployed two 200/100 Land-Based Water Evaporators, capable of processing 400 gallons per minute (GPM) at 145 PSI, achieving an evaporation rate of 30%. Over four months, the system reduced water levels by more than 2 feet, evaporating approximately 20 million gallons of wastewater. This enabled Viper Mine to progress toward its zero-discharge goal while avoiding costly chemical treatments. The evaporators’ mobile, skid-mounted design and ability to handle extreme pH levels (1.8 to 14) made them ideal for the project. Learn more about this success in our Viper Coal Mine case study.

FAQ: Mine Remediation and Enhanced Evaporation

1. How does enhanced evaporation compare to traditional methods?
Enhanced evaporation, like Minetek’s water evaporators, offers a cost-effective and eco-friendly alternative to traditional methods such as reverse osmosis or chemical treatments. Unlike chemical-based systems, enhanced evaporation requires no pre-treatment, reduces capital expenditure, and minimizes environmental impact by naturally converting wastewater to vapor. For example, at Viper Mine, Minetek’s evaporators processed 400 GPM without chemicals, achieving a 30% evaporation rate.

2. What types of water can Minetek’s evaporators process?
Minetek’s evaporators handle water with high Total Dissolved Solids (TDS), Total Suspended Solids (TSS), and extreme pH levels (1.8 to 14). This makes them ideal for tailings dams containing contaminants like chlorides, sulphates, or heavy metals, as demonstrated at Viper Mine.

3. How does evaporation support mine rehabilitation?
Evaporation reduces water volume in tailings storage facilities, enabling safer dewatering and reclamation. By lowering water levels, it prevents leaks, stabilizes dams, and supports revegetation efforts, aligning with sustainable mining practices.

4. Are Minetek’s evaporators suitable for all climates?
Yes, Minetek’s evaporators are designed for diverse climates, including humid continental regions like Illinois. Their high-velocity air stream and patented nozzle technology maximize evaporation efficiency, even in challenging conditions.

5. How quickly can Minetek’s evaporation systems be deployed?
Minetek’s mobile, skid-mounted evaporators enable rapid deployment with minimal setup time. They require no extensive infrastructure, making them ideal for urgent remediation projects.

Mine remediation is a critical process in sustainable mining practices. Minetek’s water evaporators offer a cost-effective and efficient solution for managing contaminated water. Discover how to save millions of dollars in water treatment costs, contact us below.