Controlling airborne dust in underground and open pit mines is one of the most difficult tasks for mine operators in places like Chile, Canada and Peru. Dust controlling measures are often taken into consideration by above-ground mining teams as the dust is visible and noticeable. Underground mining activities, on the other hand, are sometimes forgotten and neglected but it is in these mines that fungal dust and health issues occur.
In this article, we look at some of the most common sources of dust in underground and open pit mines, as well as some of the most effective dust control strategies.
What are the main sources of dust in mining?
The main sources of emissions in underground and open pit mining are caused by the following activities, in order of relevance:
- Loading, transporting and unloading of materials and minerals: More than 50% of the dust in mines is generated by blasting, loading of the materials on the loading fronts, their subsequent transport on haulage roads or tunnels, and unloading in primary crushers or landfills. The emission sources in these activities are mainly associated with the discharge of materials and the erosion generated by truck wheels on unpaved roads. Blasting is a significant but not continuous source of dust, which is programmed to avoid the presence of personnel in the vicinity and to apply the respective suppression and control measures.
- Crushing and screening of minerals: The primary, secondary and tertiary crushing processes and their respective screening generate a high amount of PM10 and PM 2.5, generating an ultra-fine powder with high volatility. This dust, in addition to being highly harmful to health, generates fire hazards in the pulleys of the conveyor belts, and penetrates all equipment, accelerating their wear. The emission sources in these activities come from the process of reducing the granulometry of the material, passing it through different screens, belts and chutes.
- Stockpiles and tailings dams: Stockpiles and tailings dams usually contain very fine material, and are highly sensitive to wind erosion.
ABCDust offers comprehensive dust modeling, suppression and monitoring services throughout the different activities of the mining process. If you would like to discuss a tailor-made solution, please contact us.
What is the difference in dust control in underground mining and open pit mining?
In open pit mining, extreme dust concentrations are largely diluted by atmospheric dispersion and winds, thereby mitigating the level of exposure for workers to some extent. However, the wind carries PM10-2.5 pollution to the surrounding communities and the environment around the mine, which is why it is important to take efficient and effective measures for its control and mitigation. Likewise, during the day environmental conditions of low dispersion of dust tend to generate extremely high concentrations in the operation, which translates into visibility problems, and negative impacts on the health of workers.
In underground mining, dust and gas concentrations are usually very high as they are concentrated in tunnels and underground galleries, generating a high risk for mine operators. In addition to dust, due to the high temperatures of 30 – 40 °C in underground tunnels, mold and fungi are generated which increase the risks of respiratory diseases for operators. That is why, in underground works, dust, temperature, gases and molds are monitored and mitigated through the implementation of ventilation systems, filters and air quality monitoring.
How do you control dust in mines?
Hierarchy of Controls
The hierarchy of controls shown below is helpful to reduce the danger of workers being exposed to harmful dust particles. Higher-order controls (e.gelimination, substitution, and isolation of the hazard) should be prioritized as the most effective means of treating the hazard.
The following is the order in which hazard controls should be implemented:
- Elimination — Remove the hazard or the requirement to engage in the harmful activity.
- Substitution — Substitute a safer option for the original.
- Separation/isolation — use barriers, distance, or time to isolate or separate people from the hazard.
- Engineering — Redesign or modify tools or equipment using engineering controls.
- Administrative Control — To limit the danger of a hazard, apply administrative controls such as training, rules, and procedures.
- Personal protection equipment — make sure you have the right gear for the job.
These measures must be modeled beforehand. In the mine design phase, equipment and infrastructure, dust emissions and suppression measures are modeled, in such a way as to prevent problems and program the respective suppression measures.
Later, during implementation, more than one control may be required. To ensure that the applied controls remain effective, they must be monitored, evaluated, improved and maintained.
Examples of Dust controls
- Adopt industrial methods that produce less dust (any wet method is likely to generate less dust than a dry one).
- It is more effective to treat the dust where it is generated rather than capture it in the air.
- Dust suppression techniques (e.g., water sprays, chemical additives, local exhaust ventilation (LEV), vacuum) can be used to treat dust on its transmission course.
- Replace with a less dangerous product, such as pellets instead of powders, or garnet instead of sand as an abrasive blasting agent.
- Create a physical barrier between the dust-producing task and the worker, for as by isolating workers in enclosed cabins.
- Use machinery that can be controlled remotely, such as conveyors.
- Select the proper equipment (e.g. correct cutting blades for the ore body).
- Cutting blades and picks should be replaced and maintained on a regular basis to ensure they remain sharp.
- Dust can be reduced by spraying water droplets on stockpiles and highways, as well as when using machinery and cutting equipment. To suppress dust, add an ingredient to water sprays and tune the droplet size of the spray to the size of the dust particle.
- Make use of enclosures
- Rehabilitate exposed mining land to lessen the amount of dust in the environment.
- To reduce dust, employ ventilation and filtering (e.g., modify ventilation rates for maximum effectiveness and use local exhaust ventilation as needed).
- Ensure that trucks and mine workings are maintained and cleaned on a regular basis.
- Establish exclusion zones to keep personnel away from dust-producing activities.
- Maintain unpaved roads and ensure that the ground conditions on all sites are suitable for the machines that will be using them.
- Provide workers with training and information about the hazards, risks, and controls associated with dusty tasks, as well as worker supervision.
- Limit the amount of time and amount of dust you are exposed to (e.g. worker rotation, job task changes).
- Before using PPE, make sure that higher-order controls are in place.
- Choose the most suitable breathing protection for the job.
- Before using, ensure that training, comfort, and fit testing are provided. It’s not a good idea to share your respirator.
- Respiratory protection equipment should be properly maintained and stored.
ABCDust has a team of professionals to help you implement these dust modeling, suppression and monitoring measures throughout the different activities of the mining process. If you would like to discuss a tailor-made solution, please contact us.
Why is dust control important in the mining industry?
Long-term exposure to dust particles smaller than 10 microns in diameter (PM10 dust) has been linked to a variety of health problems, including asbestosis, silicosis, and coal pneumoconiosis (black lung disease), lung cancer and cardiovascular diseases. Furthermore, higher dust levels increase employees turnover, as they leave the company for cleaner work environments.
This is due to the fact that these dust particles are so minute that they can easily pass through the lower respiratory tract. Dust can compromise safety by obstructing vision and lowering vehicle traction. Underground mines are already hazardous environments to work in. Maintaining a clean air supply and good visibility is crucial with so much activity going on in such limited places.
Health impacts on the staff and surrounding communities
Inhalable or inspirable dust particles are bigger particles that can be breathed in. Dust particles that can be inhaled are visible to the human eye and settle in the nose, throat, and upper respiratory tract. Respirable dust is made up of microscopic dust particles that are invisible to the naked eye and penetrate deep into the lungs.
The health effects of various types of dust particles vary. Respirable crystalline silica dust, for example, causes lung scarring, while inhalable lead dust can harm the central nervous system. Many occupational diseases are the result of years or decades of dust exposure, and symptoms may not appear for years or decades.
Dust accumulation can also limit sight and pose a safety risk. Underground explosions are frequently caused by coal dust. In all mining operations, particularly underground coal mining operations, preventing subsurface explosions and their disastrous effects must always be a top concern.
Dust is harmful to the environment
Like people, dust harms the plants and animals with which it comes in contact. Airborne dust can travel long distances and end up contaminating crops, natural habitats or water sources such as rivers and irrigation infrastructure.
Dust damages equipment and reduces productivity
Dust is abrasive and can accumulate inside vehicles and other machines. At first, dust accumulation may mean just having a dirty windshield or some peeling paint, but problems caused to machines by dust accumulation can significantly reduce their working efficiency.
Accumulated dust inside a vehicle can cause steering tears, impede proper handling, or reduce airflow to components that should remain ventilated. One of the benefits of using dust suppression on construction sites and other workplaces where machinery is common is that equipment maintenance will be much less hassle, as wear and tear associated with dust will be minimal.
Likewise, the loss of visibility caused by dust reduces the speed of operation on haulage roads, loading and unloading fronts, and crushing warehouses.
Dust suppression increases workplace safety and reduces staff turnover and absenteeism
Purchasing a dust suppression system will improve the overall health and safety of all workers and reduce staff turnover and absenteeism. Dust makes vision and communication difficult, which can sometimes decide the outcome of a life or death situation. The durability of the equipment can also be affected by dust, increasing the chances of accidents. Dust in the short term generates eye problems, transmits diseases such as bacteria and viruses and is uncomfortable for workers, which causes them to migrate to cleaner jobs, or to report sick more frequently.
Dust can get anywhere, and that includes the inside of safety glasses. Someone operating machinery could suddenly get some dust in their eye, leading to rough handling of the equipment, possibly causing eye damage or a fatal accident.
Along the same lines, the dust lodged inside the equipment could create layers of sediment, which can cause problems such as impeding the flow of air and obstructing the torque of the gears. A sufficient amount of dust without proper maintenance can cause vehicles and machines to break down or even catch fire.
3 Innovative solutions to control dust in mines
1. Dust suppression: Optimized to the reality of your mine or site
Dust Master Systems (DMS®) provides a comprehensive spectrum of cutting-edge dust suppression additives for a variety of industries, including mining, forestry, and construction.
DMS® dust suppression products are made up of patented blends of nano polymers, enzymes, stabilizing agents, and high-strength, long-lasting, and safe nanomaterials. DMS® products are designed to provide cost-effective dust management and soil stabilization solutions for a variety of soil types, traffic conditions, and weather conditions.
DMS® high-performance dust suppression solutions and soil stabilizers are combined with electronically controlled irrigation equipment, Dust and Road Friction georeferenced monitoring systems, and Roughness georeferenced monitoring systems by ABC Dust. This connection improves ABCDust solutions, allowing us to better optimize our dust suppression and soil stabilization according to the operational reality of your task, lower expenses, and save time and money for our clients.
Our products are used where and when they are needed, resulting in higher road productivity, sustainability, and safety. Such products include:
- DMS-DS® is a very effective vehicle for dust suppression. It is typically used for suppressing dust on mining roads and highways.
- DMS-DS 100®: biodegradable soil stabilizer and dust suppressant, very effective for medium and large mining, with hydrophobic effect which reduces water erosion.
- DMS-EB® is an ecologically friendly modified bituminous emulsion designed to trap particle material (dust control) and increase road stability and safety (soil stabilization).
- Our low-cost dust suppression and soil stabilizer, DMS-DS 80®, has ultra-low chloride levels and is environmentally benign.
- DMS-TDS® is a non-ionic dust suppression technique that can be used on conveyor belt lines’ loading fronts and/or high-frequency material transport systems.
What are the benefits of ABCDust’s dust suppression management?
- Dust reduction has been demonstrated to be between 95 and 99 percent
- Water savings of 80-90 percent
- It is non-corrosive to machinery and has a neutral PH
- It can be used on any sort of soil
- It is designed for big machinery with a high volume of traffic
- Products that are non-toxic
- Environmentally friendly
Using our state-of-the-art suppression solutions and equipment to implement dust suppression at your site or facility will increase the safety of your site and your personnel while they are at work.
Dust suppression not only suppresses dust, but it also reduces the likelihood of hazards caused by dust, such as fire and illness, by lowering dangerous material in the air at your operation. It also makes it cleaner! Dust may be controlled and suppressed using some of the best dust suppression devices on the market. Contact ABCDust now if you are looking to invest in a state-of-the-art service!
2. Advanced dust monitoring equipment
Being able to measure the amount of dust in the air is one of the challenges of attaining efficient dust control. Underground mines would otherwise have no knowledge which sections require specific remedies. A dust monitor is a real-time dust concentration monitoring device that employs the most cutting-edge technology to measure dust concentrations, as well as wind speed, direction, humidity, and temperature.
When mining activities are carried out, dust levels will undoubtedly rise and fall, especially when blasting and drilling are carried out. As a result, underground mines must constantly monitor the volume and size of dust particles in the air in order to respond to any spikes in dust levels, particularly PM10.
3. Dry mist and spray systems for dust control
There are a variety of spray-on dust suppression products that may be used on haul roads in underground mines that are far more effective than simply using water. Bitumen emulsion binder products are the most modern solutions.
When opposed to other materials, a benefit of bitumen emulsion is that the bitumen residue remains in the haul road material without leaching. When sprayed in a succession of mild dilutions, bitumen emulsion binder products like DASProduct establish an impermeable seal that lowers dust formation. When applied correctly, DASProduct reduces dust levels on haul routes in underground mines by 90% or more.