| Written by Michal Wozniakowski-Zehenter
According to the National Institute for Occupational Safety and Health (NIOSH), just in the United States of America in 2021 shows that while fatal incidents in the mining industry are trending to be reduced, still risks are present. More than 2/3 of those incidents involved mining equipment, such as powered haulage (45.91%) and heavy machinery (21.62%). Meanwhile, the mine itself posed a major risk with loose material and falls of ground for another 13.52% of fatalities.
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ELEMENTS OF miners SAFETY
You can differentiate many aspects of miners safety. All of them cover slightly different parts of the industry, combined giving a full scope of responsibility for safe operations. While the fundamental principle of mine safety is to avoid health risks to mine workers, during this time evolved also to focus on the reduction of potential hazards to the machinery, and structure of the mine.
The following topics are most common while discussing miners safety:
- General safety - General aspects of safety which are common to all types of mines (electrical and machine safety)
- Occupational safety and health - Issues particularly associated with mining. These include blasting explosives, ergonomics, diesel and dust control, hearing loss, etc.
- Process and production safety - Safety within the processes associated with mining
- Workplace safety - Safety issues directly related to the workplace as ventilation to name one
- Fire and explosion safety - In particular, the risks associated with fires and explosions in the mining industry
- Structural safety - Safety in mine construction and geologic characterization
- Environmental safety - Issues of environmental safety (direct or indirect impact of the mining industry)
Miners safety: VENTILATION
One of the first technologies used to improve miners safety is ventilation. Ventilation is a critical aspect of mining operations, as it is essential to ensure that the air in a mine is clean, safe, and breathable for workers. Mining activities generate a significant amount of heat, dust, and toxic gases, which can be harmful to the personnel if not properly ventilated.
There are two main types of ventilation systems used in mining: natural and mechanical.
- Natural ventilation relies on the natural airflow in and out of the mine. This system uses natural pressure differences created by temperature and altitude to draw fresh air into the mine and exhaust stale air. It is typically used in small mines or areas with low levels of gas and dust.
- Mechanical ventilation uses equipment to move air in and out of the mine. This system uses fans, ducts, and other equipment to create airflow through the mine. Mechanical ventilation is typically used in larger mines or areas with high levels of gas and dust.
Each method has its own set of pros and cons. First, let’s look into the advantages and disadvantages of the natural solution. It is often cheaper to install and maintain than mechanical ventilation systems. Since it doesn't require any additional energy source, it can be considered an energy-efficient alternative. Natural ventilation systems are easy to design and maintain and do not require any sophisticated equipment or technology. On the other hand, this solution is dependent on external factors such as weather conditions, air currents and the layout of the mine itself which may make it impossible to use natural ventilation.
Mechanical ventilation provides consistent and precise control over the quality of the air, ensuring that it meets safety standards. It can deliver air to the very remote parts of the mine, making it possible to ventilate areas that are difficult to reach with natural ventilation. Those systems can easier reduce the risk of exposure to harmful gases or particles that might be present at a time. It enables to have Ventilation on Demand (VOD) which is an intuitive system with software capable of scheduling airflow to different parts of the mine based on a daily schedule or by measuring environmental factors and the location of miners and assets. But they are very expensive to be installed and maintain properly. It might need a more complex design and additional equipment and technology. Mechanical ventilation requires a secondary energy source to operate, which leads to higher energy consumption and associated costs.
Ventilation in mining can be challenging due to many other factors. The deeper a mine is, the greater the pressure and temperature, which can make it more challenging to maintain proper airflow. The location of a mine can also present issues, areas with high humidity or low atmospheric pressure may require more complex ventilation systems. Large mines may require multiple systems to ensure adequate airflow throughout the mine. Operators must balance the cost with the benefits of improved air quality and safety. They require regular maintenance to ensure their correct functionality. This can be challenging in remote locations or with limited resources.
It should be designed to support the airflow in cross-sectional areas of the mine, depending on the type of mine, its location and local law requirements. Many governments regulate a minimum air velocity to guarantee a healthy environment during operations at the level of 0.3 m/s. When ventilation is poorly managed or not inspected regularly it may lead to gas poisoning, asphyxiation, dehydration, overheating and injuries of the personnel. It might also be the reason for spontaneous combustion or frictional ignition which leads to explosions and fires.
This technology is used in almost all mines, especially in big and medium operations.
miners safety: METHANE SENSORS
Around 60% of coal is currently being extracted worldwide in underground mines. As a consequence of that, miners work in confined spaces, deep down shafts. One of the major problems is releasing Methane (CH4) as a part of Mine Gas together with Nitrogen (N2), Carbon Dioxide (CO2), and Oxygen (O2), a natural product of the carbonisation process. The concentration of methane depends upon the quality and depth of the coal seam. the higher the energy value of the coal and the deeper the coal bed is, the more CH4 occurs. Also, with blasting operations, Carbon Monoxide (CO) might occur in large quantities. All of it can cause a real fire and explosive risk.
There are two main types of methane sensors used in mining: catalytic and infrared sensors.
Catalytic sensors work by oxidizing methane in the presence of a catalyst, producing a measurable change in the electrical conductivity of the sensor. When methane gas comes into contact with the catalyst, it produces heat, which is detected by the sensor. The heat generated by the oxidation causes a change in the resistance of the sensor, which is then measured and used to determine the concentration of the gas in the air.
Infrared sensors work by detecting the absorption of infrared light by methane gas. The gas absorbs infrared light at midrange wavelengths (MWIR), which can be detected by a sensor. The amount of infrared light absorbed by the gas is measured, and the concentration of methane gas in the air is determined. Those monitors must provide a warning whenever the concentration level of methane will exceed 1% and reach 5% when mounted on the machines. Several mining operations also use small, portable detectors clipped to an item of clothing to keep workers safe and perform hands-free monitoring. Most of them are connected to alarm systems with sound (sirens) and lights (strobes or flashing) signals for safe evacuation in an emergency.
With obvious pros of using this technology, naming improved safety, compliance with regulations, cost-effectiveness and ease of use, there is a couple of obstacles while using methane sensors. They can sometimes trigger false alarms, which can cause unnecessary evacuations, due to the factors such as changes in temperature, humidity, or air pressure, which can affect the accuracy of the detector. False alarms can be disruptive to mining operations, as they can cause delays and increase costs. Limited coverage of the areas, can be also a concern as there may be pockets of methane gas in the mine that are not being detected.
Due to regulations, sensors are used in all coal mines (i.e. in Australia, it’s mandatory according to Coal Mining Safety and Health Act from 1999)
miners safety: RTLS
Real-Time Location System detects signals from transmitting tags to determine the real-time position of the tag (learn more about blasting safety).
They are used within indoor or underground areas where GPS satellites are neither available nor reliable, based on mostly Bluetooth, Wireless Fidelity (Wi-Fi), or Ultra-wideband (UWB) transmission. It is based on triangulation – setting location sensors to determine the position of a tag within the range. The advantage of an RTLS solution is not only to have a real-time overview of the entire inventory, the machines, as well as single crew members but also to retrieve and analyse processes. It is also used in tracking personnel during emergency response procedures as well as optimizing operations. Wi-Fi solution tends to require a large amount of power to operate while Bluetooth presents challenges in signal strength, making it difficult to locate a device. Recent trends show that UWB has proven better reliability in combination with higher accuracy transmission, where 2.4GHz frequencies are blocked by obstacles.
Increased safety is one of the fundamental benefits of a real-time location system. With real-time monitoring of personnel and assets, it is possible to instantly respond to any occurring incidents. RTLS also helps to minimise the risk of accidents and improve the overall safety of operations.
On the downside, the implementation of this technology can be expensive with initial costs associated with hardware, software and installation. It might raise privacy concerns among employees with tracking the exact location of the personnel. It can have limited coverage with poor wireless connectivity and might need an additional investment into infrastructure.
This solution is used i.e. in Los Pelambres, the 7th biggest copper mine in the world, located in Salamanca, Chile.
miners safety: RFID
Radio Frequency Identification has multiple functions in the mining industry, very similar to RTLS technology, from safety monitoring, through the positioning of assets and personnel to control access to the site.
The system consists of a small radio transponder, a radio receiver, and a transmitter. The tag transmits every few seconds digital data assigned to it – personal id, asset number, etc. – when triggered by an electromagnetic pulse from a nearby reader device. The best usage of this solution is to define zones with readers on both ends to determine movements or place one reader with a range of up to 300 meters. With low power consumption and ultralow costs of the tag, it is very efficient to be used in underground operations, without investing a lot into additional infrastructure to describe the location of the device.
In case of an emergency, this technology plays a very important role to coordinate first responders’ movements, guide them towards the most crucial personnel, identifying refuge chambers or life-saving gas masks and the best location for an escape. They also portray the clearance of the location of the blasting to make sure that explosives are only used at the right time when personnel are in the safe zone.
LKAB Company (the world’s biggest iron ore producer) uses this technology in Kiruna as well as in Malmberget and open pit operations in Svappavaara.
miners safety: GPR
Ground Penetrating Radar provides high-resolution images by using the electromagnetic spectrum (EMS) in the microwave band in the range between 10 MHz and 2.6 GHz. It consists of a transmitter that emits a pulse into the ground and detects echoes and a receiving antenna that records discrepancies in the return signal. This technology helps to make a change from the traditional ground investigation work of point-by-point drilling and sampling. A wide number of geologic challenges can be defined thanks to this technology such as structural integrity or jointing and cracking before extraction. It can give also the estimation for the stability of the rock mass, which can help prevent hazardous events such as cave-ins, and detect loose rocks or groundwater-bearing fracture zones. It supports the inspection of tunnels delivering data on thickness positioning and numbers of rebars, also showing voids and fractures. In that case mitigation of risks plays part in the safety of mine operations by collecting real-time data and providing high-resolution images of the subsurface.
On the other hand, there needs to be a skilled operator, having expertise in geology, geophysics and mining to collect the data in a proper way, which can be challenging in areas with high conductivity. Also, inaccuracy of imaging can be hard, especially with complex geologic structures.
miners safety: AUTOMATION
It’s a process of applying technology to remove human labour from mining operations. It can reduce the risk of injuries and diseases working in a harsh environment. There are several different forms of automation of mining equipment.
Remote-controlled machinery is the least expensive way to start automation yet the functionality is restricted. The operator with the handheld remote control needs to be in the line of sight of the machine, which is useful in areas with unstable terrain or falling debris, thus, with dimmed light and dust, precision is not at the highest level.
Upgrade to this solution is teleoperated equipment. It allows the operator to be in an even more secure space, having cameras and sensors, supported by different software as indicators of an operation. It still uses a joystick or handheld controller, but the accuracy of the operations is much higher. Both remotely controlled solutions might be used with excavators, dozers, ADTs and even haul trucks which reduces personnel in hazardous areas leading to lower risks for both drivers and miners working around industrial vehicles.
The most significant disadvantage of Automation is the loss of jobs as machines take over tasks previously done by human workers. Another one is the height of the initial cost. While in the long term, it will reduce costs, especially of human labour and improve efficiency, the cost of purchasing and installing the technology is very high, not to mention maintenance as an additional cost factor. Automated machines are programmed to perform specific tasks and may not be able to adapt to changes in the mining environment. This reduces the flexibility of operations, making them less adaptable to changing conditions.
This solution is widely used to some extent in many mines, but the Syama gold mine, located in Mali, became the first full-automated gold mine in the world.
miners safety: PROXIMITY DETECTION AND COLLISION WARNING
With the industry moving forward and covert new technologies to be used underground, Proximity Detection Systems (PDS) are becoming crucial control measure improving safety in moveable mining equipment. This technology detects people and vehicles in proximity of an equipped asset and alarms for an impending hazard. Some advanced solutions can take control of the movement and make an emergency stop during an impending collision. Those mostly capacitive sensors can detect metallic and non-metallic objects or sense the approach or presence of nearby objects without physical contact. Additionally, there are many PDS units and multiple sensing technology categories used such as radio frequency, infrared, radar, ultrasonic, LIDAR, and combinations thereof. Mine operators are increasingly installing these proximity detection systems on mining equipment in surface and underground mines to prevent pinning, crushing, or striking accidents.
The basis of most collision warning and avoidance solutions is a tracking system, which monitors the positions of personnel and assets (vehicles, machinery, etc.) and ensures they don’t come into contact with each other. It might be based on different technologies – Radars, lasers, and cameras with 3D LiDAR being named as one. This Light Detection And Ranging system scans with its laser the environment and creates a 3D representation of the surroundings. This solution is currently the most advanced since detects all objects (metallic and non-metallic, rocks, mining fronts, and any obstacle that might be considered a risk). Collision avoidance systems also include alarms and alerts that trigger when two tags are moved too close to one another, providing an early warning system to prevent accidents from taking place.
One of the biggest drawbacks of proximity detection systems is their cost. Implementing them can require significant investment in both hardware and software, as well as training for personnel to use them effectively. They can sometimes generate false alarms, which can lead to equipment operators becoming desensitized to the alerts. This can reduce the effectiveness of the system in preventing accidents. A collision warning is also not foolproof and may not detect all hazards. This means that workers may still be at risk, even with these systems in place.
Read more about underground mining safety equipment
Miners safety: DRONES
This technology is more common in open-pit mines, due to vast areas and the possibility of using a bird’s eye view perspective to monitor surroundings regularly. With the addition of different software & analysing platforms, high-resolution photography can be transferred into very detailed Digital Terrain Models (DTMs) for closer inspections in a 3D environment. Placing several temporary ground control points (TGCPs) and the quality of the drone camera’s accuracy of approximately 5 cm is possible. So, this, being said, we can differentiate various types of drones:
Mapping drones are designed to produce highly accurate maps of sites. They are equipped with high-resolution cameras and advanced mapping software that can create 2D and 3D maps of the area.
Inspection drones are used to surveil mining equipment, structures, and infrastructure. They are equipped with cameras and sensors that can detect defects, damage, and wear and tear. They can also be used to identify potential safety hazards and prevent accidents.
LiDAR drones use mentioned earlier, Light Detection and Ranging technology to create highly accurate 3D maps of mining sites. They emit laser beams that bounce back from surfaces, creating a detailed point cloud that can be used to measure distances and create 3D models. LiDAR drones are especially useful in operations where accuracy is crucial, such as in open-pit mines and underground tunnels.
Thermal drones are equipped with thermal cameras that can detect heat signatures. They are used to identify hotspots in mining operations, such as overheating equipment or potential fires. They can also be used to map areas where minerals are present, as different minerals have distinct heat signatures.
Delivery drones are used to transport small items such as tools, spare parts, and samples between mining sites. They are equipped with GPS and can navigate difficult terrain, making them ideal for mining operations in remote locations.
On the other hand, drones are limited by their battery life and range, which can decrease their usefulness in mining operations. Additionally, they may not be able to operate in all weather conditions and close to restricted or sensitive areas (i.e. airports or military zones).
They are widely used in mining operations, naming Campamento Minero in Bolivia as one.
miners Safety: WORKSITE SIMULATORS
Mining simulators are designed to provide effective training for operators of machinery in complex and hazardous scenarios within a completely safe environment. This portable solution, with a Virtual Reality headset, enables users to enter a virtual worksite and have an opportunity to better understand their future working conditions, the equipment they will be responsible for, and any potential scenarios which might occur in real life. We can differentiate Earthmoving simulators to train operators of bulldozers, excavators and loaders, drill simulators for drill rigs and rotary drills equipment and haul truck ones for drivers of those huge machines.
Those advanced simulators not only can reduce training costs and use of the equipment but mostly can help to reduce hazardous situations, avoid human errors and train desirable behaviour of the personnel. Experiencing even the toughest accident in the virtual world translates to a calmer and more proper reaction to the same situation in reality. It can also serve as a retraining tool for already experienced workers, to remind procedures of an emergency machine failure etc.
One of the biggest users of this technology is Rio Tinto Mining Company with mines in Western Australia, North America and Africa.
Takeaway
The usage of new technologies in every branch of business is remarkable. It’s no different in the mining industry (read more about the safety framework in mining). Most of them are well-known and introduced in many operations globally, some are just newly introduced but gaining new users year by year. Having miners safety as a priority will always push the industry to search for newer and better solutions to save lives and mitigate risks. Usage of them depends on the set-up of the operation, the budget and the possibility of seamless integration of the new system into an existing environment.
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