Safety in Open Pit Mining: How about Processes?

Understanding Risks in Open Pit Mining

The development and implementation of strict safety processes are based on a basic understanding of the risks inherent in open-pit mining. Very deep open pits have posed a great challenge since workers were exposed to falling debris, equipment collisions, and unstable slopes that may collapse suddenly. Added to that, weather factors such as heavy rain or strong winds further deteriorate the dangerous condition by compromising structural stability or reducing visibility. Suppose explosives are used to break down the rock. In that case, even greater danger is involved, and very careful planning and exactness in placement and firing must be strictly observed in order to avoid accidents and injuries.

In order to deal with all these various hazards, a safety approach on all fronts is going to have to be employed: extensive training programs regarding site-specific risks, the use of sophisticated engineering controls that will stabilize both slopes and machinery, the use of new technologies providing real-time condition monitoring, and tight operational protocols minimizing accidents.

Safety in Open Pit Mining: Geotechnical Hazards

Geotechnical hazards in mining include two major classes: unplanned rock slope movements and rock falls. These hazards have severe consequences: possible fatalities, serious injuries, infrastructure damage, and losses of millions of dollars as a result of stopped production. Rock falls are among the biggest safety concerns in both underground and open-pit mines; therefore, effective risk management is crucial to prevent injury to personnel, equipment, and operations.

A rock fall is understood as a fragment or block of rock falling down a vertical or sub-vertical cliff along the slope. The fragments may be small cobbles or enormous boulders with hundreds of cubic meters at velocities between tens of meters per second. Based on such risks, protection systems against rock falls are generally classified into active and passive measures.

Active protection methods are designed to prevent instability before it occurs. Active protection systems are directly attached to the rock faces. These inhibit block detachment, which includes anchors, rock bolts, grouted bars, scaling, berms, excavations, and changes in slope and rock mass hydraulic conditions. If site conditions or other factors make direct attachment not feasible, then passive protection systems that will catch or arrest the falling rock are adopted.

Other passive protection methods include catch ditches, mesh drapery systems, and flexible rockfall barriers like catch fencing and embankments. Catch ditches are amongst the least expensive solutions, usually built on ramps and at the toe of high walls, often lined with gravel that provides impact energy absorption. Drapery systems, as widely used in surface mining operations, stabilize rock blocks and help control their fall in the event of a failure, therefore providing further protection for structures like portal structures. Together, these systems play a very significant role in the management of rock fall hazards and mining safety.

What are the basics of Safety in Open Pin Mining?

Training and education in open-pit mining are basically centred on safety considerations, enabling personnel to identify all possible risks and follow the most important safety prescriptions. On-site induction programs involve new employees with site-specific hazards and measures that must be taken to counteract them. In-service training puts all personnel abreast of changing safety practices, new technologies, and revisions in regulations. Effective communication is key in building a safety culture that ensures workers can point out hazards or unsafe practices without any form of reprisal. This helps achieve a more transparent and collaborative environment, leading to shared responsibility for safety.

The International Labour Organization has provided international standards on safety and health in the mining industry through the Safety and Health in Mines Convention, 1995 (No. 176), supported by Recommendation No. 183. The Convention calls for member states, in consultation with employers' and workers' organizations, to develop, implement and review a national policy on mine safety and health. National legislation should provide for a competent authority responsible for the supervision of mine safety regarding operation control, mine inspection, accident reporting, and suspension of activities for safety reasons when necessary. It is the responsibility of the employer to identify and manage risks to achieve safe design, construction, and maintenance of mines. He shall provide adequate ventilation for underground workings, draw up plans for emergencies, and make available proper personal protective equipment. Workers have rights like reporting hazards, withdrawing from unsafe conditions and getting training and information on safety and health. These regulations are designed to prevent fatalities, injuries, and illnesses within the mining industry by guaranteeing decent conditions and a healthy work environment.

How to Manage Explosives in Open Pit Mining?

One of the critical safety considerations in open-pit mining is the concern of explosives, which requires strict adherence to safety regulations and a lot of planning. Open pit blasting must fall under the "Blasting Safety Regulations," which prohibit blasting in any area where thunderstorms, foggy conditions, or night-time may occur. The methods of blowing up rocks using explosives are carried out by certified individuals and under tight regulations that guarantee the safety of people on-site and the surrounding communities. Pre-blast surveys often assess the potential risks and the danger zones, which are also clearly bounded to maintain enough safety distance from the source of the blast and are often reinforced with guard posts or warning signs.

Modern blasting methods employ electric detonators to improve precision and eliminate the chances of a misfire. Before firing, there should be warning signals and fire warning precautions must be taken. The unauthorized people are prevented by clear demarcation of safety zones. After firing, the staff cannot enter the site for certain periods and are allowed to enter only after a thorough checkup regarding safety aspects. Besides, proper storage, handling, and disposal of explosives will prevent accidents and improve adherence to regulatory standards for the safety of all operating persons.

Explosives used in mining are chemical compounds or mixtures that react at high speeds, releasing gas and heat which generate high pressures. High explosives detonate while low explosives deflagrate. Both types of explosives can be initiated using a single No. 8 blasting cap, which is not possible with blasting agents. Blasting agents are slow-burning compositions used in initiation systems, such as detonators, detonating relays, and fuse heads. These four major categories are divided into explosives. Representing the categories of high explosives are TNT, dynamite, gelatins, hybrid charges, ANFO, slurries, emulsions, and ANFO-slurry mixtures. The category for low explosives is black powder. Special explosives include seismic explosives, trimming explosives, permissible explosives, shaped charges, binary explosives, LOX, and liquid explosives. Explosive substitutes will include expanding agents, mechanical methods, water jets, jet piercing, and compressed air.

OSMRE recognizes that people are sensitive to blast vibrations and that blasting can be perceived by people at levels as low as 2% of the legal vibration limits. Thus, even blasts that meet the legal standards for vibration may create annoyance when the resultant shaking is sufficient to rattle homes. Annoyance is a matter of individual sensitivity, and certain individuals can consider any given blast objectionable. Although OSMRE does not regulate such annoyance, the regulations account for the need to provide advance warnings. For the purpose of reducing annoyance, the regulations require audible warning signals from ½ mile away that serve to alert the public of impending blasts. The meaning of these signals and the exact blasting times are given in a notice of blasting schedule, which is sent to residents within ½ mile of the blast site. Moreover, residents within ½ mile of coal mining permit boundaries may request notice as part of a pre-blasting survey of their home. (1)

Safety in Open Pit Mining: Traffic Management

The safety of open-pit mining operations also depends on effective traffic management and road safety. Roadbeds should be solid, reliable, and have flat surfaces so as to allow heavy machinery on them. Given the large-scale vehicles for mining, appropriate passing lanes should be constructed on bends, hillside fills, and steep sections, which permit smooth passage without congestion that leads to collisions. The roadsides are built with barriers or stacks of safety and protective systems to avoid accidents due to falling or overturning of vehicles, and drainage ditches are made to avoid the accumulation of water, which might destroy the road. Vehicles moving over mining roads should run at safe speeds, especially in areas with sharp bends, steep slopes, or hazardous areas, placing road signs and warning signals to direct drivers and help them avoid accidents.

Management of traffic within the mining pit is one of the very critical aspects of safety. This involves carefully coordinating heavy machinery, haul trucks, and other vehicles. The haul roads are well-marked, and there are particular traffic patterns to organize movement. Speed limits are strictly observed, and traffic management plans are continuously reviewed and updated in order to respond to the ever-changing conditions of the mine. The operators are well-trained to manage the vehicle safely in complicated and high-pressure conditions. Fatigue management programs are designed to minimize accidents from human errors. Besides, periodic vehicle maintenance is compulsory to maintain them in a good working state for safety and efficiency under harsh mining site conditions.

FAQ

What are some common hazards found in open-pit mining?

Open-pit mining has a lot of associated hazards with respect to its size and operation. Common hazards include falling debris from unstable slopes, vehicle collisions, and malfunctions of equipment. Workers are also exposed to environmental risks such as dust, noise, and extreme weather conditions. Further risks were brought by explosives, including misfires or unintended rockfalls. Only comprehensive safety measures regarding proper training, engineering controls, and deployment of advanced monitoring systems can avoid these risks and make it safe for workers.

How do ILO standards lead to improvement in safety in open pit mining?

Compliance with ILO safety standards enhances good mining practices by stipulating that the working conditions should guarantee safety and fairness for the workers. In fact, the standards bind employers to regular risk assessments, provide adequate training, and facilitate access to personal protective equipment. The adherence to such guidelines on the part of mining companies guarantees a minimal rate of accidents, boosts worker morale, and is proof of their commitment to international best practices. Additionally, adherence to ILO standards fosters collaboration among workers, employers, and regulators, creating a safer and more productive mining environment.

Takeaway

Safety in open-pit mining is not singular but multi-layered; every differentiating risk associated with the industry demands a wide-ranging and holistic approach. Every minute detail related to safety, from the most rigid training programs and sophisticated engineering controls to using innovative technology and preparing for contingencies, needs to be well-thought-out and implemented, as well as embraced for continuous improvement. Workers' welfare is of most importance, not only in physical but also in their psychological health, as mining is one of the most demanding jobs, which takes mental toughness. It is impossible to separate environmental safety from the safety of workers since dust, noise, water hazards, and vibrations are all significant factors in the protection of workers and communities. This is further enforced by regulatory compliances and adherence to international standards put forth by the International Labour Organization. With investments in new technologies, an open dialogue with the relevant stakeholders, and a proper safety culture, safety is considered one of the core values and not related to compliance alone can mitigate risks drastically. Continuous improvement supported by lessons learned from incidents and practice innovation ensures mining operations evolve to address emerging challenges.

Ultimately, the integration of robust safety measures not only protects life and property but also secures the long-term viability and reputation of the open-pit mining industry. Further aligning its operations with global best practices and with the well-being of all concerned in mind, open-pit mining should be able to achieve responsible, sustainable development for the good of workers, the environment, and the greater society.

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GLOSSARY

Trinitrotoluene (TNT) - is a widely used explosive in military, industrial, and mining applications. It has also been employed in hydraulic fracturing, commonly known as fracking, a method for extracting oil and gas from shale formations. This process involves displacing and detonating nitroglycerin in hydraulically induced fractures, followed by wellbore shots using pelletized TNT.

TNT is particularly valued for its insensitivity to shock and friction, which significantly reduces the risk of accidental detonation compared to more sensitive explosives like nitroglycerin. It melts at 80 °C (176 °F), well below its spontaneous detonation temperature, allowing it to be safely poured or combined with other explosives. Additionally, TNT is neither absorbed by nor dissolves in water, making it suitable for use in wet environments. To detonate, TNT requires a pressure wave generated by a starter explosive, known as an explosive booster. (4)

Sources:

(1) https://www.osmre.gov/programs/regulating-active-coal-mines/blasting

(2) https://www.911metallurgist.com/blog/open-pit-mining-safety/

(3) https://www.ilo.org/sites/default/files/wcmsp5/groups/public/@ed_dialogue/@sector/documents/normativeinstrument/wcms_617123.pdf

(4) https://www.britannica.com/science/trinitrotoluene

Author

Michal Wozniakowski-Zehenter, Marketing Manager

Michal Wozniakowski-Zehenter is an experienced marketing and project management professional. He spent most of his career on projects with a strong focus on digital marketing and event management. He is a very active voice representing offshore and mining industries through social media channels. Michal writes mainly about offshore oil and gas, renewable energy, mining and tunnelling. Compiling and sharing the knowledge within industries is one of his goals.

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