Read about some of the hazards in mining workplaces and employers’ responsibilities under the Occupational Health and Safety Act (OHSA) and its regulations. You can also contact your health and safety association for guidance on controlling hazards.

Ground control

Ground instability is one of the biggest causes of fatalities in underground mines in Ontario.

Falls of ground or rockbursts occur when rock becomes dislodged from the roof or walls of an underground excavated site. The amount of rock displaced can vary from hundreds to thousands of tonnes of material.

As underground mines become older and deeper, there is a greater chance of ground instability. There are several underground mines in Ontario operating at depths approaching 3,000 metres.


Water management

Workers can suffer serious injuries or deaths when water accumulates underground in mines.

These hazards can be prevented by ensuring:

  • a water management program is developed and maintained in the workplace
  • pumping systems (sumps) have the means to conduct the removal of excess water from the workplace
  • the associated infrastructure related to the pumping system is maintained and kept free of obstructions (drain holes, drain lines)
  • there is workplace awareness of how the improper use of water can lead to dangerous and catastrophic outcomes
  • the area is adequately barricaded to prevent access. By law, the employer and the supervisor shall not permit any worker to enter that area unless the purpose of the work directly relates to managing and removing water, and all reasonable precautions have been taken to protect workers.

Employers are responsible for protecting workers from hazards associated with the improper use or accumulation of water.

Some of the hazards include:

  • an unexpected or unannounced run of material caused by the infiltration of water into material handling systems
  • drowning caused while maintaining the pumping system or when clearing obstructions from a drain hole which then creates very powerful suction through the hole
  • musculoskeletal disorder (MSD) injuries caused by hidden hazards underneath accumulated water

Water has many uses in the underground environment but it is one of the top mining hazards. Inspectors write numerous orders related to water accumulation, lack of proper barricades to warn workers of hazards and failure to properly document these hazards in the supervisor’s log book.


Remote control equipment

Remote control radio technology is widely used to operate equipment in mines. This involves equipment that is controlled by an operator using remote joystick controls. It can be used close to where the equipment is operating or at locations that are totally isolated from the equipment (operated from surface control room). Remote control technology can be used to remove workers from unsafe conditions where there would be risk from using other methods.

Workers can be seriously injured or killed if proper methods and procedures are not used when operating remote controlled equipment.

Hazards include:

  • being struck by or run over by equipment
  • being crushed between equipment
  • contact between unsecured work platforms and equipment
  • runaway equipment



The quality and safety of explosives and blasting methods have greatly improved over the years. However, there are still serious hazards involving the storage, transport and use of explosives.

Explosives must be stored to protect them from the elements and from any conditions that could cause them to degrade, becoming less safe and reliable. An explosives storage area must be constructed to:

  • minimize inadvertent ignition
  • protect nearby workers, the general public and structures if explosives ignite

The public must be protected by ensuring stored explosives are accessible only to authorized workers and used solely for their intended purpose.

Explosives can be dangerous. Proper precautions must be taken to protect workers. Only competent and trained workers should handle explosives and extreme care must be used.

Safe practices

Maintenance/inspection of explosives magazines and equipment

Magazines (buildings, locations or containers) that store explosives must be maintained in a clean and orderly condition. Mobile equipment and tools must also be maintained in good and safe condition if they are used in the handling of explosive products.

Explosives inventory methods

Employers must control inventories of explosive products underground and on the surface (for example, keeping log books). They must have procedures in place to ensure the oldest explosives are used first. Inspection reports must include details on the quantities of explosives stored. These measures are required because the quality of explosives degrades over time, making them potentially volatile and hazardous. Workers can also be at risk if incompatible products are improperly mixed during blasting operations.

Procedures for safe disposal of damaged explosives

Employers and their joint health and safety committees (JHSCs) must develop written procedures for the safe disposal of damaged explosives and communicate them to workers. This prevents workers from using damaged explosives, and helps them to handle damaged explosives properly.

Proper handling during transport and use

Employers must develop proper procedures for workers to handle explosives when they are using or transporting explosives. The moving of explosives between magazines and workplaces must occur without delay. Vehicles carrying explosives must always have the right of way. Explosives must never be left unattended and/or improperly disposed of.

Employer’s reporting requirements

Employers must notify the Ministry of Labour, Immigration, Training and Skills Development of:

  • the use of explosives and installation of surface explosives magazines
  • any incident involving the mishandling of explosives
  • an uncontrolled or unexpected explosion and any defective explosive products

Worker training

Any worker who uses or handles explosive products or who may be affected by them must be trained in safety procedures. Workers must successfully complete the relevant training required by the OHSA and its regulations, including modular training programs required under the regulation for mines and mining plants. Workers must know what explosives look like and what to do if they are not placed or used properly.


Mobile equipment

Workers can suffer injury or even death from hazards involving motor vehicles and mobile equipment at underground and surface mines.

Employers are responsible for protecting workers from motor vehicles and mobile equipment hazards in mines.

Establishing traffic management programs with traffic control policies, measures and procedures can help prevent hazards and protect workers. Traffic management programs can include measures such as high-visibility clothing, effective lighting, monitoring work conditions and education and training.

Hazards include:

  • being struck or run over by equipment
  • being crushed between equipment
  • falling off mobile equipment while performing maintenance
  • driving into an unguarded open hole underground

In the past years, inspectors have found that mine operators need better maintenance of equipment that helps operator visibility, as outlined in the regulation for mines and mining plants. This includes fixing or replacing broken or shattered windows, missing mirrors and inoperative lights. Equipment operators should also check and ensure that the equipment is safe to use. Lighting required for work areas should be in place and maintained.

Employers must develop a traffic management program in consultation with the joint health and safety committee (JHSC) or the worker health and safety representative in the workplace.


Modular training

Modular training programs consist of individual training modules developed by ministry in consultation with industry and labour representatives on the Mining Tripartite Committee.

Employers must register workers in the appropriate training program. Completed training is accredited by the ministry as a permanent record of the training.

To ensure a safe workplace for all mine workers, employers are required to develop specific training, based on the Ontario government’s standardized course materials.

Training programs are required for:

  • hard rock mines such as nickel, copper, gold and diamond mines
  • soft rock mines such as salt and gypsum mines
  • surface mines such as sand and gravel operations and pits and quarries
  • diamond drill exploration sites underground and on the surface
  • supervisory training for mine supervisors

The training requirements are set out in the regulation for mines and mining plants.

The Ministry of Labour, Immigration, Training and Skills Development is responsible for enforcing the training requirements at all Ontario mines and mining plants. Employers must provide proof of this training to mininstry inspectors on request.

Violations can result in serious injuries to workers in mines, mining plants and at exploration sites.

Mine operators can prevent incidents by ensuring that proper training programs are developed and maintained. Properly trained workers have a better chance of staying safe on the job.


Occupational illness and diseases

While traumatic fatality incidents in the mining sector have declined substantially over the past several decades, deaths from occupational illness have not.

Miners working in a closed underground environment can be exposed to airborne hazards such as diesel emissions and silica that put them at higher risk of developing occupational illness.

Recent research revealed that some components of emissions from diesel powered equipment are carcinogenic. Significant continuing research has been done to develop filters to eliminate the harmful effects of diesel exhaust and to identify the optimum diesel fuel type for producing the least harmful emissions.

The Mining Review focused on airborne disease hazards such as diesel particulate matter and silica in underground mines. It identified opportunities to:

  • raise awareness among workers and employers of the importance of controlling risks to health in underground mines
  • increase understanding of the health effects of exposure to diesel emissions in underground mines and improve controls
  • review and update occupational exposure limits for airborne hazards in underground mines
  • identify and publicize options to monitor ventilation in underground mines to reduce concentrations of airborne hazards

Mine operators must:

  • focus on controlling dust, maintaining ventilation systems and providing enough ventilation in areas where diesel equipment is operating
  • ensure that there is enough ventilation to dilute contaminants in the workplace and that maintenance and good work practices are used to control mining process dusts


Mining health and safety guidelines

Find more resources on workplace health and safety.