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Ground Control in Mines

Safe At Work Ontario
  • Issued: September 29, 2014
  • Content last reviewed: September 2014
  • See also Mining

Disclaimer: This resource has been prepared to help the workplace parties understand some of their obligations under the Occupational Health and Safety Act (OHSA) and regulations. It is not legal advice. It is not intended to replace the OHSA or the regulations. For further information please see full disclaimer.


The collapse of excavated rock or stockpiled material found in underground and surface mines can cause health and safety hazards for workers. These hazards can result in serious injuries and even death to workers.

Proper-engineered design practices for ground control, along with workplace inspections prior to the beginning of work can prevent these hazards.

Employers are responsible for protecting workers from ground instability.

Some of the hazards workers can be exposed to include being:

  • Struck or crushed by loose material that either falls, dislodges or is ejected from the ceiling, walls or ‘face’ (wall surface).
  • Engulfed by material like gravel and rocks that has been stockpiled to high or too steep, causing the material to flow unexpectedly.
  • Struck or crushed in the colder months by stockpiled frozen material that contains moisture. The large chunks of frozen material can crush equipment if it is dislodged by the activities going on near a stockpile.

Ten workers died in Ontario mines between 2000 and 2014. Of those, eight were in incidents in underground mines, with three happening this year. The two other fatalities involved an unexpected run of material from a stockpile in surface mines.

In addition, 47 other workers received critical injuries because of ground instability between 2000 and 2014. Of those, 44 were working in underground mines and three were working in surface mines.

In a recent risk ranking assessment conducted as part of the provincial Mining Health Safety and Prevention Review, four of the top five highest-ranked risks were ground control issues. Underground rock bursts were identified by labour and employer representatives as having the highest degree of risk of more than 250 assessed risk factors.

Some general duties of workplace parties


Employers have the greatest responsibility for health and safety of their workplace. Employers must provide information and instruction to workers on how to ensure health and safety in the workplace (e.g. information about safe work policies and procedures specific to the workplace and the type of work being performed).

Below are some examples of employers’ duties under the Occupational Health and Safety Act (OHSA):

  • Provide information, instruction and supervision to workers to protect their health and safety.
  • Take every precaution reasonable in the circumstances to protect workers.
  • Carry out prescribed procedures in the workplace.
  • Ensure required equipment, materials and protective devices are provided and maintained in good condition.
  • Provide assistance to, and co-operate with, the mine’s Joint Health and Safety Committee and/or a health and safety representative.
  • Prepare and review, at least annually, a written occupational health and safety policy for the workplace and develop and maintain a program to implement that policy.
  • Post a copy of the OHSA in the workplace.
  • Ensure workers are able to raise health and safety concerns without fear of reprisal.


Below are some examples of supervisors’ OHSA duties:

  • Ensure workers comply with the OHSA and its regulations.
  • Ensure any equipment, protective devices or clothing required by the employer is used and worn by workers.
  • Advise workers of any health or safety dangers known by the supervisor.
  • Provide workers with written instructions about procedures to take for their protection.
  • Take every precaution reasonable in the circumstances to protect workers.


Below are some examples of workers’ OHSA duties:

  • Use or operate equipment in a safe manner.
  • Report defects in equipment to the supervisor or employer.
  • Work in compliance with the OHSA and its regulations.
  • Report any known workplace hazards or OHSA contraventions to your supervisor or employer.

Protecting workers

Workers should be aware of their OHSA rights, including the right to refuse unsafe work and the right to know about any hazards they may be exposed to in the workplace.

Employers, supervisors and trainers should encourage workers to communicate any questions or concerns they have about ground control hazards. Supervisors or others involved in training workers should be familiar with any health and safety concerns faced by the workers.

Compliance information

Call toll-free

Call 1-877-202-0008 anytime to report workplace health and safety incidents or for general inquiries about health and safety at the workplace. Always call 911 in an emergency.

Disclaimer: This web resource has been prepared to assist the workplace parties in understanding some of their obligations under the Occupational Health and Safety Act (OHSA) and the regulations. It is not intended to replace the OHSA or the regulations and reference should always be made to the official version of the legislation.

It is the responsibility of the workplace parties to ensure compliance with the legislation. This web resource does not constitute legal advice. If you require assistance with respect to the interpretation of the legislation and its potential application in specific circumstances, please contact your legal counsel.

While this web resource will also be available to Ministry of Labour inspectors, they will apply and enforce the OHSA and its regulations based on the facts as they may find them in the workplace. This web resource does not affect their enforcement discretion in any way.