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Water Management in Underground Mines

Safe At Work Ontario
  • Issued: January 29, 2015
  • Content last reviewed: January 2015

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.


Water accumulation and related hazards can put workers in underground mines at risk. These hazards can cause serious injuries, and even death, to workers.

Incidents can be prevented by ensuring:

  • Pumping systems (sumps) are capable of removing excess water from the workplace.
  • Associated infrastructure (drain holes and lines) for pumping systems are maintained and kept free of obstructions.
  • Workplaces are aware of how the improper use of water can have very dangerous and catastrophic outcomes.

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

Some hazards workers can be exposed to include:

  • An unexpected or unannounced run of material (dirt or ore) caused by infiltration of water into material handling systems.
  • Workers drowning while performing maintenance on a pumping system, or getting trapped while clearing obstructions from a drain hole that can cause powerful suction.
  • Trips and falls on hazards such as rocks or other material hidden beneath accumulated water, causing musculoskeletal disorders.

Between 2000 and 2014, three workers died in Ontario mines after being engulfed by runs of material due to the material being saturated with water.

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 their 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 for the protection of workers.
  • Ensure equipment, materials and protective devices required by the regulations 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.


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/or worn by workers.
  • Advise workers of any potential or actual health or safety dangers known by the supervisor.
  • If prescribed, provide workers with written instructions about measures and procedures to be taken for the workers’ protection.
  • Take every precaution reasonable in the circumstances for the protection of workers.


Below are some examples of workers’ OHSA duties:

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

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

Protecting workers

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

Compliance information

Toll-free number

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.