To assist employers, workers and other workplace parties with understanding the requirements in Regulation 854 – Mines and Mining Plants under the Occupational Health and Safety Act, regarding risk assessments and risk management.


To provide information on how to:

  • assess workplace hazards and assign a level of risk to them
  • control workplace hazards
  • ensure that the appropriate workplace parties are involved in the required risk assessment and management processes
  • ensure that risk assessments are carried out at the appropriate frequency

Legal requirements

Sections 5.1, 5.2, and 5.3 of Regulation 854 under the Occupational Health and Safety Act cover the important requirements.


Throughout 2014 and the early part of 2015, the Ministry of Labour, Training and Skills Development led the Mining Health, Safety and Prevention Review (i.e. the review) to develop a better understanding of the occupational health and safety needs of the mining sector.

As part of the review, in June 2014, the ministry led a session in which labour and management participants were asked to formally rank common health and safety hazards in underground mining.  The participants assigned a level of risk to each hazard. Over 260 hazards were then ranked, and this ranking was subsequently used to decide which hazards would be analyzed in more detail in subsequent stages of the review.

Of the 18 recommendations that were set out in the final report from the Mining Health, Safety and Prevention Review, the following relate most directly to risk assessment and risk management:

Recommendation 1.1 - The Ministry of Labour, Training and Skills Development, supported by all relevant health and safety system partners and subject matter experts, to undertake a Mining Sector risk assessment with employers and labour every three years.

Recommendation 1.2 - The Ministry of Labour, Training and Skills Development to require employers in the mining sector to conduct risk assessments, which would include measures and procedures to control the risks identified in the assessment as likely to expose a worker to injury and illness. The joint health and safety committee, health and safety representative, union or workers, be consulted on the risk assessment. Employer risk assessments are to be done as often as necessary to ensure programs that result from the assessment continue to protect workers.

Background information

It is generally accepted that mining sector workplaces that use formal, risk-based approaches to identify, rank and manage workplace health and safety hazards benefit in a number of ways, including the following:

  • By working with a cross-section of workplace parties when identifying and risk-ranking health and safety hazards (and potential hazards), these workplaces obtain a shared and collective “buy-in” on the identification of priority hazards and on the selection of appropriate controls, which are ways of mitigating the risk associated with a hazard.
  • By having a common and collectively accepted understanding of what the highest risk health and safety hazards are, workplace parties can focus their efforts on responding to high priority hazards.
  • By utilizing risk-based approaches towards advancing workplace health and safety, each workplace will become more reliant on quality data regarding workplace health and safety performance, and will therefore be compelled to improve the way in which it collects, manages and analyzes data related to conventional health and safety metrics. 
  • By requiring workplaces to adopt and apply a risk-based approach, they will be in a better position to more effectively and efficiently control the highest risk workplace hazards. A deliberate, concerted and collective effort by all workplace parties to focus on controlling what are agreed upon and accepted to be the highest risk hazards in that workplace will have a significant impact on reducing the level of risk associated with those hazards.

These risk-based approaches often use particular key terms and concepts, such as risk, hazard, events and controls. Risk assessment involves the assigning of a level of risk to each of the common health and safety hazards at a workplace, followed by the ranking of those hazards. A hazard is any source of potential damage, harm or adverse health effects on something or someone under certain conditions at work.  Risk is generally considered to be the chance of something happening that will have an impact on objectives. It is usually measured in terms of event likelihood and consequences. Risks can be inherent or residual. When such conditions or situations do actually materialize in such a way as to jeopardize the health and safety of workers, they are known as events.

Once identified, workplaces need to determine the appropriate controls to prevent or mitigate the risk associated with a hazard. Controls can be activities, procedures, physical equipment or objects, or systems. Controls are sometimes described as preventing (i.e. reducing the likelihood that an unwanted event will occur) and mitigating (i.e. reducing or eliminating the consequences of an unwanted event), and as critical or non-critical. Workplaces wanting to learn more about these concepts can refer to the resources listed at the end of this guideline.

Risk assessment

The following are steps within a suggested framework that will assist workplace parties to demonstrate compliance with their regulatory obligations regarding risk assessments:

  • Identify all of the health and safety hazards (and potential hazards) for the mine or mining plant in question.
  • Take into consideration the nature of the workplace, the type of work, the conditions of work at the workplace and the conditions of work common at similar workplaces.
  • The determination of which hazards are to be risk-ranked should be decided jointly by the employer and the joint health and safety committee or health and safety representative, if any (i.e. similar to the process for determining non-routine hazardous tasks as required by Section 62.1 of Regulation 854).
  • Assign a level of risk to each hazard and rank the hazards according to their level of risk.
  • Identify the priority (i.e. highest ranking hazards) for a root-cause analysis, which is a systematic process for identifying factors and causal relationships that contribute to a problem or undesirable event. This helps define effective controls for the identified root causes.
  • Compare the priority hazards for the mine or mining plant in question to those identified for the mining sector more broadly through the ministry’s most recent risk ranking assessment, in order to understand and confirm that all hazards have been considered.

The identification of all health and safety hazards (and potential hazards) at a mine or mining plant should involve compiling all sources of potential harm, injury or adverse health effects to workers that exist at that workplace. In establishing a comprehensive list of hazards, all processes and work activities that occur or are about to occur should be considered.

Once a complete list of health and safety hazards has been established for a mine or mining plant, a level of risk needs to be assigned to each hazard on the list. A common and accepted practice for achieving this involves the use of a standard ‘likelihood versus consequence’ risk matrix (i.e. as shown in the sample risk matrix below), in conjunction with a set of graduated descriptors that characterize the full spectrum of likelihood and consequence possibilities (i.e. as shown in Table 1 and Table 2, respectively). ‘Likelihood’ is commonly understood to be the measurement of how often an event might occur, while ‘consequence’ is the outcome of an event expressed quantitatively in terms of a loss, injury disadvantage or lost opportunity.

For each adverse event or undesirable hazard exposure identified, an estimate should be made as to its likelihood of occurrence and the severity of consequence if the event were to occur, by selecting the most appropriate descriptors from Table 1 and Table 2. Once the likelihood and consequence of each event has been determined, its level of risk can be determined through the risk matrix. Once a level of risk has been assigned to each event, they can be ranked according to descending level of risk.

The risk level shown in each box in the risk matrix is determined by multiplying the value for the likelihood rating by the value for the consequence rating corresponding to any given box in the matrix. For example, the risk level of 25 shown in the box in the upper right-hand corner of the matrix is derived by multiplying the corresponding likelihood value (i.e. 5) by the corresponding consequence value (i.e. 5) for that box. 

  • ‘Critical’ risk is a risk level between 20 and 25
  • ‘High’ risk is a risk level between 12 and 16
  • ‘Moderate’ risk is a risk level between 5 and 10
  • ‘Low’ risk is a risk level between 1 and 4

Risk matrix – Likelihood versus consequence

Likelihood versus consequenceLow consequence
(rating: 1)
Minor consequence
(rating: 2)
Moderate consequence
(rating: 3)
Major consequence
(rating: 4)
Extreme consequence
(rating: 5)
Almost certain
(rating: 5)
Very likely
(rating: 4)
(rating: 3)
(rating: 2)
(rating: 1)

Table 1 - Likelihood descriptors

Almost certain5Unwanted event is almost certain to happen in the next year
(a 90% or greater chance of occurrence)
Very likely4High probability for unwanted event to occur next year
(a 50% – 90% chance of occurrence)
Likely3It is possible for unwanted event to occur next year
(between 20% - 50% chance of occurrence)
Unlikely2Low probability for unwanted event to occur next year
(between 5% - 20% chance of occurrence)
Rare1Very low probability for unwanted event to occur next year
(a less than 5% chance of occurrence)

Table 2 - Consequence descriptors

Extreme5Fatality or permanent disability
extreme impact/importance
Major4Serious event: critical injury or critical illness
major impact/importance
Moderate3Temporary disability: lost time injury or illness
moderate impact/importance
Minor2First aid treatment: no lost time
minor impact/importance
Low1No injury or illness
negligible impact/importance

Through the risk ranking of all of the health and safety hazards specified for a mine or a mining plant, it is possible to identify the priority hazards that could evolve into events in a number of different ways. The most acceptable methods for identifying priority hazards are as follows:

  • Any hazard that could result in an event that has been assigned a critical level of risk should be considered to be a priority hazard.
  • If no hazards that could result in events have been identified as having a critical level of risk, then those hazards that are in the top-ranking risk events (i.e. at least the top five) should be considered as priority hazards.
  • Hazards that have resulted in fatalities at the mine or mining plant in the past should be considered as priority hazards.

Once the priority health and safety hazards for a mine or mining plant have been identified, they should be compared to those hazards that have been identified as being priorities in the ministry’s latest risk ranking assessment for the mining sector. This exercise, which the ministry intends to repeat every three years, will enable Ontario mines and mining plants to:

  • realize how their workplace compares to similar workplaces in the province with respect to priority hazards, and if necessary, investigate any discrepancies to understand why they exist; and
  • re-evaluate the workplace’s risk assessment process, if necessary, to incorporate relevant hazards that were not captured originally.

Risk management

As per subsection 5.1(1), the purpose of the risk assessment is to identify, assess and manage hazards, and potential hazards.  Once hazards have been identified and assessed, risk management involves the ongoing monitoring and adjustment of controls that have been adopted for mitigating the risk associated with a health and safety hazard.  Some of the common categories of controls are as follows:

  • elimination, substitution or reduction
  • engineering controls
  • work practices
  • industrial hygiene practices
  • administrative controls
  • personal protective equipment

Elimination controls may be the preferred type of control, provided that it can be confirmed that the elimination of a hazard does not result in the introduction of a new, higher risk hazard.  Substitution or reduction may be appropriate where pieces of equipment or work processes which have high-risk hazards associated with them can be replaced with alternative equipment or processes which eliminate or reduce the risk of the hazards in question. Such controls are best identified at the design stage for a process or a piece of equipment. Examples of such controls may include a change in mining method to eliminate the risk of a specific type of ground failure mechanism, or a change in mobile equipment type to eliminate or reduce the risk of harmful emissions. It must be noted that substitution of a new process, equipment, or technology may result in new risks that may require further evaluation. 

Engineering controls are those that are enacted automatically and do not require human intervention to put in place. They are therefore generally more reliable than those types of controls that depend upon human involvement to function. They are effective because they isolate personnel from sources of harmful energy. Examples of such controls may include machine guarding mechanisms, ground support systems and fall prevention systems.

Work practice controls are those that rely on the skills, knowledge and experience of people, and are therefore generally not as reliable as elimination, substitution or engineering controls. Examples of such controls may include work methods and procedures, personnel selection, training, supervision and work scheduling.

Industrial hygiene practice controls are those that may limit worker exposure to health hazards including toxic chemicals, biological hazards, and harmful physical agents. Examples of such controls may include air quality monitoring, dust suppression systems and medical surveillance programs.

Like work practice controls, administrative controls are those that rely on the skills, knowledge and experience of people. In addition to health and safety legislation or regulations, examples of other administrative controls may include a particular workplace’s health and safety policies, programs or procedures, warning labels or management of change systems. 

Personal protective equipment (PPE) controls are those that provide some protection for the body against hazards. These controls are generally thought to be the least effective type for mitigating the risks associated with workplace health and safety hazards. The effectiveness of these types of controls depends on the proper identification of the equipment needed, ensuring that personnel are properly trained on its use and ensuring that it is well maintained. Examples of such controls may include hard hats, safety glasses, dust masks, high visibility safety apparel, hearing protection and protective foot wear.

The following are steps within a suggested framework that will assist workplace parties towards demonstrating compliance with their regulatory obligations regarding risk management:

  • For each of the priority hazards, conduct a root-cause analysis through which the mitigating controls for each hazard will be clearly identified.
  • Manage each of the priority hazards through continuous monitoring (and refinement, if necessary) of its identified controls.

Many types of root-cause analyses are available. Examples of common root-cause analysis methods utilized in the Ontario mining sector are the:

  • bow-tie analysis
  • failure mode and effects analysis
  • fault tree analysis
  • fish bone (i.e. the Ishikawa) analysis
  • pareto analysis

Once the necessary controls for a mine or mining plant have been formally identified for each priority health and safety hazard, the workplace should specify:

  • how each control is to be managed and monitored;
  • the criteria that will be adopted for each control to determine when it is no longer effective and needs to be improved or replaced.

It is recommended that workplaces develop and maintain documentation or records that include, at minimum, the findings of their risk assessment, the risk management initiatives that they have undertaken or will undertake, and any relevant dates.

The role of workplace parties in risk assessment and risk management

It is the responsibility of each employer to ensure that regulatory requirements for risk assessment and risk management are met. The regulation requires that the employer provide the written results of the risk assessment to the joint health and safety committee or health and safety representative, if any. It also requires the employer to consult with the committee or the representative to develop and maintain measures to eliminate where practicable, or to control where the elimination is impracticable, the hazards and potential hazards identified in a risk assessment.

It is important to note that committee members or representatives can be involved in other stages of the process and that other workplace parties can also have roles within this process, either through direct participation or subsequent consultation endorsement.

Employers of mines and mining plants should ensure that the right expertise is relied upon when conducting risk assessment and management. For example, when conducting the workplace risk assessment, employers should engage with the appropriate subject-matter experts when identifying and ranking hazards.  When doing root-cause analysis of the risk of an undesirable event, employers should also consult with those people who have skill sets and experience that are needed to deal with the health and safety hazards for the event being analyzed. These subject-matter experts can be internal to the workplace (i.e. committee members or health and safety representatives, workers or supervisors, other workplaces with specific knowledge, experience and expertise) or external to the workplace (i.e. consultants or professionals) as may be appropriate in the circumstances.

Joint health and safety committee consultation

Subsection 5.2(1) requires an employer to consult with the joint health and safety committee or the health and safety representative, if any, to develop and maintain measures to eliminate or control hazards (and potential hazards) identified as part of the risk assessment.  Where the Occupational Health and Safety Act or its regulations require that an action be taken in consultation with another party, including but not limited to the committee or representative, the Ministry of Labour, Training and Skills Development expects that the employer will engage in a meaningful interaction (i.e. including but not limited to dialogue, discussion and providing all relevant information) with the committee or representative.

There should be a genuine opportunity for the committee or representative to comment, and those comments should be received and considered in good faith. This includes taking into account any feedback and responses from the committee or representative before taking action (i.e. implementing a plan, or program) and responding to any recommendation arising out of the consultation.

Consultation is not simply informing the committee or the representative that the employer intends to take action.

Frequency of review

The risk assessment must be reviewed as often as necessary and at least annually, as per subsection 5.3(1).  This is to ensure that new hazards, or existing hazards that may have changed during the intervening period, are addressed, and that the controls that have been adopted to mitigate workplace risks continue to remain effective. Often, changes can occur to a workplace itself, or to the processes and work practices that are applied within it due to, for example, the introduction of new technology. These changes may result in new or modified hazards or they can affect existing controls.  Periodic and regular reviews are important to ensure a workplace’s risk assessment and management system continues to effectively mitigate workplace hazards and their associated risks.

This resource does not replace the Occupational Health and Safety Act (OHSA) and its regulations and should not be used as or considered legal advice. Health and safety inspectors apply and enforce these laws based on the facts they find in the workplace.