In step 3 of conducting a safety assessment, operators of prescribed mines identify and adopt risk control measures for hazards that could lead to an MMH event at the mine.
What is a risk control measure
Risk control measures are actions taken to eliminate, prevent or reduce the occurrence of a hazard that you have identified.
By adopting risk control measures, you are aiming to reduce the risks to health and safety so far as is reasonably practicable.
Risk control measures must be designed so they are fit for purpose, put in place, used and maintained by employees to ensure the control measures work when required.
Example: an evacuation procedure is customised for the mine, distributed during site induction and includes scheduled alarm inspections and evacuation drills to test the procedure's effectiveness.
You must consult with affected employees
Throughout the process of identifying, documenting and adopting risk control measures you must consult with affected employees directly or via Health and Safety Representatives.
What does 'so far as is reasonably practicable' mean?
When you are adopting risk control measures section 20(2) of the OHS Act tates that you need to take the following matters into account to determine what is 'reasonably practicable':
the likelihood of the hazard or risk concerned eventuating
the degree of harm that would result if the hazard or risk eventuated
what the person concerned knows, or ought reasonably to know, about the hazard or risk and any ways of eliminating or reducing the hazard or risk
the availability and suitability of ways to eliminate or reduce the hazard or risk
the cost of eliminating or reducing the hazard or risk
Identifying risk control measures
There are many ways to come up with new risk control measures, such as via brainstorming sessions or reviewing the standards and latest technical improvements from conferences, industry associations or publications.
Regulation 405 of the OHS Regulations sets out a specific hierarchy for the measures that must be taken to control risks at a mine.
You must follow this hierarchy of control when considering and adopting risk control measures.
Using the hierarchy of control
The table below shows the levels of control specified in the Regulations and the order in which they must be considered and deployed.
Having convened the relevant experts and affected HSRs and employees, consider the various risk control measures that you could adopt, so far as is reasonably practicable, to control the hazards, which could lead to MMH events, identified at the mine. You should start with the MMH event that has the highest level of risk (as determined by your risk matrix).
Hierarchy of control
Employers must use the hierarchy of control to eliminate or reduce risks at work
Level of control
Description of control
Eliminate the risk
Mine operators must eliminate risks, so far as is reasonably practicable. Where it is not reasonably practicable to do so, you must use the following controls in order of priority, from most to least effective.
Substitute the hazard/activity
By substituting the hazard/activity with a less hazardous activity, procedure, plant, process or substance you might significantly reduce the risk to health and safety.
Isolate people from the hazard
You may be able to keep workers safe on and off-site by removing them from the identified hazard.
Use engineering controls
Engineering controls, such as an automated shutdown system may further significantly reduce the risk.
Use administrative controls
Administrative controls, such as instructing workers to follow health and safety procedures or adhere to signs, may provide a moderate level of risk reduction and are less effective controls than the proceeding ones.
Use personal protective equipment (PPE)
PPE, such as hard hats or breathing apparatus, may provide a moderate (generally the lowest) level of control.
Consider using layers of protection
In some instances a number of different controls can together provide the best reduction in risk, such as using a combination of emergency systems, safety devices, operating procedures and control systems. For example, control measures considered to minimise the impacts of rock fall may include:
geotechnical assessment during design phase
competent and trained operators
operator and technical staff inspections
installed ground support
Reviewing existing risk control measures
If you already have risk control measures in place you can review these by asking the following questions - starting with the MMH event that has the highest level of risk.
Answering these questions should highlight hazards or outcomes that require additional risk control measures to reduce the risk.
Are there preventative and mitigating control measures and/or is one type of control measure favoured (i.e. are the majority of controls mitigating)?
It is good practice to recognise whether or not mitigating controls outweigh preventative controls. If preventative controls are under-represented it is recommended further investigation be carried out to ensure all available preventive controls have been considered.
Does every cause and outcome pathway have at least one effective control measure?
It is generally recognised certain controls are deemed 'critical'. When this type of control is removed it is certain a MMH event will occur. This assists mine operators when prioritising control implementation.
Is there a range of control measure types being used and is the hierarchy of controls evident?
The aim is to implement higher order controls (i.e. top end of the hierarchy of controls) as much as possible without relying on lower order controls. This type of assessment should be routine.
Documenting risk control measures
After you identify potential controls, some may be accepted for implementation while some may be rejected and others may require further investigation before a decision can be made.
The OHS Regulations require you to document:
control measures that have been accepted for implementation and why they were accepted
control measures that have been rejected and why they were rejected
control measures you identified that require further investigation before you can reach a decision on whether to accept or reject them
You must ensure a person is made responsible for implementation or further investigation of control measures and that a due date is assigned to the completion of the investigation/s.
The requirement is to list risk control measures alongside each of the MMH events you have identified. The table below shows an approach that includes how performance can be monitored and why the control measure was adopted.
Performance monitoring method
Frequency and justification
Air blast loading and hauling ore from unsupported stopes
Use automated remotely controlled LHD face equipment
Pre start up checks, routing maintenance, equipment condition monitoring
To manufacturer's specification
Supervisory - clear areas checked before working at the face
Job production cycle check by Mine Manager
As per management audit schedule
Monitoring equipment installed
Testing and calibration
At beginning of new production cycle and annual as per manufacturer's specification
Visual approaches to documenting risk control measures
Using a bowtie risk analysis model is useful as, in the event of an emergency, it quickly communicates what risk control measures can be used to prevent and mitigate an MMH event.
Bow-tie diagrams provide a visual method to highlight gaps in MMH event scenarios where control measures may be beneficial.
Reducing the likelihood of an event can generally be achieved by focusing on preventative controls (i.e. the left side of the bow-tie) while improvements in severity can generally be achieved by focusing on the mitigating controls (i.e. the right side of the bow-tie).
Adopting risk control measures
The Regulations require mine operators to inform Health and Safety Representatives (HSRs) and affected employees about the reasons for adopting new control measures and the reasons for rejecting any alternative measures that were discussed.
You should consider how the new control measure will be supported with systems, such as procedures, training, information, supervision, maintenance, inspection, testing and auditing.