A Pain in the neck

A practical guide to preventing injuries on the mine site – from the NSW Mine Safety Advisory Council

WHAT IS A MUSCULOSKELETAL DISORDER (MSD)?

MSD is an umbrella term for injuries and disorders that include:

• Sprains and strains of muscles, ligaments and tendons (eg shoulder muscle strain leading to rotator cuff tear)
• Back injuries, including damage to the muscles, tendons, ligaments, spinal discs (eg ruptured discs), nerves (eg sciatica), joints and bones
• Joint injuries or degeneration, including injuries to the shoulder, elbow, wrist, hip, knee, ankle, hands and feet
• Bone injuries (eg fractures)
• Nerve injuries (eg carpal tunnel syndrome of the wrist)
• Soft tissue hernias (eg abdominal hernias)
• Muscular and vascular disorders as a result of hand/arm vibration (HAV).

MSDs can happen suddenly or develop over time. MSDs may:

• Occur suddenly as a result of a single forceful action like pulling a moving object, lifting a heavy object, actions causing overexertion or through a slip, trip or fall.
• Develop over a longer period as symptoms associated with minor tissue injuries (including nerve and vascular tissues) are ignored, eventually resulting in a more serious injury, injuries suffered by workers (eg transport drivers, mechanics) doing repetitive work and/or work of a similar nature could also fall into this category.

KEY RISK FACTORS AND SPECIFIC TASK CHARACTERISTICS THAT INCREASE THE RISK OF MSDs
Many factors contribute to MSDs. Based on research conducted in Australia and overseas, the key MSDs risk factors in a mining/extractives environment are:

• Awkward postures
• Bending and twisting
• Manual handling/load
• Forceful exertions
• Repetitive actions
• Duration of tasks
• Heavy lifting
• Vibration – hand/arm and whole body (including jolting and jarring)
• Access
• Slips, trips and falls
• Working long hours without opportunity for rest and recovery
• Exerting force in a static position for extended periods
• Problems with the work environment (eg working in hot or cold weather, rain and unpredictable conditions)
• High job demands and time pressure
• Fatigue
• Lack of job rotation and equipment change.

RELATED MINING RISK FACTORS

Mining workplaces have their own contributing risk factors. MSDs are strongly linked to known contributing risk factors or hazards in the mining workplace, including:

• Workplace, equipment and vehicle (or cab) design
• The mine working environment factors; including the state of the decline and haul roads, uneven, muddy and wet ground, limited access underground and around equipment, poor visibility etc.
• The characteristics and locations of tools and other equipment
• Work organisation, planning and systems or work, including rosters, shutdown deadlines and overtime.

These contributing risk factors lead to, or cause, the direct risk factors in mining listed above.

OTHER ISSUES TO CONSIDER

Jobs need to suit individual workers not a notional average worker. Mining and extractive sectors now have a more diverse workforce with increased numbers of women, older workers and workers new to the industry.

Jobs and tasks need to accommodate the physical characteristics, skills and experience of individual workers rather than just a notional average worker. For example:

• Individuals will vary in the amount of force they can apply
• Some tasks promote awkward postures clue to workers’ physical size differences
• Less experienced workers may perform repetitive tasks more frequently clue to errors, or if they are unfamiliar with the task
• Lack of rotation and equipment change
• Systemic organisation problems limiting rest periods at work, rest periods outside of work and appropriate intervals of rest periods at work.

MSD – THE MOST COMMON WORKERS COMPENSATION CLAIM

From an analysis of workers compensation claim data:

• MSD from mechanical vibration, muscular stress and falls on the same level contribute approximately 50% of all claims from the WorkCover NSW data, and just over 46% of all claims from Coal Services Ltd
• Between 2002 and 2006 the two most common categories of injury in coal were other muscular stress and falls on the same level
• Metalliferous and extractives have a smaller percentage or musculoskeletal claims than coal mining (40% compared to 52%)
• There is a much higher proportion of vibration-related musculoskeletal claims in coal mining, while metalliferous/extractives have a much higher proportion of repetitive movement-related claims
• The five year claim costs for metalliferous/ quarrying are much higher than for coal ($26 million compared to $17 million), however: * the average cost of claims is much lower in the metalliferous/extractives sector ($8,000 per claim compared with $13,000 per claim in coal) * coal has a lower average time lost per claim (2.3 weeks versus 3.5 weeks) but a higher proportion of claims extending beyond 4 weeks (18% versus 15% in the non-coal sector).

CONTROLLING RISK FOR MUSCULOSKELETAL DISORDERS PREVENTING MSDs
Preventing MSDs must be part of the OHS management system. MSDs need to be managed as an integral part of each organisation’s OHS management strategy and system.

The following steps need to be undertaken in consultation with those doing the work. Prevention is based on:

• clear objectives
• management support
• resources
• expert advice
• action plans

A STRATEGIC APPROACH:

1. Set your broad objectives depending on the needs of your enterprise, your objectives could relate to legislative compliance, reducing the costs of workers compensation or MSD incidents, improving productivity, operational efficiency or a combination of these and other factors.
2. Appoint a management champion and a representative team to manage the process – this allocates responsibility for getting the job clone and establishes a participative approach.
3. Allocate resources (including a budget)
4. Consider the need for expert help and training of key personnel – MSDs are complex and multi-factorial, occupational diseases often requiring specialised understanding.
5. Develop and implement an action plan including timeframes, targets and key performance indicators for MSD performance.

“Between 2002 and 2006 the two most common categories of injury in coal were other muscular stress and falls on the same level.”

For many companies initial action will include:

• Conduct a stocktake of what has been clone/what is being clone about MSD prevention and assess its effectiveness.
• Review the OFIS management system to ensure that it effectively integrates MSD prevention – in particular assess whether the current OFIS policy needs a specific target or priority statement related to the control of MSD hazards and responsibility for MSD management and performance has been allocated.
• Determine whether the risk management process for MSDs meets legislative requirements.

POSITIVE HELP – PARTICIPATORY ERGONOMICS
FINDING EFFECTIVE RISK SOLUTIONS: UNITING WORKERS EXPERIENCE WITH INPUT FROM ERGONOMISTS

Participatory ergonomics involves workers being helped by an ergonomist, or those with ergonomic skills, to identify and manage ergonomic hazards. This approach differs from having an ergonomist ‘independently’ undertake a consultancy and develop solutions. Participatory ergonomics also differs from risk assessment of ergonomic hazards without involving someone with expertise in ergonomic hazards and knowledge of appropriate ergonomic controls. Wilson (1995) in his chapter on Ergonomics and Participation (p.1075) states,

“…as well as an ergonomics management programme and training and awareness for as many as possible in the company, participative ergonomics also requires the active involvement of relevant job holders in task, job and workplace assessments and in the generation and testing of alternative solutions.”

There have been several reviews of the effectiveness of participatory ergonomics (Cole et al, 2005, Rivlis et al, 2008) and participatory ergonomics is strongly supported worldwide and promoted by most jurisdictions.

Examples of the participatory ergonomics approach in the mining industry include the Badger Mining project referred to in Torma-Krajewski et al (2006), the work by Robin Burgess-Limerick et al (2004), and the Ergonomics Task Force currently in place at Crinum Mine in Queensland. continuously. Examples include the use of hand tools in maintenance and handling of bolting equipment in bolting operations.

DIRECT RISK FACTORS
AWKWARD POSTURE

Awkward postures are common in mining and extractives clue to the nature of the work environment, the equipment used and the confined areas where tasks are performed.

FORCE

Applying force, especially for body areas including the low back, shoulders, wrists and hands, is strongly linked to MSD. Force on the low back is common in manual handling of loads. Manual task hazards in mining are worsened clue to significant work design factors, including lack of adequate lighting, wet and/or muddy and unstable ground conditions, and limited or restricted space to move.

Manual tasks (forceful exertions), combined with other risk factors, such as awkward posture or vibration, will significantly increase the risk. Some excess forces to the hands and wrists are found when using hand tools, gripping objects, or loosening tight parts.

• Manual Handling: MSD of the back, shoulder, arms, knees and neck also need to be considered as a minimum. Manual task hazards are compounded by significant environmental factors underground, including lack of adequate lighting, wet, muddy and/or unstable ground conditions, and limited or restricted space.
• Difficult loads: An additional characteristic of hazardous manual tasks is where the load is unstable, unbalanced or difficult to grasp or hold.

REPETITION AND DURATION

Repetition exposure occurs when similar movements are required to be performed for one hour or more. This includes situations where similar actions are performed across a number of tasks during a shift and the same muscles and other soft tissue are being used continuously. Examples include the use of hand tools in maintenance and handling of bolting equipment in bolting operations.

Duration is the length of time a task is performed. The longer the task is performed the higher the risk. Extended shifts should be taken into account for duration. Operating mining vehicles in open cut mining is one of the most obvious tasks where duration is a factor.

VIBRATION

Three categories of vibration should be considered:

• Whole body vibration – steady state
• Whole body vibration – jolts and jars (transient mechanical shock)
• Hand/arm vibration

CONTRIBUTING RISK FACTORS
LOOK BEHIND DIRECT RISK FACTORS TO FIND CONTRIBUTING CAUSES

To assess and control MSD risk factors it is important to find out why direct factors (ie. those directly linked to a possible MSD outcome) are present. These are the contributing risk factors.

For example, the contributing risk factor or root cause for the risks associated with shovelling coal off walkways is most likely the design of the system causing coal spillage. Other contributing risk factors will be related to the nature of equipment or work environment, eg. mesh walkways require shovelling to clear the coal but a different design, eg specially design checker plate, could be hosed to clear the coal.

Another example of contributing risk factors includes awkward postures in underground mining caused by the work environment or the nature of the load or equipment. In mining and extractives direct risk factors will generally be due to contributing:

• Organisational factors including systems of work and work practices
• Nature and design of equipment and loads
• Work environment issues.

However, it is important to look for other less obvious contributing risk factors in the risk assessment. The full list of contributing risk factors can be found in the National Code of Practice (2007): http://www.safeworkaustralia.gov.au/swa/HealthSafety/HazardSafetyIssues/ManualTasks.htm

THE WORK ENVIRONMENT

The physical work area design and layout can significantly affect the way work is done, particularly in underground mining where uneven work surfaces and obstructions related to limited housekeeping are common. There are also equipment interaction issues in the work area and the equipment itself creating MSD risks. The interaction of workers and mining work environment cause direct risk factors of:

• Sustained exertion of force
• Sustained awkward posture
• Slips, trips and falls
• Repetitive reaching, bending or twisting
• Increased frequency of tasks.

Uneven surfaces, poorly designed steps, ramps and contaminants on working surfaces can lead to:

• Slippery and uneven working surfaces that may increase the exertion required to perform manual tasks, as well as create a slip or trip hazard when undertaking a manual task
• Difficulty maintaining balance and increased friction when moving objects
• Awkward postures due to the need to see the stairs or ramps while handling a load and ascending/descending.

Obstructions related to inadequate housekeeping and cleaning can lead to:

• Awkward postures such as reaching or bending over obstacles
• Slips, trips and falls to avoid the obstruction
• Awkward postures such as side bending to see path of travel and avoid obstructions
• Increased forceful exertion due to the stop/start nature of moving objects around the obstacles.

Difficult lighting conditions may lead to awkward or sustained postures, such as leaning backwards or forward to improve viewing or avoid glare, reflection and excessive light. Some instances in mining and extractives include glare from the sun when operating vehicles, glare from lights at night and insufficient lighting underground for highly visual or technical tasks.

ORGANISATIONAL FACTORS, INCLUDING SYSTEMS OF WORK AND WORK PRACTICES

In large mining organisations most planning, purchasing and design decisions are made external to the mining workforce doing the work. These decisions impact on the way work is organised or the way procedures are designed and applied. Some organisational factors may result in manual tasks being performed in a way which affects the musculoskeletal system. For example:

• Production and time pressures may increase the frequency at which repetitive tasks are performed or introduce a risk of slips, trips and falls.
• Under-resourcing of workers may increase the duration of risk exposure.
• Overtime and inadequate scheduling may reduce recovery time between tasks.
• Maintenance tasks may need to be performed in the field, increasing the amount of force required because of lack of equipment.

THERMAL WORK ENVIRONMENT

Workers may be exposed to a variety of thermal environments in mining and extractives leading to:

• Increased grip force due to reduced sensitivity in the hands in cold environments or difficulty grasping due to hand perspiration in hot environments.
• Sudden high force due to loads slipping from the hand.
• Sustained forceful exertion to maintain grip.

NATURE AND DESIGN OF EQUIPMENT, TOOLS AND LOADS

Mining uses equipment, tools and loads best suited for the production environment and material being mined. In some sectors, for example underground coal, some equipment design and tools have not greatly changed in the past decade. With advances in technology it is possible to review the match between the equipment and the workers to determine if a better fit is possible. The key factors to review are:

• Poorly designed or inadequate plant causing more frequent repetitive tasks and awkward postures.
• Inadequate seating causing poor posture or increased whole body vibration.
• Poor design of access points on plant causing increased likelihood of slips, trips and falls.
• Poorly designed or inadequate hand tools causing increased forces and exposure to hand/arm vibration.
• Bulky, awkward and poorly designed loads leading to high, sudden or unexpected forces when handling them.

RISK FACTORS FOR RISK ASSESSMENT OF MANUAL TASKS AND SLIPS, TRIPS AND FALLS RISK
DIRECT RISK FACTORS:

• Awkward postures
• Force (including manual tasks and high, jerky, unexpected forces)
• Repetition of movements and duration of the task
• Vibration – whole body, hand/arm and jolting/jarring

CONTRIBUTING RISK FACTORS:

• Organisational factors including systems of work and work practices
• Nature and design of equipment and loads
• Work environment

OTHER FACTORS:

• Tasks designed for average workers.

OTHER RISK FACTORS
AGEING WORKFORCE

The main issues for older workers are their ability to undertake physically demanding or physiologically demanding work. Strength and endurance of legs, then trunk, then shoulders, decline with age (Parker 2005). Tasks which older, injured miners rate as significantly more physically demanding than older, injury-free miners include:

• manual tasks (lifting, carrying, lowering)
• pushing, pulling, dragging (eg cables,hoses, other loads)
• reaching forward, bending, twisting, stooping
• prolonged work in an awkward or uncomfortable posture
• shovelling
• repetitive physical work

Older workers present an increased risk of slips, trips and falls. Factors relate to loss of balance and the lack of ability to recover from a slip. Specific risks include:

• effects of ageing on vision (older workers have more difficulty in noting trip hazards unless illumination and contrast is increased)
• loss of strength and endurance in the lower legs
• changes to sensory and motor function affecting balance
• potential cumulative effects of injuries over time.

Older workers will often have more falls than younger workers and have a more severe injury outcome.

NEW WORKERS

New workers in any hazardous job have an elevated risk of injury.

• Are new workers likely to rush to volunteer or assist in tasks they are not familiar with?
• Do they understand the need to pace themselves with some of the physically demanding tasks?
• Are they aware of the MSD hazards – working beyond their physical capacity for prolonged periods?
• Are they given the jobs no one else wants?
• Do they know exactly what to do and how?
• Will they ask for assistance?

SLIPS, TRIPS AND FALLS RISK FACTORS

In the mining and extractives industry, the hostile environmental conditions and regular interaction with plant and equipment are major risk factors contributing to slips, trips and falls. Specific risk factors include:

• Work at night or underground (limited visibility)
• Work in, on and around uneven and hazardous ground conditions
• Poor access to heavy vehicles for operators and maintainers

Risk factors in underground mines include:

• Very low levels of lighting
• Wet, boggy, muddy and uneven ground conditions
• Restrictions in interacting with equipment and objects due to seam conditions, mine plan and ground conditions
• Dirt and mud obscuring visual features of steps and platforms
• Dirt and mud clogging footwear treads
• Wet conditions restricting choices of footwear
• Frequent changes in conditions due to shift and mine life.

VIBRATION
WHOLE BODY VIBRATION

Information is available for the mining and extractives industry on managing the risk of whole body vibration (WBV) in the publication Bad Vibrations. Although the information in Bad Vibrations is predominantly for the coal sector, metalliferous mines and extractives will find it useful.

Equipment operators are exposed to WBV in both sitting (most equipment operation in mining and extractives) and standing (eg. jumbo operators in underground metalliferous) operations. Common operational groups include drivers, operators and passengers in a variety of vehicles such as bulldozers, dump or haul trucks, graders loaders, personnel and equipment transport and load/ haul/dump (LHD) machines used in surface and underground operations. Rides in most of these vehicles include jolts and jars, as well as steady state vibration.

THREE MAIN SOURCES OF HARMFUL VIBRATION
There are three main sources of harmful vibration in vehicles and machines:

• Rough road and poor work surface conditions
• Vehicle activity – eg. ripping versus pushing material in a dozer
• Engine vibration, but to a lesser extent.

FACTORS THAT INCREASE OR DECREASE DRIVE EXPOSER
There are many factors that can either increase or decrease the exposure for the driver. These include:

• Road construction and maintenance (grading etc)
• Vehicle type and design
• Age and condition of the vehicle
• Maintenance of vehicle suspension systems
• Seat design, suspension and maintenance
• Cab layout, design and orientation
• Vehicle or machine speed, driver skills and awareness
• Lighting and visibility
• Task design and work organisation

WBV HAZARDS NEED AN APPROPRIATE METHOD OF RISK ASSESSMENT AND CONTROL

Based on this, the hazard of WBV needs to be followed through using an appropriate method of risk assessment and controls. WBV guidance may be addressed by measuring and analysing exposure to vibration, comparison with Original Equipment Manufacturers (OEM) and ISO/ASNZ standards, equipment design and seating, training to minimise exposure.

ROAD MAINTENANCE

• Planned, systematic road maintenance programs
• Dedicated vehicles and drivers for road maintenance
• Effective communication of road conditions (eg signposting, markers)
• Prompt repair of poor road conditions.

VEHICLE & SEAT DESIGN

• Vehicle suspension appropriate for loads – no bottoming out
• Good seat design and suspension
• improved visibility from cab, especially at night (headlights)
• Forward facing passenger seating
• Fully adjustable seating.

OPERATOR TRAINING & AWARENESS

• Raise awareness of harmful effects of vibration
•  Driver competency training
• Regular breaks out of cab.

SPEED

• Enforce speed limits
• Appoint competent, safe drivers
• Speed limit vehicles in specific situations.

VEHICLE MAINTENANCE 

• Planned maintenance of vehicle and seat suspensions
• Specialist maintenance for vehicle and seating suspension systems.

MISCELLANEOUS

• Ensure adequate shot firing standards
• Equipment exposure limits
• Equipment changeout and swap arrangements.

JOLTING AND JARRING(TRANSIENT MECHANICAL SHOCK)

WBV includes exposure to high amplitude and infrequent mechanical shocks. These can appear on incident reports as jolting and jarring, seats bottoming out and workers reporting rough rides (ie jolting and jarring while a vehicle is in motion).

Although rough rides may be less common in the metalliferous underground sector this is dependent on the state of the decline, driver speed and the appropriate seat design and adjustment by workers.

HAND-ARM VIBRATION

Hand-arm vibration (HAV) is transmitted as a result of work processes or tasks to workers’ hands and arms. Common sources of HAV in mining and extractives are from:

• Hand-held power tools (used in maintenance for process plants, fixed plant,some mobile equipment)
• Hand-guided powered equipment (mainly hand-held drills, airleg drills, drill rigs)
• Powered machines where vibration is transmitted via body to hands (operating jumbos without vibration dampening).

THE MAIN HAV RISKS FACTORS TO REVIEW
THE MAIN FACTORS TO REVIEW INCLUDE:

• Length of exposure – the longer the worker is exposed to the vibration (ie uses the vibration causing equipment) the more likely a negative outcome.
• The vibration level of the equipment, usually measured in m/s². Common mining vibration levels range from a low value of 2 m/s² for some lower vibration rattleguns to close to 6 m/s² for low level rock drills (OPERC 2007). In a South African metalliferous mining evaluation rock drills had weighted vibration levels in excess of 20 m/s².

“In some sectors, for example underground coal, some equipment design and tools have not greatly changed in the past decade.”

SOURCE
MANAGING MUSCULOSKELETAL DISORDERS

This article is an extract from a publication based on a joint project between Industry & Investment NSW and the Queensland Department of Mines and Energy (DME) called “Managing musculoskeletal disorders – A practical guide to preventing musculoskeletal disorders in the NSW mining and extractives industry (2009). This plain English version is based on the technical report produced by Trudy Tilbury from DME. The New South Wales Mine Safety Advisory Council initiated this guide as part of its focus on decreasing musculoskeletal disorders in the NSW mining and extractives industry. The Mine Safety Advisory Council would like to acknowledge the Health Working Party and the Musculoskeletal Disorders Project Steering Group for overseeing the development of this guide.

DISCLAIMER

The compilation of information contained in this document relies upon material and data derived from a number of third party sources and is intended as a guide only. Use of this document does not relieve the user (or a person on whose behalf it is used) of any obligation or duty that might arise under any legislation (including the Occupational Health and Safety Act 2000, any other Act containing requirements relating to mine safety and any regulations and rules under those Acts) covering the activities to which this document has been or is to be applied. The information in this document is provided voluntarily and for information purposes only. The New South Wales Government does not guarantee that the information is complete, current or correct and accepts no responsibility for unsuitable or inaccurate material that may be encountered.