DUST CONTROL BEST PRACTICE
With an increase of cases of coal workers’ pneumoconiosis or the black lung, dust control on mine sites is on the radar of Safe Work Australia and state governments to reduce workplace exposure standards.
IN 2017, Scott Morrison famously entered parliament with a lump of coal stating “don’t be scared, it won’t hurt you, it’s coal”. But as it turns out, he was wrong.
The incurable black lung or coal workers’ pneumoconiosis has hit Queensland coal mines with a vengeance, leading to new dust control standards on mine sites.
Exposure to dust can cause irritation to the eyes, skin and respiratory tract, and prolonged exposure, breathing in coal dust, silica dust and other finely powdered materials, can lead to a range of serious lung diseases.
Workers who are exposed to respirable dust at levels that exceed the occupational exposure limit (OEL) are at risk of developing diseases including silicosis, coal workers’ pneumoconiosis (CWP), chronic obstructive pulmonary disease (COPD) and lung cancer.
Late last year the Queensland State Government committed to a respirable dust exposure level review, pending a review of workplace exposure standards for airborne contaminants including coal dust by Safe Work Australia (SWA).
As an interim measure, the Coal Mining Safety and Health Regulation 2017 (CMSHR) has been amended, building on the recommendation of the Monash review and the Parliamentary Select Committee report.
The regulated limit or maximum average concentration a worker breathes in a mine atmosphere containing respirable dust has been reduced from 3mg/m3 to 2.5mg/m3, effective from November 1, 2018.
While this is a step in the right direction for Queensland, it remains to be seen if other states follow suit.
A spokesperson from SWA said that the agency is not a workplace health and safety (WHS) nor natural resources safety regulator, and that each of the states and territories hold responsibility for compliance and enforcement of laws in their jurisdictions. “WHS in the natural resources and mining sector is regulated by states and territories,” they said
Jurisdictions regulate WHS in the sector slightly differently.”
“For example, New South Wales, South Australia and the Northern Territory have implemented the model WHS laws and enacted supplementary provisions to deal with mining safety; and in Queensland and Western Australia there are separate mining laws in addition to their primary WHS laws.”
However, occupational lung diseases are a priority condition in the Australian Work Health and Safety Strategy 2012-2022.
SWA is working on an occupational lung diseases work plan that will be implemented over 2019 and 2020, including a literature review into dust control technologies to better provide advice about the most effective control measures to protect workers from workplace dusts.
“We are also evaluating the workplace exposure standards for airborne contaminants,” the spokesperson said.
“The workplace exposure standards represent the airborne concentrations of a chemical that is not expected to cause adverse effects on the health (illness or disease) in an exposed worker who is not wearing respiratory protective equipment.
“Under the model WHS laws, a person conducting a business or undertaking at a workplace must ensure that no person at the workplace is exposed to an airborne concentration of a chemical that exceeds the exposure standard.”
The draft evaluation report for coal dust (respirable, containing less than 5pc quartz) suggested that Time Weighted Average (TWA) exposure limits of 0.9mg/m3 for respirable dust of bituminous and lignite coal and 0.4mg/ m3 for respirable dust of anthracite coal is recommended to prevent CWP, COPD and progressive massive fibrosis (PMF).
While Queensland recently revised exposure limits, the current standard coal dust concentration in the 2018 version of Workplace Exposure Standards for Airborne Contaminants is still 3mg/m3.
“The recommendations in the draft evaluation report are not mandatory values under state and territory WHS laws until they are agreed by SWA members and adopted into those laws,” the SWA spokesperson said.
“The expertise of industry and worker stakeholders and the Australian public is crucial for SWA members to make informed decisions about what values should be adopted.
“We will continue to seek feedback for each of the workplace exposure standards as they are reviewed to ensure practical considerations are taken into account.”
Controlling dust
Mining companies can reduce workers exposure by reviewing the methods and products used for dust suppression purposes — because if the impacts of dust on mining processes are controlled – so too will the exposure levels.
Australian Institute of Occupational Hygienists president Dr Julia Norris said there are some basic principles that can be applied to control dust and in fact, all workplace hazards.
“We call these principles the “hierarchy of control,” Dr Norris said.
“We like to start at the top of the hierarchy of control, because these strategies actually remove the hazard rather than just containing it.”
The first principle is elimination; this means not using materials or processes that generate dusts in the first place.
The second is substitution, which involves using alternative materials that are less hazardous than the material currently being used.
Thirdly is engineering control, involving changing the process so that less dust is not formed in the first place, or modifying equipment to prevent dust coming in to contact with workers; for instance, wet process to reduce dust or installing ventilation to capture and remove dust before it becomes a hazard.
Fourthly is administrative control such as work instructions, procedures and training, while fifth is the use of personal protective equipment (PPE), which Dr Norris said is the last line of defence if other controls are not feasible.
“While PPE does work, it relies on the correct selection, use and maintenance of each piece of equipment to give adequate protection; and in the real world environment, this is often not the case,” she said.
Dr Norris said she commended SWA on their current review of the WES.
“However, I need to reiterate that WES’s are only a tool to assess the need for controls in the workplace, they are not controls in themselves,” she said.
“It is vitally important that we educate workplaces about the correct use and interpretation of Workplace Exposure Standards.
“While the WES does define a legal upper limit, it is not a target, but rather a tool to be used to guide controls.”
Workplace exposure monitoring is just one small part of a comprehensive occupational health program.
It is important for mining operations to understand that in order to truly prevent occupational diseases, they must prevent exposure in the first place.
The AIOH and the British Occupational Hygiene Society (BOHS) have developed the Breathe Freely Australia program aimed at employers, health and safety managers and anyone responsible for occupational health programs in the workplace.
“It is about raising awareness, both of the hazards encountered and how to control them,” Dr Norris said.
For more information visit www.breathefreelyaustralia.org.au.