Copyright Resources Safety,Department of Mines and Petroleum Fibrous minerals and dust – managing the risks Part 1 Dust and mineral fibre exposure

Please read this before using presentation This presentation is based on content presented at the Exploration Safety Roadshow held in December 2010 It is made available for non-commercial use (e.g. toolbox meetings) subject to the condition that the PowerPoint file is not altered without permission from Resources Safety Supporting resources, such as brochures and posters, are available from Resources Safety For resources, information or clarification, please contact: RSDComms@dmp.wa.gov.au or visit www.dmp.wa.gov.au/ResourcesSafety

Copyright Resources Safety,Department of Mines and Petroleum Dust emissions from drilling operations may contain some very hazardous material These may include nickel, mercury, lead, manganese and carcinogens such as quartz and certain types of mineral fibres Dust composition is often unpredictable and health effects from exposure can be delayed Chris White will discuss drilling and dust from an OH perspective I will focus on mineral fibres and why we should be concerned about them

Copyright Resources Safety,Department of Mines and Petroleum Why mineral fibres? Rising demand for State’s minerals so some previously uneconomic orebodies containing fibrous minerals are now commercially viable Increased probability of encountering fibrous minerals as depths of exploration and mining increase All airborne fibrous minerals have some health implications Fibrous minerals have always been around. Why should mineral fibres be on our radar when doing risk assessments? Increased opportunity to encounter fibres either because of the ore type or simply the amount of ground being accessed. It’s important to be aware that all mineral fibres may be harmful, not just those that we hear about most often, such as asbestos.

Copyright Resources Safety,Department of Mines and Petroleum Recent release Guideline - Management of fibrous minerals in Western Australian mining operations Help mining industry understand hazards Risk-based approach Fibrous minerals management plan Recent release “Management of fibrous minerals in Western Australian operations” Replaces asbestos publications Greater emphasis on a risk based approach - recommendation for a Fibrous Minerals Management Plan Employers’ duty to ensure exposure of workers to airborne fibrous minerals within regulatory standards, and workers’ rights to know about workplace hazards, access to information and training outlined in guidelines?

Copyright Resources Safety,Department of Mines and Petroleum Mineral fibre types Asbestos “Asbestiform minerals” Erionite Winchite Brucite Rickterite Pyrolusite Many others

Asbestiform and non-asbestiform minerals Copyright Resources Safety,Department of Mines and Petroleum Asbestiform and non-asbestiform minerals Asbestiform riebeckite Non-asbestiform riebeckite

Copyright Resources Safety,Department of Mines and Petroleum Types of asbestos

Asbestiform fibre types Copyright Resources Safety,Department of Mines and Petroleum Asbestiform fibre types Crocidolite (Amphibole) Chrysotile (Serpentine)

Copyright Resources Safety,Department of Mines and Petroleum Origins of asbestos Parent rock is mafic or ultramafic (igneous) Disturbance in rock formation (e.g. faulting, slippage) Heat, pressure, water and minerals from parent rock lead to asbestos crystal formation Often occurs in “lenses” or bands (mm – cm) Mineral deposits with asbestos present include iron ore, nickel sulphides

Asbestos minerals probability Copyright Resources Safety,Department of Mines and Petroleum Asbestos minerals probability This is a very general map and really just illustrates that understanding the geology of the area is important so you are aware of what minerals might be encountered.

Pros and cons of asbestos Copyright Resources Safety,Department of Mines and Petroleum Pros and cons of asbestos Useful properties Fibrous morphology Durable High tensile strength, flexible Heat and corrosion resistant Low electrical conductivity Detrimental aspects Health implications from inhalation of airborne fibres

Why are mineral fibres hazardous? Airborne and respirable size (low micron) Morphology (long and thin) Persistence in the lung (insolubility of fibres and macrophages) Interaction of fibres with lung tissue to induce free radical formation

Respiratory system – particle size

Alveolar region of lung

Copyright Resources Safety,Department of Mines and Petroleum Health effects Asbestosis Lung cancer Mesothelioma Plural plaques Type of asbestos inhaled is important factor in determining which lung disease may develop crocidolite (blue) > amosite (brown) > other amphiboles >> chrysotile (white)

Exposure to asbestos fibre Typical non-occupational exposure is 0.0001 fibres/mL National exposure standard (TWA) is 0.1 fibres/mL (any form of asbestos) Humans breathe 10 to 20 m3 of air per day 10 m3 of air = 1,000 respirable fibres breathed per day About 25,000,000 fibres inhaled in a lifetime

NOHSC:3003 (2005) Membrane Filter Method Light microscopy Exposure measurement NOHSC:3003 (2005) Membrane Filter Method MSIR 9.13 1b (iv) and 9.33 (2) Light microscopy Electron microscopy (SEM, TEM) Direct reading instruments

Respirable fibre definition Copyright Resources Safety,Department of Mines and Petroleum Respirable fibre definition Widely used definition < 3 µm diameter > 5 µm long > 3:1 aspect ratio Mining definition in WA [MSIR 9.33 (3)] Maximum width  1 µm Length > 5 µm > 5:1 aspect ratio Fibre = morphology (not mineralogy) Does mineralogy matter with respect to fibre counting No! A countable fibre is defined by morphology not mineralogy.

Copyright Resources Safety,Department of Mines and Petroleum Controls If you control the dust then you control fibre emission RC dry drilling RC wet drilling Control dust = control fibre emission

Copyright Resources Safety,Department of Mines and Petroleum Any questions? For further information please contact: Dave Fleming  dave.fleming@dmp.wa.gov.au  9358 8551