fibrous minerals and dust – managing the risks part 1 dust and mineral fibre exposure

Fibrous minerals and dust – managing the risksPart 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

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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

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Recent release

Guideline - Management of fibrous minerals in Western Australian mining operations

Help mining industry understand hazardsRisk-based approachFibrous minerals management plan

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Mineral fibre types

Asbestos “Asbestiform minerals”

Erionite

Winchite

Brucite

Rickterite

Pyrolusite

Many others

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Asbestiform and non-asbestiform minerals

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Asbestiform riebeckite Non-asbestiform riebeckite

Types of asbestos

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Asbestiform fibre types

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Crocidolite(Amphibole)

Chrysotile(Serpentine)

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

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Asbestos minerals probability

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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

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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

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Respiratory system – particle size

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Alveolar region of lung

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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)

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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

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Exposure measurement

NOHSC:3003 (2005) Membrane Filter MethodMSIR 9.13 1b (iv) and 9.33 (2)

Light microscopy

Electron microscopy (SEM, TEM)

Direct reading instruments

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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)

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Controls

Control dust = control fibre emission20

RC dry drilling RC wet drilling

Any questions?

For further information please contact:

Dave Fleming

dave.fleming@dmp.wa.gov.au

9358 8551

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