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Fibrous minerals and dust – managing the risks Part 1 Dust and mineral fibre exposure.

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Presentation on theme: "Fibrous minerals and dust – managing the risks Part 1 Dust and mineral fibre exposure."— Presentation transcript:

1 Fibrous minerals and dust – managing the risks Part 1 Dust and mineral fibre exposure

2 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: or visit 2

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4 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 4

5 Recent release Guideline - Management of fibrous minerals in Western Australian mining operations  Help mining industry understand hazards  Risk-based approach  Fibrous minerals management plan 5

6 Mineral fibre types  Asbestos “Asbestiform minerals”  Erionite  Winchite  Brucite  Rickterite  Pyrolusite  Many others 6

7 Asbestiform and non-asbestiform minerals 7 Asbestiform riebeckiteNon-asbestiform riebeckite

8 Types of asbestos 8

9 Asbestiform fibre types 9 Crocidolite (Amphibole) Chrysotile (Serpentine)

10 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 10

11 Asbestos minerals probability 11

12 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 12

13 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 13

14 Respiratory system – particle size 14

15 Alveolar region of lung 15

16 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) 16

17 Exposure to asbestos fibre  Typical non-occupational exposure is fibres/mL  National exposure standard (TWA) is 0.1 fibres/mL (any form of asbestos)  Humans breathe 10 to 20 m 3 of air per day  10 m 3 of air = 1,000 respirable fibres breathed per day  About 25,000,000 fibres inhaled in a lifetime 17

18 Exposure measurement  NOHSC:3003 (2005) Membrane Filter Method MSIR b (iv) and 9.33 (2)  Light microscopy  Electron microscopy (SEM, TEM)  Direct reading instruments 18

19 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) 19

20 Controls Control dust = control fibre emission 20 RC dry drillingRC wet drilling

21 Any questions? For further information please contact: Dave Fleming  


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