Department of Consumer and Employment Protection © 2005 Resources Safety 1 Please read this before...

1Department of Consumerand Employment Protection © 2005 Resources

Safety

Please read this before using presentation

This presentation is extracted from content presented at the 2005 Mines Safety Roadshow held in October 2005

It is made available for non-commercial use (eg 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:[email protected]

or visitwww.docep.wa.gov.au/ResourcesSafety

Toolbox presentation: Electrical safety in mining October 2005


Safety

Reporting of electrical accidents

Section 78 of MSIA 1994 requires:

“every electric shock or burn to a person and every dangerous occurrence involving electricity, to be immediately reported to the District Inspector and recorded in the Record Book kept at the mine”

(whether or not an injury or damage has occurred)


Safety

Investigation of electrical accidents

Regulation 5.11 of MSIR 1995 requires the appointed “Electrical Supervisor” to investigate, record in the electrical log book and report to the manager, details of every: electric shock or burn to a person fire suspected to be caused by electricity dangerous occurrence involving electricity that could have

caused injury to a person


Safety

Reportable occurrences

0 1000 2000 3000 4000 5000

Breakage of ropeRailways

Presence of gasGas or dust ignition

ExplosivesLight vehicle incidents

Unconsciousness/fumingCranes

Drill/power shovelsFixed plantRock falls

Wall failuresNot categorized

ElectricalTruck/ mobile plant

Outbreak of fire

• Electrical accidents category is ranked 3rd highest


Safety

Electric shocks incidents 1995 – 2004

134

170 170

237210 219

197 210

262

0

50

100

150

200

250

300

95-96 96-97 97-98 98-99 99-00 00-01 01-02 02-03 03-04


Safety

Electric shock incidence rates 1995 – 2004

0

100

200

300

0.0

2.0

4.0

6.0

8.0

10.0

Shocks 134 170 170 237 210 219 197 210 262

Incidence 3.62 4.16 4.00 5.87 5.41 5.47 4.80 4.92 5.72

95-96

96-97

97-98

98-99

99-00

00-01

01-02

02-03

03-04

• Incidence rate as shocks per 1,000 employees


Safety

Electric shock severity

INJURIES2%

SHOCKS98%


Safety

Factors affecting electric shock severity

Body impedance

Current path through the body

Shock current magnitude

Duration of shock

AC or DC supply


Safety

Mining electrical fatalities to October 2005

May 2002 C Harris Nickel Seekers (Daisy Milano Mine)

Mar 2001 R Griffiths Meteor Nominees (Meteor Stone Quarry)

Feb 1994 M Baljeu Westralian Sands (North Yoganup)

Mar 1991 W Gatt Poseidon (Karonie mine)

Nov 1988 JS Meharry Hamersley Iron (Dampier)

Feb 1988 M Rayner CSIRO (Exploration)

Apr 1981 AJ Woolridge Hill 50 Gold (Mount Magnet)

Nov 1981 P Tsakisirus Mt Newman Mining (Nelson Point)

Dec 1980 M D Hobart Agnew Mining (Leinster)


Safety

Machinery contact with overhead powerlines

Year Trucks Excavator Drills Cranes Misc. Incidents

1995 7 1 1 2 1 12

1996 1 1 1 2 5

1997 2 6 1 1 10

1998 4 3 2 3 12

1999 2 2 3 1 8

2000 2 2 1 1 6

2001 2 1 3

2002 3 2 2 7

2003 2 2 1 2 7

2004 4 2 2 8

Total 21 23 5 12 12 78


Safety

Review of 628 shocks in last three years

Occupation

Location

Equipment type

Circuit function

Accident causes


Safety

Electric shocks by occupation

Electrician15%

Mechanic27%

Operator41%

TA/App7%

Other10%


Safety

Electric shocks by location

U/G6%

SURFACE94%


Safety

Electric shocks by equipment type

Portable18%

Transportable22%

Mobile6%

Fixed54%


Safety

Electric shocks by circuit function

Control Circuits

16%

Pow er Circuits

84%


Safety

Electric shock causes

Static4%

Defects62%

Work Practices

34%


Safety

Electric shocks caused by equipment defects

Exposed live parts

19%

Other Faults40%

Ingress of Water41%


Safety

Electric shocks caused by work practice

Welding contacts

37%

Failure to isolate25%

Live w ork21%

Tank house contacts

17%


Safety

Opportunities for improvement (many)

Regulatory work in progress to: prohibit unnecessary “live” electrical work extend use of RCD “earth-leakage protection” require use of welding VRDs

RCD = residual current device

VRD = voltage reducing device


Safety

“Live” electrical work

Energy Safety introducing new regulations that prohibit unnecessary “live” electrical work undertaken by electricians: excludes maintenance testing no “live” work allowed in domestic premises necessary work must be demonstrated and subject to written

work procedures that will assure safety

(7% of mining electric shocks involve “live” work)


Safety

RCD - Earth-leakage protection

A 30mA RCD will automatically cut off the electricity supply in the event of an electric shock to a person before any harmful effects can occur

Only an RCD will detect water ingress into electrical equipment (41% of defects, 25% of shocks)

Regulation 5.24 of MSIR 1995 currently requires 30mA RCD protection for all portable apparatus at the mine


Safety

RCD - Earth-leakage protection cont.

18% of shocks involve portable equipment already RCD protected

16% of electric shocks involve lighting circuits that are not currently required to be RCD protected

16% of electric shocks involve control circuits that are not currently required to be RCD protected

(potential to protect against 50% of shocks)


Safety

RCD - Earth-leakage protection cont.

Proposal:

Require all new lighting circuits to be RCD protected, and upgrade existing circuits within 5 years

Require all new control circuits to be either extra-low voltage

or RCD protected (not practicable to upgrade

existing circuits)


Safety

Welding VRDs

A VRD will not switch on the electricity supply before a genuine attempt is made to strike an arc, and will automatically cut off the power after welding ceases

Welding power will not be established if any person has inadvertently become part of the welding circuit and could receive a shock

(welding shocks constitute 37% of work practice failuresand 12% of all reported shocks)


Safety

Welding VRDs (voltage reducing devices)

Proposal:

Require all welding power sources exceeding certain minimum open-circuit voltages be provided with VRD technology within 2 years


Safety

Summary of electric shock incidents

Electric shocks are 3rd highest reportable incident

There is an electrocution every 2-3 years (the last was in May 2002)

Shocks to operators 41%, mechanics 27%, electricians 15%


Safety

Summary of electric shock causes

62% of shocks are due to equipment defects and 34% due to inadequate work practices

Major equipment defects: ingress of water 41% exposed “live” parts due to damage 19%

Major work practice defects: welding contacts 37% failure to isolate 25% “live” electrical work 21%


Safety

Summary of future regulation

Proposed “live” work regulations could eliminate 7% of all shocks

Proposed VRD regulations could eliminate 12% of all shocks

Proposed RCD regulations could safeguard 50% of the remaining shocks that occur

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