nathan welsh: northparkes mines - winder east skip derailment
TRANSCRIPT
-
Northparkes Mines Winder East Skip Derailment Nathan Welsh, Senior Maintenance Engineer
-
Northparkes Mines
-
Winder Friction winder
Non Man Riding (Excluding
Maintenance & Emergency
Egress)
500 Metre Lift
MDG33 & MDG2005 Compliant
SIL Level 2 Compliant
Single materials handling
source of ore from the
Underground Mine
-
Winder Head Ropes Haulage Rope
Tail Ropes Balances Head
Rope Load
Guide Ropes Locates Skip in
Horizontal Plane
Guide Rope Weights Provides
Guide Rope Tension
Arrestor Frame Physical Barrier
E-Cam Communication from
Skip Devices to PLC, Utilises
Head & Tail Ropes to Transmit
-
Fixed Guide Operation
Fixed guides are
installed at the skip
loading and
unloading points
Prevents horizontal
movement of the skip
when loading and
unloading
-
Fixed Guide Operation
-
Incident Details
Time and Date of Incident: 1:38am
10th of March 2015
Incident Location: Main Winder
Loading Station Docking Point
Duration: 9140 minutes (6.3 Days)
-
Incident Aftermath
Lower Shoes on East Skip Did
Not Engage with Fixed Guides
Four Structural Beams Damaged
East Skip Stuck on Fixed Guides
at Loading Station Docking
Point
-
Timeline 01:35:49 Winder Tripped E-Cam Fault & Tub Latch Fault
@ Fresh Air Base
01:45:20 Winder Started in Manual
Lower Shoes on East Skip Do Not Engage with Fixed Guides
01:45:36 Winder Tripped E-Cam Fault & Tub Latch Fault
-
Timeline 01:47:10 Winder Started in Manual
01:47:15 Winder Tripped E-Cam Fault & Tub Latch Fault
Post 01:47:15 Maintenance Technician Calls SCADA to Shutdown
Winder due to Loud Noise Winder is Isolated East Skip
Derailment Identified
-
Photos
-
Investigation Investigation Item Outcome
Misalignment of Conveyance Due to ballast weight, liners, ore hang up, or skip moving within the bridle Disproved
Misalignment of Fixed Guides Due to impact damage (prior to incident), fatigue, or corrosion Disproved
Uncontrolled Entry into Fixed Guides Due to fault in the winder control code or elongation of the head ropes Disproved
Induced Conveyance Oscillation Due to loose or worn guide rope shoes/slippers, air flow, or obstruction in shaft Disproved
Guide Rope Oscillation Due to failure of stauff clamps or insufficient guide rope tension Disproved
-
Investigation Investigation Item Outcome
Misalignment of Conveyance Due to west shoe failing when struck by fixed guide Contributing Factor
Induced Conveyance Oscillation Due to acceleration/deceleration when restarting mid shaft in Contributing Factor manual, insufficient guide rope lubrication, or the skip stopping in a zone of high turbulence (fresh air base)
Investigation reviewed by OEM and 3rd party
Contributing factors identified but root cause could not be verified
3rd party modelling could not replicate incident using known
parameters
-
Controls Contributing Factor Countermeasure/Control
Misalignment of Conveyance West Shoe Failed When Struck by Fixed Guide
Induced Conveyance Modified control system so that skip will slow Oscillation: to 1 m/s at 25 metres above the fixed guides - Accelerating/Decelerating when in manual
when restarting mid shaft Greased guide ropes and confirmed 4 - Insufficient Guide Rope
weekly guide rope greasing is active inLubrication system - Shaft Air Flow
In addition Northparkes Mines is investigating the option of increasing
guide rope weights to reduce conveyance oscillation
Updated 4 weekly winder inspection with criteria and actions for visual inspection of the guide shoes
-
Summary Winder tripped 3 times on e-cam & tub latch fault
Lower Shoes on East Skip Do Not Engage with Fixed Guides
between 1st and 2nd trip
Multiple contributing factors were identified in the
investigation however a root cause cannot be validated
Actions were implemented to control identified contributing
factors before resuming production
Additional countermeasure is under investigation
Slide Number 1Northparkes MinesWinderWinderFixed Guide OperationFixed Guide OperationIncident DetailsIncident AftermathTimelineTimelinePhotosInvestigationInvestigationControlsSummary