Consulting Engineers & Project Managers · Shaft Sinkers (Pty) Ltd. Title: Presentation to AMRE- No 16 Shaft rope accident Author: Diana Created Date: 3/22/2007 3:34:54 PM

Consulting Engineers & Project Managers

PRESENTATION TO THE A.M.R.E.

DESCRIPTION OF AN ACCIDENT TO THE No 16 SHAFT KIBBLE WINDER

WINDING ROPE

Shaft Safety Seminar – 8 March 2007

Mathew Watt


No 16 Shaft Project

Where?

Forecast completion date?

Production rate?

EPCM?

Shaft Sinking contractor?

Safety?

Consulting Engineers & Project ManagersDescription of the winding equipment

Slinging the drill jumbo to shaft bottom Sinking stage

Four drum stage winder Construction of headgear chutes


5,5 m kibble winder

16 ton payload kibbles

4 drum stage winder

120 ton stage (suspended from eight falls)

4,8 m sinking service winder

Kibble ropes: 48 mm 18 strand “Fishback” non spin

Extract of rock process flow diagram


Extract from the general arrangement drawing of the headgear kibble tipping system


Description of the accidentOn the 11 December 2006 the following happened:

The underlay kibble was in the process of being tipped

The lazy chain hook detached from the oblong link

The kibble swung uncontrolled into the swing chute of the overlay compartment

The force of impact was sufficient to open the swing chute into the compartment and trap the winding rope between the stationary and swing chute


Photograph showing the relative position of the swing chute, winding rope and stationary chute (from above)


Photograph showing the extent of deformation of the winding rope


Photograph showing the winding rope (from below)


Findings of the investigating teamLashing operations had not been carried out in the proceeding 7 hours

The pneumatic system is equipped with a supply side shut off valve. At the time of the accident the system was un pressurised

The WED witnessed the detachment of the lazy chain from the oblong (via Closed Circuit Camera and drivers display)

The winding rope was flattened to about 25 mm thick

The extent of damage could not be ascertained


Extract from the general arrangement drawing of the headgear kibble tipping system


Returning the winding system to normal operationThe suspended portion of the overlay rope was secured to the bank steel work

The overlay swing chute was secured by means of a chain block

The overlay swing chute was returned to the closed position using the pneumatic system

The damaged area of the rope was lowered to the bank for inspection



Observations made following the visual inspection:

• One broken wire in strand 1• One broken wire in strand 2• Damaged wires in strands 3 and 4• Two broken wire in strand 5• Damaged wires in strands 6 to 12• The displacement of the broken wires was measured as 1 m• Severely disturbed strand pattern

Returning the winding system to normal operation






Electro magnetic testing was conducted 70 m above and 20 m below the damaged area

The instrument showed a slight loss in steel area

Loose ends of the broken wires were removed

The displaced strand was returned to its normal position



EMT – 18 December 2006


Photograph showing the rope during repairs


Photograph showing the rope after repairs


Photograph showing the rope after repairs


EMT – 12 January 2007


The impact of the broken wires was assessed in accordance with the code of practice “ Condition assessment of steel wire ropes on mine winders” – SANS 0293

The operation of the pneumatic system for the swing chutes was proven

The winder was returned to operation (8 hours delay)



Application of SANS 0293The presence of broken wires was determined to have been of no significance

The variation in lay length exceeded that as recommended in 5.10.3 paragraph b (12 % deviation)




Long term prognosisOwing to the position of the broken wires and the proximity of another wire crossing over other wires which could not be rectified in the repair, which had the potential to be cause fordiscard, it was considered best to substitute this rope with the spare

The rope change was planned and completed on 27 January 2007

The damaged rope is now held us the “statutory spare”


Lessons learnedPneumatic system:System needs to be continually pressurised to ensure the chutes remain in the “home” position

Swing chute design:Eliminate the contact point between the stationary and swing chute


Remedial actionsInstallation of a cylinder to positively lock the swing chute inthe home position

Continuous monitoring of pneumatic system pressure

Master isolating valve changed from normally closed to normally open

Design changed initiated to eliminate the nip point




ConclusionWith a considered approach and calm heads – significant shaft sinking time was saved as well as the cost associated with discarding the rope

Pneumatic systems need to be assessed to understand what happens in the event of a lack of system pressure


AcknowledgementsImpala Platinum - Rustenburg Operations

Shaft Sinkers (Pty) Ltd

Documents

Consulting Engineers & Project Managers · Shaft Sinkers (Pty) Ltd. Title: Presentation to AMRE- No 16 Shaft rope accident Author: Diana Created Date: 3/22/2007 3:34:54 PM