Headgear ErectionThe Impala 17 Shaft ExperienceMichael Yates AMRE Safety Seminar 18 September, RPM Club: Lifting Operations

Introduction

Introduction

Impala 17 Shaft Headgear Tower type headgear propped on two sides 81m to the top of the crane rail Centre tower foot print is 14m by 14m square The two braced raking back legs extend to about 42m from the shaft

centre line

Multi Phase Design

It must accommodate 3 conditions Sinking, development and construction – from 2009 to 2017 Equipping and commissioning – from 2017 to 2018 Permanent condition – for the productive 30+ year life of the mine

Design: Working Condition

Raking legs for two ground mounted Koepe winders placed at 90° angles to one another

The deepest Koepe wind to date at 1932m deep Skips running at 18m/s with hoisting capacity of 33 ton Man cage is a double deck cage with counterweight and

accommodates 150 men per deck Service cage is also a double deck cage to take 54 men per

deck and with planned slinging capability of 8 ton

Design: Emergency Condition

The headgear is designed for 1.5 times breaking force of 6 50mm ropes

This factor compliments the winder base design Incredible force of 2500kN per rope = 22,500kN. This force is directed from the 60m level through the back

legs into the ground This causes a substantial torque on the head frame

Fabrication

Large sections to handle in a workshop i.e. plate girder in the order of 2.5m deep

Heavy cruciform column sections Pin and bracket assembly for the raking legs Large trial assemblies of the floors in the workshop

Headgear Erection

Site establishment was in August of 2008 The erection duration was 7 months and ended in February

2009 The final paint coat was applied just prior to assembly and

erection on site Lower four floors were assembled with the columns on

erection bases adjacent to the headgear From the 38.5 m level up the erection was carried out

piecemeal Single beams with a mass of 25 tons were lifted to heights of

up to 70 m

Erection Overview

The stair access tower was to be erected in sequence with the floor levels

The headgear tower was erected well within the code requirements (32mm deviation at the top and 140mm is allowed in the code)

The back legs were erected in two preassembled sections, each weighing 80 tons

Interesting Facts

Interesting Facts

Impala 17#, Rustenburg 2009

81.0m

Interesting Facts

69281 Bolts supplied1850 Total tonnage1430 Tons painted420 Tons galvanized1099 m handrails1200 m² flooring406 Stair treads

100000 Manhours on site20000 m welding

8679 Individual pieces of steel2650 Drawings generated

150000 km's for transport and delivery

Preparation

Detailed risk assessment carried out in June 2008, aspects considered: Assembly and disassembly of the lattice cranes Crane erection Use and movement of the cranes Preassemble and erect the headgear tower Preassemble and erect the raking legs

Risk Assessment

Aspects considered: Failure of the equipment; ropes, brakes and components Incorrect operation of the crane; incompetency, lack of skill Injury to persons, damage to equipment; unsafe rigging methods Concurrent activities in the work area; falling objects, poor

communication Inclement weather; wind, rain, lightening, cold, heat Incorrect material handling; unskilled labour, lack of supervision, poor

planning Incorrect rigging; lack of knowledge, lack of training, non adherence to

standards Lifting point failure; poor design, poor installation, shock loading Working at heights; poor housekeeping, slippery surfaces, inclement

weather

Risk Assessment

Aspects considered Exposure to hazardous substances; inhalation of fumes, contact of

products Concurrent activities in the work area; falling objects, poor

communication Fire; hot work, electrical failure Non adherence to legal requirements; relevant acts Poor communication; lack of coordination, poor attitude, poor planning Unsafe ground conditions; compaction, rain, sub surface structures Unsafe scaffolding; standards, uncertified erectors, poor ground

conditions, equipment, poor design

Risk Assessment

Aspects considered Collapse of trestles; poor design, uneven loading, unstable ground Poor fitting of HD bolts; incorrect survey, negligence, dimensional

errors Limited access for haulage; close proximity of winder buildings Poor ergonomics; nature of the design Suspended platforms; ergonomics, overloading, mechanical failure

Risk Assessment

Alternative Crane Arrangements

Underground structures required support: Beneath the terrace adjacent to the main shaft are there the access-

ways and a service duct. These were assessed and it was decided to brace and prop these

structures. Areas were demarcated where the assembly cranes were not allowed

to access

Site Preparation

Propping Underground Structures

Lift Planning

Detailed lift planning was carried out considering: Positioning of the main cranes for each lift. Mass and height of each lift. Lifting equipment to be used. Spreader beams required.

Lift Planning

Headgear Layout

Raking Legs

Tower Structure

Crane Gantry

Establish 400Ton Lattice with 66m Main Boom, 120T Counterweight and 130T Superlift Counterweight

Lift 1st Floor (14.5m Lvl) from preassembly pad over Matla HeadgearMass of lift 130 Ton

Move crane back and lift 2nd Floor (20.5m Lvl) From 2nd preassembly pad onto headgear. Mass of Lift 55 Ton

Lift Stair modules into position up to 26.5m Lvl

Lift 3rd Floor (26.5m Lvl) from first preassembly pad on to headgear. Mass of Lift 55 Ton. Lift stair modules up to 32.5m LVL

Lift 4th Floor (32.5m Lvl) From 2nd

preassembly pad onto headgear. Mass of lift 55T

Lift stair modules up to 38.5m Lvl. Change boom configuration adding 30m Luffing fly and removing Superlift. Establish 225T with 106m boom in Skyhorse configuration.

Erect 5th Floor (38.5m Lvl) piecemeal with both cranes, max lift 35 Ton

Lift stair modules up to 44.5m Lvl

Erect 6th Floor (44.5m Lvl) piecemeal with both cranes, max lift 35 Ton

Erect 7th Floor (50m Lvl) piecemeal with both cranes, max lift 35 Ton

Lift stair modules up to 60m Lvl

Erect 8th Floor (60m Lvl) piecemeal with both cranes, max lift 35 Ton

Change boom configuration back to 66m boom and 130T Superliftcounterweight, move to South West of headgear to lift preassembled bottom portion of backleg. Mass of lift 80 T

Move crane in position and lift preassembled upper portion of backleg. Mass of lift 80T

Move crane in position and lift preassembled bottom portion of backleg. Mass of lift 80T

Move crane in position and lift preassembled upper portion of backleg. Mass of lift 80T

Move crane back to East of headgear, Change boom configuration to 78m Main boom and 30m luffing fly jib. Bring 225T Crane back in to position. Install stair modules up to 70m Lvl

Using both cranes, erect 70m Lvlpiecemeal max lift 35 Ton

Install stair modules to top and finish 70m Lvl

Lift north elevation of crane gantry into position

Lift south elevation of crane gantry into position

Lift east walkway of crane gantry into position

Lift west elevation of crane gantry into position, place EOT crane and disestablish cranes

Putting the Plan in Action

Establishing Site

14.5m Lift

14.5m Lift

20.5m Lift

20.5m Erected

26.5m Lift

32.5m Lift

32.5m Erected

38.5m Frames

38.5m Frames

38.5m Piecemeal

38.5m Piecemeal

DSE Workshop Inspection

44.5m Piecemeal

44.5m Frame

One Dark Stormy Night05 November 2008 at 23h30

Some Incidents to Recall

Houston Texas: 16 July 2008

Houston Texas: 16 July 2008

‘Big Blue’ Milwaukee - Wisconsin: 14 November 1999

‘Big Blue’ Milwaukee - Wisconsin: 14 November 1999

Bellevue WA: Tower Crane21 Nov 2006

Crane Collapse

Crane Collapse

Crane Collapse

Key points from the investigation: 225T American 9310 crane was rigged in ‘Sky Horse’ configuration

with 106m boom, boom angle 73°. High wind speeds recorded (50km/h). Effect of the wind was multiplied by the proximity of the sheeted winder

buildings. Fortunately there were no injuries and no damage to other structures.

The program was maintained by revising the erection sequence and mobilising an additional crane

Crane Collapse

50m Erected

Raking Leg Preassembly

60m Erected

60m Erected

Laydown Areas and Painting Area

Columns to the 70m Level

Raking Leg Preassembly

Raking Leg Preassembly

Kibble Shaves on the 60m Level

Stage Winder Rope-up

70m Erected

Crane Installation on 81m Level

Stair Tower Preassembly

Tower Compete

Man Winder Raking Leg Erection

Preparing to Lift Rock Winder Raking Leg

Rock Winder Raking Leg Erection

Rock Winder Raking Leg Erection

Rock Winder Raking Leg Erection

Erection Complete

Site Disestablishment

Final Survey

Following the Big Blue Incident: Implement specifically engineered lift plans designed by professional

engineers based on rated capacity, measured weight of the load, thorough study of the wind speed and its effect on the load, and consideration of ground conditions and dynamic forces on the crane's stability.

Cranes and work areas should be equipped with wind instrumentation at or near the elevation of hoisted loads.

Suspended personnel platforms should not be used in adverse weather conditions which may endanger workers.

Provide alternate observations methods for locations not easily visible from the ground.

Only use personnel necessary to safely complete the lift in hoisted platforms.

Lessons Learnt

Following the Impala 17 Shaft Incident: Consider the effect of prevailing wind conditions exaggerated by

surface features and buildings. Wind monitoring equipment to be installed and monitored even after

hours, alarm systems to be considered. Crane to be parked with the slew brake off. Boom to be lowered to 45° at end of daily site activities. Risk assessment reviewed.

Lessons Learnt

Headgear Erection: Erected successfully without any lost time injuries. Exceeded the required degree of accuracy.

Lessons Learnt

Owner/ Client: Impala Platinum

Main Contractor/ Engineer/ Project Manager: TWP (WorleyParsons)

Steelwork Contractor: Grinaker-LTA

Steelwork Fabricator: DSE Structural Engineers

Credits

Presentation Close