Stacker Reclaimer and Coal Terminal Demolition: How Port Machines Come Down

A stacker reclaimer is a machine, not a building, and that is the first thing to get straight. It has a slew bearing, a luffing system, counterweights, a bucket wheel or a boom conveyor, hydraulics, a rail travel system and a few hundred tonnes of structural steel balanced around a pivot. Take it apart in the wrong order and it moves on its own. The same goes for shiploaders, ship unloaders, stackers, transfer towers and the conveyor galleries that tie a coal or ore terminal together.

This is how we approach port machine and coal terminal demolition, what will hurt you, and where the money is won or lost.

What you are actually dealing with

• Slewing machines with live counterweights. The boom, the bucket wheel and the counterweight sit on a slew bearing in balance. Remove one without accounting for the others and the machine tips or spins.
• Rail mounted travel systems with their own bogies, drives, rail clamps and anchor points, on a wharf or stockyard rail that still has to be protected or removed.
• Conveyor galleries and transfer towers: long span steel with belts, idlers, drives and chutes, often carrying asbestos in brake linings, gaskets and old lagging, and lead paint on older structures.
• Coal and ore dust everywhere. Coal dust in enclosed galleries is an explosion risk when hot work starts, and the dust in a terminal that has run for decades can carry heavy metals that make the waste harder to classify.
• Marine conditions. Salt has worked on the steel for 30 or 40 years. Sections that look sound on the drawings are not.
• A live terminal next door. In almost every case the port keeps operating, the berth is wanted back on a date, and the shipping schedule does not move for you.

Step one: decide between dismantling and demolition

Some port machines are sold and relocated, some are dismantled in large sections and craned out, and some are cut down in place with high reach shears once the hazardous materials are gone. The choice depends on the condition of the steel, the crane access on the wharf, the berth window and the salvage value. A machine that is being sold needs its hazardous material survey before it ships. A machine being scrapped needs an engineered sequence that keeps it stable at every stage. Decide this first, because the two jobs share almost nothing after the isolation stage.

Step two: investigate and isolate

Hazardous material survey covering gaskets, brake linings, flange packing, cable insulation, switchrooms and any building on the structure. Lead paint sampling on the steel. Dust sampling in galleries and chutes. Then electrical isolation at the terminal's supply, hydraulic depressurisation and draining, lubricant and fuel removal, and the lock out of the travel system so the machine cannot move in the wind. Wind is a real load on a boom; the parking brakes and storm anchors stay on until the engineered sequence says otherwise.

Step three: get the balance right before the first cut

A structural engineer models the machine at each stage of removal. The counterweight is usually reduced first, in steps, with the boom supported or lowered. Only then does the boom or bucket wheel come off. Crane lifts on a wharf are limited by the deck's rated load, so the lift plan and the deck engineering go together. Every cut is a planned cut with the machine's centre of gravity known before and after.

Step four: hazardous materials and dust

Asbestos gaskets, brake linings and lagging are removed under the asbestos licence before hot work starts anywhere near them. Lead paint is managed through controlled cutting and capture rather than open flame cutting on coated steel. Galleries are cleaned of coal dust before cutting; it is slower than it sounds and skipping it is how terminals catch fire. Where the terminal is still operating, dust from our work is a problem for their plant as much as for our people.

Step five: take it down in the right order

Once stable and clean, the structure comes down from the top in engineered sections. On a wharf the sections are craned to the deck or to a barge and processed on a laydown area. In a stockyard a high reach excavator with a shear handles most of it from the ground. Transfer towers and gallery spans are dropped in controlled lifts or felled onto a prepared pad. The rail is lifted last, after the machine is gone, and the wharf deck or rail beam handed back in the condition the asset owner specified.

Step six: the steel and the ground

A stacker reclaimer is several hundred tonnes of recoverable steel, plus copper in the cabling and drives. Weighed, graded and credited against the price, it changes the economics of the job. Under a stockyard the ground is coal affected and often needs classification before anything leaves the site. Under a wharf, anything that falls in the water is a problem you do not want, so exclusion screens and catch platforms go in before cutting starts.

What not to do

• Do not cut the boom before the counterweight has been dealt with. The machine will rotate or tip.
• Do not hot cut coated steel in a dusty gallery without cleaning and ventilation. Coal dust burns.
• Do not lift from a wharf deck without a rated load check. Older decks will not carry a modern crawler crane and its load.
• Do not let the scrap merchant run the job. The steel is the easy part; the stability, the asbestos and the live terminal are the job.
• Do not let anything fall in the harbour. Recovery costs more than prevention every time.

Approvals and notifications

Port authority approvals and permits to work, marine notices where cranes or barges affect navigation, licensed demolition notification to the state regulator for structures over the height threshold, licensed asbestos removal notification, and waste classification for coal affected material. Where the terminal is on reclaimed or contaminated land, the EPA may be involved in what leaves the site.

Who should be doing this

A contractor with its own high reach and remote controlled plant, its own Class A asbestos crews, a structural engineer it has worked with on machines like this, and people who have worked inside an operating port before. Perfect Contracting carries out industrial and port infrastructure demolition across Australia from its Sydney and Brisbane bases and travels for the right project. If you have a stacker reclaimer, shiploader or conveyor system coming out, the earliest conversation is the cheapest one. Read more about our industrial demolition and plant decommissioning work, or send us the details.