Suspended automation

The need to create a safer mining environment is seeing the person taken out of the actual operations more and more.



Automated and robotic systems are now offering safer ways to carry out tasks that were previously done by putting a person in unnecessarily dangerous circumstances.

Australian contract mining and services company Jetcrete has been leading the way in making the securing of vertical mine vent shafts safer through automating mining operations.

An integral part of mining operations, effective vertical shafts are needed to ensure maximum air flow as well as being used as escape ways and ore passes.

Previously, the method of lining and securing these shafts involved sending a person down in a cage suspended by cranes to shotcrete the shaft.

To counter this, the company developed Tele Remote Shaftlining.

This new method incorporates a tele robot which eliminates the need for people to enter the shaft.The robotic system allows for control and monitoring of the spray application via CCTV from a remote control station positioned away from the shaft opening or collar, which offers the operator vision of the spraying through cameras attached to the module.
Jetcrete manager Shane Hollis told Australian Mining one of the major assets of the module is the safety and time aspects.

"The two major dangers in working in shafts is either someone falling down the shaft or when working with suspended lines, something may fail and fall down the shaft on someone below.

"By eliminating the man in the shaft it eliminates the risk of someone falling down it."
The shaftlining unit comes with cameras that have a full 360 degrees of focal view which lets the operator monitor and control the spray nozzle actions and application patterns of the fibrecrete.

The robot is lowered into the shaft via a winch which controls the ascent and descent speed as well as the depth of the module and is monitored by a digital device that appears on the same operator screen as the CCTV footage within the control cabin.

The cabin also houses a water meter and adjustment valve allowing the operator to view, log and manipulate water usage to adjust water flow through the nozzle to achieve the correct slump.

The water hose is grouped together with a data and an electrical cable into a single cable called the Umbilical Cable which is linked to the control cabin via a motorised cable drum.

The contract mining and services company Jetcrete has also approached the fibrecrete application differently to obtain more effective spray coverage.
Unlike common fibrecrete or shotcrete applications, it is not mixed with any water until it has been pumped through the delivery lines and reaches the spray module.

This method, known as dry mix application, allows the operator to achieve the desired slump.

This method is used due to the difficulty in pumping ‘wet’ concrete downhill through hoses at considerable depth.

The ability to do this quickly and effectively is a major factor, Hollis told Australian Mining.

When lowering people down there needs to be a number of risks assessments and lift rating assessments, whereas lowering the machine down requires very few

"Whereas it may take a week before people are lowered into the shaft, it normally takes a day from the trucks arriving to spraying beginning."

On top of this, the machine spraying is almost a nonstop process, where as with people hoses must be disconnected every time the cage is lowered, he said.

To date, the module has been successfully employed in spraying and securing shafts at depths in excess of 300 metres, with new modules being developed to achieve spraying depths of 500 metres and potentially deeper.

It has an operation range in shafts with circumferences of between 1.5 metres to 9 metres.

Jetcrete is also developing 3D laser mapping technology to achieve more accurate profiling and applied thickness measuring of the vertical shafts during spraying.

Jetcrete currently has three shaft lining modules in operation in Australia, with further capacity to operate within Indonesia and North America.

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