In-situ Testing of VCDs: Aquacrete and PB Launch New Non-Destructive Testing Technique

Aquacrete, the Australian owned and operated ventilation control specialist, has developed in-situ testing technology that will allow underground mine operators to non-destructively verify the thickness and therefore overpressure rating compliance of ventilation control devices (VCDs). Launched at the Australian Mine Ventilation Conference at the University of New South Wales on 6 September, the Aquacrete Thickness Gauge (ATG) can accurately analyse existing and new installations without the risk of damaging the material structure of the VCD.

While sample coring and analysis of installed seals has provided significant assurance to mines, it is difficult, time-consuming and costly to carry out physical sampling and testing of every installed VCD. As a result, over the past three years, Aquacrete and international engineering consulting firm, Parsons Brinckerhoff (PB), have co-operatively developed a method for in-situ, non-destructive testing that addresses these issues. Although a new approach to testing underground VCDs, the method employs recognised testing equipment in a new application.

“The Aquacrete Thickness Gauge uses sound waves to test a material for integrity and strength properties. It works by striking a surface with a hammer built in to the testing device and then measuring the elapsed time for the sound waves to reflect off the far surface,” PB Technical Executive for Energy, Mining and Industry, Michael Salu, explains.

“If there are any defects within the material, such as voids, the sound waves will not transmit through and the instrument will record the sound waves bouncing off an apparently thinner section.”

Mine operations can take multiple readings across the surface of the installed VCD, providing further reassurance that the seal has been installed to the required standards.

Aquacrete Business Development Manager, Greg Kay, says there has been a lot of support for the new technology. Having conducted a range of tests in the laboratory, above ground, at trial underground sites and in active mine operations, Aquacrete and PB were invited to present a paper on the new technology at the University of New South Wales conference.

As underground mines increasingly face the challenge of maximising production without losing focus on safety excellence, Kay says the ability to predict the effectiveness and identify defects in mine seals and stoppings plays an increasingly important role in mine ventilation management.

Reinforcing their shared commitment to establishing more consistent engineering standards for VCD construction, Salu and his team at PB have worked with Aquacrete over the years to develop a range of engineering, design and monitoring tools for the underground mining sector.

Salu believes the new testing technology is a much-needed development for the industry:

“Having a reliable and accurate means of non-destructively testing seals in-situ provides substantial operational and safety benefits to the underground coal mining industry.” he says.

The new equipment will form an integral part of Aquacrete’s mine support program, where the company provides site audits and VCD inspections to not only assess the installation requirements for a site but to monitor the integrity of installed seals and stoppings over time.

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