VEGA provides accurate water levels at Mesa A

Previous level measurement in a water cart.

VEGA’s Advanced sensing technologies have abolished a longstanding issue faced by many mining operators: the inaccuracy of water level readings in water carts.

Mining operators have been dealing with the issue of inaccurate water level readings in water carts. 

Rio Tinto manager mining, Robe Valley operations, Phil Scott and others recognise this as a persistent problem in the sector.

It was reported in the water trucks at Rio Tinto’s Mesa A iron ore operation in Western Australia during a pre-start meeting last year.

Rio Tinto approached Current Engineering Solutions senior electrical engineer Paul Smith, who has worked with VEGA radars in fixed plant environments for more than 10 years, to assess the concern.

Smith, recounting a story from a conversation with Scott, says he remarked how it is amazing that mining has trucks that drive themselves, but still hasn’t overcome the issue with the level indicator.

According to Smith, the problem originates from the use of mechanical switches and moving parts, which are “always a disadvantage”.

“The system they were using comprised multiple cable float switches that were held together with a plastic wire,” Smith explains. “This technology is unreliable due to its moving parts.”

A Newly installed VEGA sensor has delivered accurate water level monitoring.

 

Smith worked with VEGA Australia area manager (Western Australia) Andrew van de Sande to make sure Rio Tinto received a suitable outcome. 

First, they fully tested the VEGAPULS C11 series sensor and VEGAMET 841 controller in both a bathtub and swimming pool before they proceeded with a trial at the Mesa A operation. 

The installation of the VEGAPULS C11 and VEGAMET 841 sensors on Mesa A’s water trucks would be the first application of its kind for the products.

VEGAPULS C11 was released last year and is usually used for non-contact level measurement in water treatment, pumping stations and rain overflow basins.

“The new C series radar stood out as a good choice as it was well within the required dynamic range, extending up to eight metres,” Smith says.

“And being both contactless without moving parts, this was seen as the perfect choice to replace the existing system that comprised multiple mechanical type float switches.”

The VEGAMET 841 controller is an upgraded series of the VEGAMET model, an already proven sensor at Rio Tinto’s mine operations. 

It allows a simple conversion of pump controls and flow measurements on open channels, and weirs and totalisers.

Smith says what makes VEGAMET 841 a standout technology is the controller has a dedicated housing that withstands harsh environments, instead of being integrated to a switchbox or programmable logic controller (PLC).

“We put them through some rigorous testing in the bathtub and swimming pool for the conditions we were expecting them to be put under at the mine site,” van de Sande adds.

“We submerged them under water and we made large waves in the pool, but their performance surpassed all expectations. They worked beautifully without any teething issues.”

The private trial confirmed their confidence in the products’ new application, leading them to proceed with a trial at the Mesa A operation in December.

Smith says the Mesa A site team supported the trial by accommodating water cart access and an operator to work with for multiple cycles while on site. 

“They were also very proactive in implementing other elements that were required to be completed for a successful deployment, including the management of change for the trial and single point lesson detailing the new system,” he says. 

Rio Tinto testified of the accuracy of the system during the trial, having experienced zero reliability issues. 

“The sensor was very accurate, and to date, we have had no issues at all with reliability or accuracy. The operators now have an almost exact percentage or level height measurement that they can use to work out how far they can travel before running out,” Rio Tinto’s Scott says.

“This may not sound like a big deal, but in a very hot and dusty condition, water truck operators are often under immense pressure to keep up with the requirements of mitigating dust levels.”

Smith says it is frustrating to drive down a haul road for 40 minutes thinking there is enough water in the cart, only to run out and then have to drive back to refill the truck.

He explains that it creates more complications for the mine site. The higher movement of trucks means that they are creating more dust, while increasing vehicle interaction on an already busy haul road.

The unreliability of water indicators also translates to wastage when an overfill at the water stand happens, causing wash outs that put others at a safety hazard. 

“The system is now being sold as a complete pre-programmed kit with all the necessary installation materials, including the radar, display, mounting adapters, terminal box, terminals, glands and reducers for installation, as the water carts go into the workshop for a scheduled service,” Smith says. 

He anticipates that the company’s solution at the Mesa A mine will be a catalyst for mining companies to demand this standard of technology from OEMs.

“Knowing there’s a solution out there means that the problem will no longer be accepted,” Smith concludes.  

This story also appears in the May issue of Australian Mining.

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