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The scale of the problem

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One of the major problems in minerals processing is the constant maintenance and cost of production.

Which is why the industry has looked to automated solutions to fix problems such as scale build up to reduce not only the cost and time eaten during maintenance, but also the cost of production. 

A new, Australian first integrated scale control and management program implemented at Newmont's Boddington gold mine's processing plant is helping the miner address costs and increase production. 

The miner has worked with Nalco, which designed and installed the automated scale control system, which includes site specific anti-scalant (which was developed after a series of water quality tests), a regulated dosing point and a remote deposit monitoring (RDM) control centre, which is cross-linked to Boddington's processing circuit distributed control system (DCS). 

Described as a step change in scale control, the RDM technology measures scale formation rates in real time in a process side stream. 

This technology also provides 24 hour remote monitoring for both the Boddington metallurgical team and the system supplier to actively monitor the system and keep track of is current operational state, allowing for a quick response to any adverse scale events without any delay. 

This ability to react quickly cuts down the potential for production interruptions or possible plant shut downs in a worst case scenario. 

Nalco stated that the system can also be configured to measure temperature, pH, and the conductivity of the process water to build a wider picture of scale formation and the chemical drivers that cause it. 

Paul Petrucci, the senior metallurgist at Boddington, said the integrated system - the first of its kind in Australia - has meant a tangible reduction in the frequency of scale, and its impact. 

"[The RDM system] has been a good solution to the scale problem," Petrucci said. 

He explained that prior to the RDM commissioning Boddington was inadvertently dosing excess lime into the process water system during short, unplanned outages, causing a scale build-up. 

"As a result of the data from the RDM we can identify this previously misunderstood scaling event and alter the control scheme to prevent its occurrence. 

"The data the system is providing means we can be more aggressive with optimising our anti-scalant dose rates and critically, match the required dose to the quality of the feed water. 

"This is saving us money reducing anti-scalant purchases and improving the operation of the process circuit" while also cutting down the frequency of scheduled maintenance. 

The new pro-active treatment of scale problems has also aided the process water itself, improving the availability of the water within the plant. 

"The RDM system is giving us a total understanding of the scale process and, ultimately, improving process water quality," Petrucci stated. 

According the Nalco, the scale control program at the Boddington process plant is, in common with scale control in any mineral processing plant, a dynamic process. 

It went on to say that systems such as the one at Boddington are likely to become more common for Australian mines as "water quality and consumption rates will impact on the frequency and intensity of scale events and require an equally flexible management system". 

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