ATC Williams

On top of tailings

Australian engineering consultancy ATC Williams has gained a reputation worldwide for its mine tailings expertise and continues to grow its knowledge and global reach. 

Over a history spanning more than 30 years, ATC Williams has gone from operating a small office in Melbourne to completing major engineering projects across the globe.

Today it provides a range of specialist engineering services to the mining, infrastructure and construction industries, but from the start its key specialisation has been in managing mine tailings.

The company has invested heavily in research over the years, driving several PhD scholarships on tailings and continually upgrading its specialist testing laboratory accredited by the National Association of Testing Authorities (NATA) in 1992. This facility has enabled ATC Williams to learn a great amount about the nature, behaviour and properties of mine tailings, all of which has had a significant and positive impact on the services it provides to clients.

Specialist knowledge

Innovation forms “a big part” of what makes ATC Williams’ service offerings better than those of its competitors, says ATC Williams Chief Executive Trevor Osborne. “That, as well as ensuring we really understand what we’re dealing with – the nature of the tailings, and how they’re going to behave in each case,” he adds.

“Understanding these things enables us to make the best use of the tailings’ properties, in order to minimise the cost and environmental impact of their storage and management.”

Having always been at the forefront of the tailings management industry, ATC Williams was the first Australian consultancy to use the Central Thickened Discharge (CTD) system; a method in which it is now seen as a world leader. Osborne considers that ATC Williams has probably used CTD systems in more applications than any other company.

“Where the topography and environment is favourable, CTD has made a big difference to tailings management, in a lot of ways,” he remarks.

“The key is to thicken the tailings to a point at which coarse and fine particles don’t segregate when deposited. By depositing from a single elevated point, you can effectively form a cone of tailings that are contained by relatively small embankments, which can dramatically lower the capital and operating costs over the life of mine.”

In applications where CTD is not the preferred option, ATC Williams will always have another solution. “In some cases conventional paddock storage will be cheaper and more effective, and in others we need to go beyond that to possibly filtered and dry stack solutions,” Osborne explains.

Moving into Chile

Osborne joined ATC Williams in the early 1990s in order to set up the company’s first office in Western Australia. He has been the company’s CEO and a Senior Principal Engineer for around five years now, during which time the company has expanded into Queensland through a merger with tailings / waste management specialist Alan Watson Associates.

The company is now launching its first office outside Australia, in Chile.

ATC Williams has been working in Chile since 2006, engaged in studying tailings disposal options for state-owned copper mining company Codelco. ATC Williams has completed studies at the mines and storages of El Teniente (storage at Caren and other alternatives), Andina (storage at Ovejeria), Salvador, San Antonio, Chuquicamata (storage at Talabre), Ministro Hales and Radomir Tomic. These copper mines typically have 20 to 40 years mine life and potential throughputs of up to 400,000 tonnes per day, meaning a large amount of storage is required to accommodate the tailings produced. ATC Williams has helped Codelco reduce the expense and environmental impact of the storage, after carrying out studies that included thickened tailings and filtration.

Codelco’s decision to use ATC Williams’ services again and again attest to the quality of their service. Nevertheless, the remoteness of these Chilean operations from ATC Williams’ Australian offices means they perhaps weren’t as efficient as they could have been had ATC Williams had a full-time presence in the country. Osborne anticipates that opening a Chilean office will not only streamline and otherwise optimise ATC Williams’ work in the country, but also make it easier to get further contracts there, which the company will be actively pursuing. ATC Williams has now established a regional company – ATC Williams Chile – and hired Carlos Pavissich, a capable engineering director to run it.

“Carlos has been working with us in the Melbourne office for the last 12 months, and is now in Chile finalising the last administrative arrangements before opening for business,” says Osborne.

“He was previously working for Codelco on a project in the tailings management area, and prior to that he was a project coordinator with a Chilean consulting office; so he comes with a good background for the role of heading up our operation in Chile.”

Tackling environmental challenges

The Chilean subsidiary’s initial work will be continuing its studies for Codelco in the Chuquicamata region. Previous work in the region involved a major tailings flume testing trial, through which ATC Williams gained a greater understanding of the way in which the tailings would discharge, at what angle they may beach; and what strength may be achieved on discharge. That trial led to a commitment to proceed with a field trial, which ATC Williams expects to complete sometime this year along with more detailed feasibility work.

Like a number of ATC Williams’ other Chilean projects, the Chuquicamata mine is located in the Atacama Desert. This makes the management of mine tailings on this project exceptionally challenging.

“The Atacama desert is the hottest, driest place in the world, meaning that water is extremely scarce,” Osborne explains.

“Many mines located there manage to operate solely by pumping water from the coast, typically over a distance of 100km and an elevation of 3,000m, and potentially desalinating it as well. This all adds up to very significant capital and operating cost.”

Such extreme conditions make the conservation of water crucial to the economics and resultant success of a mining operation. This is where ATC Williams’ expertise in minimising the environmental impact of tailings management – typically a large drain on available water resources – becomes incredibly useful.

“There are significant financial and environmental benefits to be gained through maximising water recovery from the tailings distribution process, by thickening or filtering, and at the same time using the resulting tailings’ properties to optimise storage design,” Osborne comments. “The same applies in many other cases in arid areas, such as in work we’ve done on projects in the Middle East.”

Minimising a mining project’s environmental impact also includes reducing energy use and protecting against risks such as groundwater contamination; both of which form significant aspects of any tailings project assessment.

Extending its reach

Besides Chile, most of ATC Williams’ work has been in Australia but to a lesser extent it has worked in almost every continent of the world. The company currently has work underway in Africa, Europe, the Middle East and Asia that it will be continuing this year.

“We have ongoing work at a gold mine in Sudan, where we’ve been for a couple of months now; we’ve been working in Sweden and Spain, and there could be some more work to come from there; and we’re working on a significant project in Peru,” says Osborne.

“We’ll also continue with work in Iran as we have since 2000; and we’ve been working for a number of years in Kazakhstan, and there’s a possibility there’ll be more work to follow there.” 

He adds that the company currently has good prospects in Poland and Mongolia.

But a key goal for 2014 is to continue expanding its knowledge and expertise, particularly in its new Rheology and Slurry Engineering Group. This business group was set up in November 2012, building on many years of slurry pipeline work undertaken for the tailings projects, and is being led by distinguished Professor Paul Slatter.

“Paul was previously Professor of Rheology and Slurry Engineering at the Royal Melbourne Institute of Technology; he’s a world leader in that area and on numerous international committees working in that field, so he’s a real asset to the company,” Osborne explains.

“Over the past year, his group has been continuing in the design of tailings transport: from the thickeners that might be required, to the pumps and pipelines that transport the slurry.  We can now provide this service to a broader range of industries – in fact to any industry which involves pipeline transport of slurries. In this regard, there is scope to be of assistance to companies involved in waste water treatment, dredging, power generation and chemical industries.”

To support slurry transport design, the laboratory in Melbourne has now added a pipe loop (to better assess rheological properties) and will soon add a ‘wear wheel’ (to measure the long-term wear effects). These devices help determine the most suitable pipe size and material for each application. This year is likely to bring more developments as ATC Williams continues to invest in research, so that it can provide the best service possible.

“Paul’s input has enabled us to better service our clients, which, at the end of the day, is our only long-term goal,” says Osborne; “to continue doing what we do better than anyone else.”

www.atcwilliams.com.au

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