A $200 million upgrade currently under way at Vale’s Clarabelle Mill in Sudbury will increase nickel recoveries by four per cent and allow for upstream copper separation.
The so-called CORe project, short for Challenging Ore Recovery, is a scaled down version of a project Vale was planning six or seven years ago, but abandoned in the aftermath of the market downturn in 2008.The current scaled down version got underway late last year with the construction of a new dry and was fast tracked to avoid overlapping with Vale’s $2.2 billion Atmospheric Emission Reduction (AER) project at its Copper Cliff smelter.
“We recognized that we had to accelerate CORe to avoid any overlap with AER because Sudbury is a fairly small community and we didn’t want to overload the trade labour force,” said Dave Stefanuto, senior project manager. “There’s also a little bit of a pinch getting professional engineers to do the design work as well, so we decided to move CORe forward by about a year to get a jump on the project.”
New dry facilities for the mill were a priority because “the old one was fairly dated…but, more importantly, we wanted to use the space where the old dry was located as a main electrical switch room to feed the new flotation plant we’re building,” said Stefanuto.
Flotation cells
A new 38,000 square foot flotation plant will be equipped with twenty 100-metre cubed Outotec flotation cells and three flotation columns. Work began on the new flotation plant in May and is scheduled for completion in July 2012.
Upgrades, including new flotation cells and the installation of a state-of-the-art IsaMill, are also planned.
The IsaMill, which is Xstrata technology, “allows for a finer grind than you get out of traditional ball or rod mills,” explained Stefanuto. “In a traditional mill, the shell rotates and the grinding media that pulverize the ore – balls or rods – are inside. With an IsaMill, the shell is stationary and there’s a shaft in the middle with grinding plates and small half-inch ceramic balls.”
The upgrades will allow Vale to produce a copper concentrate from the mill. Currently, copper is captured at the smelter.
“The upgrade will allow us to get the copper out earlier, so our smelter can focus on our higher grade nickel product, improving efficiency downstream,” said Stefanuto.
The 100-metre cubed cells planned for the new flotation plant are similar to the existing cells, but much larger and more efficient. The largest cells currently in use at Clarabelle are 38 metres cubed.
The upgrades will allow Vale to extract more value out of its ore and increase its resource base.
Work will begin on upgrading the existing plant once the new flotation plant is up and running in July 2012. The entire project is slated for completion by July 2013.
At the peak of construction, the project will create employment for between 150 and 200 skilled workers.
Installation work by local contractors will account for approximately half of the $200 million capital cost, said Stefanuto.
The work will consume 53,971 feet of pipe, 4,375 cubic yards of concrete, 1,780 tons of structural steel and 358,366 feet of instrumentation and electrical cables.
The engineering, procurement and construction management contract for CORe was awarded to Hatch.
