Sudbury Mining Solutions Journal is a magazine that showcases the mining expertise of North Bay, Timmins and Sudbury. This article is from the December, 2013 issue.
The mineralization at Vale’s Totten Mine is so rich, ribbons of copper, nickel and precious metal can be viewed at surface just by walking through the parking lot.
“It’s pretty interesting for anybody who likes geology,” said Lance Howland, Totten’s chief mine geologist. “They can go out for their lunch break to look at exactly what’s here, and that’s pretty much what you’d see underground.”
Totten Mine is situated along the Worthington Offset, one of the fractures resulting from the creation of the Sudbury Basin 1.8 billion years ago. Offset deposits like Worthington were formed when pressure caused by molten material cooling around the basin pushed its way into a fracture.
“(The molten material) carried with it the copper, nickel and precious metals, and formed multiple deposits along that string. One of them was Totten Mine,” Howland said. “It’s a pretty unique story and we’ve got some very interesting deposits that a lot of people around the world have come here to see given how unique it is.”
Totten Mine shares many of its characteristics with the Copper Cliff mines, including a comparable type of ore, and was modelled on the older mines, using many similar assumptions during the pre- easibility and feasibility stages of planning, Howland said.
“That’s why we’re modelled after the Copper Cliff offset,” Howland said. “We’ve got very similar rock types, very similar ore types, so a lot of the decisions that were made for this mine, from a geology perspective, were based on what we understood for the Copper Cliff North and South Mines.”
Rather than a solid mass of sulphides, the ore is comprised of a blend of lower grade metals with high- grade bands throughout the deposit, he said. He compares the metals to a stream flowing around a series of large boulders. After blasting a fresh area, the exposed deposit shows patches of no-value material surrounded by very high-value nickel and copper.
Though there has been exploration at Totten in the previous two years, none has taken place in 2013 while the focus has been on preparing for first production.
H o w e v e r , exploration is scheduled for future years. Howland said drill results and geophysics from the deposit show potential for e x p a n s i o n both vertically and horizontally. Vale does have targets selected for 2014, and will be following up on exploration once its budget is set for next year.
“We’re excited to get into that,” Howland said. “Our focus has to be on making sure our ore is figured out and to begin mining. The next step is to start adding to that, building on that potential.”
Another year won’t be long to wait, considering the Worthington Offset deposits were first discovered in 1884. Various deposits along the offset have seen multiple phases of mining through the decades. What is now the Totten deposit was acquired by Inco in the 1930s.
New deposits were found over the years, but it was drilling done in the 1990s that provided information to help define the deposit as it’s known today. Work on the current mine began around 2006-2007. The prospect of helping to develop a new mine—Vale’s first in 40 years—is exciting for Howland, who came over from Stobie Mine to work at Totten. Because a new mine startup is so expensive, and many mines have lives of 100 years or more, it’s a rare opportunity.
Setting up a mine today is vastly different from the mine setup of even 10 years ago. Technology like LIDAR mapping and 3D visualization software allow miners to conceptualize the deposit before tunnelling even begins, and wireless information systems such as those being used at Totten relay real- time information to geologists.
But, regardless of how much information has been gleaned from the deposit, the orebody still holds its mysteries.
“It’s a giant puzzle,” Howland said. “You’re always trying to figure out the puzzle, and the frustrating part is that you’re never going to be completely right until it’s completely mined out. That’s when you know what you’ve done and whether it was 100 per cent correct or not. You’re always putting out your best estimate until it happens.”