“Fuel cells right now are expensive, but the price is going down 15 per cent on a year to year basis, so we’re fast coming to the point where the capital and operating costs for diesel and hydrogen power plants will be the same.”
A consortium under the umbrella of the U.S.-based Fuelcell Propulsion Institute is currently surface testing a Caterpillar R1300 loader in Arizona and plans to continue with underground trials at Barrick Gold’s Turquoise Ridge Mine in Nevada and at Agnico Eagle’s La Ronde Mine in northwestern Quebec.
The loader is equipped with a hybrid power plant that provides supplementary power from rechargeable batteries for peak power demands. Battery power kicks in “when you are going up a ramp or loading up your bucket,” said Bétournay.
“Fuel cells will easily handle the peak load, but they cost a lot more than rechargeable batteries, so it’s just a smart thing to do.”
Also in the works is an infrastructure demonstration project at CANMET’s experimental mine in Val d’Or, Quebec. The proposed underground delivery
and refueling system will supply hydro-gen through a quarter-inch or half-inch pipe in the mine’s exhaust raise to refueling stations on various production levels.
The hydrogen will be stored on the loader in a metal hydride storage system.
“It fits very nicely between the large metallic ions,” explained Bétournay.
“There’s a weak chemical bond, so it doesn’t diffuse immediately. It needs to be heated just a little bit using waste heat from the fuel cells and batteries, so the hydrogen will flow.
“Then the hydrogen gets to the fuel cell, does its electrical thing and recombines with oxygen to give you water.”
Bétournay is confident that the system is safe.
“All of the hydrogen storage systems now are extremely well done and extensively tested so that even if there is a break, it’s to a certain extent self-healing. It’s not going to be an explosive situation.”
Piping hydrogen underground is preferred to avoid tying up a mine’s cage or ramp with continuous deliveries of gas cylinders.
A study by the Hatch Associates technology consulting group in Sudbury pointed out several options for the supply and delivery of hydrogen to a mine. It can be trucked from afar, produced and supplied regionally in a mining camp such as Sudbury, or manufactured at a minesite
Hydrogen can be produced through a so-called reforming process, which strips away hydrogen from an organic fuel such as diesel or natural gas, or by electrolysis, which separates it from water.
The reforming process is less environmentally friendly because it
emits carbon dioxide, but it’s only one-third of the carbon dioxide that is emitted using die-sel power plants, said Bétournay. Electrolysis is the more expensive option.
The mining industry’s interest in hydrogen fuel cells has been driven by health and safety issues relating to diesel particulate matter in the confined spaces of an underground mine.
In addition to health and safety benefits, hydrogen fuel cells will also reduce underground ventilation requirements.
“By using hydrogen fuel cells, you are saving a ton of money on ventilation – somewhere between 20 to 60 per cent of ventilation costs,” said Bétournay.
But there is still a lot of work to do. “We’re not at the point where we can tell industry, ‘You have everything in hand. Move forward.’”
Before mining companies move to a new technology, they will have to be satisfied that regulations governing the use of hydrogen underground “won’t handcuff them” and that they can source equipment and get the support they need, said Bétournay.
Several speakers from Sudbury, including CANMET’s Stephen Hardcastle, Doug Eastick from Hatch Associates, Al Akerman from Inco and Fred Delabbio of Rio Tinto will deliver technical papers on hydrogen fuel cell technology at the 1st International Symposium on Fuel Cells Applied to Mining April 29 in Montreal. Chaired by Bétournay, the symposium coincides with the Canadian Institute of Mining and Metallurgy’s annual conference and exhibition, which runs from April 29 to May 2.