https://www.cbc.ca/news/science/what-on-earth-ropeways-clean-power-1.6042580
Ski lifts that carry cargo? Ropeways replace polluting trucks while generating clean power
(Doppelmayr Transport Technology Gmbh/CBC News) Trucks that spew carbon dioxide and toxic pollutants are often crucial for transporting cargo. But in some cases, there's a cleaner alternative — ropeways similar to the lifts that skiers use to get to the top of a mountain.
Bonus: They can generate green energy.
That's something Toronto-based Torex Gold does at its El Limn-Guajes mine in Mexico. Every hour, its "ropecon" — a ropeway/conveyer belt hybrid — moves 1,000 tonnes of crushed ore to a processing facility 1.3 kilometres away. (Check out the video here.) Bernie Loyer, vice-president of projects for Torex, said the company studied options for transporting the ore 380 metres down the very steep mountain, and concluded a ropecon would be cheaper and safer than trucks.
The system, installed in 2016, generates a megawatt of electricity through regenerative braking (the way electric vehicles and flywheels do). That's comparable to the power generated by a wind turbine.
"It's not a lot of power, but it's rare that you get an opportunity to move a thousand tonnes an hour at no net energy cost," said Loyer.
The technology isn't new. Ropeways or aerial tramways have been used for centuries to transport materials and cargo, and were still in use in Canadian mines in the early 1900s. Since then, they've been largely supplanted by trucks, which could transport the huge quantities required by modern mega-mines.
But there's renewed interest. Doppelmayr/Garaventa Group, an Austrian ropeway company that makes gondola lifts and cable cars, designed a new material ropeway system in 2001 after a customer requested it, said Silviu Varzecu, sales engineer for the subsidiary Doppelmayr Canada. Since then, it's been installing about one system every year or two, mainly for mining companies, including Torex.
Varzecu said such systems can cross obstacles such as rivers and cause little disturbance to the environment. Some are as quiet as a dishwasher, he said.
While there aren't any material ropeways operating in Canada right now, a B.C. mine aims to be the first.
Thomas Gardiner, director of environmental, social and governance for Taranis Resources, got in touch with us following our article on gravity energy storage, and says valuable ores on mountaintops are kind of like a natural, pre-existing gravity battery.
Gardiner has been working with Varzecu to design a ropeway for a mine near Revelstoke that the company is starting up again at a deposit that contains silver, gold, zinc and copper. In the 12 years he's worked on the project, Gardiner has driven up and down the "bumpy, jagged, nasty mountain road" to the mine many times. "We started to consider, well, what's it going to take to upgrade this road?"
Millions of dollars, he estimates, along with impacts such as logging. And the end result would be lots of noisy, polluting trucks going up and down a steep, hazardous mountain road.
Instead, in about five years, for a slightly higher initial cost, he hopes to build an aerial tramway that could move 14 tonnes of ore per hour 3.8 kilometres — 812 metres of it downhill — while generating 300 kilowatts of clean power. The electricity could potentially be used to charge electric trucks to carry the ore to be processed.
Gardiner added that once the mine is depleted and cleaned up, the ropeway could transition to a new role. "It's already a pretty popular area for skiing. You know, you can just turn the thing into a chairlift."
— Emily Chung