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It is more than just a big, old black steel pipe on the side of a back road.
Further down the same back road, there is no heritage recognition for a horizontal, box-like, concrete structure with a multitude of broken windows.
Within the building perched high up on a cliff, a protruding pipe extended purposely 85 metres down to the Montreal River below; closer examination reveals that a multitude of pipes with aging cracks and rusty remains most people would not pay attention to, but we should. And someone is.
It is one of the greatest technological achievements in the history of Northern Ontario and its creation made a difference on a scale that is difficult to comprehend. And the energy-efficient concept is now back.
Monuments are built to remind us in the future about something that people in the present consider too important to forget. And because of a heritage marvel, modern mining will benefit from an energy-efficient idea updated to the contemporary.
Close your eyes, tighter, and imagine an eruptive geyser. When you look at the accompanying photos and visit Cobalt you won’t see this geyser. At one time, particularly on weekends, families flocked to see what was called “Fountain Falls” or “Old Faithful,” a subterranean wonder.
Unlike the Yellowstone natural phenomenon, this column of water was much higher but was a by-product of a process. It was a tourism attraction. It was also the site of the world's only water-powered compressed air plant. And because of what was future mining will go towards the centre of the Earth.
In both time periods, it is an engineering marvel. Charles H. Taylor of Montreal is not a household name but near the turn of the last century, his concept helped sustain one of the first economic booms northern Ontario would experience. Dean Millar of Laurentian University and Electrale Innovation Ltd. may become one, especially in the “deep” mining sector.
Then Technology
The Year 1903 marks the advent of the great silver boom in Cobalt. With it came the demand for quick and reliable power required to run the mines ‘machinery. Within the mines, drilling was done by hand using compressed air.
In 1910, one of the most unique power plants in the world opened. This plant had no moving parts and used falling water to produce enough compressed air to operate the fifty operating mines in the Cobalt area.
To Taylor's creative mind, the explanation was one of physics, simple to him, not so to most of us.
When a mixture of air and water is compressed, the air separates and rises. Understandably, the air compresses, and not the water, because the molecules in a liquid are already very close together and are almost impossible to compress. Therefore a readily available, sustainable and “green” power source! He was ahead of his time.
Using this principle, Taylor determined that an efficient method to harness hydraulic air-compression would be to drop the air-water mixture through a sunken shaft to an underground chamber below the Montreal River. He designed the shaft in such a way as to allow the water to flow through, slow down while causing the air to compress. Some today would say “cool,” but it was very smart.
A dam was constructed on the Montreal River and a 9.5-foot shaft was blasted to a depth of 351 feet.
Air intake pipes at the top of the shaft introduced air into the water as it plunged down the shaft. As the water went down the shaft, it pushed against the air bubbles and pressurized them.
The deeper it went, the more the air bubbles were compressed. At the base of the shaft, the water mixed with air entered a 300-metre long, five-by-eight metre horizontal cavern at 90 degrees to the shaft. This slowed the water down, causing the buoyancy of the bubbles to take over.
All the bubbles rose to the top and joined together, creating a large body of compressed air. The air then entered a 24-inch diameter pipe that carried it to surface, while the water returned through a riser shaft driven by the head between the two reservoirs to rejoin the watercourse.
When there was more compressed air, than can be used by the mines, the excess air blows out below the surface of the Montreal River resulting in a geyser plume that often reached 65 metres in the air; beyond the average height of 32 to 56 m column of “Old Faithful” and “Fountain Falls.”
It was one of the most impressive sites around Cobalt and “environmentally friendly.” See this blow off on this YouTube video go to the Electrale website and scroll about halfway down the main page to the video; advance to the 5:44 mark; scroll further to the telling North Country Aerial photos of what was, so neat.
A fire, with unknown cause, destroyed the main building and debris partially blocked the intake pipes. The plant continued to produce compressed air for two, remaining mines as compared to the original fifty. (Presently there are no operating mines in Cobalt.) Studies commenced and the economic conclusion closed the plant permanently on December 24, 1981.
Now – Energy Efficiency
According to Dean Millar, a Laurentian University, this ingenious but long-forgotten technology for producing compressed air in the Cobalt mining camp will now play a role in reducing energy costs in the mining industry today Professor and President of Electrale Innovation. He resurrected the idea.
The original plant required no fuel, cost almost nothing to operate and ran continuously for 70 years with two brief maintenance interludes. According to Millar, an electricity bill today for a plant of that size would be $3 million to $4 million per year. He is convinced the technology is far superior to the electrically-powered air compressors currently used in the mining industry.
“Some of the work that’s done when you compress a gas isn’t used to pressurize it,” he explained. “Some of it ends up as heat, raising the temperature of the gas. That’s not very good. You want all the work that you’re applying to end up as pressure. If you can keep the gas cool somehow when you’re compressing it, you can make that compressor a lot more efficient. The Ragged Chute system increases the temperature of the gas, but the heat is transferred to the water, making it the most efficient gas compressor possible, concluded Millar.”
“A simple pipe going down an existing shaft with water from a mine’s water supply would more than suffice to produce the 2,000 cubic feet per minute of compressed air that a mine would require,” said Millar.
And here is the benefit as existing mines go deeper into the Earth’s crust. Millar’s hydraulic air compressor will replicate the technology used in the Ragged Chutes plant to demonstrate its effectiveness and applicability to 21st-century mining – not for the production of compressed air, but for cooling deep mines.
“Ragged Chutes used renewable energy (water from the Montreal River) to produce compressed air, but there’s another aspect of hydraulic air compressors that makes them very exciting even as a closed-circuit system with a pump,” said Millar. “The air is compressed at a constant temperature because the water cools it down. Then you allow the air to expand and when it expands, it cools down. If you cool it down in a certain way, you can achieve temperatures of minus 150 degrees Celsius, so you can produce a very, very cold high-speed jet of air that can be mixed with the mine’s ventilation air.”
The project has proven the cold air from the hydraulic air compressor can reduce the mine air temperature by a half to one degree Celsius.
“That doesn’t sound like a lot, but it’s actually very significant in a deep underground mining environment, according to Millar. Hydraulic Air Compressor (HAC) technology led to the construction of the HAC Demonstrator at Dynamic Earth.
"The prototype was unveiled June 22, 2017. On Sept. 12, 2018, at the International Mine Ventilation Congress in Xi’an, China, on behalf of Laurentian University, Dean Millar presented, “Performance map of the hydraulic air compressor installed at Dynamic Earth, Sudbury.”
"The HAC Demonstrator project at Dynamic Earth was very successful. It managed to bottom out many questions that had arisen as a consequence of our investigations before its construction. Many of these questions were embedded in the formulation of a mathematical model for the HAC process.
"Since then we have used the knowledge we gained to design modern larger-scale industrial HACs following the same concept. We were close to being commissioned to build at that scale for a gold mine around Kirkland Lake. The mine concerned was on care and maintenance while more exploration drilling was being undertaken.
"Unfortunately, the mine did not reopen fully and the concept was scrapped. We keep trying. In the meantime, we have been pushing on with the science. We are looking at ways to erode the system's capital cost (which is the main barrier) by making the systems shorter in height (we use more head in the circulating pumps). We are also exploring some interesting avenues in applying HACs to carbon capture and sequestration processes and in water and waste-water treatment.”
The Pipes
The Year 1903 marks the advent of the great silver boom in Cobalt. With it came the demand for quick and reliable power required to run the mines’ machinery.
Within the mines, drilling was done by hand using compressed air from a vast network of pipes. It was one of the most unique power plants in the world.
The Ragged Chutes (Montreal River) plant had no moving parts and used falling water to produce enough compressed air to operate the fifty operating mines in the Cobalt area. It remains an engineering marvel and is now being replicated. Google: “large-scale underground air compressor to supply deep mines.”
The pipes have a complementary history. There was an above-ground, 35 km pipeline transporting the compressed air to the mines.
Passersby could hear the ‘hissing” at some of the joins.
The high-quality steel (like our Henckel knives) was manufactured and transported from Germany, before the start of World War I. It is thought this same plant was then retrofitted to munitions and created the large artillery gun (howitzer) called ‘Big Bertha.’
In the early 1980s, Ontario Hydro removed the entire network, except for the remaining evidence. Maggie Wilson is President of the Cobalt Historical Society summarized its importance.
“The air pipeline was a remarkable engineering solution to the problem of providing economic power to the silver mines. The mines could operate equipment for a fraction of the cost, which of course meant more profits. For the citizens of Cobalt, especially the children, the pipeline was a way to get from home to work, or to a playground. Today, people shudder to recall how, as children, they'd cross deep open cuts by walking along the elevated transmission pipe.”
She recalled a heritage story, ‘Walk the Line,’ related to the pipe.
“Cobalt children walked the line to school and church because the warm pipes provided a dry kind of sidewalk.
"A Cobalt native, Johnnie Nadeau, once told me his sense of balance was probably developed running the pipelines as a child. In his adult years, Johnnie was an excellent steelworker and high rigger. He also related how his first after-school job included shovelling snow and filling the wood box at a popular brothel operated by “Silver Bust Simone.”
"As Simone’s residence bordered on the pipeline and many of her clients arrived by walking the line, Johnnie had always to clear the walkway to the pipeline first.”
I have walked the pipe, it is good for your balance, so can you.
See the map, evidence of the pipe is not on the Heritage Silver Trail.
“Yes, too far,” says Maggie. “ At one time organizers of the trail suggested including the pipeline, especially when the geyser was still active, but it never happened.”
A section of pipe is on display at Jack Koza Park, behind the Miner's Tavern, on Lang St. Other pieces of equipment are on display at the downtown headframe and next door to the mining museum.
The Heritage Silver Trail has been in the news, with the recent closure of two of the self-directed tour sites, see the Village Media Back Roads Bill story. Heritage has a price.
Think back and then ahead. There is no plaque for Charles Taylor or a street name or park commemorating his ingenuity, but as we go deeper into the Earth maybe there will be one for both him and Dean Millar.