Not Your Grandfathers Mining Industry, Nova Scotia, Canada

Muskrat Falls Hydro

Mining makes renewable energy possible!

Usually when we say that we are referring to metals like copper and lithium used to generate, transmit and store energy. But renewable energy also needs rock. In fact, over one million tonnes of rock helped build the Muskrat Falls hydro project.

The Muskrat Falls hydroelectric development on the lower Churchill River in Labrador generates renewable energy for Newfoundland and Labrador and Nova Scotia.

The powerhouse and spillway for the Muskrat Falls project were built with 560,000 cubic metres of concrete. That is enough concrete to pave a one-metre wide, 10-centimetre-thick path from St. John’s to Vancouver.

Rock aggregate makes up about 80% of concrete so about 450,000 cubic metres of aggregate (725,000 tonnes) helped build the powerhouse and spillway.

An additional 200,000 cubic metres of concrete were used in building two dams, requiring about another 250,000 tonnes of aggregate.

Rock also contributed to the project in other ways. For example, rock berms (ridges) were built over the undersea cables that transmit the power from Labrador to Newfoundland and on to Nova Scotia. The berms protect the cables from marine vessel traffic and environmental conditions.

In total, over one million tonnes of rock helped make the renewable energy project possible.

Mining and quarrying contributed to the project other ways, too. For example, approximately 4,500 transmission towers, mostly made of steel, help carry the electricity through Labrador and Newfoundland. Steel is mostly made of iron and carbon, and the carbon is derived from metallurgical coal, the type of coal mined at Cape Breton's Donkin mine.

The Labrador-Newfoundland transmission system also includes six million metres of wire, enough to stretch between St. John’s and Athens, Greece. Wire is mostly made of copper or aluminum.

Nova Scotia’s main interest in the project is the Maritime Link, two subsea cables that carry hydro power across the Cabot Strait to this province.

Each cable measures approximately 170 kilometres and weighs 5,500 tonnes – combined, the two cables weigh more than the Eiffel Tower. The two cables are the longest submarine electricity connection in North America.

Each cable is ten centimetres in diameter (similar in size to a two-litre soft drink bottle) and has 14 layers. The centre, and about one-third of the cables’ thickness, is a copper wire that carries the electricity. The other 13 layers protect the copper.

That is a lot of numbers but the point is that none of this would be possible without mining and quarrying.

People who support renewable energy but oppose mining need a rethink – mining makes renewable energy possible.

So, how does a hydro plant like Muskrat Falls generate electricity?
Hydro projects build a dam on a large river that has a large drop in elevation. The dam stores lots of water behind it in the reservoir. Near the bottom of the dam wall there is a water intake.

Gravity causes water to fall through the sluice/floodgate inside the dam. At the end of the sluice is a turbine propellor, which is turned by the moving water. The shaft from the turbine goes up into the generator, which produces the power. Power lines connected to the generator carry electricity to users.

The water continues past the propellor and exits the plant into the river.