Mining potash above ground: how the new Bethune mine works

With a new $4.1 billion solution potash mine by Bethune nearing completion, an expert is differentiating between this type of mine versus conventional mining.

“When most people think of potash mining, they think of people underground and the big mining machines,” revealed Sam Farris, VP and general manager of operations with K + S Potash Canada’s Legacy Project.

No, workers don’t emerge with dirt-covered faces while squinting at the sunlight at this massive facility. Instead, Farris explained this form of mining is controlled from the surface.

It all starts with a water-based solvent that’s injected deep underground into caverns, roughly 1.5 kilometres into the earth. The solvent then dissolves potash and the sodium chloride (salt) along with it. That produces a brine, or a salty water. That mixture is then pumped back up to surface to the processing plant.

It then goes through two main steps.

“We heat that water up and boil off water in our large evaporators,” explained Farris.

As that happens, the sodium chloride comes out of solution as a byproduct. That same solution is then cooled in five different steps.

“As we cool it, potash comes out of solution.”

That’s their final product which is sized through either compaction, screening or both. It’s then stored in one of two massive warehouses. One is about the size of a football field and can hold roughly 100,000 tonnes of potash. Farris said that’s a month’s worth of capacity. A smaller warehouse for industrial potash can hold 40,000 tonnes.

A total of 2.86 million tonnes will be produced beginning in 2023, estimated Farris. By the end of 2017, the facility will have the capacity of producing about two million tonnes.

Of course, potash is one of Saskatchewan’s biggest industries. Farris admitted there aren’t as many people familiar with how a solution potash mine like this operates compared to the past. He said there’s only one other facility like this in the province to his knowledge.