Lack of maintenance caused roof collapse at Saskatchewan potash mine: inspector

COLONSAY, Sask. – An inspector says a delay in maintenance caused the roof of a building to cave in at a potash mine southeast of Saskatoon last winter.

Neil Crocker, Saskatchewan’s chief mine inspector, says an engineer assessed the building at Mosaic’s Colonsay (kah-LAHN’-say) operation before the collapse last February.

He found two rings that hold the building together were in bad shape.

He had the worst of the two repaired right away and there were plans to fix the other ring in a couple of years.

Crocker says the engineer was wrong about how long he had to fix the second ring.

The collapse occurred in the thickener building where clay is separated from a salty solution known as brine.

No one was hurt when the roof tumbled.

Mosaic has introduced stricter inspections for all of its buildings worldwide. The new approach includes assessing the risk of a failure as well as what happens if it occurs. Inspectors assign each building a colour following an inspection. Red means immediate repairs are needed or the building must be closed.

Under the new system, the thickener building would have been given a red designation, Crocker said.

“In this case, the (building) would not have passed the criteria and they would have had to shut the building down.”

Crocker said the structure where the roof collapsed is still being repaired and rebuilt.