Christopher Reid died last summer when he was crushed by a four-tonne mobile conveyor belt at PotashCorp’s mine in Allan. Sask.

The 28-year-old had been working underground for six months. The first anniversary of his death is tomorrow.

CBC News has learned the results of an internal PotashCorp investigation into his death, and the sweeping changes to policy and practice it triggered in the following months.

"There’s a whole bunch of things that we all did wrong," said Ron St. Pierre, who heads the union.

"We failed as a company, and we likely failed as a union."

Reid worked as a part of a three-man crew. He helped run a mobile conveyor belt called a "mineveyor" that connected to the sixty-tonne boring machine used to mine the potash.

St. Pierre says the investigators tried to re-construct Reid’s last moments.

"He was between the mineveyor and the wall, nowhere to go, and the wheel caught his clothing or his boot, we’re not sure how that happened, but it caught him and dragged him underneath the mineveyor," he said.

The mobile conveyor stretches more than a hundred metres and is broken into segments so that it can follow the borer. Reid worked at the front, and his partner worked at the back and witnessed his death.

Bill Johnson is with PotashCorp. He says the company made changes to the mineveyor after the accident.

"We made some adjustments to the mineveyor equipment and installed some emergency stops onto the mineveyor equipment itself," he said.

"It would be a switch that would stop the machine from operating."

Being able to shut down a four-tonne machine in an emergency is important. But St. Pierre says the company didn’t have to install a new emergency switch.

Rather, it just had to fix the one that was there already.

"It quit working and nobody fixed it," he said.

"It was inconvenient, at times it would shut down the machine when we weren’t intending to do that … it was more convenient to run that way."

But Johnson says the emergency stops on the mineveyor were tested after the accident and found to be in good working order.

"In response to recommendations from this investigation, some modifications were made to the emergency stop system, but all emergency stops on the mineveyor were operational and in good working order," he said.

The company eventually adopted 17 recommendations.

St. Pierre said there were mechanical problems with the mobile conveyor that forced Reid into an unsafe position. One of the switches on the unit was jammed, so the machine was turning when it shouldn’t have.

The fatality report also recommended some larger changes.

Workers are now outfitted with radios so that they can communicate over the thousand-horsepower machinery. The labelling and locations of the control boxes on the conveyors is now standardized.

And any changes to the equipment, or practices, are updated in the training manuals.

The province’s chief mining inspector has finished his report into the accident. It’s still with the Occupational Health and Safety Branch..