A Quebec machine equipment manufacturer is offering a $20,000 reward to recover a 10-tonne piece of metal equipment stolen from its lot this summer.

Marmen built the cylindrical piece for a Japanese company and was set to ship it overseas last week when an employee discovered it was missing from the Trois-Rivières lot.

The equipment, used to produce large plates of aluminum, had been sitting in storage for three months, said Marmen president Pierre Pellerin.

The company isn't sure when it was stolen but believes the theft occurred between Aug. 9 and 14.

The thieves managed to get past security guards who patrol the company's headquarters 24 hours a day.

The piece was probably stolen because of the value of the metal, which could run into the millions of dollars, Pellerin said.

It will take the company about a year to replace the part.