Steel company Gerdau said Monday that it will invest $50 million in its St. Paul mill to increase production capacity.

The company will replace the mill's continuous caster, crucial machinery in a steel plant. The new caster will allow Gerdau to increase production capacity for special bar quality steel by 100,000 short tons, and improve steel quality levels.

"This investment demonstrates our company's commitment to the St. Paul area and helps us remain our customers' supplier-of-choice for years to come," Guilherme Gerdau Johannpeter, president of Gerdau Long Steel North America, said in a news release.

The company expects to break ground on the caster project in 2012's second quarter, and expects its completion by early 2014, subject to regulatory approvals.

Brazil-based Gerdau bought the former North Star Steel mill in St. Paul in 2004 from Cargill Inc. The 47-year-old mill has 370 employees.