CALGARY — For the Mullen Group, acquisition trail continues to lead right to Alberta’s booming oil patch, as the truckload and energy services giant bought three more western trucking companies late last week.

Mullen, which grew to become Canada’s third-largest for-hire carrier when it merged with Producers Oilfield Services earlier this month, announced it was buying three small, unnamed carriers for a reported $31 million, according to Canadian Press.

The carrier didn’t name the three firms, except to say that they include a Saskatchewan-based crude oil transporter, a heavy hauler from Calgary, and a flat-deck carrier out of Edmonton, CP reports.

Chairman and co-chief executive Murray Mullen told analysts that the carrier is operating at full capacity with the assets it currently has, and the recent acquisitions should allow the company to increase volumes mainly in the energy-rich Northern Alberta sector.

Mullen has followed the path of other income trusts like TransForce in growing via acquisition and consolidation.

On Feb. 15, Mullen and Producers announced that their respective boards have approved a merger agreement worth close to $1 billion. Prior to the deal, Producers sat at #17 on Today’s Trucking’s 2006 Top 100 carrier list. The merger, if approved by shareholders and regulators, would put the Mullen Group at #3, behind TransForce and Vitran.

Executives from both companies met over the weekend to identify common efficiencies.

Producers was originally spawned from Mullen, when in 2001 Mullen spun off a logistics business called Moveitonline, which was bought by another company called Patch Point Enterprise. Moveitonline changed its name to Producers Oilfield Services in 2004.

Over the last year, Mullen has bought oilsands driller Schmidt Drilling, B.C. trucking firm Tenold Transportation, and the remaining 55 percent of Winnipeg-based Payne Transportation.

Most recently, Mullen purchased almost all the outstanding shares of Pe Ben Oilfield Services Ltd. after renegotiating a hostile takeover, which Pe Ben finally agreed to.

— with files from Canadian Press