(Adds quotes, details, output levels)
By Erwin Seba
HOUSTON, July 30 (Reuters) - Exxon Mobil Corp has pulled together a group of experts at its sprawling Beaumont, Texas, refinery to do more detailed studies to add a third crude distillation unit that could make it the top fuel-making plant in the United States, sources familiar with the matter said on Thursday.
The formation of the group indicates Exxon is moving closer toward expanding the 334,600-barrel-per-day plant. Reuters previously reported the company was eyeing a plan to lift capacity at Beaumont to as much as 850,000 bpd.
Exxon declined to comment on the formation of the group, called "Crude C" for the proposed third crude distillation unit. The expansion would cost several billion dollars and take several years.
"The Crude C group is studying how to build the new crude unit and where to put it," one of the sources said. "They have offices in the refinery and are running around in their own trucks."
Late last month, the United Steelworkers union representing workers at the refinery agreed to a six-year contract with Exxon. That is two years longer than a national contract agreed to by U.S. refinery owners in March.
Sources familiar with Exxon's plans have said the company lobbied hard for the longer pact to assure no work stoppages while construction to expand the refinery is under way. (Reporting By Erwin Seba; Editing by Terry Wade and Lisa Von Ahn)