(Updates with details from conference call)
June 18 (Reuters) - PBF Energy Inc agreed to buy the 189,000 barrel-a-day Chalmette, Louisiana, refinery for $322 million from Exxon Mobil Corp and Petroleos de Venezuela SA, marking the New Jersey-based company's Gulf Coast debut.
PBF shares jumped 17 percent to $31.04. The transaction is expected to close by year-end and boost 2016 earnings by 20 percent.
The purchase marks an expansion beyond the eastern United States by the independent oil refiner, a move long awaited by investors. PBF had looked at the Texas City Refinery in 2011, while the plant was owned by BP Plc.
The Chalmette refinery "has tremendous hardware capabilities," said Paul Davis, senior vice president of PBF. The plant is equipped to run crude from around the world, he said.
PBF will maintain a supply contract with Venezuela, but will look "quickly" to widen its crude slate, CEO Tom Nimbly said.
The company will also look to increase the refinery's throughput of light-sweet crude from about 40,000 bpd to up to 60,000 bpd, Nimbly said.
The refinery runs both light and heavy crudes, with about one-third of its throughput coming from Venezuela, according to the U.S. Energy Information Administration.
In the first quarter, the refinery imported an average of 73,000 bpd of crude from Venezuela, or about 10 percent of all U.S. imports from the country, according to the EIA.
The cost per complexity barrel, a key metric in evaluating refinery sales, is roughly $160, the company said, less than half of the average valuation of the past 12 years. That means PBF paid less for the ability to convert heavy grades of crude oil to products like gasoline.
The Chalmette plant, built in 1915, sits on 400 acres (160 hectares) of a former plantation in Louisiana and is the largest employer in St. Bernard Parish, with about 1,000 employees and contractors, according to Exxon.
Chalmette is PBF's first refinery purchase since 2011, when the company bought the 160,000 bpd Toledo, Ohio, plant from Sunoco Inc for $400 million.
In 2010, it bought Valero Energy Corp's 160,000 bpd Paulsboro, New Jersey, refinery for $360 million and Valero's 182,200 bpd Delaware City, Delaware, plant for $220 million.
"I have been involved in many refinery acquisitions over the past 30 years. This certainly is one of the best from both an earnings and a value perspective," PBF Executive Chairman O'Malley said in a conference call Thursday.
PBF is O'Malley's third U.S. independent refining company focused on buying plants at low prices.
The company can move some purchased assets into a master-limited partnership, which makes the deal appealing, said Roger Read, an analyst with Wells Fargo.
Hit by a recession and lower oil prices, Venezuela's government is raising money to cover hefty debt payments and spending ahead of a year-end parliamentary election.
PDVSA also owns three U.S. refineries and 48 oil terminals through its Citgo unit. Venezuela put Citgo on the block in a separate transaction a year ago, but canceled the auction in January. (Reporting by Anet Josline Pinto in Bengaluru; Jarrett Renshaw in New York and Kristen Hays in Houston; Editing by Marguerita Choy, Jessica Resnick-Ault and David Gregorio)