* Surgut equity structure has been shrouded in mystery
* Company is Russia's No. 3 oil producer
* Has $30 billion cash pile (Adds details, background)
MOSCOW, Dec 19 (Reuters) - Workers at Russian oil firm Surgutneftegas own a large stake in the business, President Vladimir Putin said on Thursday, lifting some of the uncertainty over who controls the country's No.3 oil producer and its huge cash pile.
Run since 1984 by a Vladimir Bogdanov, 62, Surgut has kept its ownership structure shrouded in secrecy and has given minority shareholders no clues about plans for its $30 billion of cash - twice the size of Moscow's recent support package for neighbouring Ukraine.
Bogdanov said in 2000 that management and its allies controlled up to 70 percent of the business, but since then has been tight-lipped.
"Surgutneftegas is an absolutely private company ... A large amount of shares is owned by workers' collectives," Putin said during an annual news conference, in comments that appear to suggest the firm's ownership structure has changed little.
Market players have long-speculated that Surgut might end up in state hands or be bought by some Kremlin-friendly oligarchs, and the years of silence about its ownership fuelled talk that a change in influence might have taken place.
Surgut's market capitalisation is $36.6 billion, close to the value of its cash pile and highlighting investors uncertainty over the business.
The company is based in the Siberian town of Surgut and pumps around 1.2 million barrels of oil per day (bpd) out of Russia's total of 10.6 million bpd.
According to official documents, Siberia-born Bogdanov owns a 0.3 percent stake in the company and is its largest shareholder, while the group itself is split among roughly 34,000 unidentified stakeholders.
Russia's oil sector is dominated by state-controlled Rosneft , which turned into the world's largest public oil company by output this year after taking over smaller rival TNK-BP for $55 billion.
Rosneft now pumps an average 4.2 million bpd, or 40 percent of Russia's total. (Reporting by Katya Golubkova; Editing by Steve Gutterman and Mark Potter)