Federal energy authorities have slashed by 96% the estimated amount of recoverable oil buried in California’s vast Monterey Shale deposits, deflating its potential as a national “black gold mine” of petroleum. Just 600 million barrels of oil can be extracted with existing technology, far below the 13.7 billion barrels once thought recoverable from the jumbled layers of subterranean rock spread across much of Central California, the U.S. Energy Information Administration said. The new estimate, expected to be released publicly next month, is a blow to the nation’s oil future and to projections that an oil boom would bring as many as 2.8 million new jobs to California and boost tax revenue by $24.6 billion annually. The Monterey Shale formation contains about two-thirds of the nation’s shale oil reserves. It had been seen as an enormous bonanza, reducing the nation’s need for foreign oil imports through the use of the […]