Unlocking Oil - With Scores of specially designed machines like this big, mobile drill, the U.S. Bureau of Mines believes it has licked the cost problem which long has blocked the way to effective conversion of oil shale rock into usable oil. Improves mining methods and better extraction processes developed in experiment work here are though to have insured the nation's gasoline supply for centuries to come, regardless of what may happen to the liquid petroleum reserves. The drill is shown working in one of the 60-foot square rooms which now Honeycomb a Portish of a vast plateam which contains billions of barrels of oil locked in shale. September 15, 1949. (Photo by AP Wirephoto).