Businessman, Silver Tycoon. Born in Ireland and coming to the United States in 1845, O’Brien went to California following the Gold Rush in 1849. Finding little success at mining, he settled in San Francisco where he joined with James Flood to open the Auction Lunch Saloon in 1854, which they operated until 1866. With many of their clients coming from the nearby San Francisco Mining Exchange, the two men soon learned about and picked up tips on mining stocks on the Nevada silver mines. Forming a partnership with fellow Irish miners James Fair and John Mackay, Flood and O’Brien left their saloon to become stockbrokers and in 1869 they took control of the Hale and Norcross Mine. In 1871 they took control of the Consolidated Virginia Mine, which had been considered by many as having little silver. In 1873, the mine struck the largest silver deposit ever discovered, becoming known as the “Big Bonanza,” and earned the four men the titles as the “Bonanza Kings.” Following his death from illness at the age of 52, he was originally buried in San Francisco’s Calvary Cemetery. He was later moved to Holy Cross Catholic Cemetery in Colma following the eviction of cemeteries from San Francisco city limits. (bio by: G.Photographer)