At least 20 miners in Zimbabwe have been trapped underground after a shaft collapsed, state media reported on Thursday.The incident occurred overnight at the Globe and Phoenix gold mine in the central town of Kwekwe, around 200km west of Harare. Operators were first alerted early Thursday after the miners failed to surface at the end of their shift."We received the news about the unfortunate incident a few hours ago and we are running around coordinating a rescue mission," the chair of provincial civil protection unit, Fortune Mpungu, told The Herald newspaper.Police were not immediately available for comment. Mining is a major source of foreign currency for Zimbabwe. The southern African country is home to vast gold and mineral reserves, including diamonds and platinum. The Globe and Phoenix was originally named originally named King Solomon's Mines. It once produced the world's richest gold ore.