LUSAKA, May 18 (Xinhuanet) -- Four miners have been confirmed dead in a copper mine accident in Zambia's Copperbelt province Wednesday, as their bodies have been retrieved from underground by rescue workers, the official Zambia News Agency said.

    The accident occurred at around 7:15 a.m. local time (0515 GMT)Wednesday when a cage full of miners plummeted down a shaft at the Mopani Copper Mines (MCM) in Mufulira, about 450 km to the north of Zambian capital Lusaka.

    James Muluka, acting head of mine safety at MCM, said the rear sliding door of the cage flung open whilst in motion in unexplained circumstances.

    It is suspected that overloading might have caused the accident as the cage with a capacity of 66 carried more than 100 miners on the fateful day.

    The report said several workers were tossed out of the cage and later crashed by the cage.

    It indicated that the cage eventually landed at the 500 meter working level, but said some bodies could still be trapped at the lowest 1,465 meter working level.

    The exact number of casualties are yet to be released since it is difficult to determine the number of victims as what was picked up from the bottom of the shaft were piles of pieces of human flesh.

    The report said local police had a tough time to control angry relatives who besieged the mine and smashed a police vehicle.

    The mine premise has since been sealed off by police.

    Earlier, Mines and Minerals Development Minister Kaunda Lembalemba told Xinhua that he is still waiting for details including casualty figures from mine safety inspectors at the site.

    Zambia, the world's fourth largest copper producer, has recently witnessed an increasing number of mine accidents, as production is being driven up by higher prices and strong demands on the international market.

    In April, explosion at a mining explosive factory killed over 40 workers in Chambishi, also in the Copperbelt province.

    Minister Lembalemba said the government is making efforts to improve mine security, including the recruitment of more inspectors, but he added that it is the mining companies who have the biggest responsibility looking after the security of their workers and assets. Enditem