Twenty miners at this Chinese coal mine have been confirmed dead after an accident early on Tuesday.br br Authorities say the miners were killed when a cart lifting them to ground level slipped in a pit.br br 34 miners were in the two-cart carriage.br br Authorities said the carriage was designed to carry just 10 passengers.br br Of the 14 injured, three received serious injuries.br br China has the world's deadliest coal-mining industry.br br Safety improvements have reduced the number of deaths in recent years, but safety rules are often ignored.