At least eight miners were killed following an explosion at a carbon mine in Colombia, the National Mining Agency has said.The blast occurred on Friday in Pueblo Viejo de Cucunuba, 90 km from capital Bogota, the Agency said on Saturday, Xinhua news agency reported."The official report is of 14 people affected by the incident including "one injured, eight killed and five missing," the National Mining Agency posted on its Twitter account on Saturday.The blast was blamed on a "methane gas explosion".Initially, authorities reported two deaths late Friday and 11 people missing.Around 35 rescue workers and seven engineers were working round the clock to locate the others, news network Caracol said on its website.Coal mining is a major industry in Colombia, which produced a record 90 million tons of the fossil fuel in 2016, said Caracol.