The operators of a mine where 24 workers died in a massive blast last week had been ordered by inspectors as recently as last month to improve safety conditions. Officials from the safety inspection bureau of Yunnan province said the office had issued 11 specific instructions to the operators of Jizuo Mine in Huaping county between April 8 and last November to improve the ventilation, Xinhua reported. A gas explosion ripped through the mine last Wednesday afternoon, killing all but three of the miners, who only survived because they were working near the exit. By Friday evening, rescuers had recovered all 24 bodies from the shaft. The incident followed a week-long spate of accidents that claimed the lives of more than 100 miners across the mainland. The director of the Yunnan Provincial Safety Inspection Bureau, Zhou Shigui, was yesterday quoted by Xinhua as saying that long-term neglect of safety measures had led to the blast. Investigators said the immediate cause was miners using an old and dangerous drilling technique which did not allow for sufficient ventilation of the mine. As a result, underground gases gradually built up in the shaft to dangerous levels. The investigators' report said that officials had told the mine operators to stop using the technique. They said that if the mine had taken steps to meet the government's safety standards, the blast would have been avoided as the mine was located in a low-lying area which rarely saw explosions. According to the report, Huaping county is among the nation's top coal-production regions. All mines there have been temporarily shut down following the blast. Mining is one of the mainland's most dangerous industries. The State Administration of Work Safety recently reported that in the first three months of this year, there were more than 611 mining accidents reported, claiming 1,090 lives. The majority of the deaths were in small, illegal mines.