Mbombela - Trade union Solidarity on Friday claimed it had proof that the Lily Mine tragedy could have been prevented."We decided that the information will be handled as confidential while the investigation is on-going. This way we might be able to avoid closing the mine, that will lead to hundreds of workers losing their jobs," secretary general Gideon du Plessis said in a statement.Making the information public would have slowed down efforts to find the three workers still trapped underground, he said.The union cancelled a press briefing it had scheduled for Thursday after meeting the mineral resources department’s acting director general, David Msiza, and the mine’s owner, Vantage Goldfields, to discuss the cause of the disaster.Du Plessis said someone had been negligent and the time had come to bring the guilty parties to book.Vantage Goldfields spokesperson Coetzee Zietsman said Solidarity had no members working at Lily Mine, near Barberton, Mpumalanga."We were quite shocked when we heard about this media briefing without having the details about what was to be discussed," Zietsman said.Part of the coal mine collapsed on Friday, February 5. Three employees - Yvonne Mnisi, Pretty Nkambule and Simon Nyerenda - were in a lamp room housed in a shipping container on the surface. It disappeared into a sinkhole about the size of a rugby field and was buried under tons of rock.Seventy-five miners who were underground at the time escaped unhurt and made it to safety.Two subsequent collapses at the mine have halted all attempts to find the three. Recovery attempts would only resume in six months, once another entrance to the deeper levels had been designed and built.