TEMPO.CO, Jakarta - Dwiyanto Joko Suprapto, a geomethanics expert from Diponegoro University, said that the Big Gossan tunnel collapse is something that should have been known in advance. He argued that any underground tunnel or mine has a stand-up time or an operational life.
"So, since the initial planning, the team should already know how old of an underground tunnel or mine is," Dwi told Tempo, Sunday, May 26.
He said cracks are a natural occurrence that can be monitored using an extensometer, a device that detects and measures ground movement and shifting. "It is used to provide early warnings of avalanches or collapse," he said.
President and CEO of Freeport-McMoRan Copper & Gold Inc., Richard C. Adkerson, said that the Big Gossan collapse occurred suddenly. He said that he had never calculated the probability of the disaster.
Nevertheless, he claimed that the underground training facility had high security and safety standards. According to Adkerson, in its 30 year of conducting mining operations, this kind of incident never happened before.
"We never expected this could happen after looking at the track record of our safety standards--which is the best compared to other mines," Richard said in a press briefing last Thursday.
AYU PRIMA SANDI