A worker from a mine in West Papua says the tunnel collapse that killed 28 people was caused by human error.
The allegations come as the Indonesian government has ordered the company to halt production until its investigation report is in.
It has already made several recommendations to the company, but workers claim that is not enough.
Alex Perrottet reports:
The US-based Freeport McMoRan receives most of its income from one of the world's biggest mines in the remote province of Papua. It reopened the mine last week, but employee and union-member Darmawan Puteranto says it's not good enough to continue operations without a bigger commitment to improving conditions.
"It's very very extreme here, because 28 persons dying, it's not a small number, it is a big number. And with the Indonesian Government, the sanctions should be very hard."
He says he is convinced there was human error involved in the collapse. He says workers who sat in the classrooms regularly reported poor conditions and said they could hear rocks falling.
I think all of the employees are worried about their working conditions right now. They are not sure anymore about their safety. I think the management should improve or modify the safety programme to avoid the same thing happening tomorrow.
Freeport's CEO, Richard Adkerson, was not available for comment and the company has made it clear the accident in the training facility was well away from their production area. But on Friday a truck driver died in a separate incident within the mine area. Mr Puteranto says pay is also an issue. He says workers at the mine earn a fraction of what colleagues earn overseas, and a tiny portion of the company's profits. But the vice chairman of the Indonesian Mining Association Tony Wenas says the comparison is unfair.
You cannot compare apples with oranges. Even though it's the same mining industry we cannot compare. The workers are not shareholders, right? It's not a sharing of profit because they are not going to also bear the loss.
He says workers don't suffer the effects of the companies' fluctuating market value, but looking after the workers should be a priority.
We expect that all mining companies put a very high standard on safety because our employees are our main asset. And, I mean, when I say 'companies', I mean all companies in Indonesia.
Mr Puteranto claims he is the only employee that has joined the union, whose membership is dominated by contractors. He says management doesn't prohibit staff from joining, but they are intimidated.
A lot of staff is afraid to join the union because they're afraid it will affect their career, because the right to join the union is a human right, you know?
Tony Wenas says the whole industry in Indonesia needs more legal certainty with greater regulation. He says Indonesia ranked at the bottom of 96 countries in a recent policy-potential index and says that's a wake-up call for the government.