Ten big holes have already been drilled through the concrete wall at the Pike River mine ahead of the re-entry on Friday.
Newshub can also reveal the three miners who will take the historic steps inside.
Twenty-nine new crosses were put up and painted by family members like Rowdy Durbridge on Wednesday. A mining helmet was placed on each one.
On Friday, the mine will be re-entered, eight-and-a-half years since the explosion. Dinghy Pattinson, who is in charge of re-entry, said he'll be the first to enter the mine.
"I'll lead the team," he told Newshub.
Friday is about getting past what is known as the 30-metre mark.
"We've been further before, but that was meant to be the end - that's changed. So yeah it will be a big step we're taking," Pattinson said.
Alongside Pattinson will be miner Kirk Neilson and geo-technical engineer Rick Lee. The latter will be checking the structural safety - and making history.
"I'm excited for the families, they've battled hard," Lee told Newshub.
The mine has been filled with nitrogen - so the methane is inert and can't explode. Oxygen is now being pumped in to where the men will work.