Eight years after an explosion killed 29 men in New Zealand’s Pike River mine the government has announced it will stage a manned re-entry to reclaim the bodies, following years of pleas from family members.

Re-entry is scheduled for February and work is already underway to prepare the main drift entrance for the mission, including pumping methane out and pumping nitrogen in.

In the weeks before Christmas other preparatory work such as drilling bore holes will begin, and the 30-metre seal to the mine entrance will be broken in February next year, allowing miners access to the drift.

“To the Pike River families and to New Zealand – we are returning,” said Justice minister Andrew Little, who has overseen the re-entry plan.

“There is always uncertainty in projects such as this … there is a lot that we do not know and will not know … till we confront it underground. This will require agile thinking, the courage of all to say no if we are uncomfortable … and knowing when to call it quits,”

In November 2010 two explosions tore through the Pike River Mine near Greymouth on the South Island’s west coast, killing the miners inside, including two Australians and two Britons.

Dozens of family members have campaigned for years for a re-entry to retrieve the bodies and investigate what caused the explosion. On Wednesday they expressed their relief at finally making headway, in emotional scenes at Parliament House.

Anna Osborne, who lost her husband Milton in the mine, said the manned re-entry was an historic victory for the families, and would allow all New Zealanders to find our what really happened at Pike River, and make workplaces safer all around the world.

“This is a victory for the little people in New Zealand who feel like sometimes it is too hard to carry on and win a battle because there are so many roadblocks being put in the way. You need to be that squeaky wheel, you need to be that voice,” said Osborne, crying.

“If you believe in something hard enough and long enough, you’ll get people to listen … for our men, we couldn’t just let things lie.”

Families and supporters staged large protests in 2016 when the mine’s owners attempted to permanently seal the mine, entombing the men inside.

In June, deputy prime minister, Winston Peters, said he was so confident of the safety of re-entering Pike River that he vowed he would personally be the first to do so.

Before his career in law and his four-decades in parliament, 73-year-old Peters is understood to have spent a stint working in Australian mines.

Little has has also volunteered to be the first man to enter the mine, saying: “He [Peters] and I might be racing each other for it.”

Three options for re-entering the mine were presented in an October report, following explorations by a robot, and nine months of consultation with police, mines rescue,the department of conservation and overseas mining experts.

With the assistance of independent advisor Rob Fyfe, Little has decided on option two; entering the mine via the main drift access tunnel.

“Safety of everyone is fundamental for re-entry, as is the care needed to forensically examine what happened at Pike River to ensure it never happens again,” said Little.

“The families have shown extraordinary patience and tenacity, and their contribution has been crucial.”

Police have said they will now re-open their investigation into what happened at Pike River and forensically examine the bodies..

Little said the cabinet has approved a boost to the re-entry budget this week, bringing the total budget to NZ$36m (£19m).