A New Zealand coal mine that has been sealed shut since 29 workers were killed in an explosion more than eight years ago reopened Tuesday.

Mining experts entered the Pike River Mine to begin a search for the men’s remains and any evidence that could explain what caused a buildup of flammable methane gas that is blamed for the November 2010 disaster that initially trapped 31 miners. Two of the workers managed to escape after the explosion.

Prime Minister Jacinda Ardern heeded the demands of the families of the 29 dead workers to reopen the South Island after she took office in 2017. Andrew Miller, the special minister appointed by Ardern to lead the reentry efforts at Pike River said, “New Zealand is not a country where 29 people can die at work without real accountability. And that is why today we have fulfilled our promise.”

An official inquiry determined that mine’s operators had allowed the miners to operate in unsafe conditions. Labor violation charges were filed against Peter Whittall, the mine’s chief executive, but were later dropped, and no criminal charges were filed in connection with the tragedy.