Commemorations next week to mark the 50th anniversary of the Strongman Mine disaster are seen as the last significant opportunity for those with a living connection to gather together to remember the tragedy of January 19, 1967.
The underground gas explosion killed 19 men.
More than 200 relatives - including five of the six remaining widows of the 14 who lost their husbands at the time, and their children - have registered for the commemorations, to be held at the mine site in the Nine Mile Valley, as well as Runanga and the mass grave site in the Karoro Lawn Cemetery. Three of the widows still live in Greymouth.
"Their presence will be significant," said Strongman Mine historian and author Peter Ewen, who has compiled a new pictorial book specially commissioned for those attending the reunion.
Strongman was a "flagship" State mine and employer for the Greymouth area and what happened there needed to be remembered, particularly in light of subsequent events including the Pike River Mine disaster, Mr Ewen said.
"It's part of West Coast history. Strongman was a significant employer for 60 years and really the driver of the economy around here. It was a flagship."
A number of the men involved in the recovery of the victims of the 1967 disaster would also be attending.
"They realise the significance of 50 years. No one's going to be around in a hundred years so this is their commemoration," Mr Ewen said.
On that disastrous day in 1967 teams of Mines Rescue volunteers went back into the mine after the explosion, pulling out 15 of the bodies of their colleagues, with a further two bodies recovered just over three weeks later; the remaining two could not be found and were left entombed in the mine.
"It's important that we remember these things because if we forget them it comes calling again - it repeats itself," Mr Ewen said.
The new pictorial book Pictures Past - Strongman's Men and 1967 Remembered, brings together many pictures used in a previous book by Mr Ewen on the disaster, along with dozens of new images that have emerged of the disaster aftermath and funerals, including film stills - with new material coming to light as late as yesterday in the form of colour slides.
The book represents many months of research and careful collation after the Strongman 50th anniversary committee secured sponsorship from within the community to produce the book, thereby enabling all those registered for the commemorations next week to receive a copy.
Many of those registered for the event are returning from across the Tasman as well as throughout New Zealand, and Mr Ewen said it would be the last time anyone connected with the events of that day 50 years ago would probably gather together in a formal way.
Strongman 50th Anniversary Committee co-ordinator Rose Green said registrations had closed but members of the public would be able to attend the public parts of the weekend including a public ceremony at the cemetery at 10.04am on Thursday to coincide with the moment the mine exploded in 1967.
On Friday night the programme will move to the Runanga Workingmen's Club from about 5pm, then on Saturday morning groups by special arrangement will be taken up to the Strongman Mine portal to lay wreaths.
After lunch back in Runanga an old-fashioned sports day will be held.
Mrs Green said this was particularly appropriate given the camaraderie and culture among the miners of the day, and the sports day activities were a reflection of those men's interest at the time including coal shovelling, wood chopping and a harrier run.
She said the remaining widows and their children, along with those who risked their lives to recover the bodies, would be at the heart of the gathering.
"It's a sad time but it's a time of remembrance because in the next 50 years there's going to be nobody around."