Ben Rockhouse's family is holding what will be one of the final memorial services for the 29 men killed in the Pike River blast almost two years ago.

The former Christchurch man and 28 fellow workers died after the underground West Coast coalmine exploded on November 19, 2010.

His brother, Daniel, managed to escape and dragged the only other survivor, Russell Smith, about 1.5 kilometres along the mine's tunnel to safety.

Ben's grief-stricken family has resisted a memorial service until now, determined to wait until his remains are returned home.

However, the mine's new owner, state-owned enterprise Solid Energy, announced several months ago that body recovery was extremely unlikely.

The men remain entombed in the mine deep in the Paparoa Range, inland from Greymouth.

"We have acknowledged with Solid Energy's announcement that it's time to let Ben's friends say goodbye to him in an appropriate way and to help them to move on with their lives," said Ben's father, Neville Rockhouse.

It also was to thank the thousands of people around the world for their huge support since the tragedy, he said.

The service would be held on Saturday at 11.30am at Ben's former school, Avonhead Primary School in Christchurch, with hundreds expected to attend, including many friends returning from overseas.

Neville Rockhouse said the family chose September 1 for the memorial service because it symbolised new growth and hope as the first day of spring.

"This is not like a funeral, it's a celebration of his life. A funeral will happen when and if we get his remains back."

The service would reflect Ben's fun-loving nature, such as having his gorilla suit on display that he would often wear at parties.

While the last almost 22 months had been tremendously sad, it had also brought their family closer together, Rockhouse said.

But it was also filled with regrets. At the time the mine exploded, Neville Rockhouse was its safety and training manager and believed it was a safe mine.

Ben, his youngest son, had been studying for a geology degree at Canterbury University but after his first year, he took a year off to work in the mine's technical services department. He resumed his studies for another semester but he returned to Pike, becoming a driller for Valley Longwall. He was only 21 when he was killed.

"I was trying to put them on a career path to set my kids up. Ben was loving his job," Rockhouse said.

After the blast, he learned of the mine's failings.

"I have huge regrets about getting my boys involved. You never leave people behind, especially when you have the technology and ability to get them out."

- © Fairfax NZ News