It took one of the country's worst mining disasters for broken-hearted mums Anna Osborne and Sonya Rockhouse to forge a friendship so close, they consider themselves sisters.
What started seven years ago as a fight for justice for the 29 men who lost their lives in the Pike River Mine explosion has blossomed into an unbreakable union between two bereaved women, who have shared the worst life has thrown at them – losing family members and bravely battling a deadly cancer.
In a harrowing journey that still continues, the teacher aides tell Woman's Day they are blessed to have found a special kinship as they rail against the injustice of losing a husband and son in the tragedy.
Sonya says it's proved a silver lining in the bleakest period of her life, with the pair "clicking" from the outset.
"We 'got' each other," says Sonya, whose 21-year-old son Ben was killed in the 2010 blast. "People grew sick of hearing about Pike – my own family included – but we had to live it and we couldn't be over it.
"When I would visit Anna, I'd know that she would understand how each of us was feeling. She said it was good for her to be able to feel relaxed, and she could talk to me about it and I could talk to her."
So when Anna, who lost her husband Milton, was faced with a cancer operation and chemotherapy in 2016, Sonya didn't think twice about opening her Christchurch home to her new pal.
"I was devastated because we'd established a friendship really quickly and we kept each other buoyed. When she got her cancer, I thought, 'Right, I'm not letting cancer take her away from me now!'" recalls Sonya, who introduced Anna to the late trade union leader Helen Kelly for advice on medical marijuana to help ease pain during treatment.
Having come through that cancer scare, Anna went into remission, only to face a second dire diagnosis earlier this year, with tests showing her terminal Hodgkin's lymphoma had spread from her groin to her spleen, liver, breast bone, neck and under her arm.
The timing couldn't have been worse with Anna having welcomed her first grandchild, born three months prematurely in December, followed by a shock invitation from the Pike River Recovery Agency to go inside the mine.
For years, families had been forced to stop at the mine's locked gates northeast of Greymouth and only granted entry on special occasions. Now the unthinkable was happening.
Tells a stunned Anna, "Here we were fighting for seven years to get up to the security gate and now the agency invites us to go up to the 30-metre seal as far as we can into the drift!"
In April, the pair travelled to the mine, where they met Pike River Re-entry Minister Andrew Little and followed the same passage their loved ones walked that fateful day.
Decked in safety gear, the two women held each other as they entered the chilly, cavernous chamber.
"After feeling all the weight and my health not being great, Sonya really did need to support me," explains Anna. "We were taking the very path into the drift where my husband and her son walked that day, the 19th of November, but they never came back out."
As the pair navigated the rocky, blast-scarred terrain underfoot, their thoughts centred on the final hours of their loved one's lives.
"We were both crying," recalls Anna. "Our emotions really took over. Going 30 metres in and looking up around the tunnel, seeing water dripping from the roof, the roadway rocky and uneven, and how damp, dark and cold it was, I thought what an absolute hellhole that place was.
"Then we were quiet. We were just reflecting on what it was like for our men to walk down there, and what it was like that day for them up until the explosion and knowing they weren't aware of it."
In silence, the pair reached the concrete wall before breaking down at the blockade that separated them from family trapped behind it.
Tears streaming down her face, Anna recounts, "If there was a door handle that I could have turned and opened, I would have run up there and kept on going because that's where my husband is. I held the wall of the drift and I made my promise to Milton that I'd do all I could to bring him out. I told him 'I love you – I haven't forgotten you' and that I would be back."
Sonya – whose second son Daniel was one of two men to survive the deadly blast – says she couldn't help think of the anguish her boy felt as he struggled to carry a miner to safety in the aftermath of the powerful blast.
"He walked out the same portal," she tells. "All the way out, he thought they were going to die. When he got to the end, there was nobody there. He just collapsed on the ground and cried. I knew where that had happened and I knew the system that he had rung through on to say that they were alive. I'm looking at all that stuff thinking the last time that was touched, that was Daniel."
Their relentless quest for justice led them to spearhead the Family Representative Group, but it's the women's companionship and sister-like bond that is the backbone to their friendship.
"I love her heaps," says Sonya. "We couldn't have got to where we are without each other."
Explains Anna, "If I'm having a down day and a real emotional time, Sonya knows what it's like. I cry freely and we talk about it."
Visibly fatigued from her latest round of auto-immune treatment, it's been a rollercoaster year for the gutsy West Coaster. Her granddaughter Amalia's early arrival was an added stress, especially when the tot suffered major health problems in her first weeks.
But seven months on, the family is rejoicing in her survival and it's given Anna a renewed determination to get through the latest cancer battle.
"She's a little miracle," says the doting grandmother.
"She's the apple of my eye and makes me smile. She gives me a whole different purpose in life. I've been fighting for Milton who's dead and now I'm also fighting to stay alive for my grandbaby."
The women take heart from the fresh plans to re-enter the mine by the end of the year. Anna says it's something she owes her husband and their children, Alisha and Robin, who struggle to go near the mine.
"It's nearly eight years on, but it's still as fresh and raw as hearing it for the first time," tells Anna, who was playing pool with Robin in a pub waiting for Milton to celebrate their son's first pay cheque when she was told the devastating news. "We have no bodies to bury. My husband is trapped in a place where I don't want him to be."
With no cure for her cancer, it has become important to Anna to see the quest through for as long as possible.
"I know eventually one day it will take me. But at this stage, I've still got a lot of life left. My grand-daughter and Pike keep me going. It's unfinished business with Pike, plus I want to grow old with my granddaughter."
Adds Sonya, "It's been an incredible journey and I'm very blessed to have met Anna. We'll be friends forever. That's one positive that has come out of all of this."