Mrs Osborne, 50, lost her husband, Milton - the father of their two children - in the 2010 mining tragedy on the West Coast.
The explosion "which killed 29 miners and contractors " happened just a month after doctors told Mrs Osborne she was again battling Hodgkin's lymphoma. She had been first diagnosed with the blood cancer eight years earlier but overcame it with radiation therapy.
Now, more than 5 years after the tragedy that left her a widow, Mrs Osborne has revealed she has been fighting cancer the whole time since.
In an exclusive interview with the Weekend Herald, Mrs Osborne said she wanted an alternative to conventional painkillers that mask the side effects of her treatment.
She is set to self-medicate with cannabis oil and is prepared to be sent to jail for doing so.
Mrs Osborne said chemotherapy had left her feeling like dying and she would rather have had her own life taken by the illness than her husband's in the mine.
With pressure increasing on the Government to change its stance on medicinal cannabis, Mrs Osborne has added her name to a list of high-profile Kiwis - including the late Sir Paul Holmes, the late Martin Crowe and a former president of the Council of Trade Unions, terminal cancer sufferer Helen Kelly - embracing medical marijuana. Like Ms Kelly, she wants New Zealand to decriminalise it.
"I'm going to have to do it illegally to see how I go. If that makes me a criminal, so be it. I'm prepared to go to jail if it eases my pain," Mrs Osborne told the Weekend Herald.
"I have never touched drugs in my life, I've never even touched a joint. But there has to be something more than this. Going through chemo is just unbearable at times. Through all of Pike River, no one knew about this. I've kept it very close. But the time has come. We as a nation have to talk about this; we have to have a sensible debate at the very least."
Mrs Osborne said she had thoroughly researched the pros and cons of cannabis oil, with the legal risks an obvious concern, and her mind was made up.
"I'm going to go ahead with it. I know it's illegal but I'm on so much medication, I rattle when I walk.
"All these synthetic, horrible drugs that go into me to mask side effect upon side effect from chemo twice a week for six months, it is absolutely horrible. You just want to curl up. It makes you feel like dying.
"What I've read about cannabis oil has been positive and if I could get rid of all these drugs and replace it with one natural herb that's grown in the ground, I'd be all for it.
"I've had five good years where it wasn't acting aggressively and hadn't spread to any other lymph nodes so the medical advice was to watch, wait and not treat until absolutely necessary. It's now at the stage where tumours have grown quite considerably and are strangling main blood vessels in my legs.
"I couldn't do radiation treatment again because I'd had the maximum dosage in the area before it would start weakening bone. Chemo was the only option."
But now Mrs Osborne wants people in her position to have the same entitlement to medical marijuana as sufferers in nations like the United States, Canada and Australia. She knows that in this country, she will need to turn to the black market.
"There's no shortage of offers. I've had so many people come forward and say they want to help get me cannabis. It's been overwhelming.
"My community has given me so much help and support. I have to thank my daughter, who sits with me through every chemo treatment, my son and all my close friends, especially Helen Kelly; she is my inspiration."
Mrs Osborne said she had not been able to work for six months and refuses to go on the sickness benefit on principle. She said while medical experts were positive about her outlook, "they can almost guarantee it will come back again in around 5-7 years".
The Weekend Herald requested an interview with Associate Health Minister Peter Dunne to discuss Mrs Osborne's case and New Zealand's stance on medical marijuana. A spokesman refused.
The Ministry of Health refused to comment on Mrs Osborne's case, but said it had received 68 applications for medicinal cannabis since January 1, 2015.
"The Ministry of Health works with clinicians to facilitate access to medicines which have been proven to be effective and safe," said Chris James, the acting group manager of regulatory body Medsafe.
Mrs Osborne has not applied for a ministry exemption, saying that if her high-profile friend Ms Kelly cannot be approved for her terminal ilness, "then what chance have I got?"
Mrs Osborne vowed her health would not stop her ongoing fight over the Pike River 29.
"I want justice for our men, I want someone to be held accountable and I want someone to at least try to bring my husband home."
Govt eyeing drug aid
The push to legalise medical marijuana continues to build, as the Government this week weighed up whether to soften rules on minor drug offences.
Following a major international study saying the punitive approach to drug offending hasn't worked, Associate Health Minister Peter Dunne reiterated the Government's commitment to review drug policy and make sure drug offending is primarily seen as a health matter.
Mr Dunne said his comments were unrelated to an increasing number of high-profile Kiwis admitting to self-medicating with cannabis.
Police Association president Greg O'Connor said any relaxing of the rules must target suppliers. He suggested a regulated approach, such as in Colorado, could be more appropriate than in nations such as Holland where dealers were not tackled.
The Government does not support the use of unprocessed or partially processed cannabis leaf or flower preparations for medicinal use. However, applications can be made through the Ministry of Health for medicinal cannabis products that may be considered for ministerial approval.
In June last year Mr Dunne approved a landmark case, the one-off use of medicinal cannabis for terminally ill 19-year-old Alex Renton who died on July 1.
- by Simon Plumb of the Herald on Sunday
