It's been six years since the Pike River mining disaster, six years since 29 men lost their lives, their bodies never recovered.

The government, at the moment, is trying to seal the mine. The methane levels, and the rock slide that was triggered by the explosions mean the mine can never be accessed again.

Some of the families of those men oppose sealing the drift. They oppose sealing the tunnel. It's almost 2.5km long and it leads you to the coal seam. That's where the rock slide is, where the rock has collapsed and it sits about 20 metres deep. In other words, it’s impenetrable. The bodies of the men are believed to be on the other side of that rock slide.

Some of the families believe it’s possible that some of the men could be on this side of the rock slide. They say not all of the drift has been searched and they’re right. It hasn’t. It depends who you talk to, but some experts I’ve spoken to say you could wear gas masks and walk up that drift. There have been no explosions for years, so you could search the drift, they say.

The families say it could give some of them a chance to bury their men, and it could also provide further clues and evidence about what happened that day, what went wrong inside that mine.

On the other side of the debate, the government and Worksafe will tell you the risk to human life is too great.

The issue is how you measure risk. No government minister wants to send a human into that environment, because what if they’re killed? The families say they'll go in. They'll walk the drift.

Nick Smith said they’ve already built a seal, 30 metres into that drift. It needs another week’s work to complete, and then they’ll be placing a 30 metre thick seal at the portal, the entrance of the mine. That’s it. Closed forever. Whatever is inside that mine will remain buried deep inside it forever.

In the last 24 hours, one of the contracting companies - Allied Concrete - has pulled out. It says it won't supply the products to seal the mine, and doesn't want to further traumatise the families of those who died.

So what now? Many on the Coast will tell you the drift is safe. You could re-enter, with the right equipment, and go to the rock slide. You could determine, once and for all, if you can recover some of the bodies.

So what do you do? Do you have some sympathy for the families of those who died? Do you understand what they want to do, and why? Or do you bring in security and push the protesting families to one side, and seal that mine? It's the toughest of calls.