Cost of proposed reentry tunnel unknown

THE Pike River Recovery Agency says it cannot yet estimate the cost of a second tunnel suggested as part of the reentry of the mine drift.

The agency has a threeyear budget of $23 million.

Creating a 200mlong tunnel into the drift is one of three reentry scenarios considered by technical experts meeting in Greymouth in the past two days.

The other two options are drilling a mansize borehole; and reentering the main drift as it is, with no second means of egress (exit).

The entirely new tunnel would be 2m by 2m, about 200m long, to the pit bottom in Stone area. The agency said it was too early to say how much that could cost, or exactly where the drive would start.

‘‘A 2m by 2m tunnel, if it can be achieved, would provide ventilation, a second means of egress and quicker access to the areas of interest to assist with finding out what happened and recovering any remains,’’ agency chief executive Dave Gawn said.

‘‘We still have a lot of work to do developing these three options and expect to be able to provide more detail in upcoming weeks.’’

The reentry project is only for the drift, the stone tunnel leading into the mine itself. Only 400m of the 2.4kmlong drift has not been searched. The reentry is not about body recovery, as most are believed to be behind a massive rockfall.

Tunneller McConnell Dowell started work on the drift, 5.5m wide and 4.5m high, in September 2006. By the following May they were 729m in, and it took until December 2008 to reach pit bottom in Stone.

‘‘We need to continue our planning even while the minister is making his decision about whether he’s confident that reentry is possible,’’ Mr Gawn said.

‘‘The Pike River families have been waiting for more than seven years now and it’s important that we keep the pace up, while not sacrificing any finer details around health and safety,’’Mr Gawn said.