April 25th 2010 -
The TBM is at 6,745 meters. There is up to 1 meter over-break. Elevation is 91 meters below the surface. Daily mining average is 12 meters.
The Invert Concrete Carrier is at 4,775 meters.
My heart pours out for these people, and I have developed a great affection. I just came back to blogging, complained that they weren't reporting without me, and here we get a report! I really am their only customer for these things! I'm glad they get tons of money no matter how bad things get.
They have slowed down and are getting 1 m of overbreak. However, they are in the extremely hard and tough dolostone. This is the stuff that resists the flow of Niagara Falls! That 1 m of overbreak must be worse to handle that the 10 m of Queenston Shale overbreak, since it must be coming down in big hunks. The shale might have unraveled as gravel, but I wish I knew.
As I have mentioned before, it is the circular cross-section that has brought this on. The stress concentration is just too high at the roof. Unfortunately, this rock has a tendency to deform 'forever', which means it will put high pressure on the lining.
They don't even mention their 'little problem' with the main lining. This was the main thing I was thinking about when I first wrote about the tunnel (referenced in Geofish Clarified). The lining is on the critical path for the final working tunnel, and it is grievously stuck. They are trying to plaster on endless coats of shotcrete to beef up the overbreak. It's like my horrible problems the past week trying to cover up a garish pink wall in the basement with Atomic Tangerine. I'm up to 5 coats already, and then I had to go back with 2 coats of covering white! Blah!
So, I think they are on track for 4 billion. Since the lining is so delayed, I really expect another temporary lining failure. This will knock it up to 5 billion.
One good thing, this tunnel will break the world record for Highest Price-Earnings Ratio.