In dry or near dry conditions, when an auger is used in conjunction with the MTBM
for spoils removal, the method is more expensive than a simple belt conveyor to muck car system.
Neagoy and Akkerman President Maynard Akkerman met with Michels' Pat and Kevin Michels and Bill Weltin to discuss MTBM requirements for the project.
Now the MTBM had become a new design and was still evolving.
Ordinarily, Neagoy says, a MTBM is a two-section machine Because an exit shaft would have to be constructed in the lake bottom, at depth, the plan called for as small a hole as possible.
Instead of two sections of machine measuring approximately 25 feet in total length, Neagoy continues, "there would now be only one shorter section MTBM in order to fit it into the small reception shaft and be able to pull it out of that 20-foot exit hole.
Another issue, primarily relating to concerns about the geology and behavior of the anticipated ground conditions, was that the MTBM should have an independent form of advancement control at the heading.
A decision was made, to put a 'jacking can' (basically a sealed intermediate jacking station), in line directly behind the MTBM, on the front end of the tunnel.