12' tunnel cost

[cvg]

I'm looking for an order of magnitude cost estimate for a 12 foot diameter drainage tunnel. It would be about 5,000 feet long and probably only 20 - 30 feet below the ground surface. The ground is assumed to be a mixture of sand, gravel, cobbles and silt with no bedrock. Groundwater is not likely to be encountered.

 

[rchanke]

Costs are highly variable from region to region. Best to get a budget cost from a local tunnel contractor. He will certainly need more information than what is given above. Info such as, is lost ground a concern ie. what is overlying the tunnel, are the breakin and breakout through embankments or from vertical shafts, etc.