Slow digging costs the same and bills half the feet
The machine, the crew, and the daily burn don't change when production halves, and the estimate only knows dollars per linear foot.
On a surface job a bad day costs labor hours and you send people home early. Underground, the machine, the shaft, the shoring, and the mandated safety manning bill the same whether the crew makes sixty feet or twenty, and you can't send the rescue team home to save a day. A per foot estimate has nowhere to carry a fixed daily cost, which is where the money leaves.
The size of it
A machine and crew that pencil at $250 per linear foot in clean digging still burn $18K to $25K a day in cobbles while producing a third of the feet. That distance between day cost and billed feet is the single biggest reason tunnel bids look profitable and tunnel jobs don't.
Machine ownership and shaft shoring rental accrue by the calendar day. The revenue item is a linear foot of completed bore. Soil that halves production doubles your day cost per foot with no additional billable feet, and 29 CFR 1926.800 then staffs the job with people who bore nothing: a competent person running air monitoring when the crew goes underground and again partway through the day, check-in and check-out, daily hoisting inspection, and a five person rescue team on site or within 30 minutes travel for crews under 25 underground. A potentially gassy or gassy classification at 10 percent LEL limits you to MSHA approved diesel equipment and shuts down everything but gas control.
Three moves, in order
Step 02: Equipment cost basis
A true internal rate per machine covering ownership, maintenance, fuel, and transport, charged to the projects that used it.
What else costs tunnel contractors money
The same mechanism in other trades
What tunnel owners ask
Why tunnel bids look profitable but jobs lose money in bad ground?
The machine, the crew, and the daily burn don't change when production halves, and the estimate only knows dollars per linear foot.
What does it cost?
A machine and crew that pencil at $250 per linear foot in clean digging still burn $18K to $25K a day in cobbles while producing a third of the feet. That distance between day cost and billed feet is the single biggest reason tunnel bids look profitable and tunnel jobs don't.
What do I do first?
Build a true day rate for each drive: machine ownership, shaft and shoring rental, crew, and the 1926.800 manning that produces no footage.
What are tunnel contractors supposed to be making?
Tunnel runs 23% gross margin, 16% overhead and 7% net profit before taxes at $1M–$5M. The all-trade average is 7%, so this trade sits right on it. The CFOS target is 10%.
Which part of the system fixes it?
The step is number 02, equipment cost basis. A true internal rate per machine covering ownership, maintenance, fuel, and transport, charged to the projects that used it. It comes from chapter 2 of CONTROL: The Construction Financial Operating System.
Josh Luebker ran commercial construction projects before he ran the numbers behind them, on data centres, military bases, hospitals, and high-rises. He wrote CONTROL: The Construction Financial Operating System, which is an eight-step framework for commercial subcontractors, and it publishes on October 1, 2026. He is a master electrician who moved into the office and kept the field vocabulary.
Sulphur Prairie Operations LLC maintains the benchmark reference behind these figures. Every edition is reconciled against the newest CFMA survey release before it publishes here. Where a figure changes between editions, the older edition keeps its year in the title so a citation to it stays correct.