Humans have been tunneling for - take your pick - either thousands, many thousands, or, after a fashion, possibly tens of thousands of years. How much better at it have we become?
Technology, population and knowledge have been increasing exponentially for tens of thousands of years. Many areas of human endeavor have quite recently been improved dramatically, especially with the advent of computers. This is why first principles analysis is necessary.
A supremely key point Mr Musk was making in the early days of the Boring Company (TBC) was that the hypabyssaly low rate of boring was the #1 target. UNLESS a boring machine can achieve a Speed Made Good of several times the velocity of a snail - as opposed to several times less, in pre-TBC days - then the entire concept earns a Fail.
The #1 target is solving traffic and other problems with our road network and overall legacy transportation architecture. Faster tunneling is a means to that end, but not the goal
per se. What matters most is end-to-end metrics such as total cost per unit of capacity, average transport speed, local and global environmental impact, etc. If BC could hypothetically find a way to win on these metrics without fully hitting their tunnelling speed goals, I doubt anyone would deem it a failure except those who will go to any length to find something to criticize about Elon Musk. Also, merely achieving snail velocity would be a major 10x accomplishment and would revolutionize the industry.
So.....that's the basics. And I do not yet see on your spreadsheet any grasping of these fundamentals: (1) Distance per unit time and (2) Size of boring head (= size of borehole).
Refer to the Construction sheet. Also, Warren and I discuss construction at length in the video.
(1) Calculations based on TBC's claimed drilling speed targets can be found on cell region B40:E55.
Note: It's hard for me to directly convert this to cost improvement estimates without having access to more information. However, BC claims they have already hit costs under $10 million per mile even with the Hawthorne test tunnel. The LVCC project was sold for $48 million, of which LVCVA CEO Steve Hill says about $40 million was the cost of the big underground station. If BC approximately broke even on this pilot project, that would leave $8 million for the 1.6 miles dug, which is around $5 million per mile.
(2) This is mentioned in the Key Innovations list at cell B16. It is not expounded upon because this is one of the few things Elon has actually taken the time to explain well about BC in public interviews, and because the advantage is somewhat obvious.
Now: are you able to find any such data? Has TBC demonstrated, or hinted, at performance enhancing technology? I do think they have: there appears to have been progress with how to deal with ejecta. That's good but, as from the worlds both of mechanics as well as economics, "NBNS". That is - Necessary But Not Sufficient. A good abbreviation to hold on to.
This is bumping against my limitations as an outside observer. BC has been quiet about how well Prufrock development is going. My understanding is that the first "production" version of Prufrock is currently digging the extension to Resorts World. We will need to wait until that tunnel is complete to get a sense of the delta in speed between the LVCC tunnel, drilled with heavily-modded conventional TBM named Godot+, and Prufrock V1. Much of my current spreadsheet is based on evaluating the performance of the completed system and improvement opportunities available, as well as debunking misinformation.
Nonetheless, according to Will Bradbury from A Boring Revolution (who purports to have extensive engineering experience in the construction industry), even the LVCC tunnel was dug unusually quickly. Based on comparisons of the LVCC Loop and the Hawthorne test tunnel to other projects such as the Seattle Alaskan Way Viaduct tunnel, I tend to agree.
