I think the real question should be: Why don't more people dig personal tunnels? It's pretty obvious that digging is an intrinsically satisfying activity. Kids are naturally drawn to digging and we see unmotivated digging behaviour in the animal s all the time.
Most of us lose the digging instinct as we graduate into adulthood the same way we lose the drawing instinct or the the sculpting instinct. But, as adults, we do plenty of menial, repetitive tasks as hobbies. Knitting, chopping wood, doodling, spinning pens etc.
I think just not enough people have been exposed to the joys of digging as an adult and thus, have not been converted to digging as a hobby. I'm sure, if it reached some kind of critical tipping point, personal digging would become a mainstream hobby in the same way knitting & crochet did for young women in the 00s.
I stopped enjoying physically moving large amounts of dirt in my late teens, after years of being free labor for my parents' landscaping efforts.
I still enjoy tunneling underground, making neat passageways, modifying the world, and finding things. It's my greatest pleasure to play on my Minecraft server. This is where I do my digging, tunneling, and many other things.
Your comment makes me think of the tens of thousands of people who pay thousands of dollars to spend a week every year working as amateur porters, builders, truckers, riggers, cooks, mechanics, and cleaners, sweating away in extremely hot, dry, dusty desert conditions. I refer of course to Burning Man.
I don't like digging or being put into a tunnel, I like the free space and the wind, sorry, no digging for me. So a reason why more people don't dig is that some people just don't like it. At least me?
Fascinating stuff, I've always been interested in tunnels and tunnel boring machines. As a teen I built an underground fortress of solitude in the unimproved desert near my house using cinder blocks for support that folks had dumped in the desert after finishing a block wall job. There was mortar mix as well so nearly two thirds of the interior walls were both brick and mortar. It was great fun to go into it during a hot day and cool off. It quickly became rather over run with snakes and scorpions who also appreciated its cool interior[1].
But my strongest memories of the place are about how good it felt to be carving a "space" out of nothing but dirt. It was almost magical in its ability to feel like creating something from nothing, even though it was just digging. Had the dot com crash not happened it was on my schedule to build a basement for my house. I got to see a two story basement (two levels down) in Palo Alto and it was really amazing to me. Almost like having an additional house to do with what you want.
[1] Always made the first visit after an extended absence pretty interesting.
If anyone is interested in the "mole man" from London that the article references:
Since the early 1960s, the man who owns and lives inside the £1m Victorian property has been digging. No one knows how far the the network of burrows underneath 75-year-old William Lyttle's house stretch. But according to the council, which used ultrasound scanners to ascertain the extent of the problem, almost half a century of nibbling dirt with a shovel and homemade pulley has hollowed out a web of tunnels and caverns, some 8m (26ft) deep, spreading up to 20m in every direction from his house. Their surveyors estimate that the resident known locally as the Mole Man has scooped 100 cubic metres of earth from beneath the roads and houses that surround his 20-room property.
In 2008 the high court ordered Lyttle to pay almost £300,000 to Hackney council to pay for repairs, but he died in 2009, leaving the council with a £400,000 repair bill.
Following his death, the property become even more dilapidated – to the point where the council had to fill in the tunnels with concrete to prevent subsidence. When they did so they found Lyttle had stashed four wrecked Renault cars, a boat, several baths and fridges and numerous TV sets under his home. They are still there, encased in the concrete used to shore up the property.
The site was sold with planning permission for the derelict structure
The first person who came to mind when I read the headline was Seymour Cray, who made the fastest computers in the world for quite a while. He used to dig while puzzling over circuit designs.
John Rollwagen, a colleague for many years, tells the story of a French scientist who visited Cray's home in Chippewa Falls. Asked what were the secrets of his success, Cray said "Well, we have elves here, and they help me". Cray subsequently showed his visitor a tunnel he had built under his house, explaining that when he reached an impasse in his computer design, he would retire to the tunnel to dig. "While I'm digging in the tunnel, the elves will often come to me with solutions to my problem", he said. [1]
It's worth saying that this is dangerous; people do die when these tunnels collapse. If you're thinking of digging, be careful; make sure you know what you're doing.
Also make sure you call or visit the diggers hotline before you start to make sure you don't hit any buried cables. Not sure about outside the U.S. folks.
When I was a kid, the kid down the street and I started digging a hole in his backyard. We wanted it to become a tunnel network.
The hole got deep enough for both of us to fit inside, but somehow it became much more difficult to continue digging at that point. Maybe, as the article suggests, we hit a rock, or maybe it was the exertion of lifting shovels full of dirt above our heads.
I can't even dig 6 inches without hitting the rocky mess which makes the foundation of my little down. It used to be a river bed, which makes for great gravel pits and terrible gardens. Nothing will destroy a lawn faster than a utility company coming along and burying a cable. All of your nice topsoil banished beneath a rocky substrate.
"Excavation cave-ins cause serious and often fatal injuries to workers in the United States. An analysis by the National Institute for Occupational Safety and Health (NIOSH) of workers' compensation claims for 1976 to 1981 in the Supplementary Data System of the Bureau of Labor Statistics suggests that excavation cave-ins caused about 1,000 work-related injuries each year. Of these, about 140 result in permanent disability and 75 in death. Thus, this type of incident is a major cause of deaths associated with work in excavations and accounts for nearly 1% of all annual work-related deaths in the nation."
Yep, as an eight year old I dug a hole in the side of a fairly solid sand dune. Just before I went in for about the tenth time, the roof collapsed and I escaped with my life.
Most of us lose the digging instinct as we graduate into adulthood the same way we lose the drawing instinct or the the sculpting instinct. But, as adults, we do plenty of menial, repetitive tasks as hobbies. Knitting, chopping wood, doodling, spinning pens etc.
I think just not enough people have been exposed to the joys of digging as an adult and thus, have not been converted to digging as a hobby. I'm sure, if it reached some kind of critical tipping point, personal digging would become a mainstream hobby in the same way knitting & crochet did for young women in the 00s.