I came to understand how much power is in oil through digging a big hole. I had to do some excavation for a mountain cabin I am building. After digging by hand

I came to understand how much power is in oil through digging a big hole. I had to do some excavation for a mountain cabin I am building. After digging by hand for a while, we bought a 1-ton micro-excavator. One bucket from the excavator is equivalent to about 10 shovels. The avg time per scoop is similar, and it burns half a tank per day, so it works out such that it does the work of about 10 men on around 10 l/day of diesel. Thus I discovered that 1 liter of diesel can do about 1 man-days worth of dirt moving. This liter costs about $1 right now. A day laborer would cost around $160-$250. After digging hard ground by hand where you have to fight for each shovel full, seeing the tiny excavator rip 100lbs of earth like a toddler playing in the sandbox makes you appreciate what a gift oil is. Bigger excavators with better operators are more efficient. I would not be surprised if a big one approaches the 9man-days / liter theoretical limit you calculated above.