If you want to lock up your computer, try this:
Note the size of the mining zone and the LUA use.
In contrast, if you break the mining zone into subzones, it’s much faster and more efficient:
Operating System
Windows 10 Pro 64-bit
CPU
Intel Core i7 6700K @ 4.00GHz 49 °C
Skylake 14nm Technology
RAM
16.0GB Single-Channel Unknown @ 1066MHz (15-15-15-36)
Motherboard
ASRock Z170 Extreme3 (CPUSocket) 33 °C
Graphics
DELL 2405FPW (1920x1200@59Hz)
2047MB NVIDIA GeForce GTX 660 Ti (EVGA) 78 °C
It is Mother Earth’s, (or whatever planet this takes place on) vengeance on you for your desecration. 
But seriously I think that make sense for the smaller areas to take less time as you are dealing with smaller surface areas. Much like the same amount of powdered medicine dissolving faster that a solid pill form of it.
oh yeah it makes sense but it’s something that at some point they should probably optimize a bit. The lag really is extreme – like hours of real time to do a single game day’s worth of mining even when set to high speed.
its quite anoying when you have to micro manage digging
I can confirm this to be an issue for me in Alpha 17 R593 as of today. I couldn’t figure out why my game went choppy and awful until I saw this thread. Instant fix.
im having this same issue but i dont think mining is the only thing, im not mining whatsoever and im getting insane lag wtih the same issue with the lua so it might be if you do anything in bulk idk, the only thing going on in my town atm is building walls around the town so thats the only thing i can think of, eitherway this should get patched sooner rather than later >.> its real annoying and it only started in alpha 17
