There seems to be considerable ahh... disagreement about the proper way of digging. =)
Complete strip mining

All your mineral are belong to us.
The effort is minimal. A single dig order for an entire level - assuming your military can handle anything that moves here. =)
Of course you need a lot of storage capacity if you don't want to waste anything but what's the point of not building storage items... from free wood?
Alas, stone-based storage only offers about 50% of the storage space of wood chests. This game was written by hippietreehuggers!
Probing shafts and tunnels

To even "light up" the mineral locations, you end up excavating 33-40% of the level without intentionally mining anything.
Much higher likelihood of you having to "fix things" like tunnels hitting a hole in the ground.
With strip mining, the dwarves dig around any obstacle, leaving the problem spots highly visible when they are done.
Of course, you can avoid "mining the wrong things" by carefully navigating a single miner around every resource block. But then you won't be doing anything else because you have to be watching every single dug-out block.
Seems like an awkward way of doing things.
Building a single shaft down
I did the math in another thread (where it was way off topic =) and the chance of finding any resource block at all (even if it's just stone) is about 30%.
With a layer having maybe 6 different types of resources (type depending on depth), your chance of finding the thing you're looking for is 5% per level dug down... or zero when it doesn't exist there.
Stumbling around into random directions like a drunken dwarf isn't the most efficient way to go about mining. I would expect more from a dwarf. (Is there such a thing as a stoned dwarf? Does that mean something entirely different?)
Complete strip mining

All your mineral are belong to us.
The effort is minimal. A single dig order for an entire level - assuming your military can handle anything that moves here. =)
Of course you need a lot of storage capacity if you don't want to waste anything but what's the point of not building storage items... from free wood?
Alas, stone-based storage only offers about 50% of the storage space of wood chests. This game was written by hippietreehuggers!
Probing shafts and tunnels

To even "light up" the mineral locations, you end up excavating 33-40% of the level without intentionally mining anything.
Much higher likelihood of you having to "fix things" like tunnels hitting a hole in the ground.
With strip mining, the dwarves dig around any obstacle, leaving the problem spots highly visible when they are done.
Of course, you can avoid "mining the wrong things" by carefully navigating a single miner around every resource block. But then you won't be doing anything else because you have to be watching every single dug-out block.
Seems like an awkward way of doing things.
Building a single shaft down
I did the math in another thread (where it was way off topic =) and the chance of finding any resource block at all (even if it's just stone) is about 30%.
With a layer having maybe 6 different types of resources (type depending on depth), your chance of finding the thing you're looking for is 5% per level dug down... or zero when it doesn't exist there.
Stumbling around into random directions like a drunken dwarf isn't the most efficient way to go about mining. I would expect more from a dwarf. (Is there such a thing as a stoned dwarf? Does that mean something entirely different?)