That sounded like a complaint about digging being too fast for qualified miners, at least on the face of it. That can be slowed down by not giving them any mining experience before embarking, though I can see how that may not satisfy you.
Digging being too fast in general, because only semi-qualified miners (and not many) have to make an entire underground fortress before you're eaten by wolves. By the time they get qualified, they can just fly through stone. And just lowering the speed would only serve to get you eaten by the aforementioned wolves.
I'd figure that perhaps digging was never meant to be a challenge for dwarves. Coupled with the time scale of this game, I don't see the wisdom in making it slower or otherwise more difficult. There's a slight exception to the above: as far as I know (I haven't played anything earlier than .28), in the 2D versions there used to be the risk of cave-ins unless you placed supports in your larger rooms or corridors. I'd like to see this feature make a comeback some day, but hopefully only after this game has been somewhat optimized. The last thing DF needs right now is to become even more resource-intensive.
Maxed-out miners can clear a space (which I think is a thousand cubic feet) of any stone in under a second of real time, which can't be more than a few minutes of game time. Being able to make these sorts of things
at all is well beyond superhuman, but moving that mass of stone (let alone breaking it in the first place)... that requires actual, you know, superman level strength.
I guess an alternate solution would be (and I may have heard this mentioned before), that digging would be a two-part process. First break the stone, then get someone to haul the... apparently, almost
ten tons of stone somewhere else. Might take a few trips.
There could also be a step where it's sifted for gems or ore.
Have you experimented with the parameters, at least? There are some options that, on the face of it, look like they could sort of do what you want.
I have, and there's not.