Since power lines are cheaper than conveyors (and have to be run anyway to power the miner), I elected to build all the infrastructure over by the coal and ship power back instead of shipping coal in.
Always a good idea. You are likely to end up with a dozen or so generators and they take up a fair bit of space. Eventually you'll get hypertubes to travel between your sites and they won't feel that far apart.
Are they faster than mk3 conveyors? I used to just use conveyors to get places.
For character traveling, a LOT faster, plus with some foundations on the wall of a cliff you can end up going vertically, rather than having to figure out the right angle for incline/etc.