DonnerVarg

That's exactly how I do it in many cases, except I like to have an auto-shutoff for quarries when they pick up something that could indicate a dungeon, abandoned mineshaft, stronghold, or player tunnel. That requires logic, though I could have a manual shutoff that's just a lever on the link, I prefer to have the lever on a redstone lamp so I can see at-a-glance if it's running.

Energy Link will stop powering Buildcraft stuff if you supply it with a redstone signal. (n.b.: Both the Quarry and the Energy Link have internal energy buffers. The Quarry will keep going for a bit after you disable the energy link with redstone signal, the Energy Link will keep the Quarry going even longer if you simply remove it's IndustrialCraft power supply.) The Link draws 22 EU/tic if it's adjacent to a quarry, but if you use pipes (including power teleport pipes) it'll draw 72 EU/tic no matter how many quarries draw on it. (I've tried up to 8.) So you're better off with a link adjacent to your quarry if you're running 3 or fewer at once. You're better off piping your power if you're using 4 or more quarries at once.