It sounds like they didn't intend to drill into magma, but is it possible to survey the land and intentionally find magma near the surface to exploit in this manner? If not, isn't the question of whether you can effectively harness the energy or not moot?
Not going to say its easy. But you can pretty accurately map magma under the surface using seismology. I believe it requires an earthquake and having the correct equipment in place, so its far from ideal. But it does work well.
It's been awhile since I've sat in on geology, but I seem to recall that they can use short-range seismic signals (by firing a shotgun shell into the ground). I'm not sure as to the resolution -- one could imagine getting better resolution firing multiple shells simultaneously over a certain area. My $.02