I parked near an interesting construction site today. There was some large device that I suspect might have been a pump or generator (sounded more pump like) and there was a large crane rigged up to drill some very deep looking holes. I recorded a fair bit of material even though most of it was pretty regular cyclic mechanical sounds. I am glad I did because at one stage the drill must have hit some hard rock or some other snag as the entire array shook quite violently. The sound for this was not quite as spectacular as the entire 100 meter high rig shaking, but it was still a good sound to grab.