Here's a closeup of of a drill bit:
They also mix the water with some heavy-duty soap stuff, in order to form a thick foam; apparently this helps to drive the cuttings back up the well casing:
Here's some of the foam flying out of the exhaust pipe (there's probably a better term than "exhaust pipe" for this thing....):
Job site is looking busy:
Sometimes the top of the well casing gets bent inwards from the pressure of the hydraulic hammer; then it has to be cut off so that the fresh casing can be welded on straight. Boyd hit a huge rock boulder almost 25' thick from about 160-185 or so, which involved a ton of pounding to get through; you can just see the slight bent portion in this picture:
Here Boyd and his helper Robert are making the new casing section plumb with the old one (see the little magnetic level? I've got one of these at home, never realized it could be used for drilling a well.... :):
If the new casing is not vertical (checked in both dimensions), they fix it by nudging the hydraulic lift controls which support the drilling rig truck (the rear drive wheels are not even touching the ground). Kinda cool, to see an entire truck shaking this way and that just to bring that 20' high casing section into true...
This clamp mechanism is used to hold the old and new casing sections in-line with each other until they can be tack-welded together:
When preparing the bid, Boyd had told me I could save some money by specifying cheaper well casings that are made in China. He doesn't recommend this though, since the quality is inconsistent and the steel is usually quite soft. This results in occasional broken welds while pounding the case into the ground. One time on another job he mentioned that he actually broke the weld w/o realizing it and pounded the upper section about twelve feet into the lower section - ouch! I am paying the extra money for high quality components...don't want to take risks with your water supply!
It's probably pretty obvious by now, but I find this well drilling stuff pretty darn fascinating. The whole idea of getting a usable supply of water from deep in the ground is cool just to start with; then watching the process of pounding 20', 300+ lb steel casings into the earth is even better. Now let's just hope we hit water before I run out of money.... :-)
Finally, if you're interested I found a lot of good information on wells and groundwater at the American Groundwater Trust site...