The visit was carefully timed to catch the setting of the Wirth drill on top of one of the 10-ft diameter drilled (or soon-to-be-drilled) shafts.
You might remember from previous entries that the first step in drilling each shaft is to install a tubular steel guide. The guide has teeth on the bottom, and is set a couple of inches into bedrock. The Wirth drill (http://mhwirth.com/our-products/pile-top-rigs/) is a pile-top drill that mounts on top of guide, and drills another 30 feet or so into the rock.
Today, the drill was set on a new shaft on the Portsmouth side, where it will drill away for a few days before being moved again. The photos below show the bit being hoisted into place.
The first two photos below show one of the form sections being leveled and hoisted into place.
The final photo is the stockpile of completed segments. These must be carefully protected, as each is cast to mate with the one above and below it. Also shown is one of the rebar cages for the drilled shafts.