Controlled blast planned for 300 George Street?
I've had one of the readers, Simon, send this photo in that shows what looks like preparations for a controlled blast at the excavation site. You can see in the top left corner of the photo a rig drilling holes into the rock. I can't think of any other reason for these holes apart from setting some explosives to clear the rock.
Here's a magnified part of the photo above showing the area being drilled…