At the time of our visit I didn't know the story of the pumphouse or why it needed all this steelwork.
Explanation: In 2006 it was moved here (in one piece!) from where it was in danger of collapsing into the open cut.
See: https://www.waihigold.co.nz/about-2/history/the-cornish-pumphouse/moving-the-cornish-pumphouse-august-7-to-november-8-2006/