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Another piece of Waihi gold mining history is preserved for posterity. Story and pictures by KIT WILSON.
Not just any 180 tonnes of concrete. This concrete is over 100 years old and shaped like a gold refinery building, and it was winched just over 100 metres to its new home by two tow trucks anchored to the dozer and excavators. The Grand Junction Refinery building was built over 100 years ago to refine the gold and silver produced by the Grand Junction mine in Waihi. Today it is the most visible reminder of a once great gold mine. This concrete and corrugated iron building with its distinctive louvered ventilation system is inside the boundaries of the present Martha Mine, and so is not open to the general public. A spokesperson for Waihi Heritage Vision says the group has been working with Newmont Waihi Gold and Historic Places Trust to find a way of preserving the building and to make it more accessible to the public. “The building could not be accessed while the mine continued to operate, but even when the mine finally closes public access would have been difficult.
Newmont Waihi Gold promoted the idea to move the building for the long-term benefits of the community while it had the resources available in the area. The company also subsequently funded and managed the project. As with the Cornish Pumphouse move back in 2006, Dunning Thornton were engaged to provide the engineering methodology and design, Engineering and Geology the geotechnical and civil earthworks design, and Mount Maunganui Engineering the steel and structural work. Conslab did the concrete cutting and new foundation work and McPherson Contractors from Matamata did the extensive runway earthworks. Just like the pumphouse, the 180 tonne building was cut off its original foundations. But unlike the pumphouse (much heavier at 1840 tonnes), the refinery building was supported internally on a steel frame that was suspended on two large steel tetrapods constructed inside the building. In turn these tetrapods sat on large steel skids that provided the pulling points and slid on steel runner plates.
Waihi Gold’s project manager Kevin Storer says the hardest part was getting the building off the concrete floor that the skids were sitting on, but once the building was on the greased steel runners, progress was smooth, and the building was on its new site in two days. You can now see the Grand Junction Refinery building in its new home by taking a walk around the Pit Rim Walkway in Waihi.
Contractor Vol.34 No.6 July 2010 |
Two heavy haulage tow trucks, two excavators, a Cat D10 and miscellaneous other equipment … enough gear here to start your own contracting business. That’s what it took to move 180 tonnes of concrete at Martha Mine in Waihi recently.
“The solution was to move the building about a hundred metres north, right next to the Pit Rim Walkway. An important part of the heritage fabric of Waihi will once again be available to locals and visitors alike.”
This system isolated the building from any differential stress during the move along the 1:25 inclined causeway and allowed the building to be winched at an angle relative to the two tow trucks.