The historic 1931 Golden Point stamper battery at Macraes is recognised as Otago's best-preserved stamper battery and was operational into the 1950s.
The engine, which was used to help in extracting gold and scheelite for military use during both world wars, was removed from its housing shed for restoration work in October 2011.
The Golden Point gold mine is now a heritage site and sits on Crown land. Restoration of the engine was funded by the Department of Conservation (Doc) and Oceana Gold.
However, Doc North Otago ranger Kevin Pearce said the restoration work had taken longer than expected, because many of the replacement parts for the diesel-powered Tangye engine had to be made by hand in Oamaru.
''We were hoping to restore it in a couple of months and have it in before Christmas [2011], but because it's such an old engine it took a bit longer.
''But we finally got it restored and we have run it at the workshop, and we have it back in there now and we hope to give it a test run next week, or the following week.''
He said an open day would be held in December to allow the public to view the working machine in operation.
