This historic place was registered under the Historic Places Act 1980. This report includes the text from the original Building Classification Committee report considered by the NZHPT Board at the time of registration. The principal mines at Thames were all near the beach at Grahamstown and the workings extended far below sea-level. Consequently, dewatering of the mine was a major problem requiring constant pumping. A Big Pump installed in the Imperial Crown Mine in 1871 was able to dewater a number of mines. Due to reducing gold returns and the cost of financing the pumping, the operation was closed down in 1879, but was refinanced and restarted in 1880. In 1885 the combined capacity of the Big Pump and a smaller pump in the Queen of Beauty mine proved inadequate to cope with the flow of water. The Queen of Beauty pump failed in a spectacular accident. Gold production over a large area was severely curtailed. In 1895 the Thames-Hauraki Goldfields Company acquired the Queen of Beauty Mine. With the assistance of a government subsidy it enlarged the mine shaft and installed the new Big Pump. The quadrants surviving at the mine site were part of this massive machine. This pump continued to dewater the Grahamstown area of the Thames goldfield until 1913, when the workings at the 305 metre (1000 foot) level broke into a fault and water, too great for the pump to handle, flooded the workings. The whole of this part of the Thames goldfield then closed down.