Pumphouse on the move
The steam machinery housed inside the pumphouse was used until 1914, when it was replaced by electricity. During the 1930s the machinery was stripped out and the building became derelict.
During 2004, historic underground mine workings threatened the stability of ground beneath the pumphouse and investigations concluded that the only way to protect the building was to relocate it to a safe site.
In 2006 internal bracing was installed to strengthen the structure and earthworks were carried out to construct the relocation causeway. In an acclaimed feat of engineering, this iconic building – weighing 1840 tonnes and standing three storeys high, was moved in its entirety, 300 meters to its present site.
The building was shifted by carefully sliding it along teflon-coated concrete beams.
History and monitoring up to Dec. 2005
- The Cornish Pumphouse was built around 1904 to house steam-driven pumping machinery needed to dewater the mine. The pump was used until 1913 and kept in working order until 1929. After this it was abandoned, the machinery removed, and the steel beams inside removed for scrap.
- In 1961 the collar of No. 5 shaft, west of the pumphouse collapsed, leaving the structure on the edge of a potentially dangerous void.
This aerial photograph taken from the south in the mid 1980s shows the collapsed No.5 shaft on the left (west) of the picture.
- In 1987 Waihi Gold Mining Company fenced the area around No.5 shaft for public safety. Construction of Martha Mine had begun and a viewing platform was placed next to the pumphouse. Paths were constructed and the area planted with native trees and shrubs. With the town’s Information Centre and the Martha Mine Education Centre operating close to the pumphouse the area further developed as a significant tourist attraction.
- By 1995 regular monitoring of the building and surrounding area by Waihi Gold Mining Company showed that the pumphouse was slowly tilting, and that the ground on which it was built was also moving.
- In 1999 access to the pumphouse was restricted following a series of nearby ground subsidences and the increased danger of a similar subsidence of No.5 shaft immediately adjacent to the structure.
- By the beginning of 2005 it was obvious that the pumphouse was tilting dangerously and the ground on which it sat was continuing to move. Experts advised that if it was to be saved the building itself would have to be moved. All interested parties met to consider the future of the structure. In June 2005 conservation architects responsible for moving the Museum Hotel in Wellington got a close look at the condition of the 100 year-old structure.
- In June 2005, a 100 tonne capacity crane was brought on site to secure the weight of a small drill rig above the partially collapsed No.5 shaft. The rig drilled into the shaft to investigate ground conditions.
- A flat rack container platform supported the small drill rig above the partially filled No. 5 shaft. The platform was suspended from the crane. Staff wore fall arrest equipment attached to a rail above the platform.
A large range of possible relocation sites and transport routes was considered. A geoprobe vehicle investigated the condition of the ground along which the pumphouse may travel. This information allowed geologists to determine how much preparation each section of the route would require.
- In December of 2005 scaffolding was installed inside the pumphouse ready for detailed investigations of the structure and the installation of internal steel beams to brace the building.
Preparing for the move. January to July 2006
A final site and relocation route was determined. The pumphouse will first move south and then travel west to its final location.
- 30 January 2006. With all trees and undergrowth removed, the site was ready for earthworks to commence once archaeological inspections were complete.
- 31 January 2006. Upper level steelwork was welded at Mount Maunganui Engineering’s workshop, and lower level beams were completed at Mount Maunganui and transported to Waihi.
- 2 February 2006. Consulting archaeologist, Ray Hooker unearthed a bottle dump just west of the pumphouse.
- 12 February 2006. Ray Hooker shows local members of Historic Places Trust a selection of the artefacts he has collected. All artefacts were catalogued and recorded. Over a period of two weeks over 250 people took advantage of the opportunity to take guided tours of the site and see the pumphouse close up for the first time in many years.
- 14 February 2006. Lower level beams were welded into place.
- 23 February 2006. Upper level steelwork was bolted into place. These beams provided the internal support for the shell of the structure during the move and remain in place in the new location.
- 3 March 2006. Weak ground to the south of the pumphouse was removed to reveal the building’s original foundations. Underdrains were installed in the area and then it was re-filled with competent material capable of supporting the pumphouse for its ‘step out’ 26.5 metres to the south before beginning its journey approximately 300 metres west to its new home.
Originally, five foundation shafts were dug, timbered and then filled with concrete to provide the base on which to build the pumphouse. The pumphouse was cut from these foundations just above the timbers.
- 12 March 2006. Preparations continued on the route the pumphouse will take. Several weeks of fine weather meant the project was progressing well.
- 13 March 2006. Rafters were lifted into place from the north side. Rafters, steelwork and beams were all modelled on the originals to preserve the integrity of the building.
- 23 March 2006. The ground level to the south of the pumphouse was built back up to its original level using material capable of holding the weight of the building during its move.
- 24 March 2006. Attendees at the 2006 Annual Miners’ Reunion got a close up view of activities on site.
- 5 April 2006. Preload was added to the south of the pumphouse. This material acted as a weight to compress the ground ready for the move. It was removed after measurements confirmed that the route had been compressed sufficiently to hold the almost 2000 tonne weight of the building during transportation.
- 13 April 2006. The pumphouse was illuminated as part of Waihi’s celebration of 100 Years of Rail over Easter weekend.
- 21 April 2006. With scaffolding now removed from the lower level a small excavator was used inside the pumphouse to remove soil and debris from the lower floor under the watchful eye of archaeologist Ray Hooker.
- 9 May 2006. How do you begin to chop a pumphouse off its base? With a very big saw, in this case a diamond-tipped circular saw that is reputed to be the biggest in Australasia. At a later stage of the operation a diamond wire saw will be used.
- 25 May 2006. Autumn rains slowed progress. The ‘step out’ pad was constructed to the south of the pumphouse.
- 2 June 2006. As work neared completion on the ‘step out’ pad, an excavator prepared the causeway adjacent to the old Royal Filling Shaft.
- 8 June 2006. The first two tunnels were cut through the base of the pumphouse. Boxing was built to cast the first two slider beams in situ. Once these were in place the next tunnels were cut and the remaining three beams built.
- 14 June 2006. Steel reinforcing for the slider beam is in place.
- 19 June 2006. Meanwhile the new site for the pumphouse was prepared.
- 22 June 2006. The first two slider beams were poured. A fleet of trucks provided the concrete that was pumped across the site and poured into the boxing, then smoothed off to a tolerance of plus/minus 3 millimetres.
- 4 July 2006. The bottom section of the pumphouse was clamped together using threaded stress bars that were screwed up tight. More internal bracing was added at the lower level. This held everything firmly in place during the move.
- 10 July 2006. The north wall tunnel for slider beam #5 is cut through from inside the pumphouse. Later, when the weight of the pumphouse was supported on all five slider beams.
- 21 July 2006. While work continued on the pumphouse, the precast concrete slider beams were placed on the causeway in readiness for the move. The pumphouse passed over these beams which were then reused and ‘leap-frogged’ down the route ahead of the building by passing them through a trench in the causeway under the building.
- 27 July 2006. After the ‘step out’, at the change point, the tilt and orientation of the pumphouse were corrected before the building was jacked along the causeway.
On the move! 7th August to 8th November 2006
- 7 August 2006. At 6.30 am the building began its epic journey. Four large hydraulic rams pushed the building. Contractors controlled the valves that adjusted the speed and direction of the push.
- 14 August 2006. By the end of the first week the pumphouse had moved just over 22 metres along the 26 metre step out path, and was almost ready to turn slightly in preparation for the journey west. During the week the building featured on TV 1 and TV 3 News, and in many newspapers. A new viewing platform on upper Seddon Street provided a great view for the public.
- 17 August 2006. The pumphouse completed its step out and the western end was rotated to the south to align the building with the causeway. A ram was moved from the north wall to the east wall to assist with the rotation.
- 25 August 2006. Both rams were moved to the west of the building to pull the pumphouse the rest of the way.
- 5 September 2006. After the pumphouse had moved over the slider beams the rear beams were unbolted and jacked to the centre trench under the building. Then they were winched on rollers to the front, jacked into position and reinstalled.
- 16 September 2006. About one third of the distance had been covered. As the pumphouse got nearer to town it was easier for the public to get a good look from the specially set up viewing areas.
- 2 October 2006. Keen as always to assist wherever possible, the Waihi Lions Club lent a hand on a Sunday when the regular crew are not at work. The club is on the lookout for new members and used the photo opportunity provided by the pumphouse move to get this attention grabbing image. Only about 160 metres to go!
- 17 October 2006. Getting closer…
- 24 October 2006. And closer… only three beam moves to go!
- 3 November 2006. Almost there! The pumphouse was now able to be clearly seen from the main street of Waihi, making an imposing sight at night.
- 8 November 2006. Just before sunset, Waihi Gold General Manager Adriaan van Kersen and Golden Legacy Centre Manager Doreen McLeod cut the ribbon to celebrate the building’s arrival. And the ‘grand old lady’ settled in for her first night in her new location, three months and one day after setting out.
- 3 February 2007. Prime Minister Helen Clark and over 750 other guests gathered on site to officially welcome the pumphouse to its new home. Several hundred people also watched the proceedings on a large screen set up nearby.
- July 2007. Landscaping work was undertaken and the area was opened to the public