The first 'Big Pump' on the Thames Goldfield was constructed in 1872, by a consortium of mine-owners known as the United Pumping Association. This organisation represented a grouping of four mines that operated on the flat at the northern end of town; often below sea level, and therefore required substantial pumping to keep the mines dry. The functions of the Big Pump were taken over by an even bigger pump – the Thames-Hauraki Pumping Association’s plant at Bella St - around 1895, and the original Big Pump was closed. However, during January 2012, it was to make itself known once more to Thames residents and visitors, as the old shaft subsided, under SH25 at the northern end of town. This was filled in and normal traffic flows resumed on SH25. But wait, there’s more …The Big Pump shaft reopened again during April 2012, and then things really started to get interesting!
The site of the Big Pump was recorded as archaeological site record T12/721, by Dr Neville Ritchie in 1989. This was updated, following the January collapse, and will no doubt be updated again, following the April encore.
The mines on the Thames flat were seldom more than a few metres above sea level and it became necessary to drain them almost from the outset. At first, each mine had its own small pumping plant, which was expensive, inefficient, and incapable of draining water from more than about 200 feet below sea level. As a result, four of the large mines combined their efforts and formed a United Pumping Association. These included the famous Caledonian mine, the richest producer on the Thames field:
'The greatest depth of the Caledonian Company's shaft at present is 300 feet from the surface, or about 210 feet below the level of the sea. It is not considered probable that the gold run will be again found in this level, but men of the greatest experience are satisfied that in the next level it will be met with, and past experience favours the idea that it will prove as rich as ever. …
The machinery of the Caledonian mine, consisting of a forty-five horse power pumping engine and a fourteen horse power winding engine, is ineffectual in keeping the water reduced so far as to permit of the shaft being sunk to a greater depth at present, even with the assistance rendered by the pumping engine of the Tookey Gold Mining Company. Effectual measures have, however, been adopted to drain this reef by the formation of a Pumping Association. The association consists of the Caledonian, Tookey, Imperial Crown, and Golden Crown Companies.
The design was to sink the shaft of the Imperial Crown mine, as this would cut the reef at the greatest depth, and so draw off the water from the other mines. To pump off the water, a large and powerful steam engine is in course of erection, capable of being worked up to 300 horse power. It is a direct acting one, with a cylinder eighty-one and a half inches in diameter, and the pumps will be twenty-five inches in diameter. Massive stone foundations have been laid for this engine. The stone has been procured in large blocks from a valuable quarry discovered on the Hape Creek, within the gold field.'
(Appendix to the Journals of the House of Representatives, 1872 Session I, G-04)
The Daily Southern Cross of 30th October 1871 called the machinery 'The Biggest Pump in Australia'. It noted that it was manufactured by the Union Foundry of Ballarat, and was shipped to Auckland via the port of Williamtown, Melbourne. The cost of the contract (apparently pumping machinery only) was £26,000. The overall capital cost of the project was estimated at £50,000.
The Daily Southern Cross of 16th November 1871 reported: 'The foundation stone for the Pumping Association’s machinery was laid today. There was a slight demonstration.' [Presumably not by anti-mining groups.] The exact date of opening of the Big Pump was not ascertained, but appears to have been some time in early 1872. A Daily Southern Cross article of 6th September 1872 notes that the water levels in mines served by the Big Pump were subsiding.
With the abolition of the provincial government system in 1876, the newly-formed Thames County Council was required to take over financial responsibility for the Big Pump. This became an onerous task, and after mining production started to decline, after 1872, contributions by the 'user' companies became harder to extract. At at least one stage, in January 1879, the County Council withdrew their support, and the pump was closed down. However, this situation was overcome, and the facility reopened in 1880. It continued to work intermittently for about another decade before it was superseded by the formation of the Thames-Hauraki Pumping Association and an even bigger pump at the Bella Street site. The original Big Pump was then closed down and dismantled. (The Thames Star of 22nd January 1909 notes the opposition of a Trustee to the proposed dismantling of the Big Pump chimneys without the consent of the trustees.) (See SRFs T12/716, T12/721 and Isdale 1967 pp. 66-67).
On or about 19th January 2012, a pot-hole developed on State Highway 25, at the northern end of Thames, north the junction of SH25 with Moanataiari Rd. This was quickly identified as a deep hole, and TCDC initiated repair work. During remediation, it was considered likely that this was the site of the Big Pump shaft, and further investigations were made by local historians.
The location of the subsidence is consistent with that of the Big Pump shaft marked on mining maps of the Thames Special Area (see Fig 2 below) and the uncovering of large stone blocks surrounding the shaft is consistent with historical information.
The 'hole' was widened and deepened, revealing extensive stonework around the shaft, was then refilled and the road surface reconstituted. The event revealed information of archaeological value: the exact location of the shaft, pin-pointed by GPS; and the existence and nature of the stone blocks surrounding the shaft.
An article appeared in the Peninsula Press on 26th January 2012
The GPS waypoint of the site (Waypoint 558), as marked by hand-held GPS, was NZTM 1825197E 5887899S.
(An update to the original archaeological site record was drafted by David Wilton, based on contributions from Russell Skeet and John Isdale. The author wasn’t present when the hole was excavated.)
Following the development of yet another large pothole on SH25 at the Big Pump site during April, the road was again closed and traffic diverted. Roading authorities, well prompted by local historians, decided that a more thorough investigation was required this time, and expert resources were called for. This included Opus archaeological consultant Beatrice Hudson, and staff of the Historic Places Trust (HPT). Local historians, including John Isdale, Russell Skeet, and Rob Martinson were also involved; mainly in a research role.
The area around the pothole was excavated to a much greater depth and width than during the January collapse, and this revealed many interesting archaeological features that weren’t apparent earlier. These included the massive extent of the stonework foundations for the Big Pump machinery, which, according to historical resources, penetrated to a depth of 20 feet below ground level (i.e. until bedrock was reached). What are probably parts of the pump were also exposed, including one end of the balance beam and parts of the plunger shaft.
Many locals flocked to the scene, and there were many expressions of interest in keeping the shaft open; for tourism and historical purposes. However, after a period of a few weeks deciding whether or not this was possible, the decision was made to re-cover the shaft and reopen the existing road; all other options being too costly.
A decision was also made that the site would not be subjected to a formal archaeological investigation (or 'dig' as it is commonly known). This was again mainly due to cost, and the amount of time required to obtain necessary consents to modify a recorded archaeological site. However, numerous photos, and a considerable amount of information were obtained, including the type of pump, and the nature of its operation. Also, the size and layout of the facility were interpolated from historical photos and engineering drawings of the pump. Finally, information about the construction engineer and initial manager, William Errington, was obtained. (A brief summary follows.)
So, after 130(+) years hidden, the wonders of this marvellous mining engineering facility were briefly exposed to the light of day, only to be hidden again, supposedly in perpetuity. However, who knows whether or not this old site will once again make itself known to the people of the present-day (whoever and whenever that may be).
The majority of the pumping machinery was built at the Union Foundry of Ballarat, Victoria (the steam cylinder was manufactured by Leigh, of Patricroft, near Manchester, UK), to a design known as the Bull direct-action steam pump. This was different from the traditional design of James Watt, in that the steam cylinder was mounted directly above the mine shaft, and the pump piston and plunger were driven directly downwards, without the rocking beam arrangement used in Watt’s design.
'Bull's designs, overshadowed by his more famous contemporary Watt, were perfected in Cornwall in the late 18th century. The competition between the two brilliant engineers reached the courts, and some believe contributed to Bull's early death.
The two types of engine look very different. The Bull is far more compact - and its admirers argue, more efficient - than the spectacular Watt with its enormous overhead beams. The courts upheld Watt's claim of breach of patent, and in 1795 an injunction was served prohibiting building any more Bull engines. Bull died four years later, aged 39, just before the final judgment that would have imposed punishing fines.
Bull engines were only built again when Watt's patent ran out. One of these has been restored, and can be seen at the London Steam and Water Museum at Kew Bridge, near London. The Kew engine - three stories high and weighing over 100 tonnes - was built in Cornwall in 1856 for the Grand Junction Waterworks Company at 'the awesome cost of £3,000'. From The Guardian (UK) 12 May 2008 article: 'Steam Team's Ebullience Brings Industrial Relic Back to Life.'
With a steam cylinder diameter of 81 inches and a stroke of 10 feet, the Thames pump was amongst the largest Bull pumps built in the 19th century. Working at full capacity, it was capable of lifting 1300 gallons of water per minute, from a depth of 1000 feet. When the Big Pump was put to work in August 1872, it made an immediate difference to below-ground water levels on the field; not just for the four mines for which it was intended. The Daily Southern Cross of 6th September 1872 stated, with respect to the Bright Smile mine (which is some distance to the south of the four UPA mines):
'A marked decrease in the water on the bottom level has taken place since the Association pump started. The decrease is now at the rate of four inches per day. This will soon drain the ground.'
William Errington (1832-1894) was born in South Shields, County Durham, England, and trained as an engineer and draughtsman in the large British engineering firm of Richardson & Co where he acquired the skills that were to make him eminently suited to the pumping projects he tackled in Australia and NZ. He emigrated to Australia in 1854 where he worked as a mining engineer in Ballarat, specialising in the design and construction of large scale steam pumping plants. He also became involved with a large Ballarat iron foundry (the Union Foundry). From there he came to New Zealand in 1871, to install the 'Big Pump' on the Thames Goldfield and remained there for about three years.
In 1874, he was employed to design and install the Auckland water supply pumping system at Western Springs. He also designed a 'graving dock' for the Auckland Harbour Board and later was responsible for the design and construction of Calliope Dock (Devonport), then the largest 'dry dock' in the Southern Hemisphere and which is still in operation. He died in Auckland on 16th December 1894, aged 62.
Further details can be seen at on the Engineering New Zealand website.