Historic Significance

Historical Significance or Value This historic place was registered under the Historic Places Act 1993. The following text is from the original Historic Place Assessment Under Section 23 Criteria report considered by the NZHPT Board at the time of registration. Historical: Gold extraction by means of dredging was unusual in the North Island, where it was confined to a handful of sites in the Waihi/Paeroa area. The government's development of the cyanide method of gold extraction during the late 1880s had encouraged the formation of small concerns to reopen earlier Ohinemuri gold mines. One such venture was the Ohinemuri River Syndicate, which between 1897 and 1903 took up a number of sites at Owharoa. On a later lease, the greater part of the Ohinemuri River, the ORS used to reprocess tailings from earlier operations. Using small suction dredges and barges, the company raised the tailings washed into the river from older sites, treated them and discharged them back into the river after extracting the gold. The company sold out in 1908 to a more efficient operator, who managed to sustain operations for another decade until 1918 when it went into liquidation, its demise hastened by a flood which deposited thousands of tonnes of silt and sand on the tailings. This operator established the Waihi-Paeroa Gold Extraction Works at Mill Road on the lower reaches of the Ohinemuri River in 1912. Between 1913 and 1918 the company extracted £276,211, but spent £320,000 in doing so.

Physical Significance

This historic place was registered under the Historic Places Act 1993. The following text is from the original Historic Place Assessment Under Section 23 Criteria report considered by the NZHPT Board at the time of registration. The Waihi-Paeroa Gold Extraction Company Limited Works site is significant both for historical reasons, and for the innovative thinking behind its operation. The company which established the plant (and its predecessor near Waihi, and also the Judd plant at Thames) realised: 1. That a lot of fine gold was being (or had been previously) discharged into rivers along with the crushed waste rock in the form of sludge. 2. That at least a portion of the lost gold could be successfully recovered by the application of established and new technologies (dredging and the cyanide process). In the event the Company did recover gold from mine waste, or sludge, which had been discharged and otherwise lost in waterways. Although tailings on land were frequently reworked, the recovery of discharged mine sludge from waterways by dredging, and its reprocessing was unheard of in New Zealand previously. Architectural: The gold extraction works site at Mill Road, Paeroa, consists of at least five identified industrial building remains. The layout of the place reflects the pragmatic approach of industrial engineers to matters of design, where function is paramount.

Detail Of Assessed Criteria

This historic place was registered under the Historic Places Act 1993. The following text is from the original Historic Place Assessment Under Section 23 Criteria report considered by the NZHPT Board at the time of registration. b) The association of the place with events, persons, or ideas of importance in New Zealand history: Events: The Mill Road complex's history is well documented. Between its construction in 1911/12 and its inundation by flood waters in 1918, it processed some 907,428 tonnes of tailings. Persons: Little is known about the people associated with this place. The AJHR records R.M. Aitken as manager in 1913. Ideas: Gold extraction played an important part in the economic history of New Zealand, transforming the provinces of Otago and Westland and assuming significance in the Hauraki/Coromandel during the latter half of the 19th century. The Hauraki/Coromandel goldfields were the only large payable field in the North Island. This place is important because it represents the rare application of dredging technology to a North island site, where quartz extraction was more important than alluvial mining or dredging. (c) The potential of the place to provide knowledge of New Zealand history: Technically speaking, this place does meet the definition of an archaeological site as set out under S 2(a) (b) of the Historic Places Act 1993. However, in his 1990 survey of Thames/Ohinemuri goldfield sites, archaeologists Nevill Ritchie gave Mill Road a 'medium' assessment. He stated: The remains of the Waihi Dredging Plant are limited and in very dilapidated and ruinous state, to the point where there is little left to interpret. However, at some future date it may be worth erecting some form of interpretation, incorporating one or more of the historic photographs ... The remains on the Paeroa site are much more substantial and less modified. Together with its easier public access, it is a prime sit for public interpretation. There is no record of the dredges, launches or barges having survived. (j) The importance of identifying rare types of historic places: Dredging was essentially a South island phenomenon. Ritchie states that the Waihi and Paeroa plants "and the Judd plant at Thames (of which no trace exists), represent the only attempts at gold dredging in the North Island". Since all traces of the Judd plant have disappeared and the Waihi remains are less intact than Paeroa, the Mill Road site must be considered the most potentially useful of these three. That said, however, it must be acknowledged that these small operations were far less important to the history of New Zealand gold mining than their southern counterparts. (g) The technical accomplishment or value, or design of the place: DATE: 1910 ARCHITECT: Not known STYLE CODE: Not applicable DESIGN: The gold extraction works site at Paeroa is an important physical reminder of the mining boom in the Coromandel/Thames/Hauraki area at the turn of the century. It also represents physical evidence of one gold extraction operation that did not reap rich rewards for its owners. The identified industrial remains which make up the site were designed and built in a convenient arrangement beside the lower reaches of the Ohinemuri River in order to facilitate the various processes of removing river sludge from barges, grinding the sludge into fine sand, and treating the sand with cyanide to recover the gold and silver. The logical layout of (1) the remains of storage tanks beside the river (2) foundations of the engine room (3) cyanide tanks (4) the remains of grinding or "tube" mills, and (5) the site of the condenser ponds, can still be seen to reflect the mining engineer's "form follows function" approach to design. (m) Such additional criteria not inconsistent with those in paragraphs (a) to (k): There are 18 registered gold mining structures nationally. Of these, the Register currently contains 14 historic places associated with the gold mining history of the Thames-Paeroa-Waihi district. Six are category I, eight Category II. The remains of the Paeroa gold extraction works next to the Ohinemuri River are comparable in design quality to existing Category II mining ruins and structures such as the Catherine Mine Machinery Foundations, Coromandel, Category II, or the Crown Battery Site Ruins, Karangahake, Category I. The Mill Road site was short-lived and was not a major producer to the extent of the Waihi mines. It was, however, a rarity, a dredging operation in a predominantly quartz crushing district. For that reason, although the dredging plant has not survived, the Waihi-Paeroa Gold Extraction Co. Mill Road plant site merits registration as a Category II historic place.