Waihi Dredging Plant

It was one of only two sites in the North Island where river dredging occurred. Tailings from gold batteries upstream were dredged from the river and reprocessed with cyanide to recover values still present. Much experimentation occurred at this plant, with the technological advancement of air agitation tanks patented worldwide from this site by C. F. Brown between 1902 to 1904. These tanks are the now famous B & M agitation tanks, used all round New Zealand and the world, to treat slimes (very finely ground ore).

In 1908 the plant was purchased by the Waihi Paeroa Gold Extraction Company, which expanded the plant and installed new machinery. After eighteen months of experimentation with grinding and treatment processes, the plant finally proved it could be economically run. Figures for 1909 show that 23,950 tons of tailings were reprocessed and 30 men were employed. On 4 March 1910 a public company was formed, "The Waihi Paeroa Gold Extraction Company Limited", as the management wished to start erecting their new plant at Paeroa. This new plant, with four times the capacity of the Waihi plant, would be modelled exactly on the perfected processes of the old plant. The Waihi plant closed that same year after processing 35,034 tons of tailings for a return of 36,770oz. bullion, valued at £14,615.

The visible remains are contained within a reserve set aside by the Hauraki District Council in 2003.

The water race and tramway are often on privately owned land, but can be seen from the cycleway.

Low Level Water Race

The Low Level Water Race dates from 1897, and was a vital component of the Victoria Battery and the operations of the Waihi Gold Mining Company (and Martha Goldmining Company Ltd. as it became in 1935).

It consisted of a masonry dam constructed on the Ohinemuri River, just down stream from the confluence of the Waitete Stream, and a race to convey the water to the battery site. A fall of 54 feet was obtained at the battery, the water driving two 200 HP turbines. The water race was for the most part an open ground-channel, but crossed the Ohinemuri River twice, in wooden flumed bridges, and was piped across a small gully in a large diameter pipe known as the Siphon. The water race crossed over the tramway twice, and under the tramway once.

The turbines of the low level race drove the stampers at the battery from the outset, and even after the electrification of the battery in 1913, contributed a significant proportion of the horse power required for the stamps. There was a high level water race system as well, capturing the Waitekauri Stream.

Operations at Martha mine ceased in 1952, when the water race was no longer required.

Much remains of this low level water supply. The Masonry dam is still intact, and almost complete. The race is relatively intact over about half its length, and still holds water in several sections.

Martha Mine to Victoria Battery tramway

The tramway, known locally as "The Rake", dates from 1896, and was also a vital component of the operations of the Waihi Gold Mining Company.

This small gauge railway (2ft 9in.) was constructed to connect the mine with the new Victoria Battery at Waikino, a distance of five and three quarter miles (9km).

The tramway alignment remained virtually unchanged for over 55 years. From No. 1, 2, 4, 6 and 7 shafts on Martha Hill it passed close to the No.5 Shaft and Pumphouse, through the town of Waihi, crossed the Ohinemuri River just upstream from the Masonry dam on a bridge known as "Black Bridge", and made its way to the Victoria Battery at Waikino. The line was lowered over a small section to allow the East Coast Main Trunk Railway to pass over it at the eastern end of the Mangatoetoe Bridge.

The tramway is closely associated with the low level Ohinemuri water race, crossing over it once, and under it twice. Two substantial cuttings were required, one clearly showing the water race crossing the tramway.

A total of six steam locomotives had been in service over the life of the tramway. In order of acquisition they were: Ohinemuri, Victoria, Albert, Waikino, Dominion, and Empire.

Each locomotive hauled a load of 40 side-tipping ore filled trucks on the downhill gradient to Waikino, which amounted to about 60 tons of ore to a rake of trucks. This configuration of locomotive and ore trucks was known as a "rake", and hence the tramway was generally called the "rake line". There was a loop in the tramline at the halfway mark to allow one locomotive hauling a full rake to pass the other locomotive returning to Waihi with an empty rake.

All ore processed by the Victoria Battery came via the tramway. The battery had a nominal capacity of 830 tons per day, or 14 rakes, but this figure was as high as 970 tons in 1911, and down to about 500 tons near the end of the battery life.

With the arrival of the "Government Railway" (East Coast Main Trunk) in 1905, a siding allowed for easy transfer to the tramway of coal and other goods bound for Martha and the Company’s other mills. The output of the Victoria Battery, the "black slimes", were transported to the refinery on Union Hill via the tramway also.

Hauraki Rail Trail Cycleway

The map shows both the water race and tramway traces (the water race is the more wiggly line), with waypoints to aid understanding. Touching on the waypoints may open a bubble with a little information. Phones may be better served by loading the gpx file into a GPX viewer, as detailed on the page: GPX files and your phone

33.4 km, n/a