Monowai Mine, Waiomu, Thames-Coromandel District, Waikato Region, New Zealandi

Regional Level Types
Monowai Mine	Mine
Waiomu	- not defined -
Thames-Coromandel District	District
Waikato Region	Region
New Zealand	Country

An epithermal gold and silver mine operated from 1891 to 1915 producing 1,240 kg of bullion. Noted for presence of native gold and tellurides. Associated with Pb-Zn-Cu sulphides in the late stage quartz veins.

The early details were not found, and the first mention of the mine is in 1895 as the Monowai Amalgamated Company. In 1896, the Monowai Gold Mining Company of New Zealand was formed with English capital. The company was reconstructed in 1901 as the Monowai Gold Mines Company. It was reported the mine and battery was to be sold in 1904.

This was purchased by the newly formed New Monowai Gold Mining Company. This company in 1909 was wound up, and a new company formed, named the Monowai Gold Mining Company Limited. In 1916, the Monowai Gold Mining Company was placed in voluntary liquidation with plans to auction off the lease and plant.

In 1899, local landowner R.R. Otter sued the Monowai Gold Mines Limited for polluting the Waiomu Stream with cyanide and other chemicals. All fish life in the stream had been killed off, although there was little thought at the time for such environmental disasters. Otter was more concerned about the lack of drinking water for his stock. The company countered that it had posted signs before operations warning it was about to dump cyanide into the stream. This weak defence saw the warden's court award Otter some money, and an injunction against further pollution. However this could easily be overridden by the government declaring the stream a sludge channel under the mining act, effectively allowing mining companies to dump tailings, chemicals, and anything else they liked into the water course with impunity.

The Ferguson Mining and Smelting Company was working the mine under an option to purchase in the early 20th Century. They built a new type of battery from the U.S.A. that involved heating the ore to extreme temperatures to release the gold. After 18 months of construction, the plant operated for only two months before closing. It is said while the opening celebrations for the plant was taking place, the directors were holding a meeting in the office discussing the disposal plan for the treatment plant with scrap merchants.

The Monowai Gold Copper and Lead Mines Limited was formed in Auckland in 1932, to acquire the Zeehan, Monowai, Broken Hill, and other claims in the immediate area from the Waiomu Sulphide Company. They planned to conduct some development work, however by 1933 they were in the warden's court with a former Monowai mine manager requesting forfeiture for non compliance of labour conditions, and generally showing a lack of interest. The company by this stage was in liquidation. The Monowai Gold Developments Limited was mentioned briefly in 1937.

The large reef was on a spur between the Paroquet and Comstock streams, on the northern slopes of the Waiomu valley. The reef strikes north-east, dips 60 degrees west, an average width of 20 feet, following a fault fissure, accessed by four adits ranging from 113 to 1,380 feet long. The lode across included a clay section, then hard flinty sparsely mineralised quartz, another clay section, then the main mineralised white quartz vein with disseminated mixed sulphides, and small irregular quartz lenses, and finally a quartz and country rock intermixed section with a few pockets of sulphides with no clear Hanging Wall.

The vein was wedged shaped being wider at depth. The profitable pay shoot was only 150 feet long. The sulphides include pyrite, galena, sphalerite, chalcopyrite, electrum, and various minor tellurides, bismuth, and antimony. Occasional secondary un-named species are found. The sulphides are complex, and historically led to much of the gold-silver values going to the tailings. The richest ore was found in dark complex sulphide patches often in the vicinity of quartz cavities in finely crystalline granular quartz in the upper sections of the reef.

Various plans have been put forward to re-open the mine from the 1970's, usually opposed by local groups. The old battery site is part of a walk up the Waiomu valley to a Kauri tree location. Little remains. Various adits are in the hills above, with waste rock covering the hill side below each one, although are not easily accessible.

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