Bonanza Mine (Lot's Wife), Otago Region, New Zealandi

Regional Level Types
Bonanza Mine (Lot's Wife)	Mine
Otago Region	Region
New Zealand	Country

Abandoned gold mine.

The Bonanza Mine site is at an isolated location, 7 kilometres east of Nenthorn (itself nothing but a stone cottage ruin), and approximately 10 kilometres south-west of Stoneburn. While information is lumped historically with Nenthorn, the mine occupied its own lode, separate from the Nenthorn goldfield. Modern sources call is Lot's Wife after a small hill at the location, although it would make a good name for a salt mine.

The mine occupies part of a bleak tussock grassed plateau in the vicinity of the hill, and a deep gully incised into the landscape called Back Creek. The site appears to be on a private pastoral station, and access requires miles of faint station tracks. Little appears to remain at the site.

There are three parallel north north-west to east south-east trending lodes called Bonanza 1, Bonanza 2, and Zedd lodes. Recent investigations found evidence of shallow open cuts, and one shaft. The lodes are hosted by north-west trending normal faults, containing silicified breccia, and discontinuous quartz veins, up to 2 metres wide. The quartz infills cavities with prismatic crystals often stained brown from near surface oxidation minerals. Arsenopyrite, pyrite, ankerite, and muscovite are found in the shears near the vein margins.

Gold was discovered here in 1890 by the Phelan brothers, pegging 60 acres, and mining occurred until the late 1890's. Around 2,000 ounces of gold was obtained. Glass Earth Gold Limited drilled the site in 2010, failing to find economic mineralisation. An Otago University study of the site in 2016, found only minor evidence of gold in the veins.

The mine was developed by the two Phelan brothers, and Arthur Kitchener,
as the Bonanza Gold Mining Company Limited, with J. Smith initially as mine manager. The abundance of pyrites, lack of water, and later lack of gold bearing stone all hampered the mine. Initially the mine produced good results, and shareholders obtained double the money invested into it.

Arthur Kitchener writes in 1890, an initial test crushing was sent to Dunedin, assaying at one ounce to the tonne. Some months followed prospecting, and 100 tonnes was extracted from shallow open cuts, with seven tonnes from richer patches bagged for initial treatment. They purchased a small Huntingdon mill.

The initial mill is purchased, and removed to the Prospectors Mine at Nenthorn in September 1890, and is replaced with a new mill, equivalent to five stamps. Mine manager, J. Smith leaves at the end of 1890, to purchase and operate the Croesus Mine at Nenthorn with William McKay.

A lot of underground work is noted early 1894, with little good stone. The shareholders at this stage come from all one family, and decide to sell the mine mid 1894 for 850 pounds. It is assumed the Phelans share is not sold, as they continue to operate the mine until 1898. Patrick Phelan dies May 1896.

At some point around 1896, the New Zealand Minerals Company hold the mine on tribute, with an option to purchase but decline.

The mine was sold in 1898 by the Phelans, to 'some Dunedin people', after 1500 pounds was spent on low level development work, finding only limited ore of value. The mine is found to be closed at the end of 1898, and no more activity was found.

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