Endeavour Inlet Mine, Marlborough Sounds, Marlborough Region, New Zealandi

Regional Level Types
Endeavour Inlet Mine	Mine
Marlborough Sounds	- not defined -
Marlborough Region	Region
New Zealand	Country

Stibnite-rich mesothermal quartz vein system hosted in a km scale shear zone in metasedimentary schist.

Historic antimony smelter slags contain pyrrhotite and native antimony.

Named by Captain Cook after his ship when he anchored in the bay.

Mineralisation is found in quartz veins over a 300-350 metre zone at the southern end of the Endeavour Fault, which extends from Guard Bay in the north to Endeavour Inlet in the south. The quartz veins are en echelon, variable thickness 0.2 to 1.9 metres, variable strike lengths 0.5 to 65 metres, and dip 60-70 degrees east. Cross faults commonly displace the veins.

Massive stibnite is found at shallow levels, while at deeper levels is arsenopyrite-pyrite-marcasite-gold. Yellowish cervantite is a weathering product of stibnite, seen as stains and patches on the oxidising ore pile. Antimony ochre, metallic antimony, pyrrhotite, senarmontite, kermesite, and trace gold, with stibnite, arsenopyrite, and pyrite values have also been found on the piles. Alteration around veins include sericite, carbonate and abundant iron oxides.

Stibnite is found filling tension gashes, and replacing quartz, while crushed dark grey arsenopyrite-pyrite in well defined linear zones, but also disseminated. Locally marcasite is found in this zone, and trace amounts of tentatively identified tetrahedrite. Two specimens studied contained possibly scheelite-wollastonite intergrowths, in patches and veinlets.

A marked side track from the Queen Charlotte Track goes to the former smelter site, with waste rock piles, then further up the hillside some of the drives can be seen, and then a steep walk to the No. 1 cut on the saddle between Endeavour Inlet and Port Gore. Accommodation is available at the inlet.

In 1873, ore containing 60% antimony was discovered in a landslide on the saddle between Endeavour Inlet and Port Gore by John Ashworth. He formed locally the Marlborough Antimony Company Limited, and mining began in 1874, with a smelter erected 1875. A small amount of gold was being produced as a side product to the antimony. After a short time the enterprise closed. Ashworth tried again in 1877 to re-open the mine, without success.

The Endeavour Inlet Antimony Company was formed by Houston Logan of Wellington in 1883, and mined the No. 1 level at the saddle, and two lower levels. A smelter was established lower down the hill near the head of the inlet. It was reconstructed as the New Zealand Antimony Company, with English capital in 1888, and developed levels 4-7, however antimony grades were poor. The company went into voluntary liquidation in 1892.

Almost immediately the small local Star Antimony Company was formed, which survived until July 1901. The former mine manager Jaketh Wearne made several attempts to re-open the mine without success, and in 1907 after losing a court battle over the mine committed suicide in the mine assay office, by swallowing concentrated hydro-chloric acid.

Efforts to re-open the mine between 1927-1932 failed. Companies have explored the deposit until recent times.

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