Olivewood Gold Mine (Olive Wood Mine; One-Oh-Two; One-Oh-Three; Havelock; Orlando East; 102 prospect), Tennant Creek, Barkly Region, Northern Territory, Australiai

Regional Level Types
Olivewood Gold Mine (Olive Wood Mine; One-Oh-Two; One-Oh-Three; Havelock; Orlando East; 102 prospect)	Mine
Tennant Creek	Creek
Barkly Region	Region
Northern Territory	Territory
Australia	Country

These locations have been combined, as the sources tend to describe the whole area as one. They are 28 kilometres north-west of Tennant Creek, between the Orlando and Gecko mines.

Olivewood (or Olive Wood) forms the most extensive historic workings, and as such has been used as the main heading. The mine produced 267 tonnes of ore at 15.7 g/t Au, or in another source 263 tonnes at 10.26 dwt. Bonzle names the Olivewood and Havelock mines as the same location, which is incorrect.

A few hundred metres to the north-east is One-Oh-Two (or 102), with two further un-named groups of workings between. The mine is said to be on a steep south-east trending ridge capped with ironstone, with a small 3 metre deep historic pit. Elliston in 1959 got very excited about bladed hematite at the location forming cellular boxworks.

Havelock is a few hundred metres north of Olivewood, or north north-east of One-Oh-Two, consisting of a shaft and several small pits. This was worked in the 1930's producing 58 tonnes of ore for 139 ounces of gold, or in another source 57 tonnes at 8.5 dwt. No further historic information was found for any of the sites.

Orlando East is south of the above mines by a few hundred metres, containing some workings only a few metres deep. One-Oh-Three is mentioned as an anomaly near One-Oh-Two by a 1959 source shortly after its discovery. It is probably referred to in later sources, but remained un-named by this stage.

There are three north-west to south-east shear zones, Havelock being on the Havelock Shear Zone, Olivewood/One-Oh-Two on the Olivewood-102 Shear Zone, with the Orlando East Shear Zone to the south. In turn they are all between the parallel Orlando Shear Zone to the south, and Gecko Shear Zone to the north.

Geology tends to mention species, then confusion about its structural relationship. Generally poor mineralisation was found, with the possible exception of Orlando East. Geopeko drilled the deposit between 1970 to 1988, with 6 holes, but it appears all failed for various reasons. North Flinders Mines investigated 1992-1994 with 72 holes drilled close to the Olivewood/One-Oh-Two workings. They determined two ironstone bodies at Olivewood/One-Oh-Two they named Western and Main, with at best patchy mineralisation.

The largest ironstone body is called the Olivewood Trig Ironstone at 90 x 10 metres. This is non gossanous lenticular dense black magnetite-hematite ironstone, with minor quartz veining. The shear zone contains multiple hematite-magnetite pods in a quartz-hematite matrix, with common specular hematite.

Siltstone, greywacke and shale is folded along north-west trending axes of the three shear zones. Small hematite-quartz ironstone lenses commonly outcrop in the Olivewood-102 Shear Zone. Fine grained turbitite red-brown siltstone and greywacke is found, altered to dark red-brown hematite (after chlorite), with specular hematite stringers. The Olivewood-102 Shear is 2 kilometres long, and displaced by a number of north north-west and north-east faults.

Archibald attempted largely without success to interpret the structures at One-Oh-Two. He states outcropping is absent, but sub-outcropping is relatively common. The dip and strike was impossible to define, and trend were variable, or to distinguish between sheared porphyry and sheared sediment. Faulting and shearing had re-orientated the strata. There is a large conjugate north-east and north-west fault set cutting the Olivewood/One-Oh-Two ridge, which he suggest has played a role in the re-orientation, and difficulties in interpreting the site. This unco-operative location only proves geologists should be paid more.

The Orlando East Shear is noted as lacking magnetite, but with nearby quartz-feldspar porphyries. Outcropping is lacking. Gold and bismuth mineralisation is associated with sheared hematitic siltstone, adjacent to sheared quartz-feldspar porphyry. Rock chip sampling achieved a highest grade of 7.39 g/t Au, 133 ppm copper and 592 ppm bismuth.

Havelock was explored with 273 drill holes, finding only weak gold, copper and bismuth anomalies.

References

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