Ann: Monax to acquire prospective gold project-MOX.AX, page-52

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Percyville Goldfield

The Percyville Goldfield is situated on the Percy River in the northern part of the Gilberton Geological Sheet area. The gold occurs in reefs near the contact of Precambrian metamorphics with granite, both of which have been intruded by pegmatite and rhyolite dykes. Ball (1915) described the lodes as generally siliceous. The gold reefs average 0.6m in width and some are nearly 0.5km long.

Most workings do not penetrate below the oxidized zone, which is probably 30-45m deep; the deepest workings extended to 152m in the Union Mine. The gold ore contained appreciable amounts of lead, silver, zinc, and copper; one assay at the 30m level of the Homeward Bound Mines was 560 grams/tonne (15½ oz per tonne) Silver, 45 grams/tonne (1¼ oz per ton) Gold, 13% Lead, 2% Copper.

Total production from 1912 to 1917 on the Percyville Goldfield was 2,080 tonnes of ore, which yielded 150kg (3,950 oz) gold, 400kg (10,334 oz) silver, and 90 tonnes copper; 13 tonnes of lead were won in 1912. The largest production from any one mine was 105kg (2,800 oz) of gold from the Union Mine. The primary ore averaged 20 to 25 percent copper and 220 to 260 grams/tonne (6 to 7 oz per tonne) of gold, with exceptional small rich patches containing 3,700 grams/tonne (100 oz/tonne) gold.

Gold has also been mined from quartz reefs in the Proterozoic granite at Mount Hogan in the headwaters of Granite Creek in the north-east. No information is available on the size of the reefs. Jack and Etheridge recorded production of 170 kg (4,500 oz) of gold averaging 65 grams/tonne (1¾ oz per ton) from 1885 to 1890.

Gold averaging 75 to 110 grams/tonne (2 to 3 oz per ton) was mined at Mount Moran, 3km north of Ortona copper mine near the northern boundary of the Geological Sheet area. Gold was obtained from quartz veins in weathered and leached dolerite dykes between depths of 15m and 90m, below a cover of Cretaceous sediments. The Mount Moran Mine should not be confused with Mount Moran, a prominent peak in the Mount Hogan goldfield.

EINASLEIGH AREA

Kidston – The Oaks Goldfield

Kidston (42km south of Einasleigh) also called “The Oaks.” About 75,000 oz of gold have been won from the Oaks Goldfield, 1.6km west of Kidston. Gold was discovered here in 1907 and mined till 1942. The most comprehensive description of the Oaks Goldfield is that by Marks in his geological report. The gold is found in quartz veins and altered and crushed zones of the Forsayth Granite. Large bodies of low-grade gold ore have subsequently been worked by open-cuts, chiefly at Wises Knob.

More recent attention has been towards working of groups of small leaders. Operations were facilitated by the existence of a State battery now out of commission. Kidston forms a centre for outlying areas to the south, at which wolfram, scheelite and gold-copper have been worked. Less important occurrences of gold are apparently associated with quartz porphyry in Balcooma Creek.