Mount Pleasant Gold Mine, Peak Hill Mining District, Meekatharra Shire, Western Australia, Australiai

Regional Level Types
Mount Pleasant Gold Mine	Mine
Peak Hill Mining District	Mining District
Meekatharra Shire	Shire
Western Australia	State
Australia	Country

(Map- Google Maps incorrectly locates the former town site of Peak Hill. It is 3 kilometres north-west of the Mount Pleasant Gold Mine)


The site is marked by a shallow small open pit, about 3 kilometres south-east from the former Peak Hill townsite and Main pit.

It was initially mined around 1900, producing a substantial 8,000 tonnes according to the source at 9 g/t Au. Mining resumed in the 1970's and 1980's producing 146,000 tonnes of ore at 3 g/t Au.

The ore zones are flat lying, and emplaced sub-parallel one above the other. The gold is hosted in quartz-carbonate veins, with associated alteration zones of albite, ferriginuous rich chlorite, sericite, carbonate and pyrite, along with zones of black graphitic schist. The veins are vertical or saddle shaped type in anticlinal folds. Geologist studying the deposit called the base the Core Sequence showing in the pit as 55 metres thick. Above this is the Honey Quartzite of ribbon quartz, then the Intermediate Sequence.

The Core Sequence consists of quartz-biotite-carbonate-muscovite, and more minor epidote, hornblende, garnet, magnetite, and pyrite. There was also locally abundant fine zircons and monazite in the biotite rich areas. The graphitic schist is associated with a zone of chlorite-biotite-garnet schist, with albite porphyroblasts, containing inclusions of zircon and monazite.

The Intermediate Sequence is quartz-muscovite schist, with minor plagioclase, biotite, microline, carbonate and chlorite. The lower part of this sequence shows biotite schist with garnet and epidote. Above this is the Mine Sequence of biotite-muscovite, and more minor chlorite, carbonate, amphibolite, garnet and albite schist, and graphite schist. The sequence is 40-50 metres thick.

Above this is the Marker Quartzite of recrystallised quartz mylonite, 1 to 3 metres thick. It contains iron oxide radiating pseudomorphs after acicular crystals as grunerite, and iron oxide pseudomorphs after porphyroblasts as possibly garnet.

The Hanging Wall Sequence is 700 metres thick of muscovite-magnetite-garnet-chlorite, with mafic schist and metabasite. The metabasite is locally garnetiferous with hornblende, plagioclase, quartz, garnet, epidote and titanate.

Other Regions, Features and Areas containing this locality

References