Kalgoorlie Consolidated Gold Mines, Kalgoorlie-Boulder, Kalgoorlie-Boulder Shire, Western Australia, Australiai

Regional Level Types
Kalgoorlie Consolidated Gold Mines	Group of Mines
Kalgoorlie-Boulder	- not defined -
Kalgoorlie-Boulder Shire	Shire
Western Australia	State
Australia	Country

A group of gold mines essentially developed on one major gold deposit, now mostly incorporated into one large open pit, currently operating.

One of the largest mesozonal gold deposits in the world, contains >1,457 tonnes Au. Ca. 20% of it occurs as tellurides.

The Golden Mile is located on the eastern edge of Kalgoorlie-Boulder. Paddy Hannan discovered gold here in 1893. It led to one of the largest gold rushes in Australia's history. After a couple of years when the alluvial gold had been exhausted, companies were floated in London to mine the reef gold. This continued through the Twentieth Century, with the initial large number of mines gradually consolidated until 1989, when only one lease remained covering the entire field. At this point, the Fimiston Superpit was developed. Some geology information from modern studies is under this locality.

Specimens outside of museums from the initial mining days would be rare, as most was destroyed to extract the gold. In 1903, the British Museum studied its collection of tellurides from the Golden Mile. Of 48 specimens studied, 29 contained calaverite, 10 sylvanite or possibly krennerite, 14 petzite, 28 coloradorite, and 3 altaite. 25 samples showed more than one telluride on the same specimen, and 11 had 3 different kinds.

Calaverite was the first to be discovered at the Golden Mile by Richard Eades (Simpson Minerals of W.A. 1948) in 1896, and is considered the most abundant and richest in gold of the tellurides. The museum had specimens of considerable size, including one from the Associated Gold Mine 63cm x 18cm. They were described as bronze-yellow in colour with a bright metallic lustre.

Sylvanite was less common, silver white in colour with a brilliant lustre. While no crystals were available at the time, E.S. Simpson described krennerite from crystals seen at the Kalgurli Mine. The museum describes petzite from the samples as iron black, with a metallic lustre. Coloradoite as abundant, iron black with a marked conchoidal fracture. The first record of altaite in Western Australia came from the Great Boulder Proprietary Mine, as yellow-grey coloured sometimes with a yellowish tarnish, and three perfect cleavages at right angles to each other.

Other minerals with the tellurides were also noted. Gold was described as loosely fine crystallised aggregates (sponge gold), yellow ocherous coloured (mustard gold), and bright films (paint gold). The Great Proprietary Mine found 70 pounds of sponge gold in a single pocket. There was also abundant thicker, more lumpy masses of gold in the specimens.

Also found was fahlerz, an old name for a point in the tennantite-
tetrahedrite series, resembling petzite and coloradoite at the location, but a darker iron-black, dull, with a black streak. The massive mineral was found in small patches on four specimens.

Four crystals, 1cm across,of magnetite was found on one specimen from the Kalgurli Mine. Calcite on one specimen from the Hannans Block 45 Mine. Dolomite on most of the specimens as grey compact bands interfoliated with the greenish schist. Small schorl needles 2-3mm in length embedded in iron pyrite and rock. Very minor chalcopyrite in coloradoite in one specimen. Fibrous gypsum veins penetrating the rock of one specimen.

The matrix was described as pale greenish sericite schist with a silvery reflection. Minute grains and crystals of iron pyrites were scattered through most specimens, however tellurides were embedded in the schist as irregular masses of variable sizes, but did not impregnate the rocks as fine grains. Chlorite was common as darker green material, and bands of grey granular dolomite. Ilmenite was noted on one specimen, largely altered to leucoxene, with a knotted appearance.

Altered rocks from the upper portion of the lode are soft, clayey and yellow but retain their schistose character. Only limonite and fine grained gold was found. The reference notes several other species claimed by other sources, but not identified in its study, including emmonsite, silver chloride, native tellurium, roscoelite, hessite, amalgam, and native mercury.

Kalgoorlite and Coolgardite were announced as new species in 1898 and 1901 respectively, but by 1903 these were proven to be combinations of known tellurides rather than a new species. In 2016, the similarly named Kalgoorlieite was announced as a new species by the IMA, discovered by Kirsten Rempel and Christopher Stanley, from existing telluride specimens held by the School of Mines Kalgoorlie. Kalgoorlieite is microscopic small grain sized material, as the fourth known oxygen-free As-Te mineral.

More geology information under 'Kalgoorlie-Boulder' and 'Fimiston Open Pit (Superpit)'.

Geochronology

Mineralization age: Neoarchean : 2629 ± 9 Ma

Important note: This table is based only on rock and mineral ages recorded on mindat.org for this locality and is not necessarily a complete representation of the geochronology, but does give an indication of possible mineralization events relevant to this locality. As more age information is added this table may expand in the future. A break in the table simply indicates a lack of data entered here, not necessarily a break in the geologic sequence. Grey background entries are from different, related, localities.

Geologic Time				Rocks, Minerals and Events
Precambrian
	Archean
		Neoarchean		ⓘ Muscovite 2629 ± 9 Ma

Localities in this Region

Other Regions, Features and Areas containing this locality

References