|Latitude & Longitude (WGS84):||32° 43' 59'' South , 116° 22' 0'' East|
|Latitude & Longitude (decimal):||-32.73333,116.36667|
|Owned/operated by:||Newmont Mining Corporation (100%)|
|Köppen climate type:||Csa : Hot-summer Mediterranean climate|
An openpit gold mine located 130 km SE of Perth, in the northeastern jarrah forest, 12 km from the town of Boddington. The mine was a joint venture owned by Newmont Mining Corporation and AngloGold Ashanti.
Production ceased in 2001. In 2009 Newmont purchased AngloGold Ashanti's shares to become the sole owner.
A 1979 survey identified an anomaly in the Saddleback Greenstone Belt. A large open cut operation commenced in 1987, and ceased in 2001, after the known oxide ore resource had been processed. The mine was jointly owned by Normandy Mining, Acacia Resources, and Newcrest Mining. At the time it was the largest gold operation in Australia.
After an extended period the mine was acquired by Newmont Mining, who identified a gold bedrock resource to the north of the original pit. Two pits were opened in 2010, and again forms Australia's largest gold mine (2012), as far as the production of gold. It has estimated reserves of 20 million ounces of gold, and copper production of 30 000 tonnes per year. The estimated life of the mine is 25 years.
The Saddleback Greenstone Belt is a fault bounded sliver of Archaean volcanic and shallow level intrusive rocks, surrounded by granitic and gneissic rocks. The main zone of gold mineralisation occurs reasonably continuously over a strike length of about 5 kilometres long and 1 kilometre wide. This mineralisation forms a semi continuous blanket within the upper iron rich laterite, with more eratic gold distribution in the lower zones. The basement rocks below the oxide zone has gold mineralisation with predominantly andesitic volcanics and diorite dykes. In the primary ore gold is present in millimetre to centimetre scale veinlets in quartz epidote/clinozoisite actinolite.
Gold in the higher grade secondary zone from the base upwards is:
1. Saprolite zone (1-5 metres) of green clay.
2. Clay Zone (30-100 metres)of light brown to white oxidised kaolinitic clay.
3. Laterite Zone (4-10 metres) dark red to brown laterite, mainly gibbsite.
In the primary diorite host the gold is found in dense quartz veins, and surrounding alteration haloes. Relic quartz veins persist in the overlying laterite zone. The gold is closely associated with copper minerals. In the upper levels is malachite and cuprite, intermediate levels chalcocite and native copper, and the lowest level of the weathered zone is chalcopyrite.
A small number of high quality, non gold specimens were recovered during the early days of exploration by enlightened geologist Roger Staley. These were donated to the Brisbane Mineral Museum, who off-loaded some spare specimens onto the collectors market. Copper specimens are usually free of matrix and cleaned of patina. The southern pit the specimens came from is now back-filled with the overlying bauxite ore, and rehabilitated.
During the early stages of the original mining period, white quartz with visible veins of gold were found in one section. Three specimens were studied by the Western Australian Chemical Laboratories in 1993. On one specimen the new species Saddlebackite was found in association with the gold.
49 valid minerals. 1 (TL) - type locality of valid minerals.
Rock Types Recorded
Select Rock List TypeAlphabetical List Tree Diagram
Entries shown in red are rocks recorded for this region.
- Igneous rock
- Sedimentary rock and sediment
- Metamorphic rock
- Superficial deposit
GeochronologyMineralization age: Neoarchean : 2724 Ma to 2595 Ma
Important note: This table is based only on rock and mineral ages recorded below 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|
This geological map and associated information on rock units at or nearby to the coordinates given for this locality is based on relatively small scale geological maps provided by various national Geological Surveys. This does not necessarily represent the complete geology at this locality but it gives a background for the region in which it is found.
Click on geological units on the map for more information. Click here to view full-screen map on Macrostrat.org
0 - 66 Ma
|ferruginous duricrust 38498|
Age: Cenozoic (0 - 66 Ma)
Description: Ferruginous duricrust, laterite; pisolitic, nodular, vuggy; may include massive to pisolitic ferruginous subsoil, mottled clays, magnesite, reworked products of ferruginous and siliceous duricrusts, calcrete, gossan; residual ferruginous saprolite
Comments: regolith; synthesis of multiple published descriptions
Reference: Raymond, O.L., Liu, S., Gallagher, R., Zhang, W., Highet, L.M. Surface Geology of Australia 1:1 million scale dataset 2012 edition. Commonwealth of Australia (Geoscience Australia). 
|Neoarchean - Mesoarchean|
2500 - 3200 Ma
|Archean crystalline metamorphic rocks|
Age: Archean (2500 - 3200 Ma)
Comments: Yilgarn Craton
Reference: Chorlton, L.B. Generalized geology of the world: bedrock domains and major faults in GIS format: a small-scale world geology map with an extended geological attribute database. doi: 10.4095/223767. Geological Survey of Canada, Open File 5529.