How is the ore mined?Because the ore body at Cannington is deep below the surface, the underground method of mining was chosen. Access to the underground mine is via a decline. This is a tunnel 5.2 m wide and 5.5 m high, sloping underground from the surface, allowing vehicles and mine employees to access the mine workings. |
Mine vehicle emerging from the entrance to the decline. |
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The ore body is mined using the stoping technique. Holes are drilled into ore-bearing areas from various underground levels. The drill holes are then packed with explosives. Blasting fractures a huge volume of ore-bearing rock called a stope, which is similar in size to a multistorey office block with the shape of an upside-down milk carton. The stope now consists of large fragments and lumps of broken-up rock. |
Underground drill rig preparing an ore face for blasting. |
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Special front-end loaders called boggers scoop up the fractured ore from access tunnels below the stopes, and load it onto Load Haulage Dumps (LHDs). These are special underground trucks that transport the ore to nearby vertical tubes called the ore passes. |
Bogger scooping up fractured ore after blasting of a stope. |
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The ore is tipped into the ore passes and falls to deeper parts of the mine (575 m below the surface) where it is transferred onto an ore conveyer. This transports the ore to a jaw crusher that crunches it to a finer size between two huge steel plates. This is called primary crushing. |
The headframe at Cannington. |
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Following primary crushing the ore is placed in a skip that is lifted by a hoist to the head frame on the surface. Each skip-load is about 9 tonnes of ore. The ore is then transferred into ore trucks that carry it to the ore stockpile to await processing. |
Fully laden truck transporting crushed ore from the headframe to the ore stockpile. |
