Read on to find out more about how gold and silver are mined and extracted at Henty.
There were originally two ore bodies discovered at Henty. The first, the Sill Zone has now been entirely mined out. The second, Zone 96, is 400m underground and is currently being mined. It is an underground operation because its great depth would have meant removal of enormous quantities of waste rock (rock with no ore minerals) if mined by the open cut method. This would have created a very large open pit in an environmentally sensitive area.
The entrance to the decline which gives vehicle access to the underground workings.
The Henty operation is currently being expanded to enable mining of a newly discovered ore body nearby, called the Mt Julia ore body.
Ore from Zone 96 is mined at the rate of 3,500 tonnes per week using a cut and fill method. Initially, this involves mining a tunnel called a drive along the base of the ore body. Miners then drill and blast progressively upwards through the ore. Waste material (rock containing no ore) from construction of tunnels and drives is used to fill and raise the floor of the chamber or stope so that miners can access the ore above them.
Mining is done by drilling holes in the mineralised rock face, packing them with explosive, and then blasting to fracture the ore.
Underground drilling
The fractured ore is scooped up by a special type of front-end loader called a Load Haul Dump (LHD). The LHD hauls the ore to a shaft where it is hoisted in a 5 tonne skip (bucket) to a special chamber that lies 150m inside a hill above the mine. Ore is loaded into haul trucks, which transport it along a tunnel leading out of the hill to ore stockpiles to await processing in the gold plant.
Ore stockpile
