3.3.3 Crushing

After extraction, the ore lumps are reduced in size to make them easier to transport. This operation is often carried out underground before the ore is hoisted to the surface.

The large ore lumps are first crushed with a hydraulic hammer until they are small enough to pass through a wire mesh.

		Hydraulic hammer.
	Source

The hammer can be operated by remote control from the surface using television cameras.

		Surface remote control station for an underground hydraulic hammer.
	Source

Once the large lumps have been reduced in size, a conveyor belt moves the ore to a crushing station with gyratory or jaw crushers.

		Jaw crusher at work.
	Source

Once it comes out of the crusher, the ore is generally less than 15 centimetres in size.

In certain mines, hydraulic hammers are used only to process the waste rock. The ore, much harder and more abundant than the waste rock, is broken down by the crusher.