There are two main ways of making natural aggregates: by crushing hard rock or by processing sand and gravel. These methods are different and are explained below.
Hard Rock Quarrying Equipment
Before hard rock can be removed, the overlaying topsoil and 'overburden' (weak or weathered rock) must first be put to one side to expose the fresh, hard rock underneath. This first stage of quarrying is called 'stripping'.
Related: gravel production line
The fresh rock can then be quarried in a 'step' pattern that we call benching. Over many years a hard rock quarry, with its series of benches, can become very deep - sometimes hundreds of metres deep. A busy quarry can remove over 1 million tonnes of rock per year.
To make aggregates from hard rock we must break the rock up into smaller pieces. In the early days of European settlement of Australia the rock was broken by hand - men (often convicts) used hammers to break the rock into blocks and also into chunks called 'spalls'. It was incredibly hard work. These days we use technology to make the job very much easier and very much quicker.
To break the rock (small rock crusher), explosives are used to blast a certain amount of rock in a careful and controlled manner. The explosives are placed in holes that have been carefully and accurately drilled down into the bench. When everyone is safely away from the blast area, the explosives are detonated (or exploded) by a person known as a 'shotfirer'. Because most quarries have neighbours, the blasts are designed so that noise and vibration are minimised.
It can take several days to drill the rock and a day to place the explosives. But the blast is over in just a few seconds! aggregate production line
After the rock has been broken by blasting, it can be loaded by excavators or face shovels into dump trucks. It is then hauled by dump truck to a crushing plant. Occasionally a conveyor is used to take the broken rock to the crusher.
At the quarrying plant crushing plant, the rock is broken and shaped into smaller and smaller pieces by crushing machines called rock crushers. Usually, the rock is sorted into different sizes by passing it over special screens. The screens are like sieves that let smaller rocks through but not the larger ones. The finished rock products are known as aggregates.
Tags: Gravel-producti On-lineaggrega Te-crushing-pla Nt
