A quarry is a big man-made hole in the ground from where minerals or rock are taken out. Quarries are made when big deposits of commercially helpful minerals or rock are found close to the Earth's surface. Quarrying is a type of mining and is also called as open pit mining or strip mining. When minerals are found profound beneath the surface, a deep mine has to be dug to dig out them. Quarries are normally dug deeper and bigger; awaiting the mineral resource is worn out. When they are no longer used, quarries are frequently utilized as landfill sites for the disposal of waste.
Quarries in level areas frequently have particular engineering problems for drainage. The Coquina Quarry is excavated to more than 60 feet (18 m) beneath sea level. To lessen surface leakage, a moat lined with clay was constructed round the complete quarry. Ground water that leaks into the pit is pumped up into the moat. Many quarries fill with water after desertion and turn into lakes. Further quarries are made into landfills.
A further problem is the pollution of the road from trucks when they are leaving the quarries. To control and eliminate the pollution of public roads wheel washing systems are becoming more common.
Quarry management varies from case to case the optimal proceeding method. The main quarrying methods are drilling and diamond wire cutting. In many cases also chain cutting is used but only for marble or travertine.
Generally speaking, quarry equipment includes the following machinery: pneumatic steel drillers (for vertical, horizontal or inclined drilling, manual or mounted on special devices), mostly diameter 34 mm, pneumatic down-the-hole hammer drillers (for making vertical holes for introducing the diamond wire), mostly in diameter 85-90 mm, diamond wire machines (for large primary cuts), smaller diamond wire machines (for secondary cuts), etc.
Different quarrying machines have different functions which have to be evaluated according to the following factors:
1. Type of rocks (hard, soft, abrasive, etc.)
2. Specific configuration of the quarry
3. Quarry yield or recovery (normally between 25 and 50%)
4. Value of the material
5. Requested production speed
6. Specific tool costs
7. Machine depreciation
8. Labor cost