Crushed stone (aggregates)
Primary crushing

Primary crusher -- rocks up to 5 feet by 4 feet by 4 feet are crushed to 8 inches in diameter or less. Water spray reduces dust. This crusher is located inside the pit to reduce noise. For scale, note man visible in control room window.

 

 

 

 

Trucks with a capacity of up to 50 tons haul rock from where it is blasted and loaded by hydraulic shovels to the primary crusher. For scale note man in the window of the control room (left). 

Rocks up to 5 feet by 4 feet by 4 feet in size enter the primary crusher which reduces the size to 12 inches or smaller. Water is sprayed to reduce dust. Water is conserved and recycled in the mining and washing operations.

The primary crusher in this quarry was initially located on the surface. As the quarry was deepened, the primary crusher was relocated to the bottom of the quarry to minimize noise. 

The yellow device (left and below) is used to reduce the size of oversize rock so that it will enter the primary crusher. The yellow devise is also used to open 'rock jams' in the bin above the narrow opening to the primary crusher. A detail view of rock entering the primary crusher is shown below.

The primary crusher crushes more than 1.5 million tons of  stone per year. This is enough crushed stone to make 60 miles of road or 5,000 homes.  The primary crusher and related equipment cost several million dollars.

Process water from washing the rock here and the sizing plant, and from rainfall is gathered at the lowest point (sump) in the mine. Click here to learn more about the sump.

This view into the feed opening of the 48 inch by 60 inch jaw crusher. Rock enters the crusher from the rock box and grizzly feeder on the left. Yellow hydraulic jam-breaker is visible over feed opening.