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TEACHER'S GUIDE
HOW A STONE QUARRY WORKS

1. STRIPPING
Topsoil is removed and saved as required for reclamation. It is retained in berms for safety, noise, and aesthetic purposes. Subsoils are removed to expose the rock surface.

2. DRILLING
The exposed rock is drilled in preparation for blasting.

3. BLASTING
The holes'are charged with an explosive and detonated- The material produced which is less than 40 inches in diameter is ready to be transported to the primary crusher- Oversize material must first be broken into a workable size with a hydraulic hammer.

4. CRUSHING
Stone fed into the primary crusher is reduced to a variety of sizes, the maximum being twelve inches. The crushed material is transported by conveyor to a screening tower.

5. SCREENING
In the screening tower material passes over a series of screens to separate out the various sizes and ranges of sizes. Each successive screen has larger openings which allows larger and larger sizes to be sifted out. Stones too large to pass through the largest openings are re-routed to a crusher and then over the screens again until they find their place.

6 . STOCKPILES
The different grades of stone are transported from beneath the respective screens by conveyors onto stockpiles. Here they are.stored until they are loaded onto trucks to be delivered to customers.

In the actual operation at Rohrer's Quarry five crushers are operated in succession with three separate screening towers. The process shown in the diagram is a simplification of an actual quarry, but accurately pictures each of the steps used in a typical operation.

The limestone crushed at Rohrer's Quarry is used for building stone, landscaping, road and parking lot construction erosion control, concrete, asphalt, septic systems, agricultural lime, fertilizer filler, foundry use), filler in golf courses, pollution control in coal burning generators. and skid control on ice.

© 1999 Randy E. Newcomer

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