This document discusses the production of concrete aggregates, including that crushed stone, sand, and gravel are the most abundant natural resources and are fundamental building blocks of modern society. It provides details on aggregate production quantities in the US, the types and locations of aggregate sources, and the processes used to extract, crush, screen, wash, and stockpile aggregates to produce materials for use in concrete. The production of aggregates is a large industry that utilizes quarrying, crushing, screening, washing, and stockpiling to extract and process billions of tons of crushed stone, sand and gravel resources annually in the US and worldwide.

1. CON 121
Concrete Aggregate
Session 2
Concrete Aggregates Production 1

2. Crushed Stone, Sand, and Gravel
 Most Abundant Natural Resource
 Used From Earliest Time of Civilization
 Fundamental Building Block-Modern Society

3. Aggregate Production-USGS (2006)
 2.9 Billion Metric tons
 9.8 tons/person
 Types of Aggregates
 Crushed Stone- Higher volume
 Sand/Gravel

4. Aggregate Locations

5. Aggregate Trends
 Crushed Stone
 Smaller Footprint
 Limestone Reserves–100’s Feet Thick
 Sand/ Gravel
 Surficial Alluvial Deposits
 Reserves-50 Feet Deep

6. Limestone Quarries
Quarry face may vary depending on limestone deposit.

7. Sand and Gravel Pits
Sand dredged from lake and conveyed and moved with front-end loader

8. Land Use Concerns
 Mining Access
 Farmland-Agricultural
 Construction Sites
 Populated Areas
 Permitting
 Environmental noise
 Dust Issues

9. Aggregate Reserve Types
 Class A – Proven
 Class B – Probable
 Class C – Indicated
 Class D – Inferred

10. Production States (2006)
 Leading Crush Stone  Leading Sand/Gravel
 Pennsylvania  California
 Texas  Texas
 Florida  Michigan
 Illinois  Arizona
 Georgia  Ohio

11. Active Production (2006)
 Operations  Average Output
 5600 Crushed stone  Crushed Stone Quarry
quarries 175,000 tons
 7000 Sand/Gravel  Sand/Gravel Quarry
quarries 100,000 tons

12. Types of Primary Crushers
 Compression
 Single Toggle Jaw Crusher
 Double Toggle Jaw Crusher
 Gyratory Crusher
 Impact
 Single roll/Hammer Mill
 Double roll/Hammer Mills

13. Types of Primary Crushers

14. Aggregate Processing
 Basic Processing
 Crushing
 Screening
 Washing
 Benefication
 Heavy media separation
 Jigging
 Rising-current classification
 Crushing

15. Crushing/Washing
 Screens used to Separate
 Smaller Screens
 Larger Screens
 Aggregate Crushed & Screened Several Times
 Aggregate Stockpiled According to Size

16. Screening and Storing

17. Heavy Media Separation
 Heavy Liquid – Relative Density (SpG)
 Heavier Particles Sink
 Lighter Particles Float

18. Jigging Separation
 Particles Separated by Density Differences
 Upward Pulsations of Water Move Lighter
Particles on Top are Removed

19. Rising-Current Classification
 Particles with Large Differences in Density
Separate
 Lighter Particles Float

20. Handling and Storing
 Minimize Separation
 Minimize Degradation
 Minimize Contamination

21. Aggregate Stockpiles
 Truck-Dump Method
 Clamshelled Bucket
Method
 Conveyor Belt

22. Concrete Aggregates Production
Please return to Blackboard and watch the
following videos:
 Video 1: Storing / Handling
 Video 2: Particle Shape / Surface Texture