Quarry Fines Minimization

Case Study: Limestone Quarry

Operation: Limestone quarry, Leicestershire

1.       Geology: Mill dale Limestone Formation & Mud mound Reef, Cloud Hill Duotone Formation, Carboniferous

2.       Products : Road stone, agricultural lime, crushed rock aggregate

3.       Process plant: A two stage crushing circuit with Jaw and Impact crushers.

4.       Process optimization: A process audit was carried out to determine the mass balance’ of the existing circuit. The aim was to reduce fines production and maximize the amount of concrete aggregate produced.

Limestone Quarry Process change

1.       Current operation: Two stage crushing circuit using a primary Jaw crusher and a secondary Horizontal Shaft Impact (HSI) crusher (closed circuit).

2.       Process Change: The HSI crusher was replaced by a Cone crusher in the secondary crushing stage

3.       Result: The amount of fines was reduced whilst the production of 4/20 concrete aggregate increased.

original process circuit

Case study: Conclusions

1.       Process change: Replacement of an HSI crusher with a Cone crusher

2.       Products: The amount of concrete aggregate produced increased from 47 to 71tph; this represents a 50% increase in production

3.       Fines: The amount of fines produced overall decreased from 67 to 44tph; this represents a 34% reduction in fines (the reduction in fines is directly equivalent to the increase in concrete aggregate production, 23 and 24tph respectively)