Real-life Examples of Improvement

As-Is:  Northeast U.S. - granite operation scheduled 20 hrs per day 7 days per week averaging approximately 300 tph to supply an asphalt paving project. 

Field Evaluation:  Screen efficiency issue identified by the client was caused by excessive loading due to lack of crusher maintenance.  The cone crusher output gradation was improper due to liner wear and improper crusher setting significantly increasing screen loading; reducing screen efficiency; increasing recirculating flow to crusher; substantially reducing production rate.

Recommendation: Replace manganese liners on crusher and maintain proper closed side setting, increase feed rate to optimal. 

ResultProduction rate increased from +/- 300 tph to well over 500 tph; plus 60% increase.


As-Is:   Southern U.S. - limestone quarry averaging 1,900 tph was seeking capital for +$20 million expansion to increase capacity. 

Field Evaluation:  Field measurement and observation of recirculating conveyors indicated improper roll crusher configuration due to lack of maintenance and improper setting for current feed gradation. 

Recommendation: Increase maintenance effort on roll crusher; maintain roll crusher settings appropriate for the feed gradation; modify existing crushers and material flow to optimize utilization of existing capacity; add a medium size VSI to supplement the roll crusher capacity. 

ResultAverage production increased from 1,900 tph to over 3,000 tph with less than $1.0 million in capital.  Added capacity resulted in elimination of 2nd shift production and substantially reduced the capital expenditure.


As-Is:   Eastern U.S. - dolomite quarry with a 42x65 gyratory crusher fed from 2 separate muck piles with 9 trucks and 2 large front end loaders achieving 13,000 tons per day average PRF instead of projected 18,000 tons. 

Field Evaluation:  Field evaluation of truck and loader cycle times indicated potential capacity in excess of 20,000 tons per day.  Detailed assessment of cycle components indicated excessive lost capacity due to unregulated queuing at the primary dump location. 

Recommendation: Maintain detailed daily record of pit load & haul data, continue to monitor cycle times, initiate pre-primary surge pile to eliminate excessive lost capacity from the pit due to queuing and utilize the added surge capacity to supplement pit production as needed to optimize PRF. 

ResultAverage production PRF increased from +/- 13,000 tons per day to over 18,000 tons per day with a peak day of over 25,000 tons; resulting in over 35% increase with no capital.



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For the Aggregates and Mining Industry
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