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.
Result: Production 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.
Result: Average
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.
Result: Average 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.
