The purpose was to optimise production of 10 mm single size chippings, for which there is strong demand. Several hours of production were being lost every day due to a build-up of dust in the bins. Two areas of concern were immediately identified.

Firstly, analysis of current production and bottlenecks suggested the replacement of an unsatisfactory secondary crusher, which was reconfigured for tertiary duty. A new gyratory type secondary was installed, resulting in improved availability and capacity. More suitable reduction ratios, and the reassigning of one of the tertiary crushers as a quaternary to handle excess 14 and 20mm fractions, increased 10mm production as detailed below without a lot of extra dust production.

Secondly, all material was originally delivered from the plant final bins through a lorry load-out point. Sales were given priority, resulting in times when the high levels of dust in the bins necessitated stopping the plant. This caused the lost production hours, leading to extended working hours and variability in product grading. Modifications were made to the plant so that as bin levels increased the dust was automatically fed into a dust shed, minimising disruption.

BeforeAfter
:
Plant capacity
Before:
220t/h
After:
285t/h +
:
10mm Percentage of plant throughput
Before:
≤18
After:
36, if targeting 10mm
:
Downtime
Before:
After:
Much reduced