Catoca diamond mine capacity expansion project in Angola (HPGR is used to crush AG Mill pebbles )
Customer: Catoca Diamond Mine Angola (join venture project)
Location: Angola (Africa)
Ore Category: Diamond
Scope of Work: Supply HPGR and System Solutions for expansion project
  • The ore in Catoca diamond mine is typical Kimberlite, the original design used 3 Polysius’s AG mills (7.2m X 3.2m ).  
  • Before the expansion, a considerable amount of gneiss is often mixed in during the production, and its hardness is f=12-22. The accumulation of gneiss in autogenous grinding circuit often affects the ability of the AG mill. The designed process capacity of a single AG mill is 400t/h, and its process capacity for pebbles is 200t/h. When the gneiss reaches 30% in newly fed ore, the new ore feed in the autogenous grinding circuit will be reduced to below 300t/h. When the continuous circulation of gneisses accumulate in the circuit of the autogenous mill, that will cause the new ore feed in the autogenous grinding circuit to be stopped, and the hard rocks must be discharged through the pass open circuit.
  • After the upgrade with HPGR (open circuit) added, and when the proportion of gneiss is less than 30%, as the feed materials have been processed by HPGR prior to AG mill, hence the new ore feed capacity of a single AG mill has increased from 400t/h to 500t/h with a consistent production, improved by 25%. When the proportion of gneiss is great than 30%, the new ore-feed capacity of a single AG mill can still be stabilized at 450t/h, compared with the throughput without HPGR before the expansion, the new ore-feed capacity increased from 300t/h to 450t/h, an 50% improved.

    Note: Catoca is the fourth-largest open pit mine in the world and the largest company in the diamond sub-sector in Angola.