GOLD PROJECT (WA 1)

Project Category: Optimisation
Client:
Location: Western Australia
Capacity: 4.0 Mtpa
Commodity: Gold

Scope of Work

Orway’s scope of work was to assist with optimisation of the crushing and grinding circuit to ensure maximum throughput was being achieved through the existing plant.

Flowsheet

The comminution circuit consists of a primary jaw crusher (C160, 220kW) followed by closed circuit secondary crushing through a secondary cone crusher (HP500, 355kW) operating in closed circuit with a 2.4 x 7.3m inclined double deck screen.  The grinding circuit comprises of a primary grate discharge ball mill (ø5.50 x 9.30m EGL, 4,500kW) operating in closed circuit with a pebble crusher (CH430, 132kW) and a secondary overflow ball mill (ø5.29 x 8.70m EGL, 4,500kW) operating in closed circuit with a cluster of Cavex CVX250 cyclones.

Notable Feature

Both the crushing and grinding circuits were operating close to maximum capacity, however the pebble crusher was observed to be underutilised.  Changes to the primary mill grates to relieve the primary mill and increase pebble crusher utilisation were proposed. The changes also helped to relieve the upstream crushing circuit by allowing a coarser product to be fed to the primary mill.

Outcome

The proposed changes were predicted to increase the grinding circuit throughput by around 10% with the crushing circuit capacity matched by increasing the bottom deck screen apertures. A small increase in final grind size was predicted.