case study – tarkwa crusher survey - orway mineral...

ORWAY MINERAL CONSULTANTS (WA) PTY LTD Level 4, 1 Adelaide Terrace, East Perth WA 6004, A.B.N 40 093 277 126

Tel: +61 8 6210 5601 Fax: +61 8 6210 5555 Email: omc@orway.com.au Web: www.orway.com.au

Scope of Work

OMC’s scope of work was to optimise the existing North Heap Leach crusher plant at Tarkwa and determine whether a throughput of ≈1300 tph would be possible (8 Mtpa @ 70% availability) on future ore. As the ore hardness increases, the porosity decreases and as such a finer crushed product size is required to achieve acceptable heap leach recoveries.

Flowsheet

The circuit consisted of an open circuit gyratory crusher (50/65 Metso), open circuit secondary crushers (2 x S6000 Sandvik) and closed circuit tertiary crushers (3 x H4000 and 3 x C660 Sandvik).

Notable Feature

High throughput had been possible over the years on soft ores but throughput was severely restricted when processing the more competent ore types.

Outcome

Two crushing circuit surveys were taken on soft and competent ore respectively. Models for the Tarkwa crushing circuit were generated using both PlantDesigner® and JK SimMet. Recommendations to optimize crusher CSS and screen apertures were provided based on the modelling along with suggestions to maintain the choke feed conditions on the crushers.

Case Study – Tarkwa Crusher Survey

Kambalda Mill Survey

Project Category: Optimisation

Client: Gold Fields Ghana

Location: Ghana, West Africa

Capacity: 8.0 Mtpa

Commodity: Gold Tarkwa NHL Crushers