OUR TRACK RECORD
GOLD FIELDS - SITE IMPROVEMENT PROJECTS
The Details
TIMEFRAME: 2019 - 2025
CLIENT: Gold Fields Pty Ltd
LOCATION: Western Australia
COMMODITY: Gold
SERVICES: Subject Matter Experts
AGNEW
Crushing plant performance assessment
GRUYERE
Pebble crushing, gravity circuit and chute assessments
AGNEW
Bogged tails line assessment
Project Background
Gold Fields is a global top 10 gold producer and they operate the Gruyere (350koz/a) and Agnew (250koz/a) mines in Western Australia.
Gruyere Site Projects
Gold Fields commissioned their 7.5Mt/a Gruyere processing plant in 2019. As the percentage of hard and abrasive fresh ore in the feed ramped up in the first 2 years, a number of plant improvements were required to maintain plant utilisation and throughput. In 2021, Gold Fields engaged Chemech to assess a number of plant improvement options, before acting as Owner’s Representatives for their re-design.
As the mine moved into fresh ore, Gruyere's two pebble crushers suffered very low availability and poor operational performance. There were a number of design related issues including poor layout for maintenance activities, unsuitable equipment selection, inadequate instrumentation and poor control. Analysis of the issues by Chemech was supported by their comprehensive database of relevant pebble crushing benchmark data. They were able to recommend options for immediate improvement including chute re-design to significantly improve availability, and instrumentation/control upgrades to improve performance. They also recommended replacement with a larger and more robust crusher, which Goldfields subsequently chose to proceed with.
Chemech also assisted Gold Fields with options to upgrade the gravity circuit, and re-design of a number of chutes causing low plant availability. Chemech were engaged as Owner's Representatives during the re-design process, reviewing and approving design modifications.
Agnew Site Projects
A “temporary” contract crushing plant was installed at Agnew in 1996 to allow a new plant to be built. The new plant was never built, and Gold Fields purchased the contractor’s plant in 2016. The plants poor design, old equipment and other legacy issues however resulted high costs, poor reliability and OH&S risks. In 2019, Gold Fields engaged Chemech to conduct an independent review of the crushing plant performance and to recommend upgrade or replacement options. Chemech provided both short and long-term options for improving performance as well as options for replacing the plant. In 2022, Gold Fields successfully replaced it with a new crushing plant.
In 2024, Agnew suffered a significant downtime event when their 16km long tails line bogged during operation. Gold Fields subsequently engaged Chemech to conduct an independent review of the tails pumping system due to their significant experience designing large and complex tailings systems such as Boddington. The long, downhill, and relatively small diameter pipeline presented a relatively complex design challenge and required a very narrow operating range. Chemech’s review highlighted a number of design deficiencies with a recent upgrade that led to the event, and they made a number of short and long-term recommendations to improve operation and reduce the risk of future downtime events.
I've been working with Chemech for over 20 years, consistently relying on their expertise for support with a wide range of site issues and projects, or sometimes just bouncing ideas off them. Their operational, metallurgical and plant design knowledge is exceptional, and there hasn’t been anything they haven’t been able to assist with. Chemech responds immediately and communicates complex problems in a way that’s clear and actionable. They’re not just technical experts—they’re practical, approachable, and genuinely invested in helping site troubleshoot, optimise, and debottleneck the plant.
- Matt McKee-Duff, ex Manager - Processing, Gold Fields Agnew Operations