Project details

Approach: Develop analytical and modelling techniques to measure and analyse the liberation characteristics of rocks at coarse particle sizes.

The objective of this project is to predict mass and value flows to accept and reject streams. The focus of the research is on grade engineering (1) to measure and model gangue liberation and yield curves together with the preferential deportment of grade to specific size fractions during rock breakage (2).

The project provides a basis on which low value waste can be diverted out of the mining value chain prior to expensive and environmentally deleterious comminution and processing operations. This involves rejecting material at relatively coarse particle sizes (typically 10 mm to 200 mm in size) prior to fine crushing and SAG milling. Very little is known about the inherent particle grade distributions that are present in these coarse particle size ranges. The approach is to model gangue liberation and yield curves together with preferential grade deportment to predict mass and value flows.

Two major contributors to this challenge are the amount of material that must be sampled and analysed at these coarse particle sizes (as determined by Gy’s formulae (3,4)), and the general lack of analytical and modelling techniques that can measure and analyse the liberation characteristics of rocks at these coarse particle sizes. By contrast, fine particle liberation measurements in grinding mills and flotation plants have been routinely captured for over three decades using process mineralogy tools such as QEMSCAN (Quantitative Evaluation of Materials by Scanning Electron Microscopy) and MLA (Mineral Liberation Analyser).

Project image courtesy of Scantech – Particle size distribution using SizeScan.


Nazym Baizhiyen


University of Adelaide

Key Contacts

Principal Supervisor:
Professor Peter Dowd


Ph: +61 08 8313 4543

Associate Professor Chaoshui Xu
Dr Gregory Wilkie
Professor David Lewis

Supervisor Profile


(1) CRC ORE.
(2) Walters, S.G. (2016) Driving productivity by increasing feed quality through application of innovative grade engineering® technologies.
(3) Pitard, F.F. (2019) Pierre Gy’s Sampling Theory and Sampling Practice. Third edition, CRC Press.
(4) Minnitt, R.C.A. (2017) A version of Gy’s equation for gold- bearing ores, Journal of the Southern African Institute of Mining and Metallurgy, 117; 119-132.

Industry Partners