oresorting

Oresorting is a broad term used in mineral processing to describe the various techniques employed to separate valuable minerals from waste rock after mining. The primary goal of oresorting is to increase the concentration of the desired commodity, thereby reducing the amount of material that needs to be processed further and lowering overall operational costs. This pre-concentration step can significantly improve the economic viability of a mining operation, especially for low-grade or complex ore bodies.

There are numerous oresorting technologies available, each suited to different types of minerals and ore characteristics. These technologies often rely on physical properties that differ between the valuable minerals and the gangue (waste material). Common sorting principles include density, color, magnetic susceptibility, conductivity, and X-ray fluorescence. For example, density-based sorting uses differences in specific gravity to separate materials, while sensor-based sorting utilizes optical or electromagnetic sensors to identify and divert specific particles.

The oresorting process typically begins with crushing and screening the mined ore to a specific size range. The sized material is then fed into the sorting equipment. Sensors detect the properties of individual particles, and a system of air jets, mechanical arms, or other actuators separates the valuable particles from the waste. The sorted material can then be sent for further comminution and processing, such as grinding and flotation, or directly to smelting or refining depending on the commodity.

Oresorting has several advantages. It can reduce energy consumption and water usage in downstream processing by handling less material. It can also extend the life of a mine by making lower-grade resources economically viable. However, the effectiveness of oresorting depends heavily on the ore's characteristics and the chosen technology, and capital investment for sorters can be substantial.