Mill Feed Quality: Where did all the Waste Come From?

Adrian Dance, Bob McCarthy
Thursday, November 26, 2015
First presented: 
Canadian Mineral Processors Conference
Mine Waste

It is not news to anyone in the industry that mill feed quality is deteriorating. It is lower grade and more complex and problematic than ever before. In addition, mass underground and bulk open pit mining methods, which enable mining at lower grades, are contributing to more and more dilution.

Geometallurgical programs are being commissioned by mining companies to ‘better understand’ the ore properties and yet, it is waste that we are processing to a greater extent.

Larger and larger concentrators are being designed and operated to take advantage of economies of scale – but should we be processing all of this material? Can we be smarter about how we ‘selectively process’ if opportunities to ‘selectively mine’ are fewer and far between?

SRK is working with clients to better understand what makes up their ore… is it all worth processing the same way? Should some be segregated and processed separately or even deferred until later? Can some, if segregated, still be considered ore?

There are a number of opportunities available to counteract the degradation of grade: AG/SAG mill pebble rejection/deferment, coarse particle beneficiation and bulk/particle sorting technologies.

The real challenge is generating hard evidence of the benefit from drillcore samples alone. Consequently, SRK is working with existing operations looking to upgrade or expand through mill feed improvement methods. This presentation will outline the available opportunities and highlight the significant economic benefits that await operations that wish to ‘delete the dilution’ and improve the quality of their mill feed.

Feature Author

Adrian Dance
With over 25 years in his field, Adrian has both industrial and consulting experience, working at operations in Australia, Canada and Peru. Recently, Adrian has established himself as an authority in comminution circuit operation and practices a proven methodology in gaining improvements from “Mine-to-Mill” optimisation projects. Adrian has spent most of his career working with existing operations to gain added efficiency. With SRK, he is now providing similar expertise to green or brownfield sites to get similar benefits very early in the mine life, in particular, the development of mill forecasting models embedded in the resource/geological block model, or geometallurgical modelling.
Plant Optimization Specialist
PhD in Mineral Processing
SRK Vancouver
Bob McCarthy

Bob McCarthy is a professional mining engineer with 30 years of experience in mine operations and engineering, asset management, technology design and implementation, and consulting. He has worked at numerous mines in western Canada, gaining experience in roles across the spectrum of mine functions and to the level of department manager.

Bob’s technical strengths lie in mine design and planning, due diligence and technical reviews, technology selection and implementation, project and change management, and mine financial analysis. Bob is particularly knowledgeable about In-Pit Crushing and Conveying (IPCC) and ore sorting, having completed multiple studies on the subject and presented at several international conferences.

Principal Mining Engineer
SRK Vancouver
SRK Worldwide