Crusher Closed Side Setting (CSS) Measurement using the ‘C-Gap’ Device

Sponsored by: Mintap Services Pty Ltd

Focused on:

  • Css Measurement
  • Product Optimisation

Date: 9 September


Time: 3PM London/10AM New York

How can a safer, quicker and more accurate CSS measurement technique improve Mine to Mill Optimisation and Crushing Plant Performance

Mine to Mill or Mine to Product optimisation is crucial in ensuring maximum economic return on a Project. Much emphasis is placed upon blast fragmentation at the mine, to crusher/mill modelling and selection, however little thought is put into one of the major performance drivers at the Crusher; the Closed Side Setting (CSS). The Crusher Operator on a daily basis can control two drivers, being crusher throughput and CSS. Throughput is easily and accurately determined, however to date, the CSS has only been measured by inaccurate, unsafe, subjective and inefficient methods. This lack of confidence in the measurement and the time and personnel required to obtain it typically leads to the CSS being measured infrequently. This can lead to a breakdown in the entire Mine to Mill optimisation chain as crusher performance and/or crusher product size is severely impacted thus impacting the highest capital item onsite being the downstream Comminution circuit.

The focus on CSS at a Production and Site Management level has suffered by the lack of an accurate, quick and safe measurement technique hence has received little or no attention. Just like the measurement of pH in a Flotation circuit or mill power, if you can’t measure it, you can’t manage it, and if you can’t manage it, you can’t improve it. For the Crusher, this is just as relevant.

Like most things, if it’s easy and the results are accurate, the task will most likely be adopted and accepted. To date, the measurement of the CSS has been far from this hence the introduction of the C-Gap in 2012 has been to some something that they’ve been looking for, and for others, something they didn’t know they needed.

The C-Gap has proved itself over the last eight years in being a daily optimisation tool for Operators and Maintenance staff. It has been sold to over 80 Mining and Quarrying projects in 20 countries with its use becoming a crucial tool in the day to day operation of the Crusher and forming a part of their preventative maintenance and liner changeout routine.

Presented by

Brant Tapley,

Director and Metallurgist

Brant graduated as a Metallurgical Engineer from the Western Australian School of Mines (WASM) in 2003 before working at a number of gold, base metal and magnetite operations across Australia, United States, Norway and Russia. Brant is a director of a metallurgical consulting firm called JT Metallurgical Services and of a niche Plant Operations/Maintenance firm called Coil Group specialising in the management of gold processing plants.

Whilst being in Operations, Brant encountered the same issues when it came to measuring the CSS - it took too long to do it safely and it wasn’t accurate. The development of the C-Gap stemmed from these common complaints.

Key Learning Objectives

  • Importance of measuring the CSS
  • The pitfalls of traditional CSS techniques
  • How the C-Gap works
  • Benefits of using the C-Gap and where is it in Operation today


  • Metallurgists
  • Process Managers
  • Plant Superintendents
  • Safety Advisors/Managers
  • Fixed Plant Maintenance
  • Maintenance and Engineering Managers