JOHANNESBURG (miningweekly.com) – South Africa’s national minerals research organisation Mintek has highlighted the value of conducting bottleneck-exposing comminution circuit surveys at platinum group metals (PGM) processing operations and made it clear that it is at-the-ready to answer all questions relating to peak performance and plant optimisation.

The aim of Mintek’s comminution circuit surveys is to arrive at advantageous process performance by unlocking hidden opportunities of process improvement in PGM processing plants. (Also watch attached Creamer Media video.)

“We'd really like to get some invites to come and conduct surveys,” Mintek minerals processing division senior engineer Dr Sandile Nkwanyana enthused during Mintek’s PGM Day covered by Mining Weekly.

Nkwanyana was one of a dozen Mintek managers, engineers and scientists who presented in the auditorium of this 92-year-old State-owned research organisation, which is situated at 200 Malibongwe Drive in Randburg.

Displayed were comminution circuits within the PGM processing space. The first was a mill float two circuit, showing the primary mill and the secondary ball mill. The second comminution circuit was a circuit with a semi autogenous grinding (SAG) mill and the third an autogenous grinding (AG) mill followed by low-grade ball mill circuit.

“What I want to stress is that the primary mill, which is either the run-of-mine ball mill, SAG mill, or AG mill, is usually the bottleneck when you're trying to increase throughput in your circuits,” Nkwanyana pointed out.

Also learnt over the years is that throughput does not respond linearly to parameter changes.

Having a signature grind curve was described as being important.

Mintek conducts full surveys around the circuit for the purpose of generating a grind curve to provide insight into where peak performance resides.

What is shown is the load level that gives the peak in power and going above that load is not necessarily beneficial for the mill.

Following the conducting of surveys, Mintek favours mill modelling to gain insight into other performance improvement opportunities around the circuit and to ensure mass balance.

The modelling exercise involves the use of in-house coded models as well as the JK Cement modelling platform.