The CMR has been involved for some years in actively providing a consulting service to industry in its areas of competency. This has proven to be a successful mechanism to ensure that it has an ongoing close association with its industrial partners by being aware of their short-term problems, and then integrating these activities into its long-term research programmes. Generally, MPTech is involved in the application of technology and research to the design, operation, and optimisation of industrial comminution and flotation circuits and in providing training to industry in advanced concentrator technology.
In the last 10 years, MPTech has executed 38 site surveys, reviewed 20 circuit designs, delivered 46 short courses to industry, and undertaken circuit optimisation studies on 19 separate occasions. The scope of the output is shown graphically below.
In the area of comminution, where historically most of the activity has occurred, interventions through site optimisation studies by MPTech have led to significant improvements in throughput, increasing the amount of final product achieved, or improved process efficiency. Mill shell liner profiles, discharge grates and pulp lifters have been redesigned to prevent or reduce slurry pooling problems.
MPTech has also undertaken several design review studies for both engineering houses and operations using the JKSimMet mineral processing simulator. The involvement by the MPTech team in site optimisation studies coupled with knowledge and experience of the software environment means that MPTech is able to offer a unique service in this field in Southern Africa.
Optimisation of a flotation circuit requires detailed information about the sub-processes occurring in a cell as well as accurate mass, water and mineral flows around the circuit. MPTech has proven experience in planning and executing flotation surveys to provide this information, including the use of the Anglo Platinum Bubble Sizer (APBS) developed by StoneThree in Somerset West for the measurement of bubble size and superficial gas velocity.
Flotation surveys conducted by MPTech have provided plants with information that has allowed them to calibrate and stabilise air input and froth depth down a flotation bank, to optimise reagent addition (dosage and point of addition) and to reconfigure stream routings leading to improved metallurgical performance.
- Comminution circuit surveys
- Detailed circuit mass balance for determination of circulating loads and identification of bottlenecks
- Grind curve testwork – mill filling, throughput, slurry/ball load, power draw
- Mill liner profile measurement (UCT liner profile gauge) and simulated charge trajectories using MillTraj
- Equipment and circuit modelling and simulation with JKSimMet
- Flotation circuit surveys
- Pulp phase hydrodynamics – superficial gas velocity, bubble size and gas holdup
- Froth phase stability and mobility
- Robust material balance techniques even for sparse minerals
- Floatability component analysis for simulation using JKSimFloat
- Mobile sample processing trailer – a portable laboratory with all the equipment required for collecting samples and conducting full sizing analyses on site
- Ore hardness characterisation
- Particle size and shape characterisation
- Particle mineralogy / composition
- Slurry rheology
- Depressant characterisation
- Bench scale batch flotation testing for reagent screening
- Controlled pulp chemistry grinding (Eh, pH, DO, grinding media) coupled with flotation response
- Stirred milling signature plots with flotation response
- JKSimMet – comminution circuit mass balancing, optimisation and design
- JKSimFloat – flotation circuit mass balancing, optimisation and design
- MillTraj – ball and rock charge trajectories in mills
Courses of up to one week’s duration allow sites to improve their internal research and development strategies and initiatives, to take advantage of the current state-of-the-art in comminution, classification and flotation optimisation.
The current training toolbox includes:
- Advanced Concentrator Technology (ACT) short courses
- Comminution and classification theory
- Principles of flotation
- Sampling and surveying
- Mass balancing and data reconciliation
- Using the Anglo Platinum Bubble Sizer (APBS)
- Software training courses
- Mineral processing plant simulation, optimisation and design using JKSimMet™ Mineral Processing Simulator
- Flotation circuit optimisation using JKSimFloatTM
- Mass balancing using matrices
- Process Mineralogy
MPTech has responded to global and local demand for high calibre technical staff to service the expanding industry and has undertaken to provide training to graduates in industry. For AngloAmerican Platinum this has taken the form of a structured, two-year training programme (the AGDP) at a level equivalent to a Post Graduate Diploma in Engineering. Key to the effectiveness of the AGDP is the methodology employed whereby the courses are delivered at site. In this way, cutting edge technologies are brought to bear on challenging real world problems. The first cohort enrolled in 2004 and the programme has been evolving and improving for over a decade in response to the challenges of the global recession, skills retention, and the changing operational needs of the company.
From the beginning, the programme was structured in a modular fashion to include a basic technical “toolbox” including statistics, the scientific method and sampling protocols, while the mineral processing content comprised advanced learning in comminution, classification and flotation (later extended to include hydrometallurgy). Technical communication – both written and verbal – was included from the start. The programme was focussed very strongly on site work, with a major integrated site campaign conducted and analysed by each cohort.
The benefits of the programme for AngloAmerican Platinum have been tangible, and include improving the survey sampling protocols, the introduction of effective mass pull control, reduced steel ball consumption and dramatically improved mineral recovery. In addition, the number of graduates leaving the company has steadily decreased and over 60 % of the more than 200 graduates employed by AngloAmerican Platinum since the inception of the AGDP remain in the company today.