Pyrometallurgy
is an essential
and beautiful part
of sustaining society.”

ABOUT

Company Profile

OUR STORY

Ex Mente is a process engineering consulting and systems company, focused on pyrometallurgy. We guide our clients by means of expert consulting and training services as well as the deployment of software systems to improve their operations. The company was founded in 2001 and is based in Pretoria, South Africa.

OUR BRAND

Our brand was developed
on the concept of mutualism.

Our logo illustrates the honeyguide, which exists in a mutually beneficial relationship with humans, where both parties guide each other to success. The honeyguide leads humans to beehives for honey and reciprocally, humans clear the hives of bees allowing the honeyguide to eat beeswax. This relationship of mutualism symbolises how we guide our clients to solutions which allow them to unlock maximum value from their resources.

OUR VISION

Our vision is to develop a thriving pyrometallurgical industry by unlocking value with our clients, through deeper insight into their materials, processes and equipment.  We strive to forge meaningful long-term partnerships with our clients.

OUR FOCUS

We are fascinated by pyrometallurgy and believe it has a key role to play in the advancement of society. We have developed a unique set of skills and tools to assist our clients in improving their pyrometallurgical operations.

OUR TEAM

OUR TEAM

DR Johan Zietsman

CEO

Marius Schoeman

Chairman of the Board

Dr Willem van Niekerk

Non-executive Board Member

Dr Alfred Bogaers

PRINCIPAL MECHANICAL ENGINEER

Rita de Villiers

Administrative Officer

Tumelo Makgoale

PROCESS ENGINEER

Edna Monyepao

OFFICE ASSISTANT

Dr Willem Roos

SENIOR MECHANICAL ENGINEER

Dr Jaco Swanepoel

Senior Process Engineer

Rudie Theron

Manager Projects

Stefan van der Merwe

Software Engineer

Dr Bernard van Vuuren

Manager Team Empowerment

Heine Weitz

MANAGING DIRECTOR - EX MENTE EUROPE

Marinda Zietsman

General Manager

PROCESS ENGINEERING TEAM

FROM LEFT TO RIGHT:
Dr Johan Zietsman, Tumelo Makgoale, Dr Jaco Swanepoel,
Heine Weitz

MULTIPHYSICS TEAM

FROM LEFT TO RIGHT:
Dr Johan Zietsman, Dr Alfred Bogaers, Dr Willem Roos

SOFTWARE ENGINEERING TEAM

FROM LEFT TO RIGHT:
Dr Johan Zietsman, Stefan van der Merwe

OPERATIONS TEAM

FROM LEFT TO RIGHT:
Dr Johan Zietsman, Rita de Villiers, Edna Monyepao,
Rudie Theron, Dr Bernard van Vuuren, Marinda Zietsman

EX MENTE EUROPE

FROM LEFT TO RIGHT:
Dr Johan Zietsman, Heine Weitz

DR Johan Zietsman

CEO

Johan is an experienced metallurgical engineer, skilled in pyrometallurgy, thermochemistry, computational modelling and consulting in a wide range of commodities such as iron and steel, high-titania slag, ferrochrome, ferromanganese and platinum group metals. Through his software engineering skills and experience, he contributes to system design and implementation solutions for clients.

Johan leads the Ex Mente team and supervises a number of postgraduate students at the University of Pretoria.

Marius Schoeman

Chairman of the Board

Marius is a qualified Chartered Accountant (SA) and Chartered Director CD(SA)® with more than 35 years’ experience across the Audit Profession, Oil & Gas, ICT and Financial Services sectors.

He has served in various senior level executive roles, among others, a Chief Audit Executive, Group Risk Officer, Ethics Officer as well as Group CFO of a JSE listed entity.
He is founder and CEO of Ujasiri Consulting and advises a number of corporate clients on governance, risk and compliance (GRC), assurance and contracted services as a Compliance Officer, Information Officer and Head of Legal and Business Support. With his wealth of experience, Marius is an invaluable member of the Ex Mente board.

Dr Willem van Niekerk

Non-executive Board Member

Willem is an experienced senior executive with nearly 40 years of experience in the minerals, mining and chemical industries. He holds a PhD from the University of Pretoria, a BCom from UNISA, an MBA from Henley Management College (UK) and has published/presented nearly 30 papers globally.

Willem’s skills range from innovative technological developments to leading chemical and mining operations globally. He has served on numerous boards and has extensive corporate governance experience, which he now offers to Ex Mente as a board member of the company. Aside from his involvement at Ex Mente, Willem is an independent consultant since retiring from Tronox (NYSE listed) in 2021.

Dr Alfred Bogaers

PRINCIPAL MECHANICAL ENGINEER

Alfred is a mechanical engineer specialising in computational mechanics and numerical methods. His focus is primarily on Multiphysics modelling of problems related to conjugate heat transfer and fluid-structure interactions. Throughout his career, he has received various awards including best PhD (Faculty of Engineering and the Built Environment, UCT), best Masters (Department of Mechanical and Aeronautical Engineering, UP), best paper awards at both local and international conferences as well as a number of emerging researcher awards.
Rita de Villiers BG

Rita de Villiers

Administrative Officer

Rita is dedicated to supporting the team and the organisation to function more effectively.
She is responsible for supplier relations and administration, organising conferences, and keeping the office running on a day-to-day basis.

Tumelo Makgoale

PROCESS ENGINEER

Tumelo is a metallurgical engineer, who recently completed his master’s degree in the field of Pyrometallurgy. He helps clients to improve their processes with tools such as thermochemistry and process models.

Edna Monyepao

OFFICE ASSISTANT

Edna is the Ex Mente team’s administration assistant. She is a friendly, helpful person and her main responsibility is to support and care for the team in any way possible.

Dr Willem Roos

SENIOR MECHANICAL ENGINEER

Willem is a mechanical engineer with a newfound interest in thermochemistry and its inclusion into multiphysics and process models.
He is part of the Multiphysics team at Ex Mente where he contributes to the solvers and models that are developed to investigate large, complex, high-temperature systems.
Through his PhD research at the University of Pretoria, he developed, implemented, and tested an acceleration algorithm that would allow a large number of multi-component, multi-phase, high-temperature thermochemical equilibrium calculations to be included into multiphysics and process models more efficiently.
This will allow our multiphysics and process models to provide additional insight into industrial processes and equipment.

Dr Jaco Swanepoel

SENIOR PROCESS ENGINEER

Jaco is a Chemical Engineer with twelve years of experience in projects that range from reactive metals handling, reactive metal powder production in molten salt slurry reactors, extractive metallurgy to microwave-assisted gas-solid materials processing.
Jaco contributed to three process patents and obtained a PhD degree in Chemical Engineering. Jaco also completed the KTP Management and Leadership Study Program at Ashorne Hill Management College, England.

Rudie Theron

Manager Projects

Rudie is an experienced electrical engineer (heavy current) and has also been involved as an engineering manager and commissioning engineer on various previous projects. As a project manager at Ex Mente, he is responsible for integrated planning and scheduling as well as finances and execution of projects across the two disciplines that Ex Mente has on offer.

Stefan van der Merwe

SOFTWARE ENGINEER

Stefan’s greatest passion is to enable people. By combining his greatest passion with his love for technology, he finds joy in making computing infrastructure accessible to the non-technical, and developing software that uncomplicates tasks. As a software engineer with qualifications in electronic engineering and bioengineering, Stefan is responsible for software development, enabling the team and clients to advance through insight.

Bernard van Vuuren BG

Dr Bernard van Vuuren

Manager Team Empowerment

Bernard joined Ex Mente to empower the team members and to support the overall wellness of the team. He is further responsible for creating an environment in which the team can learn, grow and perform. Bernard is a lifelong scholar of human behaviour, leadership, team development and performance. He is a strong believer that any organisation’s greatest asset is its people.

Heine Weitz

MANAGING DIRECTOR - EX MENTE EUROPE

As a metallurgical engineer by training, Heine has invested the majority of his career in the pyrometallurgical industry, serving in different roles in operations, design and consulting companies. He has had the privilege of working with numerous commodities across the globe including Africa, North America, Europe, the Middle East and Asia.

His professional interests include operational and process analysis, thermochemistry, computational modelling and process development and improvement.

Heine leads Ex Mente Europe as managing director. In this role he is responsible for growing the team in Europe and to ensure that we make a meaningful contribution in the region’s pyrometallurgical industry.

Marinda Zietsman

General Manager

Marinda has been with Ex Mente for the past 20 years, supporting operations management to create an environment in which the Ex Mente team can do great things. Her main areas of responsibility are finance, human resources, legal, business management and software sales.