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

ABOUT

Company Profile

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 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 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.

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

BACK ROW: Dr Johan Heyns, Willem Roos, Dr Johan Zietsman, Marius Schoeman, Dr Alfred Bogaers, Nico van Hoepen.
MIDDLE ROW: Charlotte Hollenbach, Marinda Zietsman
SEATED: Tumelo Makgoale, Nicole Sweeten, Dr Johan Steyn, Heine Weitz, Edna Monyepao, Rudie Theron

DR Johan Zietsman

CEO

Marius Schoeman

Chairman of the Board

Dr Willem van Niekerk

Non-executive Board Member

Dr Alfred Bogaers

PRINCIPAL MECHANICAL ENGINEER

Dr Johan Heyns

LEAD MECHANICAL ENGINEER

Charlotte Hollenbach

Manager Projects

Tumelo Makgoale

INTERN PROCESS ENGINEER

Edna Monyepao

OFFICE ASSISTANT

Willem Roos

SENIOR MECHANICAL ENGINEER

Dr Johan Steyn

Acting General Manager

Nicole Sweeten

PRINCIPAL Process Engineer

Rudie Theron

Manager Projects

Nico van Hoepen

Senior Process Engineer

Heine Weitz

LEAD PROCESS ENGINEER

Marinda Zietsman

Manager Administration

PROCESS ENGINEERING TEAM

FROM LEFT TO RIGHT:
Tumelo Makgoale, Dr Johan Zietsman, Heine Weitz, Nico van Hoepen, Nicole Sweeten

MULTIPHYSICS TEAM

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

OPERATIONS TEAM

FROM LEFT TO RIGHT:
Dr Johan Steyn, Charlotte Hollenbach, Dr Johan Zietsman, Edna Monyepao, Marinda Zietsman, Rudie Theron

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.

Dr Johan Heyns

LEAD MECHANICAL ENGINEER

Johan has an extensive background in the development of computational mechanics solutions to help clients gain better insight into their processes and products. To formulate these solutions, he leverages his combined experience in mechanical engineering, software and algorithm development.

He leads the Multiphysics group that develops custom CFD and FEM capabilities for the pyrometallurgical industry.

Charlotte Hollenbach

Manager Projects

Charlotte has a passion for organisational communication and sees the fundamental need for good communication structure and channels inside the project management function. She also believes that the stability of an organisation’s foundation lies within the implementation of good, solid processes. Her BA(Hons) Integrated Organisational Communication (UNISA) qualification stands her in good stead as a project manager at Ex Mente. Charlotte applies her communication skill to the overall planning, scheduling and monitoring of projects.

Tumelo Makgoale

INTERN PROCESS ENGINEER

Tumelo is a metallurgical engineer, currently finishing his master’s degree. 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.

Willem Roos

SENIOR MECHANICAL ENGINEER

Willem is a mechanical engineer with a newfound interest in thermochemistry. He is part of the Multiphysics modelling team at Ex Mente where he contributes to the models that are developed for clients.

Dr Johan Steyn

Acting General Manager

Johan is an experienced business manager who has been leading teams in exponential growth for more than 20 years. His qualification, Ph.D. (NWU, Engineering), and background in strategic growth, resolving growth constraints, digital transformation, organisational performance and competitiveness are specifically relevant to the current dynamics of Industry 4.0, IOT, AI and the digital revolution. As acting general manager, Johan supports operations management to create an environment in which the Ex Mente team can do great things.

Nicole Sweeten

PRINCIPAL Process Engineer

Nicole started at Ex Mente in 2017 and helps clients design new pyrometallurgical production routes, from concept development to pilot testing, and has also assisted smelters with improving their operations. Thermochemistry is one of her favourite and most useful tools for gaining deeper insights into pyrometallurgical processes.

Nicole completed her BEng Chemical Engineering degree at the University of Pretoria in 2011. She became intrigued by furnaces and pyrometallurgy whilst designing off gas systems and energy recovery technologies at a variety of smelters in South Africa and abroad. Her new passion saw her return to the University of Pretoria to complete her MEng in Metallurgical Engineering.

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.

Nico van Hoepen

Senior Process Engineer

Nico is trained as a chemical engineer but spent virtually all of his career as a pyrometallurgical process engineer. His process design experience ranges over a variety of commodities from large ferro-alloy furnaces to mineral wool melters, successfully starting-up these furnaces in more than a dozen countries and assisting clients across an even wider geographical area. He is fascinated by the mineral variety under our feet and the inexhaustible new ways of transforming it for our common benefit.

Heine Weitz

LEAD PROCESS ENGINEER

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.

Marinda Zietsman

Manager Administration

Marinda has been with Ex Mente for the past 20 years, supporting the team. Her main areas of responsibility are finance, human resources, legal, business management and software sales.