The South African Journal of Industrial Engineering

In Memoriam: Prof D. R. Snaddon

2025-08-29

Prof Douglas Roy Snaddon (12 May 1944 - 18 August 2025)

Prof Snaddon was Head of Industrial Engineering at the University of the Witwatersrand (Wits) for many years and held the prestigious Barloworld Chair of Industrial Engineering at Wits, building and steering the discipline with great vision, laying strong foundations and shaping a unique blend of Industrial Engineering suited to South African industrial needs.

Prof Snaddon taught and inspired many students to love Industrial Engineering, which he promoted actively in South Africa and outside the country. In 2011, he left Wits to take up the position of Professor and Director of Mechanical Engineering at the Polytechnic of Namibia, where he started Industrial Engineering courses and qualifications in Namibia and encouraged the introduction of Industrial Engineering in Botswana.

Prof Snaddon authored numerous papers and articles, as well as two books related to Industrial Engineering. He was an Honorary Fellow of the Southern African Institute for Industrial Engineering (SAIIE) and served on the SAIIE Council for many years, as well as President in 1994.

During his retirement, Prof Snaddon kept regular contact with the Industrial Engineering Department of Wits University, giving the occasional lecture, providing valuable advice to the faculty, and regularly speaking at student evenings and prize-giving ceremonies.

Prof Snaddon will be remembered for his incredible energy, drive, enthusiasm, wit, humour, forthrightness, non-compromise with excellence and kindness, generosity, and many other qualities. He will be dearly missed by all who knew him, particularly his children: Susan, Collin and Bruce and his grandchildren.

Note from the Editor

Corne Schutte — 2025-08-29

"Excellence is never an accident. It is always the result of high intention, sincere effort, and intelligent execution." Aristotle

The Southern African Institute for Industrial Engineering (SAIIE) Annual Awards Ceremony took place on 21 August at the historic Country Club Johannesburg, where two journal-specific awards were presented:

The SAIIE Award for the Best Industrial Engineering Paper, published in the South African Journal of Industrial Engineering (SAJIE), was this year presented to Paul Burger, a Master’s student at North-West University, for his article “Future Mines’ Compressed Air Planning Using Digital Twin Simulations.” The paper was co-authored with Dr Jan Vosloo and Dr Jean van Laar. Read the article here: https://doi.org/10.7166/35-3-3094.

The SAJIE Editor Award was presented to our meticulous Technical Editor, Eldon Burger from Stellenbosch University. Eldon has fulfilled this critical role with exceptional efficiency, often working quietly behind the scenes. The consistently high technical quality of every article published in SAJIE is a direct result of his dedication and hard work.

Our upcoming issue will be a special edition, featuring the best submissions from leading conferences in South Africa. The review and selection process for the SAIIE conference has already been completed, and we look forward to showcasing the innovative research and fresh thinking that emerged from these events.

This edition has a total of 15 articles, with 13 articles from authors with South African connections and the balance from international authors.

If you have suggestions on how we can take this journal forward, please let me know.

Corne Schutte

Editor

A Practical Method for Joint Inventory Replenishment under Supplier Constraints

T. S. Winter — 2025-08-29

Retail distributors routinely encounter a variety of supplier constraints, including those related to the size and timing of inventory replenishment orders, such as minimum order quantities and minimum reorder intervals. In addition, constraints on the transportation of replenishment stock, such as minimum order values and container filling requirements, necessitate the joint replenishment of commodities in the case of multi-commodity inventories. These supplier constraints typically lead to larger order quantities and excess inventory, giving rise to the need for a joint replenishment model that is capable of mitigating the impact of increased inventory levels. In this paper, we propose a novel simulation-optimisation modelling approach in support of the complicated joint replenishment decisions faced by inventory managers in the presence of the aforementioned constraints. The modelling approach is capable of consolidating multi-product inventory replenishment orders, guided by minimum reorder intervals and minimum order quantities, subject to container filling and/or minimum order value constraints. It aims to optimise safety stock levels heuristically with a view to reducing the increased inventory costs associated with the particular supplier constraints imposed. We show in a real-world case study that the modelling approach is capable of leading to substantial cost savings during joint inventory replenishment decisions.

Developing an Enterprise Risk Management Roadmap for the Passenger Rail Agency of South Africa

T. Mangcu — 2025-08-29

This research explored the development of an enterprise risk management (ERM) roadmap for the Passenger Rail Agency of South Africa (PRASA) amid growing business risks from global financial shifts and pandemics. It emphasised a holistic management approach to address PRASA’s ERM difficulties and opportunities. It also advocated a tailor-made ERM roadmap underpinned by an action priority matrix. Given the lack of ERM literature for public enterprises, this study aimed to bridge that gap using a mixed-methods approach to identify barriers, enablers, and opportunities for ERM implementation. The findings suggested that a customised ERM roadmap would enhance PRASA’s governance, efficiency, risk, and resilience, and contribute to value creation.

Route Optimisation and Expansion of BisKita Depok Service Corridor using Set Covering Problem Approach

A. B. Prasetya — 2025-08-29

Sustainable transportation is crucial for Indonesia to support urban development and to reduce carbon emissions. Depok, a satellite city of Jakarta, faces problems such as traffic congestion and reliance on private vehicles. In July 2024, the government launched the BisKita Depok service to improve public transport accessibility and to reduce emissions, aligning with Sustainable Development Goals 11 and 13. Using the set cover problem model, this study optimises bus routes to expand their coverage and operational efficiency. The findings recommend strategies to establish BisKita Depok as a sustainable transportation model for other cities and provide actionable insights for reducing national carbon emissions.

Service Innovation Dynamic Capabilities Framework: A Case of Water Utilities in South Africa

L. Shabangu — 2025-08-29

South African water utilities’ capability to provide high-quality drinking water service is deteriorating, and the country faces a significant problem with continuous water supply because of rising water demand caused by high population growth, industrialisation, and agricultural activities. A quantitative methodology was used to collect and analyse data. Then a framework for service innovation’s dynamic capabilities was developed to address the deteriorating service capabilities in South African water utilities. The study's contribution is this framework, which integrates ordinary capabilities, managerial dynamic capabilities, service innovation capability, and new and emerging technological concepts to address the water supply problem.

The Interplay between Sustainability Initiatives and Capital Structure Dynamics using Machine Learning and Shap Analysis: Are we there yet?

V. M. Maluleke — 2025-08-29

This research explores the relationship between sustainability performance and capital structure in industrial and resources firms listed on the Johannesburg and London Stock Exchanges. The study leverages environmental, social, and governance factors to assess their influence on capital structure decisions using machine learning techniques, including Shapley additive explanations analysis. The findings reveal that traditional financial metrics, such as operating profit margin and total assets, are more significant predictors of capital structure than sustainability factors. While environmental, social, and governance factors play a role, their impact on capital structure is limited. The study highlights the importance of integrating sustainable practices with financial performance.

South African Sawmill Industry Clusters and Benchmarking Practices

V. Tshavhungwe — 2025-08-29

Sawmills tend to be concentrated where there is an adequate supply of logs for processing. The concentration of these sawmills presents an excellent opportunity to form successful industry clusters and for firms to be benchmarked against other firms in the industry. The study evaluated benchmarking practices in the South African sawmill industry. It used an online survey methodology to examine how cooperation between the industry players could enhance the industry’s competitiveness. The results gave valuable insights into the views of individuals working in various sawmills. The study could assist sawmillers to evaluate their processes and to consider implementing various forms of benchmarking in order to improve their sawmills in collaboration with multiple stakeholders.

Understanding Customer Needs and Preferences in Head-mounted Display Virtual Reality Experiences

K. Kim — 2025-08-29

This study investigated consumer perceptions of head-mounted display-based virtual reality systems, focusing on factors influencing adoption, usage, and purchase decisions. Using a survey of 112 participants, the research examined the technological, psychological, and economic considerations shaping user experiences. Factor analysis identified six critical dimensions: usefulness, usability, capabilities, content and system satisfaction, engagement, and risk. Regression analyses revealed that engagement is the primary driver of purchase intention, while usefulness predominantly influences usage intentions and future adoption perspectives. Content and system satisfaction emerged as an additional determinant across both adoption and purchase behaviours. Despite positive perceptions of immersion, realism, and originality, users expressed concerns about content quality and cost. These findings underscore the need to enhance engagement and usefulness, alongside improving content and system satisfaction, to foster a broader acceptance and integration of head-mounted display virtual reality technologies. Limitations in the survey’s regional focus are acknowledged, suggesting the need for cross-cultural studies. This research offers actionable insights for the developers and stakeholders of head-mounted display virtual reality systems, contributing to the advancement and popularisation of VR systems.

Feature Analysis of Learner Adaptation across Socio-Economic Divide in South African Public High Schools

J. Visser — 2025-08-29

Persistent socio-economic disparities in the South African education system hinder learner progression. This study examines the factors shaping learner adaptation across socio-economic divides in public high schools, focusing on the contrasting experiences of learners from lower-income backgrounds in different school environments. Using data from the 2022 General Household Survey, the study applies factor analysis, multiple regression analysis, structural equation modelling, and machine-learning techniques to identify key determinants of learner progression, such as family structure, supported retention, welfare income, and household conditions. The findings show the significant role of school meals, age-appropriate grade placement, and consistent attendance in academic success. These insights point to the need for targeted, context-sensitive interventions to address the socio-economic barriers to educational achievement in post-apartheid South Africa.

A Conceptual Framework for Timber Adoption in the Construction Industry

B. Verhage — 2025-08-29

This study explored the key human behavioural factors influencing the adoption of timber and engineered wood products in the construction industry by integrating the key constructs of the theory of planned behaviour and the unified theory of acceptance and use of technology. The study identified relationships between attitude towards behaviour and performance expectancy, subjective norm and social influence, perceived behavioural control and facilitating conditions, and effort expectancy in the context of timber adoption. The proposed framework provides a theoretical foundation for further research on the adoption of timber in the construction industry.

Improving Organisational Learning in Project-Based Organisations Through the Translation of Project Lessons Learnt into Project Risks

C. Bredell — 2025-08-29

This study examines the translation of lessons learnt into risks in project-based organisations to improve organisational learning through the development of a knowledge transfer model. A qualitative analysis of semi-structured interviews, a focus group interview, and an organisational repository review in a single case study organisation revealed that framing lessons as risks enhances organisational learning by strengthening critical practices such as systematic problem-solving, learning from past experiences, and efficient knowledge transfer. The proposed model configures the application of risk-phrased lessons learnt to promote the transfer of knowledge and to foster organisational learning in project-based organisations.

An Economic Order Quantity Model for Imperfect and Deteriorating Items with Freshness and Inventory-Level-Dependent Demand

D. Coghlan — 2025-08-29

The sale of many products is influenced by the characteristics of the products and the behaviour of the consumers. This is particularly true of food items. Consumers of most food items want them fresh; thus, while items that are edible but have lost some of their freshness might be sold, the demand usually drops, and the closer the expiry date, the lower the demand for such products. Another factor that is known to affect the sale of many items is the attractiveness of the stocking pattern. Seeing a large stock of consumable items tends to attract consumers; hence the stock level dependence of demand. An additional characteristic of such products is that they continue to deteriorate; thus affects both the quality and quantity of such items, as the overly deteriorated ones are removed from the stock of saleable items. Consequently, the stock level reduces owing to both demand and deterioration. This description fits many agricultural products such as fruits and vegetables. Another characteristic of such products is the possibility of their being imperfect when they are received, as some stock might be damaged by harvesting, handling, or transportation. In this research, we develop a mathematical model to determine the optimal lot size for an item having all these characteristics, with the profit function as the model objective. We used a case of banana as the numerical illustration. Sensitivity analyses of important model parameters were conducted to demonstrate the model’s robustness. The findings were that the date of expiry, the scale of demand, and the selling price of perfect products were the main constituents that affected their profitability. This model should find ready application in most stores where fresh consumable food items such as fruits and vegetables are managed.

Inventory Management Strategies to Enhance Resilience Among Automotive Suppliers

K. R. Ramdass — 2025-08-29

The increasing vulnerability of supply chain disruptions in the automotive industry had an adverse impact on production schedules, financial performance, and customer satisfaction. This research comprehensively analyses current practices, case studies, and interviews with industry experts to propose a framework for implementing resilient inventory management strategies. Examining the root causes and effects of supply chain disruptions has identified areas where strategic interventions could mitigate risks and highlight the role of digital technologies, such as the Internet of Things, in optimisingnventory management strategies. The findings emphasise the importance of real-time data analytics, diversifying suppliers, and improving the resilience of automotive suppliers.

Factors Influencing the Implementation of Project Risk Management in the South African Construction Industry

K. B. Masea — 2025-08-29

Effective project risk management is crucial for successful construction projects. However, the construction industry continues to face problems in implementing project risk management practices. This study investigates the barriers to and enablers of implementing project risk management in the South African construction industry. Semi-structured interviews of experienced industry professionals on a case study project were conducted to answer the research questions. The findings reveal that inadequate knowledge, communication breakdowns, financial constraints, and resistant attitudes are significant barriers to implementing project risk management. Conversely, leadership support, clear policies, and proactive engagement emerge as key enablers. A framework is proposed to address the barriers and to leverage the enablers, thus enhancing project risk management practices in the construction industry. This study contributes to the body of knowledge by providing actionable insights for construction organisations, policymakers, and stakeholders seeking to improve project outcomes through effective risk management.

A Practical Framework for Integrating Advances in Ergonomics to Improve Productivity in South African Small and Medium Enterprises

T. A. Mukalay — 2025-08-29

This study provides a practical framework for integrating advances in ergonomics into South African small and medium enterprises to enhance productivity. Informed by a comprehensive literature review and insights from the 2025 Applied Ergonomics Conference, the proposed three-phase framework comprises an ergonomics intervention trigger checklist and related productivity metrics; an integration matrix aligned with ISO 45001:2018 and ISO TR 12295:2014; and strategies to overcome adoption barriers. The framework incorporates participatory design, simplified assessment tools, and interventions such as wearable technologies. By addressing a gap in the research, this study offers a scalable, cost-effective framework that is tailored to the resource-constrained small and medium enterprises’ environment.

Scoping Review: Factors, Threats and Opportunities of Outsourcing Maintenance Activities in the South African Pulp and Paper Industry

W. Maphanga — 2025-08-29

Outsourcing is a tool to realise the strategic intent of an organisation. Before outsourcing maintenance services, the maintenance manager should consider the relevant factors, opportunities, and threats. The study aimed to perform a scoping review of the applicable factors, opportunities, and threats in the pulp and paper industry. The review also aimed to determine whether there was a gap in the literature from a South African perspective. Scopus and Web of Science were used as databases to collect 21 articles published from 2002 to 2021. Using ATLAS.ti, 11 categories in these articles were coded, and Sankey diagrams were used to visualise the data. The percentage strength of the correlations indicated recurring themes in the literature. The results found strategy through targeted outsourcing of non-core activities (50%), supplier performance (53%), and employee impact (15%) to be critical factors. Cost reduction (42%) and access to vendor expertise (21%) were key opportunities, while poor supplier performance (29%) and loss of organisational know-how (33%) were key threats. As a recurring theme, outsourcing was found to be common to industries in Europe, Asia, and North America. Based on the findings of the scoping review, it was concluded that there was an opportunity to explore the local context. It was recommended to use the findings and to determine whether these factors, threats, and opportunities could be applied to the South African context.