D.Phil. (Sociology) / In this thesis I am examining the National Union of Metalworkers of South Africa (NUMSA) and Solidarity‘s responses to technological changes at the ArcelorMittal (formerly known as Iron and Steel Corporation of South Africa (Iscor)) Vanderbijlpark Plant in the south of the Gauteng province between 1989 and 2012. As part of the restructuring plans of the Apartheid government, Iscor South Africa was privatised in 1989. At that time the plant was also in a process of restructuring, which included technological changes and work reorganisation, the objective of which was to prepare Iscor South Africa and the plant for competing in a global steel market. Therefore the subsequent technological changes in the plant were also part of the plant‘s positioning in the global competition of the steel market. The ownership of the plant by ArcelorMittal International after 2006 meant that the plant was fully integrated into the global steel market because it became part of the other global plants of the ArcelorMittal International Group in other parts of the world. Technological changes and work reorganisation led to a massive displacement of workers at Iscor South Africa. For example, in 1988, Iscor had about 59 000 employees and this number was reduced to about 9 300 employees in 2010. The key objective of the thesis is to conduct a sociological analysis of trade union responses to the technological changes at ArcelorMittal Vanderbijlpark Plant. One of the discoveries of this thesis is that both trade unions – Solidarity and NUMSA- were not proactive in responding to technological changes at the plant. They argued for more consultation on technological changes, training, and deployment of workers who had been displaced by machines, work reorganisation, and retrenchment packages for retrenched workers. Solidarity, a predominantly white workers‘ union, with its skilled workforce did not use its membership‘s strategic location at the point of production to help it proactively to respond to technological changes. On the other hand, NUMSA, a predominantly black union which was part of a vibrant antiapartheid movement with traditions of grooming worker intellectuals, did not respond proactively to technological changes at the plant.Even after the wave of restructuring and technological changes of the 1990s to early 2000s, both unions did not move away from a reactive approach towards a proactive approach to production technology. The two unions did not combine reproduction and production issues in their bargaining strategies. The unions were still focusing on wages or reproduction as a strategy of engaging factory owners. Production in the form of technological changes and work reorganisation was not being addressed by the union and yet changes in production processes play a major role in determining the number of workers in a plant and the profile of the workforce as shown in this thesis. The reactive responses of both trade unions and a focus on wages is theorised as reproduction reductionism. This means that unions tend to focus on wages and other spheres of income such as politics of ‗upward mobility‘ which play a central role in reproducing workers and their leaders. The focus on these issues means that the unions are prioritising reproduction over production. This then leads to management of the plant having free reign in the sphere of production and technological changes.