Van der Bijl was negotiating for the purchase of the farm Kookfontein, near Meyerton, for Iscor’s second steel works when Louis Marks (son of Sammy Marks) drew his attention to the problems he may expect if, as was proposed, the effluents from the works were to be disposed of in the Klip River. Marks anticipated that the Rand Water Board would object because of contamination of the Klip River water which would enter the Vaal River above its intake station at Vereeniging. Marks provided an alternate site, owned by Vereeniging Estates, which was downstream from the Board’s intake station. Agreement was reached whereby the site was purchased at £100 an acre, and in 1941, construction of the plate mill began.

While the erection of a new plate mill progressed, the site for the new steelworks and town was acquired (an eventual total of 95 square kilometers), much of it from the Vereeniging Estates company which had been established by Sammy Marks. The planning for the town of Vanderbijlpark then commenced. On 28 November 1944 the Vanderbijlpark Estate Company (Vesco) was registered as a non-profit-making company with its income and assets applied solely towards the objectives of the company and the constant improvement of the town for the benefit of its citizens. Land for the town was transferred to this company by Iscor at cost and it had the task of creating the town, with rights to resell land for residential, business or other purposes.