The Companhia de Diamantes de Angola, or Diamang, mined for diamonds in colonial Angola from 1917 until independence in 1975. The enterprise’s Health Services Division (SSD) was responsible for supplying mine managers with an African labour force comprised of healthy, and therefore productive, employees. In practice, though, this otherwise ‘healthy’ system did not always work. While SSD personnel attempted to fulfil their charge by implementing a series of screening measures, production targets and a scarcely-populated regional labour pool regularly prompted senior officials to compel the SSD to clear recruits who were otherwise unfit for mine service. Drawing upon interviews with former SSD staff and African labourers, as well as company and colonial archival sources, this article focuses on the interplay over time between the SSD, the company’s production demands and these labourers.