Intruded Concrete Plugs in a Deep Gold Mine: An Exercise in Quality Control, Assurance, and Performance Verification

Five horizontal concrete plugs were designed and constructed in a deep gold mine near Randfontein, South Africa. Intended to resist water heads of up to 1500m, they were up to 30m long and measured 4 by 4.5m in cross-section. Each plug was constructed in four separate, contiguous segments using the mortar intruded preplaced aggregate ("colcrete") process. They have been designed conservatively to provide a service life of at least 100 years. This paper focuses on the construction aspects, and in particular the very intense levels of QA/QC and performance verification which were considered appropriate to the project, given the potentially horrific consequences of failure to the mine labor.