The Merriespruit tailings dam failure was a tragic event that resulted in loss of life and much damage to property owing to the extensive mudflow. Because of the restraints imposed by a long, drawn-out inquest/inquiry, attempts to establish the cause of failure required an exercise in intensive investigative engineering without the direct assistance of those who had good information on the likely cause. The investigations conducted on behalf of the State included a careful analysis of eye-witness accounts, evaluation of weather and hydrological data, assessment of tailings properties through both laboratory and in situ testing, the interpretation of satellite imagery, and overtopping studies in a small-scale field experiment. This paper provides further insight into various geotechnical aspects that were of particular relevance and records details of new techniques that are of wider technical importance. It also highlights the need for the involvement of appropriate expertise in the design and operation of major mining facilities above ground to prevent similar failures in future.
Water resource project developers have increasing accountability to more stakeholders and there are greater demands that project benefits be distributed more equitably, widely and transparently. In order for institutions in the sector to satisfy the aspirations and meet these demands, it is essential that they follow best practices. The key criteria for smooth project implementation and success now include stakeholder analysis, participation, co-operation, environmental management, integration and risk management, while new values include openness, transparency and cultural and environmental sensitivity. Best practices are partly established internationally, but may not necessarily be well defined or may require adaptation or nuances in local or regional circumstances. This paper systematizes and describes best practices according to planning issues that include integrated water resource management, participation and the environment, legal issues that involve compliance, technical issues that include technology choice, and project management issues.
A methodology for the rational economic evaluation of reinforced concrete structures in marine environments has been developed. The durability design approach employs realistic chloride propagation models within a full life-cycle economic framework. The cost implications of variations in materials, design and rehabilitation techniques can be evaluated over the full life of the structure to achieve the most efficient use of resources. The use of cement extenders, in particular, is shown to significantly improve the resistance of concrete to chloride ions, thereby allowing for a significantly longer service life with lower initial cost.
This paper reports on commissioned research into the technical and cost aspects of using hollow clay 'maxi' bricks in Western Cape house construction. Specifically, sample bricks were evaluated in terms of the National Building Regulations, a technical analysis was conducted of energy saving, dimensional co-ordination, structural strength, structural stability and rain penetration, and a framework for a comparison between the effect on house costs of the use of hollow clay and solid cement 'maxi' bricks was established.