1. Introduction
In a country such as South Africa where many types of minerals are available and distances are great hydraulic transportation of solids in pipelines may become the most economical means of bulk transportation. For this reason the National Mechanical Engineering Research Institute (NMERI) of the Council for Scientific and Industrial Research (CSIR) established, some ten years ago test facilities for fundamental and applied research in this field. These facilities have been used for a number of important investigations for industry.
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