Jack Caldwell - Mining Engineer - Robertson GeoConsultants

Mike Gowan of Golder Associates in Australia has enabled me to post at this link a PowerPoint presentation of a talk he gave earlier this month in South Africa. At the link is the PowerPoint in pdf format. It is a big file and may take time to download, but persist, for the wait is worth the reward once you go through the presentation.

Mike was born and brought up on the Witwatersrand, and has lived and worked tailings ever since. This presentation is at once intensely personal and of international significance. Here for the first time, that I am aware of, is a great collection of photos and figures showing early mining and slimes dam practice in South Africa. Here are pictures I have not seen before of the failure of slimes dams. Here are snippets of stories of George Donaldson who pioneered tailings practice in South Africa. (I got on the wrong side of him early in my career so have never written about him.) Mike resuscitates his contributions.

The presentation consists of nearly 140 slides, so it is inevitable that Mike would take us on a world-wide, whirl-wind tours of the tailings facilities he is now working on. Rock dam starter dikes subtended by upstream tailings in China. Dealing with high rainfall in the Solomon Islands. Compacted cyclone underflow in Chile. Diamonds in Botswana. Concrete-face waste rock dams in Peru. HDPE covers to limit evaporation in Oman.

Here are pictures and thoughts about filtered tailings, thickened tailings, paste for backfill, dust, commingling, and nearly all the multiple aspects of the science, engineering, and art of tailings management. Mike is master of them all.

This is an extra-ordinary collection of photos and technical details. Make sure you leave yourself time to pour over and savor the details.