What is truly amazing is how this pad is designedand that the embankment was not built at least twice as high for containment in the event of a 60 million tonne slope failure.
This sloped leach pad is constructed in a valley by continued piling of millions of tonnes of loose 10mm ore sitting directly on a steep slippery liner, and that ore is being continually saturated through miles of pipe networked throughout the pad.
If the dozer operator and the other accounts of a pipe leak they couldnt find are correct, it wouldnt take much to undermine a portion of the pad causing a soft spot and the rest is history. It just needed a nudge, and the dozer may have been just enough to start that nudge.
This would explain why the dozer simply slide down on top of the material, and didnt violently roll into the developing slide as the base slide out from underneath him.