To GeoTDR
Not sure if you are still looking for answers, and also what exactly what you are looking for. Since time immemorial tailings compact at an average of 0.625 cu metres/ton. and normally hold 10% moisture, or would be saturated at 20% moisture. At this rate a 45 hectare dam is generally sufficient for 100,000 tons/month with a monthly rise of 10cm. These numbers apply in North America as much as sub-saharan Africa. For info on dam stability check out some of the early RSA researchers G.W. Donaldson JSAIMM vol 61 1960, or G.E Blight Civ. Eng SA vol 11 1969.