Modern Mining April 2016

COVER STORY

The Platreef – the Merensky in all but name The Platreef project has been the subject of one of the most intense exploration programmes ever undertaken for a mining project in Africa. The initial focus was on near surface mineralisation but in 2007 a deep exploration programme was launched which led – three years later – to the identification of the Flatreef deposit, which lies within a flat to gently dipping portion of the Platreef mineralised belt at a relatively shallow depth of 700 m to 1 100 m below surface (over a strike length of 6 km).

D r Danie Grobler, Head of Geol- ogy for Ivanplats, recalls that the deep drilling of the Flatreef involved as many as 30 drill rigs on site simultaneously with over 700 km of core from more than 1 200 holes be- ing generated in the period from the late 1990s to 2015 – all of it now stored at Ivanplats’ of- fices and core shed in Mokopane. Some of the drill intercepts during this campaign were phenomenal and in October 2013, for example, Ivanhoe’s Executive Chairman, Robert Fried- land, and its CEO, Lars-Eric Johannson, report- ed what they described as an “unprecedented 90 m intersection” of 4,51 g/t of platinum, pal- ladium, rhodium and gold plus 0,37 % nickel and 0,20 % copper. This included a 40,79 m section grading 6,88 g/t 4PGE. The Flatreef’s indicated mineral resources total 214 Mt grading 4,1 g/t (3PE+Au), 0,34 % nickel and 0,17 % copper at a 2,0 g/t (3PE + Au) cut-off grade containing an estimated 28,5 mil- lion ounces of platinum, palladium, gold and rhodium, 1,61 billion pounds (725 747 tonnes) of nickel and 794 million pounds (360 152 tonnes) of copper. The current resource was

Exploration, and Tim Dunnett, a senior geolo- gist with Ivanplats, presented at PDAC in 2014 in which it is stated that the Flatreef can be viewed “as a hybrid deposit type with internal features and stratigraphic correlation consis- tent with the Merensky Reef, and economically attractive thicknesses (the Flatreef indicated resource averages 24 m thickness at a 2 g/t 4E cut-off) typical of Contact-type deposits.” 

Cross section through the Flatreef. The highest grades occur at the top of the Flatreef.

Personnel from drilling contractor Major Drilling studying drill core during the exploration phase.

published in 2013 and a new mineral resource estimate is expected later this year. The geological interpre- tation of the Platreef (and, by extension, the Flatreef) and the degree to which it correlates with the Merensky Reef is a highly technical subject – and a matter of some controversy in the geological commu- nity – but Grobler is in no doubt that the Platreef is, to all intents and purposes, identical to the Merensky. This view was more formally expressed in a paper he co-authored with Dr David Broughton, Ivanhoe’s Executive VP,

April 2016  MODERN MINING  29