Is it Time to Reduce the
“5g/t Rule of Thumb” ?

Underground mining has a number of “rules of thumb”, one of which that has stood the test of time, is that for most mines you need 5g/t in order to mine underground. And if it is refractory add 20% so it becomes 6g/t.

At 5g/t it meant that the mine should be able to achieve a capital return and return the invested money back, allowing for the odd occasional thing to go wrong – or in other words provide a reasonable margin for error.

Paste Failures Provide a “Wake-Up” Call

I must admit that when I first encountered paste being used to fill stopes instead of concreted tailings and the way it behaved, I thought “WOW this is fantastic, looks like rock, fills the void perfectly, can be cable bolted, can be mined against, etc”. So it is understandable how complacency occurred, and why failures in the past year have been met with surprise.

PDU fires up the West African Golds

Any doubts anyone may have had about Burkina Faso being the current world exploration “hot-spot” were quickly dispelled by the behaviour of the West African gold shares in the week of PDU (Paydirt Down Under) in early September 2010.

The Mega Gold Mines are Coming

In the SMH of 29 November 2010, it was reported that the Kalgoorlie Super Pit was Australia’s biggest producer in the September Quarter of 2010 with 202,000oz, followed by the new Boddington mine at 180,000ozpa. Both mines producing ~800,000ozpa.