Alchemy or Miscalculation

A metallurgist mate of mine pointed out that RED has discovered the ancient art of alchemy or they can’t do simple maths. Has to be one or the other.

RED reported they had a stockpile of 195,000t at 2.43 g/t Au on 7/1/15. They then reported they had processed 64,902t at 3.49g/t Au on the 28/2/15 and had a remaining stockpile of 130,000t at 2.46g/t Au.

With no additions to the stockpile (they state ore mining will resume in April, obviously after dewatering the pit) how is it that the remaining stockpile (130,000t) grade increased to 2.46g/t Au when the grade of processed ore was 3.49g/t Au

To reconcile the stockpile grade is simple. By subtracting the tonnes x grade of ore processed from the original stockpile tonnes x grade and dividing by the stockpile tonnage at the end you derive the final stockpile grade; as per the following formula: ((STb x SGb) – ((PTe x PGe))/(STb – PTe) = SGe

So RED gets the final stockpile tonnage near enough 130,000t (reported) vs 130,098t (reconciled). So far so good.

But the reported grade of the stockpile on 28/2/15 is 2.46g/t Au versus a reconciled grade of 1.90g/t Au. How can this be? RED has either arbitrarily added 0.54g/t Au or 29% to the grade/value of the remaining stockpile or there are some serious problems in their grade analysis (positive grade bias) at the mine which may include any part of the mine production process.

The grade figures appear fudged (based on mathematical analysis above and the naked eye! ) or they made a miscalculation and reported the wrong remaining stockpile grade number on the 28/2/15;  but yet there has been no announcement from RED.  It’s simple maths even for a metallurgist.