The rate of oxygen consumption in a gold heap leaching operation is 6.67 10⁶ l/(m² s) at STP, and 3% of the oxygen is consumed by the gold dissolution reaction involving cyanide. Estimate the rate of gold dissolution by cyanide leaching if the 15-m high heap contained 1500 kg/m³ of material assaying at 2 g gold/ton if the rate-limiting step is oxygen penetration. How long would it take to extract all of the gold at that rate? How long would complete extraction take if only 0.45% of the oxygen were utilized for the cyanide-gold reaction? Answer: 541 days