Gold is still currently being mined around the world. Countries such as South Africa and Australia are believed to have enough gold in the earth to keep operations going for the foreseeable future. The amounts are expected to continue becoming more scarce however. Because geological processes were different in each area, the gold being extracted is mixed with other minerals in different ratios. The exact percentage of gold within the gold ore being harvested is called the "grade"
What is the average gold mining grade?
There are two possible answers to this question. There can be an average for the entire world, and an average for a specific site or region. The most common use of gold mining grade average is that of the regional level. No matter what the percentage is, it is almost always profitable to extract the ore. The specific calculations are in a ratio of grams per tonne. In South Africa the average gold ore grade is about 8-10 grams per tonne for the better mines and 4-6 grams per tonne for the lower quality underground mines. Australia has an approximate average of 3-4 grams per tonne of gold ore. Global averages for mines run at about 1-2 grams per tonne.
How does grade effect an operation?
The higher the gold mining grade of the ore being extracted means the more profit for the same amount of work a mining outfit will receive. As mentioned before however, the scarcity and demand of gold means even in small quantities it is worthwhile to mine. After the gold has been refined the quality should be the same from any of these mines. Gold is a element bound by scientific laws, so basically gold is gold. The only thing that would make refined gold a different value ounce for ounce would be if it was not refined to be pure enough.