Gold deposits and gold mines are divided into categories depending on the average proportion of gold that the ore at the site contains. In fact, it is also referred to as ore grade. A high quality mine will have a higher ore grade, while a low-quality mine’s ore grade will be on the lower side. A gold mine with a high grade requires less effort in extracting an ounce of gold from the ground. It reduces input costs for the mining company, for less ore needs to be dug out.
During the 19th century, high grading referred to miners concealing precious metal ore. The so-called high-graders would hide gold in their lunch boxes. As a solution to the persisting problem, mining companies would open the workers’ lunch boxes, turn out their pockets, and require them to take a bath once their shift was over.
How are precious metals graded?
All precious metals are graded according to the proportion of the metal in the ore excavated. The most common metric used to represent the grade of an ore is grams per tonne (and is shortened as g/t for ease of use). The value of a mine digging up precious metals is calculated using the total estimated weight and the grade of the ore, and the difficulty of extracting and distributing the ore.
Precious metals are found in various sites all over the world.
They can be found underground, in open pits, under water bodies, and as single pieces just resting on the ground. That said, every place that sprouts a few pieces of a precious metal cannot be graded. Grading is applied only to open pits and underground mines.
What role does the World Gold Council play?
The World Gold Council sets standards for high-grade and low-grade gold ore. It is a non-profit organization created to promote the global use of gold and gold products. The council researches various gold mines and creates standards that are used to evaluate gold mining prospects, in addition to marketing and helping gold producers.
Although open pit mines have a lower grade, they are considered valuable for the lower operating costs required to dig the gold out.