In 30 years, average ore grades have declined from 15 grams of gold a ton to about 5 grams.

Almost all of Hubbert peaks must be put in the context of high ore grade.

Average ore grades are in decline for most minerals, yet production is increasing.

Key environmental indicators that reflect increasingly expensive production are primarily associated with the decline in average ore grades of many minerals.

There is an abandoned mercury mine in Sızma with the ore grade of 0.6-1 % which was once a major economic activity of the town.

Declining ore grades at some mines can also be a reason for care and maintenance announcements.

The average ore grade was 0.06% and total production from the three pits was about 11,000 tonnes of uranium.

Resources change over time with technology and economics; more efficient recovery leads to a drop in the ore grade needed.

Average ore grades were 16.0 ounces per ton silver and 0.68% copper.

The recoverable ore grade at the mine is about 0.26 carats (52 mg) per ton.