A conservative estimate
From the fact sheet:
In calculating the figure and developing the methodology, we consulted a number of experts with statistical, technical, academic, and scientific backgrounds.
It is given in short tons, and represents the average amount of mine wastes generated by gold mines around the world, in order to produce an average for an 18 karat, 0.333 oz gold ring. It is based on a representative sampling of publicly available mine data that is reported by mining companies to their shareholders, and data published by www.infomine.com and the US Geological Survey at minerals.usgs.gov.
The following components were factored into the number:
- The average amount of waste produced per ounce for underground mines (see “a conservative estimate” below) and for open pit mines.
- The total amount of gold produced for each type of mine in 2001.
- The weight and purity of a gold ring