An additional 200 to 300 million tons of waste rock with little or no ore are also removed from open pits each year.

Because the waste rock and soil have little or no practical use, they are generally stored on land near the mine site.

At the same time the mining method is designed to ensure that no waste rock needs to be hauled to the surface.

Tiny particles of gold sticking to the waste rock were gathered in this way.

Most of the waste rock from this operation is expected to be placed in the depleted Main pit.

Leaching of metals and acids from waste rocks into the environment is a valid concern.

If the waste rock is destined for sale, he said, then the mine needs a separate quarry permit.

If a mine also wanted to sell waste rock, he said, then it must apply for a separate permit.

Concentrate can also refer to the residue valuable metal from which most of the waste rock has been removed.

At its peak, the industry produced approximately 170 tonnes of waste rock annually.