The process starts with ore extracted from mines or a river, which is heated to very high temperatures and then cooled.

Rocks extracted from mines were brought to the main facility to be crushed and treated with mercury to purify the silver.

Often, the treasure of which they were stripped had been extracted from mines worked by slaves in stolen colonies.

In the mountains around the southbound tunnel brown coal has been extracted from mines since the 1770s.

It appears that marble was not then, like today, extracted from mines, but was quarried in great quantities.

Many coals extracted from both surface and underground mines require washing in a coal preparation plant.

In order to fight back, the king needs to extract magical ore from mines, which can be used to forge more powerful weapons.

From 1920 to 1963 oil was also extracted from underground mines.

The main raw material for energy production - oil shale - is extracted from mines owned by the company.

It underscored the environmental and social costs of the technologies needed to extract the ever-more-valuable ore from modern mines.