In early times Egypt was the leading producer of goldstone. They often bragged that in Egypt there was more gold than dirt and it was used extensively in their society. Much of the early clean mining was done by a method of mining called fire-setting. In this method, fire is created against the face of a rock.
Once the fire has been burning for a while and the rock is hot, it is doused in water. The shock in the change in temperature causes the rock to break apart.
This type of reaction can commonly be seen in the glass. If you take a glass straight from the dishwasher, while still very hot, and drop it in a pitcher of ice water it will likely shatter. This principle is referred to as a thermal shock and for a less dangerous example, you can drop an ice cube into a glass of warm water and watch it crack.
Fire-setting was mostly used in opencast mining because in underground mines the smoke and fumes tend to linger. This method of mining was frequently used in conjunction with hushing by the Romans. Hushing involves flushing an area with a large volume of water to help reveal veins of mineral ore.
Large tanks of water would be built on the top of the hill and rapidly released to expose potential areas that might contain gold.
This method required a lot of water and when used in conjunction with fire-setting was used to help carry the rocks and other debris that are created by fire-setting. Hushing is most effective on large steep slopes because it allows the water to build up a tremendous force.
Hushing was also used in combination with undermining by the Romans. Undermining involves digging a passage or shaft below a hill. Wood supports are used to keep the shaft from collapsing. After the shaft is completed, the wooden supports are burned, which causes the shaft to collapse. This results in the hill collapsing on top of itself.
Hushing was then used to carry away the dirt and debris and expose any precious metals. Undermining was frequently used during castle sieges to cause walls or towers to collapse as well.