Before you can beat or smelt or cast copper, it must be taken from the ground. In the beginning of mining, people simply picked up pieces of copper or gold, two metals that have a distinctive color, are found in large masses, and can be worked with primitive tools such as stone axes and hammers.
As civilizations began to use and depend on metals, the amount of pure copper or copper minerals found right at the surface was not enough anymore. Other ways of obtaining copper had to be developed.
These earliest miners quickly realized that some copper minerals exposed on the surface were the tip of a deposit going down into the earth. Using stone, and later copper and bronze implements, the miners dug down to follow the deposit. The implements were crude picks, hammers, chisels and shovels. Since no method of blasting was available, miners were confined to much slower and more tedious methods of opening the rock wall or face. The miners picked at loose stones with their tools. If no cracks or loose stones were available, fire was used to create sudden changes of temperature to crack the rock. Logs were piled against the rock face, then set afire. When the rock was very hot, the fire was quenched with water. Then miners used their tools to pull out the loosened rock. ...
Nu is mijn vraag zeer simpel. Hoe weten ze zo'n dingen zelfs?