Open-pit mines are large excavations dug into the ground to extract minerals. They are typically used for large quantities of materials such as coal, iron ore, or copper.
Underground mines are tunnels dug into the ground to extract minerals. They are typically used for smaller quantities of materials such as gold, silver, or diamonds.
Placer mines are areas where heavy minerals, such as gold or platinum, have been concentrated by erosion. They are typically mined by panning, dredging, or sluicing.