Placerbars

Placerbars are a type of mineral deposit formed by mechanical concentration of heavy minerals in stream beds or alluvial deposits. The process of placer formation involves the weathering of rocks containing valuable heavy minerals, such as gold, platinum, diamonds, or tin. These minerals are then transported by water and, due to their high density, tend to settle in areas where water flow slows down. Such locations often include bends in rivers, areas behind obstacles like large rocks, or at the junction of tributaries.

The concentration of these heavy minerals in placer deposits is a result of natural sorting and gravity. As water carries sediment, lighter materials are washed away, leaving the heavier minerals behind. Over geological time, this process can lead to the accumulation of significant quantities of valuable minerals, making them economically viable for extraction. Prospectors have historically sought out placer deposits, especially for gold, using simple tools like gold pans to identify and collect the concentrated minerals.

Placer deposits can be found in various geological settings and are not limited to active river systems. Ancient or "fossil" placers can exist in areas that were once riverbeds but are now buried or uplifted. The exploration and exploitation of placer deposits have played a significant role in the history of mining and resource extraction worldwide.