Placer mining was the most widely used method of mining for gold primarily because it was affordable to a large number of prospectors. This method allowed individuals to search for gold in easily accessible locations like riverbeds, streams, and sediment deposits without the need for expensive equipment or extensive mining operations. It enabled many ordinary people, not just large companies, to participate in gold mining during events like the Gold Rush.
While other factors contributed to the popularity of placer mining, such as the potential for striking it rich, the low barrier to entry and accessibility were key reasons for its widespread use.