How did the gold rush in America surge?

/kloc-At the beginning of the 9th century, after the independence of the United States, the imperial edict issued by the British government prohibiting immigrants from moving westward was abolished, and many immigrants from the eastern coastal areas and Europe crossed the Appalachian Mountains and flocked to the west. From the 1920s of 19, immigrants began to cross the Mississippi River and enter the newly expanded areas of the United States. 1848, people who went to California discovered a gold mine here, which immediately caused a sensation in the world and quickly formed an unprecedented gold rush. Many people leave their jobs at hand and rush to San Francisco, trying to realize their dream of gold panning. Because the sand in California is on the surface, the gold in the sand can be washed out with an ordinary washbasin. This gold rush made people pour into this place more crazily, and the United States soon became the largest gold producer in the world.