Because "Union Pacific Railroad coal sector" (Union Pacific Railroad Coal Department) hired laborers at lower wages, leading to white unemployment grudge.

In 1885 was 9 months 2 Day, Wyoming Rock Springs City 150 more than whites to "Knights of Labor" (Knights of Labor) in the name of carrying guns surrounded Chinatown for burning and looting, attacks on unarmed Chinese, namely 79 between Chinese houses were burned, 28 Chinese were killed and 15 people injured, 26 people died in the wolf fled into the mountains abdomen, hundreds of Chinese were off. This is a place in the atrocities committed in broad daylight, shocked the nation, the police immediately arrested 16 suspects, but because the Chinese could not testify in court, and finally, 16 were all acquitted.