Mercury and the Making of California

Gold and silver could not be refined without mercury; therefore, its production and use were vital to securing power and wealth in the West. The first industrialized mining in California, mercury mining had its own particular organization, structure, and built environments. These were formed within the Spanish Empire, subsequently transformed by British imperial ambitions, and eventually manipulated by American bankers and investors. In California mercury mining also depended on a workforce differentiated by race and ethnicity. The landscapes of work and camp and the relations among the many groups involved in the industry—Mexicans, Chileans, Spanish, English, Irish, Cornish, American, and Chinese—form a crucial chapter in the complex history of race and ethnicity in the American West. 
https://muse.jhu.edu/books/9781607322436