Chemours is building a $150 million sodium cyanide plant in the Mexican state of Durango. The firm has produced the chemical, used to refine gold, since 1952 at a Memphis facility said to supply one-quarter of the world’s solid sodium cyanide. Although Chemours is not disclosing the size of the Mexican facility, the firm earlier said it plans to increase its mining chemicals capacity by 50%. Chemours says it chose the Durango location to be near the Mexican precious metals mining industry. In January, a joint venture of Evonik Industries and Grupo Idesa opened a cyanide plant in Coatzacoalcos, Mexico.