The Upper Peninsula is rich in mineral deposits, including iron, copper, nickel and silver. Small amounts of gold have also been discovered and mined. In the 19th century, mining dominated the economy, and the UP became home to many isolated company towns. For many years, mines in the Keweenaw Peninsula were the world's largest producers of copper (see Copper mining in Michigan). The mines began declining as early as 1913, with most closing temporarily during the Great Depression. Mines reopened during World War II, but almost all quickly closed after the war ended. The last copper mine in the Copper Country was the White Pine mine, which closed in 1995. Marquette County sits along the Marquette Iron Range, which for many years sent out a significant portion of the iron ore mined in the United States. , Marquette County is home to one remaining iron ore mine and one nickel and copper mine.