Mining has been practiced in Taiwan for hundreds of years. Sulfur was an early important resource collected on the island. Coal mining expanded in the 19th century to keep up with demand from increased foreign trade. Heavy industry was further expanded under Japanese rule, but air raids towards the end of World War II decimated mining infrastructure, falling below 19th century production levels. Copper mining expanded in the mid-20th century, but ended in the 1980s following a global collapse in the price of copper.