The mining industry is another example of an increasing-cost industry. Copper mines differ in the purity of their ore and the cost of extracting it. When the price of copper is relatively low, only low-cost mines operate. As the price of copper increases, mines with progressively higher extraction costs become profitable and are brought on line. Between 2001 and 2006, the price of copper increased from $1,300 to $7,000 per ton, and the industry moved upward along the long-run supply curve as high-cost mines started or resumed production.
A recent geological survey of Afghanistan found a significant deposit of copper at Aynak, just south of Kabul beneath an old al-Qaeda training camp. With a copper price of $7,000, it would be profitable to spend the $1 billion necessary to develop the site. But if the price of copper were to fall back to the level observed in 2001, the Aynak mine would be a losing proposition.