Most often when we think about exercise we think aerobic. That is in part because of the high energy classes available at most gyms. Aerobic exercise is not confined to those classes, however. For most people, low to moderate exercise or exertion is generally aerobic.
The biggest iron mine. The worlds biggest open pit iron mine can be found near Hibbing, Minnesota. At its maximum, the area covered by the Hull Rust open pit mine is five miles (8km) long, 2 miles (3,2km) wide and 535 feet (180m) deep. It looks like a man-made Grand Canyon of over 2,000 acres (8,1kmÂ²).
The Pebble Partnership believes a mine near Bristol Bay, Alaska, could produce up to 107.4 million ounces of gold. (AP) Using exploration drill rigs, The Pebble Partnership is currently analyzing what may be the largest undeveloped copper deposit in North America, located in southwest Alaska.