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 open pit mine is very new and began production in January 2013. It also has large silver and copper reserves to complement its gold deposit. As it ramps up to full production, it will also be one of the largest producers in the world, but we'll save production figures for a separate Top 10 List.