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).
Historic open pit of the Haile Gold Mine, South Carolina. The photograph shown in figure 1 was taken about 1998, and it shows the open pit of the Haile. deposit of Lancaster County, South Carolina, which produced approximately 50 metric tons of gold. New and more recent drilling by Romarco Minerals Inc. has delineated an additional ~115 metric tons of gold (Au), bringing the estimate of the amount of contained gold in this one Slate Belt gold deposit to