To the west of Ethiopia near the Sudanese border lies a place called the Asosa zone. This may be the location of the oldest gold mine in the world. Dating back some 6,000 years, it provided a key source of gold to the ancient Egyptian empire, whose great wealth was famous throughout the known world. It may even have supplied the Queen of Sheba with her lavish gifts of gold when she visited King Solomon of Israel almost 3,000 years ago. The excitement in this part of the world is more about the future, however. Some local inhabitants already make...