There are two ways to remove coal from the ground: surface mining and underground mining. Surface mining is used when a coal seam is relatively close to the surface, usually within 200 feet. The first step in surface mining is to remove and store the soil and rock covering the coal (called the overburden).
Pearl oysters are not closely related to true oysters, being members of a distinct family, the feathered oysters (Pteriidae). Both cultured pearls and natural pearls can be extracted from pearl oysters, though other molluscs, such as the freshwater mussels, also yield pearls of commercial value.
Many types of seafood are high in iron. Oysters are particularly iron-rich -- a 3-ounce portion of wild eastern oysters supplies 8 milligrams. Mussels, octopus, sardines, clams and crab typically provide anywhere from 2 to 6 milligrams of iron per serving, while most varieties of fish contain less.