Coral polyps also use the energy supplied by their symbiotic algae to produce calcium carbonate, or limestone. They secrete the limestone from their base, creating a protective skeleton and a hollow chamber called a cup. The polyps retreat into their cup to hide when predators come looking for them.
Uranium is mined where there are concentrations in the earthâs crust. More than half of the worldâs uranium comes from mines in Canada, Australia and Kazakhstan.Other major producers are the United States, South Africa, Namibia, Brazil, Niger and Russia.Many more countries have smaller deposits that could be mined if needed.ore than half of the worldâs uranium comes from mines in Canada, Australia and Kazakhstan. Other major producers are the United States, South Africa, Namibia, Brazil, Niger and Russia. Many more countries have smaller deposits that could be mined if needed.
Rossing uranium mine, located near the town of Arandis in the Erongo Region of Namibia, is the sixth largest uranium producing mine. The open-pit mine produced 2,289t of uranium in 2012. Operating since 1976, Rossing is the first uranium mine in Namibia and one of the oldest in the world.