A trommel specifically consists of a rotating metal tube that is slightly tilted, with a screen at the discharge end. Attached to the inside part of the metal tube are lifter bars. Ore is fed into the trommel through its elevated end. Pressurized water is supplied to the tube and the screen sections. Also here are the Afrikaans and English versions of the name "South Africa", both inscribed in capital letters. On the reverse of the coin is an image of the springbok, an antelope specie which is a South African national symbol. Atop the image is an inscription of the name of the coin, in capital letters, while below it is the coin's gold content, inscribed in Afrikaans and English. Bullion: Mass Of Precious Metals Bullion is a mass of any one of the known precious metals. By strict definition, precious metals are those metallic elements that are rare. Bullion is commonly made of either gold or silver. Its value is determined by the worth of the metal rather than by its face value as money. While some accounts point to the year 1848 when gold was discovered in California, history tells us that this precious metal was already being used extensively by the ancient Egyptians, Romans, Greeks, Chinese, and South Americans. Throughout history, gold has served as a measure of value and a symbol of wealth. It is also considered one of the rarest precious metals. Palladium closely resembles its co-member in the platinum group - platinum. It is soft and is silvery-white in color. Like rhodium, palladium is largely used as a catalytic converter. As of January 2010, the price of this metal is estimated to be approximately USD424 per troy ounce (USD13,632 per kilogram). Silver: Precious Metal With The Highest Thermal And Electrical Conductivity Silver is generally described as a soft, white, lustrous metallic chemical element. It occurs naturally in its pure form, as an alloy with other metallic elements (especially gold), and in chlorargyrite and other minerals. As one of three coinage metals (the other two being copper and gold), silver is very malleable and ductile.