Valuable minerals from the ore are separated by the combination of water and mechanical action. The small pieces of ore bearing the valuable minerals pass through the screen and are concentrated further in sluices. The larger ones (those that do not pass through the screen) are moved to a waste stack using a conveyor. Trading in GETFs involves payment of commission and storage fee (charged on an annual basis). The expenses incurred in relation to the handling of the fund are charged through the selling of a certain amount of the gold as represented by the certificate. Over time, the amount of gold in the certificate, as may be expected, decreases. Largest Gold Nuggets Discovered: Welcome Stranger And Hand Of Faith Gold nuggets are naturally occurring large masses of native gold found in alluvial deposits. Often they are concentrated by watercourses and recovered by placer mining. In other instances, gold nuggets are found in piles of residue in sites where mining operations once took place. The lines, which represent equilibrium for the concentration, are drawn for ions at unit activity. Other concentrations may be represented by additional lines. The voltage potential is represented by a vertical axis, which is labeled Eh, where "h" stands for hydrogen. Physics has an even more strict definition for noble metals. Minting coins, whether gold or silver, always entails the risk of having the value of the metal used in the coin greater than the coin's face value. This is especially true in coins of low denomination. Because of this, there exists the possibility of some smelters taking gold or silver coins and melting these down for the scrap value of the precious metals. Ruthenium - Karl Karlovich Klaus, a Russian chemist and naturalist, is usually credited with the discovery of ruthenium (in 1844). He discovered it from platinum ore samples he obtained from the Ural Mountains in Russia. He named this precious metal after "ruthenia", the Latin word for Klaus's home country Russia.