Native metal brass, bronze, pewter, German silver, osmiridium, electrum, white gold, and silver-mercury and gold-mercury amalgam. Only gold, silver, copper and the platinum metals occur in nature in large amounts. Over geological time scales, very few metals can resist natural weathering processes like oxidation, which is why generally only the less reactive metals such as gold and platinum are found as native metals. The others usually occur as isolated pockets where a natural chemical process reduces a common compound or ore of the metal, leaving the pure metal behind as small flakes or inclusions. Non-metallic elements occurring in the native state include
Mining in North Korea handle 10 million tons of zinc ore. Conventional flotation methods are adopted to extract lead and zinc concentrates. Other products from the mine are sphalerite, chalcopyrite, and galena. In gold alone the nation is estimated to hold around 2,000 metric tonnes of reserves, which at a gold value of $1,200/ounce, would give a total worth of $84.6 billion. Other available resources include iron, with 5 billion tonnes of 50% iron-content ore in reserve, nickel, with 36,000 tonnes of the pure metal, and zinc metal, with around 21,100,000 tonnes. The Daebong Mine, located on the border of Gapsan and Woonheung in