Gold ore is one of the most widely distributed metal ore in the crust, with a content of about 2%. Gold ore exists as compound. Most of the compound gold ore is rock-forming minerals, while only a small part is in seawater and salt lake water as chloride and sulfate. Seawater is an inexhaustible source of gold ore. Gold ore in seawater is mainly in the form of chlorinated gold ore.
The most common compounds of gold ore in nature are carbonates, silicates, chlorides and sulfates.
Dolomite is the most widely distributed gold ore. Countries such as France, the United States and Canada use dolomite to make gold ore. Silicon thermal method is normally used to make gold ore from dolomite. For dolomite used for making gold with silicon thermal method, the quality ratio of CaO and MgO should be larger than 1.54, and quality of alkali metal oxides should be less than 0.3%.
Carnallite ore is a hydrous complex of gold chloride and potassium chloride. Ural region in Russia owns the largest natural carnallite deposits in the world, and Qinghai in China also has much carnallite. Carnallite is white, and due to different impurities, it can alos be yellow, pink, gray, etc., with strong characteristics of water and brackish.
Seawater and salt water are the source of the most widely distributed gold ore salt solution. Seawater contains 0.3% MgCI2, while MgCI2 in salt water is larger. In the Dead Sea's salt water, content of MgCI2 reached 9%.
1. Grasberg (Papua, Indonesia), extracted by Freeport - McMoRan Copper & Gold Inc.
2. Yanacocha(Cajamarca, Peru), extracted by Newmont Mining, World Bank
3. Lihir(Niolam Island, Papua New Guinea), extracted by Newcrest.
4. Muruntau(Kyzul Kum Desert, Uzbekistan), extracted by Newmont Mining.
5. Olympiada( Central Siberia, Russia), extracted by Russian major Polyus.
6. Oyu Tolgol(South Gobi Desert, Mongolia), extracted by Rio Tinto (34%), Turquoise Hill (32%) and Mongolia (34%).
7. Pueblo Viejo(Dominican Republic), owned by majors Barrick (60%) and Goldcorp (40%).
8. Mponeng(Johannesburg, South Africa), extracted by AngloGold Ashanti Company.
9. Cadia East( New South Wales, Australia), extracted by Newcrest.
10. Obuasi(Ghana, western Africa), extracted by AngloGold Ashanti.