Gol Gohar mine

Iron ore has been mined at Gol Gohar for an estimated 900 years; a large underground mine and smaller open-pit mine in the center of the area used to exist as traces of historical mining activity, but activity since the 20th century has mostly erased these traces.[5]^: 105 An estimated 350,000 tons of iron ore were extracted from the old mines at Gol Gohar over the course of their existence.[5]^: 105

In 1969, the Iran Barite Company began exploratory work at the Gol Gohar site; this was then delegated to the National Iranian Steel Industries Co. (or NISIC), a government corporation that now operates under the name National Iran Steel Company.[5]^: 105 NISIC then entered into a joint venture with the Swedish company Granges International Mining to continue exploring the deposits.[5]^: 105 Exploratory drillings began in 1975 on 6 different areas, and mining activity began in 1994.[5]^: 105

The Gol Gohar complex is located in a depression known locally as the Kheyrabad Salt Lake, which itself is located on the northeastern margin of the Sanandaj-Sirjan tectonic-metamorphic belt.[5]^: 106 The underlying basement rock consists of Paleozoic metamorphic rocks;[5]^: 106 mainly gneiss, mica schist, amphibiolites, quartz schist, marble, dolomite, and calcite.[4]^: 709 Above these are Mesozoic and Cenozoic sedimentary rocks and Quaternary alluvial deposits.[5]^: 106

The ore body itself is estimated to be lenticular in shape, about 2600 m long from east to west and about 400 m wide from north to south.[5]^: 106 Several different proposals have been put forward for how it originated: Ljung (1976) suggested a metasedimentary origin, Muke and Golestaneh (1982-91) proposed a magmatic origin similar to the Kiruna mine in Sweden, Hallaji (1992) argued in favor of a metasomatic origin, and Khalili (1993) proposed a volcanic sedimentary origin.[5]^: 106