Mining in Iran is underdeveloped, yet the country is one of the most important mineral producers in the world, ranked among 15 major mineral-rich countries, holding some 68 types of minerals, 37 billion tonnes of proven reserves and more than 57 billion tonnes of potential reserves worth $770 billion in 2014. Mineral production contributes only 0.6 per cent to the country’s GDP. Add other mining-related industries and this figure increases to just four per cent (2005). Many factors have contributed to this, namely lack of suitable infrastructure, legal barriers, exploration difficulties, and government control over all resources. The most important mines in Iran include coal, metallic minerals, sand and gravel, chemical minerals and salt.