Gilsonite Asphalt Grade deposited in Gilane Gharb, Iran have been known since 1940 and it is the only mineral Asphalt Grade deposits area in Iran. The deposits contain 80 to 97 % asphalt content and there is reserved between 200 to 300 million tons of natural Bitumen. It has been used mainly for road construction and maintenance however oil well drilling fluid to prevent lost circulation.
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