How many tons of Gilsonite Iran and USA export to worldwide market?

Since American Gilsonite bankrupted and closed,most of buyer shift to Iran Gilsonite and started to procure the material from Iran market.Becuase of negative reports of American Gilsonite on Iran Gilsonite,most of buyers hesitate to even test it but step by step buyers unstrstood Iran quality is much higher than American and now they are  importing volume goods.

The picture is visit of American at Iran Gilsonite mines! 

American gilsonite

American Gilsonite exported annually 30000MT powder and supplied the same quanity to domestic market.It is very small quantity and since the production was too small size the price was even 10 times higher than Iran.

Iran Gilsonite 

Iran gilsonite exporters shipped more than 180000MT gilsonite in raw form which is called lump and powder in various mesh size.In the world Iran is number one exporter in good quality and price.

Now there is lack of supply in USA market and American came to Iran to buy material.Do you thinks they will come back to market again or due environmental issue and high cost of expoloration in America they will close the factory for ever?