Do there use a broker service or deal direct with the buyer. Also do they find it difficult to find buyer from overseas?

As far as l am aware all Coal mines are on long time contracts mostly with Japan and China.
They only deal in millions of tons, l tried to buy a one off 100,000 ton shipload and they laughed at it.
You can deal direct with these companies, they sell both direct and to suppliers who then on sell to other customers.