There's different grades of coal, so seperation is there. That's why you see coal moving up and down the river different grades being utilized at different locations
You are also correct in that GLER does not have to own their own loading/shipping terminal but most (if not all) loading shipping terminals receive coal from various sources and it is sold from there stockpiles to other buyers. In this case GLER has a contract to provide to a specific end user so the coal would have to be completely separate from mining all the way to shipping. The shipping terminals I am aware of would not separate the coal this way. I'm not going to say it is impossible because I am not that certain but I will say it has significant difficulties in doing so.
Maybe I didn't fully understand your 'quote' (English is my 3th language) but is it possible (in the coal business) that the 'big foreigner company/ end user' provides/stand in for the storage of the coal...the Handling of Shipments etc.? Of course we don't know all the details yet.