The Trade Octagon is used primarily by the Consortium, a collection of the eight largest mining companies in Keldagrim. It is here that they conduct nearly all of their trades between each other, selling things such as labour, ore, metal bars, and even mine access.
The Trade Octagon, as its name suggests, is shaped like a large octagon. Each company receives one side of the Octagon, where they position two traders to buy and sell goods. The flow of goods, which would quickly go out of control without being carefully monitored, is watched over by the Trade Referee. Without a referee, the Trade Octagon would be unable to function.
There was a leak in which an activity icon was put on the mini-map in the Trade Octagon. It was quickly removed, but a Jagex Moderator confirmed that there was an activity planned for the area. The moderator said it kept getting pushed to the bottom of his pile of work, but it was recently confirmed that the activity has been permanently scrapped. Instead, players can now pickpocket the traders at level 90 Thieving.