Please let me elaborate on the question.
Suppose you had a coal mine in the possession of a worker co-op. The members of the co-op make their living from the produce of this coal mine.
Nobody can tell the co-op what to do with their mine, ex hypothesi. Furthermore, they can't decide to stop up the mine and prevent anyone else from exploiting it, for as soon as they give up working possession of the mine they give up any property rights they had through their utilization of it, also ex hypothesi. Another co-op or group could therefore move in and begin to exploit the mine.
It would appear therefore that in the absence of a world-wide agreement on a moratorium on coal-mining - which, again ex hypothesi, no worker or group of workers would be bound by - the mine is doomed to be exploited, against the best interests of mankind and therefore the workers themselves.
So again I ask, in all sincerity, and with the utmost desire to see some form of social anarchism succeed: what precise mechanism would prevent exploitation of the world commons against the best interests of the commoners?