On nations, there should be more ways to make money, because mining gold exclusively does not favor everybody.
The problem with gold is that once someone has a carbonado furnace, they get 400% as much out put for the same amount of work as a new player only getting one.
Things like jobs would allow people to get money in other ways than mining.
For example, a hunter would get money for killing hostile mobs (that spawn naturally), a shipbuilder would get money for building movecraft vehicles, a butcher would get money for killing animals and cooking meat, a mercenary would get money for killing people.

You should only be able to switch jobs every 7 days, to prevent people from switching jobs to make money for every action they do.