There are roughly 20 ores in all in the mine, and that is it. The current respawn time for each ore is, I will admit, rather long at 14 hours unfortunately. This is meant to keep iron rare and prevent a sudden influx into the economy, though we plan on changing this system in the future. We are aware that the current system is rather dull and is full of downsides, but we plan on changing to a much more effective system with the arrival of the professions plugin! More details will be given in the future.
To prevent a sudden influx into the economy, I'm sorry but there is already tons of IRon into the economy, I mean at Freema5's shop in Malinor he had 1000+ Iron ingots in the beginning of its opening and now Its around 200 Iron ingots, So I don't think this would bring an IRon influx because I know Freema5 wasn't the only one that had lots of Iron from idk where.