Frostfire Mine is the event people prepare for as if it were an alliance war, and then wonder why their numbers feel wrong. Century Games' description explains both halves of that: it is solo, and a chunk of your stat sheet does not come with you.
The format, exactly as published
Frostfire Mine is a solo event that is available every two weeks. You can register and participate on the same day. There are 6 time slots, and all players with Furnace Lv. 16 or above are eligible.
Each player registers for one slot that has not started and is not locked. Registration opens 10 minutes before a time slot starts, and you are free to change your time slot. In practice: set an alarm ten minutes out, and do not treat your first pick as final — if your alliance decides to concentrate in a different slot, moving is free.
If the battlefield refuses to let you in, the official check is short: see whether you have troops deployed or scouting. Recall everything before your slot opens.
The buffs that stop working
This is the part that quietly ruins people's expectations. Century Games states that some stats — your position, your Gathering stats, and Marching Speed — are not available in Frostfire Mine.
So the two investments that feel most relevant to a mining event, gathering stats and march speed, do nothing. And if you hold a server position, its perks do not travel with you either — which levels the field far more than most players realise. A chief who reads that sentence and stops trying to out-march everyone will do better than one who does not.
Solo means solo
The word solo in the official description is doing a lot of work. Your alliance cannot reinforce you and you cannot rally, which means every fight is your own squad against another single squad. That makes composition matter more here than almost anywhere: per the Combat FAQ, Infantry hold the front row and Marksmen deal the highest single-target damage from the back, and with no ally garrison behind you there is nothing to cover a bad ratio.
Where to stand, and what we are not claiming
Community consensus — ours too, from playing it — is that contesting the Lv. 3 centre vein is usually worse value than holding a Lv. 1 or Lv. 2 vein you can actually keep, because uninterrupted lower-tier extraction beats being repeatedly knocked off a higher one. That is our judgement, not a published rule, and we mark it as such.
We also see "30 minutes" quoted as the event length everywhere. Century Games does not publish a duration in its English help centre, so we do not state one. And we would rather tell you that than invent a number.
Sources: What is Frostfire Mine — cadence, slots, Lv. 16 · Why can't I enter the battlefield · Which bonuses do not take effect in Frostfire Mine
Every rule above is Century Games' own wording from the official English help centre. Anything we added from play experience is labelled in the text.