The default assumption should be that a casino is showing you a lower RTP build of a slot unless it tells you otherwise. InOut Games ships Mine Slot with multiple configurable RTP settings, and operators choose which one to deploy. Open the in-game info panel before your first spin and confirm the number. If it's missing, that's a flag.
RTP version actually loaded
Two casinos can both "offer Mine Slot" and serve materially different math. A 96%+ build over 1,000 spins behaves very differently from a 92% build. Ask support in writing if the info panel doesn't say.
Licence and dispute path
An MGA, UKGC, Gibraltar, Isle of Man, or Kahnawake licence gives you somewhere to file a complaint that isn't the casino's own inbox. Curaçao licences vary; the new GCB framework is stricter than the legacy sub-licence model, but enforcement is still uneven.
Bonus terms versus a low-volume game
Mine Slot is not a 50-payline grinder. If a welcome bonus carries 40x wagering with a €5 max bet and only counts slots at 100%, that's workable. If it caps wins from bonus funds at 5x the deposit, that's the kind of fine print that quietly neutralises the offer. Read the cashout cap before the wagering ratio.
Game availability and demo access
Confirm the title is in the live lobby, not just the marketing list. Try the Mine Slot free demo first to verify the build matches what you expect before funding an account.