Mine Blown™

Mine Blown™ by Netent is a five-reel, three-row video slot set deep inside a rugged mine shaft, with ten fixed paylines and a gritty mining theme complete with tools, gems, lanterns and dynamite. The base game includes special Dynamite and TNT symbols: Dynamite randomly lands and turns itself plus nearby symbols into Wilds, while TNT likewise explodes to convert itself and adjacent symbols into Wilds. There are two distinct bonus features. The Free Spins feature is triggered when two Trigger symbols land on reels 1 and 3 plus a Free Spins symbol on reel 5; you receive ten free spins during which any Wilds that land become locked in place (sticky), and additional Free Spins symbols on reel 5 award three extra spins. The Bonus Spins mode is activated with the same Trigger pair plus a Bonus symbol on reel 5; this opens a Hold-and-Win style game where a mine cart with a base multiplier collects Vein symbols—Gold, Sapphire, Emerald, Ruby, Diamond—each adding multiplier value and sometimes extra spins. There is a Feature Buy option: players can purchase entry into the Free Spins for 25× their bet, or into Bonus Spins for 50× their bet. The game has a very high upper win potential, reaching up to 20,000× the stake when the bonus features align.

You can play it for real money.