Excavation is the act of breaking through a wall into unmapped space. Any tile adjacent to the player's current position that is not already a room can be excavated, given a pickaxe. The wall must be chipped away over multiple strikes before it yields. Each strike consumes an action point, costs stamina, reduces the pickaxe's durability, and may produce a mineral as a side effect. When the wall's durability reaches zero, a new room is created at that position.
Excavation is how a seeker extends the dungeon beyond what was generated for them. It is a tool, stamina, and time investment — a commitment to a direction the dungeon did not already go. The new room produced is a bare location, discovered and active, but otherwise empty of the content that placed rooms carry.
Vein mining is a location-action at specific card types — a river bank, a narrow passage, or a rocky wall already in the dungeon grid. These locations offer a mining action directly: given a pickaxe, the seeker can attempt the action and receive a yield from the location's loot pool. No wall is broken. No room is created. The location simply produces something from its interior.
Vein mining is faster and safer than excavation — it does not risk a ceiling collapse, and each action is a single attempt rather than a sustained project. The tradeoff is that vein locations are placed by the dungeon, not by the player. They are found, not made. Yield chance and loot pool are defined by the location type.
Every wall begins with 100 durability. The seeker chips away at it over multiple turns until the wall falls and a new room opens behind it.
Excavation cannot begin without a pickaxe that is currently equipped and has durability remaining. The pickaxe is the only tool that reduces wall durability. Without one — or with a broken one — the command does nothing and the wall does not move. A pickaxe that breaks mid-excavation must be replaced before the work can continue.
Each excavation strike reduces the wall's durability by the seeker's effective strength: the pickaxe's own strength added to the seeker's base strength stat. The Miner perk increases this combined value by an additional 25%. A seeker with high strength and the Miner perk can complete an excavation in significantly fewer strikes than one relying on a bare tool.
When wall durability reaches zero or below, the excavation is resolved in a single event: the wall is cleared, a new empty room is placed at that map position, and the seeker is notified that the tunnel is complete. The room is fully accessible from that point forward and connects normally to adjacent rooms that exist. It will not be populated with cards the way dungeon-generated rooms are — it is a blank space the seeker has carved out of the world.
Every strike during an in-progress excavation has a chance to produce a mineral. The wall resists you, but it also reveals what it contains.
Each excavation strike that does not complete the wall rolls a 20% chance to produce a mineral. On a success, the game selects a card from the pool of ore and gem items — filtered to cards that have not exceeded a random rarity threshold set by a separate die, and that belong to the base dungeon pool. The selected mineral goes directly into the seeker's equipment, and the log records what was found.
Thirty percent of the time, regardless of what would have been selected, the result is replaced with plain stone. Stone is the most common return from excavation and is always possible even when richer ore is in range.
The Prospector perk adds a second, independent roll on every excavation strike: a 5% chance to produce a gem regardless of whether the primary mineral drop succeeded. The gem is drawn from the same gem pool as the primary drop — filtered to base-deck gem cards — but is an entirely separate event. A seeker can receive both a primary mineral and a Prospector gem from a single strike.
Both minerals, if both drop, go into the seeker's equipment simultaneously. The log records each find individually. A strike that produces nothing, a strike that produces stone, and a strike that produces a named gem are all possible outcomes of the same action.
Every mineral produced by excavation has its quality applied before it enters the seeker's inventory. Quality is not determined by the excavation itself but by the standard quality roll the game uses for all yielded items. A seeker may find dismal ore or masterful ore from the same wall — the quality range is the same as for any other item source in the dungeon.
Certain location cards — marked graveyards and burial sites — support a separate digging action with a shovel rather than a pickaxe. Grave digging uses the same general structure as excavation but draws from a distinct loot pool appropriate to its location type: remains, relics, and items associated with what was buried. The Grave Digger perk adds a 1% chance to find magical items during any mining or digging action.
Performing mining actions — both excavation strikes and vein mining — advances the mining proficiency. Proficiency is a value that grows through use rather than being unlocked at a threshold. Higher mining proficiency improves outcomes over time: at advanced levels it affects yield chance, the rarity ceiling on available drops, and the efficiency of excavation work. Proficiency is carried across the run and accumulates regardless of which location the mining occurred in.
Mining is not free. Every strike taxes the seeker's equipment, stamina, and occasionally the structural integrity of the room itself.
Every excavation strike reduces the equipped pickaxe's durability by one, regardless of how much wall durability was removed. A pickaxe that hits zero durability breaks. A broken pickaxe is unequipped automatically and can no longer be used to excavate. If the pickaxe breaks mid-excavation, the in-progress wall is not lost — its accumulated damage remains, and work can resume once a replacement pickaxe is found and equipped.
Each excavation strike costs stamina equal to the pickaxe's stamina cost value. Stamina that falls to zero is floored there — it does not go negative — but a seeker with no stamina cannot run and may face reduced action options depending on their other stats. Mining in an area with no stamina recovery available is a decision that becomes more costly the longer the excavation takes.
Every in-progress excavation strike (not vein mining, not completion strikes) rolls a 10% chance of triggering a ceiling collapse event. The collapse fires a dungeon event — falling debris, structural disturbance — with its own consequences for the seeker's health and position. The Mole Man perk sets this chance to exactly zero: with it, no excavation strike can ever trigger a collapse. Without it, every strike is a small gamble on the structural stability of the rock above.
Some locations carry exposed mineral deposits that can be worked directly — no excavation required, no new room produced. The location itself is the resource.
A location that supports vein mining presents a mining action when the player enters it, provided a pickaxe is equipped. The action costs one action point and rolls against a fixed chance — typically around 33% for a standard mineral vein. On success, one card from the vein's loot pool enters the seeker's inventory. On failure, the turn passes with nothing produced but no durability or stamina cost from the attempt itself beyond the action point.
Different location types carry different vein pools. A river bank with exposed rock yields the same mineral categories as a narrow underground passage, but grave sites yield bones, relics, and burial goods. The location's type determines not just what can be found but at what rarity. A seeker who knows which locations carry which veins can plan routes through the dungeon with resource gathering in mind.
Vein mining is a repeatable action. The same location can be mined on successive turns as long as the seeker remains there and retains action points. Vein locations do not deplete. A 33% chance per action means repeated attempts are not guaranteed to be productive. Time spent mining a vein is time not spent elsewhere, and some runs will reward patience at a vein while others will reward moving on.