Mine Works

The shafts, galleries and spoil heaps of a mine, working or abandoned. Timber props hold up the roof, ladders go down into the dark and the air grows warm and bad the deeper one goes. Miners fear the roof, the gas and the water more than any monster, and they are usually right.

Light
Dark
Going
Hard

Hear it

Hazards

  • Roof fall. A prop gives with a crack and a section of roof comes down in a roar of rock and dust. D&D 5e: Each creature under the falling section makes a DC 13 Dexterity save, taking 2d10 Bludgeoning damage on a failure or half on a success, and the rubble becomes Difficult Terrain. A Search action and a DC 11 Wisdom (Perception) check notice the weak props and cracked roof first. Stronger: 4d10 and DC 15 (levels 5 to 10), 10d10 and DC 17 (11 to 16), 18d10 and DC 19 (17 to 20). In an abandoned mine, the GM may set it off with a careless blow instead of a trip wire.
  • Black damp. In old galleries the air has no life left in it. Lamps die first, then people. D&D 5e: Where the air is unbreathable, a creature can hold its breath for 1 plus its Constitution modifier minutes (at least 30 seconds). After that it gains 1 Exhaustion level at the end of each of its turns, and loses all of them as soon as it can breathe again. A lamp going out is the warning.
  • Firedamp. A gas with no smell gathers under the roof of coal and shale galleries. A spark is enough. D&D 5e (House rule): Our rule: when an open flame or a spark meets firedamp, it explodes. Each creature within 6 m (20 ft) makes a DC 14 Dexterity save, taking 4d6 Fire damage on a failure or half on a success, and the blast may bring down the roof (see Roof fall). Nature DC 13, or a canary that falls silent, warns of it.
  • Open shaft. Rotten ladders and old shafts with no cover drop straight into the dark. D&D 5e: A falling creature takes 1d6 Bludgeoning damage for every 3 m (10 ft) it falls, up to 20d6, and lands Prone unless it took no damage. A flooded sump at the bottom lets it try a DC 15 Strength (Athletics) or Dexterity (Acrobatics) check as a Reaction to halve the damage.
  • Flooded gallery. When the pumps stop, the deep galleries fill with cold, black water. D&D 5e (House rule): Our rule: wading through water waist deep is Difficult Terrain. Swimming a fully flooded stretch needs the breath rules of the SRD's Suffocation and a DC 12 Strength (Athletics) check per 9 m (30 ft); a failure costs a round of breath without progress.

Adventure hooks

  1. The canary in the lower gallery died this morning, and the foreman is sending the men down anyway because the owner has a contract to fill. One miner’s wife wants someone to go down first.
  2. An abandoned mine still has its richest vein in the walls, beyond a flooded gallery. The widow of the last owner holds the old plans and wants a third, and her late husband’s debts are attached to the plans.
  3. Miners hear knocking behind a wall where nobody has dug. Some say it is the little folk warning them; others say it is the men lost in last year’s collapse, and they knock in the old signal code.
  4. The lift cage goes up and down on its own at night. The winding man swears he has nothing to do with it, and his breath smells of the owner’s brandy.

What may happen

  1. A vein of bright ore in the gallery wall, left behind when the miners fled.
  2. Knocking in the rock, three blows and a pause, over and over. Miners say it is the trapped calling for help.
  3. Picks, a lunch pail, a lamp still half full of oil. The miners left in the middle of a shift.
  4. An ore cart rolls out of the dark by itself, slows, and stops at the party's feet.
  5. A canary in a cage hangs from a prop. It is alive, and singing.
  6. The newest gallery breaks into a natural cave that is not on any plan. Something has come through.
  7. The foreman wants the mine cleared so work can start again, and he will not say what drove his men out.
  8. The props groan as the party passes, and fine dust falls like flour.
  9. Tally marks on the wall of a dead end, and the name of a miner. The last mark is two months old.
  10. Warm water runs from a crack and leaves a crust of bright crystals.
  11. The lift cage hangs halfway down the shaft. The winch above has been cut.
  12. Small boot prints in the dust, too small for a man. Someone else works this mine at night.

Creatures

Other sites

Dungeon, Crypt, Graveyard, Ruin, Sewer, Fortress, Temple, Laboratory, City

This work includes material from the System Reference Document 5.2.1 ("SRD 5.2.1") by Wizards of the Coast LLC, available at https://www.dndbeyond.com/srd. The SRD 5.2.1 is licensed under the Creative Commons Attribution 4.0 International License, available at https://creativecommons.org/licenses/by/4.0/legalcode.

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