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Inspiring Terrains: Underground Mines (Part 2 of 5)

copper mine“Inspiring Terrains” looks at encounters—fundamental building blocks that bring together PCs, conflict, and environment. With a little inspiration and a few mechanical bits, it’s easy to make the terrain in an encounter just as memorable as the foes. [Part 1]

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Deep, Foreboding Mines

Mines have been part of fantasy literature since its earliest days. In the game, though, mines usually feel like little more than renamed dungeons or caves—just another dark, underground environment with a different name…

Real mines—and memorable mines in the game—have an essential nature all their own. Unlike a cave, someone labored to excavate a mine. Unlike a dungeon, desire for a particular ore drove the creator of a mine to wrest stone from the ground. Because of this purposeful, profit-driven construction, mines share several defining characteristics, reflected in the terrain powers below. (Also remember that mines may invoke more familiar aspects of the rules—tight passages require squeezing, the pitch blackness makes light sources vital, and so on.)

Scrape the Walls (At-Will Terrain)

Twisting, Cramped Tunnels. Miners scrape away rock with their arms and carry it out on their backs. They follow the ore as it meanders through the surrounding stone. No one bothers with luxuries such as straight, wide, or high passageways. Instead, cramped mine tunnels corkscrew erratically, and miners quickly learn to mind their heads.

Overhanging rocks and sharp corners threaten any creature moving near this surface.

Free Action
Requirement
You must use a power that forces an enemy to move from, to, or through a square adjacent to a wall
Check
Perception check (easy DC) to notice where the walls, ceiling, and floor protrude dangerously
Success
The enemies undergoing forced movement take damage from its rough passage
Target Each enemy undergoing forced movement
Attack
Level + 3 vs. AC
Hit
1d4 + 1/2 level damage

Tenuous Support (Single-Use Terrain)

Holding Up the Earth. Tons of rock push down on the holes excavated by miners. Beams and bolts can hold back the patient weight of the earth for a time, but eventually the ground reclaims all mines, collapsing them into impassability.

Fine cracks in the rock and loose debris on the floor tell your trained eye that stress is building within the rock. A well-placed blow to the supports will bring heavy rocks crashing down.

Standard Action
Requirement
You must be adjacent to a wall that is held up artificially (by beams, rock bolts, or the like)
Check
Dungeoneering check (moderate DC) to collapse the wall
Success
Rocks fall from the wall as it collapses
Target
Each creature in a close blast 2 in the direction the wall fell
Attack
Level + 3 vs. Reflex
Hit
1d6 + 1/2 level damage, and the target is immobilized (save ends)
Miss
Half damage
Effect
The area of the blast becomes difficult terrain while the rest of the collapsing wall remains in place

Blinding Debris (At-Will Terrain)

The Dust of Toil. Endless chipping and blasting has left the mine covered in a thick layer of gritty dust. Dirt covers the skin, infiltrates packs and armor, and even invades the lungs, giving everyone a dry, hacking cough.

The dust is so sharp and gritty that it feels like tiny knives scraping throats and eyes.

Move Action
Requirement
You must be in a square covered in dust (in a mine, every square meets this requirement)
Check
Thievery check (moderate DC) to gather a handful of dust and fling it at your foes
Success
Blinding dirt flies in the face of one foe
Target
One adjacent creature
Attack
Level + 3 vs. Fortitude
Hit
1d6 + 1/2 level damage, and the target is blinded until the beginning of its next turn
Miss
Half damage

Caustic Crystals (Single-Use Terrain)

Dug from the Earth. Long sequestered from air and water, many ores corrode unexposed skin or emit dangerous gasses once unearthed. Miners avoid these natural dangers when they can, while canny creatures use them against their foes.

Ochre and vermillion ores eat away at unprotected living tissue.

Move Action
Requirement
You must be in a square containing exposed corrosive ore
Check
Athletics check (moderate DC) to kick or throw the ore at the intended target
Success
Corrosive rock strikes the targeted creature
Target
One adjacent creature
Attack
Level + 3 vs. Fortitude
Hit
1d8 + 1/2 level acid damage and 5 ongoing acid damage (save ends); if the damage roll is 8, the target is weakened until the end of its next turn
Miss
Half damage with no ongoing damage

Explosive Vapors (Single-Use Terrain)

A familiar smell betrays the presence of flammable gas, ready to ignite if exposed to searing flame.

Free Action
Requirement
You must make an attack that deals fire damage in a square containing explosive vapors
Check
The attack must inflict fire damage, although it need not hit
Success
Flammable vapors ignite in a fierce explosion
Target
Each creature in a close burst 3
Attack
Level + 3 vs. Reflex
Hit
1d8 + 1/2 level damage, and 5 ongoing fire damage (save ends)
Miss
Half damage with no ongoing damage

(The GM may wish to extend the explosion to the entire area filled by the vapors. This has the potential to be a devastating effect on the combat; be sure to mark the affected area before the battle and let intelligent creatures avoid setting off the explosion inadvertently.)

Tunnel Rat (Terrain Mastery Boon)

Use this boon to reward a player after a series of encounters in an underground mine.

Your long experience in the cramped quarters of deep mines lets you contort your body. Now you pass easily through areas others find constraining.

Lvl 8                       3,400 gp
Terrain Mastery Boon
Property You treat difficult terrain as if it were normal terrain
Power (minor; daily)
You can squeeze through spaces without the normal penalties to speed and attack rolls, without provoking attacks of opportunity, and without granting combat advantage.

Cramped, dark, twisting, dangerous—adventure awaits in the mines!

3 Replies to "Inspiring Terrains: Underground Mines (Part 2 of 5)"

Sersa V

May 5, 2010 at 1:18am

I. Love. This. Series. :)

What’s the duration on /tunnel rat/’s daily power?

noctambulist

May 5, 2010 at 8:50am

Good stuff. You’ve inspired me to work a mine into my next adventure.

Agree with Sersa, I love this series.

Mike Furlanetto

May 6, 2010 at 7:25pm

I’m glad you’re both enjoying the series. :)

Sersa V, I’d say that /Tunnel Rat/ should last until the beginning of the next turn in heroic tier and until the end of the encounter in paragon or epic tier. These terrain mastery boons are all swingy, though – their value really depends on the adventures’ terrain – so having it last until the beginning of the next turn at all tiers would work for some campaigns and letting it last the whole encounter would be well-balanced for others.

Good catch, though – I should have included that information.