Underground
Category	Game Concepts
Built from	Mine
View	U key
Cube	10 ft
Ore view	8 + 0.16 × Mining tiles

Underground

Beneath every settlement lies solid rock, cut into a grid of 10 ft cubes and laced with ore veins. A Mine is the way down: each Mine owns its own tunnel network, starting from the shaft under its yard.

The Underground view

Press U to switch the town into the Underground view. The surface turns see-through, the rock becomes a grid, and every Mine entrance stays visible. Here you plan tunnels with the tunnel tools: Tunnel, Slope, Shaft, Room, Support, Scaffold and Erase, plus Auto-support. Page Up and Page Down step one layer up or down; with Room selected, Ctrl + Page Up / Page Down changes the room's height. Esc drops the current tool. Arrows on the panel step between your Mines, and the Close button returns to the surface.

Building a Mine

A Mine costs 3 Lumber, 1 Steel Ingot, takes 2 × 2 map cells and has up to 6 workers. Its shaft must stand away from water (5 tiles) and away from another Mine's tunnels, and not on ground higher than about 330 ft. Once a tunnel has been started the Mine can no longer be moved. Raising a Mine to level 10, 15 or 20 needs a Guild Hall of that level and that many Guild Members, as with walls. The first Mine you build finds a cube of Iron Ore right beside its shaft, 2 layers down. Around a new entrance, ore within 12 cubes and 12 layers down is plain stone.

How mining works

Every week the Mine's Miners dig the tunnels you planned, one worker per digging face. A miner's tool sets how much work he does in a week:

A plain rock cube takes 1.25 work at the surface layer and a little more the deeper it lies (+0.36% per layer down). Slopes cost ×1.25 and shafts ×1.5. Each rock cube gives 0.1875 Stone; fractions carry over from week to week. The farther the digging face is from the entrance, the slower the work, because everything must be hauled back: the first 16 cubes are free, and the haul factor never falls below 0.2. Three upgrades per Mine speed up hauling:

Mine Cleanup workers fill the Mine's remaining worker places after the Miners and each carry up to 25 units a week of ore, Stone and Jewels left on tunnel floors back to town stock, nearest the entrance first.

Ore sight

Ore hides in the rock until your tunnels come near it. Each time a tunnel cube is dug open, every ore cube within the ore view radius of it comes into view, above and below as well as to the sides, and stays on the map from then on. The radius grows with the hero’s Mining skill, and the town's Miners dig with the hero’s eye for ore too: radius = 8 tiles + 0.16 tiles per point of Mining (a tile is a 10 ft cube). Tools and lanterns add no range. When the hero’s Mining skill rises, the rock around every tunnel already dug is checked again at the bigger radius, so old tunnels can show new ore.

The grid of explored rock grows with your tunnels. Ore that a slope or shaft runs past is marked for extraction automatically: it is taken out without opening the cube, which becomes dead stone.

Ores

Each ore cube holds 8 to 47 units; rarer ores lean toward the high end. Gold ore also gives 0.25 Jewel per unit dug. Ores need a Guild Hall level (and as many Guild Members) before they can be dug, and a minimum tool:

Dig speed multiplies the tool's weekly work, so Platinum is dug at one sixth the speed of Iron.

Dangers

Each week an open tunnel cube that is not supported has a 0.25% chance to collapse into rubble. A timber support costs 0.25 Lumber per cube and stops collapses; Auto-support, on for new Mines, supports every finished cube. Miners cut off by a collapse are trapped; they survive 2 weeks and are freed when their tunnel reconnects to the entrance. A Cave-in disaster brings down 12 more unsupported cubes at the next week, while an Avalanche fills the first 8 cubes in from the entrance, supports or not.

Heroes underground

A hero can climb down a Mine's shaft and dig by hand. Keys 1 to 7 choose straight, slope down, slope up, shaft down, shaft up and two more digging modes, and the arrow keys climb shafts. Each swing is one twentieth of a townsperson's week with the hero's best tool. The hero's weekly limit is that tool's week × (1 + Mining skill ÷ 100), and each swing may raise Mining (see Skills). What doesn't fit in the bag is left on a pile.

Buildings underground

Town buildings can be built in dug-out rooms. They take no town cells, have 3.0 m storeys and no roofs, never collapse, and disasters never touch them. Workers walk to them from the nearest Houses along the roads and down through the Mine.

See also

All Game Concepts scrolls