Diggin' Up The World

[tog]

Is there anywhere in OD&D that I can find a reference for rates of tunneling?

[oakesspalding]

No. But "Any tunneling must be supervised by an Engineer" (U&WA, p. 22).

[talysman]

You could give players a chance they have an engineer background, maybe % chance equal to Intelligence? Dwarves, of course, should automatically be engineers.

Quick and dirty ruling, without research: feet per hour equals Strength score, maybe double or triple for dwarves. Hard rock halves rate, packed earth doubles rate but definitely requires timbers for shoring up tunnel every ten feet.

[krusader74]

You need to consider the location: Are you tunneling through clay, sand or rocks? You also need to consider what type of tools you are using: shovel, hammer/chisel, explosives? There's some interesting info here.

Dasharath Manjhi spent 22 years using a hammer-and-chisel to "cut a 120m-long, 10m-wide and 8m-high passage" through a mountain by himself "so that villagers could reach a local hospital," according to this source.


Using modern excavation equipment, "Norway's 15.23 mile long Laerdal Tunnel built during a five-year period from 1995-2000 at a cost of approximately $113 million U.S. dollars." Those stats as well as those for some other modern tunnels may be found here.

You also need to consider hazards: hitting ground water that can flood your tunnel; poison gas; cave-ins and collapses.

In a magical campaign consider using giant ants or dire moles to dig for you...

In the real world, a brood of 200 ants can dig a maze in as few as 3 days. Considered as a graph, this maze would have 60±20 vertices and 70±31 edges. You can get more details including statistics on tunnel volume, width, length, and so on in this research paper -- Nest excavation in ants: group size effects on the sizeand structure of tunneling networks -- but be sure to scale up!

In the real world, "Moles are fast diggers and can tunnel at a rate of 15 feet per hour. In favorable areas, shallow tunnels can be built at a rate of 12 inches per minute," according to this source. The very first issue of The Fantastic Four introduced the Mole-Man, a super-villain who used an army of giant moloids to dig tunnels for him. The Fantastic Four's Human Torch was able to tunnel by making himself hot as lava and melting his way through even rocky and mountainous terrain.

[waysoftheearth]

There's a brief summary of mines/counter-mines in Chainmail (p23) but as far as I can tell it doesn't talk about mining rates, only distances.

On p38 it adds that: Dwarves dig twice as fast as an equal number of human sappers. And on p39 it adds that: Orcs dig 1½ times as fast; one more mine or counter-mine.

OD&D includes a move earth spell, which moves earth at a rate of 6". Earth elementals likewise move 6", presumably through earth. Purple worms also move at 6", presumably including tunneling.

So all "normal" tunneling would have to be inferior to these rates?

Perhaps dwarfs 1", Orcs 2/3" and Men 1/2" (in "ideal" conditions)? Although that would be "fantastically" fast

[tog]

Two points:

This post from the blog Dyvers got me to thinking about PCs grabbing pickaxes and making their own routes through the dungeon. BUT as usual I misremembered and there are no rules/tables for mining rates!

Secondly, I'm greatly amused by the Greyhawk Construction Company, Ltd. and wish to hire their services in the future, which brings up the question of how quickly new areas can be excavated, though if I go the Mystic Underworld route I suppose it can be effectively instantaneous.

And 'way too much Minecraft and Nethack. I blame them.

[Merctime]

Just a quick thought... Wasn't there something along these lines in the Judge's Guild Ready Ref Sheets?

[waysoftheearth]

Great memory Merctime!

Yes, Ready Ref Sheets v1 (p18) has a table for PITS & TUNNELING, giving the number of Men required to tunnel through 20ft of earth (or 10ft of stone) per day.

It suggests that a crew of 10 men (or 5 dwarfs) can dig an 8ft high x 3ft wide x 20ft long tunnel through earth each day. It also suggests that the above tunnel would (minimally) require 2gp worth of wooden reinforcements to be viable.

[coffee]

Jul 30, 2014 8:10:32 GMT -6 tog said:

This post from the blog Dyvers got me to thinking about PCs grabbing pickaxes and making their own routes through the dungeon. BUT as usual I misremembered and there are no rules/tables for mining rates!

Reminds me of a guy I knew back in the 80s. We got to a point where we couldn't proceed directly, but wanted to outflank a guardpost in the dungeon.

He got out the scroll he had, with seven Disintegrate spells on it, and made his own passage...

Good times.

[Finarvyn]

Totally off topic here, but this conversation makes me think about standard dungeon hallway dimensions. If you're slowly chipping your way underground, why make 10' wide hallways? I'd think that 3' to 5' would be a lot more realistic. I'm sitting in a bedroom typing on my computer, and the width of this room is around 10' or 11' and I'm trying to imagine someone digging something of this size ... just seems pretty huge, that's all.

I wonder what passage widths were like for pyramids or for coal mines.

[coffee]

For coal mines, you need to get the coal out. So your passages will be wider than one might think. If you have mine carts, you'll need the track for them to run on, and you'll want to have elbow room beside that.

And once you're up at the face, or in a rich seam, you'll excavate all the coal that's there, so you'll open up a potentially cavernous space.

(Note: I am not a coal miner, but I'm a fan of Homer Hickam's books Rocket Boys, Sky of Stone, and The Coalwood Way.)

[Porphyre]

Aug 1, 2014 4:42:54 GMT -6 Finarvyn said:

Totally off topic here, but this conversation makes me think about standard dungeon hallway dimensions. If you're slowly chipping your way underground, why make 10' wide hallways? I'd think that 3' to 5' would be a lot more realistic. I'm sitting in a bedroom typing on my computer, and the width of this room is around 10' or 11' and I'm trying to imagine someone digging something of this size ... just seems pretty huge, that's all.

Probably the Lovecraftian influences. Any antique construction must be at least cyclopean ! 

(the first french translations of the D&D modules made it even worst : they tried to round the numbers in the metric system , but they rounded up, giving us a 1 square = 4 meters ! )

[tog]

Aug 1, 2014 4:42:54 GMT -6 Finarvyn said:

I'm sitting in a bedroom typing on my computer, and the width of this room is around 10' or 11' and I'm trying to imagine someone digging something of this size ... just seems pretty huge, that's all.

Insane wizards and mad geniuses don't like feeling cramped.

[Deleted]

Fascinating topic and some great links to check out!

[tog]

Yep, you have to go to the Ready Ref Sheets for mining rates - they aren't covered in the OD&D rules, and not even in AD&D (much less the Dungeoneer's Survival Guide, f'ghu's sake!).

Now let's calculate how long it would take to excavate your typical megadungeon...

(EDIT: Homer Simpson voice: "Oh, Ready Ref Sheets... is there anything you can't do?")

[Merctime]

But... But... It's magic!!!

[derv]

Aug 1, 2014 4:42:54 GMT -6 Finarvyn said:

Totally off topic here, but this conversation makes me think about standard dungeon hallway dimensions. If you're slowly chipping your way underground, why make 10' wide hallways? I'd think that 3' to 5' would be a lot more realistic. I'm sitting in a bedroom typing on my computer, and the width of this room is around 10' or 11' and I'm trying to imagine someone digging something of this size ... just seems pretty huge, that's all.

I wonder what passage widths were like for pyramids or for coal mines.

Ways mentions Chainmails mining/countermining rules above. I figure this is what spawned Daves early dungeon delves.

Sapper's were Combat Engineers who directed the tunneling efforts during sieges. These tunnels were reinforced by wooden beams and posts much like modern coal mines The whole point of digging such tunnels was to undermine a castle wall or tower thus creating a breach. This was accomplished by mining a passage to the wall and further digging out an area large enough that the walls own weight would bring it down. Once this task was finnished, the tunnels were packed with combustables such as straw, tar, fat, and resinous material that would be lit on fire and burn down all the wooden supports causing the tunnels to collapse. The intense heat generated would also compromise the walls by causing them to crack.

All this to say that the size of the tunnels were proportional to the size, weight, and area of the walls or towers they were designed to collapse

Edit: I was just perusing a new book I recieved called Napoleonic Wargaming For Fun by Paddy Griffith. It has a section discussing Map Kriegspiel where it gives the following rates for a siege:

DIGGING POSSIBLE DURING AN AVERAGE DAY
In 24 hours each working party may:

Dig about 70m of sap
Build 1/3 of a battery
Build 1/2 of an infantry redoubt
Dig 5m of mine gallery
Arm battery, i.e., put in cannons
Arm a mine,i.e., put in a charge of powder

It then gives a diagram of a 36 day period for a successful breach to occur at these rates.

Granted this was during the gun powder period, the rates of digging and methods should not have changed much.

[tog]

Aug 1, 2014 4:42:54 GMT -6 Finarvyn said:

Totally off topic here, but this conversation makes me think about standard dungeon hallway dimensions. If you're slowly chipping your way underground, why make 10' wide hallways? I'd think that 3' to 5' would be a lot more realistic. I'm sitting in a bedroom typing on my computer, and the width of this room is around 10' or 11' and I'm trying to imagine someone digging something of this size ... just seems pretty huge, that's all.

I wonder what passage widths were like for pyramids or for coal mines.

Check out this post over at the Semper Initiativus Unum blog - all about a Roman limestone quarry repurposed into a MASSIVE NATO end-times bunker.

This massive complex was built from limestone, and was soft enough to cut with a chainsaw; the bunker was a "black hole" where everything that was brought in was thrown out in one of the underground landfill sites.

Admittedly the tunnels had to be large enough to drive through, but they're easily 20'+ wide, as the linked flickr set shows.

[tog]

BTW - some things I've come up with as a result of thinking about this subject:

WAND OF DIGGING: Each charge expended excavates a 5' X 5' hole 1d6x10' long through earth or stone. Will do 3d6 damage to Earth Elementals.

DIAMOND PICKAXE: Doubles mining rates.
PICKAXE ENCHANTMENT - "EFFICIENCY": Doubles rates of mining for each plus of efficiency (1-3).

ROCK MOLE: MV 30 ft. / turn; HD 3; AC 0; TT nil; AL N; AT 1; DAM 2-12; Burrows at full movement rate even through solid rock.

[Merctime]

Those items are too cool, tog I especially love the wand of digging!

ANIMATED EXCAVATION CART: This wondrous device is of old Dwarfish rune-craft, and bares many of the same over it's sturdy hardwood construction. These runes, requiring a spell to read languages (or magic; DM's call) for non-dwarves, give the instructions to utilize the device. There are three main functions to learn:'
1: One magic phrase activates the cart, and when spoken with a direction, animates the cart to move at a lumbering roll in that direction at a move of 3". This movement speed remains constant even if the cart is at maximum weight capacity (As a standard cart), or if it is traversing rough mine-floor terrain or at a slope of up to 45 degrees. Slopes greater than 45 degrees render it incapable of moving forward. Where turns are requiered, the phrase must again be spoken with the direction of the turn.
2: Another phrase causes the cart to dutifully come to a halt. Note that absence of this order may inadvertently cause the Animated Excavation Cart to go on until it may no longer do so; Hitting walls, falling into a chasm or lake, etc.
3: A 'boss', not unlike the round half-sphere used to reinforce a shield, adorns the front of this device. Usually cast of bronze, yet another phrase will cause it to illuminate as a continual light spell excepting that it provides a cone of light that extends up to 30' and is 20' wide at it's terminus. This may function indoors or out, and each speaking of the phrase produces light for 1 hour. Two hours must pass wherein no light is shed before this ability may be called forth again.