Help with DMG mining cubic volume, p.106

[Agglomérante]

I'm having trouble interpreting Gygax's cubic volume table on p. 106 of the DMG. Here are the first two rows, with the three columns on the right representing the type of rock being mined.

MINING: CUBIC VOLUME OF ROCKER PER 8 HOURS LABOR PER MINER

[table="width: 500, align: left"]
[tr]
[td]Race of Miner working[/td]
[td]very soft[/td]
[td]soft[/td]
[td]hard[/td]
[/tr]
[tr]
[td]gnoll, halfling, human[/td]
[td]75'[/td]
[td]50'[/td]
[td]25'[/td]
[/tr]
[/table]

Do I take the cubic root of the value to determine the volume of rock or are those values (e.g., 25') the length, width and depth of the cube of rock being mined?

 

[trancejeremy]

What I thought he meant was the number of 10' squares on graph paper. So if it was very soft, it would be 7.5 10x10 squares on graph paper, soft 5, hard 2.5.

 

[howandwhy99]

The answer is up to you of course. What does hard, soft, very soft, (or your densities) mean for rock?
What about all the other materials?

As a wild guess I think Gygax meant "cubic feet", as in 75 cubic feet for very soft rock. This makes the ratio 13
On the other hand it might mean a single cubic space with a single length listed. This makes the ratio: 1:8:27 (cubic expansion)

I'm guessing the first, but you might want to refer to a geology textbook.

 

[Man in the Funny Hat]

Not sure what's confusing about it. The indicated race (with a pick and shovel I assume) can, in 8 hours, mine a cubic volume of X. So if it's 75' cubic volume you take the cube root of that which is a bit over 4.2'. So in 8 hours you can chip away a cube of rock about 4.2' on each side. Now that does SEEM awfully low to me especially for "soft stone" like sandstone, though IANAM (I am not a miner). But then it also states rather clearly it's not meant to be realistic but to just give a DM numbers to work with.

 

[Agglomérante]

Not sure what's confusing about it. The indicated race (with a pick and shovel I assume) can, in 8 hours, mine a cubic volume of X. So if it's 75' cubic volume you take the cube root of that which is a bit over 4.2'. So in 8 hours you can chip away a cube of rock about 4.2' on each side. Now that does SEEM awfully low to me especially for "soft stone" like sandstone, though IANAM (I am not a miner). But then it also states rather clearly it's not meant to be realistic but to just give a DM numbers to work with.

You're right, I should just plop the numbers into a formula and be done with it! I'm lucky to have a figure to work with at all, even it is seems too small an amount.

 

[Agglomérante]

Not sure what's confusing about it.

Alright, I've dropped the numbers into a formula for my scenario of three, 8-hours shifts of 10 skeletal Dwaves digging continuously into hard rock for 500 years.

Using the cube root of the 35' provided by Gygax for each Dwarf per shift, a passage that's 10' high by 10' wide will be 33.72 miles long after 500 years.

Gotta love the AD&D DMG.

 

[Man in the Funny Hat]

Alright, I've dropped the numbers into a formula for my scenario of three, 8-hours shifts of 10 skeletal Dwaves digging continuously into hard rock for 500 years.

Using the cube root of the 35' provided by Gygax for each Dwarf per shift, a passage that's 10' high by 10' wide will be 33.72 miles long after 500 years.

Gotta love the AD&D DMG.

Yep. It's a requirement.