It seems that mining has become a topic of interest in the Olympia Mailing list as of late. For all of you newbies and experienced players a like, the Crimson Dragons are proud to allow you access to this article on mining. Thanks to the mystery writer.
Although any of iron, gold and mithril can be mined at any depth, the
yields vary with depth as suggested in the rules, with roughly these
numbers:
Depth Iron Gold Mithril
1 15 25 0
2 12 100 0
3 10 200 0
4 8 400 0
5 5 500 0
6 3 400 0
7 ? 150 0
8 ? 25 1
9 ? ? 1+
The numbers for iron and gold are fixed at each depth (mostly as above,
though I've not checked the numbers and they may be slightly wrong). The
mithril yield varies apparently at random, with 1-2 common at the 6-10
depths but yields as high as 8 appearing as depth increases.
If you only want mithril, it still makes sense to mine iron and gold at
first, just to deepen the mine in a reasonable length of time. Each
mining action takes 6 days once experience is high enough, but each type
of mining can only be done once per turn in each mine. It may be useful
to have more than one mine, with workers kept in garrisons at each site
and a single mining noble who flies between them each turn. In ideal
conditions this can produce an income of 1500 gold per turn, much better
than a castle.
Mines suffer damage, randomly but related to depth - a deep mine will
suffer several separate damages each turn. It feels as if there's more
damage when the mine is being worked, but I've no stats to back that up.
If a noble is in the mine when it takes damage, they lose some workers.
I've never heard of a noble being wounded or killed mining, but it could
be that the damage is applied like combat - first to the followers and
only if they're all killed, passing through to the noble directly.
As mines get deeper, the number of workers required to maintain them increases.
The problem with a small number of workers is that they take more days to
repair the continuous damage, and so more damage occurs while they're in
the mine and more are killed. At some point they start to be killed faster
than the mining noble can replace them in the shrinking part of the turn
that isn't taken up by the ever-slower repairs. My approach these days is
to collect an extravagent number of workers (100+, or whatever the garrison
will stand) before digging down to the dangerous depths (beyond about 5),
so repairs only take 1 day most turns. Even so, there comes a time when
the damage rate is too high and it's better to let the mine collapse (while
no-one's inside - that might be bad for one) and start another somewhere
else.
The most unpredictable part of the mining profit, but the reason for much
of it, is the chance of finding a gate crystal. These are extremely rare
(some people have found one, sometimes with a _lot_ of mining, others have
found none) and can be found while mining any of iron, gold or mithril. It's
unclear whether depth makes a difference, they certainly _can_ be found in
shallow mines.