Re: (TFT) Forge of Fury. --> Ricks comments.

[Mark Tapley <mtapley@swri.edu>]

John Hyland observed:

> Goat herding and mushrooms only get you so far.

Quite true; I should have clarified that that would only be a 
supplementary food source. (And possibly other useful products. Wool? 
Leather?) Nice in that both cheese and mushrooms can command premium 
prices per volume, but the day-to-day fare is going to have to be 
bartered for, I believe.

rsmith replied:

> 	I am uneasy about having the chimney
> coming out under the glacier.  A huge amount
> of glacial till (crushed rock and soil) is
> under the glacier.  This icy mud and boulders
> would plug up any chimney in short order.
> Also, the glacier would rip open any small
> holes in short order.  (The moving ice, if
> it can get a grip, can move huge rocks.  The
> red rock in Australia was moved by a glacier
> for example.)  Rocks would get wedged into
> the hole, and as they are dragged away, they
> would pull away the sides of the chimney.
> Now bigger rocks can be forced in etc.

Yeah, where *is* the other half of Half Dome, anyway?

Good points, and ones I'd thought about only superficially.
My founding assumption was that glaciers move on a slow time-scale - 
say a few meters, or even tens of meters, per year. Slow enough that 
the chimney exhaust would melt ice away from the catch-basin rapidly 
enough that there was no problem with damage to the catch-basin or 
surrounding rock.

I had completely ignored the till problem. I think that would have to 
be solved by dwarves with fresh-air items (and an air lock or two) 
carrying the stuff out of the catch basin area as it gets melted free 
of the glacier.

> 	If you heat the bottom of a glacier,
it melts a bit and starts flowing quicker.

Uh-Oh. That could be a problem. I'd assumed the heat only affected 
the ice quite locally, so that the rigidity and drag of the ice all 
around is what supported the above-rock part of the chimney. As the 
glacier moved, the chimney would form a crevasse, eventually closing 
up some distance downstream. But if the heat spreads laterally, the 
whole glacier could surge forward. That could be bad.

Stan Suggested:

So you have water flowing in one direction and a constant air current in the
> other direction.

Neat! Could do it without warm air, just by using pressure gradient 
(as in rsmith's post), if winds against either side of the range are 
consistent.
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