* some areas like the city of Essen have dropped by 16m, others up to 40m due to mining. Running the pumps to prevent flooding is considered part of the Ewigkeitskosten (eternal costs, see: https://de.wikipedia.org/wiki/Ewigkeitskosten ).
edit: fixed numbers, added link
What did they do with the flame retardants? Spray parts of the mine with them?
Blaenau Ffestiniog
Ahh. It's always raining up top. Makes perfect sense. :)
Looks like they thought this through far more than you give them credit.
The article makes no mention of the troubles and dangers the original parent suggested.
Either everyone in the article, professors, mine owners, etc. are idiots and the grandparent is the one voice of reason in the world, or maybe, just maybe, they've already thought of this.
I was trying to be polite, but the airmchair naysaying on HN is wearing at times.
I occasionally feel the same frustration you do with the naysaying here, but I'm even more frustrated by the hand-waving that accompanies some of the innovations presented here. The naysayers were right about Theranos and Juicero, there's a possibility that they could be right about this idea (or on any other topic) as well.
The article mentions only upsides and opportunities. Not a single downside is mentioned, no risks are addressed. Either there are no downsides, or the article is one-sided, in which case we should appreciate the additional context and information provided by the "naysayers" here.
First, despite all the kickstarters for urban, vertical, undeground or underwater lettuce farms... Lettuce farms are fine where they are. If you want LED grown lettuce, they can grow that there too. Grow outside the city and drive produce to the city in a car. If you want to go green, use an electric car.
There's no need for the farm to be underground... on earth, at this point in time.
This besides the (insightful) about how hard it is to make mines safe to access, barley safe, assuming a very active safety system.
..and ok sure, I concede exceptions. In that case, I think (1) the tradition is of hiding from the law has produced quirky horticultural practices (piping in air and exhaust for plants is normal) (2) they don't really care about unit costs and (3) they're growing a plant that costs $10k per kg! They need security like a jewelry shop.
A mine is not some kind of free underground cave, it's an industrial installation requiring constant engineering. They have 24/7 command centers that monitor and correct safety parameters before anyone is allowed to go in. When mines close, they are flooded, refilled or sealed, to prevent underground explosions and collapse that could kill people above. The closure of mines is itself a dangerous and expensive operation.
Bottom line, if it ain't worth going down there and picking unlimited quantities of coal worth $70/ton, it most certainly isn't worth it to invest and labour for months in a high risk environment, only to get limited quantities of agricultural produce worth $200-$300/ton.