Hacker News Reader

Comment by speedplane | Hacker News Reader

Mines are "perfect" farms? I remember hearing once that in order to grow, plants need this thing called light.

LEDs for fibre options to bounce sun light in.

The tunnels wouldn't get big changes in temperature, would only get the water it needs and you could have light running 24/7.

But you have to pay that power bill for the other 12 hours the sun isn't shining.

Plus, drilling to install fiber-optic cables will be a huge expense. And, in order to collect enough sunlight to light the mine the area above the mine will still need to be blanketed with collectors. After all, you can't collect enough sunlight to feed 1m^2 of plants from a 1cm^2 area at the surface. Efficiency losses will actually require >1m^2 area at the surface to capture adequate light, so why not just avoid all the additional expense and put a greenhouse on the land above the mine?

> But you have to pay that power bill for the other 12 hours the sun isn't shining.

This is really a bizarre objection. What do you think overground farms do at night?

The grandparent specifically said "lights running 24/7"

>so why not just avoid all the additional expense and put a greenhouse on the land above the mine?

If only the article covered the advantages this approach has to offer over surface green houses..... oh, wait!

It's not even that I'm convinced their approach is viable, but how about at least critiquing their answers to your questions?

mushrooms don't. Then again, growing mushrooms in the dark isn't much of an innovation, they've been doing it in France since the 17th century.

Mushrooms aren’t plants.

But they are food..

Try reading the article. For shafts close to the surface they can use fibre optics to bring in sunlight, deeper down they use LED lights.

Sunlight is ~1,000 W/m^2. Even accounting for the efficiency boost of only using photosyntheticaly useful parts of the spectrum, the quoted energy cost feels off by one or two decimal places.

There is also the point that sunlight is free, and greenhouses already solve the same problems. The Netherlands already does this to great effect: https://www.nationalgeographic.com/magazine/2017/09/holland-...

Tunnels have much better and cheaper climate control, easier access to water, cheaper land costs. It's not necessarily a case of one one single variable determining the viability of the whole idea especially when this is, as I said, _covered_ _in_ _the_ _article_.

No idea if this will ever come to fruition, but these people do seem to have done some homework and have prototypes up and running now.

Any ideas what the ratio of drift mines to deep mines is in the UK?

I think most of our disused mines (by area) are deep, and pretty dark places - don't even need to reach pit bottom for total blackness.

Having been down a mine few times not sure I'd want to farm down there!

Surely the real answer is to grow the same foods in commercial greenhouses, heated via geothermal heat pumps and if we're short of land to do this we can always use golf courses for farming!

>if we're short of land to do this we can always use golf courses for farming!

I really would not like to have to test the UK's government on security of food supply vs love of golf courses. I suspect I already know the answer to that one and it comes in a variety of pastel tones.

:-)

Remember reading somewhere that in the UK we use roughly the same amount to land for golf courses as we do for housing.

Of course not all golf courses are suitable for farming but I'm sure there's plenty in Surrey that are!

That's pretty dodgy. It only includes land with actual bricks and mortar on it, not including land with residential use such as drives, paths and patios let alone gardens. Even then the land used by golf courses was probably overestimated by about 2x.

https://www.ft.com/content/79772697-54e4-32c9-96d7-5c1110270...

Reply on news.ycombinator.com