There are more than 12,000 abandoned coal mines across China, offering vast amounts of underground space and sophisticated infrastructure that could potentially be repurposed and researchers have an idea about how to do just that.
The idea, from a team at the Shanxi Province Coal-based Resources Green and High-efficiency Development Engineering Center, is to use the tunnel and cavern networks for “agricultural experiments”, turning these spaces into farming labs.
Let’s get the obvious downsides out of the way first: There’s clearly no sunlight or rainfall underground, which is usually crucial for farming.
However, as the researchers outline in a paper published in China Mining Magazine, there are upsides too.
Subterranean environments can be carefully controlled, and are protected against fluctuations in the weather, ongoing climate change, and natural disasters.
“Against the backdrop of intensifying global climate change and growing agricultural demand in extreme and enclosed environments, exploring experimental agricultural models in coal mine underground spaces carries important scientific significance and engineering value,” write the researchers in their published paper.
“The results show that coal mine underground spaces possess the engineering foundation for constructing agricultural experimental units when the surrounding rock stability meets engineering specifications, and ventilation, drainage, and safety monitoring systems are complete,” write the researchers.
“Through artificial light sources and environmental control systems, underground spaces can realize the independent supply and precise regulation of key production factors such as light, heat, water, air, and carbon, thereby supporting the implementation of highly controllable agricultural experiments.”
Another bonus of farming underground is access to geothermal energy. The researchers suggest this could be tapped into as a sustainable heat source for crops, with far fewer greenhouse gas emissions.
What’s more, contaminated groundwater that leaks back into the mines and becomes contaminated, through sulfates, metals, and other particles, could be treated underground and reused for irrigation.
True but they would probably build such farms in subways or other regular buildings instead of former mines of questionable structural stability.
Given how many old mines China has, I’m sure lots of them are perfectly structurally stable, and can be further reinforced if needed. The appeal here is that the hard work of digging them out has already been done providing a huge amount of unused space, and since they’re deep in the ground, you get free insulation, potential geothermal energy for power, and water from underground sources. Another factor that’s unique to China is their massive high speed rail system that connects the whole country. This significantly changes the logistics story compared to anywhere else in the world.
I’m sure building vertical farms in cities would work as well, but that might actually be a bigger effort than simply refurbishing the mines. And it’s possible China will pursue both approaches as well. There tends to be a broad spectrum approach to try lots of different things all at once and then see what works I find.
Agreed.