Talvivaara mine is like a big hole in the ground where people dig up things that we need to make batteries for phones and computers. The people who work in the mine wear special clothes and helmets to keep them safe.
To get the things out of the ground, the people use big machines that look like giant toys. They scoop up the dirt and rocks and take them to a big factory where the valuable materials are separated from the rest of the stuff.
But sometimes, things can go wrong in the mine and it can be very dangerous for the people who work there and for the environment around the mine. This happened at Talvivaara mine a few years ago, and some harmful things called chemicals got into the water and made it dirty.
The people who lived near the mine were worried that they might get sick from the dirty water, so the company that owned the mine had to work really hard to clean everything up. They had to stop digging at the mine for a while to make sure that everything was safe again.
Now, the mine is still there and people are still working to get the important materials out of the ground, but they are being very careful to make sure that nothing bad happens again.