Okay kiddo, so imagine you have a toy box that's gotten really full and messy over time. You know there's some cool toys in there, but they're buried under lots of old broken toys and junk.
Well, sometimes grown-ups have a similar problem with garbage. Instead of a toy box, they have a big area where they dump all the trash from their houses and businesses. This is called a landfill.
Landfills are not very helpful to the environment because they take up a lot of space and the trash buried there can release harmful chemicals into the ground and air. But here's where the idea of landfill mining comes in.
Just like how you go through your toy box to find the good toys, grown-ups can go through the old garbage in landfills to find anything that could still be useful or valuable. They can use machines and tools to dig up the trash and sort through it, looking for things like metal, plastics, and even old food that can be turned into compost.
It's a lot of work and not always worth the effort, but some people think it's a good way to reduce waste and find things we might have thrown away too soon. Plus, it's a way to "clean up" some of the old garbage from landfills so it doesn't keep causing problems for the environment.