Reclaiming Colliery waste heaps

The difference between the photo on the left, and that on the right is 17 years: Colliery waste tips (all the shale, sandstone, etc. dug from 300-800 metres below that wasn't coal) created huge mounds of dead ground several hundred feet high and covering hundreds of acres. After 300 million years of post carboniferous era interment it wasn't exactly rich soil. Once the pit tips were surplus to requirements they were/are landscaped and coated with topsoil. In 1983 the saplings in the top picture were as high as is shown. In 1999 they had got as big as the trees in the next picture. Rother valley leisure park is a reclaimed opencast mine.

Reclaimed pit tip 1983Same reclaimed pit tip 1999

Below is the wasteland left over from the pit closures of the early 1990s (this one from the old Thurcroft pit in 2001), which obviously has a lot of room for recovery, and judging from the evidence above, it's going to take at least 20 years. The wooded scenes above looked a bit like the scene below back in the 1970s.
Thurcroft pit tip 1999