This is the most recent soil mining area, a spot that I'm turning into a parking space for the pickup truck. It's hard to tell from the photo, but the giant hole (which was 9'x16' and 2' to 3' deep) is almost filled in. Just a small spot by the white bucket still needs some rocks. Just a few more buckets of rocks and the area is ready for a topping of gravel.
This is just one example of what I can do to put a spot back into use after mining the soil. Oh by the way....the answer is "yes". Yes, I have that many rocks on my farm that I can use as fill. I save the big and pretty rocks for stone walls, with the rest being used like this -- fill.
Other past mined pits were used to make growing beds. Some holes were filled in as a hugelpit....woody material on the bottom, organic debris atop that, and a cap of compost, soil, and mulch. These pits make super growing beds. I currently have bananas, turmeric, sweet potatoes, and pipinolas growing in such beds.
Another pit I've been using for organic debris that I don't deem fit for veggie growing areas. I'll layer in dog poo and kitty box tootsie rolls with grass clippings and a bit of soil. This is also how I deal with donkey and sheep manure the day after they are dewormed, so that most of the residual dewormer goes into the pit. Once the pit is mostly filled, I'll plant a tree there. (I think I've mentioned this before, but at my age, it's news to me!) It's a good way to mine soil from a smallish pit and turn it into a tree growing spot.
To tell you the truth, I never thought I'd be mining soil until I moved to this place. Wherever I lived before, soil was a given. It was everywhere. Nothing like living on the side of an active volcano to make one appreciate real soil that you could sink a shovel into.