I have a quarry that I want to make a bit shallower, it is around 3 acres and around 100ft deep, any ideas on how to fill the bottom up a bit.
Current idea is to push in the sides, making surface area larger and bringing the bottom up a bit, but that will be difficult as it was a dolomite quarry and wed be trying to dig into rock.

Any other ideas or advice, preferably something that will be a bit cheaper than the above.

Thanks in advance