Our Data is often get compared to the accuracy of a laser scan for volume calculations. On a conical pile, it’s true, we are very comparable!
However, the story changes a bit when you get an oblong pile with various angles and abutments. These create small indents and caves which cannot be see line of sight from the ground.
Meaning your options with a laser scanner are either: climb the pile, which is Dangerous, Or, make assumptions which are Inaccurate.
We suggest option 3; Get a Drone survey and leave that headache in the past.