Dimensional analysis would suggest that the critical angle for dirt piles would be independent of the amount of dirt (for amounts of dirt larger than, say, 10^{5} dirt particles). Assume the height of an average molehill is 15cm, and that you wish to build a 1.5km high mountain on the beach (i.e. starting from a flat base at sea level). Then you're looking at something 10^{4} times larger, but with the same shape. Therefore you'd need approximately 10^{12} molehills to make this mountain.

#### IMPORTANT NOTES:

- Most mountains exist in mountainous regions, therefore the assumption they stick up 1.5km higher than their surroundings is patently ridiculous. But even assuming we just wanted to go 150m above a plain, we'd need about 10
^{9} molehills, which is still fairly large (see below).
- The cost of earthworks is usually calculated by the volume of dirt you wish to move. However, in this case you're also lifting the dirt a long way up, which would increase the price (need to construct a road, pay more for fuel, and make longer journeys with each load).
- Also, most construction cost calculations would ignore the cost of
*finding* 10^{9} molehills in the first place; you'd also need to send out teams to dig them up and load them on your truck.
- Mountains don't really look like molehills; they tend to have cliffs and huge rocks, which you cannot get in an accretion of molehills (some of the rocks will be far larger than even a complete molehill!). Therefore it's probably impossible; however, the same calculations may be performed for hills, which are probably more like molehills.