Hovis builds a garden office*

At 1g/cm^3, thats around 7 tonnes. Probably around 120 wheelbarrow loads?

Also bear in mind that loose soil is also 2-3 times the volume it was in the ground, so you'll be looking at 14-20 cubic meters of loose soil to go somewhere else or dispose of.

Get a mattock if you don't have one, it'll make breaking up the ground much easier.

A good shovel is better than a flat garden shovel for moving the loose earth.

(Recently dug a trench for a new garden wall and a slab for a bin store.)