Bank density is the density of a material before it has been disturbed by excavating attempts. This is a physical property that varies from material to material. It is the density 'in-situ' or in-place.

Loose density is the density of a material once it has been disturbed or otherwise displaced by mining or excavation operations. The disturbance aerates the material and generally increases the distance between particles, making it less dense than original conditions. The inherit increase in volume of a constant mass of material is referred to as swell.

Materials generally have Bank Density > Loose Density. For example, dry clay has a Loose Density of 68 lb/ft³, but a Bank Density of 85 lb/ft³. Similarly, Limestone has a Loose Density of 99 lb/ft³ and a Bank Density of 163 lb/ft³.