Estimating rockfill unit weight based on its gradation characteristics

[georam]

This may be a simple solution.
Assume no moisture - rockfill materials. When rockfill is placed in a truck for weighing (assume loose), the unit weight would be unique, based on (a) gradation, (b) particle shapes, and (c) Specific gravity of rocks. For (a), the well graded the rockfill, the voids will be less.. and therefore it will have higher unit weight. For (b) the rounded particles may prevent for more packing of materials and unit weight may be lower.
Is there a simple estimate to calculate this? It may be a function of voids. The voids in the volume depends on how well graded the gradation and the particle shapes.
Unit weight = W/V. The Spec. gravity will account for this, as the heavy the rock (granite vs limestone), the unit weight will be higher. Thanks for info

 

[miningman]

Two tonnes per cubic metre. Any refinement on this estimate requires an awefull lot of work in terms of blasting enginnering / rock fragmentation, in situ measurements of SG.... which might vary across thev project etc etc. Definitely a case of diminishing returns on increasing effort.