fac09,
The picture below should answer your original question.
However, I am not sure I did understand your geometry correctly, please check.
I assumed you are interrested in the volume of an hemisphere having a cone removed from it, as in the picture below.
I guessed from your drawings that you would like to take into account the additional effect of this volume being packed down, not touching completely the dome. If this is right, you should simply take that into account by applying an additional factor on the result (see below last formula).

In the lower right, I give the formula for the volume of deep-yellow part of the dome.
This formula is rather easy to prove:
The volume of an hemisphere is:
Vo = 2/3 Pi R³
The surface of an hemisphere is:
So = 2 Pi R²
The surface of the dome cap that is empty of material is:
S1 = 2 Pi R² (1-sin(q))
Therefore the volume removed from the dome is:
V1 = S1 / So Vo = 2/3 Pi R³ (1-sin(q))
Therefore the volume of the dome filled with material is
Vdome = Vo - V1 = 2/3 Pi R³ sin(q)
To take an additonal "packing down effect" would give the volume of material:
Vmaterial = Vdome * h(actual) / h(maximum)
The formula for the dome cap can be found in many formularies or can easily be calculated by integration.
Michel