Autodesk CIVIL3D - CIVILDESIGNCOMP 2007 SLM CD Tutorials Manual page 612

The cut volume above the balance line is entirely free haul. Notice that
now there is a red, overhaul volume below the balance line. You will
balance the fill volume in the following procedure.
Balance fill material volumes
1 Below the balance line, zoom in to station 6+25 on the mass haul line.
Notice that this is near the point at which the overhaul volume (in red)
and the free haul volume (in green) meet the mass haul line. If you
examine this station on the profile, you see that it is also a relatively flat
section of the existing ground surface. Flat areas can also be good locations
for dump sites and borrow pits.
2 At station 6+25, hover the cursor over the mass haul line.
Notice that the tooltip displays the current station number and volume,
which is approximately 2000.00 Cu. Yd.
3 Select the mass haul line. Right-click. Click Mass Haul Line Properties.
4 In the Mass Haul Line Properties dialog box, click the Balancing Options
tab.
5 In the Add/Remove Borrow Pits And Dump Sites area, click Add Borrow
Pit.
600 | Chapter 16 Material Calculation Tutorials