Because most designs and topographic maps are prepared using computer-aided drafting techniques, we use several software packages to rapidly extract and evaluate the data. Details of the process are as follows.

• base maps provided or developed in AutoCad.
• files imported to MapInfo using in-house code.
• vertices added using another in-house routine.
• x, y, and z extracted using VerticalMapper.
• data gridded using VerticalMapper.
• new grid files of the differences between the surfaces generated using VerticalMapper.
• difference grids contoured & the volume represented by the area of the contour region determined using an in-house developed code.

Examples of the kinds of volumes that can be calculated are:

• final cover to base of excavation (total site capacity);
• current topography to base of excavation (volume consumed to-date)
• current topography to last year's topography (volume consumed during the period); and
• final cover to current topography (volume remaining).

If the limits are carefully chosen, sub-areas of these grids can be used to estimate the volume of soil remaining to be excavated or the volume available in existing stockpiles.