Stockpile Volumes and Tonnages by Remote Means

Key results:

• This research has demonstrated that gravity surveying methods can achieve the resolution necessary to determine the tonnage of coal in a stockpile.
• Tonnages can be determined without using on pile measurements if microgravity techniques are employed.
• Low stockpiles are not amenable to this technique and may be better treated using density meters or other established methods.
• Stockpiles closely associated with other active stockpiles or excavations need to be surveyed collectively.
• Satisfactory results are achievable using commercially available gravimetric and survey instrumentation. Data processing for this project used algorithms and software freely available within the geophysical industry of Australia albeit in an innovative manner.

Achievements compared with objectives:

• The research demonstrated a means of directly determining the mass of a stockpile
• The integration of airborne photogrammetry and gravity surveying was demonstrated as a means of determining volumes and tonnages of a stockpile with the emphasis on zero or minimal physical presence on the surface of the stockpile.

Potential of Technique
The future of the technique is seen in the measurement of large piles of variable density that are not amenable to the extrapolation of bulk density measurements made on their surface.

The same methodologies can be applied:

• to reconciliation of excavated material from voids such as open pits,
• the measurement of compacted backfills and the variations in the compaction densities of those backfills,

The methodology would lend itself to the development of a continuous monitoring system using buried sensors under the stockpile.