Gravimetry is an underutilized geophysical survey method, even though it can be very effective when used appropriately and especially in parallel with other methods. A gravity survey provides diagnostic information about the density variations in the subsurface and helps identify the presence or deficiency of excess mass relative to the regional gradient. As explorationists learn more about deposit footprints this additional parameter of information becomes essential to development of a 3D geological model. At the local deposit scale, determination of excess mass in conjunction with a conductive and/or polarizable and/or magnetic source is vital in the evaluation of discovery opportunities.
Abitibi Geophysics offers both ground and borehole gravity surveys. Abitibi Geophysics is the only company authorized by Scintrex to offer Gravilog® in North America to the mining industry.
Applications in Mineral Exploration
|GROUND Gravity||BOREHOLE Gravity|
|Identifies anomalous excess mass: Massive sulphides, chromite ore, iron ore, stockworks, barite deposits, etc.||X||X|
|Identifies anomalous mass deficit: Coal, lignite, salt deposits, placer, karst, etc.||X||X|
|Differentiates conductor type with anomalous mass (e.g., graphite vs. sulphide).||X||X|
|Reveals the converse, where there may be a conductor but an absence of significant excess mass that could correspond to alteration, shear or fault zones.||X||X|
|Estimates tonnage of VMS conductors independent of their shape.||X||X|
|Determines bulk density of formations.||X|
|Introduces constraints to apply to 2D/3D inversions to a ground gravity survey.||X|
|Regional geological mapping: PGE exploration, sedimentary basin, batholith, diapir, karst, graben, etc.||X|