Borehole Surveys

Knowledge in the Field

"Borehole TDEM surveys are used to explore a considerable distance surrounding drill holes at a resolution that is not possible from surface.  Conductors that are not intersected by the drillhole and are too small to be imaged by surface techniques can be readily detected using a surface source and a downhole receiver.  Borehole TDEM surveys are useful if the holes are deeper than about 200 m; targets at shallower depths can be more economically detected with surface methods.  Mise-a-la-masse IP surveys use a source down the hole and an receiving array on surface surrounding the drill hole to quickly determine the primary direction of the mineralization .  Both of these techniques offer cost effective methods to vector towards mineralization in cases both where the hole intersected mineralization and near-misses.

Borehole surveys are used to locate deep targets near drill holes and to make detailed measurements of rock properties in-situ. Long used in coal and oil & gas exploration, they are increasingly applied in mineral exploration. Combinations of resistivity, natural gamma, temperature, density and neutron tools can be made to measure a wide variety of properties in one pass.  Applications include direct rock density measurements for tonnage calculations in oxide deposit development drilling, kimberlite facies identification, accurate mapping of alteration zones with natural gamma tools and the location of water inflow points with temperature logging tools.  

One big advantage of these shallow investigation tools is that they improve the quality of logging possible in RC holes and thus provide an alternative to expensive diamond drilling in some situations. 

AGL Delivers

AGL offers Protem BH43-3D borehole surveys, mise-a-la-masse IP surveys and hallow investigation physical property surveys including:

• Resistivity
• Natural Gamma (T-U-Th-K)
• Spectral Gamma
• Temperature
• Induction
• IP