Borehole Surveys

Knowledge in the Field

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. Borehole EM and IP/Resistivity surveys are used to explore a considerable distance surrounding drill holes.  Both of these techniques use sources at surface (EM) or down hole (IP) and large arrays at surface surrounding the drill hole.  In general, borehole EM or IP surveys are useful if the holes are deeper than about 200 m; targets at shallower depths can be more economically detected with surface methods.

AGL Delivers

AGL offers borehole mise-a-la-masse IP surveys and shallow investigation physical property surveys including:

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