Vertical boreholes, such as historic gas wells in advance of mining developments, are often unable to be accessed from the surface. In these cases, horizontal drilling can be employed to verify the locations. REI can develop parallel horizontal boreholes on either side of a magnetic anomaly, and use a magnetic gradiometer to verify the vertical hole location with a high level of accuracy. This novel approach allows mines to locate objects such as vertical well casings, giving the confidence to continue development.
