The definition of the path of boreholes and other in-hole measurements needed to control the direction or obtain rock related data is the realm of Pajari Instruments Ltd. expertise and the purpose of its products and services.

Pajari Instruments Ltd. has been doing all these things worldwide for over 65 years.

Briefly, holes bored into the earth for exploration, mining, engineering, scientific, fluid extractive or fluid transportive purposes need to be defined/located in 3 dimensional earth space. The beginning (collar) of the hole can be located (surveyed) by traditional surveys or GPS without problems.

Beyond the collar lies the path of the earthbound borehole that is never naturally straight without some type of human intervention or control, and that path is not available for direct observation.

So, a valid question about a borehole is "Where did it go?" Or if the drilling had produced samples of a particular rock traversed in the borehole, the question might be "Where exactly was this sample rock located in the earth?" Yes, the path of the borehole can deviate sufficiently to make answers to these questions critically important.

If surveying the borehole as it progresses tells you the hole isn't going to hit the 'target' you set, you can proceed to change its direction by using wedging or directional drilling techniques. To set up the in-hole tools that will effect the change in direction toward your target requires tool-facing surveys.

The rock samples (called core) obtained by core-drilling contain features such as bedding or fracture planes. Once the core breaks away from the rock it was a part of, the rotational orientation is lost. If the attitude of these planes in the undisturbed rock is important, then a facing survey must be made of the core before it is broken free.