All exploration companies usually do it as a first step. It also...

All exploration companies usually do it as a first step.
It also gives the Geologists the chance to identify what rock types are around,
And areas to further focus on for Magnetic Surveys, Drilling Etc.

They have a good understanding of what Minerals are near what types of rock,
And how old the formations are,
Which helps them further Identify areas of further interest,
As well as where is most likely to host which Minerals / the Target mineral, etc.

They can then do Magnetic Surveys etc. to identify Areas to Drill
And / or start Drilling with a better idea,
Of where is the most likely to host what they aiming for.
Than just randomly drilling a given Tenement.

It saves time and money to focus on the areas,'
Most likely to host the Intended target of the Drilling Campaign....