The strategy of drilling was to drill the hole perpendicular to the strike of the lava and conglomerate beds, so that the location of favorable layers (those with copper) could be found. There were many miles of core obtained, and only a small fraction are kept in order--some are spilled out near mine buildings such as the Osceola #3, where their labeling is lost! A shame since it is very expensive to do again. There is a Michigan Core Repository at WMU, and one for UP materials at KI Sawyer.
To find the ore before sinking a shaft was vital for the success of the mine. One tool was drilling a hole from the surface to collect cores and see where there was ore. The area around Calumet was drilled a lot and this helped to guide shaft locations. Drilling is expensive and required experienced drillers. The core was logged and stored in a drill shed in labelled boxes for use by geologists in planning shafts.
