The first stage in diamond exploration is the identification of an area or region having the potential to host diamond deposits. Sometimes this process is simplified by a previous diamond discovery, for example, the Slave craton in Canada's Northwest Territories and Nunavut. In other circumstances, where diamond bearing discoveries or economic deposits have yet to be realized, a variety of geological disciplines including geophysical, mineralogical, morphological and structural studies are used to direct the focus of exploration efforts.
After a region deemed to be prospective has been selected, specific target areas must be defined. This is commonly accomplished through indicator mineral sampling, an exploration technique used throughout the world by companies searching for diamonds. Results from regional scale sampling programs can be used to identify areas for mineral claim acquisition.
Geologists refer to areas that return notable concentrations of indicator minerals as "anomalous". These areas are then further investigated by using more detailed indicator mineral sampling grids as well as geophysical techniques. Geophysical surveys allow explorers to infer the geological formations and structures that lie beneath the surficial overburden and lakes. Airborne geophysical surveys are generally used to cover large areas very rapidly. Ground-based geophysical surveys are used to refine any targets identified from airborne surveys and to further investigate potential targets identified through indicator mineral sampling, prospecting or geological mapping.
After collection, indicator mineral samples are pre-screened to remove gravel, cobbles and other large non-kimberlitic materials and then shipped to the laboratory for further processing. Stornoway's laboratory uses a flexible combination of methods to process glacial till and fluvial samples to determine the abundance and nature of the kimberlitic indicator minerals that they contain.
Initial processing begins with primary concentration through the use of a Wifley table. This device takes advantages of the higher specific gravity that characterizes indicator minerals and allows them to be separated from the other sample material through the use of a thin film of flowing water coupled with agitation. In addition, indicator mineral processing techniques utilize a variety of other methods.