Diamond bedrock core drilling uses a diamond-impregnated coring bit to collect undisturbed rock core samples from bedrock.  The drill stem typically consists of an inner core barrel and outer drill steel which allows for the retrieval of individual rock core intervals without the removal of the entire drill stem from the corehole.  Drilling fluids (water, mud, etc.) are circulated down the inside of the drill steel and out of the end of the drill bit to help reduce friction at the drill bit and remove drill cuttings from the corehole. Rock core can be collected in a variety of diameters depending upon the goal(s) of the exploration program and the capabilities of the individual drill rigs. 

Diamond rock core drilling is typically employed in geotechnical exploration applications when samples of the bedrock need to be evaluated for engineering properties.  Diamond rock core drilling can be very time consuming and expensive, and is usually reserved for projects which aim to utilize the bedrock as a source of construction materials (i.e. quarry, mine, etc.) or for projects which will bear directly on, or into, the bedrock body itself.