Published online by Cambridge University Press: 01 May 2009
Portable apparatus for obtaining small oriented cores for geophysical or geological purposes is described. It consists of a 34 c.c. two-stroke engine with a 12 ft. long flexible shaft to a drilling head which accommodates the drilling bit and includes a pipe through which coolant from a pressure container may pass. All this weighs under 50 lb. Imperfectly cylindrical specimens may be obtained by hand drilling, or perfect cores with the aid of either of the two rigs described. The first weighs 21 lb. and allows a number of closely spaced specimens from horizontal and inclined outcrops to be obtained. The second weighs 15 lb. and is for obtaining specimens some fixed distance apart from more difficult vertical faces. Magnetic and non-magnetic orienting devices are described. The merits of the method of sampling are briefly discussed.