ABSTRACT
Laboratory investigations are normally requested when the suitability of a rock or soil for a particular use must be assessed and their composition evaluated. Soil and rock used for engineering construction is always classified by laboratory tests and this requires the general composition of these materials to be assessed. Their composition is only evaluated in detail when the presence of unstable minerals is suspected. Care must be taken when sampling soil and rock to ensure that the sample is representative of the particular material to be investigated, and that its disturbance during sampling will not adversely affect the results of the tests to be performed upon it. In practice, two categories of sample may be obtained: routine sample and research sample. The difficulties of obtaining routine samples using conventional methods of commercial sampling are illustrated by Kallstenius and Rowe.
