When the total heavy mineral concentrate is larger than can be examined conveniently on a microscope slide, large sampling errors may he introduced during the selection of a portion for examination. Results are given of a series of tests, designed to ascertain both the most practical method of sampling very small amounts and the relative importance of various causes of sampling difficulties. New techniques for obtaining minute samples are described. The methods and conclusions may be applied to any mixtures of sand grade-sizes such as concentrates of microfossils.

First Page Preview

First page PDF preview
You do not currently have access to this article.