process mineralogy

Minerals are the essential components of mineral deposits. In a practical sense we can think of two principal categories, ore minerals (potentially valuable) and gangue minerals (waste), although this simplistic division occaionally leads to ambiguity in the clasification of a particular mineral. The numbers and proportions of minerals vary throughout a mineral deposit, in some cases more or less systematicallly, in other cases seemingly erratically.

Similarly, mineral textures can be very different from one part of a deposit to another. Variations in mineralogy, mineral abundances and textures can impact severly on the economis viability of a deposit, thus emphasizing the need for a through understanding of the mineralogic characteristics of an ore deposit at the earliest possible stage of evaluation. As indicated in the quotation by Kingston, above, a continuing refinement of the mineralogic characteristics of a deposit is essential in order to stay alert to potential for improving mineral recovery.

There are many ways  to study the mineralogy  of a deposit beginning with the very classical megascopic techniques applied to the first explaratory drill core and, perhaps, supplemented by binocular microscope examination. From this simple beginning, the method s of mineralogic investigation become increasingly sophisticated and in many cases require highly specialized types of instrumentation that are not widely available.

One tried and true approach to the examination of minerals is through the use if optical microscopy, the ‘transmiting’ microscopein the case of transparent minerals (most gangue minerals are transparent) and the ‘reflecting’ microscope in the case of opaque minerals (most ore minerals are opaque). Technique involving the reflecting light microscope (see examples in Figures 1 and 2 below) are referres to as ‘minealography’ and when dealing specifically with practical aspects of the ore minerals are commonly referred to as ‘ore microscopy’.

 

written by natalia(dita)