The elements or component parts of coal. These are determined by chemical
analyses that may be performed in different ways. An ultimate analysis
provides exact information as to the percentages of the various elements
(such as carbon, oxygen, and hydrogen) present in the coal. Another method
is by proximate analysis, which determines the relative percentages of
carbon, moisture, volatile matter (such as gas and tar), sulfur, and ash.
Dictionary of Mining, Mineral, and Related Terms