Maceral analysis categorizes the microscopic constituents of coal according to morphology and reflectance.  It can then used to determine the proportion of reactive to inert macerals for prediction of various coal quality parameters.  In our laboratories, maceral nomenclature follows the definitions of the International Committee for Coal & Organic Petrology, which are recognized by ASTM, ISO, and the Australian Standards Institute. However, the distinction between the Vitrinite submacerals, Telovitrinite and Detrovitrinite, has been shown to be unreliable, and although required in Australian analyses, the subdivision is not made in North American laboratories, nor incidentally, in the ICCP’s own Accreditation exercise.

Petrographic Reports

Our petrographic reports are intended for presentation. We know that they are sent by client coal companies to steel producers from India to Mexico, and from Brazil to Korea and beyond, where they are well received. The reports include information on the provenance of a sample and the methods of sample preparation, and analytical techniques used on the sample.

For each coal sample received for full analysis, a summary of relevant petrographic parameters is presented as well as graphical content. Typically these reports are sent in Microsoft Excel format, but can be created in many formats available in today’s wired world. All reports are time-stamped to indicate when the analysis was completed and by which analyst. Reports can be easily customized for many different databases or formats for easier integration with existing systems, be that an acQuire database system, or other geological data management system.

Automated Group-Maceral Partitioning

In addition to the carefully measured manual maceral count, we are able to provide automated group-maceral partitioning from Fingerprint data. A probability plot overlay of our Fingerprint (the Reflectance Profile), provides a very quick visual appraisal of the Vitrinite and Inertinite contents of a coal. The location of the inflection point of the curve separates these two group-maceral populations, and the percentages of each can be read from the ordinate on the right of the graph, uniquely validating a manual maceral count.

Petrography is used by coal-producers to evaluate the nature of coal deposits, to confirm the quality of vessel or train cargoes, and to show the uniqueness of a specific product relative to another.  Steel producers use petrography as an aid in the design of coking coal blends, to help in trouble-shooting problem-cokes, and to confirm the nature of vessel or train cargoes. Steam coals can benefit from an evaluation of the Liptinite content, because Resins and Liptinites have elevated volatile contents, and strongly impact on a coal’s reactivity, and ignition stability.