e-mail :

Registered in England and Wales company # 03449181.
 This website does not use cookies.

 © Copyright: Conwy Valley Systems Limited  2000-2017.

Conwy Valley Systems Limited,

Wells House, 12, Hawes Drive,

Deganwy, Conwy, LL31 9BW, United Kingdom.

VAT# GB 741 5190 48


A Geoscience Wales  founding member.

PETROG Home PETROG Home PETROG search

Click here to download our PETROG Coal brochure

PETROG and Coal


Microscopical methods for quantitative determination of phase percentages based on point counting, although time consuming, are the most reliable techniques available.


PETROG reduces the time required for analysis, increases the reliability of data collection and provides an audit trail by combining repeatability (re-mounting a slide and returning to any previously logged position) with cross-reference of images to visual analysis.


Point counting is performed at the mine, for QC and grading purposes, and prior to use, for instance in steel manufacture for accurately controlling the feed rate and relative proportions of coal and other constituent materials.

PETROG is the world’s foremost point counting tool, across all types of analyses and for all materials, and is used for coal quality analysis in all of the major coal-producing areas, including Australia, South Africa and North America, and in the main steel-producing plants in India and elsewhere.


PETROG supports both reflected light microscopy and transmitted light

microscopy, and can be used to accurately locate points previously analysed, or later to be analysed, by other methods, such as scanning

electron microscopy.


PETROG primarily supports manual analysis, with images used to allow logging directly from a monitor and/or for subsequent quality assurance or re-analysis, but the availability of images for every point also allows image analysis and PETROG uses patented methods for analysing composition based on a training set provided by the user.

Point counting standards that are supported by PETROG include:


ISO 7404 and in particular parts 1 to 5 referring to methods for petrographic analysis, determining maceral group composition, microlithotype, carbominerite and minerite composition and determining microscopically the reflectance of vitrinite.


ASTM D2799 Standard Method for Microscopical Determination of Volume Percent of Physical Components of Coal and D7708 Standard test method for microscopical determination of the reflectance of vitrinite dispersed in sedimentary rocks.


Australian Standard 2856 which is based on ICCP & ISO with additional contributions by coal petrographers in Australia, including particularly incident light microscopy for Maceral analysis and microscopical determination of reflectance of coal macerals.

The large number of points required by most international standards requires a systematic and automated tool.


The Prior/Swift point counter was originally designed for this purpose but ceased production in 2002, by which time PETROG was already established as the next generation of point counting tool, bringing the method fully into the digital age with database support, and the SteppingStage removed the manual mechanical element of the process, fully automating the movement in both x and y directions.


The SteppingStage has been significantly improved since 2002 and the software has continued to innovate, maintaining the position of PETROG as the automatic choice for petrographers in all industries, throughout the world.


PETROG is recognised by the ICCP and APG (Applied Petrography Group of the British Geological Society) as meeting and exceeding all relevant standards and protocols.