• English

Subject: Draft Revised UNFC-2008 and Draft Accompanying Explanatory Note From: Ken Mallon, Petroleum Geology Consultant

January 5, 2009

Ken Mallon comments regarding the Draft Revised UNFC 2008
Overall, an outstanding document – extremely readable, and a vast improvement over previous versions in simplicity.

  1. Figure 1: I like the figure, but I still think the 3D cube needs some vertical dashed, etc., lines connecting the categories and classes to assist the observer in lining-up the cubes so that he or she can readily visualize the cube relationship that forms a class, such as 111, or 223, etc.

  2. Section III, item 5: this is a terrific explanation of the revised and unique numerical definition of a class.

  3. There is a disconnect between the footnotes for Figure 2 in the actual draft and those in the draft that is included within the Explanatory Note. This has led to confusion regarding the footnote numbers and the actual footnotes (the problem is that the Explanatory Note has 2 footnotes on page 1 that are not in the actual UNFC draft). This could easily be resolved by including only the basic Explanatory Note as an appendix, or attachment to the actual UNFC document.

  4. G4 needs to be expanded to account for a range of uncertainty, like other classes.

The following comment refers to the Explanatory Note and its relationship to the Draft Revised UNFC 2008:


(1a) Item 4 in the Introduction explains the purpose of the Explanatory Note, but states that it is not part of the classification itself. In my opinion, the Explanatory Note is so informative that it really should be an appendix or attachment to the classification (see my comment #4, above). Perfect examples of its importance are the sequences from Items 21 through 24, explaining why the “reserves” term is not used in the classification, and Items 26 and 27, explaining the communication of “uncertainty” in the revised classification. I think these items, especially those pertaining to “reserves”, are excellent and critical to the revised UNFC.

(1b) My only concern here is that any translation of these Explanatory Note Items is efficient, so that their true meaning is presented in all languages.
I hope my comments serve some useful purpose.


Ken Mallon,
Petroleum Geology Consultant
Personal associate (at-a-distance) member of AHGE