in my experience, coal is the most difficult mineral to analyse because of the large variety of coal qualities and also because of the different measurement bases used
i found this website today (link below) when i was running the ruler over the GMM announcement
i punched the variables, with formulas, into a spreadsheet, so i can compare coal companies and announcements
below is the website link, the website technical info & my spreadsheet
i will try to add another companies into the spreadsheet, to help its accuracy
i hope what i am doing is correct and any feedback is most welcome
for example, when i spoke to GMM today, they said my conversion was not 100% correct
for example, when using the comparative values in the table, i converted 7,200 kcal/kg daf into 5407 kcal/kg ad but GMM said the old Soviet results had 5890 kcal/kg ad
