Confusing mercury chemistry with the essentially glassy behavior of uranium is a problem for you I think. As the USGS points out "The vast majority of coal and the majority of fly ash are not significantly enriched in radioactive elements, or in associated radioactivity, compared to common soils or rocks."
http://pubs.usgs.gov/fs/1997/f... So, your claim of extra radioactivity as a result of coal burning would have to be the same as a claim of extra radioactivity from using a bulldozer on a construction site. Just moving stuff around with the same uranium content does not change the background level of radiation,
,
You've misread the table you cited. Notice that in the first column Fe is already greater than 10% yet it is a minor constituent in table 2.