LOW RADIOACTIVITY PORTABLE COAL FACE ASH ANALYZER

A coal face ash analyser based on gamma-gamma technique has been devel oped and tested at two coal mines. It is light in weight (2 kg) and us es two very low activity sources which ensure safe operation of this h and-held radiation instrument. The primary source of radiation is a 1. 8 MBq Ba-133 gamma-ray source. Another 0.35 MBq Cs-137 gamma-ray sourc e is used for gain stabilization. At field tests at a Queensland coal mine, ash in the range 7-23% ash was determined with a root mean squar e deviation of 2.6%. At a New South Wales coal mine, ash in the range 4-31% was determined to 3.3%. (C) 1997 Elsevier Science Ltd.