Tracer Gas as an Aid in Mine Ventilation Analysis

The Bureau of Mines has s u c c e s s f u l l y used s u l f u r h e x a f l u o r i d e (SF,) a s a t r a c e r gas t o measure mine a i r f lows under c o n d i t i o n s where c o n v e n t i o n a l methods have f a i l e d . SF, was employed e x p e r i m e n t a l l y t o measure a c c u r a t e l y r e c i r c u l a t i o n o f r e t u r n i n t o i n t a k e a i r caused by leakage through a n o l d s t o p e d a r e a , t o check f o r p o t e n t i a l leakage from a n a d j a c e n t mine , t o t r a c e 10,000 c h of " l o s t 1 ' a i r from a n i n t a k e a i r w a y , and t o measure t r a n s i t a i r time through uranium mines . It proved u s e f u l a s a means o f a c c u r a t e l y measuri n g a i r f l o w volumes i n a i rways of l a r g e c r o s s s e c t i o n and v e r y low f low v e l o c i t y , and i n de te rmin ing t h e r e c i r c u l a t i o n r e s u l t i n g from underground c o o l i n g p l a n t s .