The Richmond Mine at Iron Mountain, Shasta County, California, USA provides an excellent opportunity to study the chemical and biological controls on acid mine drainage ~AMD! generation in situ, and to identify key factors controlling solution chemistry. Here we integrate four years of field-based geochemical data with 16S rRNA gene clone libraries and rRNA probe-based studies of microbial popu...

We evaluated the depth-dependent geochemistry and microbiology of sediments that have developed via the microbially-mediated oxidation of Fe(II) dissolved in acid mine drainage (AMD), giving rise to a 8-10 cm deep "iron mound" that is composed primarily of Fe(III) (hydr)oxide phases. Chemical analyses of iron mound sediments indicated a zone of maximal Fe(III) reducing bacterial activity at a d...

P r e v i o u s s t u d i e s of t h e o x i d a t i o n of i r o n p y r i t e and t h e subsequent r e l e a s e of a c i d i t y i n t o mine d r a i n a g e w a t e r s have provided no c o n c l u s i v e r e su l t s i n a s c e r t a i n i n g which of t h e s t e p s i n t h e o v e r a l l r e a c t i o n i s r a t e d e t e r m i n i n g . Although microorganisms have f r e q u e n t ...