Microbial Ecology Assessment of Mixed Copper Oxide/Sulfide Dump Leach Operation

Conference · Tue Jun 01 00:00:00 EDT 1999

DOI:https://doi.org/10.1016/S1572-4409(99)80082-0· OSTI ID:911303

Bruhn, Debby Fox; Thompson, David Neal; Noah, Karl Scott

Microbial consortia composed of complex mixtures of autotrophic and heterotrophic bacteria are responsible for the dissolution of metals from sulfide minerals. Thus, an efficient copper bioleaching operation depends on the microbial ecology of the system. A microbial ecology study of a mixed oxide/sulfide copper leaching operation was conducted using an "overlay" plating technique to differentiate and identify various bacterial consortium members of the genera Thiobacillus, “Leptospirillum”, “Ferromicrobium”, and Acidiphilium. Two temperatures (30°C and 45°C) were used to select for mesophilic and moderately thermophilic bacteria. Cell numbers varied from 0-106 cells/g dry ore, depending on the sample location and depth. After acid curing for oxide leaching, no viable bacteria were recovered, although inoculation of cells from raffinate re-established a microbial population after three months. Due to low the pH of the operation, very few non-iron-oxidizing acidophilic heterotrophs were recovered. Moderate thermophiles were isolated from the ore samples. Pregnant liquor solutions (PLS) and raffinate both contained a diversity of bacteria. In addition, an intermittently applied waste stream that contained high levels of arsenic and fluoride was tested for toxicity. Twenty vol% waste stream in PLS killed 100% of the cells in 48 hours, indicating substantial toxicity and/or growth inhibition. The data indicate that bacteria populations can recover after acid curing, and that application of the waste stream to the dump should be avoided. Monitoring the microbial ecology of the leaching operation provided significant information that improved copper recovery.

• Research Organization: Idaho National Lab. (INL), Idaho Falls, ID (United States)
• Sponsoring Organization: USDOE
• DOE Contract Number: DE-AC07-99ID-13727
• OSTI ID: 911303
• Report Number(s): INEEL/CON-98-00539; TRN: US200724%%672
• Resource Relation: Journal Volume: 9; Conference: Biohydrometallurgy and Environment Toward the Mining of the 21st Century,El Escorial, Madrid, Spain,06/20/1999,06/23/1999
• Country of Publication: United States
• Language: English

Related Subjects

99 - GENERAL AND MISCELLANEOUS//MATHEMATICS, COMPUTING, AND INFORMATION SCIENCE
ARSENIC
BACTERIA
COPPER
CURING
DISSOLUTION
ECOLOGY
FLUORIDES
GROWTH
INHIBITION
INOCULATION
LEACHING
MINING
MIXTURES
MONITORING
OXIDES
PLATING
SULFIDE MINERALS
TOXICITY
WASTES
autotrophic bacteria
copper oxide
heterotrophic bacteria
leach
micobial
sulfide dump