Inoculum
Mixed cultures of mesophilic, moderate, or thermophilic
microorganisms are used to effect biooxidation in a GEOLEACH™ heap.
Inoculum in the required quantity is grown up on site,
starting with a small volume of culture from the laboratory.
The microbes are grown in a solution of nutrient salts,
with periodic addition of small quantities of sulfide
concentrate or ore and elemental sulfur. The suspension
is agitated and aerated. As the microbial density increases,
the inoculum is transferred to progressively larger vessels
and diluted by the addition of nutrient medium. This process
is repeated until the required volume of inoculum is obtained.
The GEOLEACH™ heap is inoculated by adding the bacteria to the ILS pond or added directly to the heap after the pH conditions for microbial growth have been established.