Sterlite Industries (India) Limited - Sterlite Industries India Ltd.

Production Process
BALCO’s business has a number of elements which are summarized in the following diagram and explained in greater detail below:
* In response to recent global economic conditions and a decline in commodity prices, starting in February 2009, BALCO suspended part
of its operations at the 100,000 tpa aluminum smelter. Operations at this aluminum smelter ceased on June 5, 2009. At this aluminum
smelter, alumina from the refinery was dissolved in an electrolytic bath in a large carbon or graphite lined steel pot. An electric current
was passed through it to produce aluminum metal using VSS technology.
Bauxite Mines
BALCO has two captive bauxite mines, Mainpat and Bodai-Daldali, that provide all of its bauxite requirements for its alumina refinery. See
“— Additional Supply of Alumina.” As the bauxite deposits at these mines occur close to the surface, they are mined by open-pit methods. The
mining operation employed is semi-mechanized, where bauxite sorting and sizing are carried out through manual labor. Overburden, which is
in the form of soil and laterite, is first excavated by a combination of a shovel or excavator and a dumper in order to expose the bauxite ore.
The bauxite ore is then drilled and blasted. The blasted ore is sorted according to grade at the mine-face, and the rejected ore is back-filled into
the mine. The overburden is then returned and the area is leveled and reforested. The sorted ore is transported by road to the Korba complex for
further processing.
Alumina Refinery
BALCO’s alumina refinery at Korba uses the conventional high pressure Bayer process to produce alumina from bauxite. In the Bayer
process, caustic soda is used to extract the alumina content from ground bauxite, at temperatures suitable for the particular mineralogy of
bauxite, after which the resultant sodium aluminate solution is separated from the undissolved residue called red mud. The solution is then
subjected to seeded precipitation to produce alumina hydrate, which is then calcined into alumina and transported to the smelter.