360
T.G. Laperdina et al.
losses (Ministry Cabinet of the USSR 1988). During internal amalgamation in
barrels and mills, the correlation between mercury and extracted gold depends
on gold particle size and accounts for (4-lO):l.
Considerably smaller mercury losses take place in amalgamation of schlich
concentrates, although mercury expenses here are also significant. For example,
when gold was previously amalgamated in barrels, mercury expenses accounted
for lO-15 gIg of gold (Vyazelshchikov and Paritzky 1963). At present, mercury
expenses for amalgamation at the stage of finishing of gravity concentrates are
considerably smaller and can account for lOO-300 glkg of gold.
According to the data of the corporation Zabaikalzoloto, approximately 2 t of
mercury to 8 t of all processed gold arrived at gold-mining plants of the Chita
Oblast up to 1989 annually, which corresponded to its annual irreversible loss
and emission to the environment. It should be noted that in processing goldbearing raw materials, concentration methods of cyanidation and flotation are
widely used. Therefore the specific weight of mercury expenses per 1 kg of gold
was greater than by a simple division of mercury expenses by total gold
production, extracted by amalgamation, cyanidation and flotation (2 t per 8 tor
250 g of mercury per 1 kg of gold). It is impossible to make more accurate
calculations due to limited and sometimes contradictory information.
Incomplete burning of amalgams causes mercury content in concentrates sent
to refining plants to account for 0.2-4.0 glt (Ministry Cabinet of the USSR 1988).
As a result, mercury pollution of the environment and industrial spaces occurs
not only in the areas impacted by gold-mining activities, but also in the areas
near refining plants. According to the official data, in the USSR up to 1988 the
total irreversible losses of metallic mercury at dredges and washing devices
reached 6 tlyear, at gold dressing plants near 3 t/year (Ministry Cabinet of the
USSR 1988).
In the context of high mercury contamination of traditional gold-mining sites,
cases of mercury poisoning, increasing morbidity of the attendants, the Chief
Department on Precious Metals and Diamonds of the Cabinet of Ministers of the
USSR prohibited gold amalgamation at dredges and washing devices from
January 1, 1989, and from January 1, 1990 at gold extraction plants (GEP) and
gold dressing plants (GDP) (Ministry Cabinet of the USSR 1988). However, in
spite of the official prohibition, the use of amalgamation in gold mines still
persists to the present, especially at the stage of gravity concentrate finishing.
Thus, for example, there is evidence (Koledneva 1994) that when amalgamation
was used in one of the small mines of the Chita Oblast amalgam burning was
performed using the most primitive methods - on an open fire without mercury
vapour condensation due to the lack of necessary equipment. Since mercury
expenses from the process of gold amalgamation is not centrally accounted, it
is impossible to estimate accurately annual mercury emission to the environment in the mining and processing of gold-bearing raw materials. However, the increasing use of mercury by small mines appears to be inevitable at
present.
T.G. Laperdina et al.
losses (Ministry Cabinet of the USSR 1988). During internal amalgamation in
barrels and mills, the correlation between mercury and extracted gold depends
on gold particle size and accounts for (4-lO):l.
Considerably smaller mercury losses take place in amalgamation of schlich
concentrates, although mercury expenses here are also significant. For example,
when gold was previously amalgamated in barrels, mercury expenses accounted
for lO-15 gIg of gold (Vyazelshchikov and Paritzky 1963). At present, mercury
expenses for amalgamation at the stage of finishing of gravity concentrates are
considerably smaller and can account for lOO-300 glkg of gold.
According to the data of the corporation Zabaikalzoloto, approximately 2 t of
mercury to 8 t of all processed gold arrived at gold-mining plants of the Chita
Oblast up to 1989 annually, which corresponded to its annual irreversible loss
and emission to the environment. It should be noted that in processing goldbearing raw materials, concentration methods of cyanidation and flotation are
widely used. Therefore the specific weight of mercury expenses per 1 kg of gold
was greater than by a simple division of mercury expenses by total gold
production, extracted by amalgamation, cyanidation and flotation (2 t per 8 tor
250 g of mercury per 1 kg of gold). It is impossible to make more accurate
calculations due to limited and sometimes contradictory information.
Incomplete burning of amalgams causes mercury content in concentrates sent
to refining plants to account for 0.2-4.0 glt (Ministry Cabinet of the USSR 1988).
As a result, mercury pollution of the environment and industrial spaces occurs
not only in the areas impacted by gold-mining activities, but also in the areas
near refining plants. According to the official data, in the USSR up to 1988 the
total irreversible losses of metallic mercury at dredges and washing devices
reached 6 tlyear, at gold dressing plants near 3 t/year (Ministry Cabinet of the
USSR 1988).
In the context of high mercury contamination of traditional gold-mining sites,
cases of mercury poisoning, increasing morbidity of the attendants, the Chief
Department on Precious Metals and Diamonds of the Cabinet of Ministers of the
USSR prohibited gold amalgamation at dredges and washing devices from
January 1, 1989, and from January 1, 1990 at gold extraction plants (GEP) and
gold dressing plants (GDP) (Ministry Cabinet of the USSR 1988). However, in
spite of the official prohibition, the use of amalgamation in gold mines still
persists to the present, especially at the stage of gravity concentrate finishing.
Thus, for example, there is evidence (Koledneva 1994) that when amalgamation
was used in one of the small mines of the Chita Oblast amalgam burning was
performed using the most primitive methods - on an open fire without mercury
vapour condensation due to the lack of necessary equipment. Since mercury
expenses from the process of gold amalgamation is not centrally accounted, it
is impossible to estimate accurately annual mercury emission to the environment in the mining and processing of gold-bearing raw materials. However, the increasing use of mercury by small mines appears to be inevitable at
present.