Edition · 02 · October · 2006
The GMP Campaign Launch
Salam Emas
The aim of the GMP is to share
In his speech, Duwel Rawing said
the knowledge and experience of
that he welcomes the initiative and
the UNIDO technical team with
supports the objectives of the
In this second issue of our newsletter we focus on
miners and the urban community,
project. He also commented on the
burning mercury more safely. This is because the
including the owners of gold
danger to health from mercury
public health issue of mercury vapor in the air is a
shops. The project focus is not
exposure, and the environmental
serious issue which must be addressed with
only on the health and
impact. The community should be
practical information and advice.
environmental impacts of gold
able to improve their livelihoods by
processing but also on improving
adopting the more efficient gold
At the start of September, our team was given further
the incomes of miners through
processing equipment and
training to build their capacity to broadcast this
optimizing simple technologies.
technologies.
message to the mining community and to
demonstrate safer technology, such as retorts.
Directly after the training, our mercury-reduction
campaign was officially launched. This public event
was well attended by the local community,
broadcast live by local radio, and reported on by
the major provincial newspaper, the Kalteng Post.
Following this event, our trainers from the
Departments of Health, Education, Environment
and Mining held a public-awareness campaign
over the six weeks leading up to Idul Fitri. We have
held public lectures, screened films and distributed
brochures to hundreds of residents in Kereng Pangi
to raise awareness on mercury issues.
Furthermore, we have visited the students of the
elementary, junior high and senior high schools of
the town to educate the younger generation on this,
The Global Mercury Project Team in Central Kalimantan
and other health issues.
At the launching, the Bupati of
We are now ready to meet and train miners
Katingan District, Duwel Rawing,
returning to the field once again. We are pleased
assisted by the Head of Mining
that the people of Kereng Pangi are willing to listen
and Energy Department , Marzaki
and to learn about the dangers of mercury. We are
Djimat, introduced important
also very grateful for the support and assistance of
equipment for gold processing
the district government in our efforts to raise the
that can help reduce the use of
awareness of the public.
mercury and the impact on
miners and the environment, and
Wishing you a safe and prosperous new year,
improve livelihoods.
The UNIDO team demonstrated
an improved sluice box with
Sumali Agrawal
different types of carpet to capture
Editor
more gold. They also showed how
to reduce and recycle mercury,
and the use of a retort and
fumehood to capture mercury.
Fumehood demonstration
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Edition · 02 · October· 2006

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Retorts: Solutions from
around the world
A retort is a container in which the gold-mercury amalgam is
placed and heated; volatile mercury travels up through a tube
and condenses in an adjacent cooler chamber. With retorts,
mercury recovery is usually higher than 95%. Substantial
reduction in air pollution is obtained. There are a large variety of
retorts. Some of them are made with stainless steel while others
use inexpensive cast iron.
Home-made retorts can also be made of steel tins, an
inexpensive option for retorting that has been applied in Papua
New Guinea and China. The Chinese two-bucket retort consists
of a metallic bucket and a bowl filled with water. A larger bucket
Solution for miner in Laos
covers the first bucket containing the amalgam.
The idea of using kitchen bowls covered with a bucket
was also used by UNIDO to fabricate a retort in El Callao,
Venezuela. This was a more elaborate retort built on a
steel table but using a stainless steel bowl as a
crucible. The table was filled with water and the
amalgam burned with a blowtorch from the bottom. As
the crucible was thin, the retorting time was short (10
minutes). Mercury condensed on the wall of the cover
and dripped into the water. This retort took 10 to 15
minutes to eliminate most of the mercury from the
amalgam using a propane blowtorch. A serious
inconvenience of this, and other retorts, is that
sometimes miners remove the cover (bucket) from the
crucible while the retort is hot. When this occurs, miners
are exposed to mercury vapor.
Marcello Veiga
A home-made retort from China(left) dan Papua New Guinea (right)
Chief Technical Advisor - The Global Mercury Project
The PNG "fish-tin" retort employs the same concept, but uses
fish tins and wet sand instead of water. In both cases, mercury
vapors condense on the cover-bucket walls.
Using the same principle of the fish-tin retort, UNIDO built a retort
using kitchen materials for the ASM in the Mekong River in Lao
PDR. On a metallic support, a small enameled steel tray with
amalgam is placed inside another larger steel bowl, covered
with a glass bowl and sealed with sand. The glass bowl allows
the miners to see the amalgam decompose, but it can be replaced
with a metallic bowl. Mercury condenses on the bowl walls and
drops into the sand. This retort cost less than US$ 10 to build.
Miners can recover the condensed mercury by panning the sand
placed around the small tray. To avoid discoloration of gold,
miners use a glazed-steel (enameled) bowl as a crucible.
Solution for miners in Venezuela
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Edition · 02· October · 2006

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Using Retorts Safely
Always seal the retort tightly so that no gas escapes
during the burning process.
Use stainless steel or enamel bowls as crucibles to
Kitchen bowls can be sealed by placing upside-
avoid discoloration of gold
down in a bed of wet sand or water.
Tins such as fuel-tins can be placed in a deep tray of
Burning in a retort will remove 95% of the mercury
water. Small holes made around the edge of the tin will
from the gold. Further burning and melting of the gold
allow the gas to dissolve into the water more easily,
will remove this residual mercury, but it should be done
but these holes should be at least 15cm below the
inside a ventilated fume-hood or a chimney with a
water-level.
blower, to avoid breathing the 5% that remains.
Pipe Retorts
Pipe retorts are very strong,
and can be heated until gold
melts inside the crucible.
Although this takes a long time
to achieve, the gold will
therefore be of high purity.
Gold like this contains residual mercury and should be burned again inside a fumehood
Kitchen Bowl Retorts
bowl as a cover, as it will cool
down in only 5 minutes.
These are efficient retorts that
The use of simple kitchen-
have the advantage of cooling
bowl retorts can reduce the
more quickly than pipe retorts. If
mercury in air to safe limits,
a glass bowl is used as a cover,
as proved by UNIDO in
the burning process can be
Mozambique. If a gas torch is
observed.
used, the burning process can
However, glass takes longer to
be done very quickly, and
cool down than metal, so it is far
these retorts can also be
Above: closed tightly, the retort is ready to use
better to use a stainless steel
cooled very quickly.
Below: the simple components are easy to open
Advice from the Clinic
A warm retort may still contain
more quickly. Mercury
inner surfaces from
mercury as a gas. Do not open
evaporates at room
escaping. It is also best to
a retort unless it is quite cool.
temperature so retorts should
store the retort in a closed
Use a wet towel and a bucket
always be closed to prevent
container or under a wet towel
of clean water to cool a retort
the mercury that is stuck to the
when not in use.
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Edition · 02 · October · 2006

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Two Steps for Purifying Gold Safely
Why use a retort?
Using a fumehood
The principle of a retort is that
A fumehood is a ventilated
Mercury also causes tremors,
fumes away from the operator
amalgam is heated inside a
chimney that sucks conta-
loss of vision and hearing,
and into a water tank that
closed system. This allows the
minated air away from the
paralysis, insomnia and
captures the vapor.
mercury to evaporate (it
operator.
emotional instability.
becomes a gas) and then to
It must be remembered that
condense (it becomes a liquid
A good retort will remove 95%
It is therefore important to use
mercury vapors are dangerous
again) so that it is separated
of the mercury from gold
a fumehood during the final
to all people, and should
from the gold and so that it can
amalgam and this mercury
stages, so that the residual
always be contained as much
be used again.
can be used again. However,
mercury will not poison the
as possible. With the
5% of the mercury may remain
operator.
technology of retorts, most of
in the amalgam and this
the mercury can be removed
residual mercury also needs
Blowers and fans should
safely, and the gold can then
to be processed safely.
always be used when gold is
also be purified safely using a
being purified. The fumehood
fumehood that blows the
below uses a blower to suck
contaminated air into a filter.
Step One: Use retort
to burn the gold safely
New retorts
Step Two:Use a fumehood
to purify the gold further
To prepare a new retort for
use, burn all the metal
To purify the gold further,
surfaces inside and outside
operators must burn the gold
first and allow it to cool. Before
again and also melt the gold.
using gold amalgam, slowly
Good ventilation is very
burn a little mercury inside the
important at this stage as
retort. This mercury is likely to
mercury gas is always
stick to the surfaces inside the
dangerous.
retort and may not come out.
The retort can now be used for
High doses of mercury can be
gold, but it is advisable to dust
fatal to humans, but even low
the crucible with baby powder
doses can have serious
at first, to prevent any gold from
impacts on the central nervous
sticking to the surfaces.
system, kidneys and liver.
Prototype fumehood, designed and built by the technical school in Palangka
Penerbit:
Yayasan Tambuhak Sinta
Rumah Emas Kita
Staf Redaksi
Jl. Teuku Umar No. 32 A
adalah buletin yang terbit
Palangka Raya 73112
dua bulan sekali untuk
Bardolf Paul
Kalimantan Tengah - Indonesia
memberikan informasi
Sumali Agrawal
Telp. +62 (536) 32 37184
kegiatan Global Mercury
Dzul Fikri Al Huda
Fax. +62 (536) 32 29187
Project di Galangan-
Mayang Meilantina
Email: tambuhaksinta@gmail.com
Kalimantan Tengah
Kartie Vitamerry
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Edition · 02· October · 2006

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