Transcript Overview of Best Practices and Field Experience in

Overview of Best Practices
and Field Experience in
Artisanal and Small Scale
Gold Mining in Nigeria
BY
OPAFUNSO, ZACHEUS OLANIYAN
(MSc (Rapid City, USA), MBA (Vermillion, USA), PhD (Akure, Nigeria),
FNSE, MNIM)
PROFESSOR OF MINING ENGINEERING & AG. DEAN, SCHOOL OF
MANAGEMENT TECHNOLOGY (SMAT),
THE FEDERAL UNIVERSITY OF TECHNOLOGY, AKURE (FUTA),
NIGERIA
EMAIL: [email protected]; [email protected]
Abstract
This paper presents an over-view of field experience in
artisanal and Small Scale gold mining operations in
Nigeria and recommends best practices for such
activities to take care of the associated dangers and
environmental effects. Current technical data on ASM
gold mining operations such as manual breakage,
washing and winning, panning, and mercury
amalgamation methods were examined with a view to
recommending international best practices for the
industry.
Abstract Contd.
Environmental effects of the use of mercury to recover
gold from gangue were also discussed. The paper
conclude that artisanal gold mining in Nigeria is ripe for
a revolution that can lead to the birth of a modern and
environmentally friendly method of mining for the
benefits of ASM operators, the Governments and the
communities where gold mining operations take place.
Key words: Gold, Mercury, amalgamation, pollution,
mining, operations, communition.
INTRODUCTION
 Definition of Artisanal and small-scale mining:
-
as mining activities that uses crude or
rudimentary methods to extract and
process minerals and metals on a small scale
-
it encompasses all small, medium, informal,
legal
and
illegal
miners
who
use
rudimentary
processes to extract minerals
from secondary and primary ores.
Introduction cont’d
 Artisanal miners work in:
*
*
difficult and often very hazardous conditions
in the absence of the required safe mining
knowledge or any regulations
* or standards, toxic materials can be released
into the environment, posing large health
risks to the miners, their
families and
surrounding communities
 Thus, gold mining operations are particularly
dangerous, as they often use the mercury amalgamation
process to extract gold from ores.
Introduction cont’d
 Despite serious dangers occasion by this activity,
artisanal gold mining operations continue to spread
due to:
*
rise in the demand for gold
*
unattractive nature of other means of
livelihoods such as farming in the areas where
the mineral is substantially available.
 The environmental effects of artisanal gold mining
activities, has spurred a number of environmental
conscious organizations including United Nations to
seek for alternative ways of recovering gold
Factors influencing participants in the vocation
 Lack of Organization and Instabilities of the
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miners
Illiteracy
Lack of technical assistance
Lack of Financial assistance made available to the
artisans
Improper regulations guiding the operations of the
miners
poverty and unemployment;
Gold Occurrence and Mineralization
in Nigeria
 Gold in Nigeria is found in alluvial/eluvial placers and
primary veins from several parts of supracrustal (schist)
belts in the Northwest and Southwest of Nigeria.
 The most important occurrences are found in the Maru,
Anka, Malele, Malendo, Sofon Birnin Gwari-Kwaga,
Gurrara, Bin Yauri, Okolom- Dogondaji, Ijero - Ekiti and
Iperindo areas, all associated with the schist belts of
Northwest and Southwest Nigeria.
 There are also a number of smaller occurrences beyond
these major areas. (NGSA, 2010)
Location of Gold Occurrences in
Nigeria (source: MMSD, 2010)
Table I: Locations of Gold Deposit in Nigeria
Location
State
Geopolitical
Zone
Maru
Zamfara State
North West Zone
Anka
Zamfara State
North West Zone
Malele
Zamfara State
North West Zone
Sofon Birnin
Kaduna State
North West Zone
Malendo
Kebbi State
North West Zone
Bin Yauri
Kebbi State
North West Zone
Gurrara
Niger State
North Central
Gwari
Zone
Okolom -
Kogi State
Dogondaji
Ipinrindo -
North Central
Zone
Osun State
South West Zone
Ekiti State
South West Zone
Ilesa
Ijero - Ekiti
Major Areas of Gold Mineralization in Nigeria
(Source: NGSA, 2010)
Statistics of Gold production in
Nigeria (NGSA, 2010)
Field Experience in Small Scale Gold
Mining in Nigeria
Gold Production is by
Manual Method
 The
production of Gold in
Nigeria has not been through
mechanization
methods
of
mining as a result of the nature
of the deposit as highlighted
above.
 Methods
used for mining
operations include:
*
crude methods of manual
breakage
to
have
access to the deposit.
*
washing
and
winning
through panning, and
*
finally
amalgamation
mercury
Typical Manual Washing
Method
Method of Recovering of Gold in Nigeria
Stages in Mining of Gold
 Breakage
 Communition
 Gravity
Concentration
Process
 Sluicing and
Disposal
 Amalgamation and
Burning Process
Typical Amalgamation &
Burning Process
ASM Methods of Gold Mining
Manual Breaking
Communition
 The ASM operator uses
 During this stage, the
manual method of
breaking the rocks
containing the Gold
deposits to get lumps.
 This is then transfer
into the communition
section.
operator engages his
wife/wives and
children to further
break the lumps into
smaller pieces using
metallic mortar and
pestle.
ASM Methods of Gold Mining Cont’d
Gravity Concentration
Process
Gravity Concentration
Process
 This is done by mixing
 The upper sediment is
the pulverized ore with
water and then
allowing it to settle
after agitation.
 Regular agitation takes
place every day for
about a week.
transferred to another
tank and the same
process is repeated.
 The lower sediment
which is rich in Gold
goes through the next
stage of sluicing.
ASM Methods of Gold Mining Cont’d
Sluicing and Disposal
Sluicing and Disposal
 This is commonly done
 There is always a sieve
with a wooden sluice
box.
 The ASM operator tilts
the box in a small angle
to allow the sand
particle move in an
upstream and a
downstream manner.
at the intake section to
prevent large particles
from passing through
the sluice box.
 Visible gold is picked
out of the sluice box,
amalgamated for the
recovery of pure gold.
Amalgamation and Burning Process
 Artisanal gold miners combine mercury with gold-
carrying silt to form a hardened amalgam that has picked
up most of the gold metal from the silt
 The amalgam is later heated with blow torches or over
an open flame to evaporate the mercury, leaving small
gold pieces.
 The gaseous mercury is inhaled by the miners and often
by their immediate family, including their children.
 Mercury that is not inhaled during the burning process
often settles into the surrounding environment or
circulates globally for future deposition far from the site
Amalgamation &Burning Process Cont’d
 The deposited mercury is absorbed by a variety of
living organisms
 This transforms elemental mercury into methyl
mercury
 Methyl mercury is one of the most dangerous
neurotoxins that contaminate the food chain through
bioaccumulation
 Ores recovered from alluvial deposits are also
subjected to gravity concentration and the other
processes follow suits.
Environmental Effects of Artisanal Gold
Mining activities
 Gold mining activities have mainly been done through
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crude methods of mining with consequential hazards to the
health of the miners, their respective families and the
communities surrounding such mining activities.
some environmental hazards of mining activities are:
Mercury pollution:
Water pollutions
Landscape degradation
Destruction of habitats
Loss of organic soil
Deforestation
Best Practices in ASM Gold Mining in
Nigeria
 As a result of catastrophic event in Zamfara State
last year which led to the death of over 400 children
due to lead poisoning, the United Nations has
recommended proper enlightment and training for
the artisanal miners of Gold in the affected areas in
Nigeria.
 This will enable them to know and adopt best
internationally recognized practices for safe mining
operations in their community.
Best Practices in ASM Gold Mining in
Nigeria Cont’d
 Best practices in artisanal gold mining will be the
method that will reduce the environmental pollution,
health hazards occasion by the use of mercury in the
recovery of Gold especially with the method of
amalgamation. For the purpose of this presentation,
we shall look at the best practices from three
perspectives:
 Exploration Methods
 Exploitation Methods
 Processing Methods
Best Practices in ASM Gold Mining in
Nigeria Cont’d
 Veiga (1997) suggested four different approaches to
solve mercury problems, namely:
 Armed or Enforcement Approach:
 Legal Approach:
 Ecological Approach:
 Educational Approach:
Best Practices in ASM Gold Mining in
Nigeria Cont’d
 technically, Veiga, (1997) suggested the following
three solutions that can lead to mercury reduction:
 Search for alternative processes to avoid mercury
 Implement remedial procedures to highly polluted
sites
 Apply measures to reduce mercury emissions’
Best Practices in ASM Gold Mining in
Nigeria Cont’d
 Telmer (2007) outlined four strategies that can lead to
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reduction of mercury use in Artisanal small scale gold
mining to be:
Introducing improved mining practices, including the
elimination of whole ore amalgamation and open-air
amalgam burning;
Introducing Hg free processing where viable;
An increased price for mercury;
Awareness campaigns, policy and governance reforms,
and community economic diversification
Strategic Plans to Introducing
Mercury Free Method
In other to have a mercury free method in artisanal
gold mining in Nigeria, the following strategic plans
that had worked in Brazil and Venezuela can be
implemented in Nigeria:
 The International Guidelines on Mercury Management
must be put in place; the effort put in by the organizer
of today’s Anglophone West Africa Regional
Awareness-Raising Workshop on Mercury in Artisanal
Small Scale Gold Mining is commendable.
 National Law on Mercury Management must also be
formulated and implemented
Strategic Plans to Introducing
Mercury Free Method Cont’d
 Promotion of Awareness and Compliance for
Artisanal miners and their community is also
recommended.
 The transfer of emerging technology for mercury free
method of mining is desirable; however, it should be
with effective training of end-users.
 The Federal Government of Nigeria need to
formulate a law, if not already in place, that prevents
importation or production of mercury
Strategic Plans to Introducing Mercury
Free Method Cont’d
 The artisanal miners should be organized under a relevant
cooperative society to enable them access microcredit loans
and access government benefits
 The Federal Government of Nigeria need to formulate a
law, if not already in place, that prevents importation or
production of mercury
 These artisanal miners should be organized under a
relevant cooperative society to enable them access
microcredit loans and access government benefits
 This will enable them carry out safe and environmentally
friendly mining operations.
Conclusion
 The paper conclude that artisanal gold mining in
Nigeria can undergo a revolution that can lead to the
birth of a modern and environmentally friendly
method of mining for the benefits of ASM operators,
the Governments and the communities where gold
mining operations is taken place.
 In addition, with the conscious efforts of Federal
government and State Governments in the gold
mineral zones showing interest and soliciting for
partnership with well meaning investors in gold
mining, there is a good indication that gold mining
in Nigeria is about to witness a revolution in the
right direction.
THE END
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