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Environmental, Health and Safety aspects of gold mining
Health & Safety
aspects
Environment
aspects
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Environment
aspects
Mining operations focus on minimising environmental effects in the
short-, medium- and long-term. This means that sites are not only
designed to have the minimum impact during operation, but also the
closure and after-care of the site is planned from the out-set.
Environmental Impact Assessments (EIA), Risk Assessment evaluations,
biodiversity action plans, integrated closure plans and monitoring and
follow-up are just some of the strategic tools routinely applied by the
industry to minimise environmental effects. Environmental audits are
regularly conducted to review and constantly improve the environmental
management at each site, which has been demonstrated by many projects
within the EU to be world-class.
Leaching of gold with sodium cyanide solutions is controlled by
specific safety measures to prevent incidents and environmental
impacts. The design of a cyanide leaching plant includes a thorough
Risk Assessment where technical solutions aimed at the prevention of
accidents and environmental impacts are identified, implemented and
insured.
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To prevent any impact on the environment
and on the Health &
Safety of operators, new mines are and will be complying to limit
values below international standards due to the presence of design
features such as the following:
- The incorporation of a
cyanide destruction circuit before tailings are
placed into tailings ponds.
- Secondary containment of
leach-tanks to collect any accidental
spillages
- Connection of indoor
equipment to a gas extraction system with a
scrubber operating with NaOH- solution.
- Backup power generators are
installed.
- Any spills are pumped back to
the circuit.
- Well educated and trained
operators run the operation.
- Strict environmental
monitoring of the entire site is applied.
- Strict Health &
Safety routines.
- Strict management procedures
for leachate.
- Strict management of
chemicals.
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At all sites in Europe where tank leaching
is practised, the effluent (tailings and tailings water) undergoes
cyanide destruction prior to discharge into the tailings pond. The
treatment results are very satisfactory. Nevertheless, the water
quality in the tailings pond is also frequently monitored and analysed
for cyanide concentration as well as other components such as heavy
metals, pH and conductivity.
The physical stability of the tailings pond is guaranteed using
conservative design, careful quality control during construction,
proper management during operation, monitoring and control, dam safety
audits and a proper closure at the end of its operational period.
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European
obligations
All waste resulting from the extraction
and mechanical, physical, biological, thermal or chemical processes
carried out on gold ores, including leaching, and the re-processing of
previously discarded waste, is covered by the Mine Waste Directive,
which requires;
- a Waste Management Plan,
- a Waste Management Permit,
- Public Consultation during the
permitting process,
- minimum competence, development
and training of staff,
- prevention of pollution of soil,
air, groundwater & surface water,
- reporting of any events likely to
affect the stability of the waste, or cause significant environmental
damage within 48 hours,
- certified closure of the tailings
facility at the end of the mine’s life,
- monitoring of the tailings
facility after closure,
- CEN or ISO standards for sampling
and analysis,
- adequate measures to prevent or
reduce gas emissions,
- financial guarantee of
rehabilitation of any land affected by the waste facility at any given
time,
- regular inspection of the
tailings facility by the competent authority.
- the lowest possible concentration
of weak acid dissociable cyanide in ponds to a maximum level of 10ppm
using BAT. BAT is to do the following:
- reduce the use of CN by applying:
- operational strategies to
minimise cyanide addition
- automatic cyanide control
- if applicable, peroxide
pre-treatment
- destroy the remaining free CN
prior to discharge in the pond
- apply the following safety
measures:
- size the cyanide destruction
circuit with a capacity twice the actual requirement
- install a backup system for
lime addition
- install backup power
generators.
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In
2008 the European Union finalised specific mine waste legislation,
which includes the world’s strictest limit values for cyanide, as
well as a Best Available Technology document (BAT), which provides
recommendations for legislators and industry in handling cyanide. The
industry fully supports their implementation.
Europe represents a modern and developed society, with technologies and
wealth to a large extent relying on the benefits of metals, including
gold. EU mines are required to operate at world-class standard with
respect to sustainability criteria, i.e. environmental protection,
economical performance and social development. Therefore, it is
Euromines’ opinion, that EU Member States have a
responsibility to support their demand for gold and other metals by
supporting the EU’s own mineral extraction and processing
industry according to its own strict standards.
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