A guide to leading practice sustainable development in mining

Mercury for gold recovery in small/artisanal operations. In other operations,
workplace concentrations of mercury should be monitored routinely
where exposure is possible, for example due to thermal desorption of
metallic mercury. This can occur when ores (some zinc concentrates, for
example) containing trace amounts of mercury are roasted. A case study
of reduction of mercury pollution that could arise from artisanal mining is
presented in the handbook Risk Assessment and Management. Assistance
from the mining company operating nearby is provided under the United
Nations Industrial Development Organisation Global Mercury Project.
Metals as ions or complexes from Copper, Lead, Zinc, Nickel, Iron, Arsenic,
Mercury and Cadmium sludges or solutions. Recovery of the metal is
usually the object of the mining project but hazards may arise from
the presence of toxic by-products (arsenic and cadmium for example)
or metals released as a result of developing acidification, as described
in the handbook Managing Acid and Metalliferous Drainage.
Thiosulfates, polythionates, also resulting from acid mine water or
processing solutions. Sodium dithionite generates sulfur dioxide
in solution and may be stored on minesites as an alternative to
gaseous sulfur dioxide. Accidental wetting of dithionite leads to an
exothermic process that may produce sulfur dioxide fumes.
Process reagents (acids, alkalis, frothers and collectors, modifiers, flocculants
and coagulants which contain aluminium and iron salts and organic polymers.
Recourse needs to be made to Material Safety Data Sheets for these
substances for information that can lead to best practice management.
Nitrogen compounds from blasting materials. In enclosed spaces the
combustion products from nitrate explosives, predominantly ANFO at present,
need to be dispersed before work can restart in the affected area. Best
practice consists in adequate ventilation and monitoring of the workplace
atmosphere, rather than the use of personal protective equipment.
Oil and fuel used for engines, power plants, and lubrication. Although
hydrocarbon products may cause dermatitis when skin is contacted, the main
hazard is one of fire. Because considerable quantities of hydrocarbons may be
stored on a minesite, their presence also constitutes a security hazard because
they could be targeted in an attack. There are also the potential impacts on
the environment from spills, storage tank leakage and accidental discharge.
Suspended soils, mine water, surface drainage and process effluents.
State and Territory regulations cover discharges to watersheds and water
bodies, but best practice should go beyond mere compliance and seek
opportunities to avoid environmental damage and to improve water quality.
108 LEADING PRACTICE SUSTAINABLE DEVELOPMENT PROGRAM FOR THE MINING INDUSTRY