The Range of Environmental Concerns - Mining and the Environment: From Ore to Metal - page 540

FIGURE 13.9
The Coal Cycle - From Mining to
Combustion

Gaseous emissions
Ashes
Energy loss

Energy use

The coal cycle differs from the general
mineral cycle in that, following mining, coal is
burnt or converted into other fuels.

Society's need
for coal / energy

Disposal

Consumption

Re-use

Recycling

Incorporation
into products

Exploration

Re-manufacture

Semi-fabrication
and fabrication

Mine
development

Extractive
metallurgy
and refining

Mine closure
and rehabilitation

Extraction
mining

Milling, washing,
grading,
concentrating

Wastes

Emissions

Some industrial
minerals sold directly
(such as salt and sand)

higher prices. Some countries such as Indonesia therefore encourage the export of low sul-
phur coal while using higher sulphur coal for domestic consumption. In the case of oil
this policy leads to the interesting observation that Indonesia produces low sulphur oil for
export, while it imports oil with a high sulphur content for domestic consumption.
NO x emission control is less subject to regulatory standards; in many countries there is
no NO x emission standard for coal-i red power plants. The common method of control-
ling NO x emissions is through combustion modii cation, and generally proves very effec-
tive in reducing emissions. The method relies on the delayed mixing of coal particles in
the combustion air. The use of l ue gas denitrii cation units involves high operating costs
and is coni ned to a few oil-i red power plants. There is insufi cient knowledge about the
health effects and damage to vegetation of long-term exposure to NO x . There is evidence
that NO x is several orders of magnitude less toxic than SO 2 (OECD 1983c).
The release of carbon dioxide is of increasing concern considering that CO 2 plays a
major role in the heat balance of the Earth atmosphere ( Case 13.10 ). A global increase
of CO 2 in the atmosphere causes an increase of the Earth's surface temperature. While
much mining industry rhetoric on climate change relates to improving energy efi -
ciency as one way of tackling greenhouse gas emissions, these future efforts prom-
ise relatively little in terms of the overall reductions required to meet GHG targets. In
the mining sector, the climate change debate is very much concerned with the role of
coal in the industry. And this is not only because coal mining accounts for around two-
thirds of total mining output worldwide (Brendow 2006). UNFCCC estimated glo-
bal CO 2 emissions in 2004 as about 16,797 million tonnes; global mining and quarrying

In the mining sector, the climate
change debate is very much
concerned with the role of coal
in the industry.