Environmental Engineering Reference
In-Depth Information
Gregory 1981; or
www.geology.com
). Most mining terms in this textbook are introduced
selectively, but a few key terms are defined below.
Mining is defined as all activities related to excavating rocks, stones, or minerals that
can be sold at a profit. In a more general sense it also includes the subsequent extraction
of valuable metals. The extraction of valuable minerals and further refining is referred to
as mineral processing, detailed in the following section. Mineral processing covers a wide
range of metallurgical processes, ranging from simple gravimetrical separation to complex
high-pressure acid leaching to smelting. Primary mineral processing is commonly based
on physical processes, referred to as ore beneficiation. Beneficiation is an integral part of
many mining operations.
The excavation made into the Earth-crust to extract minerals is called the mine. The
mined mineral itself is a naturally occurring substance, usually inorganic (coal, the most
obvious exception, is an organic compound), having a definite chemical composition and
distinctive physical characteristics.
Unique mining terms and expressions impose unexpected challenges in working on
mining projects in countries with a relatively young mining history. Often no equivalent
for a specific mining term exists in the local language, which makes the preparation of
documents such as environmental impact statements challenging. It is not uncommon for
English mining-specific terms, such as tailings, to be adopted in many languages and even
to become part of national mining legislation (e.g. Ind. Government Regulation 19 of 1994).
Mining is defi ned as all activities
related to excavating rocks,
stones, or minerals that can be
sold at a profi t.
1.2 THE PATH OF MINERALS FROM CRADLE TO GRAVE
Mining is only the first step in the minerals cycle, that is, the path of any given mineral
from cradle to grave. The concept of conducting a detailed examination of the life-cycle of
natural resource use, a product, or a process is relatively recent, having emerged in response
to increased environmental awareness. The immediate precursors of life-cycle analysis and
assessment were the global modelling studies and energy audits of the late 1960s and early
1970s, which were attempts to assess the resource cost and environmental implications of
different patterns of human behaviour. Life-cycle analyses were an obvious extension, and
they are now vital to the evaluation of mineral use, from mining to the manufacturing
processes, the energy consumption in manufacture and use, and the amount and type of
waste generated. The study of minerals cycles is instrumental in accurately assessing the
total burden placed on the environment by natural resource use. A number of different
terms have been coined to describe life-cycle analysis, such as Life Cycle Inventory, Life
Cycle Assessment, Cradle to Grave Analysis, Eco-balancing, or Material Flow Analysis.
Whichever name is used, life-cycle analysis is a potentially powerful tool, which can
improve understanding of the environmental consequences of mineral use.
Minerals Cycle
Minerals are natural resources which are essentially non-renewable, a term applied to
resources whose natural regeneration cycle is extremely long. Minerals, metal ores, fossil fuels,
and soils do regenerate, but this regeneration takes thousands or millions of years. As a result,
non-renewable resources are generally regarded as finite, and their consumption as 'irrevers-
ible', a concept underlying the minerals cycle in our economy as depicted in
Figure 1.2
.
Minerals are extracted, transformed into products and goods, transported to other parts of
the world, recycled and, sooner or later, released back to the natural environment as waste or
Minerals are natural resources
which are essentially non-
renewable, a term applied
to resources whose natural
regeneration cycle is extremely
long.
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