Page 281 - Materials Chemistry, Second Edition

APPLICATION OF LCA IN MINING AND MINERALS PROCESSING 269

chain (see [1]). However, more recent work has highlighted that the environ-
mental impacts of the mining and minerals processing sectors are not always
adequately reflected in LCA work (discussed later in this chapter). Further, if
the life span of the product is adequately considered then the impacts associ-
ated with the use phase dominate more often than not (e.g. electrical goods,
cars, buildings). As a rule of thumb, short-life, disposable products are domi-
nated by the production and manufacturing stages of the life cycle (aluminium
foil), while energy consuming long-life products are dominated by the use
phase (aluminium windows).
A more detailed review shows the role that the functional unit, and ulti-
mately the goal of the study, plays in defining the impact of different mate-
rials and different life cycle stages on the total impact of the system. A case
in point here is the difference between the environmental impact of produc-
ing a brick, the environmental impact of producing a surface area of wall, the
environmental impact of producing a house, and the environmental impact of
providing a family with shelter. Ultimately the intention of LCA is to assess
the environmental impact of a service or product, in this context the impact of
the use phase can dominate. As the functional unit tends away from specific
products and towards services, the impacts of production become diluted and
the impacts of use begin to dominate.
This leads to the realisation that, while environmentally intensive, mining and
minerals processing typically do not represent the most significant impact stages
of service or product life cycles. It was this misconception about the mining sec-
tor which resulted in many companies not being prepared to supply informa-
tion to LCI databases internationally Increasingly we are seeing companies being
willing to supply more accurate information to LCI processes, however typically
through industry associations and as industry average information, not on a com-
pany by company basis (examples are Worldsteel/IISI, International Aluminium
Institute, etc.). A classic example of a product where the use phase dominates is
the role of bricks in a house. This is illustrated in Figure 12.1. Typical observa-
tions on the impacts of different life cycle stages for different product types are
included in Table 12.1. Details of the materials illustrated in this figure are:

• Metallic, long life: steel in construction, aluminium in cars and
construction, copper in white goods
• Metallic, short life: aluminium and steel in packaging
• Non-metallic, functional: construction materials
• Non-metallic, decorative: gem stones and precious stones
• Energy carriers: coal, oil, gas

The mining and minerals industry has little influence on how, or sometimes
even where, its products are used. International commodity exchanges repre-
sent a disjunct in the value chain of materials - markets set prices making the
industry price takers as opposed to price makers, and they enable buyers to be
completely divorced from the producers of the raw material they are purchas-
ing. Typically companies (virtually) aggregate their products and sell them on