Identifying and Evaluating Impacts - Mining and the Environment: From Ore to Metal - page 403

FIGURE 9.3
Cross Media Impacts

Project activities

Source:
Based on ADB 2003

Human
environment

Economic
environment

Physio-chemical
and biological
environment

impacts. These impacts are often subtle, and difi cult to identify and measure. For exam-
ple mining may cause a direct change in groundwater level, thereby affecting a nearby
wetland with impacts on its plants and animals. Induced development due to mining and
most other social impacts are examples of indirect impacts.
Induced development (e.g. population increase and related environmental impacts)
does not always receive scrutiny in environmental assessment because it is accepted that it
just happens. Good practice, however, requires that induced development be considered
in impact assessment if there is reason to believe it may occur. Ultimately, because of the
uncertainty and often dispersed nature of induced development and related activities (i.e.
activities may occur in many places within the host region under different jurisdictions),
induced activities are best considered as part of regional development planning, involving
regional administrative authorities.
Impacts on a particular environmental medium frequently affect other media (sometimes
referred to as cross media impacts, Figure 9.3 ). Indirect impacts often outnumber direct
impacts and tend to be more signii cant. An increase in noise level, for example, may have
an effect on nesting birds. While the direct impact of increased noise may not qualify as sig-
nii cant using simple assessment methods, indirect impacts from this on the ecology may be
signii cant. Similarly, an increase in mine production may generate only a limited number of
actual employment opportunities. Doubling mine production, for example, may generate the
perception of doubling working opportunities. This perceived prospect of employment will
attract migrants to the area which in turn can place stress on local communities and public
infrastructure, imposing social challenges on the mine, and the local government. In such
cases, in the absence of indirect impact analysis, employment opportunities may be classii ed
as presenting signii cant benei ts, while related indirect negative impacts are severe.
Cumulative impacts are mostly indirect impacts, and are dei ned as incremental environ-
mental changes caused by independent or repetitive activities. These impacts may occur as
interactions between activities, between an activity and the environment, and across environ-
ment media. Cumulative effects can occur in many ways (CEAA 2003; Spalding 1994): (1)
A physical or chemical constituent can be transported away from the impact source only to
interact with another activity or environmental medium (e.g. soil erosion or acid rock drain-
age). (2) The gradual disturbance and loss of land and habitat, or nibbling loss (e.g. incre-
mental land clearing as the mine advances or incremental road development into forest areas,
alienating wildlife habitat due to sensory disturbances). (3) Spatial and temporal crowd-
ing, when too much is happening within too small an area and/or in too brief a period.

Induced development does
not always receive scrutiny
in environmental assessment
because it is accepted that it just
happens.

Spatial and temporal crowding,
when too much is happening
within too small an area and/or
in too brief a period.