Identifying and Evaluating Impacts - Mining and the Environment: From Ore to Metal - page 409

TABLE 9.5
Ranking of Effects based on Effect's Attributes

Duration Magnitude Extent

Local Regional Territorial National

Short-term Low L L M M

Short-term Moderate/high L M M M

Medium-term Low M M M M

Medium-term Moderate/high M M M H

Long-term Low M M H H

Long-term Moderate/high M H H H

(A ranking of L (Low), M (Moderate), or H (High) is determined based on the duration, magnitude and extent of an effect)

knowledge of local conditions, or insensitivity towards community opinions. Objectivity
facilitates a fair comparison of the impacts between project alternatives. In an ideal world,
impact evaluation would contain no bias.
Is the method comprehensive? Accuracy and completeness require a method capable of
detecting the full range of potential effects, directing attention not only to obvious impacts,
but also to novel or unsuspected ones ( Case 9.3 ).

CASE 9.3
Ecological Risk Assessment Study of the
Freeport Tailings Disposal Scheme

The Ecological Risk Assessment study to support the
environmental permitting of riverine tailings disposal
of the Freeport Copper and Gold Mine in Papua, East
Indonesia arguably constitutes an extreme case of assessing
environmental change and associated consequences in a
comprehensive fashion, fully justifi ed by the complexity of
the tailings disposal scheme, and the controversy that goes
with it. The study took several years to complete, engaging
a wide range of task specialists, from modellers to toxi-
cologists, and is based on several thousands of fi eld data
(Jakarta Post, April 2006).