The Range of Environmental Concerns - Mining and the Environment: From Ore to Metal - page 551

species extinctions than land uses such as agriculture, plantation forestry or urbanization,
which involve much larger areas (see also Case 7.5 ). In fact, perhaps the major concern is
the cumulative impact of mining, together with other changes in land use.
Occasionally, there may be specialized habitats coni ned to sites where ore bodies
intersect the ground surface. If all such ore bodies were to be mined, then all these sites
would be destroyed, together with any species coni ned to these habitats. Such a situation
appears to be behind a recent recommendation by the Environment Protection Authority
of Western Australia to disallow mining of the Mesa 'A' and Warramboo iron deposits
of the Robe River Project. Here, the concern was the perceived threat to the continued
existence of 11 previously unknown species of small (4 mm) spider-like invertebrates that
live in cavities and crevices in the rock at depths of 5 m to 30 m below the surface. The iron
ore has a particularly i ssured and honeycombed structure and is habitat to an apparently
unique assemblage of subterranean organisms termed 'Troglobitic fauna'. (It should also
be noted that most rock formations have never been investigated for such organisms).
Perhaps the most vulnerable ecosystems and habitats occur in freshwater aquatic envi-
ronments (wetlands) downstream of major sulphide ore bodies. In these cases, there is the
potential that either accidental discharges during operations, or acid rock drainage from the
mine, waste dumps or tailings facility could contaminate the water downstream, killing
many of the resident species. The long-term degradation of aquatic habitats in the King
and Queen Rivers of western Tasmania which resulted from dumping of mine wastes from
the Mt Lyell copper mine and other mines over many decades, is an example of extensive
habitat damage, affecting much of a river system. However, unless the rivers involved
contained endemic species, biodiversity except at the genetic level, would not have been
affected.
From the foregoing, it is clear that there are situations in which the survival of par-
ticular species may potentially be threatened by mining. However, such situations are rela-
tively uncommon; many mining operations pose no threat to any plant or animal species,
although they may cause some loss of genetic diversity.

Perhaps the most vulnerable
ecosystems and habitats occur in
freshwater aquatic environments
(wetlands) downstream of major
sulphide ore bodies.

Indirect Effects - Introduction of Weeds and Pests

Introduced plants and animals pose a much greater threat to biodiversity than the direct
effects of mining. While at i rst glance it may seem unlikely that a mining project could
introduce weeds or pests, there are several mechanisms by which this does occur. These
include:
1. Ballast water disposal. Most major mining projects involve shipping of mineral products,

often from dedicated port facilities. Ships used for transport of bulk minerals must i rst
discharge water from ballast tanks, the water having originated at another port, often
located a great distance away and sometimes in a different ocean. There have been many
worldwide examples of marine species introduced in this way and invading their new
habitats to the detriment of native species. According to the CSIRO (1993), as one exam-
ple, more than 100 marine species have been introduced in this way to Australian waters.

Any non-native species
being considered for mine
rehabilitation should be carefully
trialled and closely monitored
prior to its introduction.

2. Rehabilitation. Weeds may be introduced deliberately or inadvertently. Some species

that are not invasive in their natural habitats, prove to be highly invasive when intro-
duced to a new area. This is the case with many of the worst weeds throughout the
world. Any non-native species being considered for mine rehabilitation should there-
fore be carefully trialled and closely monitored prior to its introduction. The advan-
tages and disadvantages of using non-native species for rehabilitation are discussed
in more detail in Chapter Twenty-One. Inadvertent weed introduction can occur