The Range of Environmental Concerns - Mining and the Environment: From Ore to Metal - page 547

Pump

Water to
Separator
for Disposal

Gas to
Pipeline

Water Production Rate

Stable
Production
Stage

Dewatering
Stage

Decline Stage

FIGURE 13.12
Relationship of Dewatering and
Methane Release Over Time

soils and crop yields, and the factors that inl uence those effects are not completely under-
stood. Hydrologic changes resulting from CBM operations may adversely affect i sheries;
the nature and extent of those effects, however, are largely unknown. Coal seam dewater-
ing can also affect the shallow groundwater table, impacting shallow bores, springs and
domestic wells.
Roads and equipment used to recover CBM may fragment the habitat. A large number
of wells have to be drilled, and access to these wells needs to be provided. Vehicles operating
on area roads, compressors, drilling and water-pumping equipment generate noise that can
be constant and at sound levels higher than normal. The most signii cant sources are large
compressor sites containing two or more compressors, fuelled by large diesel or natural
gas engines. Noise can negatively affect wildlife and impair the quality of life for humans.
Negative visual impacts can result from areas cleared for development or eroded by CBM-
produced water discharges and by CBM equipment, buildings, roads and power lines.
On the regulatory side the main concern is that relatively few CBM-specii c regulations
have been written. Typically, CBM operators must comply with regulations applicable to
other oil and gas drilling and production operations, but other regulations including min-
ing regulations may also become relevant, potentially being in conl ict with each other.

CBM-produced water can contain con-
centrations of sodium, total dissolved
solids, total suspended solids, fl uoride,
chloride, ammonia and metals higher
than those of the receiving waters.

13.6 BIODIVERSITY AND HABITATS

The most obvious impact to biodiversity from mining is the removal of vegetation, which
in turn alters the availability of food and shelter for wildlife. Mine waste placement areas
conventionally occupy large areas, and yet almost all the world's supplies of metallic min-
erals to date have come from only about 4,000 square kilometres of the Earth's surface
(Pearl 1973). This accounts for less than 0.003% of the total land area. This number may
have changed since then but it will be small nevertheless.
In a wider sense mining may impact biodiversity by changing species composition and
structure and, in some cases, by providing access to previously isolated wilderness areas
enabling exploitation of biological resources in areas where this was previously impossible
( Figure 13.13 ). Acid drainage and high metal concentrations in rivers, for example, gen-
erally result in an impoverished aquatic environment. Some species of algae and inverte-
brates are more tolerant of high metals and acid exposure and may, in fact, thrive in less

Mine waste placement areas
conventionally occupy large areas,
and yet almost all the world's
supplies of metallic minerals to
date have come from only about
4,000 square kilometres of the
Earth's surface.