Declining metal prices over the last few years have reduced
the number of new metallurgical plants being built and limited opportunities for
introducing new processes. However, technological advances are still being made.
With increasing economic pressures, the emphasis is now on reducing unit costs
by making equipment larger and through use of technologies with lower operating
costs. This trend can be seen in the increasing size of grinding mills and
flotation cells used in recent plant designs and in the adoption of HPGR
crushing as an alternative to SAG milling.
Few new technologies achieve
widespread introduction until there are clear economic or operational drivers.
These might currently include:

increasingly stringent
environmental standards;

availability of exotic materials
for equipment construction;

increasingly sophisticated
instrumentation and control systems;

the
need to treat increasingly refractory oretypes; and

the
length of supply routes to many new plants.
As a result of these drivers, a
number of new and revitalised technologies will get increasing prominence in the
design of new operations, such as:

use of
ultrafine milling equipment such as MIM's Isamill for treatment of refractory
gold ore concentrates;

use of
thiourea as an alternative for cyanide in sensitive
locations;

novel
hydrometallurgical routes for treating base metal ores in remote
locations;

paste
thickening for tailings deposition; and intensive
cyanidation of gravity concentrate