Introduction - Advanced Control and Supervision of Mineral Processing Plants - page 11

istence and mathematical models were developed. The availability of such models
and the increased capability of digital computers provided new impetus for the de-
velopment of control strategies aiming at simultaneously controlling several pieces
of equipment to pursue an overall control objective.
In the 1980s, almost all large- and medium-sized mineral processing plants
worldwide implemented some form of automatic control involving the use of a num-
ber of stabilizing control loops. The technology was a mixture of analog and digital
controllers. During this decade, plants adopted many newly developed sensors to
measure the main process variables, which were processed through distributed con-
trol systems [19, 20].
The 1990s brought a wider industrial acceptance of advanced technologies, for
instance, the use of advanced control strategies based on expert systems applied
to SAG mill circuits. Data management systems were also implemented for col-
lecting and storing operating data from almost all plant-units in a unique database.
The enhanced data availability and the existence of friendlier systems for access-
ing it improved process accountability. In addition, this led to the development of
data reconciliation algorithms and multivariable data analysis techniques for process
monitoring. The use of vision-based sensors for particle size distribution measure-
ment and froth image analysis also extended to almost all medium- and large-size
installations [15].
Finally, since 2000 the industry has witnessed an increase in the number of ac-
tivities using image-based measurements, artificial-intelligence applications to unit
supervision and the use of multivariable non-linear control of flotation systems.
Future developments will likely include an integrated plant operation, coordi-
nating the operation of the different units aimed at increasing the overall benefit
level. The coordination of these units will also have an impact on how the plant is
operated.

Real-time Information systems
Data reconciliation
Process monitoring

Plant

Process

Expert systems
Distributed control systems

Unit

Digital control

Advanced maesurements

Equipment

Basic measurements
Analog control loops

70's 90's

90s

00's

00s

60's

60s 70s

80's

80s

decades

Figure 1.4 Evolution of the automation system in mineral processing