Introduction - Advanced Control and Supervision of Mineral Processing Plants - page 7

Tabl e 1. 1 Geological factors and their effect on metallurgical operations [10]

Geological/mineralogical factor Area of linkage Metallurgical operation

Primary rock type and size distribution Hardness Crushing, Grinding

Ore assemblage and ore formation Solubility, Hardness, Grinding, Flotation

Presence of talc

Alteration Clays, hardness Grinding, S/L separation

Down temperature (Hypogene) Clay, oxidation Flotation

Faulting Clay, presence of talc Grinding, S/L separation

Metamorphism Hardness Flotation

rock structure, rock strength, blast intensity and primary crushing. In the area of
mineral separation, some examples dealing with the coordination of grinding and
flotation stages have also been presented [13, 14].
As pointed out by Hodouin [15] the task of devising a global coordinating strat-
egy has been hampered by a lack of liberation measurement and reliable models.
However, the idea of integrating the operation of all the processes remains the ulti-
mate goal of a mineral processing automation system.

1.3 Main Functions of Automation Systems in Mineral
Processing Plants

The main goal of an automation system is to provide timely information and to take
prompt actions to ensure a safe and stable operation in spite of the external and in-
ternal disturbances affecting the process. In order to accomplish these objectives,
the automation system requires the carrying out of a set of functions, which can be
divided into two categories: basic and advanced functions. The former are funda-
mental functions essential to any automation system for controlling or monitoring a
process. The advanced functions, which require the implementation of the previous
functions, are oriented to the analysis of information and to the higher decision-
making process.

1.3.1 Basic Functions

1. Human-machine interface (HMI). In modern automation systems, operators are
located in a room away from the process. Consequently, the interaction between
the automation system and the operator plays an important role in ensuring an
effective operation. Timely presentation to the operators of relevant information
regarding both normal and abnormal process states is of prime importance for
the success of the automation system, and for its acceptance by them. Compli-