Marcelo Gontijo

7/30/2019 Marcelo Gontijo

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Advanced control of crushing and

autogenous grinding circuits using

image analysis

CEMI Process Technology and Engineering

Minas Gerais, Brazil


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Objectives

Demonstrate tools applicability for advanced

process control and online particle size image

analysis in crushing and autogenous grinding

c rcu ts


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Advanced Process Control (APC)

PLC/DCS

APC

Control Room

OperatorProcess


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Differentiation

Manual Control Regulatory Control Advanced Control


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Manual Control

High variability;

Process operated far from ideal economic point.


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Regulatory Control

Low variability

Process operated far from ideal economic point.


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Advanced Control

Low variability

Process operated close to ideal economic point.


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Advanced Control Techniques

Expert System/Fuzzy Logic;

MPC (Model Predictive Control);

eura etwor .


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Advantages: Expert System/Fuzzy Logic

Avoid difficulties obtaining a trustable model

(MPC) or trustable data (Neural Network);

Easy to deal with data from online sampling

analysers and laboratory analysis;

Easy to track/debug system actions.


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Vision Systems

There are systems that use image analysis to infer

ore size distribution curve, an important

measurement for crushing and autogenous

grinding process.


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Up To Date Vision Systems Features

OPC communication, allowing easy interface with

PLC, DCS, PIMS and APC systems;

IP Network Cameras;

Multiple cameras processing simultaneously;

Led Lighting.


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Hardware

Network HD Camera

with remote zoom

and focus and IP 66protection

Led lighting has a

lifetime of more than

50000 hours and lowenergy consumption


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Hardware


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Architeture


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Vale Mutuca Flowsheet


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Crushing Controlled Variables

BR-02/BR-03 Chamber level;

BR-02/BR-03 Power;

BR-02/BR-03 Vibration;

BR-02/BR-03 Product Size Distribution (available

from Vision System);

TC-04 (Circulation Load) Mass flow rate.


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Crushing Manipulated Variables

TC-03 (Fresh Feed) Mass Flow Rate;

BR-02/BR-03 Opening/Closing teeth.

Variables to define how and when to act in each

Manipulated Variable.


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Crushing Results

Project at Vale Mutuca is still in progress, a similar

application was performed in 2008 at RPM/Kinross

Gold Corporation in Paracatu, Minas Gerais, Brazil.

Feed particle size (F80) reduced from 13mm to

11.2mm, representing an increase of 100.000

tons/year, payback in 6 months.


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SAG/AG Grinding Flowsheet


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SAG/AG Grinding Controlled Variables

TC-01 Product Size Distribution (available from

Vision System);

AL-01/AL-02/AL-03 Product Size Distribution

(available from Vision System).


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SAG/AG Grinding Manipulated Variables

AL-01/AL-02/AL-03 Feeders speed

Due to the effect of particle segregation, feeders

under the extremes of stock pile are supposed to

operate with coarser material compared to central

feeder.


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SAG/AG Grinding

AL-02 (Feeder under pile center) has

speed increased and AL-03 (Feeder

under pile extreme) is stopped.


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SAG/AG Grinding

TC-01 Vision System detects increase in fines

amount and reduction in coarse fraction.


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SAG/AG Grinding

SAG noise increased, confirming

that material became finer.


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Conclusion

The use of image analysis tool combined with

expert fuzzy logic system are suitable to crushingand autogenous grinding circuits.


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Conclusion

The expected improvements are:

Capacity optimization of ore processing;

Process stability;

Increase average production;

Increase efficiency of the circuit.

Marcelo Gontijo

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