1100 implementation of advanced flotation control at … · implementation of advanced flotation...

Implementation of Advanced Flotation Control at First Quantum Minerals’ Kevitsa Mine

A.Rantala, I.Muzinda, J.Timperi, C.Cruickshank, O.Haavisto

12th AusIMM Mill Operators’ ConferenceTownsville September 1-3 2014

© Outotec – All rights reserved

Outline

• Introduction• Process control• Grade-recovery optimisation• Design of plant trials• Results• Conclusions• Acknowledgements


FQM Kevitsa Mine

• Open pit mine located at northern Finland• Ni ~0.2%, Cu ~0.3%, PGEs• Ramp up Q2 / 2012

• 2013 Production*• 6.3 Mt ore processed• Ni 8,963 t, Cu 14,775 t• Ni-Cu-PGE-Au concentrate (~12 % Ni)• Cu-PGE-Au concentrate (~28% Cu)

• Process• Crushing• AG and ball mill grinding• Cu, Ni, S flotation• Dewatering

*http://www.first-quantum.com/Our-Business/operating-mines/Kevitsa/default.aspx


Flotation Flow Sheet


Process Control

• High level of process control

• Objectives• Safe operation of the plant• Operator support and information management• Stabilisation and optimisation

• Key Systems• Instruments• Analysers and sampling• Process Control System• Advanced process control• Information management


System Diagram


Grade-Recovery Optimisation• Stabilisation

• EXACT feedforward level controller• FrothSense froth speed control

• Optimisation• ACT Grade-Recovery optimizer• Rule base logic and state matrix• Open parameters

• Philosophy• Open box for the operators• Identify ore feed changes• Operate froth speed and reagent

profiles based on the process state• Delimiters and abnormal state

management


ACT Parameters Page


Grade Control


Design of Plant Trials

• Bottom to top approach

• The effect of EXACT and froth speed control to stability and daily operator work

• The effect of ACT control to Cu circuit recovery and grade• On-stream analyser assays used in the

study after validation against laboratory


Validation of On-Stream Analyser

0.00

0.10

0.20

0.30

0.40

0.50

0.60

Feed Cu% Lab

Feed Cu% Courier

Tails Cu% Lab

Tails Cu% Courier


Validation of On-Stream Analyser

Cu Recovery Courier

Cu Recovery Lab


Slurry Level Control

1st Rougher level

2nd Rougher level

1st Scavenger level

Feed flow


Froth Speed Stabilisation

0

2

4

6

8

10

12

14

16

18

Cu Rougher 1/2 Cu Rougher 3/4

Froth Speed PV-SP avg error mm/s

EXACT ON EXACT OFF


Grade-Recovery Optimisation


Results SummaryACT

controlCu conc. grade

(%)Cu recovery*

(%)Feed Cu

(%)Flotation feed(dry tonnes)

AverageON 26.13 71.35 0.33 803

OFF 25.32 70.04 0.33 817

Standarddeviation

ON 0.76 2.59 0.05 39.01

OFF 1.64 3.99 0.04 30.38

Number of samples(hours)

ON 29 29 29 29

OFF 41 41 41 41

p-value 0.003** 0.050** 0.804*** 0.107***

Confidence level 99.7% 95% Not significant

Not significant

* Excluding the Ni circuit Cu recovery **Welch’s test, one tailed *** Student’s t-test, equal variances assumed, two tailed


Conclusions

• Efficient treatment of variable and low grade ore body at FQM Kevitsa Mine benefits from the high level of process control

• ACT Flotation optimization at copper circuit increased recovery by 1.3% with higher copper grade, which corresponds roughly 200 tonnes of copper at annual level

• Feedforward level control and froth speed control increase the stability and controllability of flotation allowing operators to focus more on the process itself


Acknowledgements

FQM Kevitsa Mine is greatly acknowledged by approving and supporting the research study, publishing of the results and for the long term co-operation. Also the team of advanced process control specialists, especially Jukka Martikainen and Mika Etelapaa, and metallurgists, operations management and operators of FQM Kevitsa Mine are acknowledged for the commitment and contribution to the achieved results

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