Minerals Processing

The minerals processing enterprises are widely using vibrating machines to separate different fractions of materials. Sieving efficiency is greatly dependent on particle trajectories, or orbit, of periodical motion over the sieving decks. A screening process is very dependable on design parameters such as the vibrator power, synchronisation of their drives, and oscillation frequency as well as the stiffness of supporting springs. Deterioration of supporting springs (stiffness reduction and cracks) due to cyclic loading and fatigue is difficult to determine by the visual inspection, static loading tests, or nondestructive testing techniques. Vibration monitoring systems of different vendors are analysed where vibration sensors usually installed on the bearings of vibrators are as well used for supporting springs diagnostics. However, strong cyclic components from the unbalanced exciters and stochastic disturbances from the input stream and vibrating pieces of the material make analysis a not trivial task. e considered vibrating screen is investigated on the 6-DOF (degree-of-freedom) dynamical model to reflect all linear and rotational components of spatial motion. Besides the main periodic motion, the model accounts for stochastic alpha-stable distributed impacts from the material. Instead, the Gaussian normal distribution is considered for the position of equivalent force application point. Supporting springs are represented by the bilinear stiffness characteristics. Specific features of vibration signals (angle of orbit inclination, natural frequency change, harmonics of natural frequency, and phase space plots) are analysed to recognise the weak nonlinear features of a system under conditions of small stiffness changes in springs. e extensive measurements are conducted on the industrial vibrating screen, and the dynamic model is verified by the measurement data. Recommendations are given on failure diagnostics of springs in the industrial vibrating screens.

INTRODUCTION
Sustainable development, or SD, as usually it is referred to, is a concept, in reality, a “working concept” proposed by BRUNDTLAND in her excellent 1987 UN report, best known as “Our Common Future”, readily available at the internet for reading.
Little by little, as in “baby steps”, forward, sometimes, the defined and involved stakeholders in promoting SD had taken actions towards the effective and achievable goals therein proposed.
Indicators for SD are available in the literature and at the internet in several formats, depending on the particular issue of “sustainability” that one is addressing to. Overall indicators, and their discussions on uses and abuses as well as applications, are the objects of the “goals of the millennia” events, best known as” Rio+10” and “Rio+20”!
Since SD is a WORKING concept, it changes and adapts as time passes and today it is well recognized that the application, and revision, of SD is rather for a “region” in a space, rather than a “point” in a space, as several stakeholders were addressing the issue in the 90´s!
As for the mineral based industries, SD challenges are in MINIMIZING MASSES – water included -, MINIMIZING ENERGY – searching for alternative sources as well - , MINIMIZING ENVIRONMENTAL IMPACTS – soil, gases, liquids, landscape, etc.- and ,last but not least MAXIMIZING SOCIAL SATISFACTION – an item where “social license to operate” plays a significant role.
If such is the case, we as scientists and engineers, as mining and mineral processing operators have a lot to contribute to the challenges posed by the three principles of MINIMA and in doing so our collaboration to society on the MAXIMA one will be very much appreciated.
The “IMPC 2014 SUSTAINABILITY STMPOSIUM” was designed to promote ideas, discussions of such ideas, proposals, and discussions of such proposals on specific areas of the FUTURE OF MINING, PROCESS
ENGINEERING & INNOVATION, SOCIAL LICENSE TO OPERATE and SD IN ENGINEERING EDUCATION.
In order to shorten the time gap between the vivid presentations at the Santiago´s IMPC and to allow ready access to these same presentations by the interested parties and stakeholders it was decided to present this “book” in an “internet format”, informal, thus hoping that the minor eventual errors that are still present may compensate the enormous and not readily available time of the presenters to prepare a formal edition.
Thus, in the next pages –or slides- you will find the pdf of the said presentations.
Hoping you all enjoy “reading and seeing” what follows, please accept the warmest regards of the 2014 IMPC Sustainability Symposium coordinators
Rio de Janeiro, November 2014
Roberto C. Villas-Bôas
Chairman IMPC Commission on Sustainability
Emeritus CETEM
Mauricio L. Torem
Professor of Extraction Metallurgy at PUCP-RJ
Editor-in-Chief, International Journal of Mineral Processing, Elsevier
CONTENTS
In the sequence they were presented and discussed. The discussions, unfortunately, are not part of the slides:
ROBIN BATTHERHAM - Progress toward the Sustainable Mine of the Future.
JERRY PERKINS - CAPICHE Project Development in Chile.
HARIKRISHNAM TULSIDAS & ROBERTO C. VILLAS-BÔAS – UNFC and Sustainability in Mining
KAJ JANSSON - Towards Minimum Impact Cu Concentrator: A Conceptual Study.
C.J. KELSEY & J.R.KELLY - New Crushing Concepts
MARKUS REUTER & A. VAN SHAIK - Product Centric Design for Recycling (DfR) - Simulation based prediction of recycling rates and environmental impacts.
FRANCISCO VELLOSO – Trayectoria de ANTOFAGASTA MINERALS: evolución de un compromiso con la sociedad.
DAMARIS FERNANDEZ - The Role of new technologies and new approximations to implement synergic advances within the societal relationship of raw materials industry.
CRISTIAN CIENFUENTES - Challenges in sustainability for the mining project portfolio in Chile
JACQUES V. WIERT - Sustainability education in Chilean undergraduate programs
MARIA JOSE GAZZI SALUM – Eco efficiency concepts and social responsibility in engineering curricula: a Brazilian case.
JENNY BROADHURST, J.P. FRANDISIS, SUE HARRISON, HARRO BLOTTNITZ - Educating Managers and Leaders for Sustainable and Socially Responsible Mining in Africa