Towards more effective simulation of minerals processing systems

Two aspects of the computer simulation of minerals processing systems were investigated in order to facilitate more effective use of simulation technology. A user-interface was designed and combined with an existing simulator executive, resulting in the implementation of a user-friendly microcomputer based minerals processing simulator, MicroSim. Ease of use was achieved by consideration of the needs of the user of such a program. This resulted in the use of graphical methods for information input and output. Efficient form-filling techniques were developed for numerical data entry and editing. Models for the carbon-in-pulp adsorption process and for continuous gold leaching were derived. The CIP models were derived using a population balance approach. The method of characteristics and the method of moments were found to be particularly useful in solving the resulting equations. Besides being important processes in themselves, the integration of these models into MicroSim provided valuable experience regarding the use of such models in a simulator.AC 201

Cosmotopia Delineated: Rammohun Roy, William Adam and the Calcutta Unitarian Committee

This article seeks to establish the value of the concept of cosmotopia to historians of intercultural connections through presenting a case study of the Calcutta Unitarian Committee, which was active between 1821 and 1828. In tandem, it aims to enhance understanding of the origins of one particularly sustained set of intercultural connections: the interfaith network which developed between an influential group of Hindu religious and social reformers, the Brahmo Samaj, and western Unitarian Christians. The article focusses on the collaboration between the two leading figures on the Committee: Rammohun Roy, the renowned founder of the Brahmo Samaj, who is often described as the Father of Modern India; and William Adam, a Scottish Baptist missionary who was condemned as the “second fallen Adam” after his “conversion” to Unitarianism by Rammohun Roy, and who went on to cofound a utopian community in the United States. It explores the Calcutta Unitarian Committee's activities within the cosmopolitan milieu of early colonial Calcutta, and clarifies its role in the emergence of the Brahmo Samaj, in the development of a unique approach to Christian mission among Unitarians, and in laying the foundations of a transnational network whose members were in the vanguard of religious innovation, radical social reform, and debates on the “woman question” in nineteenth-century India, Britain, and the United States. In conclusion, the article draws on the case study to offer some broader reflections on the relationship between utopianism, cosmopolitanism, and colonialism

Finishing the euchromatic sequence of the human genome

The sequence of the human genome encodes the genetic instructions for human physiology, as well as rich information about human evolution. In 2001, the International Human Genome Sequencing Consortium reported a draft sequence of the euchromatic portion of the human genome. Since then, the international collaboration has worked to convert this draft into a genome sequence with high accuracy and nearly complete coverage. Here, we report the result of this finishing process. The current genome sequence (Build 35) contains 2.85 billion nucleotides interrupted by only 341 gaps. It covers ∼99% of the euchromatic genome and is accurate to an error rate of ∼1 event per 100,000 bases. Many of the remaining euchromatic gaps are associated with segmental duplications and will require focused work with new methods. The near-complete sequence, the first for a vertebrate, greatly improves the precision of biological analyses of the human genome including studies of gene number, birth and death. Notably, the human enome seems to encode only 20,000-25,000 protein-coding genes. The genome sequence reported here should serve as a firm foundation for biomedical research in the decades ahead

A new small-scale test to determine flotation performance - Part 1: Overall performance

The majority of flotation models incorporate a parameter that describes the propensity of particles or classes of particles to be recovered through true flotation. This is typically captured in the flotation rate constant or "floatability", and results from complex interactions between particles, solid/liquid/air interfaces and operational variables. Historically, there have been two distinct approaches in determining flotation rate parameters for industrial circuits. Fundamental approaches have focused on mechanisms for quantifying particle-bubble interactions and how these relate to kinetics. The more applied approach, which uses floatability components (grouping of particles that have the same flotation behaviour in terms of rate of recovery), relies on the availability of plant and batch test data, as well as specialised equipment measurements, to back-calculate floatability components or rate parameters, and their distribution in the feed. Since the parameters are derived from experimental data they are only applicable under the specific operating and feed conditions from which they are derived. A third method is emerging which applies mineralogical data to determine the flotation response of individual particles. This is done typically through a Cassie-type approach if the rates of the liberated components are known, or by developing a database of information which relates the flotation response of classes of particles to key mineralogical features. In this paper, a new small-scale test is presented, to compliment current laboratory batch test methods for separability characterisation. Data are presented to demonstrate the comparability of the overall separation achieved in the small-scale test to batch flotation and full scale plant measurements. The small-scale test is shown to be sufficiently sensitive to particle surface attributes, and based on the results presented in this paper, is a good candidate for further development to potentially determining flotation rate parameters. Work in this area is ongoing and will be reported in a subsequent article

A roadmap for simulation

For over 50 years the JKMRC has applied a unique education-based research strategy to develop modelling and simulation tools that are "fit for purpose" for industrial application. These tools are widely used for the analysis and optimisation of mining and mineral processing systems. As the mining industry context evolves to deal with declining head grades, falling commodity prices, professional skill shortages, and an exponential growth in the volume of data, a re-evaluation of what "fit for purpose" means in the future is required. It is contended that future industry needs for simulation-based decision support requires tools and systems that incorporate: • Multi-component modelling, • Models of complex sensor behaviour, • Integration across the physical value-chain e.g. resource to market, • Financial analysis including risk and uncertainty assessment, • Enabling multi-criterion decision making (technical, financial and environmental), • Ore-body knowledge at multiple scales, • The use of fundamental numerical models to provide insight for the development of practically useful models, and • Decision support delivered through remote operations centres. JKMRC and CRC-ORE are collaborating to develop a next-generation simulation-based decision support system that assists in addressing these challenges. The Integrated Extraction Simulator (IES) combines many years of pragmatic and successful work integrated with modern technology trends - in particular the rapid move to cloud-based computing