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By J. A. Luckmann

"SynopsisThe purpose of this paper is to introduce an innovative approach to risk management in surface mining operations, namely, positive risk. Traditionally, risk management focused on mitigating losses (negative). Positive risk, on the contrary, reverses the approach and focuses on exploiting a project’s inherent benefits (positive).The inability to accurately determine project objectives during the project planning phase and the failure to achieve those objectives during the execution phase is a major problem for any project management in the mining environment.The advance of computer aided design models for mine planning enables mining engineers to examine various options within a very short time. Employing positive risk management combined with drivers-based risk management when evaluating these options provides an ideal opportunity to investigate areas for improving the mining project’s profits. Furthermore, harnessing positive risk returns during the planning phase contributes immensely to the successful achievement of project objectives.Mining has inherent business risks, which can appear overwhelming when considering the risks associated with a mining project schedule, cost, and safety or resources, etc. The question is – how to manage risks in a surface mining environment, and what process methodologies, work methods, processes, and standards should be used when considering the surface mining risks. Applying the principles of positive risk management to manage surface mining risks is not only relevant, but definitely beneficial to mining projects and to the mining industry as a whole.It would be beneficial for risk managers and risk professionals to understand the roles of positive risk ‘drivers’, also known as ‘propitious attractors’. Identifying, analysing, estimating, and understanding the propitious attractors, their behaviour and their influence on project risk events helps considerably during the planning and execution phases. The theoretical and practical knowledge of both sides of the risk – the downside risk (negative risk) and upside risk (positive risk) – can add substantial value to any organization when downside risk is adequately mitigated and upside risk is beneficially exploited."

Jan 1, 2015

This paper is a collection of thoughts and frameworks. It addresses a simple question: æIf we are to believe the large number of people and institutions indicating that humans are destroying the Earth and that the end is nigh, why do we bother trying to be sustainable?Æ The paper lays out evidence for the existence of multiple hazards to global society. The existence of a hazard alone is insufficient to make an assessment of risk. Risk estimates are required to support decision-making. An approach to assessing risk is provided and some limited data are presented. A new ædefinitionÆ or statement of what sustainability (in a broad sense) might have become is then given. A decision framework for guiding decision- making about the risks is developed. This framework includes a definition of leadership with inherent implications for what determines whether a leadership position by title is actually leading. The paper concludes by offering a view of minerals industry sustainability and considerations around maturity in the current economic situation. It is hoped that by placing this collection of frameworks around sustainability, a supporting structure emerges that will facilitate action. It is proposed that action taken in this way will be more effective than reaction to regulation or even social license to operate imperatives because it is driven by a more holistic view of the challenges and the potential roles of individuals û all of whom are potential leaders at some scale of action.

Jan 1, 2009

By George S. Dulikravich

An advanced semi-stochastic algorithm for constrained multi-objective optimization has been adapted and combined with experimental testing and verification to determine optimum concentrations of aJ10ying elements in heat-resistant and corrosion-resistant H-Series austenitic stainless steel alloys. The objective was to simultaneously maximize a number of alloy's mechanical properties. This research will result in a rigorous tool for the design of high-strength H-Series steels and other types of alloys unattainable by any means existing at the present time. Such a material-by-design tool will also be able to reduce or minimize the need for the addition of expensive elements such as Cr, Ni, Co, Nb, Ti, V, etc. and still obtain the optimum properties of an aJ1oy.

Jan 1, 2003

By D Cliff

Despite advances in technology, the Australian underground coal mining industry continues to have incidents involving spontaneous combustion. Managing these incidents relies heavily on understanding the state of the event as it develops and controls are applied. Gas analysis plays a major role in aiding this interpretation. This interpretation is based upon laboratory testing of coal samples under conditions very different to those found in an underground coal mine. This paper will explore the links between laboratory data and actual events. It will highlight the difficulties of using laboratory data. It will outline the relevance of laboratory data and how it can be usefully applied to manage spontaneous combustion events as well as in establishing relevant trigger action response plans to facilitate early detection and control of such events. The paper will identify some of the factors that need to be applied when adapting laboratory data to apply to the underground coal mine. It will outline the need for comprehensive knowledge of the local conditions and gas concentrations to be expected at all locations in an underground coal mine. Further, it will demonstrate the need for mine environment monitoring to go beyond simply measuring gas concentrations but also to include reliable atmospheric pressure, temperature and air velocity monitoring.CITATION:Cliff, D, 2013. Gas analysis - Linking the laboratory with reality, in Proceedings The Australian Mine Ventilation Conference , pp 277-282 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 1, 2013

By E Beltran, S Ngunz, F Orrante, F van Zyl, M Westcott

"The primary control objective of the project is to achieve milling optimisation by ensuring that the energy available for rock breakage is used as efficiently as possible. This is achieved by increasing the level of mill filing until a process constraint is reached. Stable operation against this limiting constraint is then maintained to ensure long-term optimised operation.Semi-autogenous grinding (SAG) mill control optimisation presents a number of challenges. SAG mills have multiple inputs that are used to control multiple outputs (MIMO process). Secondly, the SAG mill loading process is a ‘high inertia’ process that can be approximated as an integrating process. This means that it is open-loop unstable. The hybrid control strategy presented implements an advanced ‘load stabiliser’, which transforms this integrator process into a more manageable first order process, which can be steered stably against the constraints. This SGS hybrid Expert control strategy implemented on both SAG mills at the Porgera concentrator therefore consists of two integrated parts responsible for:stabilising the mill load to a targetdriving the mill load target to the maximum determined by the process constraints (eg maximum power draw) to maximise efficiency and throughput. A comparative study is done between the operation of the plant for a period of a month before and a month after the implementation of this strategy. The results indicated a significant improvement in the SAG mills’ stability and operation as well as a reduction of overload situations leading to a loss of throughput.Citation:Ngunz, S, van Zyl, F, Orrante, F, Beltran, E, Westcott, M and Wilson, S, 2016. Simplified Hybrid Semi-autogenous Grinding Mill Control - Explanation and Practical Results at the Porgera Concentrator, in Proceedings 13th AusIMM Mill Operators’ Conference 2016, pp 313–320 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Oct 10, 2016

By Cripps-Clark CJ

Sulphur partition between metal and slag has been examined on a cast-by-cast basis for BTIP furnaces. Partition values. were calculated from thermodynamic equilibrium data together with oxygen activities computed from the manganese partition. The S-C interaction coefficient, esc , was treated as an adjust- able parameter and the agreement between calculated and measured S partition values optimized. In the case of furnaces operating with low viscosity slags this procedure led to estimates of esc in close agreement with previously measured values. The same analysis applied to daily average data for several Kawasaki Steel furnaces led to the same esti- mates of e c s , indicating a similar approach to equilibrium. Silicon partition between metal and slag has been examined on a time average basis and found to be far removed from thermodynamic equilibrium for most Australian furnaces. A study of Japanese furnaces of comparable size reveals a temperature dependence of Si parti- tion which appears to be close to equilibrium. Australian furnaces approach this behaviour only when operating with low viscosity slags. A preliminary examination of the effects of burdening with TiO 2 on the silicon partition is also reported.

Jan 1, 1980

By X. Gumede

A model is being developed to quantify the benefits for mining houses resulting from the reduction in greenhouse gas and energy consumption by the application of innovative blast designs in addition to direct financial benefits throughout the mine to mill value chain. The conversion from shock tube initiation systems to electronics and some changes to powder factor measured on an open pit mine had previously been used to show significant improvement on blast outputs. Benefits were realised on drilling, blasting, loading, hauling and beneficiation. Quantification of the relationship between powder factor and reduced greenhouse gasses is investigated in this study. The study has highlighted new data that must be recorded and hence some assumptions were made as to fuel consumption and the energy in crushing was obtained from the Bond work equation. The mine to mill projects in an open pit platinum mine and a quarry produced energy savings and reduced greenhouse gas emissions associated with the careful application of explosives and blast innovations. The less fines project showed an increased carbon footprint. The model provides a new insight into how project feasibility should be decided based on economic and environmental viability.

Jan 1, 2012

By Bekta? Uz

In this research, geological characteristics of sand quarries around the village, Kemerburgaz Akpinar, are studied and the mineralogical, petrographical, chemical and technological characteristics (such as sieve analysis, relative density, water absorbtion etc.) of the sand samples, obtained from the area are explained. In the general area sand' quarries, being in lacustrine formations belonging to Neogen, the stratigraphic location of the sand occurences take place at high levels of these formations, geologically. All of this pattern, being under 1 mm with a ,particle dimension, it ranges from 0,5 mm in the quantity of 99 % to 0,25 mm in the quantity of 15 relative density is 2,65 g/cm3 ; water absorbtion is 0,9%. Mineralogically, the sand samples contain Quartz (84%), Feldspar (3%), Calcite + Aragonite (10%), Pyroxen+Amphibole (1-2%), Garnet+Tourmaline (0.5%), Olivine (0.1-0.5%). Besides, sand samples contain SiO2 with the quantity of above 90%. Containing Quartz at high levels for mineralogical, petrographical and chemical characteristics, Akpinar sand will be evaluated as silica sand when the carbonate mineral is removed with the method of ore preparation such as leaching.

Jan 1, 2005

By J. B. Nanor, J. Lorengo, M. Misra, C. B. Bucknam

The dissolution of mercury during the gold cyanidation process is the cause of many environmental, health and processing problems. The removal of mercury-cyanide complexes from synthetic solutions and process water were investigated using sodium and potassium dimethyl dithiocarhamates and sodium sulfide as precipitating reagents. The results have shown that efficient mercury removal can he achieved by the formation of stable mercury compounds with the addition of potassium dimethyl dithioearhamate. The mercury dimethyl dithioearhamate precipitates are stable under plant operating conditions, and they do not have any deleterious effect on gold adsorption by activated carbon. Furthermore, it is possible to stabilize mercury in the heap during cyanidation by adding dimethyl dithioearhomate.

Jan 1, 1999

By S. Chander, A. Briceno

The effect of sample storage in argon and in air on the kinetics of oxidation of pyrite from a coal source was studied using accelerated-weathering tests that were performed in laboratory columns. Prior to the weathering tests, the samples were crushed, ground and stored for various periods of time in either argon or air. The test results showed a dramatic difference in the rate of oxidation of the aged samples. The interpretation of the differences was based on the hypothesis that the aging of pyrite led to the formation of surface coatings that changed with time. "Dry" oxidation produced surface coatings that had properties different from those produced by "wet" oxidation. The significance of these results to pyrite/reagent interactions during flotation and in evaluating the acid-mine-drainage potential of pyritic waste materials is discussed.

Jan 1, 1995

By M. M. Salari Rad

An investigation of gold distribution in the mill products of Sar Cheshmeh beneficiation plant demonstrates that on average 44% of the gold is routinely recovered as a by-product in the copper concentrate, and the remaining is lost to the tailing. In order to evaluate the causes of gold losses, the distribution and mode of gold occurrence in the Sar Cheshmeh ore and mill products were studied. Searching for gold within samples and within individual grains of sulphide minerals was carried out by SEM in the backscattered electron mode and SIMS, respectively. The mineralogical distribution of gold revealed by microbeam techniques were combined with the results of relevant metallurgical experiments including, sizing, heavy liquid separation, and diagnostic leaching tests, and the nature and location of gold in the ore and mill products were determined. The combined results of the experimental approaches pursued suggest that while there are some gold in solid solution and/or -colloidal size within sulphides of the Sar Cheshmeh ores, "visible" gold is the principal form of gold occurrence at Sar Cheshmeh.

Jan 1, 1999

By Huntington Adams

The arrangement of a flow of cyanide-pulp through Pachuca tanks in agitation, so as to permit a continuous process, instead of alternate filling, agitation, and emptying, has been proposed by various writers within the last two years, and more particularly by A. T. Grothe, agent for the Brown patents on Pachuca tanks in Mexico. It was first put into practice, I believe, by M. H. Kuryla at the Esperanza mine in El Oro, Mexico. The starting of agitation in Pachuca tanks after filling may offer no serious difficulties with ores which do not settle rapidly in such tall tanks; and the adaptation of the tanks to continuous agitation under such conditions may give simply a somewhat more convenient method of treatment and greater agitation-capacity for a given number of tanks, because of the saving of time lost in filling and discharging. But in the treatment of pulp which tends to settle rapidly, as in the cyaniding of concentrates or of the whole pulp of ores containing heavy sulphides, the packing of the slime at the bottom may cause much trouble. The use of the radial air-pipe attachments near the top of the cone and of the air-valve outside of the air-lift tube at the bottom may obviate the difficulty to some extent; but the action of the radial air-pipes on the cone-sides is that of a sand-blast, and their continuous use cuts through the tanks. Moreover, even when these pipes are used, some pulps will pack tightly below them in the cones. Under such conditions the use of Pachuca tanks with intermittent filling and discharging becomes a troublesome process. Time is lost in starting agitation; large quantities of compressed air are wasted; pulp is blown over the tank-tops; and not infrequently it may be necessary to dig out the bottoms of tanks by hand. This trouble is the only important one occurring in the use of Pachuca tanks; and, since it is caused by intermittent filling, the arrangement of a continuous flow of pulp from tank to tank,

Jan 1, 1912

By S. Weiss, E. Espinoza

The El Sauzal gold-silver deposit is a high-sulfidation, epithermal precious-metals deposit hosted by an east-dipping sequence of dacitic and rhyolitic pyroclastic and debris-flow units of probable Oligocene age. Total gold production since startup in late 2004 is approximately 450,000 oz. of gold. Above the sulfide boundary gold is mainly disseminated as small grains interstitial to alunite, kaolinite and quartz. The majority of the ore is found in quartz-alunite-kaolinite altered rock that mantles tabular to irregular silicic cores of vuggy, residual quartz ±kaolinite ±dickite. Grade domains are modelled as subhorizontal to east and southeast-dipping. Higher-grade domains cut across alteration zones and also coincide with transitions from vuggy quartz to quartz-alunite-kaolinite. The highest grades are commonly found marginal to vuggy quartz in transitional, hematite-rich quartz-kaolinite and quartz-alunite-kaolinite rock.

Jan 1, 2007

By L. du Preez, J. D. Steenkamp

This paper introduces the concept of clean steel production from a pyrometallurgist’s perspective to the broader metallurgical community. A simplistic overview of the steelmaking process from iron ore to car body manufacturing is followed by an introduction to the South African steel industry and the technologies that it utilizes. The process is illustrated by an overview of the flow sheet and technologies for the production of clean steel at Saldanha Steel, South Africa.

Jan 1, 2015

By N. P. Reddy

This paper describes an experimental setup for multiple-fan ventilation systems at the ventilation laboratory of the WVU Department of Mining Engineering. Housed in a 30 ft by 70 ft room, the experimental setup consists of three 18 in. variable-speed axial-flow fans, the 18 in. diameter fiberglass tubing and fittings for arranging networks, and the pitot tube measuring and data acquisition system. The fiberglass tubing and fans can be organized into the non-planner network of two fans or three-fans. It is mainly designed for studying the characteristic curves, operating points, and fan stall for the multiple-fan ventilation system.

Jan 1, 1992

By Jifan X, Yongyu W, Liangjing L

Shallow interception of groundwater is a special dewa- tering form in the specific geological and hydrogeological conditions. It has an economic and technical effect. The roof of the Fankou Lead-zinc deposit is the Hutianqun aquifer made up of the limestone of the upper Carboniferous system. - A "water-bearing basin" is surrounded by the aquifuge and the aquitard below ¦0 m level at the Shiling Hill section in the Hutianqun aquifer. Based on the natural conditions, an interception gallery is excavated at -40 m level out of "the water- bearing basin", the other gallery excavated at ¦0 m level in the poor water-bearing zone of the Jinxing Hill. During 20 years of experience, the better interception effects have been gained.

Jan 1, 1988

By Wenying Liu, Marek Pawlik

Long-chain ionic surfactants, with fatty acids and amines as the most important representatives, are widely used as collectors in froth flotation. These surfactants, generally referred to as weak electrolyte collectors, frequently form solid insoluble precipitates within a certain pH range. However, the action and behavior of these colloidal precipitates in froth flotation systems are not well understood and has not been well decoupled from those of dissolved forms. The objective of this study was to understand and compare the role of colloidal precipitates with that of the dissolved forms at gas-liquid and gas-liquid-solid interfaces. Using primary amine as the model surfactant, experiments were carried out to measure: the maximum volume of bubbles generated in the presence of dissolved and precipitated forms of the surfactant; surface tension for both forms of the surfactant using the drop shape and maximum bubble pressure methods; and contact angle using the sessile drop method. The experimental results showed that: in the presence of the precipitate, bubble volume was smaller, which was correlated with the lower surface tension and higher contact angle measured; the surface tension of solutions containing surfactant precipitate was affected by the surface age of liquid droplets. This study enhances understanding of the interfacial behavior of long-chain ionic surfactants under different conditions, which would help improve the efficiency of reagent utilization in froth flotation.

Jan 1, 2014

By E. M. Frizzell

It is unlikely that improvement in truck efficiency and capacity can fully offset the effects of inflation, fuel cost/shortages, and increasing haul distances as in the past. Therefore, investigations of haulage systems less sensitive to these problems are warranted. Thus, this Bureau of Mines contract research study on alternative continuous haulage systems was prepared. This study identifies the physical, economic, and technological parameters in the application of continuous haulage systems with special attention to under pit slope conveyors and skip hoisting systems. The evaluation data were gathered from extensive literature searches, European/North American mine visits, and industry comments. The study concludes that continuous underground haulage is a viable method within the proper geometric configurations.

Jan 1, 1979

By B. C. Viljoen

"SynopsisCommencement of the next phase of the Lesotho Highlands Water Project is a year or so away from becoming reality. Some 50 km of tunnels in the form of access adits, shafts, diversion tunnels, and main waterways will be constructed. Sprayed concrete will form an integral part of the temporary and permanent rock support systems that will be installed. Furthermore, the use of sprayed concrete as a final tunnel lining solution was proposed as a viable alternative to concrete linings in the feasibility studies that preceded the forthcoming implementation phase.The aim of this paper is to make the reader aware of all the sprayed concrete related issues that engineers tend to grapple with during the design and construction of tunnel projects and other underground works. Primarily, these issues would include selection of applicable design parameters, technical specifications, construction application methods, quality control and, most importantly in the context of final or permanent linings, the durability of sprayed concrete.The International Tunnelling Association (ITA) Working Group (WG) 12 has been tasked specifically to publish a set of recommendations on the Quality and Control of the Application of Sprayed Concrete and the Testing of Sprayed Concrete for Durability. These tasks were also further explored at the recent World Tunnel Congress (WTC 2015) that was held in Dubrovnik, Croatia at the end of May 2015.IntroductionSprayed concrete is presented in a variety of shapes, designs, forms, application methods and accompanying terminologies including shotcrete, gunite, pneumatically applied concrete, and the like. The International Tunnelling Association (ITA) decided to standardize on a single terminology, namely ‘sprayed concrete’, in order to simplify specification, interpretation of guidelines, and codes of practice."

Jan 1, 2015

By Parviz Montazer, Robert King, William Ubbes, Gideon Chitombo

This paper describes the results of a detailed study that was undertaken to define the spatial distribution of permeability within a five meter thick envelope around the CSM/ONWI room. Detailed fracture orientations and distribution were determined through mapping of the walls of the opening, logging of oriented core, and visual examination of borehole walls with a borescope and a T.V. camera. Over 3,500 measurements were made from which the three dimensional distribution of fractures was determined. Two principally different testing equipment designs and various methods of air injection tests were used in all boreholes to identify and characterize conductive fractures. Through analizing the distribution of permeability and fracture index around the room a zone of blast damage of approximately .5 m thickness was delineated. The effect of stress modification seems to extend farther into the host rock to approximately 3.5 m depth.

Jan 1, 1982