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By Singh T, Singh D. P

India has limited resources of coking coal. Most of the coking coal seams are located in Jharia Coalfield. These seams were worked in the past by the bord and pillar system in a haphazard manner, which has resulted in honeycombs of old working. Most of such areas are under fire. In order to meet the demand of coking coal in the 21st century, it is essential that the coal locked due to old underground workings is recovered fully by conducting opencast mining to an ultimate depth of 500 m. The major problem envisaged in conducting opencast mining in such areas will be the stability of pit slopes over voids and the behaviour of subsided material in the pit slopes. An attempt has been made to simulate this complex situation from a specific section of the rockmass of a mine in an equivalent material (EM) model. The old workings existing in upper coal seam (V) were simulated by developing staggered bord and pillar workings in two sections and depillaring them. Opencast mining was conducted for recovery of coal locked due to irregular working in coal seam V. The slope instability caused by intersection of the slope with the void, during frontal working (by shovel-dumper combination) was observed in various situations. In this paper, the technique adopted for simulation of a 125 m thick section of rockmass in an EM model is outlined. Adverse effects of staggered workings and

Jan 1, 1988

There are two mechanisms in the flo- tation process by which particles are transported from the pulp to the con- centrate: bubble-mineral aggregation and entrainment. It is the chemical processes which occur in the pulp which are critical to the success of flotation since they control the floatability of different min- erals and the selectivity which can be obtained. However, these chemical pro- cesses are so complex that metallurgists are still limited in their ability to predict the floatability of particles in industrial circuits by consideration of the minerals present and the chemical environment. The alternative approach to understand- ing flotation is to examine the behaviour of minerals in industrial flotation pro- cesses, to recognise similarities and differences, and to define the "laws" which appear to apply. Using this ap- proach it has been found that minerals float at a rate which is proportional to their concentration in the pulp, and that the rate of flotation of different min- erals is influenced by variables which' affect the pulp or the froth phase. The ultimate application of this approach is the use of models for circuit simulation purposes. It is this alternative approach which is the theme of this paper. One of the most important problems in understanding the technology of flotation has been in defining the characteristics of the particles being floated. Particles entering flotation vary widely in size and mineral composition, and different par- ticle types float at different rates. These rates do not change uniformly as operating variables change. It has been conventional practice to assess flotation performance in terms of the metal contents of total streams because no better method has been available, and this procedure has obscured important effects which occur in

Jan 1, 1984

By Kuruppu M

Geotechnical design plays a key role in mine design. A proper geotechnical design provides a safe working environment and facilitates efficient mining operation. There are mainly three design approaches: (i) judgmental, based on observational and experiential facts, (ii) empirical, based on empirical design formulae; and (iii) analytical, incorporating numerical analysis. Most design applications are based on the design methods one and two as mentioned earlier. However, complexities arise in deep underground mining operations and deep open pit mines. These complexities and difficult geological environment introduce more uncertainties and simple empirical formulae would not be adequate as a design tool. These situations require numerical modelling and analysis of the design problems including interpretation of the results obtained from the analysis. There are several tools available for performing the numerical modelling and analysis. A brief review of the available tools is provided. The authors selected ANSYS (a general purpose finite element analysis tool) for use in mining geomechanics and geotechnical design. This paper includes several examples demonstrating the applicability of this software in designing mining structures. The authors hope that the design examples will demonstrate the use of the numerical modelling and analysis applications in excavation design.

Jan 1, 1995

The basic purpose of blast design is to produce rock in a size range which is within the requirements of the materials handling system. Once this is achieved, one would like to find the fragmentation which minimises total production costs. The former objective requires that fragmentation be assessed by some means, possibly as simple as counting the number of oversize rocks. To determine the 'optimum' fragmentation, however, accurate knowledge of the complete fragmentation distribution is required. The use of muckpile surface images to determine blast fragmentation is the only feasible technique when one does not want to disturb the production cycle; however, a number of problems exist with the use of images amongst which are determining size from a two-dimensional particle shape, estimating the fines which are missing due to image resolution, the size of a 'representative' sample, errors due to the distortion of particle images, etc This paper briefly describes methods of determining rock size from images and expands on the various errors which exist in assessing fragmentation by photographs. Methods to minimise and account for the errors are given, when possible.

Jan 1, 1976

By Toomey P. T

In many open cut coal mines, rivers and large creeks can cause planning and operating difficulties, both in the terms of the more obvious location of the current watercourse, but, and sometimes more importantly, past meandering of the watercourse. Prevent and past flow regimes may have deposited large alluvial sequences within the current mining areas. The presence of groundwater within the alluvium further complicates the planning and operating practices.A situation exists at Saraji Mine in which alluvial sediments overlie a massive sandstone sequence which in turn lies at about one metre above the coal seam. The problems encountered include high levels of groundwater ingress to the pit, highwall instability, and an unacceptably high rate of blast hole collapse (prior to charging with explosives). Other aspects of the dragline stripping operation were also affected.

Jan 1, 1992

By Richmond GD

The Hellyer concentrator of Aberfoyle Limited commenced production in 1989 processing a fine grained, massive sulphide ore containing Zn, Pb, Ag, Cu and Au as values. Four concentrates are produced - copper/silver, lead, zinc and bulk (Pb/Zn) - with overall payable recoveries (1991) of 80 per cent Zn, 55 per cent Pb, 50 per cent Ag, 30 per cent Cu and ten per cent Au. Metallurgical development work commenced immediately after plant commissioning, and continues. The flotation response and liberation analysis on a size basis highlighted reagent balance problems associated with tower mill regrinding of sphalerite, poor conditioning of flotation pulps, poor selectivity for fine galena, and insufficient liberation. These were the main causes of values lost to tailings, values reporting to the 'wrong' concentrates and of impurities in the concentrates. Modifications to tower mill regrind circuit operation, and the use of improved conditioning techniques have greatly improved concentrator performance, particularly in the finer (-5 micron) size fractions. Studies of concentrator and laboratory flotation by size and liberation analysis are the basis of diagnostic metallurgy. The techniques used to evaluate the improved concentrator performance are discussed.

Jan 1, 1993

Conventionally, a combined system consist- ing of a dry or wet pulverizer and kneading mac- hine is applied to the pretreatment of fine mat- erials for agglomeration, especially for pellet- izing. However, treatment cannot be expected to be satisfactory owing to the complexities of the process. A new process was developed to over- come the defects inherent in the conventional process. This new process treats certain fine materials having a moisture content somewhat lower than that suitable for pelletizing in a ball or rod mill. The mill is of special de- sign in which grinding and strong kneading are performed to give an extremely homogeneous ball- ing material with appropriate size distribution and pelletizing characteristics. The most serious problem in this process is the choking of sticky materials in the mill. A specially designed rubber lining was installed in the mill to overcome this trouble. This paper presents actual results from our iron ore pelletizing plant relating to the pelletization of other fine materials.

Jan 1, 1974

Since the mid-1970s there has been increasing attention in the South Pacific area to the problems of disaster planning and management at various levels, mainly from regional through national to provincial levels. This concern has been expressed in a variety of ways. International aid donors have made their views known in commentaries or reports. Seminar discussions have been organised at the regional level (such as at Suva, 1976; Suva, 1979; Tonga, 1982 and Suva, 1983). In-country training workshops or meetings have been organised (such as the "Disaster Preparedness Workshops for Non-governmental Organisations" in Pacific countries, jointly run by the Australian Red Cross and the Australian Overseas Disaster Response Organisation and supported by AIDAB, in Vanuatu, 1985; Solomon Islands, 1985; Western Samoa, 1986; Fiji, 1987; Tonga, 1987; Lae and Port Moresby, Papua New Guinea, 1988) or held outside the area (ACDC at Macedon, 1981). Training and/or research institutions have been established such as the East-West Center, Honolulu, and the Asian Disaster Preparedness Center, Bangkok (more Asia oriented). As part of the East-West Center Pacific Islands Development Program's Disaster Preparedness Project, a detailed manual of disaster preparedness and response procedures and guidelines has been published (Carter, 1984).Table 1 and figure 1 show that the area with which this discussion deals is a highly fragmented island region, comprising many small, some minute, nations, both in land area and population. The social structure is predominantly rural, with the capital city often making up a small part of the total population and, in absolute terms, little more than a small town. Outside the administrative and governmental activities concentrated in the capitals, in most cases the indigenous inhabitants depend on subsistence agriculture or on usually a monocultural concentration on a cash crop, most frequently coconuts.

Jan 1, 1990

By Ibrahim AR

The experimental phosphate mine of abu Tartur has been recently placed into production. Some problems'have been encountered in maintai- ning grade control due to the differences between early block estimates and actual produ- ction grade. An area of 100 km2 is evaluated by using four methods of evaluation , namely polygonal, inverse distance , inverse distance squared and geostatistical methods. The results of calculations are compared statistically with the control values of grade and thickness. The comparison showed that the. kriging technique gave better estimations for the relative ore reserved, while for grades or thickness any of these techniques except the polygonal can be Used.

Jan 1, 1986

By Vanderberg B

A 3D, PC based computer program is currently under development by Blasting Analysis International, Inc., to analyze the kinetics of full scale blasts with two or more high-speed motion picture cameras. Todays common approach of utilizing only a single camera system can, in some cases, lead to great errors and erroneous conclusions when motion is assumed to be in a predefined plane of motion. CMe phrase, "What you see is what you get, it no longer true in 3D."). This is especially true in blasting environments which exhibit complex and/or predominant structural geology. The 3D system eliminates this problem, and includes automatic corrections for vertical and horizontal camera optic axis orientation, dimensional controls, lens distortion, field set-ups, projection imaging and digitized inputs. The only information required is the surveyed or known coordinates of at least six non coplanar points in the field of view. Motitn from each camera view is then digitized, transformed through a direct linear transformation, and processed with the 3D software, which also automatically time matches the data, even when the high-speed cameras are operated at different speeds. Eleven calibration constants are generated using an overdetermined system of linear equations to output the true 3D coordinates of motion in the time domain. Applications for this 3D approach are not restricted to just analyzing the kinetics of a blast. The system is sufficiently flexible to allow an accurate, quick and economical method of bench face profile analysis, generate muck pile profiles and estimate volumetric calculations. The recording systems for these applications can be common 35mm still photography and/or video equipment. It is envisioned that this system will soon replace expensive laser surveying systems at a fraction of the cost in the near future. It is also an excellent system to accurately quantify drill pattern layouts and the spatial locations of each blasthole. This information is required for generating single hole based synthetic seismograms to accurately predict the vibrational outputs of full scale blasts. In terms of litigation concerning claims resulting from blast induced ground vibrations to structures, the system is proving to be an excellent and economical method of performing pre-blast surveys where differential settlement is suspect.

Jan 1, 1990

Over the past 15 years, Artificial Intelligence (AI) techniques have shown promise of providing the ability to capture `human intelligence' into a computer program. The sub-fields of Expert Systems and Artificial Neural Networks are finding increased use in industry to perform tasks previously considered the domain of human thinking. But, are these methods just a new type of software much like that of the past or is real magic hidden within the lines of code? Will this field continue to enjoy high growth rates and if so, what developments will we see in the near future? Which algorithms and methodologies will continue to grow? This paper discusses a number of paradigms which can be used to create successful applications. There are certain barriers; some psychological - some linked with knowledge acquisition, that must be overcome or avoided to ensure system performance. Development time also requires careful consideration before embarking on an Al project. The paper focusses on constructing goal-driven systems that transfer high-technology solutions from the research laboratory to the plant floor. Respect for system users is of paramount importance - whether their involvement is to access contained information or to participate in program maintenance as new knowledge becomes available. Examples of successful and unsuccessful AI implementation in Canadian industry and academia provide evidence of the importance of this issue. The paper also examines some current constraints on applying AI in the real-world. Among these problems are automated knowledge acquisition, methods to acquire data during run-time, real-time systems (hardware versus software), explanation and justification features and adaptive/leaning systems.

Jan 1, 1995

China has abundant bauxite resources, but these resources are mostly of a diaspore, which has a feature of low Al2O3 to SiO2 mass ratio, typically ranging from four to six. Compared to other materials, this kind of raw materials consumes more alkaline and energy in the process of metallurgy, and incurred a high alumina production cost. To solve this problem, researchers in China have done a lot of work on removing of the silicon from bauxite. Under the impetus of these works, in 2003, the first flotation plant of diasporic bauxite in the world was constructed in Zhongzhou, Henan, China. Seven years of operating experience shows that this technology can signifi cantly reduce the costs of following-metallurgy processing. These efforts are an important reference for the processing of similar resource. In general, for Western scholars it is diffi cult to fully understand these works because most of them are published in Chinese. In this paper, a detail introduction for the research progress on China bauxite de-silica flotation was presented, these works involved crystal chemistry, wettability of bauxite minerals, collector and modifi er in bauxite fl otation and flotation practice, etc.

Sep 13, 2010

By Steinbrucker G

Improvements in mining by the application of electronics necessitates analy-sis of the objectives and problems. A detailed analysis has shown that increased tunel-ling performance is one of the most important objectives. In mining, the environmental conditions for machines, their handling and servicing are very hard. Therefore a health monitoring system for tunnelling machines in hazardous areas has been developed. This system measures operational parameters, such as-flow, pressure, temperature, etc., de-rives forecasts of possible failures from these values, and assists maintenance person-nel. Important data are transmitted to a surface computer via telephone cables. Health monitoring is based on the cognition that slow deterioration of characteristic parame-ters, e.g. fluid loss, are symptoms of wear. Sudden changes of machine parameters indi-cate sudden destruction. Computer technology is very advanced, but transducer technolo-gy has not,been able to keep pace. Filling the yawning gap in the mining industry is a challenge to technology and requires special techniques. Machine monitoring and automa-tion in underground mining is still in its infancy. A lqt of development and research work is still necessary. The risks are great-The expected benefit due to increased min-ing performance (up to 5 %) justifies the risks in development.

Jan 1, 1985

The Koongarra uranium deposit was discovered in August 1970 by Noranda Australia Limited. Denison Mines Limited acquired the rights of ownership in October 1980 and has continued the 'struggle' to bring the proposed mine, containing approximately 13 300 tonnes of U308 of Indicated ore and having a value of $1 billion (1984 dollars), into operation. During the 14 years that have passed, the owners have found it necessary to deal with numerous Federal, State and Territory government departments, aboriginal representatives, handle thousands of communications, attend and convene countless meetings and spend millions of dollars. This paper addresses the history, the requirements, the problems and the costs to date for what - no return.

Jan 1, 1984

By S Hughes

The smelting of concentrates and secondary materials has been subject to increasing challenges in recent years due to declining grades of feed materials, increasing impurity levels and ever more stringent environmental regulations. In addition there has been a growing focus on maximising the efficiency of energy usage and recovery of values. New opportunities have been created with rising metals prices and improved systems for the collection of secondary materials, giving rise to a need for more flexible process solutions.This paper focuses on a number of specific cases where a process solution has been developed using the Outotec« Ausmelt Process to meet particular feed material challenges and overcome limitations inherent when employing traditional pyrometallurgical processes.The first case involves the development and commercial implementation of a smelting process to recover values from zinc smelting residues typically deposited into dams as a waste product. The second case describes the application of the Ausmelt process for the smelting and converting of secondary copper feed materials, including e-waste. These materials contain a wide range of metals and plastics and need to be processed appropriately to maximise the recovery of values whilst avoiding environmental problems. The third case study covers the smelting of nickel concentrates containing elevated magnesia levels as well as nickel bearing catalysts with high alumina content, neither of which can be readily processed when employing traditional pyrometallurgical technologies. CITATION:Hughes, S, 2013. Pyrometallurgical process solutions for complex raw materials, in Proceedings MetPlant 2013 , pp 519-530 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 15, 2013

By Lu S, Jiang Y

The conventional transportation system in open pit, a to u.* itc:,~> truck., to carry the ore along the ramps. Normally, the transportation distance increases greatly as mining progresses deeper. A new approach to overcome the above disadvantage is to adopt a buried roadway by which ores is transported by conveyors from the mining area to the outside dump in the shortest distance so that the production efficiency is greatly increased. Maintenance of the buried roadway in a good working condition is the key factor that determines the success or failure of the proposed approach. This includes the determination of support load, types and structures of support and other related supporting measures. The crucial problem here is to effectively control the load applied on the buried roadway in a certain range that the ordinary support can stand. Based on the theoretical analysis, numerical modelling and physical simulation testing using equivalent material, this paper studies effects on control of the support load by adopting certain measures, for instance reinforcing the surrounding rock and placing the extendable layer between the support and a rock mass. Furthermore, the influence of the dynamic load induced by the movement of heavy vehicles on the stability of the buried roadway is also investigated.

Jan 1, 1995

Minerals similar to the indicator minerals used in kimberlite exploration are widespread in the Cainozoic alkali basalts of north Queensland. Magnesian ilmenite, pyrope garnet, chrome diopside, chrome spinel, phlogopite and zircon were recovered from most of the localities examined. The occurrence of these minerals creates significant problems when indicator minerals are used for diamond exploration. Basaltic ilmenite is visually similar to kimberlitic ilmenite. Untransported grains are rounded and have pitted surfaces. Basaltic ilmenite grains often have exsolution lamellae and reaction rims of titanomagnetite. Although kimberlitic and basaltic ilmenite are chemically similar, basaltic ilmenite grains are usually less magnesian than their kimberlitic counterparts. Basaltic ilmenite contains very little Cr203. Pyrope garnet occurs as megacrysts and in a variety of xenolith lithologies in north Queensland basalts. Most basaltic garnet is Cr-poor and comparable with kimberlitic garnet from Groups 3 and 5 of Dawson and Stephens (1975). Wine-purple, chrome-bearing garnet is common in kimberlite but rare in basalt.

Jan 1, 1984

By G MacSporran, I Sheppard

The practical application of LaneÆs theory on optimum cut-off grade policy has to date proved difficult for selective stoping in large-scale underground mining. The key to determining an optimum cut-off grade is the ability to rapidly perform complex mine layout designs combined with rapid output of multiple potential schedules. This paper describes aspects of the detailed investigation into estimating a practical static cut-off grade for the two main orebodies in Mount Isa MineÆs Enterprise Mine. Rule based automated scheduling software was used to evaluate thirteen different stoping layouts (including design infrastructure and capital development) of the Enterprise MineÆs two main orebodies, with over 200 schedules generated. The investigation illustrates the application of commercially available software to solve the problems of generating multiple cut-off grade stope designs and achieving the otherwise insurmountable task of rapidly generating and valuing multiple scenarios for each stoping layout. Each scenario was evaluated using modelled net cash flows of the mining, concentrating and smelting operations of the company and calculating NPV. The cut-off grade for each orebody was selected based on the cut-off grade that achieved maximum NPV û with an appropriate production rate. Underground mine scheduling is a complex task involving the adherence to a number of simple scheduling rules and the balancing of several competing drivers. The study also found that: while each scheduling rule itself is simple, the compounding complexities of their interaction preclude manual scheduling from being a realistic option. there is a maximum sustainable rate of production possible for any given stoping layout, and that the actual maximum production rate is also a function of the required number of years of sustainable production. the optimal cut-off grade was different for each orebody û a recognition of the impact of the different characteristics of each orebody.

Jan 1, 2003

By B OÆNeil

The Trent-Severn Waterway is a 386 km long navigation route through central Ontario between Lake Ontario and Georgian Bay, and is operated by the Parks Canada Agency. Its primary focus is to pass recreational boats through a system of 44 locks. The Big Chute Marine Railway (BCMR) is one site in the system that provides transportation for boats. The BCMR carriage is used to transport boats and their passengers on the inclined railway a distance of 230 m over a natural barrier from one body of water to another, with an elevation difference of 18 m. The unique feature of the haulage system used in this application is the variable angle of the incline from about 20 per cent rise changing to horizontal and followed by 20 per cent decline. In such conditions, unlike as in standard incline haulage, special configuration of hoists and drives is required. On the uphill part of the track, there is a need to have a motoring mode, on the downhill part a regenerating mode and on the horizontal part a combination of motoring and regeneration is required. The original system was built in 1978 and employed four 100 hp dc drive mine hoists to haul the 100 tonne conveyance loaded with 90 tonnes of boats. Due to failures and operational problems with the original system, in 1999 Parks Canada awarded a turnkey contract to ABB for a new, modern system of four single drum hoists. The new system was put into operation in 2000, only six months after receiving the order. The hoists are controlled by digital drives and a digital control system. Due to dramatic changes in the load conditions for individual hoists involved, the new system features many interesting solutions like changing drive modes from speed to torque control and a multiple, regulated braking system. It is a unique hoisting system, which could be also used in mining applications.

Jan 1, 2005

The task of designing stable high walls and spoil piles in strip coal mines, and stable openings with controlled roofs and floors in underground collieries - within the constraints normally imposed by economics - depends upon a reliable assessment of rock mass strengths and rock mass reactions under a variety of stress conditions. Of the geological factors influencing internal friction and cohesion within rock masses, many may be determined qualitatively or empirically from bore-hole evidence. Rock types, descriptions and properties of intact rocks, location of boundaries, limits and degrees of weathering, potential for slaking or decomposition of rocks when exposed, bedding characteristics, the nature of rock anisotropy and the likely effects of water on rock mass properties can be assessed from bore- hole data. Discontinuities, whether they be major such as faults and dykes, or minor such as joints and fractures, present a greater problem, and in most instances the mine geologist must resort to additional techniques to describe or predict their occurrence, nature, frequency, intensity or physical properties. Information on ground water and seam gas is available from bore-holes within certain levels of reliability.

Jan 1, 1977