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By S. Y. Chen

A new process comprising metallizing reduction, magnetic separation, and electroheat melting separation is proposed with the aim of achieving high recoveries of iron, vanadium, and titanium from vanadium titanomagnetite. The effects of magnetic intensity, reduction temperature, reduction time, carbon ratio, and coal particle size on the efficiency of reductionmagnetic separation were investigated, the reaction mechanisms elucidated by SEM and EDS analysis, and the optimal process parameters established. Recoveries of up to 80.08% for titanium, 95.07% for iron, and 71.60% for vanadium were achieved. The reduction sequence is shown to be: Fe2O3 ? Fe3O4 ? FeO ? Fe; Fe2TiO5 ? Fe2TiO4 + TiO2 ? Fe + FeTiO3 ? Fe + FeTi2O5 ? Fe + TiO2.

Jan 1, 2014

By Tim Hughes, Steve Gannon, Jennifer Abols

"In the past year, two very innovative gold ore processing plants have been designed, built and commissioned by Gekko Systems Pty Ltd. The first plant in Vietnam utilizes conventional crushing and ball milling followed by gravity concentration (Inline Pressure Jig (IPJ) and Falcon concentrator), flotation, intensive leaching (GFIL), the first industrial scale use of AuRIX®1001 ion exchange resin and a cyanide destruction circuit. The second plant, in Australia, uses a 3 stage crushing circuit to crush the gold ore to minus 1mm, followed by gravity concentration utilising a rougher, scavenger, cleaner circuit of IPJ’s and a Falcon concentrator. A direct smeltable gold concentrate is produced as well as a lower grade concentrate for future intensive leaching or sale. Both plants were designed and built within very tight time frames and budgetary constraints. The experience gained during the plants’ design, commissioning and operation are discussed.INTRODUCTIONGekko Systems (Gekko) is a leader in the development of innovative technology for gravity recovery and intensive cyanidation. It provides low cost and metallurgically optimal solutions for its customers. It has also led the trend away from whole ore cyanidation (CIP/CIL) towards gravity/intensive cyanidation (GIL) and gravity/flotation/intensive cyanidation (GFIL) plants. These types of plants offer low capital costs, low environmental impact and maximum return to investors (Rob J Longley et al, 2002). Key to this type of flowsheet is the application of a continuous concentrate unit, such as the InLine Pressure Jig (IPJ), which is designed to produce high gold gravity recoveries at a coarse grind (Sandy Gray, 2003). When combined with other gravity devices, and/or flotation, and intensive cyanidation, using the Gekko InLine Leach Reactor (ILR), very high overall recoveries can be achieved.In 2004, Gekko launched a new range of products called Gekko Modular Systems. The idea was to provide off the shelf, complete solutions for the separation and recovery of complex and free gold as well as the pre-concentration of diamonds. A series of modules were designed that incorporated Gekko manufactured as well as outsourced equipment. Gekko now offers modules ranging from feeding and conveying to crushing, gravity recovery, flotation, intensive cyanidation, refining and detox (see Figure 1)."

Jan 1, 2007

Conventional hand drawn isopach maps of the cover of the Bulli Seam are too eomplex for use in the delineation of large domains of similar cover. Isopach maps prepared from trend surfaces fitted to the cover data are much simpler in form and so provide a convenient method of delineating broad domains of similar cover.

Jan 1, 1968

By L. W. Berry

Drill and blast planning is critical to successful mine production, both in timing and in results. However, typical planning, reporting, and information exchange usually involves large quantities of data collated in a discordant set of spreadsheets, databases, and reports. Collecting, analyzing, modeling, and distributing all data necessary for efficient drill and blast operations is time consuming and cumbersome. MineSight Axis Drill and Blast provides an extensible core of functions, seamlessly integrated with other MineSight software tools, to make sense of this information. The benefits of improving the management of drilling and blasting processes are immense and result in improved fragmentation at a lower cost, improved shovel and truck productivity, and enhanced ore processing.

Jan 1, 2011

By Manuel Pérez-Tello, María M. Salazar-Campoy, Óscar Rodríguez-Hoyos

A common problem during the operation of the Kaldo furnace is the formation of accretions and blockage of the injection lance due to splashing. This typically occurs during the processing of anodic slimes for the production of doré. In this work, a 1:7 scale model of the Kaldo furnace currently in operation at Metalúrgica de Cobre, Mexico, was built in transparent acrylic plastic. Water and colored oil were used to represent the doré and slag, respectively. The model was used to determine the maximum penetration distance of the injection lance under a variety of experimental conditions at room temperature. Input variables included two types of oil, rotation speed, inclination angle, and the fraction of the vessel volume occupied by the liquids (φ). A mathematical correlation for the dimensionless maximum penetration distance of the injection lance d ∗ as a function of φ, the Froude number of the liquids in the vessel (Fr), the Reynolds number of the gas jet (Re), and the oil-to-water kinematic viscosity ratio (η)was developed. Reasonable agreement between the calculated and experimental values was obtained. Digital images showed that splashing was caused by the turbulent gas jet impinging upon the free surface of the liquids, whereas the cascade effect was negligible. The results of this work have been useful to improve the operation of an industrial Kaldo reactor.

By Manuel Pérez-Tello, María M. Salazar-Campoy, Óscar Rodríguez-Hoyos

A common problem during the operation of the Kaldo furnace is the formation of accretions and blockage of the injection lance due to splashing. This typically occurs during the processing of anodic slimes for the production of doré. In this work, a 1:7 scale model of the Kaldo furnace currently in operation at Metalúrgica de Cobre, Mexico, was built in transparent acrylic plastic. Water and colored oil were used to represent the doré and slag, respectively. The model was used to determine the maximum penetration distance of the injection lance under a variety of experimental conditions at room temperature. Input variables included two types of oil, rotation speed, inclination angle, and the fraction of the vessel volume occupied by the liquids (φ). A mathematical correlation for the dimensionless maximum penetration distance of the injection lance d ∗ as a function of φ, the Froude number of the liquids in the vessel (Fr), the Reynolds number of the gas jet (Re), and the oil-to-water kinematic viscosity ratio (η)was developed. Reasonable agreement between the calculated and experimental values was obtained. Digital images showed that splashing was caused by the turbulent gas jet impinging upon the free surface of the liquids, whereas the cascade effect was negligible. The results of this work have been useful to improve the operation of an industrial Kaldo reactor.

By Urie R. W

Fluidized bed roasting of copper concentrates from Mt. Morgan, Mt. Lyell, Mt. Isa, and Peko was performed in a 3 ft 6 in diameter, slurry fed, pilot plant roaster operated under autogenous conditions to produce calcines with desirable leaching properties. A 12 in. diameter, externally heated roaster, provided with a dry feed system, was also used.An account is given of important factors which influence roaster behaviour and performance, and the effects of operating variables on calcine composition and leaching properties are described. Due to copper ferrite formation, a maximum of approximately 50 per cent of the copper in the calcines may be in the form of CuO before the copper leach efficiency falls significantly below lOO' per cent. Recovery of gold by cyanidation of leach residues was consistently high and independent of roasting conditions.INTRODUCTIONIn traditional practice copper is produced by pyrometallurgical techniques when the ,copper minerals in the ore or concentrate are predominantly sulphides, and by hydrometallurgy when the minerals are oxidized. Copper smelting is most suited to large scale operations, and for many years small to medium size mines with sulphide orebodies have been interested ill; alternative processes.Since hydrometallurgical plants (ie. leaching and electrowinning plants) are essentially unitized, they may be scaled down in output without much loss in efficiency or increase in processing cost, and many proposals have been made for the application of this type of process following roasting of the sulphides to render the copper soluble. However, until the advent of fluidized roasting, it was not possible to control the roasting operations sufficiently precisely to produce calcines consistently of the required leaching characteristics.

Jan 1, 1961

By R. M. Kear

Strategic and tactical planning are both required in the mining industry but have completely different objectives and require different environments. If these are not fully understood, then the best value for a mining operation may not be realized. This paper examines the differences in these approaches and how they interface in the mining environment. The objectives, content, skills required and the implied management issues for these two components are examined with the hope that this will assist management and the planning teams in defining their respective roles and expectations. The opinions are those of the author based on his experience on several mining operations and projects.

Jan 1, 2006

By A. A. Debrah

Artisanal and small-scale mining (ASM) plays a fundamental role in the national and local economies of resource-rich countries in Africa. As such, more effort must be geared towards fostering this type of economic activity to sustain livelihoods in rural communities. Across Africa, efforts to operationalize ASM based on a sustainable development framework have been quite tedious and often ineffective. This is because most of these frameworks lacked context and an understanding of the continuum from the artisanal through small-scale and up to the junior miner, grouped under the general term ?ASM?. Driven by the need to contextualize some of the definitional issues in this niche sector, and gain a clearer understanding of their peculiar challenges, this paper aims to contribute to the debate on ASM by considering two of Africa?s resource-rich countries ? Ghana and South Africa. Since South Africa has made greater inroads in protecting the interests of small-scale miners, we thus draw comparisons from both countries? approach to ASM, outline the lessons learnt, and provide recommendations regarding the ways forward.

Jan 1, 2014

By Donald A. Bruce

"Abstract The Deep Mixing Methods (DMM), in their current forms, have been employed in the United States since 1986, although an earlier version had seen service from 1954. The earlier developments were strongly influenced by practices in the Nordic countries and Japan, while by the late 1980’s several DMM systems had been developed in the U.S. itself. Since then, DMM has continued its evolution, principally via the challenges of a series of large, landmark projects, but also via distinct, significant technological advances. This paper highlights the key points in the history of DMM in the U.S., and provides an overview of the different methods currently in use.In the BeginningIt is a common misconception that the history of applications of the Deep Mixing Methods (DMM) in the United States dates from 1986 when SMW Seiko Inc. — a subsidiary of Japan’s Seiko Kogyo Company — was established in the Bay Area. However, the author believes that Intrusion Prepakt Co.’s patented MIP (Mixed in Place) system had been used, albeit sporadically (about 30 projects are recorded), since 1954 (FHWA 2000, 2001). Ironically, by 1961 this single auger method had been extensively used under license in Japan for excavation support and groundwater control — by the Seiko Kogyo Company. By 1972, the original MIP technique had been succeeded by more advanced Japanese methods, involving multiple augers. Intrusion Prepakt have long since become defunct.The first systematic studies of contemporary Deep Mixing Methods in Japan began in 1967 when the Port and Harbor Research Institute of the Ministry of Transportation began laboratory testing using granular and powdered lime for treating soft marine soils. Fundamental studies continued through the early 1970’s, by which time the development of industrial scale equipment was well advanced, having its first application on a marine trial near Haneda Airport. Coincidentally, laboratory and field research also began in 1967 in Sweden (“Swedish Lime Column Method”) for treating soft clays using unslaked lime. Reportedly the progenitor was a Norwegian, Kjeld Paus, who had made observations on fluid lime columns in the U.S. It would seem that developments in Japan and the Nordic countries proceeded independently until 1975 when the technology leaders from each group (Broms and Boman; and Okumura and Terashi, respectively) presented their — very similar — findings at a conference in Bangalore, India. Limited technical exchanges ensued thereafter.Whereas the Nordic developments continued to focus on the use of dry reagents (cement and lime) and relatively light equipment compatible with operating on and in very soft clays and organics, the Japanese progressed into the use of fluid reagents (cement-based grouts) and heavier equipment for both marine and land-based projects. Thus, by 1986, there were a large number of proprietary (wet and dry) DMM systems in Japan, and a rapidly growing market already by then accounting for over 12,000,000 m3 of ground treatment."

Jan 1, 2014

By Michael Allen, Paul Worsey

In underground blasting, the pull of the initial cut is the limiting factor for the success of the rest of the round. By improving the pull of the first cut, a critical step is made towards improving the entire round. This project attempted to optimize a burn cut’s effective pull by varying the depths of the relief holes in the burn. The effect of varying the depths of the relief holes was investigated, including depths longer than that of the cut’s charged holes. The overall objective was to consistently achieve greater pull than in a standard burn, using an identical amount of explosives. Increased pull results in savings of both time and cost in underground heading advance.

Jan 1, 2015

By E. Milke, A. Arnold, B. Friedrich, A. Sydykov

CaF2is often used as a fluoride addition to the chloride salt flux in the melting of aluminium scrap. The solubility of CaF2in the chloride salt system is limited. Dissolved CaF2is considered to improve the properties of salt fluxes. Experimental investigations indicated that the solubility ofCaF2in 70 wt % NaCl/30 wt % KCl, German salt flux used in aluminium scrap melting, might be lower than expected according to literature data. The pseudo binary section CaF2-(70 wt % NaCl-30 wt % KCl) was investigated by differential thermal analysis (DTA). The determined solubility of CaF2appeared to be considerably lower than presented in the literature. The pseudo binary section calculated using thermodynamic data partially confirmed the results. DTA allowed us alsoto determine the crystallization temperature interval of the two phase eutectic consisting of the solid solution NaCl-KCl and CaF2. Keywords: aluminium recycling, phase system, salt flux, CaF2, NaCl, KCl, solubility

Jan 1, 2004

By John C. Machisak

The National Safety Competition is sponsored and conducted annually by the Bureau of Mines, U.S. Department of the Interior, to give greater impetus to the building of programs safeguarding the employees of the mineral industries from disabling work injuries. The results of the 1960 National Safety Competition are presented in this publication. Mines and quarries that were awarded the Sentinels of Safety trophy for the best safety record in their competitive group and those mineral operations that ranked second, third, fourth, and fifth in the competition are listed with a summary of their achievements in preventing disabling work injuries. In addition, this publication presents statistical data on disabling work-injury experience in all other mines and quarries participating in the annual competitions.

Jan 1, 1962

By Kevin G. Stricklin

Introduction Continuous monitoring techniques have been used in the US and abroad for many years. A continuous miner has a monitor that measures methane and automatically gives a warning if the methane exceeds 1%. It deenergizes the continuous mining machine automatically at a maximum concentration of 2%. Main fans are also continually monitored to ensure operation. Alarms may also be given at a remote location should a fan slow or stop. The systems being developed can continuously monitor various gases and equipment throughout the mine and transmit pertinent data to a surface monitoring station. At this station, conditions throughout the mine can be monitored and, in some instances, controlled. These are known as Mine Wide Monitoring Systems (MWMS). History The use of environmental monitoring systems began in 1976 when a federal court approved the petition of modification to use belt air at the face. The first mine to receive a modification did install a system to supplement existing safeguards. Later, the Mine Safety and Health Administration (MSHA) and the US Bureau of Mines (USBM) conducted tests dealing with the use of belt air. Findings from these tests are being used to set guidelines as requirements of a petition. These requirements include: • Velocity of air has to be 0.25 to 1.5 m/sec (50 to 300 fpm); • Monitors will be installed at each belt drive and tailpiece and at intervals not to exceed 610 m (2000 ft); and • An alarm level of 10 ppm, above the ambient level is appropriate. The early uses of environmental monitoring could only be used outby the last open crosscut. That may be a reason for an initial slow growth of these systems. In June 1982, MSHA began evaluating systems that could be used in returns to ensure that monitoring systems being used in areas where permissible equipment is required does not of itself pose an explosion hazard. This is known as the Mine Wide Monitoring Systems Evaluations and Sensor Classification program. The evaluations and classifications granted are based on electric currents and voltages. Use of mine wide monitoring systems The environmental aspect of MWMS in today's coal industry deals with carbon monoxide (CO), methane (CH4), and air velocity. Just as all mines are different and encounter different problems, the MWMS are diverse and can be used to provide necessary data in all areas of coal mines. Mine operators in an ultragassy seam, for example, may be concerned with monitoring methane, while a mine that used diesel equipment may want to continuously monitor for diesel contaminants. In a mine with roof fall problems, airflow monitors may be helpful as an indication of whether the air is flowing in its normal course and at its normal volume. Today's MWMS can monitor any or all of these parameters. Most systems can be expanded as mining needs require. For example, a mine is now being monitored for methane and five years from now CO monitoring would help increase safety. It may be possible to use the same system by adding additional equipment. In the US, 30 environmental monitoring systems were installed from May 1985 through May 1986. In 1984 and 1985, there were 38 and 44 environmental monitoring systems in operation, respectively. Due to mine closings, 11 of these are no longer in use. However, the number of mines using environmental monitoring systems increased to 63. Use of these systems are not limited to any geographic area or

Jan 9, 1987

By F. Essrich

A quantitative rockburst hazard assessment procedure was introduced on Elandsrand Gold Mine at the end of 1994. It is currently used to evaluate the seismicity-related risk in production areas on the mine. Six parameters related to seismicity, geology, mining layout, and production are rated and results are used as a planning tool on a regular basis. The applied assessment can be considered successful in that it promotes awareness of the seismic hazard and provides an opportunity to address seismicity-related mining problems. A comparison between high risk panels and those working areas with rockburst incidents showed that high hazard ratings reliably forecast the occurrence of larger events in the following month but they do not necessarily predict those working places with rockburst-related accidents. From this one may conclude that high levels of seismicity do not coincide with high rockburst rates.

Jan 1, 1997

By Steve Chorley

Open-type, or main beam, tunnel boring machines (TBMs) can achieve impressive rates of production. This type of TBM typically outperforms other types of TBMs currently in use around the world. In good ground conditions, main beam machines have achieved production rates of more than 1 km/month (0.6 miles/month). However, installing effective ground support in poorer rock conditions on main beam machines can be a major cause of concern. The design of main beam machines is such that installation of ground support equipment, particularly at the front of the machine in what is commonly known as the L1 support zone, has traditionally been limited to rock drills and basic working platforms. Personnel working in the L1 zone have, until recently, been protected by roof supports and extended fingers, often with restricted access to working areas.

Jan 1, 2011

Since its inception in 1962, the Julius Kruttschnitt Mineral Research Centre has adopted the view that an effective method of training highly qualified engineers for the mineral industry is the pursuit of postgraduate research programmes conducted in operations, that is, in the mines and processing plants of the industry which the research serves. The paper describes how this is achieved in practice, at little or no cost to the taxpayer, and explores the strengths and weaknesses of this approach in the context of a dual mission for the Centre: 1. The postgraduate training of engineers for the mineral industry. 2. The production of useful R &I) for the mineral industry. Topics discussed include financing, relationships with industry and Government, the maintenance of academic excellence, research style, the marketing of research, and limits to growth.

Jan 1, 1989

By Paul C. Schmall, John F. Donohoe, Arthur B. Corwin, Derek Maishman

Ground freezing was utilized to provide complete stability of the excavation face and complete groundwater cut-off for the jacking of the three tunnel boxes for the Interstate 90 / Interstate 93 approach to the Fort Point Channel crossing. Through a wide range of geological conditions and large buried obstructions, the freezing provided complete stability of the face so that a 11.5 m (38 ft) high free standing vertical face could be mined without the need for any additional face support. Obstructions were incorporated into the massive frozen ground matrix, and held in place so that they could be excavated with a minimum of disturbance. The freezing provided an absolute groundwater cut-off, and permitted the work to be done without disturbance to the active rail system immediately above. With the use of instrumentation such as borehole thermocouples, the effectiveness of the freezing was guaranteed and the jacking proceeded with complete confidence and assurance of the ground conditions ahead.

Jan 1, 2001

By John M. Gomes

The preparation of tungsten carbide by molten-salt electrolysis was investigated. Sodium tungstate in the electrolyte and carbon from the graphite anode were the source materials, Optimum results were obtained with an electrolyte consisting of 83 mole-percent sodium chloride and 5.7 mole-percent each of sodium tungstate, sodium metaborate, and sodium hydroxide; a temperature of 1,000° to 1,025° C; an anode current density of 37 amp/dm2 or less; and an initial cathode current density of 150 amp/dm2. The yield was approximately 0.45 g/amp hr. The electrolytic tungsten carbide product contained approximately 5.4 weight-percent combined carbon as compared to 6.1 weight-percent for pure tungsten carbide. Microhardness of the electrolytic tungsten carbide, determined with a 50-gram load, varied from 3,480 to 3,970 dph. The material was friable and could be ground in a laboratory ball mill to less than 400-mesh particle size.

Jan 1, 1969

By Tracy Brettmann

A new method for estimating ground vibrations caused by pile driving was developed as a result of a vibration monitoring program performed for a large pile driving project. The method is accurate, rational and theoretically based starting with energy actually transmitted to the pile (not the rated or operating hammer energy). This energy is then assumed to be transmitted to the soil in the form of surface waves that attenuate from both geometric and material damping. The main input parameters for this method include the energy transmitted to the pile and the dynamic properties of the soil (wave velocity, material damping, and unit weight). In this study we concurrently measured both: (1) pile driving of 14-in.-square, 65-ft-long precast concrete piles with a Pile Driving Analyzer?, and (2) vibration levels at various distances away from the piles during driving. A geotechnical study for the site was also performed that included measurement of the dynamic soil properties using both crosshole and seismic cone testing. This paper presents the data obtained from the study and compares the results to the values estimated using this new method. Vibrations from pile driving is a serious matter that impacts virtually every pile driving project. It is important that accurate methods for estimating ground vibrations be available to engineers and contractors.

Jan 1, 1999