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By T. Tomioka

1. An Overall View of the Japanese Ferroalloys Industry 1) Depressed Demand for Ferroalloys: In Japan consumption of ferroalloys in the last ten years has decreased, although there has been some fluctuation from year to year. During this term production figures of the steel industry, which are closely related to consumption of ferroalloys, are as follows: Shipment of steel products for the domestic market has declined gradually from 69 million tons in 1979, which was the peak year for steel production, to 60.3 million tons in 1982 and 60.4 million tons in 1983, the level of 1978. In addition, exports also have been a downward trend since 1976, which was the peak year with tonnage of 34 million tons, to 28 million tons in 1982 and 31 million tons in 1983.

Jan 1, 1984

By D. Imeson, T. Grammatikopoulos, M. Aghamirian, M. Oliazadeh

"More than 70% of potash is produced worldwide by froth flotation. Flotation of potash was developed in the early 1930s. Amines are widely used for flotation of sylvite (KCl) from halite (NaCl) and insoluble materials such as clays. Amine collector is also absorbed by clays. Therefore, clays are usually separated by scrubbing and de-sliming prior to flotation. Alternatively, slimes can be floated ahead of potash flotation. Flotation recoveries of sylvite are commonly in the range of 85%, while losses can occur in slimes, flotation tailings and make-up of process brine. Ores containing free coarse-grained sylvite are generally screened, whereas both fine and coarse fractions are conditioned and floated separately. The unique features of potash flotation include solubility of sylvite in water, the size of particles floated and fast kinetics. Particles up to 2.3 mm can be floated and about 50% of flotation feed can be removed in the rougher stage in few minutes. The main challenges in potash flotation are the recovery of potash from slimes, flotation efficiency in the presence of carnallite and recovery of coarse potash grains. A review of potash flotation shows that there is still room for improvement in both coarse and fine potash flotation. The present paper reviews the most significant flotation parameters including reagent type and dosage, flotation circuits, flotation equipment size and new developments in potash flotation. The latter include new reagents, flotation technologies (Hydrofloat, Jameson and column cells) larger flotation cells and slimes flotation.INTRODUCTION Potash is the common industrial term for potassium in various chemical combinations and minerals soluble in water. About 90% of potash produced worldwide is used as agricultural fertilizers. Flotation is the main treatment process of sylvinite (KCl-NaCl) ores for recovery of sylvite (KCl). Potash concentrate should contain a minimum of 95% KCl and be relatively free from 0.2 mm KCl fines. The flotation process for beneficiation of potash ores was developed in United States and Russia concurrently in the early 1930s. In 1934, Potash Corporation of America applied flotation process in a commercial scale (Tippin R.B. and Huiatt J.L). In the initial application, halite (NaCl) was selectively floated by employing lead chloride as an activator and soap as collector. The sylvite concentrate was reported in the cell underflow."

Jan 1, 2012

By J. P. Thomson

Magnesium alloys are steadily improving their market share as structural components especially in the transportation sector. Therefore, there is a great deal of interest from the automotive and the metal casting industry to develop viable economic casting processes for magnesium-base alloys. This paper summarizes the preliminary results on the continuing projects within CANMET-MTL on casting processes such as gravity and low-pressure casting in sand molds, permanent molds and lost foam.

Jan 1, 2004

By Neill B. K, Fander H. W, Wong K, Dunlop G, O&apos

Commercial interest in refractory gold is increasing rapidly. This trend is supported by the work patterns of Amdel, where, apartfrom routine process- ing of free-milling and refractory ores, the majority of testing now includes biological and pressure oxidation studies to enhance gold recoveries. Central Mineralogical Services have examined, among other ores, an apparently unique type of refractory coating. A summary is given of experience at Optimet Laboratories, Pty., Limited. Research into nitric acid pre-oxidation, underway at the South Australian Institute of Technology since 1987, has shown significant improvements in gold recoveries, and in some cases, large reductions in reagent consump- tions. Three final-year student research projects were undertaken in 1990, jointly between the University of Adelaide and the S.A. Institute of Tech- nology. These projects involved biological pre-oxidation, pressure leaching, and Scanning Electron Microscope examination of refractory ores, and the resultant pre-oxidation and cyanidation products.

Jan 1, 1991

By Zhonglin Ye, Yifeng Shi

"This paper has outlined forms of Au & Ag losses in copper smelting process and methods for increasing Au & Ag recovery, analyzed factors influencing Au & Ag recovery in copper converting process, presented Au & Ag behavior in copper electrorefining process, and reviewed effect of current density/electrolyte circulation rate during electrolysis and surface finish of cathode on Au & Ag losses. Measures and research direction for decreasing Au & Ag losses in electrolysis have also been introduced. Based on Au & Ag behavior in copper electrorefining process and previous studies by others, new approach for increasing Au & Ag recovery in copper smelter has been discussed. And brief comparison has made between continued multiplication method and equilibrium method application in the case of calculation of Au & Ag recovery in copper smelter.IntroductionAs gold and silver are the major by-products from copper smelting process, efficient Au & Ag recovery has become one of the key approaches for copper producers to increase economic efficiency. With similar physicochemical properties, Cu, Au and Ag belong to the first subgroup of elements in the same periodic table. Au and Ag will be enriched into Cu phase firstly when both matte-slag phase and copper-matte phase appear in copper smelting process. However, great changes have taken place in Au & Ag proportions into individual phase due to changes of physicochemical conditions in each smelting process. Metallurgists at home and abroad have carried out a great deal of pilot plant tests and laboratory tests in order to increase Au & Ag the former Soviet Union with regard to Au & Ag losses in copper smelting process in the 1970s and 1980s, and he proposed solutions to increase Au & Ag recovery in copper metallurgical plants. As more than 20 years passed, Jingchun Lu's paper, Discussion on Increasing Au & Ag Recovery in Copper Smelting System, remains as a literature of the most comprehensive study. Based on Jingchun Lu's literature, the authors of this paper discussed new approaches to increase Au & Ag recovery in copper metallurgical plants with combination of many researches done by other researchers for over 20 years."

Jan 1, 2013

By D. D. Rodier

Most zinc concentrates contain some silver and varying amounts of such valuable trace elements as gold, indium, germanium and gallium. With increasing similarities in plant installations, the predominance of electrolyte process and the increasing environmental constraints on iron disposal, it is essential that zinc smelters optimize the recovery of any valuable elements in their feed stocks. The process options, to date, of smelting, flotation or leaching of silver-rich leach residues cannot be applied economically to all installations. It is therefore necessary that new innovative processes, to recover silver and other valuable metals from relatively low grade feeds, be developed. This paper attempts to place this strategy in the context of today's constraints and will also provide a simple evaluation tool for any process alternatives.

Jan 1, 1990

By R. T. Jones

The largest known platinum group metal (PGM) deposit in the world is the Bushveld Complex in South Africa, with the Great Dyke in Zimbabwe also being one of the biggest. It is therefore not surprising that the majority (just over 5 million troy ounces or 156 metric tons per annum) of the world's platinum is produced in Southern Africa. Primary smelting of ore concentrates is carried out in that region by five companies, namely Anglo Platinum, Impala Platinum, Lonmin Platinum, Northam Platinum, all of South Africa, and Makwiro Platinum in Zimbabwe. The only other primary smelter of platinum group metals is Stillwater Mining of Montana, USA, although very significant quantities of PGMs are produced as co-products by Norilsk Nickel of Russia. Smaller (but still significant) quantities of PGMs are produced by Falconbridge and Inco of Canada, also as co-products from nickel sulphide smelting. There are many similarities between PGM smelting and nickel sulphide smelting, and the range of technologies in use includes six-in-line rectangular electric furnaces, three-electrode circular AC furnaces, Peirce-Smith converters, and Anglo's ACP (based on Ausmelt technology). PGMs are also recovered from residue materials using DC arc furnace technology.

Jan 1, 2005

By Linda L. Chasko, Ronald S. Conti, John D. Cool

Mine operators often rely on mine rescue teams to save lives during an underground emergency such as an underground fire, explosion, roof fall or water innundation. It is extremely important that team members are provided with adequate exploration equipment and that training simulations are conducted in a realistic manner. A series of mine rescue training exercises was developed, conducted, and evaluated by the National Institute for Occupational Safety and Health (NIOSH) in cooperation with the Pennsylvania Department of Environmental Protection, Bureau of Deep Mine Safety and several mining companies. The exercises were conducted at NIOSH’s Lake Lynn Laboratory and operating mines during 1995 to 1999 and resulted in improved technology and training for mine rescue teams. For example, existing technologies were identified to help rescue teams during exploration. These included various chemical light shapes and laser pointers to identify team members and mark crosscuts and mine materials, strobe lights for mapping out escapeways and marking crosscuts, and thermal imaging systems to see through smoke. A hands-free communication system showed potential for enhanced communications between team members and the fresh air base. Anew team lifeline that allows for flexibility of movement between team members was developed. A positive-pressure inflatable escape device (IED) was used to isolate the “hazardous” environment from fresh air and allow rescue team members to traverse through. An inflatable feed-tube partition that can rapidly block large openings such as underground passageways and simultaneously provide a feed-tube for high-expansion foam generators was also deployed for several simulations. During the simulations, mine rescue team members donned self-contained breathing apparatuses (SCBA) and traversed more than 400-m of mine passageways filled with nontoxic smoke. Visibility ranged from 0.3 to 0.9-m. In one area of the mine, a kerosene heater was used to simulate a fire and reduce the oxygen concentration. In another area, a 1.5 pct methane zone was established. The team members searched for "victims,” administered first aid, mapped the passageways, built temporary stoppings, and ventilated the smoke-filled entries. Advanced training included the extinguishment of a conveyor belt fire in a surface fire gallery. Two teams, each carrying charged waterlines, were escorted into the fire gallery through both doors. These teams controlled the rollback smoke and extinguished 7 to 9-m of burning conveyor belt. Team members indicated that the exercises were extremely beneficial due to the realism of thetraining simulations.

By Denis Rickman, Jon Windham, Stephen Akers, Byron Armstrong

The soil crater formed by detonation of an explosive charge is of considerable military interest because of the common use of explosives to create soil obstacles. The soil crater is also an important piece of forensic evidence for the investigation of terrorist bombings. With recent advances in numerical codes, modeling and simulation of explosively-formed soil craters is becoming an attractive means of analyzing this phenomenon. Consequently, the need exists to better understand the relationship between soil properties and the resultant soil crater. An extensive database has been developed for the case of explosives detonated in or above in-situ soils of various types. However, in most cases, the soil properties were either not adequately quantified or the soil materials themselves varied such that the gross properties were poorly understood. A research program is underway to improve methods of relating soil crater dimensions to soil identification properties such as USCS classification, particle-size distributions, and Atterberg limits, as well as to soil composition properties such as density, moisture content, and volumes of solids, water, and air. As part of this effort, both explosive detonations conducted over well-controlled and well-documented soil backfills and companion numerical simulations were studied. This paper presents an overview of the effort.

Jan 1, 2010

By I. Duckworth

P.T. Freeport Indonesia operates a mining complex located in the highlands of Papua, Indonesia. This district consists of both underground and surface operations. The East Ertsberg Skarn System (EESS) is one of the major orebodies in this district. Subsurface caving of the EESS has been carried out in a systematic series of mining lifts dating back almost 30 years. Present production is from the third lift (Deep Ore Zone), which is scheduled to peak at 80,000 mtpd during 2009, with this rate sustained through 2015. The orebody is proven below the existing caving level, with the next vertical block called the Deep Mill Level Zone (DMLZ). This paper presents an overview of the DMLZ Mine based on recent feasibility level study. The mine is being designed for a peak production rate of 29.2 million mtpy, with 1,803 total ore draw points spread over a panel caving footprint of about 1.3km by 375m. The present reserves for this mine total 501 million tonnes. Located 1,400-1,800m below the original surface, the DMLZ will be one of the deepest caving operations in the world. Production is scheduled to commence in 2015. Discussion is provided on most design aspects including; caving methodology and layouts, geotechnical predictions and risks, ore handling systems, ventilation design and associated infrastructure, high-lift pumping system, cost estimation and expenditure scheduling.

Jan 1, 2010

By III Feeley

Coal is the nation's most abundant fossil energy resource and serves as the primary fuel for the U.S. electric-power industry. However, its continued and expanded use is often challenged by the nature and amount of its associated impurities, such as mineral matter, sulfur, and trace elements. The moderate- to high-sulfur content of many U.S. coals is of particular concern today as potentially more stringent regulations requiring further reductions in sulfur dioxide emissions are being considered. The most prevalent method currently employed to control SO2 emissions from coal-burning facilities is post-combustion flue-gas desulfurization. However, physical coal cleaning (a.k.a. beneficiation, preparation) methods can also be effective in removing sulfur and ash impurities from coal prior to combustion. In a typical physical cleaning operation, raw coal is crushed to about 50-mm (2-inch) topsize, and then screened into coarse, intermediate, and fine size fractions. Crushing liberates some of the ash-forming minerals, including the portion of inorganic sulfur (pyritic) not chemically bound to the coal matrix. The percentage of impurities liberated generally increases as the coal particle size is reduced. Coarse- and intermediate-sized coal particles are typically subjected to specific gravity-based cleaning methods, while fine-sized (less than 0.5-mm) coal particles are beneficiated using froth flotation, a technique based on surface property differences. Greater cleaning potential exists at finer sizes because of increased liberation of impurities, but this potential is not fully realized because of inefficiencies associated with fine particle separation using state-of-the-art coal cleaning technologies.

Jan 1, 1990

By K. Spence

"The notion of “value” has always been a subjective and contentious issue. Indeed, value is in the eye of the beholder. There are as varied methods and practices for valuing property, as there are industries in which they are applied. For example, there is replacement value, insurance value, salvage value, appraised value, book value, and fair market value, to name a few, although in the mining industry, valuations usually refer to fair market value.In the Canadian mining industry, at present, there are no comprehensive regulations or guidelines that specify which approaches or methods are appropriate for use in the valuation of mineral projects. In January 1999, The Mining Standards Task Force of the Toronto Stock Exchange and the Ontario Securities Commission recommended that the Canadian Institute of Mining, Metallurgy and Petroleum (CIM) establish a committee to review and advise on approaches and methodologies for the valuation of mineral properties. Among the approaches to be considered are included the following: the discounted cash flow approach, the cost approach, the option pricing approach and the market comparables approach. In addition, methodologies differ depending on whether the project is at the exploration stage or the producing stage.The CIM Special Committee on the Valuation of Mineral Properties (CIMVal) expects that its final report will form the basis for a Canadian code or standard for the valuation of mineral properties."

Jan 1, 2002

By Viggo C. Bertelsen, David G. Hammond

LOCATION AND EXTENT OF BART TUNNELS The San Francisco Bay Area Rapid Transit District (BART) during the past six years has become the Owner of 23.5 miles of single-bore tunnels. The tunneling experience gained while working closely with our Engineer and Contractors in the design and construction of these major transit facilities provides a basis for our "Owners" viewpoint. The 23.5 miles of tunnels are divided into two categories. Fifteen and one-half (15-1/2) miles of tunnels were constructed in soft ground underlaying the downtown areas of San Francisco, Oakland and Berkeley. Eight (8) miles of tunnels were built in "hard ground" in the hills separating Oakland and Berkeley from Contra Costa County and in the San Francisco hills on the Mission Line. Location of tunnels within the BART system are shown on Figure 1. The tunnels comprise 15.7% of BART's 75-mile dual track system. Their 176 million dollar costs (excluding rail, electrification or ventilation features) are 12.4% of the system's total estimated cost of $1.4 billion. The tunnels constructed in soft ground were shield and boring machine driven with ground support provided by steel liner rings. The exterior diameter is 17 foot, 6 inches in the majority of tunnels; however, on two tunnels with a 500 foot radius of curvature, the diameter was 18 feet. BART awarded 14 contracts for soft ground tunneling. The work was accomplished under free air or compressed air depending upon the ground water and soil conditions, safety requirements, and considerations for protecting adjoining property from damage either from the de-watering operations or settlements due to excavation. The tunnel bores, except on curves, were normally parallel being spaced at 32 foot centers on the Mission

Jan 1, 1997

By Hui Zhang

The leaching behavior of palladium powder in aqueous solutions containing NaCI or N'H4Cl was investigated. Cupric ion was used as an oxidant for the dissolution reaction. The effect of a number of leaching parameters such as temperature, concentration, stirring speed and surface area on the leaching rate was studied. The leaching system containing chloride and cupric ion was found to be very effective for the dissolution of metallic palladium. Based on the experimental results the overall leaching rate was believed to be controlled by a chemical reaction step. The dissolution rate of palladium was found to be first order with respect to the concentration of cupric ion and second order with respect to the concentration of chloride.

Jan 1, 1996

By M Fishwick Tapia

This paper was prepared and translated from the final report of the investigation into the Codelco Chile Salvador DivisionÆs air blast which occurred in the Inca-West area. In this section of the block cave mine, a stable arch formed covering an area of approximately 15 000 m2 . This zone subsequently collapsed producing a massive air blast. The collapse followed a series of planned extraction activities and occurred on 5 December 1999. This paper discusses the cave back arching event and the measures that were taken in order to induce the controlled collapse. This was to minimise risk to personnel, equipment and installations. The results obtained to date are presented.

Jan 1, 2000

By Fred D. Fox

INTRODUCTION Approximately two years have elapsed since the first summary of the Grizzly Gulch Tailings Disposal Project was presented (1). Since that time, various physical modifications and additions to the existing treatment system have transpired. Further, Homestake and the entire mining industry have been impacted severely by additional modifications and additions concerning regulatory reform aimed at total disciplinary permitting and hazardous waste management. The following paper summarizes the past accomplishments relating to the Grizzly Gulch Tailings Disposal Project, correlating these accomplishments with future plans that are being developed to comply with regulations and to continue Homestake's commitment to environmental protection. The famous Homestake Gold Mine, located in Lead, South Dakota, has been operating in the Black Hills region for over a century, approximately 12 years before the south half of Dakota Territory was admitted to the Union as the State of South Dakota (2). During the 104 years of operational development, Homestake's Gold Mine, as well as the entire mining industry, have been influenced by numerous governmental regulations dating back to the Refuse Act of 1899 which regulated the deposit of debris from mines and stamp works. The enactment of the National Environmental Policy Act of 1969 may be thought of as the beginning of a long line of unplanned steps to deal with the many concerns of matters pertaining to the environment. Environmental awareness continued into the 1970’s, in which the Clean Air Act, Federal Water Pollution Control Act, Safe Drinking Water Act, Toxic Substances Control Act, and the Resource Conservation and Recovery Act (RCRA), to name a few, surfaced.

Jan 1, 1983

By Elmer Palmer

As part of the Goldcorp Inc growth plan Minera Peñasquito SA de CV has developed its polymetallic deposit with a large ?state of the art? concentrator to process lead and zinc ores. The plant consists of two grinding lines including 38ft diameter SAG mills and 24ft diameter ball mills. During mid to late 2009 concentrator commissioning activities commenced. First concentrates were produced in October 2009 and now the plant is meeting its design basis of 65,000 mtpd per line. This paper describes the design and operational experience to date for its grinding circuit design, together with the recently commissioned HPGR crushing circuit.

Jan 1, 2012

By R. A. Jankowski

Although the number of operating longwall mining systems has remained relatively consistent over the past five years, longwall production levels have increased significantly during this period. Longwall production currently accounts for approximately 50% of U.S. underground coal production. While longwalls are highly productive and offer other advantages, operations employing this method of mining continue to experience dust compliance problems. This increased longwall productivity has meant that far more dust is being produced. An improved understanding of the longwall face ventilation system and advancement of face ventilation technologies are necessary to ensure all face personnel are allowed to work in an environment that is free of excessive levels of airborne respirable coal mine dust. The Dust and Toxic Substances Control Branch of the National Institute for Occupational Safety and Health's Pittsburgh Research Laboratory has examined several basic principles of the longwall face ventilation system, and has evaluated the effectiveness of numerous improved face ventilation techniques for longwall mining systems. These include identifying improved techniques for measuring face ventilation parameters on longwall mining sections and investigating the fundamental relationship between face air flow and the entrainment and dilution of respirable coal mine dust. Studies have been completed to determine the impact on face dust levels from using belt entry air to ventilate the longwall. Novel methods have been identified to increase the amount of face air flow and to manage face air flow to most effectively minimize face workers' dust exposure. Unique systems of auxiliary face ventilation have been developed and evaluated at full-scale, simulated longwall test facilities. The theoretical and applied aspects of each of these principles and technologies are discussed. Application of these results, throughout the longwall mining industry, as documented from surveys conducted in the early 1980's and 1990's, have reduced the health hazard associated with excessive exposure to respirable coal mine dust.

Jan 1, 1998

By J. Yue

"Mount Milligan mine is located in northern British Columbia. The concentrator employs conventional SABC grinding circuit with bulk sulphide flotation processes. Commissioning started in September of 2013 and nameplate production of 60,000 TPD was reached in the fourth quarter of 2015. As is typical with many mill ramp ups, bottlenecks developed as throughput increased. Since then, plant modifications and new control philosophies in the comminution and flotation circuits have been implemented and evaluated. The mine-to-mill collaboration played a key role in reaching target throughput rates by improving blast fragmentation and implementing temporary pre-crushing. Results of the projects as well as ongoing challenges/bottlenecks and solutions will be discussed.IntroductionMount Milligan Mine is a copper-gold producer located approximately 253 km northwest of Prince George in British Columbia. Production commenced in September 2013 and reached nameplate capacity of 60,000 TPD in December 2015. Average head grades for the mine life average 0.18% Cu and 0.39 g/t Au.Circuit DesignOriginal process design began with run-of-mine ore from the pit crushed through a 60-110 gyratory crusher, conveyed to a live ore stockpile and fed to the mill via four variable apron feeders. The concentrator circuit employs SAG mill - Ball mill - Pebble Crusher (SABC) grinding configuration to grind the ore down to a target P80 of ~200µm. It is then fed to two parallel trains of flotation tanks, each consisting of five 200 m3 tank cells with the first two being roughers and last three being scavengers. Concentrate streams from roughers and scavengers are separately reground with a closed circuit Tower mill and two open circuit ISA mills operating in parallel, respectively.Three stages of cleaners upgrade roughers/scavenger products to 25% Cu followed by a cleaner scavenger stage. The final concentrate is then thickened and filtered to approximately 9% moisture and shipped off site (Figure 1)."

Jan 1, 2017

By Gus Van Weert

Capital and operating costs for a 10 tpd NITROX PROCESS® demonstration plant are being established. The flowsheet is based on Dickenson Mines' Red Lake arsenopyrite concentrate. Support for the work comes from a number of mining companies, engineering firms and the Northern Development fund of the Ontario Government.

Jan 1, 1998