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By Maurício Covcevich Bagatini, Maycon Athayde

Water consumption reduction in pellet feed operation is of paramount importance. Compared with traditional ball mills, high-pressure grinding rolls (HPGR) play an important role in Blaine surface area (BSA) generation to improve agglomeration properties, although stability is still a challenge. Grindability improvement of existing operation has a direct impact on the performance of the filtering and pelletizing operation. The results of this study, as a pregrinding operation, can be applied not only in new operations but also in existing ones, helping the operator control process variation in a more effective way while ore hardness increases. 

The General Purpose Simulation System (GPSS) is a computer simulation language that has been used for simulations of open pit haulage operations since the 60's. It is easy to learn, simple to use, and has a block-diagram structure that is amenable to load-haul systems. However, due to its lack of flexibility, there are situations where another language should be chosen. This paper reviews the characteristics and capabilities of both GPSS and FORTFAN with regard to open pit shovel and truck simulation. The relative advantages and disadvantages are highlighted and a case study presented along with comparative results from two computer models (one written in GPSS and the other written in FORTRAN).

Jan 1, 1986

By J. Hilgers

Metal prices are often predicted by relying on time trend projections of various economic indicators or even the trend in price itself Thus, time is the underlying explanatory variable acting through at best, a limited selection of economic variables. The price prediction method described in this paper differs from this by analyzing hundreds of economic variables to develop a few principle components that automatically capture the fundamental changes in the economy and delete duplicate or irrelevant information. This leaves a few principle variables to describe a state-space representation of the economy which can then be used for prediction. Forecasts of the price of a metal are then made based on these principle variables.

Jan 1, 1995

By S. A. Elmquist

Research activities performed by Cleveland-Cliffs Research and Hibbing Taconite plant personnel during the last decade have resulted in the development of an improved autogenous mill grinding circuit. Minus one (1) inch autogenous mill trommel oversize material, con-sidered to be a critical size, is magnetically cobbed and then crushed to 100% minus 3/8" prior to reentry into the feed end of the mill. Autogenous mill capacity increases, up to 25%, have been measured in pilot plant tests using this approach and are also anticipated for the Hibbing Taconite concentrator which presently has reached a 15.5% improvement.

Jan 1, 1994

By T. W. Flemal

Good afternoon gentlemen. To begin, may I say ?thank you? to the AIME for the invitation to be here today to talk about my company's experience with shovel, truck, pocket, to car loading. The other author of this paper is here today. (Introduce John Sweet). Before we get to the details of this paper I want to tell you a little about Erie Mining Company. Erie Mining Company is located on the east end of the Mesabi Range in northern Minnesota and is engaged in the business of processing taconite rock into iron ore pellets. In 1970, the twelfth year of production, Erie will produce its rated capacity of 10.3 million tons of high grade iron ore pellets. The plant is the first of five iron ore pelletizing operations managed by Pickands Mather & Co. with a combined annual production capacity of 21 million tons. This plant began producing high grade iron ore pellets in 1957 placing it among the earliest of taconite production facilities in North America. Historically Pickands Mather & Co. had been a leading natural ore mine managing firm in the Great Lakes region for more than 70 years. Pickands Mather & Co. moved into the new field of taconite mining and processing with management and operational experience from the open pits and underground mines. We were to learn much of volume taconite handling requiring new equipment and new procedures. A trial and error period through the early years of taconite processing developed through the operation of an experimental sized preliminary plant near the present Erie Mining Company site.

Jan 1, 1970

By James K. A. Harral

The growing national concern over energy has aroused a great deal of interest in the most efficient and least costly way to use our remaining fossil fuel reserves. A number of studies have been published which compare the overall thermal efficiency and cost of gas and electric energy. These studies have been carried out by a wide variety of organizations including Oak Ridge National Laboratory, The Rand Corporation, The Stanford Research Institute, and The Institute of Gas Technology. This paper is an attempt, by PGandE, a large combined gas and electric utility serving most of the northern and parts of central California, to compare the cost and efficiency of gas and electric energy for certain residential appliances using actual operating data and financial statistics for the year 1974, and thereby develop some guidelines for future energy developments utilizing these limited fossil resources. The appliances chosen for the study were kitchen ranges, clothes dryers, hot water and space heaters. These appliances were selected because they can be served with either gas or electricity and they account for approximately one-third of PGandE's total residential electric sales and nearly all of PGandE's residential gas sales.

Jan 1, 1976

By Nord L. Gale

Lead, zinc, copper, silver, cadmium and many other heavy metals which are potentially hazardous if released into the environment in wastewater discharges have been of considerable concern to governmental agencies, industry and the general public. In response to this concern, an interdisciplinary research team at the University of Missouri has been funded by the National Science Foundation-RANN program to study trace contaminants associated with the production of lead for the past eight years. Seven modern mines in close proximity to two lead smelters in the forested Ozarks of Southeast Missouri are the largest source of lead in the world and in 1976 alone produced 504,095 short tons of lead, 82% of the United States total production. This new and rapid industrial development in a sparsely populated. rural forest region has offered a unique opportunity for studying the impact of trace metals and for developing improved techniques to control detrimental effects. Research on the wastewater discharges and two methods of biological and recycle control are discussed in this paper. Although the two mine-mill complexes investigated in this study have many similarities, the differences between the two are substantive and warrant separate examination.

Jan 1, 1977

By R. Casagrande, L. R. Moore, J. Sessoms, P. Macy

"A South American nickel mine has been producing a nickel concentrate that also contains copper and iron (15 percent nickel, 5 percent copper, 28 percent iron) for the end use of stainless steel production. A critical specification for the quality of the steel is the iron to magnesium oxide ratio (Fe:MgO), with a ratio of below 3.5:1 having a substantial impact on the nickel value. This nickel concentrate producer historically mined the sulfur-rich mineral pyroxenite but had been forced to move to a magnesium oxide/silicate (MgO/SiO4)-rich mineral harzburgite, resulting in nickel recovery being reduced to around 50 percent to maintain the required Fe:MgO ratio. In this study, ore mineralogy, water chemistry and the chemistries associated with the flotation process were evaluated in an effort to increase nickel recovery while maintaining the Fe:MgO ratio according to specification. New chemistry was introduced with the specific goal of complexing with the MgO and retarding its interaction with the bubble flow in the flotation process.IntroductionGlobal nickel production in 2011 totalled to 1,770,000 tons, according to the Raw Materials Group (2013). From 1950 to 2005 there was an aggregate 4.4 percent increase in nickel production, with a market-value high of $1,000/ton nickel reached in 1998 (Mudd, 2010). Approximately 65 percent of nickel production is consumed by the stainless steel industry, with 12 percent of the remainder used in super alloys or nonferrous alloys. Nickel imparts corrosion resistance, temperature resistance and other benefits to its alloys (Table 1) (Oberg, 1996; Cáceres, 2003). The dominant types of nickel-bearing ores are classified as either laterites (limonite: nickel-iron oxide; and garnierite: nickel hydrosilicate) or magmatic sulfide deposits (pentlandite: iron-nickel sulfide) (U.S. Geological Survey, 2013a, 2013b). In 2012, about 40 percent of the nickel ore mined was sulfidic-type ores and about 60 percent was laterite. The processing of laterite ore is expected to continue to increase as the availability of sulfidic ores continues to decline."

Jan 1, 2015

The National Institute for Occupational Safety and Health (NIOSH) conducted field tests to evaluate the effectiveness of a wet head continuous mining machine for reducing dust exposure for continuous miner operators. Wet head technology delivers water via sprays to the continuous miner's cutter head as opposed to traditional standard sprays located on the boom and body of the mining machine. The sprays, positioned directly behind each bit on the cutter head, deliver water at the point of attack, serving to cool the bits during mining to reduce the potential for frictional ignitions. The sprays also flood the coal with water to potentially suppress dust generation. Dust surveys were conducted at several mines to evaluate the wet head's effectiveness to control respirable dust exposure at the continuous miner operator location and in the immediate return. Results show that the wet head miner improved air quality at both locations to varying degrees in some cases and not in others when compared to a continuous miner with a standard spray system.

Jan 1, 2010

By I. J. Wu

China’s land area, comparable in size to United States or Canada, contains diverse geological environments and mineral resource potential. The diversity in geological environments is such that the potential for developing many world-class mineral deposits in China is good. However, China’s mining sector was not open to foreign investment until the1990s. The long-term prospect for Chinese resource development is attractive because of China’s enormous population and cumulative demand for minerals. Approximately 33 foreign mineral companies, including 11 major internationals, are to various degrees active in China. Chinese mining laws and regulations pertaining to joint ventures with foreign companies are, from the international investment prospective, evolving slowly, but positively. This positive trend is continuing under the current government reform process, which is moving China towards a freer market economy. Although improving the enforcement of relevant laws and regulations is an ongoing process, the environment for mineral investment and joint ventures is increasingly more accommodating to foreign companies.

Jan 1, 2000

By J. B. Platt

Many utility fuel choices 1990-95 defied expectations, with utility decisions and coal market developments ever more closely linked. The Central Appalachian coal boom never occurred; clean-enough coal was developed in the hard-hit Midwest; Colorado-Utah coal surged; Pittsburgh seam production strengthened; utilities embraced Powder River Basin coal; and emission allowance prices collapsed. Competition drove productivity gains, but the future is not a simple repeat. Phase 2 brings fewer viable compliance options. Mega-railroad pricing has become a key risk factor --will this be countermanded by merging utilities and power market competition? Revenue losses from vintage contracts are problematic. Uncertainty also plagues natural gas, in spite of unanimity across major forecasts, since recent experience has been so heavily influenced by the gas bubble.

Jan 1, 1997

By David G. Chedgy

The Meadow River No. 1 Preparation Plant, owned by Sewell Coal Company, a subsidiary of the Pittston Company, was commissioned in the spring of 1974. The plant is designed to process 400 TPH of 5" x 0 raw coal. The 5" x 114'l fraction is processed in a Heavy Medium Vessel with the 114 x 28M reporting to Deister Tables for cleaning. The 28M x 0 fraction is cleaned in flotation cells, with the froth going to clean coal vacuum filters and the tailings to a static thickener where the underflow is reclaimed on Refuse Filters prior to disposal. The noise dosage a worker receives is determined by the ratio of the length of time the worker spends in a particular noise environment divided by the noise exposure in that particular environment. If the worker is exposed to several different sound levels, his total dosage would be the sum of each of the individual dosages. The equation for determining the dosage is: [ ]

Jan 1, 1976

By Susanne Pignolet-Brandom

Flash smelting products of a copper sulfide concentrate collected at successive levels in an experimental reactor have been studied by reflected light microscopy, scanning electron microscope - energy dispersive analysis and electron nicroprobe analysis. Chalcopyrite, intermediate solid solution, bornite, chalcocite, metallic copper, magnetite, iron-copper spinel, pyrrhotite, hematite, delafossite and cuprite have been identified in the product samples. The detailed reflected light microscopy study of these phases and their abundance in the samples has resulted in the identification of the series of reactions during flash smelting.

Jan 1, 1985

By W. Edwin Dill

For the mining industry, the Internal Revenue Code and regulations offer a range of choices in arriving at the allowable depletion. Each case is essentially unique. Two prerequisites can optimize these opportunities: communications between the mining company's tax specialists and its technical staff; and an understanding of IRS definitions. For the latter, a logical starting point is consideration of exploration and development, since they precede production and depletion is unallowable prior to production. Criteria for selecting engineering and accounting options for exploration and development indicate the necessity of interaction between these company functions to achieve the most favorable tax position.

Jan 1, 1982

By L. R. Gremillion

Chemical and mineralogical data on 25 apatitic phosphate ores of diverse origins from commercial deposits around the world were widely variable. From 14 to 18 chemical constituents of each sample were determined, and each sample contained 4 to 10 mineral phases. Altogether there were 34 different mineral phases, many of which occurred in only one sample. The samples contained varieties of francolites, fluorapatites, and mixed hydroxyl-fluorapatites. The apatite compositions calculated from the chemical data showed that certain types of substitutions were characteristic of different apatite varieties, but every variety had some degree of substitution of (CO3)2 for (PO4)3 and the P2O5 contents of the apatites ranged from 35.1% for a North Carolina apatite to 41.9% for a Missouri apatite. In a concentrate with a grade of 32% P2O5, the North Carolina sample should contain about 8.7% gangue and the Missouri sample about 23.7% gangue. To optimize the digestion process of a phosphate are, it is necessary to consider the dissolution behavior of the different mineral phases during acidulation and the effects they may have on the chemical properties of a fertilizer intermediate. In the production of wet-process acids or superphosphates, the acidulation of certain minerals may cause foaming and formation of sludge, filtration, corrosion, and handling problems.

Jan 1, 1978

By Sam H. Patterson

Fuller's earth and bentonite are two clay commodities that are interrelated either by mineral composition or use. Because of this interrelation and the sale of both for many different uses, some ambiguity in their classification has resulted. The term "fuller's earth" has no compositional or mineralogical meaning, and it is used more or less as a catchall for any clay or earthy material suitable for certain uses. Most, but not all, of these uses require absorbent properties. Bentonite by geologic definition must have formed from volcanic ash or tuff or the glassy material in volcanic rock; most bentonites consist chiefly of montmorillonite but other clay minerals may be present. In industrial usage the term "bentonite" is applied to any clay consisting chiefly of montmorillonite, irrespective of origin. Georgia and Florida have historically been the leading States in the production of fuller's earth; bentonite has been produced in Alabama on a small scale. The first major use of fuller's earth was in refining of oils. Other materials have replaced fuller's earth for this purpose to a major extent, but many new uses for fuller's earth have been found, and production has increased in recent years. The new uses include absorbent products, insecticide and pesticide carriers, drilling mud, and many others. The bentonite now produced in Alabama is of the "southern," "low selling," or "calcium" type and is used mainly as foundry-sand bond. Most of the fuller's earth mined now is in the Hawthorn Formation of Miocene age; a lesser amount is produced from the Twiggs Clay Member and other beds in the Barnwell Formation of Eocene age. Inactive pits from which fuller's-earth was produced from other formations occur at several localities. The bentonite now mined in Alabama is in beds of Cretaceous age; several years ago bentonite was produced from Eocene beds in this State.

Jan 1, 1972

By Steven J. Schatzel, Mark M. Mazzella, Robert A. Kimutis, VASU GANGRADE, James D. Addis, Marcia L. Harris, Mayley Guitard

Researchers from the National Institute for Occupational Safety and Health (NIOSH) evaluated the impact of potential shale gas well breaches and subsequent gas inflow on selected mine ventilation systems of operating longwall panels using a 1:30 scaled Longwall Instrumented Aerodynamic Model (LIAM) and Sulfur hexafluoride (SF6) as a tracer gas. A series of tests were performed at 340, 400, and 500 cfm inflow levels utilizing different mine ventilation scenarios. Results suggest that the breached gas can be diluted to meet statutory levels when the longwall panel is adequately ventilated. The results enhance the understanding of the gas inflow and mine ventilation system interaction and provide critical information to the industry and regulatory agencies for improving miners’ safety.

Feb 1, 2024

By Yuanbo Zhang, Yikang Tu, Zijian Su

Stainless steel swarf is a typical by-product produced from stainless steel processing, which contains a significant level of valuable metals, such as iron, chrome, and nickel. About 1 million tons of stainless steel swarf are generated in China annually, but as mixed with impurities such as Al and Si, stainless steel swarf is not suitable to be directly smelted into stainless steel through refining process. In this study, stainless steel swarf was applied as a strengthening agent during limonitic laterite sintering process. The effects of adding stainless steel swarf on green bed permeability, the yield and quality indexes of the sinters, and the microstructure of the sinters were evaluated systematically. The results showed that the concentrated distribution degree of granules and green bed permeability were improved after adding stainless steel swarf. As the additional amount of stainless steel swarf increased from 0 to 3%, the tumble index and yield of the sinters rose from 50.07 to 54.69% and from 62.04 to 67.35%, respectively. The addition of stainless steel swarf would not change the phase compositions, and had little adverse impact on the metallurgical properties of the limonitic laterite sinters.

Aug 23, 2023

By R. Sharon

Barrick Goldstrike Mines, Inc. Betze-Post open pit operations, located in northeastern Nevada, have experienced slope instability attributed to the presence of generally weak rock mass conditions, local adverse structural geology and perched groundwater. Ground movements are monitored with acombination of optical survey, extensometers, inclinometers, and time domain reflectometry (TDR).The slope monitoring system at Goldstrike includes two robotics theodolites, which provide real-time coverage for all highwall areas. Survey instruments are housed in specially designed climate controlled shelters in locations where all slopes can be observed. A “remote” computer housed with each theodolite collects data. The “base” computer, located in the mine offices, is used to access data from the remote computers via radio modem.

Jan 1, 2000

By C. A. Pryor

The aggregates industry is the largest minerals industry in the United States producing over 2.6 billion metric tons of crushed stone, sand and gravel annually. Approximately 5% of that production is fine material, passing a 75-micron mesh sieve. Of that amount, about 77% is not sold and represents one of the major industry issues. The material accumulates in stockpiles and settling ponds having an operational and economic impact on the site’s bottom line. Many factors cause this material to be produced: from blasting and processing techniques all the way to end use specifications.

Jan 1, 2002