Search Documents

By D. Stone

"The Beal Mountain mine near Anaconda, Montana, is an interesting case history of a mine that has continued operations despite several large pit wall failures over a period of approximately 10 years. The largest event involved some 3.9 million tons of rock that has moved steadily at a rate of about 0.05 ft/day since 1992. This paper documents the geotechnical instrumentation and monitoring programs implemented at Beal to provide the company with a comfortable baseline that supported ongoing operations. The success and failure of a variety of stabilization measures will be discussed, along with typical instrumentation responses for several significant events. The success of Beal Mountain serves as a good model for mines faced with serious geotechnical challenges."

Jan 1, 2002

By F. L. Pirkle, D. L. Pirkle, E. C. Pirkle, W. A. Pirkle

Heavy minerals have been mined from the sands of the United States’ Atlantic Coastal Plain since the early part of the twentieth century. Production of ilmenite from beach sands near Mineral City (Ponte Vedra), Florida, began in 1916. The first reported large-scale recovery of zircon in Florida was reported from this deposit in 1922 and of rutile in 1925. These operations ceased in 1929. Today the Ponte Vedra Country Club and Golf Course is situated in the center of the former mining site. In 1942 heavy-mineral operations were established on 202 hectares of land situated in Duval County, Florida. The location is about 16 kilometers east of the center of Jacksonville, Florida, in an area known as Arlington. This operation demonstrated that low-grade sand containing only 2 to 3 percent titanium minerals could be concentrated economically with the Humphreys spiral and that the oxides could be separated from the heavy silicates by electrostatic methods. Much of this area is now covered by a large mall and is a major retail- commercial center. Between 1958 and 1964 the Skinner tract, a deposit about 4 kilometers south of the above deposit, was mined. Today the area of this deposit is known as Deerwood, a gated country club community on the southside of Jacksonville. Further inland, E.I. du Pont de Nemours and Co. has been mining heavy minerals from a physiographic feature known as Trail Ridge since 1948, and a deposit near Green Cove Springs, Florida has been in production since 1972. Since the start of heavy-mineral mining in the southeastern United States, nine heavy-mineral ore bodies either have been or are being exploited in Florida and Georgia. Other deposits either have been lost to mining or are yet to be mined. These deposits have different origins. Some formed along shorelines at the heights of marine transgressions while others formed on regressional beach ridge plains during periods of temporary stillstands or slight transgressions. These different origins are reflected in the chemical and physical characteristics of the deposits. Ilmenite in older, more western deposits has a higher TiO2 content than ilmenite in younger, more eastern deposits. TiO2 content does not very with north-south direction. Garnet and epidote are absent or rare in the older Trail Ridge deposits, but progressively become common in the younger Duval Upland, Crestal Pamlico, and Holocene deposits. Grain size is coarsest for Trail Ridge sediments and finest for sediments in Duval Upland and Crestal Pamlico deposits. The average grain size for Holocene deposits is intermediate between Trail Ridge and Duval Upland deposits. The two models for the origin of the heavy-mineral deposits – deposits formed at the height of major marine transgression; and deposits formed during periods of temporary stillstands or slight transgressions that occur during a general marine regression; - are consistent with known sedimentological data and depositional trends.

Jan 1, 2005

By J Lyall Workman, Peter N. Calder

"Large hole rotary drilling is one of the most common methods of producing blastholes in open pitmining. Large hole drilling generally refers to diameters from 9 to 17 inch (229 to 432 mm), however aconsiderable amount of rotary drilling is done in diameters from. 6% to 9 inch (165 to 229 mm). Thesesmaller diameters are especially prevalent in gold mining and quarrying."

Jan 1, 1996

By Henry P. Chandler

COMBINED sales of abrasive materials in the United States during 1956 increased at about the same rate as the value of the Gross National Product in terms of 1954 dollars,3 which was nearly 3 percent. However, some segments of the industry did not follow the general pattern. Sales of abrasive grinding wheels increased 9 percent in value. Sales of surface-coated abrasives declined 5 percent in quantity hut increased 1 percent in value, Production of crude silicon carbide in the United States and Canada advanced both in tonnage and value, but that of abrasive-grade [ ]

Jan 1, 1958

By M. Kuchta, A. Newman

LKAB’s Kiruna Mine, located above the Arctic Circle in northern Sweden, is the second-largest underground mine in the world today. The orebody is a world-class high-grade magnetite deposit, from which three raw ore products are extracted. We use mixed integer programming to determine a production schedule, i.e., which production blocks to mine, and when to start mining them, so as to minimize deviation from planned production quantities while adhering to the operational constraints of the mine. The resulting model contains thousands of binary variables and a commensurate number of constraints, precluding us from obtaining a schedule in a reasonable amount of time. We describe a method that builds on prior, related work, to expedite solution time. Keywords: underground mining, production planning, optimization, integer programming

Jan 1, 2003

By Doss H. White

In 1989, Alabama's nonfuel mineral industry produced a State record of $463 million of nonfuel mineral commodities, an increase of $4 million over that reported by the State's mineral producers in 1988. The new record marked the fourth consecutive year in which mineral production increased over that of the previous year. Alabama ranked 22d among the States in total mineral value. Cement, stone, and sand and gravel were the three leading mineral commodities produced, accounting for 77% of Alabama's total mineral value. During the year, there were several acquisitions by Alabama cement and stone companies, and the only tantalum mine in the United States completed its first full year of operation.

Jan 1, 1991

This paper discusses the application of a computerised model based on genetic algorithms (GAs), called GenRel, for reliability assessment of underground mine hoisting systems. The purpose of this paper is to investigate whether GenRel can be applied to predict future failure data of a mine hoisting system based on historical records of failures. The incentive of selecting the GAs for prediction of failures is that GAs are a class of evolutionary algorithms which imitate the biological evolution procedures such as reproduction, selection, crossover and mutation. The reliability of mining equipment changes over time due to an array of factors (eg equipment age, the operating environment, number and quality of repair). These factors affect the equipment's failure patterns and have complex impacts on the equipment's reliability characteristics. The failure patterns are assumed to follow a biological evolution process, and thus GAs can be considered applicable in the modelling process.To conduct the reliability assessment, a study was carried out with historical failure data of hoists in the time period from January to December 2007. Two failure data sets of two mine hoisting systems were collected from two typical underground mines in Ontario, Canada, which are denoted as the NA mine and the SB mine. The failure data sets were prepared in the format of time between failures (TBF). Then, these data sets were entered in GenRel to generate predicted failure data sets for the period of January to March 2008. The paper discusses the statistical similarity of the actual failure data sets for the period of January to March 2008 with the predicted failure data set generated by GenRel in the same time period.

Dec 6, 2010

[Pumps: oil-well: plunger: essential parts, G26, 130; 74, 828 improved type, 74, 846 leakage, 74, 837 operating cycle, 74, 833 Uren design, G26, 145 sucker-rod failures, G26, 136 sucker-rod stress, 74, 835 sucker rods, 74, 830, 832 tubing, 74, 833 tubing difficulties, G25, 138; 74, 836 Olivite, 73, 337 valve and seats, 74, 832 Punching: Monel metal, 78, 86 nickel, 78, 86 Punjab. See Indian Empire. PUPIN, M. L biography, M26, 113 John Fritz medalist, 1931, M81, 499 recipient of Washington Award, M28, 155 PURDY, R.: Discussions: on Relative Efficiencies of Domestic Fuels in Relation to Their Costs and Their Advantages 108, 353 on Uses on Coal in the Ceramic Industry, 108,389,398]

Jan 1, 1936

By F. N. Kissell, C. D. Litton

Abstract-This study predicts the level of smoke that miners might meet while trying to escape a coal mine fire and describes how smoke would impede their safe escape. For this study, the authors assumed that miners exit through an escapeway adjacent to the burning entry, that some air would leak from the burning entry to the escapeway. The following conclusions were made: • A very low amount of air leakage to the escapeway can produce a critical level of visual obscurity from smoke. This shows that intake airways may be as susceptible to smoke visibility problems as return airways. • This critical level of smoke obscurity is reached much before a critical level of carbon monoxide is reached. • Small fires can cause a severe sensory irritation that further limits vision. Thus, reliable eye protection is very important. These results show that methods to guide miners through dense smoke will contribute greatly to saving lives during mine fires.

By G. J. Joy

Although rates of pneumoconiosis in coal miners have declined substantially in the United States since the passage of the Federal Coal Mine Health and Safety Act of 1969, new cases continue to occur, including cases of rapidly progressive disease. In contrast, Australia?s underground coal mining industry has reported few new cases of pneumoconiosis for over twenty years. Mortality from Coal Workers? Pneumoconiosis in official health statistics and the prevalence of pneumoconiosis among miners screened in x-ray surveillance programs are also lower in Australia. To understand this disparity, the National Institute for Occupational Safety and Health was requested by both industry and labor stakeholders to examine this issue, with the ultimate aim of reducing the rate of pneumoconiosis among United States coal miners. A number of factors, including coal dust exposure, silica exposure, and coal rank were examined as potential contributors to the above observed differences. Comparison of coal rank data from each country did not show any significant differences. Air sample data from the coal mining industries in both countries show that coal dust levels in Australian mines are somewhat higher than those reported in similar U.S. mines; however, quartz exposure for Australian miners is lower than for many U.S. miners. Assuming that quartz is contributing to the greater number of cases of advanced pneumoconiosis in the U.S., more effective dust control measures, as well an independent exposure standard for respirable quartz in coal mining, need to be implemented to prevent this potentially disabling condition.

Jan 1, 2011

By Fábio de São José

Sistemas de moagem são projetados baseando-se, entre outros parâmetros, no consumo de energia das rotas existentes. Consideram-se custos com energia um desafio para a indústria mineral, pois a maioria da energia disponível ao processo é inevitavelmente absorvida pelos equipamentos e somente uma menor porção é destinada à fragmentação desejada. Hoje, a maioria das teorias utilizadas na avaliação do desempenho energético parte dos estudos de pesquisadores como Fred Chester Bond. De acordo com Bond, Work Index (WI) é um parâmetro representativo da resistência à moagem do minério, servindo para medir o consumo de energia na fragmentação e para comparar o comportamento de diferentes minérios. Estudos recentes comprovam que o WI de materiais em mistura pode ser medido, geralmente, com alto desvio devido às diferenças existentes de moabilidade de cada tipologia. Este trabalho consistiu na determinação do WI de minério de zinco silicatado com elevações nos teores de esfalerita (ZnS) e galena (PbS), devido à avanços na lavra, minério composto unicamente por willemita e suas misturas. Valores encontrados mostraram que a presença significativa de minerais de classes distintas daquele predominante na frente de lavra pode influenciar na determinação de parâmetros importantes para o processamento mineral. Amostras foram fornecidas pela Votorantim Metais Zinco.

Aug 8, 2018

By D Kepert, C Simpson, D Edwards

Channel iron deposits (CID) currently supply over 40 per cent of the seaborne iron ore trade out of the Hamersley Province. The two well documented producing systems (Robe and Marillana palaeochannels) were both discovered during early reconnaissance mapping principally by BHP Billiton (BHPB) and Geological Survey of Western Australia (GSWA) during the mid 1950s to early 1960s. Both crop out extensively over the majority of their length. Hot on the heels of Fortescue Metals Group 2004 - 2005 discovery of approximately 2.6 billion tonnes (Bt) of undercover iron ore mineralisation in the Chichester Range, the Fortescue Exploration Department turned its attention elsewhere throughout the Hamersley Province. Reappraisal and analysis of publicly available data and ground truthing of developing models led to the recognition of the Solomon palaeochannel system. Subsequent exploration defined a world-class Resource of some 1.9 Bt of iron ore mineralisation of which the great majority is buried CID. Apart from the Marillana CID system, the Solomon region is the only major CID with significant tonnes of sub two per cent alumina CID with over 500 Mt delineated to date. Exploration has also outlined significant supergene bedded and detrital iron ore mineralisation. Ongoing drilling is expected to increase the resource base both in terms of tonnes and confidence. This paper outlines the principal contributing factors which led to the discovery of the Solomon CID and compares its geology with the Robe and Marillana palaeochannel systems.

Jan 1, 2009

By R. Oler

The need for yieldable ground support, particularly in high stress or deep mining conditions, has grown in recent years. This paper highlights some of the current industry limitations and provides selection criteria for a new yielding ground support system, DSI?s Dynatork Bolt. This bolt distinguishes itself by withstanding 16 ? 30 kJ of energy deflecting loads anywhere from 7 ? 20 tons (depending on the energy). A summary of the laboratory test results and case studies will also be presented as a measure of the performance of this dynamic product.

Jan 1, 2012

Lead Removal from Contaminated Soils with Chelating Agents

Sep 13, 2010

By Brian Wingfield, Greg Williams, Richard W. Givens

Application of required energies into the rig design can have a dramatic impact upon productivity. Computer modeling of these production variables has led to changes in design with values closely approaching actual field data. Knowledge of these required energies can also specify the proper drilling technique to the application. With this knowledge, productivity-to-cost ratios can be determined with the most efficient option chosen.

Jan 1, 1995

By M. Botz

For leach solutions containing primarily free cyanide, the silver nitrate titration method is a rapid and acceptably accurate means of analyzing for cyanide. However, in leach solutions containing elevated levels of copper, the titrimetric method significantly over-estimates the concentration of free cyanide and under-estimates the concentration of weak and dissociable (WAD) cyanide. The authors have developed a modified potentiometric titration method for determining WAD cyanide that overcomes issues with high copper levels in solution. The new MP-WAD method involves addition of a chemical ligand to the sample prior to silver nitrate titration to fully release cyanide bound to copper. Once released from copper, cyanide in solution is no longer affected by the presence of copper and titration results are quantitative rather than empirical. In multiple laboratory trials with synthetic solutions and complex actual leach solutions, accurate WAD cyanide measurements were achieved using the MP-WAD method. Analyses obtained with the new method were found to be within about ±10% of analyses obtained with the USEPA OIA-1677 WAD cyanide analytical method.

Feb 27, 2013

By Jilai Xue, Shuming Huang, Zengie Wang

The corrosion behaviors of chrome corundum/magnesia in laterite nickel slag were investigated by static crucible method. The results show that the molten slag can penetrate into chrome corundum or magnesia which are used as lining materials in smelter furnace, and the corrosion can occur at the slag-refractory interface and the inner area of the refractories as well. Both the penetrated amount of slag and the penetration depth of Fe, Si increase with increasing FeO content (10–25 wt%) in slag. Such penetration in magnesia is stronger than that in chrome corundum under the same corrosion conditions, as more pores in magnesia may provide channels for slag penetration and corrosion product transportation. A damage of the refractory linings and short service life of smelter furnace may happen during metallurgical processing slag with high FeO content.

Mar 1, 2017

By R. Zivojinovic, S. Vujic

The structural age of the capital mining machinery, representing a part of the system of the Electric Power Industry of Serbia, has been dictated by the initiation and development of open pit coal mines. For example, the oldest bucket wheel excavators were installed some thirty-four years ago, and the average life of the relevant machinery exceeds twenty-two years. Operation of both capital equipment and machinery has direct effects on economic and business activities of open pit mines, and consequently forced us to make a decision and study thoroughly the problem of establishing the optimum exploitation life of capital mining equipment at the open pit coal mines of the Electric Power Industry of Serbia. The aim of this paper is to define and discuss the relative problems as well as to find out the possible solutions and establish the methodology for estimating the optimum exploitation life of machinery. The study was successfully carried out by a team of scientists engaged from and coordinated by the Department of Computer Science of the Faculty of Mining and Geology, University of Belgrade. This paper presents the key observations covering the subject problem. Keywords: Mining, Opencast exploitation, Coal, Optimization, Exploitation life, Capital machinery, Electric power industry, Dynamic programming.

Jan 1, 2003

By A R. Bye, T R. Stacey

Anglo PlatinumÆs Potgietersrust Platinums (PPRust) operates three open pits and plans to excavate 90 Mt of rock in 2007. With pit slopes expected to reach a height of 400 m, the geotechnical department has a key role to play. Over the last four years PPRust has successfully implemented new geotechnical strategies and tactics to reduce risk, improve safety and maximise profitability. A large database of core logging, face mapping and rock testing data has been assembled and used for failure analysis, geotechnical zoning and rock mass ratings. The data has also been used for optimising blast designs on a daily basis through the use of a geotechnical block model. This greatly improves blast fragmentation and therefore loading and milling efficiencies. The slope design process involves limit equilibrium analysis, numerical modelling, rock fall analysis and block modelling. Slope management includes comprehensive limit blasting and visual inspections, and state-of-the-art slope monitoring equipment, namely the GroundProbe radar, Riegl lasers and GeoMoS automated prism monitoring. The risk-consequence approach has been used in slope optimisation, where all the slope analyses, operational controls, costs of failure, economic analyses of various slope designs and fault tree analyses are used to determine the ideal slope designs. These activities added over $25 million of value to the operation and also ensured compliance with Anglo AmericanÆs acceptable risk level. The successful mining of the optimised slopes is to due to the greatly improved geotechnical knowledge and slope management. PPRustÆs geotechnical work is used as a benchmark for Anglo American open pit operations. The focus of the paper will be on the value added to the operation by all aspects associated with slope management.

Jan 1, 2007

By Liming Yuan

Barometric pressure changes affect air density, leading to change in the mass of the gas in the gob. When the barometric pressure decreases, the volume of gas in the gob expands, while the volume of gas contracts when the barometric pressure increases, causing the gob to breathe out and in. Although the concept of gob ?breathing? is simple, its effect on spontaneous heating of coal in the gob area is not clear. In this study, computational fluid dynamics (CFD) simulations were conducted to model the spontaneous heating of coal in longwall gob area under measured barometric pressure changes. A single longwall panel using a bleederless ventilation system was simulated. If there is no barometric pressure change, the intake airflow rate is equal to the return airflow rate. When the barometric pressure changes, these two airflow rates are no longer equal, and the difference between the two airflow rates represents the airflow rate the gob breathes in and out. The effect of inflow and outflow of gas on the potential spontaneous heating in the gob was investigated using the CFD model developed in our previous study. The effect of barometric pressure changes on the spontaneous heating was found to be dependent on the gob permeability and the coal oxidation rate. The effect of barometric pressure changes on oxygen concentrations in the gob was also examined.

Jan 1, 2010