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By Bahaa Hussein

Considerable number of methods and procedures has been introduced for trending and progress reporting of engineering, procurement and construction projects. This paper introduces a novel method, designed to augment the set of indices for measuring schedule performance. The concept behind the developed method is to provide early warning by dynamically evaluating the schedule cumulative impact of construction projects. The proposed method is designed to highlight the gradual deterioration in schedule status resulting in a cumulative impact due to the aggregation of small delays encountered during the execution of non-critical activities, and can be used as an add-on utility to existing software systems that perform CPM scheduling. The proposed method is based on a developed formulation for quantification of the Schedule Compression Index, which takes into consideration the remaining project activities durations. The index is developed based on periodic comparisons of ?Current Schedules? and the project ?Baseline Schedule? using the summation of the remaining activities durations. A numerical example is presented to demonstrate the application and capabilities of the developed method. It is expected that the developed index together with other schedule performance indices would be of value to decision makers and members of project teams.

Aug 1, 2013

By Marc Lonoff

Byproducts are more important to the copper mining companies than to the copper market. Copper ores frequently contain gold, silver, molbydenum and cobalt. With the increase in the prices of these metals copper mining has become more profitable. If byproduct prices remain high, additional firms will be attracted to the copper industry; the increased supply of copper will reduce the long-run copper price. However, this is unlikely to happen because the markets for the copper byproducts, especially molybdenum and cobalt, are small. Increased recovery from copper and other sources will depress the prices of these byproducts before the copper price is significantly affected. Should byproduct prices remain high the copper market will both settle at a lower long-run price and be more unstable in the short run. Since changes in the copper price do not affect the entire earnings of a multi-metal mine, the copper price must fall further before such mines reduce output in the short run. Higher byproduct revenues will make copper supply less responsive to copper price; shifts in copper demand will result in greater copper price fluctuations in the short run than they did before.

Jan 1, 1980

By C. H. Herty, J. K. Gaines

"Nearly every piece of electrical equipment used in mines ""breathes."" In other words, motors, controllers, rheostats, switches, and other similar equipment, even though encased in seemingly tight compartments, breathe in the atmosphere that surrounds them.As the apparatus is used, the temperature of metallic parts is changed generally in positive direction through the heat by friction and the heat due to the electric current. When the apparatus is idle it gradually cools down to the temperature of the surrounding atmosphere.This increase of temperature during operation and return to normal temperature when operation stops alternately raises and lowers the temperature of the atmosphere within the compartments which, in strict accordance with Charles' law -T = VT1 V'will expand or contract in proportion to any given temperature change.As compartments are not gas-tight, such expansion and contraction will force the atmosphere out of the compartment =on expansion and suck the surround¬ing atmosphere into the compartment during contraction, hence the term ""breathing.""Investigators of explosion-proof equipment have recognized that such an interchange would take place and have designed their equipment to safeguard possible explosions within the compartments."

Jul 1, 1927

As part of remote sensing research on an abandoned mine lands (AML) site in the Colorado Springs, Colorado area, a geographic information system (GIS) database was generated. This GIS database contains information on the locations and extents of abandoned underground coal mines, the geology of the area, subsidence features and degrees of subsidence risk, topography, drill hole locations, and lineaments (linear features) related to subsurface geologic structures. A GIS database allows the reproducible and accurate comparison and analysis of any data sets which geographically overlap and are within the same coordinate system. The database has been released to the public domain so that government agencies, researchers, educators, and the general public can access this coherent database for the purposes of better understanding the study area and GIS technology. Data files and maps are available in formats that are compatible with the GIS software used in the research project and with most CAD systems so that as many people as possible can make use of the majority of the database. This document serves as the data dictionary for the database by providing descriptions and origins of the data files.

Jan 1, 1992

By Peng Gao

Coal-based reduction followed by magnetic separation is an innovative technology used in processing refractory iron ores. Given that size is essential to the separation of the metallic iron from the gangue, the morphology of metallic iron particles and their evolution during coal-based reduction are investigated in the present work. The size of the metallic iron particle increased from 128.76 µm to 565.70 µm when the reduction time increased from 20 min to 60 min at 1,225° C and C/O (i.e., the amount of coal addition in terms of the gram-atomic ratio of the fixed carbon in the coal added to the combined oxygen in iron oxides) of 2.5. Based on our microstructural and metallographic analysis, the iron ore reduction process can be divided into three stages: (1) metallic iron particle formation, (2) iron oxide reduction and metallic iron assembly and (3) metallic iron particle growth. Almost all iron oxides are reduced to metallic iron in the second stage. These newborn metallic iron particles are energetically active and able to assemble and grow, and are eventually separated from the gangue. The large metallic iron particles benefit the subsequent magnetic separation process.

By K Koskinen, S Ronkainen

The flow field induced in an Outokumpu TankCell and by an OK rotor-stator mixing device in a laboratory and a process size flotation cell was modelled numerically using computational fluid dynamics (CFD). The primary target was to discover and reproduce the various interactions between the flow field and the flotation cell by numerical means. As power consumption depends sensitively on flow field, it can be regarded as a top-level derived quantity (or measure/metric) indicating the validity of the numerically obtained flow field. Having properly validated numerical means to produce the flow field the influence of various design parameters can be captured with certain accuracy. In addition, separate gas and solid phase models for bubbles and solids, respectively, were implemented. The comparisons between velocities and turbulence quantities measured using the laser doppler velocimetry (LDV) technique and CFD modelling were performed. The grid generation was performed with the commercial Gambit 1.3 and the subsequent integration and solving of the resulting algebraic equations with the commercial CFD-code Fluent 6.22. The computationally economic multiple reference frame method was included to model the moving rotor blades. Gas and solid phase models were modified mixture models.

Jan 1, 2005

By H. Uygucgil, C. Kwang

The use of remote sensing and geographic information system techniques in mineral exploration is still underutilised. There is a need to explore the potential of new robust remote sensing and geographic information system techniques in the field of mineral exploration. In this study, we mapped the argillic alteration associated with epithermal gold-silver mineralisation. A band ratio of band5/band6 and Crósta technique on Advanced Spaceborne Thermal Emission and Reflection Radiometer within the Google Earth Engine Environment was applied. The bands 5 and 6 were selected for the band ratio after critically analysing and comparing the illite spectral extracted from the Advanced Spaceborne Thermal Emission and Reflection Radiometer image and the illite spectral obtained from the United States Geological Survey spectral library. The band ratio and Crósta technique identified and mapped the Ovacik goldmine and other argillic alteration zones. Even though both methods mapped out the argillic alteration zones associated with gold-silver mineralisation, the Crósta technique produced the optimal argillic alteration. The study demonstrates the analytical capabilities of Google Earth Engine in image processing and analysis for mineral exploration, such as discovering hydrothermal alteration associated with mineralisation.

Jul 23, 2025

By E. W. Shaw

The past year (1950) has been a big one for the oil industry in Canada, with new records being set in almost every phase of exploration and development activity. New highs were reached in acreage holdings, in geophysical activity, in wildcat drilling, and in field development and production. The only item that did not show a substantial increase over recent years was the amount of reserves added by new discoveries. This was not due to a decrease in the number of new discoveries, however, hut rather to the fact that most of the discoveries were made during the later months in the year and could not be fully evaluated by the year end. The foregoing remarks pertain mainly to activity in Western Canada. In Eastern Canada, operations continued on a modest scale. with exploration drilling down slightly from the previous year but with development drilling and production at about the same level. Returning to Western Canada, it is observed that the general exploration play was one of expansion and intensification. The issuing of new petroleum and natural gas regulations by the province of British Columbia precipitated a moderate entry of companies into the northeastern part of the Province.

Jan 1, 1951

By M J. Pejovic, S BoÜevski, I Miljanovic, M Hudej, A Milutinovic, A Petrovski

The paper deals with the problem of managing the supplies of consumables (energy resources, lubricants, explosives, explosive supplies, tires, spare parts, etc) in mines. After the introductory remarks and comments, a general stochastic model of supply, relating in general to the dynamic programming method is presented. A selection of stochastic supply model for experiments and research by the authors of this paper is not a coincidence, based on of their long experience, showing that this type of model is the most suitable to provide support for decision-making and management of supplies of consumables in mines.In order for the problem?of?consumables?supply?management to be reviewed, in whole and objectively from the aspect of risk, experimental tests of the stochastic model in real conditions were performed at the limestone open pit mine æZelenikovecÆ near Skopje, the capital of Macedonia. The scope of the experimental research enabled reliable analysis. The results obtained confirm the efficiency and reliability of the stochastic model and two separate manipulative-operational positions regarding its application, which may have an important influence on the optimisation of supplies.

Sep 26, 2011

By W. Rocher

The Minera Ojos Del Salado (?MINOSAL?) concentrator is located 20 kilometers southeast of Copiapo, Chile and processes copper ore provided by its Santos and Resguardo mines at a capacity of 4,200 tip (4,620 stpd). Phelps Dodge acquired the majority interest in MINOSAL in 1982. The principal incentive for this purchase was the exploration potential of the property. At that time, the concentrator plant was a small, antiquated installation with a capacity of 674 t/d (740 stpd). In 1982, the majority of the ore was produced from the Santos and Resguardo mines, but custom ores of copper, silver, and gold were also treated. The acquisition occurred at a crucial time in the copper business, since the price had fallen to nearly $0.50 per pound. In 1985, Phelps Dodge purchased the outstanding interest in MINOSAL and acquired 100% of the property. Today, after numerous improvements and two expansion projects, the concentrator is an interesting combination of old and new equipment. The regrind mills, for example, have been in service for about 50 years, while the ceramic concentrate filter represents the latest technology.

Jan 1, 1993

By Clyde E. Williams

MODERN steelmaking has gradually evolved from an inefficient small-scale operation, utilizing tiny units, to a highly efficient one utilizing large units almost completely mechanized. The leading position of the United States in the steel industry is due to the possession of easily assembled high-grade raw materials and large-scale highly developed plants. Modern integrated steel operation is largely one of material handling. Mining and transportation of iron ore, coal, and fluxes, coking the coal in by-product ovens, smelting the ore with coke and limestone in blast furnaces, converting the resulting pig iron into steel in the Bessemer, or in the open hearth when supplemented with scrap, and fabricating the resulting steel ingots in the shapes of commerce all are done on a huge scale, mostly by machinery, most of the labor being employed either in operating the machine or keeping it in repair. At the same time the quality and uniformity of the product have been greatly increased by the development of scientific knowledge and operating skills. Thus, the steel industry in this country is highly developed both mechanically and technically.

Jan 1, 1942

"An experimental study has been performed to investigate the dispersed phase holdup induced by a high-strength submerged gas injection in a bottom blown air-stirred one-seventh water model of CLU (Creusot-Loire Uddeholm) reactor using two different tuyere configurations. The air flow rates varied from 0.00599 m3/sec to 0.01312 m3/sec. In these series of experiments, water height and kerosene height were kept constant at 0.23m and 0.02m respectively. The dispersed phase holdup was determined at various gas flow rates, and tuyere orientations by using water and kerosene.The dispersed phase holdup increased with gas injection rate and decreased with vertical distance from the original interface. At constant gas flow rate, as the vertical distance increased in the centerline, off-center configuration of nozzles displayed higher values of the dispersed phase holdup than those of the center configuration. The variation of the dispersed phase holdup with the dimensionless axial distance and the gas injection rate was correlated by using the Modified Froude Number. The experimental values of the dispersed phase holdup were found to be in good agreement with the calculated values obtained from the correlation equations."

Jan 1, 1999

By A. L. Engel

The sample of ore on which the work described in this paper was done came from Mina Oriente, Carrizal Bajo, Provincia de Atacama, Chile, South America, and was sent at the request of the Chil.ean Government through the Foreign Minerals Division of the Bureau of Mines. This ore had been tested locally for treatment by flotation and cyanidation without satisfactory results. An additional difficulty was the absence of water near the ore deposits, so that in any treatment method considered the water requirements would have to be very low. It was desired to develop a practical method of recovering the gold and, if possible, the copper in the area. No data of previous investigations were made available. The sample received was mostly quartz, highly brecciated, with limonite and hematite in the fractures. Copper occurred as malachite and azurite, also in the fracture s and to a slight extent as a stain in the quartz. Some fine-grained pyrite with a little arsenopyrite occurred within the quartz. An occasional grain of chalcopyrite was observed. No free gold was seen during examinations of the ore, but amalgamation indicated that some was present.

Jan 1, 1949

By W. Beres, R. E. Miller, B. Shiari, L. R. Zhao

A dynamic multiscale (MD/FE) method has been used to study dislocation generation and plastic deformation during a nanoindentation process which is physically associated with the generation of heat within the specimen and as a consequence with a temperature rise. Two different techniques are applied to study the temperature effect on the nanoindention process. In the first technique, a global Nose-Hoover thermostat is applied to the entire atomistic region to keep temperature constant during simulation (finite temperature approach). In the second method, the thermostat is applied only on a damping region along the MD/FE interface. Both techniques are able to effectively and efficiently absorb high frequency reflected waves from atomistic/continuum interface. The temperature profile of the atomistic region beneath the indenter is reported and discussed at four different initial substrate temperatures for both techniques. The loaddisplacement (load/unload) curves for different temperature-controlling techniques are compared and discussed. The nucleation and propagation of dislocations in the atomistic region are investigated for both techniques. Correlations between the observed features in the load-displacement curves with the motion and pile-up of dislocations are reported as a function of temperature.

Jan 1, 2006

By Zay Jeffries

HOSTILITIES in Europe, Asia, and northern Africa were responsible for dislocations in rare-metal supplies during 1940. Although the consumption of some of the rare metals is small the dislocations may be relatively large. In some cases these are advantageous to North America and in others they are disadvantageous. Specific instances will be cited later. Barium T HIN films of barium metal on special steel balls greatly improve the life and reduce the friction of rotating anodes in highly evacuated small X-ray tubes and make possible the operation of these anodes at relatively high temperatures. These remarkable results are described in an article by Atlee, Wilson, and Filmer in the Journal of Applied Physics for September, 1940. Oil could not be used because of the high temperatures on the one hand and its volatility on the other. Fig. 3 shows diagramatically the rotating anode and the method of coating the steel balls with barium. The letters K.I.C. refer to "Kemet Iron Clad." The K.I.C. wire was mounted so that the barium could be evaporated by direct passage of the electric current. At high temperatures the barium dif-

Jan 1, 1941

By D. A. Akinlade, N. L. Richards, D. C. Murray, W. F. Caley

To investigate the effect of adding Ti to a Ni-Cr-Fe powder metallurgy alloy, a thermodynamic software package was used to predict the phase transformations that occurred during thermal processing. Specifically, the effect of adding 3w/o Ti to a 6w/o Al modified ternary Ni-Cr-Fe alloy (the quaternary) was simulated and the phase transformations that might occur in the material on sintering were obtained using the thermodynamic modeling tool. These predictions were subsequently compared with experimental results obtained by X-ray diffraction and metallography. For comparison, selected compacts were prepared containing only the ternary + 3w/o Ti (no Al). Based upon compressibility curves, the optimum pressure for producing the new Ti compacts was 500 MPa vs 600 MPa for the quaternary composition with Ti. In each case, hardness of the base alloy was enhanced by the Ti addition whereas the residual porosity remained relatively constant at about 19%. Finally, although SEM/EDS failed to confirm the presence of Ti in the gamma prime intermetallic, XRD spectra showed a shift in lattice parameter on addition of Ti, suggesting that the intermetallic was of the form Ni3(Al,Ti).

Jan 1, 2010

By G. Ozbayoglu, Z. Ozdemir

Turkey is the main boron minerals producing country in the world. The most important boron minerals are tincal, colemanite and ulexite. All mining, beneficiation and handling operations generate fines which cause ecological and economical problems. Utilization of this accumulated material requires both upgrading and agglomeration. The aim of this research was to exploit the ulexite fines by improving their grade and size. Attrition-scrubbing followed by washing and screening was employed for upgrading the fines. It was found that the grade can be increased from 23-25% B2O3 to 29% B2O3 with 73% recovery. Briquetting was applied as the size enlargement process. During the briquetting, the effect of moisture content, pressure, amount and type of binder, and drying on the quality of briquettes were investigated. The tests showed the possibility of production of strong briquettes by adding water alone, but the briquettes had no resistance to abrasion and water. Binders, namely boric acid and borax have been added to improve the properties of briquettes. The results showed that the compressive strengths and abrasive resistances of briquettes obtained with both binders were acceptable. However, the briquettes have no water resistance properties.

Jan 1, 2004

By I. M. M. W. R. Jones

"THE OBJECT of these notes is to initiate a discussion among the members of our Institution on the connotation of the term 'ore', and to arrive, if possible, at an acceptable definition of the term in the light of its current use by our leading mining engineers, metallurgists, •and geologists.The majority of •authors of well-known modern text-books on subjects dealing with mineral deposits define 'ore' in words which convey the meaning that it is an aggregate of minerals from which one or more metals can, under favourable conditions, be extracted profitably.Many eminent members of the Institution, and of mining and metallurgical institutions in other countries, consider that the term should not be restricted to metalliferous mineral •deposits but can also be applied correctly to certain non-metallic deposits. They believe that the growth, during the twentieth century, in the industrial importance of non-metallic minerals, and the progress made in the mining and the milling of deposits containing such minerals by methods similar to those used for metalliferous mineral deposits, no longer justify the academic restriction of the term to deposits worked for their metal content only."

Jan 1, 1954

By Lawrence Pelham

The demand or consumption of fluorspar has been somewhat taken for granted in recent years, except for the specific interest of those that produce, market, and/or consume the commodity. A tradition was established of thinking that as the steel and aluminum industry goes, so goes fluorspar. This is much less true today than in the past. The industry is becoming more dependent on chemical industries that feed primarily off hydrofluoric acid (HF) production. The Bureau of Mines recently published an assessment of world fluorspar reserves and resources that created a foundation of valuable data that can be used to monitor fluorspar availability. Celebrations were held this year commemorating the 100th anniversary of the isolation of fluorine. The United States and other countries continue to struggle with the controversy of ozone depletion and the effect of fluorocarbons on the atmosphere. The goals for the U.S. Government's strategic stockpile are being reevaluated. The market for fluorine chemicals is changing and diversifying, making it a challenge to assess and forecast fluorspar/fluorine demand. This paper reviews the recent past of fluorspar and helps set the stage for a more detailed assessment of this critical commodity.

Jan 1, 1986

By Madeline Mello, Michael Low, Nick Karlin, Bryce Scofield

The LA Effluent Outfall Tunnel is the first tunnel in the United States to incorporate post- tensioning into the precast segmental lining. Several unique components were integrated to ensure that the post tensioning could be carried out successfully in the tunnel, even concurrently with the TBM excavation. This also required the development of new processes both in the casting facility and in the TBM to ensure that the almost 3,700 rings could be successfully manufactured, threaded, stressed, and grouted. This paper will discuss the material selection, fabrication, and installation of, as well as lessons learned from, this first in country tunnel lining.

Jun 23, 2024