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By S Hapugoda, M Kilburn, M Adam, L Lu

Lump ore is one of the key ferrous materials used in the blast furnace ironmaking process, typically accounting for 5–25 per cent of the blast furnace ferrous burden. Like other ferrous materials, the characteristics of lump ore have an important impact on stable operation and productivity of a blast furnace. As the cold burden lands on the top of the hot burden in the furnace and descends, it is inevitably subjected to thermal shock, which will likely lead to breakdown of the lump particles, or decrepitation and affect the gas permeability inside the blast furnace adversely. An ISO decrepitation test has therefore been developed to assess this behaviour of lump ore. However, the results obtained according to the existing standard decrepitation test method vary considerably between laboratories even for the same lump ore. To improve the test procedure of the existing decrepitation test, this paper first discusses the mechanisms leading to decrepitation and then studies the factors affecting lump ore decrepitation. Understanding the key factors affecting lump ore decrepitation is particularly important to improve the existing test procedure that enables researchers to achieve a higher degree of precision when conducting the decrepitation test.CITATION:Lu, L, Adam, M, Hapugoda, S and Kilburn. M, 2017. Decrepitation of lump iron ores, in Proceedings Iron Ore 2017, pp 91–96 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 24, 2017

By H. Akbari

The ordinary Portland cement (OPC) is the key pozzalonic component of the concrete mix, widely used as the construction material world-wide. Billions of tons of OPC are used in the construction industry each year. However, calcinations of limestone and silica that produce OPC also produce almost an equal amount of CO2 during the cement manufacturing process. Thus, OPC production accounts for nearly 7% of all anthropogenic CO2 emission each year. The main objective of this study was to develop a geopolymer-based composite to be used as a substitute for OPC in concrete application to significantly lower the carbon foot print of the construction industry. A waste material produced during the coal combustion process was used as the main raw material for the geopolymer-based composite. It was mostly the non-metallic content of the F-type fly ash produced from the combustion of bituminous coal. The authors envisioned to extract some of the valuable metal oxides from fly ash prior to using the major non-metallic portion of the fly ash for geopolymer concrete application. The results obtained from this study exhibited that the compressive strength of the geopolymer concrete compares favorably with that of the conventional concrete prepared using the OPC.

Feb 27, 2013

By W. Lum

In the U.S., flexible metal pipe culverts are designed by ring compression theory because the pipes are capable of deflecting and deriving side support from surrounding ground. For economy, tunnel liners are often designed as flexible structures that depend on the lateral pressure of the surrounding ground to maintain stability. In this paper, simple formulas are presented to determine the maximum deflection a concrete tunnel liner may assume and the ring compressive strength of the deflected liner. A tunnel can then be constructed to work within these limits. Similar techniques may be used to design concrete pipes.

Jan 1, 2010

By John F. Spence

Ever since opening, the M25 motorway to the west of London has carried a rapidly increasing volume of traffic. The section of M25 between the junctions with the M3 and M4 motorways, which is in the near vicinity of Heathrow airport, is the most heavily trafficked section. Piling and ground treatment was required for motorway widening works over this route, which is 7 miles long. The foundation works were undertaken next to the live motorway and beneath the flightpath for aircraft landing and taking off at the airport. The paper describes the foundation construction techniques used, and the how the methods were affected by the live motorway and the height restrictions imposed by the airport. A unique method of piled retaining wall construction is also described.

Jan 1, 2007

A comparison is made between elementary block estimation techniques and the optimal methods of geostatistics using data from an Australian deposit. Considerable improvement in the estimates are obtained by using the optimal technique in this case.

Jan 1, 1975

By Enrique Mansilla Navarrete

El presente texto describe las investigaciones recientes sobre el uso del caolín como "rellenador" en las diferentes industrias y artes. Los "rellenadores" o "fillers" son materiales qúimicamente inertes, cuya acción es básicamente física. Entre las características de los "fillers" tenemos la densidad aparente, tamaño de partículas, capacidad de absorción, abrasividad, porosidad, comportamiento térmico y una velocidad de sedimentación adecuada. De acuerdo a estos parámetros señalados, se desarrolla un programa exploratorio, los métodos empleados y la descripción de su uso en algunos depósitos encontrados en Cajamarca.

Nov 8, 1982

By G. L. Oldright

As sponge iron is much like porous, coarse sand, it is a tempting material to use in place of coarse scrap iron as a precipitant of metals, for scrap iron is relatively awkward to handle and exposes only a small amount of surface to pregnant solutions. The results of the experiments described in this bulletin are largely a record of the behavior of sponge iron as a precipitant of lead and copper under laboratory conditions comparable to those that would obtain in a commercial plant were it attempted to secure the maximum contact of surface between solution and precipitant. Physically, the study is largely one of the rates of diffusion of the metal ions in the solutions and through the metallic coatings surrounding the sponge iron particles. The practical objectives are to remove completely the valuable metals from solution and at the same time to obtain a precipitate of good grade. In order to fulfill this latter requirement, the precipitant should be almost completely consumed. These practical ends are usually secured by having the two substances involved pass each other counter-currently-that is, in such a manner as to have the strongest precipitant in contact with the most impoverished solution, and vice versa. EXPERIMENTS WITH LEAD SOLUTIONS In nearly all of the schemes involving the leaching of lead from its ores the metal has been put into solution as the chloride, and fairly concentrated liquors have been employed. The solubility of lead under such conditions is comparatively small at best; the hot pregnant liquors from which the metal is to be precipitated are then made nearly saturated with respect to lead, and only a very small amount of acid is used. Therefore it was not as necessary to learn the behavior of the sponge iron in precipitating lead from solutions of widely differing composition as to learn under what conditions, and with what mechanisms, this precipitation might be carried out most readily.

Jan 1, 1928

By W. D. Walker

The trend toward encouragement of worker participation in accident prevention in the coal mines of the United States is not new; however, it has been given added impetus in recent years and is now definitely progressing. It has been found by experience that, although there are many approaches to a mine-safety program that will include the workers themselves as well as their supervisors, no one way is suitable under all circumstances. It requires the concerted efforts of many agencies working along parallel lines toward a common goal. The following seven principal agencies, using somewhat different methods, are listed to illustrate how this problem is approached throughout the coal-mining industry 1. Federal Bureau of Mines. 2. State mining departments (in individual States where coal is produced). 3. Programs conducted by individual mine operators. 4. Programs conducted by mine workers' organizations (unions). 5. Institutes, societies, and other educational organizations. 6. Coal operators' associations (regional and national). 7. Universities, college, and high schools. Each of the seven approaches to safety are discussed briefly, and their methods end contributions, such as publications and other activities, are listed.

Jan 1, 1953

By G. Broadbent

It is an honour to be invited as a speaker to this ICCR conference and a pleasure to be with you here in South Africa. I have been asked to talk about the competitiveness of coal versus other energy alternatives. Coal supplies nearly one-quarter of the global primary energy. Its most direct competitors are gas, nuclear and renewables. Oil is predominantly for transport fuels. Fuel oil is competitive with coal when crude is below its long-run average price and has some niche opportunities. But I will confine my comments to nuclear, renewables and particularly natural gas as the most potent current competitive threat to coal. Competitiveness is more than just cost and price; there is environmental acceptability, security or reliability and increasingly image. These factors are more of a spectrum than discrete issues. Dollars and cents remain the key issue for competitiveness but one must recognize the impact of politics in sustainable development and energy security.

Jan 1, 2001

The Bureau of Mines analyzed the cycle of secondary gold to determine the quantity of gold not being recovered from scrap, and to identify areas for research to increase the supply of gold from scrap. Secondary gold in 1967 was estimated to be 2.4 million troy ounces; this excludes secondary gold which is recycled within consuming plants. Firms contacted included consumers using about 41 percent of the gold in 1967, And refiners that recovered about 90 percent of the secondary gold. Results of the study indicate that loss of gold is small, and refiners and consumers are accelerating programs designed to reduce recovery costs. With the increasing generation of low-grade industrial scrap, research is needed to improve present recovery techniques and to develop methods to accelerate the flow of secondary gold back to supply.

Jan 1, 1970

By Robert A. Bauer, Paul B. DuMontelle

In 1985, participants of the multi-year Illinois Mine Subsidence Research Program conducted surveys of subsidence effects on crop production from current high-extraction mining methods, selected a site to characterize the profile, strain, fracture development in overburden materials and changes in aquifers produced by subsidence from high-extraction mining, characterized floor materia1 s in three mines, and established bibliographic reference and data base files. The Illinois State Geological Survey, University of Illinois at Urbana-Champaign, Southern Illinois University at Carbondale, Illinois Department of Mines and Minerals and Twin Cities Research Center of the U. S. Bureau of Mines are coordinating State and Federally funded research.

Jan 1, 1986

By Chaoxun Zhao, Daniel Tao, Craig Blue, Narendra B. Dahotre, Rick Honaker, Bhupendra K. Parekh, Hongyang Han

Equipment wear and corrosion have significant adverse impacts on the operating cost and efficiency of mineral processing plants. In this project advanced surface enhancement technologies are being investigated to decrease the wear and corrosion rate of metal surface. Enhanced metal surfaces are achieved through surface conversion, enrichment, and coating by use of advanced High-Density Infrared (HDI) and other technologies. Studies have been done to determine the effects of process parameters on surface properties and identify optimum conditions. The microstructure of the enhanced metal surfaces was characterized by SEM, EDS, and microindentation. Laboratory wear testing was carried out to investigate the wear performance and the viable coating candidate was determined.

Jan 1, 2005

By Hebi Yin

A two-dimensional multi-scale solidification model was developed to study the heat transfer, fluid flow, and grain growth occurring in the molten pool during the laser engineered net shaping (LENS) process. This model coupled the finite element method to calculate mass, energy and momentum transport in the macroscale with the cellular automaton technique to calculate liquid/solid phase change at the microscale. The validation of the model was performed by comparing the simulation results with experimental data from previously published works, showing good agreement in temperature distribution and the dendrite morphology (size and shape). The simulation results showed that Marangoni convection, caused by the temperature gradient along the pool surface, played a critical role in determining the flow pattern in the molten pool and exerted influence on the pool size and shape. It was also found that columnar dendrites can be formed, with dendrite arm spacings as fine as a few microns due to the high cooling rate during the LENS process. In addition, the influence of fluid flow on the dendrite growth in the pool was discussed.

Jan 1, 2010

By R. J. Watson, A. H. Juch

About half a million sucker-rod pumps are installed in oil wells in the U. S. alone. In Venezuela, too, the system is widely used; some 5,000, or 90 percent, of Cia. Shell de Venezuela's wells produce a total of 400,000 BOPD by this method. Most of the crude pumped is viscous, gassy and contains relatively small amounts of free water. API gravities vary from 90 to 16O; dead oil viscosities vary from 10 to 10,000 cp at the pump; and GOR's range from 100 to 2,000 cu ft/bbl. Pumps are set at depths ranging from a few hundred to 6,000 ft; the average setting depth is about 2,500 ft. From the literature, it appears that although recent years have seen significant progress toward understanding the rod pumping system as a whole, relatively little attention has been paid to those key items, the sucker-rod pump and the subsurface gas separator or gas anchor. Perhaps because of proration in the U. S., pump manufacturers have seemingly concerned themselves more with the durability of their product, achieved mainly through robust design and metallurgical know-how, than with its working efficiency. In 1963, CSV commenced a major rehabilitation and expansion of its heavy oil fields along the Bolivar Coast. The advent of the more efficient gravel-packed completion and of large-scale thermal recovery (mainly steam soak) operations resulted in well potentials *Now with B. I. P. M., The Hague, The Netherlands. greater than pump capacities. Hence, an urgent need arose to improve over-all pump efficiencies and to attack those special problems related to the production of both the extremely viscous and the hot, steam-laden crudes that formed an increasing proportion of the total stream. There followed a detailed investigation and testing program, carried out in close cooperation with a major pump manufacturer. This culminated in the introduction to the oil industry of a new line of sucker-rod pumps. Early Investigations and Experiments Field Tests Extensive field tests were carried out in three primary Bolivar Coast wells with an in-situ dead oil viscosity ranging from 400 to 6,000 cp. In these installations provision was made to (1) monitor bottom-hole pressures below, in and above the pump by means of pressure transducers, and record casing- and tubing-head pressures continuously; (2) measure accurately the annulus gas, as well as measure the tubing gas and liquid production from the well; (3) take special PVT samples of the well fluid; (4) measure power consumption of the prime mover; and (5) measure the rod loads at the polished rod. A typical test installation is illustrated in Fig. 1. It was established from the pressure transducers that with viscous oils, there is considerable flow resistance across the pump and gas anchor assembly. Pressure surges were observed over each pump cycle,

Jan 1, 1970

By John Dasher

The analyses reported on in this paper indicate that there are hydrometallurgical routes from sulphide concentrates to copper that are potentially competitive with smelters which are not permitted to emit sulphur oxides. The various hydrometallurgical processes, and their economics, are discussed.

Jan 1, 1973

This report describes the new Bureau of Mines Core Repository System (CORES) and presents the methods for selecting, processing, and storing physical samples and descriptive data for future reference by earth scientists. The system preserves splits of chip samples and longitudinally sliced segments of core. A records retrieval system provides for storage of data on microfilm and magnetic tapes and uses the keysort parameters of location and commodity for the identification of data.

Jan 1, 1978

By P F. Lauricella, D Hendri

In the Mesel sediment-hosted disseminated gold deposit, the spatial distribution of hydrothermal alteration is controlled by steeply dipping faults and shallowly dipping lithologies. Hydrothermal alteration of carbonate rock is characterised by decalcification, dolomitisation and silicification. Intense argillic alteration occurs in a laccolithic andesite intrusion adjacent to decalcified and silicified carbonate units. Sulphide minerals (pyrite, realgar, orpiment, stibnite and cinnabar) accompany hydrothermal alteration and precious metal mineralisation. The trace elements Ag, As, Sb and Hg are zoned spatially throughout the deposit. Mesel contains a mineable gold reserve of 7.8 million tonnes at 7.3 g/t Au. Gold mineralisation is preferentially localised in carbonate rocks adjacent to and beneath the andesite intrusion. The ore body consists of a central, near-vertical, high grade 'feeder' system flanked by tabular, inward dipping, moderate grade 'ouflow' zones. Mineralisation is controlled predominantly by two steeply dipping faults with high grade (=10 g/t) gold zones centred about structural intersections and fault splays. Gold is submicron size and locked in very fine grained (<10 microns), disseminated and fracture-controlled arsenical pyrite. The Mesel deposit developed where high angle faults guided ascending, sulphidising fluids into reactive carbonate stratigraphy adjacent to and beneath the andesite intrusion and during subsequent migration of the auriferous fluids along 'outflow' channels. Early decalcification and dolomitisation enhanced porosity and permeability prior to silicification and sulphidation. Gold deposition occurred late in the genesis of the deposit.

Jan 1, 1995

By Natesa I. Jayaraman

A field study was conducted by the Bureau of Mines to determine the feasibility and effectiveness of a secondary ventilation system retrofitted onto an Eickhoff EDW 340L double-drum shearer as a technique for controlling respirable dust generated during a longwall mining operation. An airflow duct was formed by enclosing the bottom of the undercarriage with steel plate and cutting air channels through the ends of the undercarriage frame. Air intakes were provided behind each cutting drum and at several locations along the undercarriage. Grills were installed at the intakes to prevent the broken coal from entering the ducting. A dust collector consisting of 5,000-ft3/min fan, water sprays, and a minicyclone panel was installed on the shearer at the tailgate end. Field results indicated that the secondary ventilation system reduced respirable dust more than 60% along the face. Reduction was less near the intake airway and when secondary dust sources occurred.

Jan 1, 1977

By A. C. Smith

The U.S. Bureau of Mines constructed a large-scaJe facility to study the self-heating of a large coal mass under conditions that simulate a gob area of a mine. The insulated coal chamber can hold up to 13 short tons (st) of coal and is provided with a forced ventilation system and computer-controlled temperature and gas measurement systems to monitor the heat and mass transfer phenomena that occur in the coalbed. Three experiments were completed with high-volatile C bituminous coals that exhibited high spontaneous combustion potentials in laboratory-scale tests. In the first two tests, a sustained heating was not achieved. In the third test, temperatures throughout the coalbed increased steadily from the start, with thermal runaway occurring near the center of the coalbed after 23 days. The thermal reaction wne then moved toward the front of the coalbed. The results of these tests showed that the self-heating of a large coal mass depends not just on the reactivity of the coal, but also on the particle size of the coal, the freshness of the coal surfaces, the heat-of-wetting effect, and the availability of O2 at optimum ventilation rates.

Jan 1, 1991

By J. M. Mitchell

Kuala Lumpur, Malaysia is underlain by karstic limestone. Firm clays, mudstones and siltstoncs of the Kenny Hill Formation overlie the limestone for about two thirds of the city. The remaining third has deep deposits of very soft alluvium, or tin mining slimes, overlying the limestone. It is only recently that large buildings have been constructed in the area. Arup Jururunding have been concerned with several projects located on the limestone, although space here only permits the description of four sites in detail. The experience has allowed the development of a design approach for the foundations. The aim is to make the architectural scheme compatible with the geology. This is not always possible, and examples are given of both situations. The case histories give examples of compensated foundations, and piled foundations include steel H-piles, precast concrete piles, micropiles, bored piles with rock sockets, and barrettes up to 90m deep.

Jan 1, 2010