Search Documents

Atlas Copco, a leading supplier of equipment and services to the mining and construction industries, is consistently pursuing its strategy to offer the most productive and economical solutions by continuously offering new innovative products. These are in most cases developed and tested in close cooperation with demanding end users before Being officially launched on the international market. The demands for higher productivity and improved overall economy have resulted in systems for automation of the drilling cycle and also tools for integrating the Drilling equipment to the production control system used by the customer. In terms of improving the blasted material quality, Atlas Copco has placed emphasis on hole straightness and the need for hole logging and positioning. By applying state of the art Technology to today?s computerized drilling rigs, major steps in improving overall drilling and blasting performance have been achieved. This paper will give some examples derived from the latest development of solutions for the Rotary drilling product line.

Jan 1, 2010

By E. Hulthén

Cone crushers are used in the mineral, mining, and aggregate industry for fragmentation of rock materials. Control systems for cone crusher settings are widely used to compensate for wear and to protect the machines. The eccentric speed in a cone crusher affects the number of compressions the material is exposed to and thus the particle size distribution of the product. Eccentric speed also affects crusher capacity. However, the speed of the crusher is mostly fixed, because speed changes must be made by shifting pulleys, a process which is quite time-consuming. By applying a frequency converter, which has decreased in cost during recent years, it has become possible to adjust the speed continuously. By also applying mass-flow sensors to the process, the crusher can be run optimally to yield the most sellable products in a given moment. Existing systems normally only protect the machine. The sensors can be mass-flow meters, e.g., conveyor-belt scales. To analyze data from the process and calculate the appropriate value for the speed, an algorithm has been developed. The developed algorithm was tested and evolved at a crushing plant for aggregates that produces around 350 kton a year. The algorithm was implemented in a computer that could communicate with the frequency controller, retrieve data from four mass-flow meters, and also interact with the opera-tor. The computer was reachable over the Internet for the researchers at Chalmers and the algorithm was tuned and improved on-line. The result is a crushing stage that consistently and maximally produces the most desirable product. The performance (yield of required products) increased by 4%. As a bonus, the lifetime of the mantles increased 27% on the evaluated crusher.

Jan 1, 2014

By G. France

The Blair Athol Coal Mine (BAC) is a large open cut operation in the Bowen Basin of Queensland, Australia. Current mine capacity is about 11 million tonnes per annum (Mtpa) of export coal. On-line analysis at BAC consists of two Coalscan 9500s installed directly on the output of the crusher plant and immediately before the product stockpiles, while a third Coalscan 9500 is installed on the transfer conveyor feeding the train loading bin. The two product Coals cans have a dual purpose. The first is to provide real time coal quality data directly back to the mining operations. The second is that of modeling the product stockpile with accurate on-line information. This modeling enables both production and coal quality personnel to accurately examine the coal quality of each stockpile with a degree of resolution which previously had never been achieved.

Jan 1, 1999

By M. Kinnunen

Handling of municipal solid waste (MSW) and control of its potential resources is becoming increasingly important in modern society. The OECD (Organization for Economic Co-operation and Development) average on municipal waste produced in 2003 was that of around 570 kg per inhabitant. In European Union countries around half amount is of MSW landfilled. In Finland still 88% of MSW was landfilled in 2004. Since incineration reduces MSW volume significantly while producing heat energy, it has become one of the most common waste handling techniques. The shortcoming of incineration is however, that incinerated MSW is often not pre-sorted and it produces slags and ashes as side streams from which recovery of metals is difficult. This paper looks into possibilities of scrap metal recovery for recycling from municipal solid waste incineration (MSWI) bottom ash. In order to do that, a flow sheet of physical separation methods was developed and tested with Finnish rotary furnace MSWI bottom ash. In addition, an empirical model for estimation of the recoveries of scrap metals with physical separation methods for treatment of MSWI bottom ash was developed. According to the results of this study, for 1 Mt of incinerated MSW with 30% mass reduction, a minimum resource potential of 100 kt for magnetic metal scrap of roughly 24 % grade and about 19 kt of non-magnetic metal scrap of roughly 65 % grade. In other words, 57 kg magnetic scrap and 12 kg non-magnetic scrap per inhabitant at the mentioned grades, respectively. Although wide variations of parameters affect the MSWI bottom ash quality, it can be said that a considerable amount of metals is drained into MSWI bottom ash. Results of this study show that from MSWI bottom ash significant material streams metal scrap can be reintroduced into the resource cycle which would otherwise be lost.

Jan 1, 2014

Samples weighing 0·5 g are fused with sodium hydrogen sulphate, leached with 5 ml. of 4 M nitric acid and diluted to 10 ml. with water. An aliquot of the clear solution is boiled with concentrated nitric acid and then 2 ml. of a phosphotungstate solution are added. After dilution to 10 ml. with water, the solution is heated in a boiling water-bath for not less than 10 min. When cold, the solution is extracted with 2 ml. of iso-amyl alcohol and the yellow phosphotungstovanadate complex is compared with a standard series. Concentrations down to 4 p.p.m. may be analysed at a rate of 100 samples per man-day of 8 hr.

Jan 1, 1971

Provide an effective method for "soft" soldering aluminum and aluminum alloys using conventional tin-lead solder alloys and flukes. The Problem In the past, it was virtually impossible to solder aluminum and aluminum alloys using standard tin-lead soldering systems (solder and flux) due to the presence of an aluminum oxide surface film which forms instantly on aluminum and aluminum alloys when these are exposed to air. The tenacious and stable oxide film enables aluminum-base materials to maintain their bright luster. But the film also prevents the required wetting and spreading of solder on the substrate, causing the loss of adhesion between the solder and the substrate. In addition, the heat produced during soldering increases

Jan 1, 1983

By J. -P. Lempainen, K. Haavanlammi, K. Valkama

The Outotec nickel matte chloride leaching process is especially suitable for small capacity standalone nickel refineries. The matte is leached with hydrochloric acid and oxygen in multiple steps in atmospheric OKTOP® reactors. Oxygen feed prevents reductive conditions and hydrogen formation in the leaching process. A sufficiently high acid concentration keeps the iron dissolved in the solution. The iron is removed after leaching by precipitation and the pregnant leach solution continues to metals recovery. The metals recovery from the chloride solution is done by solvent extractions, where ammonia is used for pH control. Copper and nickel are stripped from the organic phases into sulphate solutions. Metals can be recovered from the purified solution by conventional electrowinning. Other alternatives are precipitation or hydrogen reduction processes. The ammonium chloride in the solvent extraction raffinate is regenerated into ammonia. The calcium chloride solution from ammonia regeneration is routed to acid regeneration where sulphuric acid is added and ultra-pure gypsum is precipitated. The hydrochloric acid solution from this step is recycled back to leaching. The process yields good overall metal recoveries and expensive

Jan 1, 2014

By P. C. Good

The Bureau of Mines conducted a laboratory investigation of a sinter-leach method to recover aluminum and fluorine from waste carbon potlining residues from secondary cryolite recovery operations in aluminum reduction plants. After removal of carbon by burning, the residue was sintered at 900° to 1,100° C with silica and N2CO3, then crushed and leached with dilute NaOH solution, dilute Na2C03 solution, water, or water containing residual Na2O which remained in the sinter after reaction and decomposition of Na2CO3. Over 90 percent of the contained aluminum and up to 87 percent of the contained fluorine were extracted from this waste product in the form of a mixed alkaline solution. Treatment of the alkaline solution with CO2 yielded a white precipitate containing 89 percent of the original aluminum and 61 percent of the original fluorine as a mixture of synthetic cryolite and alumina, together with a variable excess of soda.

Jan 1, 1969

By Donald M. Duncan

An acceptable source of concrete aggregate is available in Kansas City in a continuous, medium bedded, slightly dipping limestone unit. Removal is accomplished in shallow depth, 12 feet to 17 feet high, room and pillar mines. The accepted empirical design spaces 20 foot pillars 60 feet on center. A portion of the 20 foot unit is left in place for roof support. Rock and soil cover is variable to 100± feet maximum. Long-term stability of these mines is affected by numerous factors, including the above mine-rock profile, ground water conditions and mining practice. Crusher-run aggregate sells at the mine for $2.20 per ton, yielding a gross income of $2.00 to $2.80 per square foot of mine. Use of mine space for real estate development requires a new perspective in mine development. Mining practices to obtain long term stabile structures can become an over-riding factor as compared with minimum production costs and maximum extraction ratios. Poorly mined areas are unusuable for secondary purposes. Development cost for lease space in less desirable mines is substantially greater than those planned for a secondary use. Real estate development in mine space involves unique engineering problems. Properly engineered developments offer singular advantages. Warehouse lease space sells for $.50 to $1.00 per square foot per year; fully developed office areas may double these values.

Jan 1, 1968

By Zainab Nasrullah, MontanaFrank Agyemang, Mehran Sadat, Richard LaDouceur

Rare earth elements (REEs) are valuable for various modern technological applications, including metallurgy, machine building, radio electronics, instrument engineering, nuclear engineering, and manufacturing. The extraction and separa-tion of rare earth elements (REEs) from their complex ores is challenging due to their distinct physical and chemical properties, contributing to their market scarcity. At present, REE recovery utilizes traditional pyro- or hydrometallurgi-cal processes. The overall process in the recovery and sepa-ration of individual elements from complex REE systems suffers from high energy demands and the use of many haz-ardous chemicals that negatively impact the environment. With the growing trend toward a circular economy aim-ing to balance sustainability, efficiency, and environmental impacts, this research is focused on using deep eutectic sol-vents (DESs): a combination of a quaternary salt: Choline Chloride and five organic acids: Oxalic Acid, Urea, and Ethylene Glycol, Lactic acid and Glycerol for the selective leaching of REEs from their complex ore which is proven to be green, selective, non-toxic, biodegradable, and cheap. The effects of different DESs and leaching time on the REE leaching efficiency were determined, and the optimum DES media were found to be Oxaline and Lactic Acid at which a leaching efficiency of 25% and 15% was achieved at 80°C respectively for cerium.

Feb 1, 2025

By A. J. Farstad

The principle objective of the research effort described herein was to identify as rapidly as possible a practical trapped miner location system. Much effort has been expended in the past on the development of a highly sophisticated seismic location system [1] for trapped miners. Field tests of this system have shown that the location accuracy is limited by a combination of seismic velocity anomalies, timing errors, and in general by the relatively weak nature of the signals received at the surface. It was first felt that similar propagation anomalies would be experienced by electromagnetic systems, but to a greater extent than the seismic. However, preliminary tests performed by Westinghouse on the Operations and Maintenance Program, Contract No. H0210063 in 1971 and 1972, indicated that an electromagnetic solution to the location problem may be more feasible than a seismic solution. Thus a more concentrated effort was launched in 1972 and 1973 to more completely determine the feasibility of electromagnetic location systems for trapped miners. Two different approaches to the location problem were undertaken on this program: (1) A pulsed electromagnetic system was developed by the Special Systems Division of Westinghouse in Baltimore, and (2) a Continuous Wave (CW) System was developed by Westinghouse Georesearch Laboratory (WGL) in Boulder, Colorado. Part I of this report will deal only with the development and results of CW Location System developed by WGL. The CW Location System was field tested at three eastern coal mines and at one western hardrock mine. The maximum overburden depth penetrated during these tests was 990 feet at the Robena No. 4 mine near Waynesburg, Pennsylvania. The earth conductivity at this mine was measured to be 1. 1X102 mhos/m, which combined with the deep overburden make this mine representative of expected worst case conditions for a coal mine EM location exercise.

Jan 1, 1973

By Leo A. Schrider

A prediction for oil recovery from a pilot waterflood in the Kane oil- field, located in Elk, Forest, and McKean Counties, Pa., was made and compared to actual field performance. Water-injection and production histories, well logs, other field data, and results from laboratory tests of core material were used in this analysis. Performance of the pilot waterflood, initiated in January 1963, was predicted using a modified Craig, Geffen, and Morse calculation technique. Maximum recovery from this low permeable, preferentially oil-wet formation was predicted to be about 22,500 barrels of oil after 300,000 barrels of water had been injected into the pilot waterflood area. After additional field data were collected it became necessary to reevaluate the pilot waterflood area. The gas saturation prior to the waterflood was estimated to have been 20 percent, based on an assumption regarding the required volume of water injected to initiate oil production. In view of the actual field performance, a gas saturation of 13 percent is indicated. When this gas saturation and the method originally proposed by Craig and others are used) the predicted results are more representative. In December 1965, field performance was further analyzed using a hyperbolic-decline curve as presented by Arps. Based upon this evaluation method, the pilot water flood in the Kane sand should produce 37,000 to 42,000 barrels of oil with the injection of 300,000 barrels of water into the pattern. By continuing this secondary-recovery project to a reasonable economic limit, ultimate oil recovery may be as much as 50,000 to 55,000 barrels, or 129 to 142 barrels per acre-foot from 36.5 acres.

Jan 1, 1967

By R Long

The founder of social psychology is sometimes identified as Kurt Lewin. In a 1947 article, Kurt Lewin coined the term ‘group dynamics’. He described this notion as the way that groups and individuals act and react to changing circumstances. Lewin theorised that when a group is established it becomes a unified system with unique dynamics that cannot be understood by evaluating members individually. The discipline of social psychology really emerged out of World War II and tackled questions associated with human judgement and decision-making by the Nazis. For a comprehensive look at the development of social psychology look at Abelson, Frey and Gregg (2004).Social psychology is concerned with the way social arrangements affect human judgement and decision-making. What the author has done is apply the knowledge of this new discipline to an understanding of risk, safety and leadership. This paper will explain some of the developments in social psychology, such as the discovery of the bystander effect, Groupthink, bounded rationality, heuristics, risk homeostasis and the Milgram effect.The social psychology of risk tackles the way decisions are made about risk in their social context. Unless organisations understand that decision-making is socially conditioned, they are unlikely to be able to tackle the complexities of culture change or the development of risk maturity.The paper will offer a new understanding of why people do what they do, how risk makes sense and why a ‘dumb down’ approach to safety is dangerous. A model will also be presented that shows the pathway to risk maturity.CITATION:Long, R, 2016. The social psychology of risk, safety and leadership maturity, in Proceedings Seventh International Conference and Exhibition on Mass Mining (MassMin 2016), pp 31–42 (The Australasian Institute of Mining and Metallurgy: Melbourne).

May 9, 2016

By Andreas Stieben, Pierre Lutomski, Wolfgang Bleck, Martin Fischer

"For steel investigation and development, exact knowledge about the microstructural state is required. The information gained from 2D images often can't properly reflect the real 3D microstructural properties. In order to gain reliable information for meaningful models, simulations and correlations, it is necessary to accompany standard metallography with 3D information, which, unfortunately, is very difficult to access. This article presents a procedure for serial sectioning in combination with light optical microscopy. Only standard metallographic tools are employed in combination with image manipulation freeware. 3D microstructural data were extracted from three multiphase steel grades and in two cases virtual 3D-models of microstructural phases were generated.Three Dimensions Of MicrostructuresSince the invention of steel, craftsmen, inventers and engineers tried to improve its properties and tailor them to the requirements of new developments. For systematic development and enhancement of steels, the capability to investigate its inner structure is highly important, because it represents the linchpin between material production and properties. By having an in-depth understanding how production conditions form the microstructure and also how the microstructural state determines the material properties, steel design can be drastically improved. With this knowledge, microstructures can be designed to provide target material properties and process conditions can be identified that form these structures. Due to the key role of microstructure, the capability to gain accurate information about it is indispensable. It is the task of metallography to access and extract descriptive quantitative microstructural data like fractions, sizes, shapes and distributions of the different constituents. The most commonly used investigation tool in metallography is the light optical microscope (LOM). Besides this tool, additional high resolution techniques like Scanning Electron Microscopy (SEM) or Transmission Electron Microscopy (TEM) have become increasingly important. With these and other available methods, extensive information on the microstructural state of a material can be gained. Unfortunately, most metallographic methods have a major loss of information systematically built in. Analyses of microstructures are usually performed on surfaces, i.e. on 2D areas that emerge by cutting through the 3D material structure. This means, a complete dimension of information is not taken into account. How serious this reduction of information is and how it can affect interpretation of structures is exemplarily demonstrated in figure 1, which displays the planar structure emerging from a random cut through a simple 3D structure. It is very difficult to deduce or even imagine the original spatial structure from which this projection emerged and it is impossible to reconstruct it with absolute certainty without further information. The image has emerged from a random cut through a 3D structure of stacked cubes that is displayed in figure 2. The area shown in figure I is outlined. Although artificially constructed, this example demonstrates how distorted and misleading the view on structures can become by ignoring a spatial dimension."

Jan 1, 2012

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 W. A. Thomas

STEAM is, and doubtless always will be, the basic power in the anthracite industry, either directly applied through engines and pumps or electrically. The rapidity with which electric power is being applied to the mining and preparation of anthracite leaves little doubt as to its utility and economy. There is practically no operation, except possibly the drilling of hard rock, that has not been successfully electrified and the matter of drilling is handled economically with electrically driven compressors and the standard compressed-air drills. Conservation and the seemingly ever-increasing cost of production, justify careful consideration of the possible results of the more extensive use of electric power in the industry. It is not planned to discuss, herein, the relative economies of individual applications but to consider the relative economy and flexibility of steam and electric power. The reports available for the year 1920 indicate a production of slightly over 80,000,000 tons of anthracite, of which 8,843,500 tons were used for power and heating purposes; in other words, over 11 per cent. of the production was used at the mines. Some of this was used to generate electric power at the mines, about 160,000,000 kw-hr., while 150,000,000 kw.-hr. was purchased from the public utility companies. One large producer, who is buying some electric power and generating some, used over 13 per cent. of the production for power and heating at the mines. Another producer, where considerable electric power is generated on the properties, is using less than 9 per cent. of the output for power and heating. One of the largest producers has a fuel consumption of over 15 per cent. of the output, besides which considerable power is purchased. A careful study of the field indicates that steam-operated plants use upwards of 13 per cent. of the production for power and heating, while electrically operated plants use about 1 per cent. for heating; so that, for steam-power purposes at least 12 per cent., or 268.8 lb., are used for power out of each ton produced.

Jan 9, 1921

By Julián Andrés Ortiz González

This work presents a series of experiments of Fatigue Crack Growth (FCG), which are intended to provide evidence about the main parameter controlling this phenomenon, whereas still no agreement about this, since the Paris´ theory is based on the principle that FCG is controlled by the ?K and the Elber´s theory says that the driving force is ?Keff. For the development of the experiments, some DC(T) specimens were machined with two different thicknesses: 2 and 30 mm to perform FCG tests in plane stress and plane strain state, respectively. Besides this, all FCG tests were carried out with a constant ?K e Kmax, measuring the strain with a Strain-Gage bonded on the back face of the specimen and seven Strain-Gages located on the crack growth path. The data needed to measure the crack opening load, and the ?Keff, were collected through a program developed in Labview. Finally, the data post-processing was carried out based on the ASTM standards and several articles of recognized authors in this field, in order to compare the two positions with the experimental data, and this way conclude which is the most consistent theory with the observed behavior.

Aug 16, 2017

By Bernard H. Hertlein

The introduction of LRFD methods for structural design has been a gradual process by AASHTO, ACI, AISC, ASCE, and the FHWA, which has largely been ignored by the deep foundations industry. In 2007, however, the industry has been obliged to embrace LRFD for any deep foundations on projects involving federal funds. The authors are concerned that the risks caused by the need for, and the difficulty of providing, reliable quality assurance, will result in unnecessarily high safety factors that will defeat part of the purpose of LRFD. A primary attraction of LRFD for owners and engineers alike is that it promises more efficient design, and therefore cost reductions. Unfortunately, a key element of LRFD philosophy is often overlooked - that the applied safety factors can be rationally reduced, often allowing less material to be used, thus saving costs, but only if all the risk factors involved are identified and closely controlled. This means that both the quality of the materials and the quality of the construction work must be adequately monitored, and held to an acceptable standard. In the case of deep foundations, the soil in which the foundation is constructed is also a critical component that must be taken into account in the assessment of risk factors.

Jan 1, 2007

By S. Hardcastle

Tele-remote operation of production equipment from surface will change the design criteria for underground mines. And for ventilation, with machine operators on surface, conventional planning to dilute and remove pollutants can become redundant. Natural Resources Canada with industrial partners are investigating what will be the new environmental design criteria. Additional complications include new mining equipment being designed without standard services and mines’ desire to eliminate conventional auxiliary ventilation. Findings to date show the cooling of equipment’s hydraulic systems to be the most demanding element, especially in dead-ends and when stationary. Consequently, revised ventilation based heat control strategies for equipment are being developed for the automated mine of the future.

Jan 1, 2001

By H. A. Pearse

NORMALLY, the Britannia ore mixture contains chalcopyrite and pyrite as the chief sulfide minerals, together with minor amounts of gold and silver and a low zinc content. Reduction is accomplished by jaw crushers underground, followed at the concentrating plant by Symons cone crushers, rolls, and ball mills. The standard flotation practice, evolved during several years of experimentation, provided for bulk flotation of the two sulfides, after primary grinding to only approximately 35 mesh, followed by regrinding of the bulk concentrate, with subsequent separation of the chalcopyrite and pyrite to make a marketable concentrate of each mineral. This so-called standard milling practice has previously been described in detail in U. S. Bureau of Mines Information Circular 6619. A modification will he discussed here. In the face of a constantly increasing world surplus of copper and a steadily falling price during 1930 and 1931, it was obviously undesirable to continue unprofitable production of large quantities of this metal. On the other hand, company officials were

Jan 1, 1934