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By R. Frank Chiappetta, E. B. Wilson

"The maintenance records for AL-60 airlegs at Falconbridge Ltd. are used to demonstrate some of the procedures for the analysis of such data.The data are not representative of pure failure s of one type or another. In fact, the records are for the undefined pseudo-failures which are usually found in industrial operations. However, because the machines are brought to the shop only when inoperative, the individual recorded components are treated as failures. Manual calculations are conducted to show the analysis of variance (ANO VA) approach to determine whether certain data can be combined; only a limited number of the 206 machines being considered. The manual procedures continue with the weighting of the suspensions; i.e. terminations f or reasons other than the failure of the given component. After the data are sequenced in the proper order, the nature or pattern of the data is determined using the Kolmogorov-Smirnov (KS) test.It is recognized that these manual examples must be replaced by compute r methods 10 process voluminous data of this nature. Such programs are developed and available. However, a program called RELCODE is used in this case to correspond to the manual examples and to take into account the suspensions. These analytical procedures form the basis for those studies required for good maintenance management."

Jan 1, 1985

By Don McColman

"Tires, although not always the largest single cost item in open-pit mining operations, will place in the top three, along with explosives and fuel. How this high-cost supply is controlled is dependent upon on an efficient tire program. The success of this program is, in turn, dependent upon the people who are directly associated with tires and their use, namely: the mine's tire personnel, the tire sales representatives and a technician for the rubber company. The technician will relay his observations and information received from the mine personnel back to the manufacturer with recommendations to overcome current problems .Haulage truck tire life and costs in a hard rock open-pit mine are governed and controlled by four important factors:I) Field control.2) Operating within manufacturer's guidelines.3) Different tire purchasing methods.4) Scrap piles.Field ControlPerhaps the most influential people involved in this program are those who live with the tire through every hour of its lifespan: the truck driver, the shovel operator, the dozer operator, the grader operator and the shift boss. Of these, the truck driver has the most control, in that he can drive over or around rock s as these situations arise. The loading area, the edge of the haul road and the dump account for most of the tire injuries.This is why shovel, dozer and grader operators must appreciate their influence on haulage tire life. Spillage cleanup must be ongoing and is not being done adequately if any of these operators are idle. The shift boss that drives by a rock on the road without removing it or calling for a cleanup has little recourse with the truck driver who runs over it-he has sanctioned the driver's actions by his own neglect."

Jan 1, 1986

By Gabriel G. Walton

Conventional numerical modelling tools for analyses of underground excavations are well suited for modelling elastic behaviour and yield response of geomaterials with very simple constitutive behaviour. Non-dilatant elastic and perfectly plastic behaviour is most commonly used for preliminary analyses in the absence of the data required to consider more complex behaviours such as strainweakening and dilation. For truly brittle models, this deficiency is more acute. Current state of practice allows only for reliable estimation of the volume of failure, but not for any prediction of displacement. In fact, there is no consensus in rock engineering regarding the most accurate approach or most suitable tool to model the magnitude of the plastic deformation that strain-weakening or brittle rocks experience at tunnel boundaries, particularly when support is incorporated into these models. This problem is largely a function of a poor understanding of how inelastic dilation occurs in different types of rockmasses, the rate controls on strength loss and volume change during yield, and the complexities of rock-support interaction in yielding conditions.

Jun 1, 2012

"The gravimetric dust sampler is one of the tools now available to the industrial hygienists for determining the worker 's exposure to the numerous types of particulate matter that may be present in the workplace. The paper ' reviews the different sampling trains that can be used for the two major criteria for respirable dust and some of the sources of error in this dust assessment technique.IntroductionIt may be stated simply that the measurement of airborne dust in the working environment is done for one or two reasons: namely, for engineering control purposes and! or to evaluate the potential for toxicological insult arising from the inhalation of dust particles.This paper reviews the progress made in the development of dust-assessing instruments, particularly the gravimetric types designed to meet British and U.S. dust criteria , and discusses the limitations in their use for this purpose."

Jan 1, 1981

By K. Niboucha, M. Zergoug, S. Brick-Chaouch, H. Houali

"Corrosion is an electrochemical process that causes degradation and deterioration of various steel works (pipelines, drains, cisterns) whether they are buried, immersed, or not. Worldwide, we estimate that corrosion destroys a quarter of the annual production of steel at a rate of 5 tons per second. Several techniques are used to protect against corrosion. Among these processes, Cathodic protection, which is regarded as the best technique to assure the protection of steel, works against this phenomenon. This is achieved either by a system of reactive anodes, or by the technique of impressed current protection or other techniques. Before any installation of cathodic protection, a preliminary study and pre-evaluation of certain parameters must be made. In the present work, we will present an example of dimensioning of an installation of cathodic protection by imposed current of a pipeline using solar energy, where we discuss the following items:•,Evolutions of the potential as well as current along the pipeline and their respective expressions deduced from the laws known as telegraphists;•,Range of protection (potential of protection along the pipeline);•,Influence of the isolation resistance of the coating on the range of protection;•,Effect of the aging of the coating and its influence on the current of protection."

Jan 1, 2005

By A. Gutiérrez

At present, most ore milling is done in tumbling mills, consisting of huge cylinders turning on their horizontal axis. This rotational motion causes the ore charge and the grinding balls to interact by impact, compression and abrasion, to reduce the size of the ore. This method is very inefficient since only around 12% of the energy supplied is used for actual grinding, the rest being used in moving the large mass of balls and ore within the mill. This work aimed at better understanding the milling process by evaluating the movement of the load through the Discrete Elements Method (DEM). First, the number of bodies (balls and ore) moving inside the mill is determined, to correlate to the potential impacts that constitute one of the milling mechanisms. Then, the number of high energy impacts is evaluated to correlate to the bodies in motion. At this stage, a differentiation between grinding media and the ore, as well as between the types of contact taking place in the mill, has to be made. This latter issue is of great relevance since from the five identified contact types (ball-ball, ball-liner, ore-ore, ball-ore and ore-liner) only the last three actually contribute to the milling process, the other two causing structural damage to the mill.

Jan 1, 2007

By Janne Karonen, Stephen Hughes, Mikael Jåfs, Jan Stål, Hannu Johto

End-of-life electrical and electronic scrap material attracts attention as a good opportunity for new value creation through efficient metal and energy recovery of such materials. On the other hand, the treatment of such wastes becomes important to avoid problems for society and environment. Treatment of such secondary raw materials faces multiple challenges due to their increasing complexity and evolving nature. Processing of these complex scrap materials together with recovery of a wide range of valuable metals with a combination of pyrometallurgy and hydrometallurgy using Outotec technology is discussed in this paper. One key consideration is environmental performance which needs attention when processing such complex secondary E-waste materials. Outotec has successful experience with commercial projects in the countries at the forefront of environmental and operational standards. INTRODUCTION Increasing attention has been drawn to the responsible processing of end of life Waste Electrical and Electronic Equipment (WEEE) as part of metals recycling, especially copper. It has been estimated that the amount of WEEE globally in 2016 was around the level of 46 Mtpa (Balde et al., 2017), representing a major disposal challenge but at the same time huge opportunity for resource recovery. The potential for increasing the recovery is high, because the official recycling rate of WEEE is in 2016 only 20% (Balde et al., 2017) and at the same time the estimated increase of the WEEE amount is between 3 and 5% per annum in the EU (Eurostat, 2019).

Jan 1, 2019

By J. F. Magee

THERE is nothing new about drag-line dredging for placer gold. The use of the separate unit for excavating preceded the large barge with bucket-line excavator mounted upon it, which has developed to a high state of perfection through use in every part of the world. But at present there is a vogue for a small, inexpensive plant to work economically the shallower gold gravel deposits that the bucket-line dredges do not work. The dragline dredge consists of the drag-line excavator, on caterpillar mounting on the edge of the dredging pond, which feeds the gravel to the washing plant, mounted on a floating barge in the pond. There have been more than twenty-five such plants built and operated in central and northern California and an unknown number in other States. There have been variations in details of design but the essentials are similar in all. I wish to describe the operation of a typical drag-line dredging plant, that of the Wyandotte Gold Dredging Company on the Farnan Ranch in the Oroville district. This organization of six active partners built their first plant on Wyandotte creek in the autumn of 1933. The operation was successful due to wise management, which was based upon good plant design and proper principles of operation. The partners elected one of their number, H. F. England, as manager with full control and responsibility. This plant and operation furnished the pattern for many subsequent ones.

Jan 1, 1937

By Cheng-Ting Chiang

Information integration and exchange for the entire building life cycle is one of the most important issues in the AEC industry. Although the Building Information Model (BIM) technology is widely utilized to address them, BIM is mainly concerned within the design and construction (D&C) phases. In the operation and maintenance (O&M) phases, however, the information integration and exchange issue becomes more complicated because software applications here require not only BIM but other information outside of the AEC domain, e.g., disaster mitigation. Nowadays, most BIM-related research focuses on the D&C phases and pays less concern on the O&M phases, hence there is a research need that can help seamlessly transfer the information between the D&C and O&M phases. In this research, a software framework using ontology was designed to deal with aforementioned problems. The BIM data from the D&C phases were used as a foundation to generate new models for different software applications for the O&M phases. The ontology technique was employed to assist the model transformation process between the original BIM and the models for applications. Finally, a disaster mitigation example was chosen to validate the framework, in order to make sure that the transformation process is comprehensive and useful from domain experts? perspective.

Aug 1, 2013

By So-Yeong Lee, Moosang Lee, Seung Hwan Ahn, Ho-Sang Sohn, Jongshin Chang

It is necessary to understand the characteristics, phase changes and chemical reactions of flue dusts introduced from a furnace to an off-gas line in order to achieve the stable operation and the improvement. This study is to develop the dust reaction model for chemical reactions of dusts in an uptake shaft of smelting furnace and a waste heat boiler. Phase equilibria and reaction paths in this system were determined by thermodynamic calculation with experimental and industrial data. The oxidation reaction rate of dusts was determined by the gas film mass transfer controlling. And the sulfation reaction rate was evaluated by the unreacted shrinking core model. Kinetic parameters were estimated by reference data including industrial ones. The present study with the developed model shows various effects of temperatures, dust particle sizes, and O2 gas partial pressures on dust reactions. INTRODUCTION The flue dusts from a copper smelting furnace move along a furnace off-gas stream into an uptake shaft and a waste heat boiler (WHB) and electrostatic precipitator(s). It is necessary to control the dust quality in order to stabilize the operation because the sticking behaviors differ depending on the phase of dusts. Phase changes of dusts are caused by chemical reactions at given conditions such as temperature and partial pressure of gases. Therefore, it is required to understand the phase changes and chemical reactions of dusts in order to perform the improvement and stable operation. The present study carried out the investigation to understand their fundamental knowledge. Especially, this study was focused on the kinetics of chemical reactions of flue dusts, developed the model. In particular, the scope of development and utilization of the model was defined as the uptake shaft of the Mitsubishi S furnace and the S-WHB radiation section in the Onsan smelter. Information needed for the modeling work referred to data from these processes.

Jan 1, 2019

By Charles S. Ney

"THE WRITER'S acquaintance with Kootenay King mine is limited to a brief geological excursion in the vicinity. This paper has been compiled largely from maps of J. Sullivan, mine geologist in 1952, kindly made available to the writer by Transcontinental Resources; a 1942 private report by W. L. Brown; and personal communications with J. Sullivan. Remarks on regional geology, and the comparison with Sullivan mine, are specifically the writer's.The Kootenay King mine is situated in the westernmost range of the southern Canadian Rockies at an elevation of 7,300 feet. From the Sullivan Mine at Kimberley, B. C., it lies 19 miles due east. Six miles of this distance are represented by the pronounced topographical and structural gap of the Rocky Mountain Trench. Mineral claims were locat-ed in the area prior to 1898. The deposit was first seriously explored in the late 1920s, and a small orebody was then outlined and developed. Mining and milling were undertaken in 1951.52. The orebody, amounting to about 14,000 tons, was mined out, and no significant new ore was revealed.The orebody is a replacement of dolomitic argillite by fine-grained galena, sphalerite, and pyrite. The sulphides are finely laminated in the direction of bedding, following out minor folds faithfully. The grade of ore estimated from diamond drill holes (W. L. Brown, 1942) was 11 ·I per cent zinc, 11 ·I per cent lead, and 3·8 ounces per ton of silver. The mineralized zone extends about 250 feet horizontally, 160 feet vertically, with a width of six to twenty feet.General GeologyThe country rocks are sediments of the Aldridge formation of late Precambrian age. For several thousand feet stratigraphically above and below the mine, the formation consists mainly of thinly laminated argillite and siltstone. Several horizons contain appreciable carbonate. About 2,800 feet stratigraphically below the mine, predominantly dolomitic beds mark the top of the underlying Fort Steele formation. The medium-bedded fine quartzites, which characterize about 10,000 feet of the Middle Aldridge in the Purcell range, have a restricted development amounting to only 2,000 feet in the Rocky Mountains. This member is about 2,200 feet above the mine horizon."

Jan 1, 1949

By Frank Baczek, R. Q. Honaker, D. P. Patil, B. K. Parekh

Fine refuse slurry impoundment is a requirement for the coal industry to dispose the fines. Impoundment maintenance is an on going problem for the coal industry and its breakage creates environmental as well as financial problems. Deep Cone thickener technology which has been successfully applied in the alumina industry to dewater red mud was evaluated for fine refuse slurry. Preliminary obtained in a pilot-plant test showed that properly flocculated conventional thickener underflow slurry could be thickened to about 52.5 wt % solids and could replace belt filter press. The Deep Cone thickener was also found to dewater clean coal slurry to about 70 wt % solids. Further testing of the unit at other coal preparation plant is in progress.

Jan 1, 2004

By A. A. Abdul-Latif, A. Sahin

"The phosphate deposit, located in the Abu Tartur plateau between the Kharga and the Dakhla Oases in the southern part of the Western Desert of Egypt, is the largest of its kind in the country. The phosphates are found in two horizons referred to as the Lower and Upper Phosphate Horizons within the Late Campanian Sibaiya Formation which belongs to the Nubia Group.This paper presents the results of a geostatistical study on the main phosphorite bed at the base of the Lower Phosphate Horizon which contains almost all the commercial reserves in the area. After semivariogram modeling for the phosphate thickness and accumulation, ordinary block kriging was employed to estimate the values of these variables in blocks of400 m by 400 m dimensions. The kriging results, which are presented in the form of contour maps, can be of considerable use in both future exploration and exploitation of the deposit. The grade-tonnage relationship based on the grade estimates derived from the corresponding thickness and accumulation estimates indicates the existence of 453.9 x 105 tonnes of phosphate above a cut-off grade of 18% P2O5. The mean grade of this tonnage has been estimated to be 25.77% P205"

Jan 1, 1990

By J. H. Hodgson

"Those of us who have been concerned with the problem of geophysical exploration in southwestern Ontario have followed the development of the Poulter method with much interest. I have much appreciated the opportunity of reading an advance copy of Dr. Poulter's clear exposition and of preparing the following brief remarks on the probable applicability of the method to the Palaeozoic area of southwestern Ontario.During the years 1944 to 1946, the Ontario Department of Mines, in co-operation with the Union Gas Company and the Dominion Natural Gas Company, operated an experimental party in the hope of establishing a seismic technique appropriate to the •area. The results were completely negative. During two summers' field work, no reflections whatever were obtained except in one area near Windsor. It is the •purpose of these remarks to inquire whether Dr. Poulter's techniques might yield favourable results.It was the conclusion of the report on our work that two principal causes contributed to the failure of the method. In the first place, the geological column possesses few elastic discontinuities and those that exist appear to have low reflection coefficients. In the second place, the area is drift-covered in general. This drift complicates the situation by absorbing seismic energy and by giving rise to groups of complicating refracted phases which obscure the entire interesting section of the record. The situation is further complicated by the high reflection velocities and the relative shortness of the Palaeozoic section, these factors combining to bring in a reflection from the basement in about half a second."

Jan 1, 1950

By B. P. Verma, K. N. Sinha, N. M. Raju, B. Singh

The paper describes a new method of grouting bolts developed at the Central Mining Research Station at Dhanbad in India. This method makes use of wire-mesh sleeve instead of the expensive metal tube to insert the cement mortar into the drill hole. The field trials confirmed that the method is cheap and an effective system of support.

Jan 1, 1972

By M. Sokoto, H. Hata, K. Nishina, K. Haiki

Fluoride ions in zinc electrolyte cause corrosion to aluminum cathode plates at zinc electrowinning process, so we have developed an iron compound as a fluoride ion adsorbent used in zinc sulfate solution. The iron compound is synthesized from FeC13 solution with a small amount of sulfate ion by neutralizing reaction with Na2CO3 solution. The fluoride ions adsorbed on the surface of the iron compound are desorbed in alkaline solution and the iron compound can be reuse as a fluoride ion adsorbent. Moreover, if adsorption capacity of the iron compound decreases, it can be dissolved in HCl solution and re-synthesized.

Jan 1, 2008

By G. R. Guillet

Salt is restricted to five major beds in south western Ontario, totalling as much as 200 m in thickness. These beds are located at depths ranging from 270 m to 750 m below the surface, fringing Lake Huron and the Detroit River from Windsor to Kincardine, and extending inland as far as London. Manitoulin Island, the Bruce Peninsula and the north part of the Niagara Escarpment form the northeastern rim of the Michigan Basin, a major structural depression in which the salt was deposited 400 million years ago when much of North America was covered by the Silurian sea. Salt is mined underground at Windsor and Goderich; it is also brought to surface as brine through deep wells at Windsor, Samia and Goderich. Artificially- created caverns in salt beds are extensively used for storage of liquid hydrocarbons at Windsor and Samia.

Jan 1, 1984

By Roger M. Nendick

"IntroductionThe stages of development for bringing a mill into production demand that a flowsheet for the process be developed at an early stage. Detailed engineering of the mill may then proceed without duplication of engineering effort on alternative processes. In the case of gold and silver mills, several process alternatives exist which must be evaluated before the flowsheet is finally fixed. The recently developed Carbon-in-Pulp process has added to this choice.Clearly, the major factor in determining the most suitable process is the amenability of the particular ore to a given treatment. Other factors that will also influence the choice are location, climate, power and water supplies, and available capital.Gold and silver milling processes can be divided into three main types:Gravity Concentration;Flotation;Cyanidation.Combinations of the three are frequently used; i.e. flotation followed by cyanidation of the concentrate, or gravity concentration in the grinding circuit with cyanidation of the classifier overflow. The following are the salient advantages and disadvantages of the three main alternatives.Gravity ConcentrationGravity concentration is suitable for free-milling gold ores, i.e. ores in which the gold is relatively coarse and free from sulphides. It should be noted that just because an ore is high grade, it is not necessarily free milling.Gravity concentration methods include jigs, shaking tables, spirals and more recently Reichert cone concentrators. All methods exploit the density difference between gold, which has a specific gravity greater than 15, depending on how it is alloyed, and the gangue, which usually has a specific gravity range of 2.7 to 3.5.A concentrate grade of several hundred ounces per ton might be produced, but recoveries by gravity alone are generally low in comparison to other methods. For this reason, gravity circuits are usually used in combination with flotation or cyanidation circuits."

Jan 1, 1983

By K. M. Wild, C. D. Martin, F. Amann

Peak laboratory strength data obtained from low permeability clay shales/rocks often display a bilinear or non-linear failure envelope. In many of these tests pore pressures are not measured because of issues associated with back-saturation prior to confined compressive loading. In such tests the effective state of stress at failure remains unknown and provides room for speculation. The non-linear shape of the failure envelope may have several reasons including the influence of capillary forces or the tendency of a saturated clay shale to dilate as the confining stress is changed. The former stems from sample preservation, preparation or core unloading effects and represents a partly saturated state (i.e., not representative for the in-situ state); the latter represents the response of a saturated material. This contribution discusses these issues based on a data set obtained from Opalinus Clay specimens, and concludes that without a careful back-saturation processes knowledge of the underpinning reasons for the non-linear failure envelope cannot be obtained.

Jan 1, 2015

By Desmond M. Levins

"Australia has almost twenty per cent of the Western World's low-cost uranium reserves, located mostly in the Alligator Rivers region of the Northern Territory. At present, only one uranium mill is operating in Australia, but a number of new mills are planned for the early 1980s.Details are given of Australian uranium mining and milling proposals and the measures taken to minimize their environmental impact. Major factors affecting environmental impact are discussed, including treatment of liquid wastes, water management, control of radon and other airborne releases, and disposal of tailings. IntroductionAustralia is entering a new phase in uranium mining and milling activity . In the first phase of operations, between 1954 and 1971, about 10,000 tonnes of yellowcake was produced at five locations. Most of the production came from the mines at Rum Jungle in the Northern Territory and Mary Kathleen in Queensland. In the 1960s, the demand for uranium slumped, and much of the yellowcake produced at Rum Jungle was stockpiled by the Australian Atomic Energy Commission. The early uranium processing operations in Australia were typical of overseas practice at that time. Environmental problems were generally given low priority and pollution control measures were unacceptable by today's standards. There was little or no recycling of process water, acid waste streams were not neutralized and tailings dams were poorly designed. At Rum Jungle, oxidation of sulphides in waste heaps, tailings dumps and ore stockpiles subsequently led to destruction of vegetation and heavy metal pollution in a nearby river.In the early 1970s, major uranium deposits were discovered in the Alligator Rivers region of the Northern Territory. Significant orebodies were also located in the Great Artesian Basin in South Australia, in calcrete formations in Western Australia and at several locations in Northern Queensland. According to latest available estimates. Australia has about 160/0 of the Western World's uranium recoverable below $US 80 per kg U. Mining these orebodies will require pollution control measures more stringent than practised previously in Australia."

Jan 1, 1980