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By Stavros H. Constantopoulos

Mediterranean regions such as Greece, Turkey, Cyprus, Corsica and New Caledonia have experienced epidemics of malignant mesothelioma as a result of non-occupational, ??domestic?? exposure to tremolite asbestos and fibrous erionite. This exposure to tremolite asbestos and fibrous erionite is typified ??domestic?? due to its prevalence in regions with natural deposits of tremolite asbestos (or fibrous erionite) where the material from tremolite asbestos or fibrous erionite is used for domestic applications such as whitewashing. However, these exposures may be useful in examining the potential consequences of even small amounts of amphibole asbestos fibers in the ambient air. It can also elucidate the effects of fibers that behave like amphibole asbestos. However, this type of exposure is not useful for studying the potential effects of small amounts of asbestos in the ambient air of big cities due to the differing nature of the fiber types and modes of exposure between the regions. © 2008 Published by Elsevier Inc. Keywords: Tremolite asbestos; Erionite; Domestic; Environmental; Exposure

Jan 1, 2007

By Mark M. Petersen

As part of the addition of eight new combined cycle generating units at the Florida Power & Light Sanford Plant, 2,129 piles were to be installed. The existing plant elements were supported on driven piles, and the variation in pile lengths during previous work, as well as available subsurface information, indicated a complex stratigraphy. At the request of the owner, the designer/construction manager developed a program to evaluate the use of pressure-grouted displacement piles. A pre-design load test program in areas that represented the apparent extremes in subsurface conditions indicated that the system was feasible; however, the presence of existing features that were to be demolished later precluded the clear delineation of subsurface conditions in advance of construction. A contract was negotiated with the pile installer based on the best estimate of potential pile lengths, with modifications to pile lengths to be set based on additional exploration. A total of 52 cone penetration soundings and five load tests were performed immediately prior to and during pile installation to establish correlations between the CPT data and pile performance. Pile depths were set based on these correlations. Pile installation was completed 6 weeks ahead of schedule and 15 percent under the original budget estimate. This paper documents the evaluation of pressure-grouted displacement piles as an emerging technology, and illustrates the benefits of a close working relationship between the owner, designer, and pile contractor at a site with variable subsurface conditions.

Jan 1, 2002

By T. J. Ballard

"INTRODUCTION The Buck. Creek corundum area of Clay County, North Carolina, includes one of the largest single masses of peridotite outcrops in the whole Appalachian Range and has been described by Pratt, an early authority on corundum, as offering one of the best potentialities for corundum production in North Carolina.Two principal types of corundum deposits are found at Buck Creek the vein type and the corundum-bearing amphibolite dikes.The vein deposits occur in structural fissures that strike north to northeast in a gangue of feldspar, zoisite, an, chlorite. The corundum is generally coarse-grained and good-quality. The corundum content varies from several percent to 50 percent.The corundum in the amphibolites is more or less disseminated through the dike, is generally lower-grade, and is less in quantity, than the vein corundum. About 50 percent of the amphibolite corundum is coarse enough for snagging-wheel grade but is difficult to separate from the amphibolite.Production from the Buck Creek area has been small and came mainly from high-grade pocket in the vein deposits. Pratt 3/ reports 300 tons of corundum ore was produced to about 1896. No record of subsequent production is available.The critical shortage of corundum during the war, due to transportation difficulties and the depletion of deposits abroad, prompted the Bureau of Mines to investigate domestic reserves.After a favorable report was obtained on the Buck Creek area, the Bureau began exploration of the deposit in September 1943 and continued until February 1945."

Apr 1, 1947

By Debbie Laney

DOUG HALBE: Second in our quick run-through on "Operating Ideas That Have Saved Me Some Bucks," was Debbie Laney of Rayrock Mines. Debbie apologizes. She can't be here. But she said, "Doug, don't worry. I've asked Mary Korpi to present the paper. We're both short, blond, and wear glasses. Nobody will know." [laughter] Mary, I caught it right away. You ladies can't fool us. Debbie, who wrote the paper, has spent almost her entire career in operations. She is currently metallurgical manager of Rayrock Mines in Valmy, Nevada. Mary Korpi is also a real operator (that doesn't sound right). She has been responsible for a number of operating areas at Newmont's Nevada operations, and she is currently taking a break from operations as manager of public relations/employee communications for Newmont Gold in Carlin. MARY KORPI: They told us this year at Newmont that we were going to have to work twice as hard. I had no idea it meant I would have to work for another company, too. Over the years, and many times in association with work for mid- to small-size mining companies, there have been two areas that seem to have been the focus of cost savings when looking at new facilities or new processes.

Jan 1, 1998

Performance of Outotec FloatForce« Flotation Mechanism - A Study in Both Computational Fluid Dynamics and Industrial Scale Measurement

Sep 13, 2010

For the purposes of this discussion it is assumed that contributors should express the thoughts that arise from their personal experience. So wide is the range of mineral deposits, and so varied the methods employed in their discovery and development, that no two geologists are likely to have been impressed with the same applications of their science. The author's own personal experience has been, during recent years at least, very largely concerned with the broader aspects of the employment of scientific method and geological knowledge to the problems of exploration and exploitation, for the guidance of the general public and governmental authority rather than of mine executives and directors. The view-point thus reached is likely to differ in many respects from that of men who are much more intimately concerned with the mining problems of a single metal or a single mining field, and for this reason a statement may perhaps supplement those from others whose experience has been markedly different.It may well happen that, at some not distant date in the future, when systematic and comprehensive instruction in economic geology is embodied in the courses- prescribed for mining engineers during their years of training, the author's comments will be quitesuperfluous; but at the present time they appear to him to call for expression.The Need for Training of Mining Men in Economic Geology.Contact over a period of many years with mining men who have had different kinds of training and experience has been convincing that there is a general reluctance to acquire a full rational understanding of the geological factors involved in exploratory and developmental problems. The correction of this attitude is regarded as vital to the industry and it is necessary to insist that the outstanding requirement of the present day is the utilization of all branches of geological, investigation in the field and the laboratoryby men who have had systematic and specialized training in these matters. The science of geology is many-sided, but is, nevertheless, whole and essentially indivisible. No one can afford to disregard any fraction of its content 'or any of its methods of investigation.The greatest advances have been made in the understarnding of the occurrence of mineral deposits by those whose knowledge Qfbasal principles, has been soundest, whose endeavour has been to ascertain all their relationships in space and time, whose attention to detail of all kinds has been keenest, and at the same time, whose capability to distinguish between major and minor features has been most marked.With the passage of the years and the accumulation of data from many lands, it has been possible to build up a great body of information regarding the primary deposition and secondary alteration of mineral occurrences, which is of the utmost value in guiding thesearch for new deposits to take the place of those that become exhausted. This heritage is due not only to the efforts of gifted in...

Jan 1, 1950

By Noris Costa

La posibilidad de construir presas hechas con los propios relaves que van a ser contenidos posteriormente, es una alternativa común en la minería. Sin embargo, durante el levantamiento histórico de estas estructuras, se identifican diversas rupturas, liberando las masas contenidas en las presas y contaminando el medio ambiente. En este sentido, el presente trabajo señala los geoindicadores como herramientas de monitoreo de presas de relaves -en tanto el estudio de estas características ha posibilitado discusiones al respecto de la seguridad de estas estructuras, así como propuestas de medidas de control.

Sep 9, 2007

Drilling and blasting are an essential part of most mining operations, and are commonly major operating cost centres. The effectiveness of blasting can have a significant influence on all subsequent activities, and hence overall operating costs. Drilling and blasting systems must be compatible with the overall mining method, to minimise total costs and ensure operational efficiency. Selection of suitable equipment and techniques requires an understanding of the total operation, plus current skills in specialised technologies. This paper examines the contribution of drilling and blasting to total costs, including the balance between capital and operating costs. The use of computer modelling is discussed, to demonstrate how blast performance and costs can be predicted and alternatives analysed. Case studies illustrate how cost savings can be made in operating mines, and alternative systems evaluated to optimise new projects.

Jan 1, 1990

By Valentín Pamo Caytano

La electrorefinación en un electrolito de CuSO4 - H2SO4 es usado universalmente para producir cobre de alta pureza a partir de los ánodos impuros. Aunque una parte de las impurezas se disuelve durante la electrorrefinación y se concentra en el electrolito, otros elementos son insolubles y se acumulan como lodos anódicos en las celdas de refinación. Las impurezas deben ser removidas del cobre para cumplir las especificaciones del mercado sobre la ductibilidad y conductividad y para recuperar los sub-productos valiosos como el oro y la plata. En ese sentido, el presente trabajo describe los equipos y procesos que permiten la recuperación del oro refinado en la planta de metales preciosos de la Refinaría de cobre de Ilo.

Sep 12, 2011

By G. W. Marks, A. H. Roberson

"Previous investigation 4/ has demonstrated that some of the aliphatic amines are suitable absorbents for 302, This paper reports the results of physical studies of a number of such amines with the object of determining which is most favorable as an absorbent.Monoethanol amine, diethylene triamine, and triethylene tetramine appear to be the most promising of all the amines studied, and most of this report has been devoted to studies of the physical properties of their aqueous solutions, which contain varying amounts of SO2.PURITY OF MATERIALSAll of the amines used were of commercial grade, because the primary object of this research was the investigation of a proposed works process rather than the accumulation of scientific data.The aminoethyl derivitives of ethylene diamine, namely, diethylene triamine, triethylene tetramine, and tetraethylene pentamine, only recently have been produced commercially. The chemistry of aliphatic amines is complex, and these newer derivitives have not been investigated, completely. Chemically pure material is not on the market, and since definite physical standards have not been published, one could not be assured of a pure product even if the commercial material was refined.The compilation of physical constants for the pure amines would involve much time—consuming effort without materially enhancing the value of this paper, as this work was not devoted to the development of fundamental standards."

Oct 1, 1938

By P. C. Holloway, A. Tshilombo, T. Xue, M. J. Collins, R. Lopetinsky, I. Mihaylov, I. M. Masters

The Voisey’s Bay deposit contains a trace amount of cadmium, which reports to solution during pressure leaching of the nickel concentrate at Vale’s Long Harbour Hydrometallurgy Plant, and must be removed to produce high quality nickel cathode. In 2006, Vale approached Sherritt Technologies to collaborate on the development of a process for removing cadmium to low levels (<1 mg/L) in the nickel raffinate. Following successful bench scale and pilot plant testing at Sherritt’s laboratories, the cadmium removal process was then moved through engineering and construction, culminating in the successful commissioning and startup of a cadmium removal circuit at the Long Harbour Hydrometallurgy Plant in 2017. This paper presents the results of this collaboration and the challenges that were encountered through each stage of development, as well as current results from operation of the commercial cadmium removal circuit. INTRODUCTION Vale’s Long Harbour Processing Plant, with a nameplate capacity of 50,000 t/y nickel, began operation in 2014. In addition to electrolytic nickel rounds, the plant also produces electrolytic cobalt rounds and copper cathode. The Long Harbour Processing Plant uses a unique hydrometallurgical process developed by Vale Base Metals Technology Centre, as shown in Figure 1, to treat a nickel sulphide concentrate produced at the Voisey’s Bay mine and mill located in northern Labrador (VBN concentrate) (Stevens et al., 2009).

Jan 1, 2019

By Terry L. Muldoon

The report describes the development of preliminary requirement specifications for standardized operating controls for roof bolting machines used in underground coal mining. According to recent statistics, roof bolting continues to be one of the most hazardous occupations in underground coal mining. The two principal hazards to the roof bolter operator are the machine itself and roof falls during the bolting cycle. The lack of standardization of machine controls is a major contributor to this hazardous situation. Observations of roof bolting operations and discussions with roof bolter manufacturers coupled with detailed analyses of roof bolter control design specifications were performed during this study. Detailed roof bolter operator task analyses, commonality of control analyses, and classical link analyses were also performed. The results of these analyses were then used to produce preliminary requirement specifications for standardized controls.

Jan 1, 1980

By Donald J. Hallbom

"While pipeline hydrotransport is often the most economical way to transport large volumes of mineral concentrate, tailings, or fine ore slurry over long distances, it is in mountainous terrain that pipelining becomes particularly attractive. These areas are often remote, with limited existing infrastructure and few potential users willing to share in the cost of new infrastructure. The rugged terrain makes the construction of railways or roads suitable for haul trucks difficult and expensive. The elevation difference between the mine and the terminal means that the empty trains or haul trucks need to return up-hill, resulting in high fuel costs. With pipelines, this elevation difference may reduce or even eliminate the need for pumping. As a result, numerous pipelines have been built, or are being considered, in mountainous regions around the world including: Tasmania, New Guinea, China, Madagascar, the Rockies of North America, and the Andes of South America. However, there are technical difficulties that need to be overcome in the design and operation of mountain pipelines that do not affect pipelines on more level terrain. This presentation reviews some of these difficulties and methods used to overcome them.INTRODUCTIONPipeline transport of solid-liquid slurry (“hydrotransport”) is an important and cost-effective means of transporting large volumes of solids over long distances, especially from a single supplier to a single user (e.g., a concentrator to a port, a concentrator to a tailings dam, or a coal mine to a power plant). Pipelines are generally found to be more economically attractive than alternate transportation methods (e.g. trucking, rail, conveyors, shipping, or some combination) over the life of a project (Aude et al. 1974).Hydrotransport systems have been built in a variety of terrains, but it is in mountainous regions that pipelining becomes particularly attractive. These regions are often remote and generally do not have existing transportation infrastructure (roads, railways, navigable rivers). There are few potential users (e.g., farmers, other mines, forestry companies, etc.) who may be willing to share in the cost of new infrastructure. The rugged terrain makes the construction and maintenance of railways or all weather roads suitable for large haul trucks difficult and expensive. Mines tend to be higher than the receiving terminal (e.g. a port). This means that the empty trains or haul trucks need to return up-hill, resulting in high fuel costs. With pipelines, this elevation difference may reduce or even eliminate the need for pumping. Pipelines are easier to construct than roads and railroads in these areas for several reasons, including:"

Jan 1, 2006

By G. van Hout, D. Rahal

Caving is a mass mining method that is normally applied to large, low grade orebodies because of its low production cost and high capacity. However, equipment breakdown and poor draw management can cause mining costs to exceed that of all other mining methods. One way to minimize the effect of disruptions in the mining cycle is to use Mixed Integer Linear Programming (MILP) for long-term scheduling. This paper describes a MILP goal program which has the dual objectives of minimizing deviation from the ideal draw profile while achieving a production target. Schedule optimization is performed using a life of mine approach in which all production periods are optimized simultaneously. The underlying assumption being that material mixing in the short-term (between monthly optimization cycles) has a minimal effect on the long-term state of the panel. Schedule optimization is carried out using six general constraint types to model and control production. The constraint types define: deviation from ideal practice, panel state, material flow conservation, production quality, material flow capacity and production control. These constraints define production targets and drive production toward the ideal profile while maintaining correct mining practice. Application of the model using production scheduling data for a De Beers kimberlite mine. It is shown how different production control constraints regulate production from individual drawpoints as well as recovery of the ideal panel profile by implementing an optimised draw schedule.

Jan 1, 2003

By Paul Eger

The use of wetlands to treat mine drainage has become increasingly common, particularly as more information is available on their operation and construction. However, the lifetime of each system is still, at best, an estimate. Treatment lifetime depends on the types of processes that provide the majority of the metal removal. Anaerobic systems (vertical flow systems) rely primarily on sulfate reducing bacteria, which reduce sulfate to sulfide and generate alkalinity. Metals can be precipitated as sulfides, and acidity is neutralized. These systems can remove over 90% of the metals and increase pH from around 4 to over 7. The bacteria will remain active as long as the system remains anaerobic and contains an adequate supply of sulfate and small chain organics. Although estimates of lifetime made on the total carbon in the system suggest that lifetime should exceed 20 years, data from field and laboratory studies show that the rate of sulfate reaction decreases with time, and that after several years rates decreased substantially. To maintain acceptable treatment, either additional organic material must be added or the total metal and acid load to the system would need to be reduced substantially. Aerobic systems (overland flow wetlands) can effectively remove metals from neutral mine drainage by reactions with organic material in the substrate. Over 90% of the copper and nickel have been removed in aerobic systems treating mine drainage in Minnesota. The primary removal processes in these systems include adsorption, ion exchange and complexation, which are finite; removal will cease unless new removal sites are generated. Two wetlands built in Minnesota have been successfully treating mine drainage for 12 years. At one of the wetlands, the annual production of new removal sites has been estimated to be equal to the annual metal input, and, as a result, metal removal should theoretically continue indefinitely.

Jan 1, 2005

By William Reisz

Over the years as surface mining operations have become more sophisticated, angle drilling has become a more popular blast design technique, especially in areas where overburden and stripping ratios have increased. Another method of blast design is the staggered pattern, which greatly improves explosives distribution within the blast. While both methods present some engineering challenges, this paper will discuss how the two methods can be combined to enhance fragmentation, improve cast percentage, drill production ratios and highwall control. A practical engineering approach will be presented as well as a discussion on the discipline required to maintain a quality blasting plan.

Jan 1, 2002

By Sam S. Taylor

The disposal of oil-field brines by injection into subsurface formations other than fresh-water-bearing strata is a positive method of eliminating the harmful effects of mineralized water on fresh-water supplies, vegetation, and aquatic and other animal life. The methods used most generally for the disposal of brines produced with oil are (1) impounding in evaporation ponds, (2) controlled diversion into surface streams, and (3) injection into subsurface formations. Various States recognize one or more of the methods as legally authorized procedure. As a general rule, impounding brine in ponds and solar evaporation have not been entirely successful, principally because of the large volumes handled; the porous nature of the soil, and the low rate of evaporation. Likewise, the diversion of brine into freshwater streams by controlled dilution has not proved satisfactory in some areas, especially in parts of Kansas and Oklahoma where the rainfall is relatively low, because it has been impossible to obtain enough fresh water for such dilution.

Jan 1, 1939

By B S. Utting, W J. Cowie

The alluvial gold industry of New Zealand is based on the placer deposits in Otago and on the West Coast. Production from these since discovery in the 1850s has been an estimated 480 t (15 Moz) of gold. Annual output has expanded continuously since 1980 and is expected to be over 2 t of gold for 1989. Following a historical review, the characteristics of typical operations, which use hydraulic excavators and mobile trommel units are discussed. Descriptions are then given of alluvial activities in Otago and on the West Coast.

Jan 1, 1990

By David Caiden, Geoffrey Fosbrook, Jaidev Sankar, Donald Phillips, Jon Hurt, Anil Parikh

This paper will cover the progress being made on Phase 1 of New York’s Second Avenue Subway line. It will include a description of construction progress on the first contract to be let, which consists of a 248 m (815 ft) long launch box, 3.9 km(2.4 miles) of TBM tunnels and a tunnel sump; the packaging strategy for the remaining work; and the progress through Final Design of the remaining packages, including the two large span rock cavern stations.

Jan 1, 2007

In this address I look back over the past 40 years of mineral exploration in New Zealand û essentially the period since the Second World War (ie since 1945). It was the period of my personal involvement, and indeed of the personal involvement of a number of you. Luckily it was aperiod of great interest and activity. In the previous 50 years, virtually nothing had happened, and it is kindest to draw a veil over that period. In the very important earlier 40 years (1855 - 1895) the New Zealand gold rush occurred. That must have been a fascinating, rewarding period, which has been thoroughly documented by better historians than myself. I will simply comment firstly that its mineral explorers (gold-prospectors) were very successful indeed, and found most localities of the minerals they sought, in spite of using very different methods from ours of today. Secondly, they were preceeded by one of Maori exploration, which searched for a much restricted list of minerals, but succeeded in finding virtually every locality we know of today. The explorers of both of these early periods were obviously highly successful, but, in the time available, I must restrict myself to the period since 1945. I am currently editing the effective up-dating of Gordon WilliamsÆ &apos;Economic Geology of New Zealand&apos; (1974). It covers the last 12 years or so. Many of you are contributing to that volume û both as authors and as referees û and I would like to take this opportunity of thanking you all. Although this new volume excludes the energy field, many of us have been involved in it, and I am therefore including energy minerals in this review, as Williams did in 1974.

Jan 1, 1987