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By Zhaohui Qiu, Yaguan Ji, Hong Zhong, Qingxia Liu, Yada Liu

"Water is a necessary process medium in mineral processing. For the operations where fresh water is not available, sea water could be used as an alternative processing medium to replace the fresh water if we would have built a solid understanding of the interfacial science and flotation chemistry of sulfide minerals in sea water. In this research, micro flotation of chalcopyrite and pyrite in deionized water and sea water were investigated. For chalcopyrite, the recovery starts to drop from pH 10 in deionized water and from pH 9 in sea water, and the flotation recovery close to 100% before it drops. We can found from the results that chalcopyrite flotation is depressed much at pH 11 in sea water when much white precipitate is found. For pyrite, the flotaion recovery changs a lot in deionized water with 1*10-5 M potasium amyl xanthate (PAX) as collector. It’s relatively high at pH 8~10 compared with that at pH<8 and pH>10. While in sea water, the trend is almost the same as that of chalcopyrite. Zeta potential measurements and chemical equilibrium calculation were used to find out that magnesium hydroxide species coats on the surfaces at high pH in sea water are the main reason for depressing the chalcopyrite and pyrite flotation. Through understanding the interfacial science and the solution chemistry of sea water and its impact on processing efficiency, this research will not only helps reduce the use of fresh water to minimize the disposal of spent water for environment protection, but also enhance the recovery of valuable minerals in froth flotation."

Jan 1, 2014

By Demetrius Da Rós Ruy

O lingotamento contínuo é uma das etapas mais importantes na produção de aço, sendo um método rápido e eficiente na fabricação de placas ou tarugos através de processos de resfriamento onde o aço líquido é moldado e solidificado. Contudo, têm sido historicamente observado problemas de processo corrosivo acentuado na câmara de exaustão e na estrutura das máquinas da ArcelorMittal Tubarão. Os mecanismos deste processo corrosivo em máquinas de lingotamento contínuo, em geral, são variados e diretamente relacionados às condições operacionais da máquina, conduzindo a elevados custos de manutenção, diminuição da vida útil das máquinas, causando insegurança e interferindo na qualidade do produto. Este trabalho objetiva descrever as causas principais deste processo corrosivo e mostrar o desenvolvimento de testes que foram conduzidos visando a minimização deste fenômeno na máquina de lingotamento de placas #1 da ArcelorMittal Tubarão no ano de 2017.

Oct 30, 2017

Geosynclines have been well studied for many years, but very little has been written about the concepts of sedimentary basins in spite of the vast amount of data available. They have been regarded, perhaps, as well- understood intuitively, and therefore not worthy of study. Many of the fundamental concepts of geology were developed during the 19th Century with the construction of coal mines, canals and railways. It was a happy chance that led railway engineers in the early days to think that trains could not climb any but the smallest gradient, so, in Britain at -least, numerous railway cuttings and tunnels were made. These exposed to view and study, in a better form than Nature usually provides, a great deal of interesting geology. Because of the lack of literature about the concepts of sedimentary basins, it is not possible to be sure what the early geologists thought. It seems that sedimentary basins were regarded as recording a history of subsidence during the early stages, when a transgressive sequence accumulated; and a history of uplift during the later stages, when a regressive sequence accumulated. It seemed axiomatic that the age of folding and faulting was younger than the rocks folded or Faulted.

Jan 1, 1987

By George A. Lamb

AMONG the main interesting developments in the coal market have been the changes that have taken place between the consumer groups. Important signs of these changes began to appear many years ago, but in a modest way, and were apparent only to the few fuel experts making broad statistical determinations. It is doubtful, however, that any of these experts appreciated the significance of their early findings, and perhaps none had the imagination to consider how extensive these changes might be eventually with respect to solid fuels sales and distribution. (Reference here will be principally to bituminous coal.) Railroad Fuel Major changes in coal use did become pronounced after World War II, and it did not take an expert to see what was taking place and how serious the impact was likely to be. First, was the case of the steam and diesel locomotives. The railroads had been considered the best coal customers; they were steady and large purchasers and usually paid a better price than most others. Railroad fuel provided the basic mine realization and it often was the source for operating cash during general market slumps. It was the outlet for 20 pct of the bituminous coal production, as much as 110 million tons in 1946.

Jan 2, 1957

By C. G. Dunn, J. L. Walter

COULOMB&apos; and Coulomb and Lacombe2,3 have recently discussed secondary recrystallization in soft iron (99.5 pct Fe). They found that the appearance of this phenomenon was dependent on both the presence of impurities and the thickness of sheet specimens. They concluded that impurities such as carbon, sulfur, and oxygen in the soft iron stabilized the matrix structure and allowed growth of a few grains of specific orientations. They also found that secondary recrystallization ceased when the final thickness was small and attributed this complete inhibition of growth in thin sheet to the restraining action of thermal grooves. When purer iron (99.99 pct Fe) was used, normal grain growth but not secondary recrystallization was obtained. On the other hand it is known that the necessary stabilization of the matrix structure for secondary recrystallization in high-purity silicon iron probably does not depend on impurities but more likely results from the specimen thickness effect of Beck et al.,4 according to evidence and ideas advanced by Walter and Dunn,5,6 and Detert.7 Furthermore, Mullins8 has indicated that if a gas-metal surface energy difference exists across a grain boundary equal to or greater than about 3 pct of the grain boundary energy, then such a grain boundary should not become stuck. Similarly, Walter and Dunn have estimated that any increase in restraining force due to increased thermal grooving with decrease in

Jan 1, 1962

Two independent sets of observations from rifted con-tinental margins suggest a way to reach a quantitative under-standing of how the topography of rifted margins erodes. First, a prominent erosional escarpment, which demarcates an elevated, inland region of low relief from rugged, deeply-incised terrain on the seaward side, is the main feature of the geomorphology of many rifted continental margins. Second, apatite fission track ages from the southeast Australian and southwest Saudi Arabian margins scatter about constant Paleozoic ages over the higher elevations inland from the escarpment, but decrease systematically seaward of the escarpment to near-rifting ages approaching the coastlines. We have developed erosion models based on conservation of mass principles to explain these observations. These models seek to explain the "rejuvenation" of erosion at the time of rifting, initiation of the observed erosional escarpment, and its migration inland with time at a rate on the order of 1 km/10 yr. We find from the modeling that erosion at rift flanks and passive margins is fundamentally a non-linear pro-cess. The erosional development of passive margin topogra-phy has much is common with travelling wave solutions to non-linear diffusion-type problems, and to self-similar sto-chastic processes, such as diffusion-limited aggregation. We suggest that the fission track data record the thermal effects of erosional unroofing at rift flanks and passive continental margins. Models intended to explain the erosional develop-ment of continental margins must explain both the geomor-phology and the fission track observations as well.

Jan 1, 1990

By Richardson G. W, Yap L. C

Friction rock stabilisers (FRS) are the most common steel-based ground reinforcement used in underground mines in Western Australia. As with any other steel-based product used in underground mines they are susceptible to corrosion, particularly under aggressive minewater and mineral conditions. Because of their thin-wall tubular construction and large surface area, the potential damage resulting from corrosion is considered to be more severe for this type of reinforcement than for other forms of reinforcement made of solid steel bars. Because of the obvious safety problems which may result from corrosion, both mine operators and regulators have raised concerns regarding the long-term effectiveness of FRS installed in underground mines in Western Australia. Although corrosion has been recognised as an important safety issue, the controls of corrosion in varied underground mining environments has not been well understood. To improve the understanding of the corrosion behaviour of FRS, the Department of Minerals and Energy has initiated a research project focused on the mechanisms and extent of corrosion attacks, and their influence on the effectiveness of the reinforcement. This paper describes the research project and presents the interim results achieved To-date.

Jan 1, 1995

By Irvin Lavine

THE discovery of several large deposits of natural sodium sulfate (Glauber salt) in the northwestern part of North Dakota during the summer of 1934 might have been anticipated from a knowledge of the topography and geology of this territory and from the presence of natural C A N A D A FIG. 1.-LOCATIONS OF GLAUBER SALT DEPOSITS, NORTHWESTERN NORTH DAKOTA. North Lake (deposit No. 7) is not shown on this map. It is approximately 13 miles north of Miller Lake (deposit No. 3). sodium sulfate deposits in western Canada, which have been known for several years. In the northwestern part of North Dakota is a chain of shallow lakes, which continues northward into Saskatchewan. Over twenty million tons of Glauber salt has been proved present in these North Dakota deposits. (See Fig. 1.)

Jan 1, 1936

By G. R. J. Cooper

In recent years attempts have been made to develop software packages for shallow seismic refraction data analysis. In most cases, mainframe computers were used which were generally non-interactive, did not support graphics and were unfriendly to operate. With these facts in mind, a user-friendly interactive processing package written in PASCAL has been developed for the IBM PC. The package allows the following operations to be performed. (1) data tying, equalisation of reciprocal and common shot times; (2) overburden velocity analysis; (3) refraction leg identification on time-distance plots; (4) elevation correction of refractor data; (5) forward and backward phantoming; refraction leg extrapolation; (6) &apos;bedrock&apos; velocity analysis; (7) &apos;time-depth&apos; plot computation; (8) depth calculation. Numbers (6) - (8) above involve Palmer&apos;s generalised reciprocal technique of refraction data interpretation. The program is extremely flexible and makes much use of interactive high resolution graphics and &apos;popup&apos; onscreen menus. The velocity analysis sections have statistical routines built in to provide error estimation. The programs allow data interpretation to take place in the field with a portable microcomputer while the data are still being collected; this is obviously not possible with any cumbersome mainframe-based software. Hence it becomes possible to see the effects of varying the data collection parameters (such as geophone spacing) upon the resulting interpretation and so enable adjustments to be made where necessary. Hard copies of the data may be obtained at all stages of the interpretation process using a small (A3) plotter, or the graphics may be dumped to a dot- matrix printer if a suitable plotter is not available.

Jan 1, 1987

By W. M. Shaver, R. Letourneau, W. R. Dengler

Dynatec Mining Limited contracted to sink a 1500 metre (4960 ft.) concrete lined shaft for Falconbridge Nickel Mines in Sudbury, Ontario, Canada. The shaft is 6.3 metres (20.5 ft) in diameter inside the concrete lining and is equipped with steel furnishings. Dynatec used the owner supplied 4.6 metre (15 ft.) diameter double-drum hoist to sink the shaft with 12.5 tonne buckets for muck removal and 4 cubic metre concrete buckets for concrete placement. One of the unique features of the shaft sinking operation is the use of a four-boom electric hydraulic drill jumbo permanently mounted in the shaft sinking stage. This paper will describe the performance obtained with the electric hydraulic drilling equipment and the high capacity muck removal and concreting equipment.

Jan 1, 1991

By Frank Haehnig

Ground freezing is a technique which is used more and more in tunnelling under complex ground conditions. This paper will present three case studies which highlight different aspects of the ground freezing technique when applied in urban environment. The first project is the City-Tunnel in Leipzig, Germany, which is being built beneath the central station and which is the largest ground freezing project currently under construction in Germany. The second case study is part of the North-South-Line project in Amsterdam, Netherlands where ground freezing will be carried out to al-low the TBM drive through old wooden foundation piles. The freeze tubes for this project will be driven using Horizontal Directional Drilling (HDD). The last project is the Hallandsas Tunnel Sweden where the ground freezing equipment has to be installed against high water pressure. The paper illustrates that ground freezing can be implemented in difficult ground conditions such as soft ground, highly fractured rock and high water pressure. The case studies highlight the importance of good workmanship. With the increasing numbers of large tunnels being constructed in difficult ground conditions the paper concludes that the complex case studies presented will be-come more representative for future tunnel projects in urban environments.

Jan 1, 2008

President MRS. THOMAS T. READ 9 Windmill Lane Scarsdale, N. T. First Vice-President MRS. FELIX E. WORMSER Acorn Lane Larchmout, N. T. Second Vice President MRS. W. SPROTT BOYD The Carlyle, Madison Ave. and 76th Street New York, N. Y. Third Vice-President MRS. LOREN W. KEMP El Chico, Plainfield Avenue Metuchen, N. J.

Jan 1, 1944

By Dr Subagyo

The energy consumption for producing metal from ore is strongly linked to the chemical stability of mineral being processed, availability and richness of the ore, and process route. Energy efficiencies are particularly linked to the process route. The energy efficiency of high temperature operations vary considerably but energy efficiencies greater than 70 per cent are achieved for large-scale metal production. Low temperature processing through grinding, leaching and subsequent electrowinning use large amounts of energy. In particular, grinding and electrowinning suffer from low overall energy efficiencies. The physical chemistry of a new proposed low temperature route, reactive ball milling, is unclear but preliminary evaluations indicate that it is likely to suffer from high energy consumption. In conclusion, low temperature processing routes for metals generally consume more energy that comparable high temperature processing routes.

Jan 1, 2002

By D. G. C. Robertson

Counter-current staged reactors offer several advantages over batch reactors for mass transfer between two phases. Several metallurgical reactor designs have utilized the counter-current principle, e.g. the WORCA and QSL processes. But before the principle can be widely adopted, it will be necessary to overcome several significant problems. These include the need to minimize longitudinal mixing in a single reactor or to use several separate staged reactors and to carry out different reactions in sequence, e.g. phosphorus oxidation and sulfur reduction. Theoretical and experimental approaches to these problems will be discussed in the paper.

Jan 1, 1988

By E. Y. Dougherty

Introduction As practised during the last two years at the Vipond Consolidated gold mine, mining geology has meant the application of geology to the problem of finding, developing, and mining ore. This article reviews the results attained in Vipond mining geology as thus defined. Most effort was directed toward clarifying and interpreting the tangible physical causes of vein and ore localizations, and in the following pages these questions are dealt with in considerable detail. Discernment of the influence of rock folding and deformation on the localization of veins, and of the influence of certain structures and rocks in or near carbonaceous zones on the localization of ore-bodies, have been the main practical results of the studies. Consideration of some of the geological features of the Porcupine area, and of the geology and mining experience of the principal producing mines, has helped toward a perspective of Vipond&apos;s ore-finding problems. These features are first discussed. The background and procedure for Vipond mining geology, and the major results of the geological mapping, are then summarized. Then follows a résumé of tangible factors that influenced vein, ore-body, and gold localizations; and, next, explanations of the facts ascertained. Because they were found of little utility, many fascinating problems, such as the origin and mode of emplacement of the veins and lodes(l), the ultimate source of the ore, and the physico-chemical and mechanical agencies affecting vein and ore formation, are treated cursorily or are neglected in these notes.

Jan 1, 1934

By I. Wigden

This paper discusses system integration and installation of High-Tec systems in underground mines. ABB has the capability to be a System Integrator and co-operates with partners in different areas of technology. Today it is difficult to find one Company that is responsible for the complete Automation System. The design of the system is also dependent on the caving procedure that is currently being used in mines. Most of the engineering must be done during the feasibility study and the design phase. Any mistakes made during these phases will be costly to rectify in the commissioning phase. The paper will also include a presentation of the benefit of using Automation in an Underground Mine, and the importance of integration with the people component. Most of the experience and discussions in this paper are from different technologies that have been developed in Scandinavia and adopted from LKAB in Kiruna. The author of this paper was responsible for the Automation projects in Kiruna Mine during1994 - 1999. These projects include: • Broadband communication of data, audio and compressed video in one data stream. • Control System for Haulage -1045m • Automation of Load Haulage and Dumping machines (LHD) • Control of Production Drilling Rigs from a Central Control Room.

Sep 1, 2001

The resource sector is conservative industry and people are resistant to change. The methods and procedures used to implement changes in process plants ultimately determine the success of such changes. The financial managers have a large say in where money is spent and the technical personnel must justify the cost and benefits for any expenditure. There are also others who believe it canÆt be done û æwe tried thatÆ. Implementing change needs a æChampionÆ who can assess the risks, plan, define the objectives and scope, set the goals, determine the key performance indicators (KPIs) and stay focused. This also requires preparing a budget and schedule and measuring against this. Contract management, reports and reviews are part of the implementation. Several case studies are given as examples of the implementation of process design changes to highlight the critical aspects involved.

Jan 1, 2009

By H. H. Einstein

Swelling ground is one of the most feared problems in tunneling. Although usually not causing sudden failures during construction, the very large and longlasting deformations give contractors and designers the impression of facing an inevitable phenomenon against which there is no technical defense. Examples are concrete liners up to 1 m (3 ft) thickness that have been cracked or crushed, tunnel inverts that are heaving at 0.1 m (0.3 ft) per week during construction and continue to heave during decades. This paper summarizes essential components of design construction procedures where tunnels in swelling rock can be built to perform satisfactorily. It is important to point out that design and construction cannot and should not be separated. The way the tunnel will be built has to be an integral part of the design. Swelling can be defined as time dependent volume increase and is distinguished from squeezing, another time dependent phenomenon occurring in tunneling. Squeezing involves exceeding the shearing resistance while swelling usually does not. Swelling of rock masses can occur as swelling of the intact rock, swelling of wall rock, of gouge and of filler in the discontinuities of a rock mass, and as a combination of the above. Swelling mechanisms have been discussed elsewhere (ISRM 1983).

Jan 1, 1984

By T Guiliani, F Ottuonye

Explosives casting is gaining increasing popularity as an overburden removal method in strip mining because the coats of using explosives to cast a percentage of the overburden to the spoil are lower than the costs of using stripping shovels or draglines to do all the overburden removal. This is due to the rising capital and operating costs of draglines and shovels.

Jan 1, 1989

By W. B. Mather

Literature dealing with rock drilling presents a mass of conflicting data. The principal cause of the confusion is attributed to varying definitions of the hardness factor of rock and cutting media. The future development of more efficient drilling methods demands that this problem be solved. The first step in the solution is the compilation of complete data on the physical properties of rocks.

Jan 2, 1951