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By P. E. McKinney

Developments in engineering during the past decade, particularly as applied to marine construction, mining machinery and other purposes in which corrosion offers a serious problem, have created a large demand for a non-ferrous metal highly resistant to corrosion and at the same time useful in general construction work as a substitute for steel without materially decreasing the factor of safety or increasing the weight of the various parts over that ordinarily used in the case of mild steel. To obtain the combination of desired properties many compositions have been proposed and used with excellent success, but at the present time probably the most popular and most widely used combination is the non-ferrous alloy commonly called manganese bronze. This is nothing more than a high brass to which have been added, by the proper method of alloying, comparatively small percentages of aluminum, iron, or manganese with the definite purpose in view of strengthening the alloy and rendering it more dense and close-grained than the average yellow-brass casting. In the manufacture of manganese bronze a great deal has been said about the importance of using only the highest grades of raw material and the beneficial or detrimental effects, as the case may be, of various impurities, as well as the importance of adding the ingredients according to various formulas proposed; but in most of these cases the literature on the subject has dealt principally with the manufacture of this alloy from virgin metals and raw materials of the highest purity. It is the purpose of this paper to deal particularly with the possibilities that lie in the proper development of methods for manufacturing such an alloy by more economical methods than those which have usually been discussed in other literature on the subject. Shortages have recently existed in raw materials needed for many products entering into the various branches of engineering work, particularly the non-ferrous metals, and during the next few years of reconstruction the country will be flooded with many

Jan 1, 1919

By Suleyman Tekeli, Serdar Salman, Bulent Aktas

"The effect of La2O3 content up to 15 wt% on phase stability, sintering and microstructure of cubic zirconia (8YSZ) was investigated. XRD results showed that the specimens containing up to 15 wt% La2O3 were composed of only cubic structure. Also, the specimens doped up to 5 wt% La2O3 revealed no La2O3 peaks, indicating that La2O3 was completely solubilized in the cubic structure. However, when> 5 wt% La2O3 was added, the peak of La2Zr2O7 compound emerged, showing that the overdoped La2O3 was not solubilized in the 8YSZ matrix. The lattice parameter of the 8YSZ slightly decreased with the increasing La2O3 content up to 1 wt% but further increase in the La203 amount resulted in an increased lattice parameter. The comparison of grain size of the 8YSZ specimens with various La2O3 content showed that grain size slightly increased with the increasing La2O3 content up to 1 wt% but further increase in the La2O3 amount resulted in a decreased grain size.IntroductionAt atmospheric pressures, three polymorphic forms of Zr02 are stable at different temperatures i.e. monoclinic, tetragonal and cubic. A high-pressure orthorhombic form of Zr02 has also been reported[l]. The successful production of pure Zr02 bodies is not possible all the time due to the large volume expansion associated with the martensitic tetragonal-monoclinic transformation. This fact restricts the applications of zirconia, in spite of its excellent mechanical and thermal properties. However, the stabilization of the high temperature polymorphs at room temperature as stable phases is made possible by addition of suitable dopants. Fully stabilized cubic Zr02 and partially stabilized tetragonal Zr02 show interesting properties and are widely used as ionic conductors, coatings and gas sensors in solid oxide fuel cells and structural applications[2]. Most frequently used dopants include Y203, CaO, MgO and Ce02, although other oxides, such as those of rare earth elements, can also act as stabilizers of the high temperature structures. The incorporation of aliovalent cations to the lattice, forming substitutional solid solutions, allows to control the concentration of anionic vacancies in the structure. This aspect is particularly important in designing ionic conductors[3], and is also determinant in the stabilization process[ 4]. The process of stabilization with larger ionic radii dopants is rationalized by the crystal chemistry model[ 5], that describes the dopant cations as typical stabilizer when they have larger ionic size, lower charged state and higher ionicity than Zr4+ The ionic radius of Zr4+ is 0.84 Å and that for La3+ is 1.016 Å [6]."

Jan 1, 2012

By Trung Nguyen

Midwest is a unique uranium deposit with exceptionally high arsenic content. The ore body is located 17km west of the McClean Lake operation. The McClean Lake mill will be modified to process Midwest ore and handle solid wastes coming from the Midwest water treatment plant. This paper describes the modifications required of the McClean Lake mill, process challenges associated with treatment of the arsenic, and the possibility of recovering nickel and cobalt as a by-product. It also reviews the complexity in the design of the Midwest water treatment facility which incorporates reverse osmosis technology with conventional physical-chemical water treatment.

Aug 1, 2010

By Adrian C. Dorenfeld, John T. Oleksy

John D. Maefadyen Subject paper unfortunately has some serious flaws negating the usefulness of the paper. The authors claim that sulfur is the major source of production problems in cement kilns. This is not the case. Sulfur is not a problem as long as the mole ratio of sulfur to alkali oxides is less than, or equal to, 1. This is attributed to the sulfur preferentially combining with the alkali oxides and not acting as a clogging agent due to the nature of the pre-heater vessels. Where the mole ratio exceeds 1, many methods are available to eliminate or reduce the clogging problems such as using the preheater bypass or a precalciner with up to 100% kiln gas bypass. In non-preheater kilns, the presence of sulfates is hardly ever a problem anyhow. Thus, the level of sulfur in the fuel and raw material that might cause problems is not a fixed amount, but is predictable. The purpose of the paper is to discuss the economics of conversion of kilns in the Indonesian and Phillippine cement industries from oil firing to coal firing. This economic analysis has very little to do with the sulfur levels. Thus, the section of the paper on sulfates is actually rather meaningless. The economic analysis is also rather meaningless because the authors have failed to follow accepted economic analysis procedures by including interest charges. They have fallen into the trap of confusing financing with economic evaluation. When the accepted methods of economic evaluation are used, the return on investment increases to about 35%. In conclusion, the paper is not a meaningful contribution, and sadly, quite erroneous.

Jan 11, 1982

By John D. MacFadyen

Subject paper unfortunately has some serious flaws negating the usefulness of the paper. The authors claim that sulfur is the major source of production problems in cement kilns. This is not the case. Sulfur is not a problem as long as the mole ratio of sulfur to alkali oxides is less than, or equal to, 1. This is attributed to the sulfur preferentially combining with the alkali oxides and not acting as a clogging agent due to the nature of the pre-heater vessels. Where the mole ratio exceeds 1, many methods are avail- able to eliminate or reduce the clogging problems such as using the preheater bypass or a precalciner with up to 100% kiln gas bypass. In non-preheater kilns, the presence of sulfates is hardly ever a problem anyhow. Thus, the level of sulfur in the fuel and raw material that might cause problems is not a fixed amount, but is predictable. The purpose of the paper is to discuss the economics of conversion of kilns in the Indonesian and Phillippine cement industries from oil firing to coal firing. This economic analysis has very little to do with the sulfur levels. Thus, the section of the paper on sulfates is actually rather meaningless. The economic analysis is also rather meaningless because the authors have failed to follow accepted economic analysis procedures by including interest charges. They have fallen into the trap of confusing financing with economic evaluation. When the accepted methods of economic evaluation are used, the return on investment increases to about 35%. In conclusion, the paper is not a meaningful contribution, and sadly, quite erroneous.

Jan 1, 1983

By R. Velkova, D. Bojinova

The objective of the present investigations is to establish the effect of the preliminary mechanical activation of phosphates on the degree of phosphorus extraction by bioconversion of Bulgarian and Tunisian phosphates using A. niger fungi and T: thiooxidans microorganisms. The influence of the phosphate concentrations, the type of the nutritive medium and the incubation times on the process of biological mobilization of the phosphates was studied. When the concentration of phosphates in the medium is twice as high, an equal and/or higher degree of phosphorus extraction can be achieved through the bioconversion of mechanically activated phosphates compared with non- activated phosphates under similar conditions. A maximum degree of 90+% phosphorus extraction in utilizable form was achieved at definite conditions.

Jan 1, 2002

By Frank Kitzinger, Jacques Nantel

Under special circumstances, electrical energy can successfully replace chemical ex­plosives for blasting rock. High pressure plasma can be generated in the confines of a drillhole, by a powerful electrical dis­charge. The energy level can be adjusted to replicate the effect of a high explosive. The main difference is the almost total ab­sence of gas generation with electric blast­ing. Once the rock fractures, the small amount of matter used for generating the plasma rapidly cools off and regains its former volume. High speed film studies clearly show, that the initial speed of blasted rock fragments is the greatest, no further gas propelled acceleration takes place .. Figure 1, shows a typical electric blast of an oversize boulder of quarzite in an open pit mine.

Jan 1, 1992

By K. G. Tan

Widely available silver and arsenic bearing concentrates can be smelted to produce a discardable slag, a base metal speiss, and a crude silver button which is easily separated from the other phases after solidification. This paper discusses the development of a novel process as an alternative to existing nitric acid leach methods for the production of high purity silver from the raw silver button. Direct electro-refining of the raw silver anode in a sulphate medium is integrated with downstream purification and recycling modules that are customized to allow efficient recovery of silver and saleable by­products. The test results, flowsheet alternatives and process details are presented and discussed in terms of overall technical feasibility, economical viability and environmental compliance considerations.

Jan 1, 1999

By Hans von Michaelis

This paper examines the process options available for treatment of "refractory" gold ores. As more and more of the easily leached oxidized gold ore zones are exhausted, the pressure is on to find more economical ways of treating refractory gold ore deposits. Historically, refractory ores were generally concentrated, e.g. to make a flotation concentrate that could be roasted. A major development is taking place in the USA in which ores from which gold cannot be concentrated well by flotation are being treated using whole ore oxidation processes prior to cyanidation. Refractory gold ore treatment processes are generally expensive to install and operate. Thus, for a refractory gold ore project to be economically viable, the grade must generally be higher than for free milling gold ores.

Jan 1, 1993

By Kathleen A. Altman, Kevin Hegerle

FMC Gold Company start.ea processing ore at their Paradise Peak Mine in 1986. Gold, silver and mercury haye been produced from the Merrill-Crowe milling circuit and from heap leaching. There are three heap leach circuits, Paradise Peak, Ketchup Flat and County Line. The Paradise Peak and Ketchup Flat heap effluent solutions are routed into the zinc precipitation plant which is associated with the mill for recovery of the precious metals. The County Lne hea lech circuit is a stand-alone operation, again with a zinc precipitation recovery circuit. The mill was shut down in May, 1993 due to depletion of ore reserves with the remainder of the heap leach ore due to be placed on the leach pads by late summer of the same year.

Jan 1, 1993

By Pierre Mousset-Jones, Geraint W. Harris, Robert Karlin, Jaak Daemen

In order to minimize the ore dilution induced by blast movement in surface mines it is necessary to quantify such movement. This will make it possible to more accurately locate the grade boundaries on the surface of a blasted rockpile prior to excavation. This paper describes the development and testing of a method to accurately measure the direction and magnitude of sub-surface blast movement. The technique involves the use of magnetic "radiometry, using a cesium vapor "radiometer and real-time differentially corrected, GPS system, to locate the post-blast position of magnetically enhanced target objects, whose pre-blast locations are known, without disturbance of the blasted rock. The objective is to design an accurate and efficient technique which can be integrated into a mines production cycle.

Jan 1, 1997

By J. J. Geldenhuys

Premier of the North-West Province, Mr Molefe, foreign dignitaries and guests, ladies and gentlemen. It is a pleasure and also a special honour for me to have been invited here this morning to make this address. The xv Congress of the Council of Mining and Metallurgical Institutions is, by its very nature, an extremely important event for the international minerals industry. But I believe that this specific Congress assumes an even greater significance because of the profound and far-reaching changes that have taken place in South Africa this year. These are exhilarating times, a period when so much in our country has altered and when so much has to be done so quickly to build positively on our bold political decisions.

Jan 1, 1994

By Gh. Crutu

The handling of radioactive waste deposits from factories that produce chemical fertilizers is a difficult problem, but has a great significance for soil quality and for the environment. The Romanian legislation has produced law and normative acts concordant with EU regulations for prevention and protection, and also for environmental contamination control with radionuclides. The soils and agricultural plants in the vicinity of phosphogypsum deposits are radioactively contaminated; the annual variability of the respective radioactivity values is demonstrated by annual records. Residual radioactivity monitoring determines the presence of radioactive ions in the soil and cultivated plants: wheat, maize, sunflower, as well as the spontaneous flora. The results obtained lead to the conclusion that ecological restoration works must be executed for degraded soils due to impacts of radioactive materials.

Jan 1, 2007

Sulphide Corporation Pty. Limited operates a Lead/Zinc Smelter at Cockle Creek, some 11 miles from Newcastle, N. S. W . Works effluents totalling some 8, 500, 000 gallons/day join Cockle Creek some 1. 8 miles from its mouth in the most northerly section of Lake Macquarie, The Creek is also the source of the Works cooling water intake of which approximates 8, 000, 000 g.p. d. In view of the wide use of the Lake for recreational activities by the people of Newcastle and the surrounding areas, particular care must be taken to ensure that the control of effluent quality is of a high order. This paper outlines the philosophy and measures taken for the treatment and control of plant effluents discharging into Cockle Creek.

Jan 1, 1971

By Bruce A. McKinstry

For many major mining projects the time frame from initial planning to production can be measured in terms of decades. Hecla's Silver Shaft project, which is scheduled to go into production by the end of this year and includes a complete surface facility, shaft with an ultimate depth of 2,348 meters (7,700 feet), complete ore pass and loading pocket system, and 610 meters (2,000 feet) of development drifting and stope preparation, was initially concieved in the Fall of 1979. This duration of a mere four years from conceptual engineering to production is a testimonial to what can be accomplished when a progressive mining company and an innovative contractor work together as a team rather than developing into two warring camps as often happens.

Jan 1, 1983

By James Boyd

It is obvious that mining has been influenced to a high degree by political and economic events, many of which are of such a nature that the mining industry has relatively little influence in shaping them. I cannot present too optimistic a picture for the immediate future, although I feel that from the long-range standpoint one need not be pessimistic about the future of the mining industry. The population of the United States is continuing to increase and with it has come an expanded consumption of metals on a per capita basis. With this expansion there has and will continue to come the demand for more goods and in- creased products from our mines and our fabricating plants. World War

Jan 5, 1950

By W. E. Newberry

The Aspen Mining District is situated at the eastern edge of the system of stratified rocks of western Colorado, where this edge meets the ridge of metamorphic granite which divides the State into two unequal parts. In following the valley of the Roaring Fork westward from the continental divide towards Aspen, one passes through a country of granite and gneiss, with no sedimentary rocks until the town is nearly reached. At this point the Cambrian quartzites first make their appearance, lying on the granites, with a dip of from 30' to 45 to the northwest. Beyond these quartzites and conformably upon them lie dolomites, limestones, shales, porphyries and sandstones, gradually flattening in general dip as one proceeds westward, but much disturbed by local foldings and faultings.

Jan 1, 1890

By M. Hayri Erten

In this research the possibility of pelletizing high grade fluorsoar fines or flotation concentrates with the use of calcined colemanite as binder is investigated, and the room temperature and elevated temperature strengths of these pellets are compared with those of pellets which are obtained by using bentonite as binder. Pellets of 10-12 mm. size and having 10% calcined colemanite showed a much higher room temperature strength than those containing 5% benonite, both being endurated at 1000°C for 15 minutes. However, when the same batch of pellets were tested at elevated temperatures of 250º to 500°C, bentonite gave better results. X-ray tests showed that in the pellets endurated at 1000°C for 15 minutes the original crystal structure of fluorite mineral is preserved.

Jan 1, 1977

With the sinking of the new No. 3 Shaft and the increasing depth and northward movement of the mining operations, improved ventilation of the mine workings became necessary and it was decided to sink a new upcast ventilation shaft midway between No. 2 Shaft and No. 3 Shaft.The shaft is finished to 16 ft. internal diameter and connects with the mine workings at the 2,600-ft. level. It is lined with unreinforced Concrete approximately 12 in. thick. The shaft sinking routine was drilling, blasting and mucking by hand using a 27-cub. ft. capacity bucket. The concrete lining was poured in conjunction with the sinking and was normally finished within 30 to 50 ft. of the shaft bottom.

Jan 1, 1957

By Igor P. Solozhenkin, Peter M. Solozhenkin, Sanda Krausz

"In this work, authors will show the efficiency of computer technology and chemical programs at studying collectors for flotation of minerals of elements of platinum group (EPG). Clusters various minerals EPG (flotation reagents) are created, named us clusters minerals (reagents) as their structure corresponds to the chemical formula, and the distance between separate atoms corresponds to the known tabulated data. By molecular modeling are investigated clusters sperrylite PtAs2, stumpfilyte PtSb, sadberryte PdSb, sobolevskite PdBi, palladoarsenyte Pd2As, paolovyte Pd2Sn, rustenburgyte (Pt3Sn, Pt6Sn2) and their computer parameters (absolute rigidity, electronegativity, transfer factors of carry, charges of the atoms) are determined. Tellurides of palladium (IV, II) merenskyite PdTl2 and kotulskyte PdTe and platinum clusters are investigated: PtFe4, Pt3Fe, PtFe (Pt2Fe2), Pt2Fe (Cu) Ni. The technique of attachment of the collector (composites) to cluster atoms EPG is offered. For the first time, it is established that at linkage of flotation collectors on monodentate, bidentate and bridged to circuits with atoms clusters the minerals containing atoms As, Sb, Bi, Pb, Sn, reaction of connection with change of a degree of oxidation of these atoms and occurrence of a proton operates. It is executed virtual skirling organic compounds connections by the developed criteria from accessible libraries of a database. The principle of an estimation of interaction energy for flotation reagents with mineral clusters is offered. It is developed the prognosis of collector activity evaluation (P?AE) and his values for candidates in collectors for flotation of minerals EPG are calculated. For flotation of ores containing Pt and Pd minerals, a number of reagents, including compounds on basis P (III), for innovational technology of Pt, Pd mineral flotation are recommended. Key words: flotation, minerals, flotation reagents on the basis of phosphorus (III), molecular modelling, chemical programs, program ????? , electronic energy."

Jan 1, 2014