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By D. J. Kemp

The 20th century saw changes in the mining and metallurgical industry not only technically but also in social and environmental expectations. As projects continue to become larger their visibility raises concerns among many groups. For mining companies, transparency, openness, and early engagement of all parties are fundamental to assure success. An equally important task is to anticipate the standards that will be required to meet society’s expectations in the 21st century.

Jan 1, 2005

De Beers? Finsch diamond mine began operation in the 1960s as a surface project using the latest technology available. During the 1990s, the operation, located about 160 km (100 miles) west of Kimberley, South Africa, began its move as an underground mine. The earlier stages (Blocks 1, 2 and 3) of underground work at Finsch used open stope mining methods, also using the latest in technology. The mine began developing Block 4 in 2004. How-ever, studies on this level showed that block caving was a more efficient mining method than open stoping. It was during those studies that De Beers determined that Block 4 would be a good candidate for testing Sandvik?s automated truck haulage technology.

Jan 1, 2008

By J. E. Scott, L. M. Heaman, R. A. Creaser, G. S. Salazar

"Schaft Creek is a calc-alkaline porphyry Cu-Mo-(Au) deposit located in northwestern British Columbia. The deposit formed in a volcanic arc setting, likely on a back-arc rifted continental fragment. It is hosted by Late Triassic basaltic to andesitic volcanic rocks of the Stuhini Group (Stikine Terrane), and is associated with porphyritic granodiorite dikes emanating from the nearby Hickman batholith. The age of the Hickman batholith is approximately constrained here by a composite U-Pb zircon date of 222.1 ± 9.6 Ma, which is in broad agreement with a well-constrained age for mineralization at Schaft Creek of 222.0 ± 0.8 Ma (Re-Os molybdenite). The deposit is in most respects typical of calc-alkaline porphyry systems, but displays silica-poor sericite-chlorite alteration in mafic country rocks in place of classic phyllic altera¬tion. The deposit comprises three distinct, but related, zones: the northern Paramount zone, the Main zone, and the West Breccia zone. Two phases of mineralization are observed. The first phase occurs as hydro-thermal veins and breccias, and minor disseminations. It consists of bornite, chalcopyrite, molybdenite, and pyrite with potassic and sericite-chlorite alteration. The second phase is minor and consists of veins of molybdenite ± specularite, as well as Cu-Pb-Zn sulfide veins without any significant corresponding alteration. Extensive structural modification has affected the deposit both during and after its formation.Schaft Creek est un gîte porphyrique de Cu-Mo-(Au) calco-alkalin situé dans le nord-ouest de la Colombie Britannique. Ce gîte s’est formé dans environnement d’arc volcanique, probablement situé sur un fragment continental bordé par un bassin d’arrière-arc. Le gîte est encaissé par les roches volcaniques basaltiques à andésitiques du Groupe de Stuhini (Terrane de Stikine) d’âge Triasique tardif, et est associé à des dykes de granodiorite porphyrique provenant du batholithe de Hickman avoisinant. L’âge du batholithe de Hickman est estimé par un âge U-Pb composite sur zircon de 222.1 ± 9.6 Ma, lequel est grossièrement en accord avec l’âge de la minéralisation de Schaft Creek, estimé a 222.0 ± 0.8 Ma (Re-Os sur molybdénite).Ce gisement, bien qu’à plusieurs égards typique des systèmes porphyriques calco-alcalins, présente une altération en séricite-chlorite pauvre en silice dans l’encaissant mafique a la place de l’altération phyllique classique. Ce gîte comprend trois zones distinctes bien que connexes : la zone Paramount au Nord, la zone Principale et la zone West Breccia. Deux phases de minéralisation sont observées. La première phase se présente sous forme de veines et de brèches hydrothermales ainsi qu’en disséminations mineures et consiste en bornite, en chalcopyrite, en molybdénite et en pyrite avec une altération potassique et en séricite-chlorite. La seconde phase est mineure et consiste en veines de molybdénite ± spécularite ainsi qu’en veines de sulfures de Cu-Pb-Zn sans association à une altération particulière. Le gisement a été profondément modifié par la déformation a la fois durant et après sa formation."

Jan 1, 2008

By M. J. Papo, A. Muwila

Hercules? is a low nickel austenitic stainless steel developed at Mintek that has a typical composition of 9 wt% Mn, 0.05 wt% C, 2 wt% Ni, 0.25 wt% N and 16.5 wt% Cr. A more corrosion resistant version of Hercules? (Hercules? B) with 0.5 wt% Mo has also been developed. Potentiodynamic tests performed on Hercules? B in a 5 wt% sulphuric acid solution showed it to have improved corrosion resistance comparable to that of AISI 304. The effect of a varying Mn content on the corrosion resistance of Hercules? B has also been investigated and the results discussed in this paper. From the corrosion test results, it is clear that decreasing the Mn content of Hercules? B increased the corrosion rate while increasing it decreased the corrosion rate. KEYWORDS Austenitic stainless steel, %ferrite, molybdenum, manganese, nitrogen, electrochemical corrosion tests, potentiodynamic scans, microstructure, chemical analysis.

Jan 1, 2006

It is a great honour to address our Institute as President, but the choice of a suitable subject was not an easy one. In the past when the presidential address was given at an annual conference the subject usually related to the conference or industry concerned; more recently the subjects have been more philosophical and this is a distinct advantage to me.I appreciate that I am addressing an informed audience and I am sure' that you are well advised in many of the points that I hope to leave with you. Unlike the specialist who gets to know more and more about less and less and eventually knows everything about nothing, I am one of the group who gets to know less and less about more and more and eventually knows nothing about everything.I hope you will appreciate this point whilst you are listening to me.In recent years I have been closely associated with the problem that troubles most governments of our time: the competition of many groups of differing backgrounds for the land that is available to the nation.This is of particular interest to the industry with which we are concerned as it is of critical importance to the discovery and development of future reserves of minerals and metals. Part of my daily task is involved with the administration of legislation for mining operations and the conditions under which such operations may be undertaken, in implementing government policies relating to mining, and in designing and administering legislationdirected to safety and health in mines.Most of our members are involved in exploration or in day-to-day problems associated with the production of minerals or the management of companies in these pursuits and would be aware of many of the conflicting viewpoints on priorities.F. F. Espie in his presidential address of 1975 'On being a minority', made the point that our Institute found that the mining industry had a great communication 'Problem with the Australian people.I believe that this is one of our major problems.

Jan 1, 1977

By P J. Grobler

The current commodity boom is depleting the ore bodies at a rate not seen in the past. As the existing ore bodies get depleted, only the more inferior bodies are left for exploitation. This places an emphasis on beneficiation to upgrade the lower grade ore to high-grade feedstock for downstream processes. This paper discusses the role of dense medium separation in this quest for high-grade feedstock for the future. It covers the production and utilization of ferrosilicon and gives a future perspective of the technology. It concludes about the way ahead and the challenges facing the processing fraternity and mining industry.

Jan 1, 2006

By Charles Stone, Madan Naik, Drupad Desai, Karel Rossler

Planning of New York’s new subway line dictated the location of shallow underground station caverns and track crossovers. Clear span openings ranging from70 feet to 100 feet and lengths in excess of 1000 feet, coupled with low rock cover ranging from 25 feet to 40 feet required judicious selection of construction methods, equipment, and proper sequencing of the excavation stages. Rock classifications alone could not predict the behavior of the rock mass during construction. A robust design procedure that considered most of the important aspects of rock behavior and elements of shallow tunnel design, minimized the negative impacts of variable geotechnical data. This paper describes the intricacies of the planning and design of the $16 billion Second Avenue Subway with insight into how to overcome the design complexities and construction challenges of the urban underground.

Jan 1, 2005

By L. C. IlsLey, M. W. Von Bernewitz

"Introduction.Several hundred thousand open lights are daily carried in coal mines of the United States, each lamp being a menace to life and property through fire or explosion. They have been responsible for many disasters in the past, and will be again. Flame safety lamps have been available for over a hundred years, but during the last ten years safe and practical electric lamps have been perfected. These have eliminated many of the flame safety lamps, and in a few mines have replaced open flame lamps. But there are still more than twice as many open lamps as electric lamps in our mines, and the open lamps should be discarded in favor of an approved type of electric lamp. There are several electric miners' lamps which have been approved by the Bureau of Mines for safety and efficiency, give good light, and are easily maintained and carried, some flame safety lamps will always be used, hut mostly for detecting gas; although they might be supplanted if some simple, reliable, and cheap gas detector were developed.Explosion Hazards from Open Lights.An open light and gas*** constitute a vicious hazard; while if there be coal dust present in the vicinity the consequences are multiplied many times. An open light and black blasting powder also constitute an explosion hazard, vividly attested by several serious disasters."

Jan 1, 1924

By M. Sibanda

The diffusion of carbon in Co-5% Fe alloy was studied in a belt-type pressure system at temperatures of up to 1330°C and press loads or nominal pressures of 7 020 tons or 42±3 kbar. Under these conditions, this alloy is in the solid state. Discs of graphite and prealloyed Co-5%Fe were used to make up the diffusion couple. The diffusion coefficient increased with increasing press load due to the tendency of the low density graphite to dissolve in the metallic phase reducing the overall volume and increasing the density of the system. Furthermore, inhomogeneous plastic deformation may have promoted diffusion by creating defects in the alloy. Diffusion couples treated at atmospheric pressure exhibited graphite particles in the metal, while those treated at high pressures exhibited carbide in the form of Widmanstatten laths. Carbon analyses indicated increased carbon solubility with increasing pressure. This was confirmed from calculated high-pressure phase diagrams.

Jan 1, 2005

By BUREAU OF MINES

This report is submitted in accordance with the provisions of the Synthetic Liquid Fuels Act of April 5, 1944 (30 U.S C. 321-325, as amended), which require that: "The Secretary of the Interior shall render to Congress on or before the first day of January of each year a report on all operations under this Act." Owing to the broad scope of the content and the diversity of interests represented, the Annual Report for 1953 has been divided into two separate publications. Each has been published by the Bureau of Mines as a Report of Investigations, and the respective titles follow: R. I. 5043, Part I - 011 From Coal. R. I. 5044, Part II 011 From 011 Shale. - Identical in each report, the introduction summarizes research progress made in 1953 under the entire Synthetic Liquid Fuels program. A free copy of each of these publications may be obtained by a written request to the Bureau of Mines, Publications Distribution Section, 4800 Forbes Street, Pittsburgh 13, Pa. The R. I. number and title of the publication desired should be indicated.

Apr 1, 1954

By J. H. Potgieter

This paper describes two cases of corrosion that occurred in dry-process, rotary, cement-clinker kilns. In the case of the kiln with five pre-heater stages, the attack occurred primarily from sulphates that probably originated in the raw feed and fuel being used in the plant and that penetrated the refractory lining. The corrosion was similar to ash-deposit corrosion often observed in steam boilers. In the second case the plant consisted of a long dry kiln with a single pre-heater fitted to the feed-end. In this case the corrosion could be ascribed to alkali chloride penetration through the refractory-brick lining and subsequent hot corrosion of the kiln shell.

Jan 1, 2004

The Arctic is a region of special economic, geopolitical, research, socio-ethnic, and defense interests of both Russia and other countries of the Arctic zone. Introduction of innovation technologies at ore-processing factories is a direct responsibility of the state and this problem should be solved on the basis of coordination of interests of different stakeholders. The task of elaboration of scientific principles of rational state regulation in the North is very topical. Innovations require considerable investments first of all from private capital. However as an investment object innovations are not attractive for investors as they require large expenditures for long-term projects, and they are connected to high risks because market incentives form striving to get quick profits of private companies and result in a certain behaviour strategy while innovations need ?long money?. Under such conditions without state regulation of investment and innovation activities development of the mining sector in the Arctic practically has no prospects. At innovation development of mining enterprises economic growth is provided at the expense of active state innovation activities. The elaborated strategy of ore-processing enterprises should correspond to the modern paradigm of the ore-processing industry development which is not only for extraction of minerals but also for multi-profile structure having comprehensive use of the resources on the rational basis intended for rational complex utilization of mineral resources of the AZR which by the definition includes maximally full use of the whole aggregate of resources on the economically rational basis with obligatory environmental with resource reproductive and socio-economic functions and deterrents. The main principle of creation of innovation technologies is to obtain more products of higher quality with minimal costs. This allows increasing ?productivity of the resources? several times. This principle makes increasing productivity of the resources the most important and in this case efficiency of use of the resources brings extra profits at the expense of lack of new costs such as payment for protection and utilization of wastes. According to the economic theory only ratio between demand and supply is able to fix optimal proportions in economy and to give necessary signals for investment activities of mining enterprises. In this context market for minerals and increase of mineral resources productivity do not create incentives for investment activities without which neither sustainable economic growth nor solution of macroeconomic tasks are possible. Nevertheless countries should not reject this idea in spite of economic efficiency of the enterprises. Extraction degree of useful components and especially oil in the Arctic zone is one of the lowest in the world. This can lead to crisis of oil industry and other mining sectors. The reason for that is lack of a state policy of realization of innovation technologies in the mining sector in the Arctic.

Jan 1, 2014

By Bjørn Nilsen, Werner Stefanussen

The construction of the Guaigui Multipurpose Project includes a 74 metre high concrete face rock fill dam, a 350 metre long diversion tunnel and a 350 metre long spillway tunnel. The topography in the project area is very steep, and the rock masses are characterized as soft rocks. The stability of the 80 to 100 metre high dam abutments and the excavation of the tunnels in soft rock conditions have caused various challenges and problems to be solved. Limited pre-investigations have called to a great extent for estimation of parameters for the stability calculations based on experience. The preliminary calculation of the stability of the planned rock slope above the spillway intake platform has been carried out by conventional partial factor methods and by use of a computed based Slide Program. The two methods of calculation give different results , and that rock support is necessary to obtain an acceptable factor of safety for a slope inclination of 52o. The input parameters for the rock mass characteristics need to be verified for the permanent calculations.

Jan 1, 2006

Jan 1, 1967

By B. G. Tarasov

This paper proposes the further development of a recently identified shear rupture mechanism (fan mechanism) that elucidates a paradoxical feature of hard rocks ? the possibility of shear rupture propagation through a highly confined intact rock mass at shear stresses that can be significantly less than frictional strength. In the fan mechanism, failure is associated with consecutive creation of small slabs (known as ?domino blocks?) from the intact rock in the rupture tip, driven by a fan-shaped domino structure representing the rupture head. The fan head combines such unique features as extremely low shear resistance, self-sustaining stress intensification, and self-unbalancing conditions. Consequently, the failure process caused by the mechanism is inevitably spontaneous and violent. Physical and mathematical models explain unique and paradoxical features of the mechanism, which can be generated in primary ruptures and segmented faults. The fan mechanism provides a novel point of view for understanding the nature of spontaneous failure processes, including shear rupture rockbursts. The process explains, in particular, features of shear rupture rockbursts such as activation at great depths, generation of new shear ruptures in intact rock mass, nucleation of hypocentres at significant distances from the excavation, shear rupture development at low shear stresses, and abnormal rupture violence.

Jan 1, 2014

By R. Hansson

Zincite and spinel phases are present in the complex slag systems encountered in zinc/lead sintering and zinc smelting processes. These phases form extensive solid solutions and are stable over a wide range of compositions, temperatures and oxygen partial pressures. Accurate information on the stability of these phases is required in order to develop thermodynamic models of these slag systems. Phase equilibria in the Fe-Zn-O system have been experimentally studied for a range of conditions, between 900 and 1580°C and oxygen partial pressures (pO2) between air and metallic iron saturation, using equilibration and quenching techniques. The compositions of the phases were measured using Electron Probe X-ray Microanalysis (EPMA). The ferrous and ferric bulk iron concentrations were determined using a specially developed wet-chemical analysis procedure based on the use of ammonium metavanadate. XRD was used to confirm phase identification. A procedure was developed to overcome the problems associated with evaporation of zinc at lowpO2s and to ensure the achievement of equilibria. An isothermal section of the system FeO-Fe2O3-ZnO at high ZnO concentrations at 1200°C was constructed. The maximum solubilities of iron and zinc in zincite and spinel phases in equilibrium were determined at pO2=1*10-6atm at 1200and 1300°C. The morphology of the zincite crystals sharply changes in air between 1200 and 1300°C from rounded to plate-like. This is shown to be associated with significant increase in total iron concentration, the additional iron being principally in the form of ferric iron. Calculations performed by Fact Sage with a thermodynamically optimized database have been compared with the experimental results. Keywords: Phase Equilibria, Fe-Zn-O, Quenching, Wet-Chemistry, EPMA, XRD, ISP.

Jan 1, 2004

By D. Ingram

"PRIMARY DUST COLLECTOR A. 42,000 CFM James Howden Fan Z-6 Size 3650 Fan Dia 40"" HP 75It was found that the fan was not large enough to remove the air that was displaced by the trucks dumping. So it was removed and an enclosure was installed to isolate the gyro from the rest of the building.B. FANSJames Howden Fans Model RPM 3500 Series 357 FW HP 10These fans were installed when the first dust system was put into operation. It was found that the high RPM and extreme fan wear caused a major maintenance problem. These fans were replaced with Chicage Blowers Model SWS1 RPM 1180 Dia 36"".DRY CYCLONE COLLECTORS A.,Three four foot rubber lined cyclones. Four six foot rubber lined cyclones.All under flow. Water is controlled manually and gravity flows to a central sump box. From there it flows to the grinding circuit in the Mill.Cyclone under flow product runs between 100 and 200 tons of dust per 24 hours with a screen analysis 30% + 400.The cyclone under flow product is diluted to about 3 to 4%. Solids total gallonage approximately 400.B.,Elbair Wet Scrubber125 HP RPM 56042,000 CFM,Model PX861The Elbair collects the total product from the discharge. Of the Cyclone fans the under flaw goes to the Mill - the Elbair discharges stack goes to atmosphere.The Elbair wet scrubber had to be redesigned in order to keep it in service."

Jan 1, 1976

By B. Valentim

The methodology used to obtain fly ash subsamples of different sizes is generally based on wet or dry sieving methods. However, the worth of such methods is not certain if the methodology applied is not mentioned in the analytical procedure. After performing a fly ash mechanical dry sieving, the authors compared those results with the ones obtained by laser diffraction on the same samples and found unacceptable discrepancies. A preliminary study of a wet sieving analysis carried out on an economizer fly ash sample showed that this method was more effective than the dry sieving. The importance of standardizing the way samples are handled, pretreated and presented to the instrument of analysis are suggested and interlaboratory reproducibility trials are needed to create a common standard methodology to obtain large amounts of fly ash size fraction subsamples.

Jan 1, 2008

By AIME AIME

PRACTICALLY all the Section delegates as well as a sprinkling of Institute officers and mere members were on hand for the annual business meeting of the Institute on Monday afternoon of the Annual Meeting. President McAuliffe presided, with C. H. Mathewson as associate chairman. Americo Albala was first called on to discuss the work of the Pan American Institute of Mining Engineering and Geology. C. Will Wright said that the need for such an organization was evident, and a resolution was passed asking the incoming President to appoint a committee to investigate cooperation with that body, of which Mr. Albala is executive secretary.

Jan 1, 1943

By Michael H. Wysockey

The load test program for the pile foundation at Soldier Field included static and dynamic load tests at four locations around the site. The dynamic tests were run with no knowledge of the static results, and comparison between the two is very good. It was necessary to use a special testing hammer (not the production hammer) to demonstrate capacity with dynamic testing. Over 90% of the piles were HP14x89 with a design load of 230 tons (18 ksi). The load tests showed a capacity in excess of 590 tons for all tests where sufficient set up time was allowed. The remainder of the piles were mostly HP 12x53 with a design load of 100 tons (13 ksi). The measured capacity of these piles was typically about 250 tons. One experimental HP12×74 pile with a nominal yield of 65 ksi held 730 tons (67 ksi) before failing.

Jan 1, 2002