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By Mwaba CC

Ok Tedi Mining Ltd has been using flotation for the production of copper/gold concentrates from a complex copper sulphide ore for several years. During this period, much effort has been devoted to metall- urgical treatment of the ore. This paper examines some of the mineralogical aspects of the sulphide minerals in the ore using the electron microprobe analyser. Results have revealed the complexity of the copper sulphide minerals and in particular, chalcocite. Analysis of both plant and laboratory flotation products has provided further insight into the effects of mineralogy on the flotation of copper and iron sulphides. A significant observation is that some of the pyrite minerals apparently exhibit natural floatability. The implications of the mineralogical characteristics of the sulphide minerals on the flotation of the ore are also discussed.

Jan 1, 1991

By V. R. Spironello

The Bureau of Mines is involved in research directed toward the utilization of municipal solid waste. One of the primary objectives is the recycling of the magnetic fraction of municipal solid waste (raw refuse). This is consistent with one of the Bureau's goals, which is to minimize the requirements for mineral commodities by maximizing metals recovery from secondary domestic resources, In this investigation, cupola trials were made using combinations of refuse scrap with shredded automobile scrap under basic and acid slag practices. Furnace operating information and the behavior of alloying and tramp elements was obtained. The research showed that it is possible to utilize up to 60 percent refuse scrap in the cupola under basic practice and 30 percent under acid practice, Aluminum in refuse scrap, present in bimetallic cans, increased the recoveries of silicon and manganese charged to the cupola. Increased use of refuse scrap provided iron of lower sulfur. The alumina resulting from oxidation increased the slag volume. The aluminum and tin contents of the iron increased with increasing levels of refuse scrap in the charge. Lead was not a problem with respect to contamination of the iron. In basic practice, operation of the cupola was satisfactory since all slags were adequately fluid. In acid practice, operation became troublesome above the 45-percent level. Under both practices, the cupola iron melting rate decreased. Particulates in scrubber water and stack condensate samples contained lead, zinc, and tin, and the dust load increased. The tensile and transverse strengths of the iron produced under both practices are reported.

Jan 1, 1980

By R. H. Oitto

To determine whether reflectors could substitute for the trip lights referred to in the Federal Mine Safety Code, the Bureau of Mines studied trip safety devices under simulated haulageway conditions. The noticeability of reflectors compared with trip lights and fluorescent panels was evaluated from distances of up to 850 feet with light source intensities of up to 1-6 foot-candles (ft c). Reflectors tested consisted of a reflective lens in a holder secured to a frame that can be attached to a trip. Reflectors were found to be suitable for use as a trip safety device. In fact, for the conditions in many underground haulageways some reflectors would be more effective than a permissible trip light.

Jan 1, 1968

By Andrew Port, Ali Ghandeharioon

Nonlinear seismic deformation analyses using the finite difference program FLAC were performed for a wastewater treatment plant to estimate foundation displacement and performance of two proposed trickling filters during the 2475-year event design earthquake. The effective stress based constitutive model UBCSAND, which captures the cyclic behavior of both the “sand-like” and “clay-like” materials, was used to model the dynamic response of the soil strata. Dynamic analyses of the site indicated that in absence of ground improvement or deep foundations beneath the proposed trickling filters, those structures would undergo horizontal displacements in excess of 1 m and short-term differential settlement gradient of about 400 mm over 50 m as a result of seismic and post-seismic settlements. Three mitigation options were considered for limiting the seismic displacements and differential settlement gradients of the proposed trickling filters. These alternatives include vibro-replacement stone columns, vibro-replacement stone columns plus supplementary cutter soil mixing (CSM) configurations, and pile foundations. Various layouts for each mitigation option were considered including the lateral extent of the ground improvement, CSM walls and pile spacing. Seismic horizontal and vertical displacements of the proposed structures as well as post-earthquake consolidation settlements due to dissipation of excess pore water pressures in soil layers were assessed in all the analysis alternatives. The analyses indicate that all the alternatives considered have the potential to provide a comparable level of seismic and post-seismic performance. However, for similar performance levels, the ground improvement options need to extend well beyond the edges of the proposed structures, while the piles can be limited to just beneath the footprint of the structures. INTRODUCTION Annacis Island Wastewater Treatment Plant (AIWWTP) is owned and operated by Greater Vancouver Sewerage and Drainage District and services a population of approximately 1 million people in Vancouver, British Columbia. Wastewater is generated by residential, commercial, and industrial sectors and the treated effluent is discharged to Annieville Channel of Fraser River on the south side of Annacis Island. AIWWTP is located on a 51-hectare site and was commissioned in 1975 as a primary treatment plant, but has had two major expansions to meet the population growth needs, and to improve the treatment process efficiency through the provision of secondary treatment of the liquid stream. The current expansion includes construction of additional solids contact tanks and secondary clarifiers. Future expansions include the construction of proposed additional trickling filters. New expansion structures are required to be designed for post-seismic operation after the 2475-year event design earthquake.

Jan 1, 2018

By F. P. Hassani

Today, mine backfilling has become an integral part of mining operations, both from a local and overall ground control point of view, and as regards mining techniques and environmental considerations. During the past decade, substantial research has been carried out to contribute to the better understanding of the mechanisms involved in mine backfill behaviour. This work involved analytical, experimental and numerical studies at different scales. Accordingly, this work has been aimed at developing backfill design guidelines for actual working conditions. Backfill design for deep mining conditions is complex and requires understanding of various elements. The most important of these elements are: backfill inherent strength parameters, backfill placement method, stope geometry and interaction between backfill and host rock. The mobilization of backfill strength parameters controls the backfill behaviour and thus, its failure mode. It is believed that the governing boundary conditions and backfill-rock interaction influence the backfill strength mobilization significantly. Accordingly, the interaction between backfill and host rock is an influential factor in overall backfill behaviour under applied loads. The focus of this research is to investigate the backfill-rock interaction, considering a nonlinear behaviour for both backfill and rock mass. Assuming typical stope geometry, the FLAC code was used to model the complex boundary condition associated with narrow vein mining conditions and to simulate the backfill behaviour. A comprehensive numerical study was conducted and the results obtained were compared against field observations. The analysis of findings provides qualitative results, which can be used for backfill design. Keywords: Numerical modelling, backfill, deep mining, non-linear behaviour, rock mechanics, backfill behaviour, narrow vein mining.

Jan 1, 2008

By Michael G. Zabetakis

Vaporization of a solvent into an airstream at temperatures above the flash point of the solvent is hazardous if vapor is liberated at a rate that is sufficient to produce a flammable mixture. In may operations, the formation of such a mixture is prevented by rapid diluton of the vapors with air. The minimum air requirements for the dilution process are determined by the composition of the lower limit mixture at the temperature and pressure of interest. Because limits of flammability cannot always be calculated with sufficient accuracy for a proposed operation, they .rust often be determined experimentally. The present Bureau of Mines investigation was prompted by an application in which the lower limits of flammability of a number of solvent mixtures were required over a range of temperatures at atmospheric pressure. These limits were to be used along with available solvent-vaporization-rate data to establish minimum airflow rates needed to prevent the formation of flammable mixtures in an industrial process. Lower limits of flammability were determined for a number of mixtures containing methyl ethyl ketone, tetrahydrofuran, toluene, ethyl alcohol, and ethyl acetate in dry air-at atmospheric pressure and temperatures between 16° and 200° C. The experimental values were found to be in good agreement at with those predicted by Le Chatelier's law; variations with temperature were in fair agreement with those predicted by a modified Burgess-Wheeler law.

Jan 1, 1962

By D. R. Derry

"IT WOULD TAKE a braver man than I to try to forecast the future of mining exploration far into Canada's second century. Even to look ahead ten or twenty-five years we must review the figures of the fairly recent past -and I have found this quite a time-consuming but interesting job -in order to find trends and project them into future years. The trends to which I will refer are: firstly, the annual expenditure on exploration and its relation to value of output; secondly, the discovery rate and its relation to production initiations; and thirdly, the methods by which discoveries have been, and will be, made. Exploration Expenditures Figures on the annual expenditure on mining exploration in Canada have been collected and published for some years by the Do-minion Bureau of Statistics. These have some unavoidable limitations; e.g., in the varying definition between one company and another of what comprises ""Exploration"" and in the difficulty of getting complete returns. However, although the actual figure for a given year may be subject to question, I believe that the relative figures from one year to another are reasonably reliable. There is also a lapse of time between the collection of data and publication -the last published figures are for the year 1963. In bringing the figures up to date to 1966 I have canvassed eight of the larger mining and exploration companies and obtained their figures for 1963 to 1966 inclusive, and then averaged these for each year and applied the progression to the 1963 figures."

Jan 1, 1968

Previous methods for measuring the flow of solids in Jnrdraulic conveying have not considered the important effects of slip velocity and particle concentration. In this paper an extension of the method proposed byShirato et al. (J. Chem. Engng. 'Japan, 1: 164-167) for determining mass flow in a vertical conduit is outlined.The present method consists of measuring' the volumetric flow of the slurry (by a magnetic flow meter for instance) and the density of the slurry in two pipe sections of different diameters. Effects of variation of slip withparticle concentration, not previously considered, are allowed.Problems involved in estimating the density of a slurry from differential pressure measurement are discussed.The major problem is the uncertainties in estimating frictional losses due to the wall in two-phase flows. The greater reliability of a more "direct" technique, such as by 'Y-ray absorption, for measuring solid concentration is emphasized.

Jan 1, 1971

By Patrick Pelletier Jr., Pierre-Alexandre Bossé, Gianni Bartolacci, Ian Orford, Steve Parent

"Over the last decades, many authors have shown the importance of froth in the flotation process. Mineral recovery is related to froth recovery and flotation. Selectivity is affected by froth characteristics, especially structure and loading. The characteristics of froth textures could therefore be used for diagnosing flotation.Machine imaging, especially image texture analysis, allows on-line measurement of important froth characteristics and process state classification. The measured characteristics include froth texture, loading and stability indicators. To extract information from images, texture analysis tools are used as well as a block-matching algorithm (BMA). For process state classification, images are analyzed with the same tools and clustering is done with multivariate data analysis algorithms.Two case studies, Brunswick Mine Concentrator Cu/Pb circuit and LaRonde Mine Zn circuit, are presented to show that these indicators may be used for diagnosis and control. The influence of manipulated variables on measured froth features is shown as well as the relationship between froth characteristics, mineral recovery and flotation selectivity.INTRODUCTIONImaging is a way to depict abstract characteristics of a scene or an object; it is often related to other types of scientific observations, chemical component concentrations, for example (Geladi and Grahn, 1996). In this paper, the scene is flotation froth. Imaging can be especially useful in applications where it is difficult to obtain the measurements needed for process analysis – froth flotation, for example."

Jan 1, 2006

By Robert Hopler

As a part of the depression and rectification work on the Port Morris branch of the Harlem Division of the New York Central & Hudson River Railroad, a short tunnel is being driven under St. Mary’s Park. The park is near 149th St. and St. Ann’s Ave., in the Borough of the Bronx, New York City.

Jan 1, 2006

By Ludimila Melo Vieira

O foco deste estudo é avaliar a capacidade de dissolução das partículas de cal a uma temperatura próxima da fase inicial de sopro do processo BOF. Os testes foram realizados em um forno elétrico utilizando amostras de Cal com diâmetros de 6 mm e 9 mm, 80% e 100% calcinadas em diferentes basicidades de escoria. Os resultados mostram que com o menor nível de calcinação a dissolução foi mais rápida. Podendo ser atribuído a algumas diferenças na porosidade da cal ou um efeito de formação de espuma observado durante os testes devido à evolução do CO2 da calcinação restante. O aumento na basicidade da escória resultou na redução da taxa de dissolução que pode ser atribuída a uma precipitação de fase sólida mais densa na interface das partículas aumentando a viscosidade da escória e reduzindo a porosidade da partícula. A partir de um modelo de regressão linear o nível de calcinação mostrou maior efeito sobre o coeficiente cinético do processo de dissolução seguido do tamanho de partícula. O efeito mais fraco foi a basicidade da escória. Este resultado sugere que a área de contato cal escória parece ser mais significativa do que a viscosidade no processo de dissolução de cal nos presentes experimentos.

Oct 30, 2017

By Andreas Munko

A Outotec está desenvolvendo em escala piloto o queimador de baixa emissão de NOx desde 2012, resultados expressivos foram atingidos (o pedido de Patente já foi depositado). Em 2014 utilizando simulações CFD, os resultados atingidos em escala piloto foram reproduzidos com boa aderência e os resultados em escala industrial se mostram com os mesmos comportamentos em tendências dos resultados da escala piloto, se mostrando promissores também. O presente trabalho apresenta os passos de desenvolvimento, os promissores resultados e o próximo passo deste desenvolvimento é realizar um teste em escala industrial com o queimador desenvolvido.

Aug 17, 2017

By D. Bitzios, A. Gracia, V. Meggiolaro, J. D. Baker

Synthesis report on a project carried out under the EC-funded BRITE-EURAM programme. A large deposit in Spain and several smaller ones in Greece and Sweden were investigated. Beneficiation testwork, including the development of an innovative wet circuit, was undertaken in Italy. The Spanish Ilustracion deposit lies occurs in thin, white layers throughout a zone 35-40 m thick and 1.5 km long, in laminated calcsilicates. Total resources of more than 100 000 000 t include proven open-pittable reserves of 4 500 000 t averaging 35% wollastonite. The beneficiated product is suitable for various applications, including ceramics. The Swedish and Greek marble-hosted skarn deposits include Albatross, with 2 500 000 t of reserves at 30% wollastonite, and Panorama, with reserves estimated at more than 700 000 t

Jun 21, 1905

By Qingwei Wang

This study focused on acidic wastewater from producing sulfuric acid system in zinc smelter containing mercury 21.48mg/L, zinc 55.85mg/L, lead 38.50mg/L, copper 1.68mg/L, cadmium 10.25mg/L, As 29.86mg/L treated by biologics. The factors of pH value, the ratio of biologics to mercury, complexing time, hydrolytic time and temperature were studied in this paper. Experimental results indicated that at pH value 10, quantity of biologics to mercury ratio was 16, complexing time 30min, hydrolyzation time 20min, temperature at 40?, concentration of mercury in treated water was removed to 22.15µg/L. At same time heavy metals such as Zn, Pb, Cu, Cd, As was removed by biologics, the remained concentration in treated water was Zn 0.53mg/L, Pb 0.12mg/L, Cu 0.01mg/L, Cd low to 0.01mg/L and As 0.023mg/L. According to EDAX analysis, mercury content in complexing sediment reached 28.49% easily to recycle as raw material and low concentration of heavy metals in hydrolytic sediment easily to dispose and treat.

Jan 1, 2009

By Thomas J. Ferree

A Reichert cone concentrator was installed in an aggregate plant circuit to recover the extremely fine "flour gold" known to exist in the deposit. The gold content of the bank-run gravels averages about 0.1 grams per ton (about $1.45 per ton), based upon $14.47/g (345O/ounce) gold. Tine Reichert cone, in conjunction with a conventional shaking table, re- covers in excess of 85% of the gold. A screen analysis of the gold particles shows 44.1% is -i4 microns (-200 mesh) in size. The plant operates with a two-man crew.

Jan 1, 1981

By Danny Riley, Brian Curry, Sandya Govindaraju, James Bain

Acute vibration causes vasoconstriction in naïve human subjects1. Vibration-induced decrease in skin perfusion has also been reported in the rat-tail vibration model 2. After vibration exposure, rat-tail arteries demonstrate vacuoles in smooth muscle cells, similar to that caused by pharmacological vasoconstrictors3. This study addressed the effects of different frequencies, durations and patterns of vibration on lumen size and vacuole formation using the rat-tail vibration model in male Sprague-Dawley rats (~300 g). Methods The different groups were: 4-hr continuous vibration at 30, 60, 120 and 800 Hz; continuous exposure durations of 5 min, 1 hr and 4 hr at 60 Hz; and 4-hr cumulative exposure of 60 Hz delivered intermittently in cycles of 10 min on and 5 min off. Acceleration was set at 49 m/s2 r.m.s. for all frequencies. Unanesthetized rats were restrained in cages on a nonvibrating platform with their tails placed on a vibrating stage driven by a B&K motor (4809). The sham control animals were also placed in the vibration apparatus but not vibrated. Room temperature was controlled at 25 ± 1°C. Ventral arteries from proximal tail segments 7 were immersion fixed in aldehydes, embedded in epon-araldite and sectioned (0.5 µm) for morphological analysis. Vascular lumen sizes were measured as the percent ratio of the lumen perimeter to internal elastic membrane length using Image J software (NIH). The number of vacuoles in the smooth muscle layer of each artery section was counted. Results Fig 1: Semithin sections of arteries. A. Sham control. B. 4-hr vibration 60 Hz. In vibrated arteries, the lumen decreases in size, and smooth muscle cells (SMC) exhibit vacuoles (arrow). Bar equals 40 µm for each panel. [ ]

Jan 6, 2006

The opening session of the A. I. M. E. was held at the King Edward Hotel, Toronto, on Tuesday, July 25th. Dr. W. G. Miller, on behalf of the Local Committee, opened the proceedings. [ ] President John Hays Hammond, who occupied the chair, introduced Alderman Graham, Chairman of the Reception Committee, and representative of the city, in the absence of His Worship the Mayor. A brief address of welcome was delivered by the Alderman and responded to by President Hammond. The President then requested Dr. James Douglas to present to the honoured Secretary of the Institute, Dr. Rossiter W. Raymond, an oil portrait.

Jan 1, 1907

By Stanton Johnson

Africa has a long history of mining and has been one’of the world’s greatest sources of gold and other mineral resources since the days of the Egyptian pharaohs. Mining in Africa has been dominated by South Africa since World War II. However, in the past 10 to 15 years, other African countries are beginning to slowly catch up with South Africa. Ghana, formerly called the “Gold Coast” is located on the West Coast of Africa. Ghana has been involved in mining activities for well over 100 years. Most of the mining activities centered on the mining of gold and were to a large extent limited to underground mining methods. With a more liberal economic policy regarding the exploration and exploitation of Ghana’s mineral resources, mining activities are beginning to evolve to a much larger scale. Drilling and blasting which is an important aspect of this evolution is also changing due to the involvement of foreign-based mining and explosives companies.

Jan 1, 1998

By Cyro Takano

A tecnologia de autorredução apresenta um grande potencial por apresentar características de alta velocidade de redução e de eficiência energética, resultando em economia de energia e em alta produtividade na produção de metal primário. Têmse dois processos consolidados de aglomeração. A utilização de cimento como aglomerante, com cura a frio que formam hidratos que conferem resistência, apresenta problema principal de sofrer degradação às temperaturas na faixa de 800 a 1000 °C, devido à decomposição dos hidratos. O outro processo é o de utilização das propriedades do carvão de alta fluidez e tratá-lo termicamente para que sirva de redutor e aglomerante. Este processo não é o de cura a frio, porém diminui consideravelmente a quantidade de escória em comparação com a utilização de cimento. O objetivo deste trabalho é o de analisar, na literatura técnica, os aglomerantes alternativos e iniciar os ensaios para verificar os comportamentos de resistência mecânica, principalmente a quente. Em função dos resultados a etapa seguinte será a de projetar um processo que seja compatível com resistência mecânica a quente. A análise resultou em sugestões para os ensaios. Os resultados preliminares, com utilização de bentonita e ácido bórico estão indicando resistência a quente das pelotas melhores que as obtidas com a utilização de cimento.

Aug 17, 2017

By Lucius W. Mayer

The iron-mines of the Ilsede Hütte Co. are at a town called Peine, about 20 miles east of the city of Hanover, on the railroad to Brunswick (Braunschweig). Hanover, the capital of the province, is a military city, of approximately 250,000 inhabitants, and Brunswick, 33 miles to the westward, has half this number. The mines here described are located in a hamlet called Bülten. The Ilsede Hütte Co. operates two mines, 1.5 miles apart, in this district, Gruber Bülten Adenstadt and Gruber Lengede Bodenstadt. It also operates an iron-mine north of Hanover, known as Eiserhaven, and one in the Harz mountains, the Georg Friedrich, at Grauhof. At Bülten a coarse conglomerate, a, Figs. 1 and 2, contains nodules of limonite, cemented together by calcium phosphate. The ore contains Fe, 25 to 45; Mn, 3 to 4; P, 0.6 to 1.4; S, 0.02 to 0.09; and CaCO3, 40 per cent. Directly above the conglomerate is limestone, b, followed by a mixture of clay and sand, c. Below the conglomerate is a hard clay floor, d. The ore-body, from 10 to, 12 km. long, and from 3 to 4 km. wide, has a maximum thickness of 20 m. It clips approximately 10° S.E., and strikes N. 45° E. Diamond-drill prospecting shows that the thickness diminishes to 1 m. as the end of the deposit is approached to the northward. At this point the deposit is 250 m. below the surface. In Fig. 2, the arrow, A, indicates the general direction of the work along the face, a, which is carried forward in a straight line for its entire length. At B, a train is approaching, which has come from the bench-track, shown at G, by a circuitous route, and is dumping the overburden behind the face, in the space left by the excavated rock. Formerly the work at this mine was essentially open-cut, the deposit having a very strong outcrop. Figs. 1 and 2 show also

Sep 1, 1908