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By M. Brochu

In this paper, we present a computer-vision approach developed for wall-thickness measurements of corroded pipes inspected by double-wall radiography. The main objective of the work is to optimize data collection and film interpretation using computerized image analysis. To date, the system is able to identify the inner and outer contours of a pipe and perform wall thickness measurements at each pixel of a radiograph. This will be presented by analysing pipes having different dimensions. Another important feature of the system concerns the algorithms' adaptability to pipe wall texture. In other words, image analysis is automatically refined around rough or corroded areas. This allows more precise thickness measurements and shape identification in critical sections as will be demonstrated with examples. Finally a brief overview of results exploitation will be given and compared with human interpretation. It will show the reliability of automated image analysis and the many possibilities offered by complete output analysis.

Jan 1, 2005

By Charles Preble

El presente texto refiere la producción y consumo del cobre desde 1980 a 1984, deficiencias, reducción de costos y consumo a nivel nacional.

Nov 1, 1985

By R. G. Siddall, W. Gale

In the UK the development of the science of strata control has been strengthened by a resurgence of interest in the specialism of roofbolting and its associated techniques. The evolution of the theories and practices of strata bolting in roadway stabilisation is discussed. Practical experiences are considered, principally the use of Australian techniques, the relationship between bond strength and annulus and the effects of stress in the ground. Areas of new technology such as cable bolting, injection anchors and on-board bolters are also discussed. The recent advances in computer technology and rock testing equipment and methods have provided the opportunity to simulate ground behaviour under various conditions. Computer modelling developments and the use of techniques to predict ground behaviour are described.

Jan 4, 1992

By E. Siami-Irdemoosa, S. R. Dindarloo

Ease of excavation or rippability, also called diggability or excavatibility, is a critical decision-making parameter in the selection of both the overburden removal method and the required equipment in surface mining and geotechnical engineering projects. The most widely used method of estimating rippability is rock mass classification. Although there are different classification schemes in the literature, all of them have the two major limitations of sharp transitions at class boundaries and subjective uncertainties in decision making. In this study, the decision trees method was employed as a classification tool for estimating ground rippability, using the four rock mass parameters of weathering degree, uniaxial compressive strength, joint spacing and bedding spacing. The results were compared with those of the widely used method of diggability index rating (DIR) and a fuzzy-based DIR. The problem of subjective uncertainty was resolved in the proposed decision trees method, as the tree rules were derived automatically from the training data sets. Compared with fuzzy-DIR, a decision tree classifier is simpler, needs less computational time and is more appreciable by industry practitioners. Nevertheless, the proposed method is not flawless and, similar to both the conventional and fuzzy DIR methods, yielded poor estimations in particular instances. The limitations of the three methods are discussed.

Jan 1, 2015

By R. Venugopal

Hydrocyclones have been used extensively for more than 100 years to classify mineral slurries for recirculation in grinding circuits. Sometimes hydrocyclone classification is carried out in more than one stage to improve the efficiency of classification. Factors affecting separation efficiency include fluid velocity, density, and viscosity as well as the mass, size, and density of the particles. The geometric configuration also affects its efficiency; it includes parameters like cyclone diameter, underflow and overflow diameter, position of vortex finder, height of the cyclone, feed inlet geometry, and diameter etc. Besides changes in the basic parameters some modifications in cyclone has also been introduced from time to time which have affected its efficiency, some of these are :-(i).Introduction of magnetic force along with the centrifugal and drag force to control the flow of the magnetic particles inside the chamber.(ii). Introduction of sparger, air is introduced in the chamber in the form of bubbles, to control the flow of fine particles and hydrophobic particles. (iii). Introduction of dilution technologies for the dilution of thickened underflow. (iv).Introduction of new model. In spite of wide use and simple geometry, the real working principle of hydrocyclone chamber is extremely complex because of the swirling turbulent flow inside the device. In order to get more knowledge about hydrocyclones and to increase its efficiency, past 10-15 years simulation techniques are being developed. The simulation models also enabled a deeper insight into the static and dynamic behavior of hydrocyclones. Therefore, more emphasis on simulations by methods like Computational Fluid Dynamics (CFD), Finite Element method (FEM) is given. Overall, a status review of the work carried out on the analysis of hydrocyclone performance, modeling approaches and its contribution in the efficiency of mineral processing operation is highlighted.

Sep 1, 2012

By Ian Sheppard, Kugan Kuganathan

The Mount Isa Rocky Paste Fill (RPF) was one of the five fill options investigated for the Enterprise Mine filling between June 1996 and September 1996. Co-disposal of deslimed cemented tailings (CHF) and suitably graded rockfill (RF) in certain ratios produced the rocky paste fill. The RPF behaved like a cohesive paste with very high proportion of rockfill in the mix. Several large-scale mixing trials and drop tests proved that the rocky pastefill results in a homogeneous fill mass after placement. Segregation of RF was a common problem with MIM's traditional cemented rock fill (CRF), which is a combination of CHF and RF. The segregation was eliminated and a non-segregating paste like fill was created by optimising the particle size distribution of RF, and combining the RF and the CHF in optimum ratios. In rocky pastefill, the excess water in the cemented deslimed tailings slurry is taken up by the rockfill as the surface moisture on the rockfill particles and also as pore water between the particles. This results in thickening of the CHF, and the resultant mix is a non-segregating cohesive paste, which can easily spread to any horizontal distance inside a stope at a very low surface angle. The rocky pastefill releases no free water and relatively more pervious than the standard CHF due to rockfill component. With an average cement addition of 1.5 to 2% the rocky pastefill can develop higher strengths over 1Mpa. The rocky paste fill is applicable in many situations and can accommodate a variety of coarser materials that would be available in different mine sites. This paper present the research work and the experience associated with the rocky paste fill, and gives clear design principles for any potential users.

Jan 1, 2001

By C. I. Basilio

The adsorption of dialkyl di-and mono-thio-phosphinates on gold, silver and gold-silver alloys has been studied in the present work. These reagents, which are selective collectors for sulfide flotation, have been found to improve precious metals recovery from ores. Voltammetric studies have indicated that dithiophosphinate adsorbs on gold at much higher potentials than on silver, while monothiophosphinate adsorbs only on silver. However, both adsorb on gold-silver alloys with the adsorption potential decreasing with increasing silver content. Using FTIR spectroscopic measurements, the surface species formed during the interactions of these collectors have been identified. The results of the electrochemical and spectroscopic measurements have been compared with the contact angle data obtained at controlled potential conditions.

Jan 1, 1992

By Vince Newberry

Alcan Rolled Products at Oswego, New York, commissioned Recycle II during May of 1995. Recycle II is an advanced technology UBC recycling facility designed to meet the most stringent environmental standards enforced to date in the United States, particularly with respect to NO, and particulate emissions. This paper addresses the exacting requirements and strategies of Alcan's Recycle II project andThorpe Technologies' design considerations and solutions for the supply of environmentally favorable melting furnace and delacquering systems. The furnaces are equipped with low NOx regenerative burners and furnace pressure and hearth gas flow controls designed specifically for processing the hearth gases through baghouses. The delacquering system is a new generation Apros concurrent flow unit designed for low NOx emissions.

Jan 1, 1995

By Jeremy Spearman, Mark Lee, Jon Taylor, Neil Crossouard, Bramley Murton

"SUMMARYThis paper describes challenges faced when executing a programme of monitoring to measure the dynamics of currents and sediment plumes at a seamount and the solutions identified to deliver the measurements. The study site was the Tropic Seamount, which extends some 3300m above the surrounding seabed and is found at the southern limit of the Canary Island Seamount Province. The purpose of the study, which forms part of the Marine E-tech project, was to provide information on the interaction of flows with the seamount and to assess the behaviour of sediment plumes that could be generated from potential seabed mining operations targeting the recovery of ferromanganese crusts. Since the crest of the seamount is submerged to a depth of 1000m, much of the work was undertaken using remotely operated and autonomous vehicles supported by measurements from the surface vessel. Despite only limited information on currents being available for planning purposes, the combination of short term forecasting using a 3-dimesional hydrodynamic model of the study area coupled with the collection and analysis of reconnaissance data collected during the first phase of measurement activities made it possible to plan and execute a number of detailed hydrodynamic experiments on the seamount crest. The results of these experiments have advanced the understanding of the behaviour of sediment plumes in the deep ocean and will ultimately improve our ability to manage the impacts which may arise from deep sea mining operations."

Jan 1, 2017

By D. F. Scott

"DEFINITION OF THE REGION AND ITS BOUNDARIESTHE REGION of Western Canada covered by this re-port lies between the Precambrian rocks of the Canadian Shield and the structurally deformed rocks of the eastern Cordillera, extending northward from the international border to the 60th parallel. It is some 487,000 square miles in area, with a total sedimentary fill of about 535,000 cubic miles0>. It includes parts of the prairie provinces of Manitoba, Saskatchewan and Alberta and the northeast corner of British Columbia and forms part of the geological region known as the Interior Platform, commonly referred to as the Western Canada Sedimentary Basin. The bedrock comprises carbonates and evaporites of Paleozoic age that lie on Precambrian crystalline rocks and are over-lain by a relatively thick blanket of Mesozoic and Tertiary elastic rocks. The nearly flat-lying bedrock, covered by a thick mantle of glacial drift, forms the Interior Plains physiographic province."

Jan 1, 1970

By J. C. Underwood

"The wear performance of grinding balls under conditions of impact and abrasion is affected by their chemical composition and structure. The selection of appropriate analyses and heat treatments that will provide both abrasion and impact resistance takes into account the effects of certain elements on structure and harden-ability, as well as the over-all effect of composition and hardness penetration on the residual stress pattern developed through heat treatment. Direct quenching from forging temperatures substantially increases hardenability over that obtained in reheat-quench practices, and can be done without undue risk of damage to the ball provided that the harden-ability bears the correct relationship to ball diameter.Average volumetric hardness and percent hardened volume are convenient parameters for quantitatively expressing the response to heat treatment and indicating anticipated wear properties. A number of factors which can lead to reduced wear life as a result of material or processing problems are reviewed and illustrated."

Jan 1, 1959

A brief description of the hydro-gen reduction of nickel from ammoniacal solutions by the Sherritt process is given, indicating how this procedure can now be used to coat a great number of materials -particularly powders -with nickel or cobalt, whereby so-called composite powders are produced. The technique for the production of composite powders is described, particularly with regard to the surface activation of noncatalytic powders, whereby it is possible to coat core powders uniformly with nickel or cobalt. The properties of some of the more interesting composite powders, such as Ni/ AI, Ni/WC, Co/WC, Ni/Graphite and i/P, are discussed as well as possible fields of application for these new products. INTRODUCTION DURING the last decade, no-table advances have been made in pressure hydrometallurgy, so that large quantities of three of the more com1r.on metals, copper, cobalt and nickel are now produced on a commercial scale by hydrometallurgical processes.

Jan 1, 1963

By Lincoln McCrabb

Correct measurement and interpretation of viscosity data is critical for design of any thickening and pumping process that involves a non Newtonian slurry. The nickel laterite pressure acid leach (PAL) process relies on producing a slurry of maximum achievable solids concentration. Small variations of 1-2% solids concentration can alter economics significantly. For the Ravensthorpe Nickel Project, a rheology protocol has been developed which optimizes the solids concentration across a range of ore types. The vane yield stress technique has been utilized to accurately quantify the flow of thickened slurry in the lower shear range. A yield stress of 100Pa has been used as a benchmark to determine the optimum solids concentration achievable utilizing deep cone thickening. Statistical analysis of the data shows critical rheology distinctions between ore type, particle size, lithology and geochemistry. Linear and power law models have been applied to rheology flow curves to reconcile the material transport properties with the anticipated thickener underflow solids concentration. Keywords: Vane Yield Stress, Thickening, Rheograms

Jan 1, 2004

By Talita Gama de Sousa

Determinadas aplicações de magnetos pulsados ocorrem sob a ação de campos magnéticos elevados, (= 100 T). Esses campos provocam efeitos tais como, elevadas tensões tangenciais (hoop stress) produzidas pela força de Lorentz e conversão de parte da energia elétrica em calor (efeito Joule) que deterioram o material. Assim uma combinação de alta resistência mecânica (> 1 GPa) e alta condutividade elétrica (mínimo de 70% IACS International Annealed Copper Standard) é necessária por parte destes materiais. No presente trabalho, foram desenvolvidos fios condutores para possível utilização em magnetos pulsados. O cobre e a liga nióbio-titânio foram escolhidos por possuírem boa condutividade elétrica e boa resistência mecânica, respectivamente; além de serem imiscíveis na temperatura ambiente. Inicialmente foram utilizados fios de cobre puro e Cu/NbTi, os quais foram convertidos em fios por trefilação. Após o processamento, os fios foram introduzidos em tarugos de cobre OFHC (Oxigen Free High Conductivity) e reprocessados. Foram produzidos 2 compósitos variando os tratamentos térmicos. Os compósitos obtiveram uma satisfatória interação matriz/filamento, o que melhor combinou propriedades mecânicas e elétricas foi o que atingiu limite de resistência de 547,8 MPa e condutividade 85,98% IACS.

Oct 30, 2017

By Eduardo Montenegro

Apesar da relevância e interesse do tema de gerenciamento de alarmes na comunidade técnica industrial, observa-se que poucas empresas têm, de fato, implantado e conseguido extrair melhores resultados na eficiência e segurança operacional de suas plantas. O presente trabalho visa, a partir das experiências dos autores em implantação e acompanhamento de vários sistemas de gerenciamento de alarmes na indústria, discutir os principais motivos pelos quais estes sistemas falham em conseguir índices melhores em operação, monitoramento e gestão de alarmes. Além disso, propõe-se neste trabalho que estratégias, práticas e ferramentas sejam adotadas para que se consiga o máximo de benefício operacional ao se implantar e manter tais sistemas.

Aug 16, 2017

By E. D. Gardner

This paper is one of a series on milling methods being published by the United States Bureau of Mines. Atlanta is in Elmore County, Idaho, about 80 miles from the railroad at Mountain Home, Idaho. The concentrator is at an elevation of, 6,000 feet and located in a timbered, well-watered region of relatively heavy snowfall. The snow, however, does not seriously affect local operations. The track road to Mountain Home, which passes over a mountain range, is closed each winter from about November 1 to June 15. During this period concentrates are stored and bullion is shipped by airplane. Power is generated by a Diesel engine and by an auxiliary hydroelectric plant. Gold is the principal metal produced; the or also contains an able quantity of silver.

Jan 1, 1935

By J H. Zietsman

The transition to more sustainable metal production is receiving much attention at present, and the iron and steel industry is at the centre of the conversation. New, more environmentally friendly production technologies, such as direct reduced iron (DRI) smelting furnaces, need to be developed in a short period of time. This necessitates increased use of computational modelling that incorporates more accurate material descriptions. The combination of large-scale multiphysics models of high-temperature processes with CALPHAD material descriptions leads to infeasible computation times. This can be resolved with the previously reported RapidThermo framework, which has been demonstrated to make equilibrium calculations orders of magnitude faster, within controllable limits of accuracy. In this paper, we explain how further material properties, which are important to modelling hightemperature reactors, can be added to the RapidThermo framework. This can improve the accuracy and usefulness of process and multiphysics models in the development of new technologies, which can significantly accelerate development cycles.

Aug 21, 2024

By F. E. Pawlek

Copper concentrates can be comminuted in an attritor within a very short time to a particle size of 1 - 0.1 um. Addition of sodium hydroxide enhances commninution. The concentrates, suspended only in water, can be completely dissolved under oxygen over pressure and temperatures ranging from 120 - 180°C (248 - 356°F), because the surface area of the concentrate has been significantly increased by the ultra fine grinding. Addi¬tion of a small amount of silver ions to leach liquor containing sulfuric acid acted as a catalyst for the dissolution of chalcopyrite, because of the formation of local elements on the surface. The addition of C1- ions was also catalytically very effective. With this method it is possible to completely dissolve the copper contained in chalcopyrite concentrates after ultra fine grinding within 30 min at 110°C (230°F) under an oxygen partial pressure of 1 atm (14 psig). Several flowsheets demonstrate the industrial feasibility.

Jan 1, 1976

By Nathan Ferdinands

Outline Overview of Site and Partners ?MeanduMine ?Thiess?GroundProbe Technology ?Work Area Monitor (WAM) ?Software control ?Alarms MeanduMine King2East pit failures ?Background, and Northern Failure ?Southern Failure Recovery and conclusion

Nov 1, 2011

By André Gauthier

"Los diferentes trabajos de prospección y exploración efectuados desde 1995 por Cambior Perú S.A. y Cía. Minera Kori Pampa S.A. en la región de Huamachuco, descubrieron los yacimientos auríferos La Arena y Virgen. En ese sentido, el presente texto describe la exploración del yacimiento minero La Arena -Virgen, la cual se ubica en la base de las rocas sedimentarias de la formación Chimú, mientras que el yacimiento Virgen se ubica enun nivel más alto, pero en la misma formación. En La Arena se ha reconocido un pórfido de cobre-oro en profundidad dentro de los primeros 350 metros, el cual aún no ha sido explorado en su integridad. Finalmente, ambos yacimientos presentan varias anomalías y zonas potenciales que aún falta explorar. "

Apr 26, 1999