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By R. Hurman Eric

The electrode in a slag-resistance electric furnace is the central factor in the design and operation of the furnace by its role of conveying the smelting power, i.e. heat needed for the operation. The control parameters are the size and positioning in the slag bath which are defined by slag resistivity, furnace resistance, cell constant and power input sequence all of which are closely interrelated. The flow of heat generated by the electrode current determines the energy distributions and thus the furnace dimensions. Heat flow models concerning vertical, horizontal and combined two-dimensional flows are discussed. All these considerations are based on the experimentally determined slag properties such as its resistivity.

Jan 1, 1995

By L. L. Damon

A geochemical study of cyanide neutralization processes was conducted at Brohm Mining Corporation to gain a better understanding of the leach pad behavior and to develop a simplified procedure to quantify the attainment of compliance with permitted cyanide neutralization criteria. Such attainment is a prerequisite for off-loading spent ore from the leach pad at the "load/unload" gold heap leach operation. The geochemical study program consisted of size fraction analyses and weak acid dissociable (wad) cyanide analyses for various sections of the spent ore from the actual leach pad. Further testwork included size fraction analyses and wad cyanide analyses on the ore from four 29 foot laboratory test columns which were leached and neutralized with different neutralization treatments in parallel with an actual active leach pad. Wad cyanide was analyzed daily on the neutralizing columns and various parameters were monitored weekly on the influents and effluents during the leach cycle and neutralization period. A comparison was made of neutralized effluent chemistry and porewater extraction fluids, as well as an analysis of the selective adsorption of cyanide on various particle size fractions.

Jan 1, 1992

By Bruce K. McKnight

"The new H-W orebody was evaluated by considering its production at three technically feasible rates. Capital and operating costs were estimated f or each rate and production sequences were established using mining cutoff limits generated by an ore value algorithm. The viability of the project was then examined by conducting economic and financial analyses of each of the three production cases under various world economic scenarios. These analyses employing standard profitability measures demonstrated all three cases would be economically viable; the production case which maximized the Net Present Value of the project was the one selected for development and production.IntroductionWestmin Resources Limited and its predecessor company, Western Mines Ltd., has been continuously carrying out mining operations near Myra Falls in Central Vancouver Island since December 1966. The mining operation, whose current production rate is approximately 830 tonnes / day (t/d), based on ore derived from the Myra and Lynx Mines, produces copper, lead and zinc concentrates which contain significant quantities of gold and silver in addition to the base metals.In the late 1970s, with Lynx and Myra ore reserves slipping to unacceptably low levels, a major increase in mine-site exploration was initiated, with outside geological staff brought in to complement the efforts of the mine's geological staff. By the end of 1979, this program had resulted in the discovery of a significant new orebody on a deeper horizon some 300 metres below the one which hosts the Lynx and Myra deposits. Throughout the period 1980-1982, major drilling was carried out to evaluate the new H-W deposit and by the end of 1982, drill-indicated mineral inventory for the deposit compared with Myra, Lynx and Price ore reserves was as shown in Table I. During this same three-year period, a major development and evaluation program was underway comprising environmental monitoring and control programs, shaft sinking test mining, bulk sampling and mill testing, rock mechanics studies and preparation of the Stage I and II reports for the multidisciplinary Environmental Land Use Committee (ELUC).As a result of the preliminary engineering work and exploration drilling, it became rapidly apparent that the H-W deposit could support a considerably higher production rate than the current one. Accordingly, engineering studies including scheduling of development and production as well as capital and operating cost estimates, were focused on three possible production rates: 1350, 1800 and 2700 t/d. Our task was to select the optimum one of these three rates."

Jan 1, 1987

By Kamran Esmaieli

Open Pit Mining Through Underground Voids: Challenges Main Challenges/Hazards: Unexpected collapse of the pit floor and/or pit walls; The loss of equipment and/or people into underground voids; Loss of explosives from blast holes that broken through into the underground voids. How to address these challenges? An important step that must be integrated into mine planning and design is the accurate detection and delineation of underground voids. (i.e. probe drilling, Geophysical techniques, laser scanning,?); Leaving a pillar of adequate thickness between the working bench and the underground voids; Backfilling the underground voids from surface using vertical or inclined raises; Monitoring the working locations (pit floor and pit slopes) to detect movements.

May 1, 2013

By W. E. MacDonald

This paper relates the story of 100 years of mining in the Harbour Seam at the Princess Colliery, Sydney Mines, Nova Scotia. Several interesting anecdotes are included along with the discussion of the evolution of coal mining methods in the area. Finally, some of the recently introduced equipment at Princess Colliery is described, and prospects for the future of the industry are outlined.

Jan 1, 1968

By Mustafa Kumral, Yu Cheng Yang, Zhixuan Shao, Young Bin Moon

Since the discoveries of favorable deposits are becoming increasingly difficult, mining operations shift to lower grade and deeper deposits. The viability of these operations is sensitive to many factors, such as commodity prices and operating costs. Given that a mining corporation has no power to set prices, the focus is directed on minimizing the operating costs. Underground mining operations require a network infrastructure, including shaft, ramps, declines, levels, cross-cuts, raises, winzes, and adit. The design of this network is a costly process. As such, it has a significant potential to reduce development and haulage costs. Furthermore, network design is a continuous process along with development, production, and maintenance throughout mine life. Under the constraints of the turning radius, the gradient, and the obstacle avoidance for haulage network of underground mines, this paper first demonstrates network design and optimization approaches using Dubins path combined with the Hierarchical Density-Based Spatial Clustering of Applications with Noise (HDBSCAN) algorithm. A threshold-based model is developed, providing viable solutions to the network design when the number of declines is high. Furthermore, a three-dimensional Rapid-exploring Random Tree (RRT) algorithm combined with Dubins path is employed as a heuristic solver for obstacle avoidance purposes in the network. Various case studies are conducted to show the applicability of the proposed methods.

May 24, 2023

By Prashant Dixit, Akhil Singh, Asim Kumar Mukherjee, Sudipta Patra, Veerendra Singh

Phosphorous is an undesired element present in iron ore used in the steel making process. It leads to an increase in overall production cost as well as deteriorated steel quality. The desired phosphorus content in iron ores used in steel making is < 0.1%. Numerous beneficiation studies are mentioned in the literature; however, there is no commercial scale technology established to beneficiate high phosphorous iron. The major phosphorous bearing minerals are apatite (Ca5(PO4)(Cl/F/OH), wavellite (Al3(PO4)2(OH)3·5(H2O)), senegalite (Al2(PO4)(OH)3(H2O), barrandite ((Fe,Al)PO4·2H2O), etc. Ultrafine grinding is required to liberate phosphorous minerals from iron ore minerals and subsequently subject it to flotation, acid leaching, and bioprocessing. The selective flotation of iron ore could successfully reduce the phosphorous content from 0.82% to < 0.20% with the combination of grinding, magnetic separation, and carbothermic reduction. Acid leaching processes are also able to remove ~80% (0.85%→0.16%) of phosphorus; however, these are relatively costly and complex processes. The mechanism of bio-extraction for phosphorous removal is reported as one of the most successful processes. This process is capable of removing more than 80% of the total phosphorous and significantly reducing the phosphorous content from 1.06% to 0.16%. The main disadvantage of this process is that it occurs at a much slower pace. In today’s scenario, ultrafine grinding followed by froth flotation seems to be the most feasible solution for the beneficiation of high phosphorous iron ore in which the concentrate obtained can be utilized for pellet making and ultimately used for steel making processes. Development of additives for leaching, roasting, and bioprocessing can be explored further to make these processes more effective and economically viable.

May 28, 2024

By V. P. Mehrotra, D. W. Fuerstenau, A. -Z. M. Abouzeid

The use of pulverized coal for electric power generation results in the production of vast amounts of fly ash. One potential use for waste fly ash is the production of pellets for lightweight aggregates. This paper is concerned with the role of the physical and chemical characteristics of two different fly ashes in governing their agglomeration or pelletization behavior and their strength characteristics. In batch balling experiments, fly ash pellet growth was found to be extremely sensitive to the amount of moisture added. One ash (Mohave) exhibits marked pozzolanic activity whereas the other (Jim Bridger) does not. The pozzolanic activity has a very pronounced effect on pellet growth kinetics, moisture requirements, and the effect of various additives on growth kinetics. Slow drying under ambient conditions produces strong pellets from Mohave ash whereas Jim Bridger ash pellets lacking in pozzolanic activity are weak. Rapid drying at high temperatures results in weak pellets because water necessary for hardening is driven out of the pellet. Steam curing enhances pellet strength. Locked-cycle pelletizing experiments exhibit expected oscillation in pellet production rates and attendant fluctuations in pellet green strength.

Jan 1, 2004

By Rak-lun Choi

Plasma-induced damage of InGaN/GaN multiple quantum well (MQW) light-emitting diodes (LEDs) has been studied in terms of forward turn-on and reverse breakdown voltages, together with etch rate and surface morphology. The physical degradation of sidewall along with rough surface morphology of n-GaN caused by increased ion scattering induced the deterioration of the forward and reverse voltages. It was found that the turn-on voltage is sensitive to the surface roughness of the etched n-GaN and the breakdown voltage is strongly affected by the sidewall contamination. Annealing under nitrogen after the mesa etching improved the electrical properties of the InGaN/GaN MQW LEDs. Efficient blue light-emitting diodes (LEDs) were fabricated using InGaN/GaN triangular MQWs. The LEDs with triangular QWs showed a lower operation voltage and 2.4 times higher light output power than those with the rectangular MQW LEDs at 20 mA and 20 °C. The intensity of electroluminescence (EL) at 20 mA was almost independent of ambient temperature in the triangular QW LED, but decreased substantially in the rectangular one.

Jan 1, 2003

By Miroslaw M. Hajdasinski

A project&apos;s rate of return (ROR) [The list of all the acronyms used in his text is provided at its end.], be it an internal or external one, usually needs to be approximated. The success and efficiency of an approximation procedure depend on the quality of the initiating parameters such as bounds or seed values (guesses). Current approximation procedures commonly use bounds and guesses dictated by intuition rather then by mathematical consideration. The paper presents three ROR-bounding and six ROR-guessing approaches and examines their suitability on the examples of the typical project cash flow patterns.

Jan 1, 1996

By Rafael Henrique Alves Gomes

A automação em processos industriais agrega qualidade, padronização e segurança aos produtos e pessoas envolvidas. Entretanto, as demandas de mercado, custos agregados e a concorrência exigem melhorias que podem ser alcançadas através de métodos de otimização. Este artigo apresenta algumas metodologias e ferramentas para otimização de processos industriais que visam desvincular a obrigatoriedade de que Técnicas de Controle Avançado em métodos de otimização são a única solução capaz de oferecer resultados satisfatórios para aumento de produtividade. Os recursos expostos abordam a gestão de malhas de controle, gestão de alarmes e o cálculo do indicador global de eficiência, o OEE.

Aug 17, 2017

By William R. Wayment, David E. Nicholson

A modified percolation - rate test is proposed for use in determining flow rates through hydraulic backfill ; in contrast to the conventional test , a percolation- rate versus void - ratio relationship is established . requirements and a detailed test procedure are described . Equipment Results of a conventional test are compared with those of the proposed modified test . The proposed modified test method yields more accurate , realistic , and usable percolation- rate ( permeability ) data . The significance of obtaining accurate percolation rates for use in analyzing waterflow through hydraulic backfill is discussed .

Jan 1, 1964

By Robert M. Stevens

INTRODUCTION Truck haulage of muck in underground mining operations has been in use around the world for many years. From the late 1.950s into the early 1970s, haulage by means of load-haul-dump (LHD) units challenged haulage by means of trucks, and, to a large degree, LHD units dominated the trackless concept of moving mate¬rial underground. However, beginning in 1975, the emphasis began to shift back to the use of trucks, with LHD units assuming the secondary role of loading the trucks. Over the years, several manufacturers have been offering trucks with capacities ranging from 4.5 to 45.4 t (5 to 50 st) and with features that specifically address the constraints of underground operation. TRUCK TYPES Three different types of trucks are available for use underground, namely the tip dumpers, telescoping dumpers, and push-plate dumpers. The following para¬graphs describe each of these three types. Tip Dumpers Tip dumpers are designed to lift the truck box, using gravity to dump the load out the rear of the box. The primary application of these trucks is in the haulage of muck to the surface. However, these trucks also may be utilized underground, if a chamber is provided to accommodate the raised truck box at the dumping point. Fig. 1 illustrates a four-wheel drive truck with a 10.0-t (11-st) capacity; this truck is only 1.9 m (6.25 ft) wide and is designed specifically to follow narrow and winding vein courses. Fig. 2 illustrates a two-wheel drive tip dumper with a 24.5-t (27-st) capacity; this truck operates on 12% grades with firm dry surfaces and in modes both loaded-up and loaded¬down. Telescoping Dumpers Telescoping dumpers specifically address the constraints imposed by low back heights, and they represent an optimization of compressed envelope size with maximum payload capacity. Figs. 3 and 4 illus¬trate a typical telescoping dumper with a capacity of 18.1 t (20 st). Fig. 3 shows the box in position for carrying the load, and Fig. 4 shows the same truck with the box in the full-dumping position. Fig. 5 illustrates the loading and dumping cycles. Fig. 6 illustrates an approximation of how an LHD unit with an eject-o-dump (EOD) bucket would be used to load over the rear of this type of truck. Fig. 6 shows a low-profile telescoping truck in the first stage of loading, with a 6.8-t (7.5-st) LHD unit equipped with an EOD bucket. A loader with a smaller capacity and a narrower bucket would allow the bucket to fit inside the truck box and would achieve an even lower loading height than that illustrated. Gen erally, an LHD unit equipped with an EOD bucket and teamed with a telescoping dump truck can be used with a lower back height than could any other front-end loader and truck team. Push-Plate Dumpers Push-plate dumpers are similar to telescoping Bump¬ers, except that they do not have the two-stage box. Instead, push-plate dumpers utilize a single push plate to discharge the load out the rear of the box. Gen erally, these units are limited to payload capacities of about 9 t (10 st). Fig. 7 illustrates a typical push-plate dumper.

Jan 1, 1982

By Jonathan Ruiz Lizardo, Met-Chem Canada Inc., Flavio Ccuno, Constante Umipig, Ewald Pengel, José Ruiz

"Cerro de Maimón is located in the Dominican Republic on the island of Hispaniola approximately 75 kilometers northwest of the capital city, Santo Domingo. The processing facility consisted of two separate processing plants for oxide and sulphide ores. The oxide plant processed oxide ore bearing gold and silver ore using cyanide leaching and Merrill Crowe processes, while the sulphide plant produced a copper concentrate using conventional flotation. Cormidom is a commendatory example how mineral processing facilities can co-exist in balance with the environment. In 2014, natural occurring copper oxide contamination with finer grained copper-zinc sulphide mineralisation was expected to dominate the sulphide ore body. In anticipation Cormidom contacted the original plant designer Met-Chem to assist in overcoming this challenge. Test work indicated that increased flotation time and subsequent very fine grinding were required. Met-Chem provided the detailed engineering and Cormidom proceeded with the expansion project internally. Currently Cormidom has processed the sulphide ore successfully by implementing flotation modifications. This paper describes the history of Cormidom, test work on the “new” ore body, modification in process design in the Cu-Zn sulphide flotation circuit, construction and implementation.INTRODUCTIONCorporación Minera Dominicana (CORMIDOM) was a wholly owned subsidiary of GlobeStar Mining Corporation (a Canadian based minerals exploration company) with extensive exploration of base and precious metals in the Dominican Republic. In 2007-2008 CORMIDOM constructed the Cerro de Maimom project. The company was subsequently sold and purchased by Perilya Limited from Australia in 2013. Cerro de Maimón is located in the Dominican Republic on the island of Hispaniola approximately 75 kilometers northwest of the capital city, Santo Domingo. It is near the town of Maimón in Monsenor, Nouel Province (see Figure 1)."

Jan 1, 2016

By M Orunesu Preiata

The Odysseus Project is part of the high-grade Cosmos Nickel Complex that lies 30 km north of Leinster. The Odysseus definitive feasibility study (DFS) was approved by the Western Areas’ board in October 2018. Early works commenced in January 2019 with rehabilitation of the existing underground infrastructure. In June 2022 Western Areas was acquired by IGO Ltd. The project is now well advanced to meet its target of first concentrate. The project included the construction of a haulage shaft. The design of the hoisting equipment and the shaft barrel evolved from the initial DFS design stage to the final execution, as the data were made available from the initial investigation to the data gathered during execution (although this did not change from its initial concept). The design philosophy for the haulage shaft incorporated, from the beginning a multidisciplinary approach with inputs from three main areas involved in such projects, namely excavation techniques, geotechnical assessments, and infrastructure construction. This interaction is a fundamental component for the success of such a critical project. In fact, each of these three areas influences each other in a cyclical manner, triggering a continuous review of the project inputs and outputs, while maintaining the original project goals: the design of an infrastructure able to deliver the desired throughput. The throughput dictates the infrastructure that needs to be built, which in turn controls the size of the shaft. The key assumption applied to this is that the rock mass can accommodate the excavation void, and the excavation technique with its tolerances and limits that ultimately need to be verified back with the initial assumptions used for the infrastructure design. The aim of the paper is to present a case study of the experience gained with the Odysseus hoisting shaft and to propose a possible logic path for similar projects elsewhere.

Mar 29, 2023

By G. F. Loughlin

THE matter of grading Indiana oolitic limestone has been under a cooperative study by the Supervising Architect&apos;s office, the U. S. Geological Survey, the Bureau of Standards, and the former Indiana Limestone Quarrymen&apos;s Association. As the criteria for grading are necessarily based on a number of geologic and related factors of which those quarrying and using the stone had only imperfect appreciation, the first part of the report is a very elementary account of the origin, structure, and the chemical and physical properties of tie stone, and their relations to durability and utilization, and serves as a foundation for the second part, which discusses grading and pro- poses limits for grades established by the quamymen. Salient features of Part I of a report that has been prepared are the variations in uniformity of stone due to cross bedding, and local uncomformities; the relative prominence of weathering effects on the coarser uneven grained surfaces, and its apparent absence on fine, uniform grained surfaces, although the amount of weathering is the same on each; the attributing "crow feet" (stylolites) to solution under pressure, and the explanation that, whereas the thinnest "crow feet" have no noteworthy effect on weathering quality or strength, the thicker ones are likely to weather out rapidly and to promote splitting; the influence of fracturing on the oxidation of the original gray or "blue" to buff color above the ground water level; the interpretation of chemical analyses and the pointing out that both the gray and buff colors are due mainly to organic

Jan 1, 1929

By Liangying Wen, Feng Xia, Chenguang Bai

"The situation of the Ti-V-Magnetite samples reduced with microwave has been investigated in laboratory. Firstly, the paper focuses on the heating behaviors of vanadium-titanium magnetite and characteristics of carbothermic reduction of V-Ti-magnetite in the microwave field. The effect of concentrate's size, quality on heating behaviors and reduction processes were researched. Results show that microwave heating may be a new heating resource replace of carbonic combustion reaction in reducing reaction. When the allocation of carbon is (16.7-30)%, carbothermic reduction of V-Ti-magnetite in the microwave field can proceed; with the increasing of carbon mixed, the metallization rate increases; and Fe, V can be reduced from their oxides in the microwave field; Titanic low oxide can be reduced from TiO2.1. IntroductionThe resource of Ti-V-Magnetite is abundant in the western area of Panzhihua in China, so far a mineral deposit of 4.64 billion tons have been proved up, it contains 14.75 million tons of V2O S which accounted for 87% of the vanadium and 5.93 hundred million tons of TiO2 accounted for 94% of the titanium resource respectively in China. The previous study proved that the major composition of mineral of the Ti-V-magnetite are Ti-magnetite, limonite, iron spinel, magnesium spinel etc, and the main elements of the Ti-V-magnetite in this area are Fe, Ti, V, Cr, Co, Ni, Ga, Sc etc[1] Due to the restrict of the BF-BOF process technical, during the smelting of the iron, the level of extracting the vanadium, titanium as well as other metal elements is limited. This results serious wasting of resources. To develop a new reduction process of Ti-V-magnetite is on the agenda, the microwave assistant reduction could meets this need, based on its characteristic of easy controlling of heating rate. To make use of the microwave energy to substitute the released heat sources of carbon combustion with air, use the solid phase state reduction at a relative lower temperature, make the beneficial element in Ti-V-magnetite transferred into the metal phase, then separated from the impurity. It is well worth to point out that once the microwave based reduction method has its industrial scale, it will take an outstanding position by its less release of carbon dioxide. This new environment-friendly process will play a vital role in the development of social industry and economy."

Jan 1, 2008

By J. S. Dunning

The objective of this research by the U.S. Bureau of Mines was to determine the effects of AI additions on the sulfidation resistance of Fe-Cr-Ni alloys. A series of Fe-Cr-Ni alloys with and without -additions of 4 pet AI were tested in a wet S vapor atmosphere at 677 C. A study of the morphology and composition of corrosion scales indicated a different corrosion mechanism for AI-free alloys compared with AI-containing alloys. Aluminum-containing alloys formed a compact, tightly adherent layer at the metal-scale interface that reduced corrosion rates by a factor of 3 to 10 compared with that of AI-free alloys. The thin, adherent AI-containing scale limited inward diffusion of 0 and S to the base metal and outward diffusion of Ni from the base metal. Aluminum-containing alloys formed a three-layer scale in oxidizing-S environments, while AI-free alloys formed a less protective two-layer scale.

Jan 1, 1989

By D. N. Hillhouse

The economics of exploration target selection can be measured ultimately only against a company&apos;s success at developing mines. In the following brief history of the mine acquisitions of one company, Placer Development Limited, I try to identify the principal targeting parameters and the principal skills that came into play for each property and examine how these have changed with time. The process of target selection in exploration is directed: - first by corporate investment criteria which define objectives and acceptable levels of risk for pursuit of those objectives; - second by experience and skills which permit us to minimize risk; and - third by anticipation of future events relating to ore discoveries and changes in external risk factors.

Jan 1, 1984

By A. Bieg, M. Samson, Z. Bell, A. Zinsser, J. Schuyler

As the world progresses toward the renewable energy transition, the demand for minerals increases exponentially. According to the International Energy Agency (IEA) 2021 Net Zero by 2050 Report, critical mineral production needs to grow six times to combat climate change. It’s estimated that four to seven percent of global greenhouse gas (GHG) emissions come from the mining sector’s Scope 1 and 2 (direct and indirect) emissions. Including Scope 3 (upstream, downstream, and embedded) emissions, the sector accounts for 28% of global GHG emissions. In a typical mining operation, diesel fuel is the biggest source of direct GHG emissions, and haulage is often the main source of diesel emissions. Large haul trucks have been the industry standard for over 50 years and offer flexibility, relatively low capital cost (especially with equipment lease options), and guaranteed technology with known maintenance. The challenge will be to justify their continued use when there are more economical options that lead to significant reductions in GHG emissions. The purpose of this study is to compare five haulage options in terms of GHG emissions, using the methodology defined by the Greenhouse Gas Protocol Scopes 1, 2, and 3 (Category 2). Additionally, this analysis compares operating and capital costs associated with the five haulage options (emerging and proven technologies): 1) Diesel-Electric Haul Trucks, 2) Battery-Electric Haul Trucks, 3) Fuel Cell Haul Trucks, 4) Railveyor, and 5) Conveyor. This analysis looks at the emissions and costs associated with operating the equipment (fuel and electricity), the embedded emissions and costs associated with the construction and installation of the equipment itself, and the associated infrastructure (roads, powerlines, and rail).

Feb 1, 2023