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By D. R. Nagaraj

Secondary Ion Mass Spectroscopy (SIMS) was used to study adsorption of sulfide collectors such as modified thionocarbamates and thioureas, xanthate, dithiophosphate, and dithiophosphinate, on galena, chalcocite, chalcopyrite, and quartz under flotation related conditions. In the case of the adsorption of modified thiourea on chalcopyrite, chalcocite and Cu-activated quartz, and of dithiophosphinate on galena, SIMS measurements have provided direct evidence for the presence of metal-collector (1:1) complexes on surfaces. In the other systems, only the collector molecular ion and its fragments were detected. The distribution of adsorbed species on the surfaces was obtained by using SIMS in the imaging mode. On chalcopyrite, only the copper-collector complex was found; there was no evidence for iron-collector complex. In the case of quartz, adsorption of selective collectors was observed only after activation by copper ions.

Jan 1, 1996

By T. V. Johnson

The microstructural relationships in dolomitic fluxed taconite pellets were studied. The influence of basicity (in the range 0.75 to 2.1) and firing temperature (to 1340°C) on the grain structure, macrostructure, and mineralogical phase relationships are described. Extensive slag bonding of hematite grains begins at temperatures between 1220 and 1230°C, and results in fundamental changes in grain structure. Successive temperature increases result in little change in grain structure until 1340°C, when extensive coalescence of the hematite grains begins.' Increasing flux additions have little effect on grain structure but greatly influence pore character. The compressive strength decreases with increasing flux addition, increases with increasing firing temperature, and is related to the macrostructure of the pellet. The compositions of the slag phases are represented on the CaO-Fe2O3-SiO2 phase diagram, and the compositional path of slag development is described.

Jan 1, 1980

By Ren Xiangwen, Shi Xuefa, Shao Mingjuan, Ye Jun, Yang Yaomin, Li Bing

"The Mid-Atlantic Ridge (MAR), one of the archetypes of slow spreading ocean ridges, extends from the Arctic Mid-Ocean Ridge southward to the Bouvet triple junction making up a significant proportion (~ 40%) of the global oceanic ridge system. During the past few decades, many hydrothermal fields like TAG, Logatchev, Ashasze were discovered along the northern part of the MAR, whereas the southern part, which makes up one third of the ridge (6000km), shows little documentation of hydrothermal mineralization, except for three sites: Site 4°48! the Nibelungen Field, and Lilliput. During March to May 2011, following discovery of three new hydrothermal fields during the 2nd Leg of COMRA's 22 Cruise of the R/V DayangYihao, the 3rd and 4th Legs found another two high temperature hydrothermal fields (SMAR15°S, SMAR26°S), one low temperature field, and several fields with strong turbidity and temperature anomalies in the water column. In this study, we present a preliminarily study of the mineralogy and isotopic geochemistry of the sulfides from SMAR 15°S and SMAR26°S.SMAR 15°S is situated in a SE-NW offset depression of an axial neovolcanic ridge in the median valley, with water depth of about 2793m. In the water column around this field, strong turbidity and temperature anomalies were detected. Ten-meter tall venting chimneys, hydrothermal mounds, as well as a large amount of hydrothermal vent shrimp were also observed and recorded by ROV and deep-tow camera surveys. The samples collected from this field include sulfide chimney fragments, massive sulfides and basaltic rocks. Based on the major metal and the mineral assemblages, three types of sulfides have been identified: 1) Zn-Fe rich sulfides with abundant wurtzite and pyrite zoned fragments, 2) Cu-Fe rich sulfides with much isocubanite and pyrite assemblage, 3) Fe-rich sulfide with massive pyrite fragments. These indicate that this field has undergone at least three phases of mineralization during the venting history."

Sep 1, 2014

By M. J. Hrebar

In the summer of 1990, a study was conducted to document large tractor (i.e., Caterpillar Dl1N) utilization in surface coal mining. The tractors were found to be utilized as primary production machines and in combination systems with blast casting and draglines and blast casting and excavator/truck systems. In addition, dozers were used to prebench ahead of a primary dragline system. The study also established ranges and averages for Dl1N operating costs and mechanical availability. Based on simulated production of various tractor dozing applications, the potential for low cost coal stripping was suggested (Hrebar, 1991). A follow-up study, also funded by Caterpillar Inc., was conducted in the summer of 1991 to determine actual production rates in two dozer stripping applications. These actual production rates would then serve as a foundation for estimates of stripping costs. This paper presents the results of the studies in a contour and a cast application.

Jan 1, 1992

By William E. Bedal, Richard S. Kunter

Artech Recovery Systems, Inc has developed a low pressure and temperature chloride leach process called the "Caslumu1 Process" to extract metals from arsenical flue dusts and residues and fix the arsenic in an environmentally stable form as ferric arsenate (scorodite). The process was pilot tested at Hazen Research in an integrated plant including continuous recycle from August 1989 to October 1989 during which several tons of flue dust were processed. Based on this pilot program, the process was deemed technically feasible and produced commercially salable products. Residues from this pilot program were subjected to a long-term stability test jointly designed by Prl environmental services and the USEPA. The process, its versatility, and the nature of the products ls discussed in some detail.

Jan 1, 1992

By V. C. Lo

The major cost in comminution is energy consumption, which can be as high as 50 percent of the operating cost. Improvements in plant operations have resulted in up to a 15-percent reduction in energy usage (kwh/t). These improvements have been made through optimization of grinding efficiency and use of expert model-based control systems. Optimization involves the determination of the levels of the critical operating conditions that result in the most efficient breakage of ore in the mill. These optimal levels are identified through plant/laboratory testwork and computer simulation using advanced process models. Model-based expert control achieves the maximum performance from the grinding circuit by identifying the characteristics of the ore in the mill with an optimal on-line estimator. Using this information, the control system dynamically determines the operating point that will yield the optimal performance. Two industrial applications of grinding circuit optimization and model-based control are presented to demonstrate the power of this new technology.

Jan 1, 1995

By Song Xiaotian

In this paper the enviroment in which Tong Kuang Yu mine, China is developed is described. Geological and geomechanical environments which pose difficulties in the design and optimization of Block Caving are discussed. According to mine conditions, caving process simulation was carried out using Displacement Discontinuty Method and relationships between stress distribution .and undercut parameters were established in accordance with different undercut sequence. Based on simulation the influences of caving parameters on caving probability, drift instability and ore-draw control were analysed in order to optimize Block Caving Mining. On the basis of simulation and mathematical programming, the optimal sequence is proposed essential to satisfy the safety, production and other restrictions.

Jan 1, 1989

By Jian Liu

The dissolubility of a natural sphalerite (ZnS) in the entire pH range was theoretically calculated, and its practical dissolution in an aqueous solution at different pH values in an inert environment, together with its surface properties after dissolution, was fully investigated. The results of the investigation indicate that the total concentration of Zn (CZnT) decreases significantly with the increase of pH value, while the pH value is set below 8; however, it reverses when the pH value reaches 8. Such a tendency is similar to that of the theoretical calculations, although the experimental CZnT were much higher than those of the theoretical calculations. The X-ray photoelectron spectroscopy (XPS) of the sphalerite surface after its dissolution under alkaline solution shows that a polysulfide (Sn 2-) surface layer with a binding energy (BE) value of 162.96-163.25 eV is present on the surface, and the percentage of Sn 2- increases significantly with an increase in pH value; the undissolved and dissolved sphalerites under the acidic solution have a negligible difference in S2p peaks. The surface S/Zn ratio of all dissolved sphalerites shows a marked Zn enrichment and S deficiency. An atomic force microscope (AFM) view of the sphalerite surface, after its dissolution under the alkaline solution at a pH of 12, shows that the surface is significantly different in morphology from that of the undissolved one.

May 1, 2012

By James S. Browning

The Mineral Resources Institute of The University of Alabama conducted research on the removal of sulfur from coal using a combination of gravity concentration and flotation methods. The research utilized the gravity and centrifugal force capabilities of the Humphreys spiral to remove part of the pyritic sulfur and ash. Flotation of the Humphreys spiral coal concentrate removed additional sulfur and ash to yield products that conform to Federal air quality standards for sulfur oxide emissions. The clean coal products recovered by the combined process contained 7.7 to 8.0 percent ash, 0.12 to 0.16 percent pyritic sulfur, and 0.78 to 0.96 percent total sulfur. Pyritic sulfur rejection by the process was about 95 percent. In addition to obtaining good recoveries of high quality coal the tests demonstrated that the pyrite in the wastes could be isolated as enriched flotation products by the combined gravity - flotation apporach. Pyrite concentrates analyzing 25 to 33 percent sulfur were recovered. Potential benefits of the pyrite flotation step are recovery of a product of possible market value and the elimination of the pyrite from the waste ash which could be a potential acid water problem when impounded.

Jan 1, 1981

By D. McCarthy

This paper discusses the process involved in developing an optimum method of treating and removing heavy metals from water that have leached out from the native rock -prior to discharge back into the environment. Also designed into the system is a manner to stabilize the metals removed as a precipitate, so that they can be disposed of as a non-hazardous waste.

Jan 1, 1992

By V. A. Temeng, M. Owusu-Tweneboah, K. Awuah-Offei

The mining industry has long recognized the value of dispatch systems in open pit mines as they reduce load and haul costs. Over the years, researchers have proposed many dispatch systems with various limitations and advantages. The simplest dispatch algorithms are the so called 1-truck-for-N-shovels dispatch strategy. These algorithms are limited by the fact that their objective functions do not consider all the objectives of a mine and cannot be applied to all possible truck-shovel configurations. They are also myopic in nature. However, they are simple and computationally efficient and do not require occasional updates of the upper stage problem as required in multi-stage dispatch algorithms. In this work, an agent-based truck dispatch algorithm that conceptualizes trucks as intelligent agents that make autonomous dispatching decisions to maximize their utility is proposed. The advantages of this algorithm includes utility functions that encapsulate all of management’s objectives and agent’s with broad situational awareness. They are also more suitable for autonomous trucks. We evaluate the new algorithm against a simple 1-truck-for-N-shovels dispatch strategies using discrete event simulation. The simulation results show that the new utility function has significant advantages over 1-truck-for-N-shovels inspired utility functions. Future work will incorporate adaptive behavior into the model via reinforcement learning algorithm. INTRODUCTION In an attempt to optimize truck shovel operations in open pit mines in order to reduce the cost of haulage operation, which according to (Alarie and Gamache, 2002) is estimated to be about 50-60% of the total cost of mining, several effective and efficient strategies have been developed. Optimizing truck haulage systems in an open pit mine is one of the greatest challenges of mining engineering and has been the subject of many research projects. It is important that haulage systems are designed to be efficient, in order to minimise haulage cost, improve profitability and increase the total mine value. Although optimizing the number of trucks required in the operation of open pit mines can help reduce the cost, an effective and efficient truck dispatching system add value by ensuring that the available trucks are used efficiently. With truck dispatching systems, the trucks are normally dispatched between the crusher and dumping station (e.g. waste dumps and stockpiles), and the shovels in order to maximize the total output, obtain grades targets, reduce fuel consumptions and other objectives. Truck dispatching, which can have one or more objectives, is typically subjected to certain operational constraints such as truck and shovel capacities, empty and loaded trucks speed, among others. The problems associated with truck dispatching was first mentioned by Dantzig and Ramser (1959) after they made an attempt to determine the optimum routes of a fleet of delivery trucks between bulk terminals and a service stations. The problem occurs in several industrial systems besides mining (Alarie and Gamache, 2002; Gendreau et al., 2006; Rego and Roucariol, 1995). The dispatching problem, also referred in literature as the vehicle routing problem, has seen a number of modifications and extensions with Bertsimas and Ryzin (1991) presenting a dynamic and stochastic vehicle routing problem, and Ralphs et al. (2003) also adding to the original concept, the concept of vehicle capacity routing.

Jan 1, 2019

Beneath some of New York?s most iconic buildings ? The Met Life Building, the Helmsley Building, the Waldorf Astoria ? crews are busily at work on the Metropolitan Transportation Authority?s long-awaited East Side Access (ESA) project. In fact, it is 14 floors beneath the famed Grand Central Station where one of the centerpieces of the project, the new Long Island Railroad (LIRR) station terminal, is being blasted and carved into shape. When completed in 2016, the $7.3-billion ESA project will increase LIRR?s capacity into Manhattan and significantly relieve congestion at Penn Station. Currently, 37 LIRR trains per rush hour roll into the crowded Penn Station where many riders must then transfer to subway trains to complete their commute. When completed, the ESA tunnels will bring an estimated 160,000 riders directly to Grand Central Station, saving those riders 30 to 40 minutes. Studies have found that more people work within walking distance of Grand Central than Penn Station. ?The benefits of the project are tremendous,? MTA Capital Construction President Michael Horodniceanu told more than 340 industry professionals attending the UCA of SME?s George A. Fox Conference in New York on Jan. 26. ?The ESA is the first expansion of the LIRR in 100 years. It will increase the East River tunnel capacity by 50 percent and will help support job growth around Grand Central.?

Jan 3, 2010

By R. V. Ramani, K. V. Raj, S. Bandopadhyay

The air flow problems in openpit mines are complex. Computational fluid dynamics (CFD) models can provide detailed information regarding air flow pattern, velocity distribution, temperature, and pollutant concentration in an enclosed domain of an openpit mine. A range of turbulent models can be selected with varying complexity and accuracy. Pollutant transport models, however, differ in their assumptions and structure as well as in the algorithms they use. As a result, predictions vary from model to model. This paper presents a study of pollutant transport in an actual openpit mine under a stable boundary layer. The objective was to test two turbulence models using similar geometry and the same input conditions and model constants. Measured data were used to compare the results of the two CFD models, namely, the kappa-epsilon (к-є) model and the Large Eddy Simulation model. Despite the complex synoptic situations, different meteorological input data and fast-changing conditions, the simulation results from both the models were in good agreement regarding the dispersion of pollutants.

Jan 1, 2015

By W. R. McDonald

The U.S. Department of the Interior, Bureau of Mines, conducted field tests on acidic copper tailing as part of its program to devise, improve, and demonstrate technology for stabilizing mining and mineral processing wastes. Results will be presented from successful 1/8-acre and 1-1/2-acre demonstration revegetation plots established in 1973 and 1974 on an abandoned copper tailing pond located on public land adjacent to Holden Village, Wash. The tailing was neutralized with treatments of either dolomitic lime or limerock and fertilized with processed sewage sludge and/or commercial fertilizer. Plant growth covering 60 percent of the surface was achieved on both test plots. Regar brome, Tegmar intermediate wheatgrass, and tall wheatgrass provided the best plant growth and surface coverage. In neutralizing the tailing, the target pH of 6.8 was not achieved; however, good plant growth occurred in areas where the pH ranged from 2.9 to 5.8.

Jan 1, 1979

By Guy D. Bruno

Through the remainder of this century, world consumption of fluorine per ton of primary aluminum produced will continue to be substantially reduced. Growth of the primary industry will offset some of the unit consumption, but demand for new fluorine sources will decline sharply. Continued application of dry fume scrubbing systems will be the most significant factor in reducing demand.

Jan 1, 1978

By Joshua Cole, Joshua Sovechles, Christian Cardoso, Guillermo Bermudez, Martta Hirsi, Joshua Dettamanti, Rabia Abbasi

The implementation of technological advancements in flotation is key to optimize performance in mining operations. Consequently, flotation cell’s performance is highly dependent on the effectiveness of the mixing mechanism. A more efficient flotation mixing mechanism is likely to improve metallurgical performance and optimize energy consumption, which is the motivation for Metso’s journey to develop the latest iteration of FloatForce®. Looking to test the new design at plant scale, Metso approached the Kennecott Copperton concentrator, which is continuously looking for different venues to improve metallurgical performance. In this context, a test campaign was conducted to implement this new flotation mixing mechanism in their rougher circuit during 2024. The industrial trial consisted of several sampling campaigns assessing different operational parameters for comparison purposes around a 300m3 flotation cell. The effect of the new flotation mixing mechanism on the cell’s power draw was also studied. The results of this trial at Kennecott are presented in this paper. Overall new flotation mixing mechanism, FloatForce+ was seen to perform as well as the original FloatForce.

Feb 1, 2025

By Dongjie Zhang, Shuxin Liu, Jianduo Wang

Broken rock mass and unreasonable stope structure parameters can cause excessive ore loss and dilution in sublevel caving; this is the main problem faced by caving mining in recent years. This paper proposes a stope structure parameter optimization method suitable for steeply inclined medium-thick broken ore bodies and evaluates the reliability and effectiveness through case studies. To solve the problem of large ore loss and dilution in the high-end wall sublevel caving method of Xilinhot fluorite mine, it is necessary to select proper stope structure parameters. Based on the theory of random media, an end-wall ore drawing experiment was carried out, and the bulk flow parameters needed to optimization of stope structure parameters were determined. In the experiment, it was found the draw-out body of high-end wall ore drawing showed a fine top and a thick bottom; the granular media had good fluidity. The reasonable caving step is determined to be 1.2 m instead of the 1.6 m originally used. Through the optimization experiment of the mining route position along the vein, the study found that the best route position is different with the ore body inclination. When the inclination angle of the ore body was 90°, the reasonable route was located in the center of the ore body. When the inclination angle of the ore body was between 85° and 90°, the route moved from the center of the ore body to the footwall at a rate of 22.5%. When the inclination angle of the ore body was between 80° and 85°, the route moved to the footwall at a rate of 54.8%. When the inclination angle of the ore body is not greater than 80°, the route should be arranged on the boundary of the footwall. Field application results showed the dilution rate reduced by 7.66% and the recovery rate increased by 7.31%. Field test results verify the effectiveness and applicability of the optimized stope structure, which corroborates the effectiveness and applicability of the optimized stope structure.

Mar 10, 2022

By John B. Goddard

Crystallization of ammonium paratungstate (APT) is frequently the last effective purification step in producing high-purity tungsten. However, crystallizer mother liquors are often several times higher in tungsten than predicted by the solubility of APT. The formation of heteropoly anions, particularly those containing phosphorus and silicon, is largely responsible. Solubility of tungsten in APT mother liquor can be linearly correlated with the concentration of these and other impurities. The problem can be overcome by direct treatment of the crystallizer feed solution with alum. By appropriate treatment, the aluminum hydroxide flocculates and is easily filtered, resulting in a purified low-aluminum crystallizer feed from which high APT yields can be attained.

Jan 1, 1984

By B. A. Firth

The presence of misplaced ultra-fine particles has been shown to decrease the separation efficiency of unit operations used in coal preparation. Although the classification of fine coal was considered to be adequate for the needs of the coal industry during the 1970's and 1980's, it has become apparent that further improvements in the yield/ash/moisture relationship achieved by coal preparation plants will require increased efficiency in this size separation step. This paper describes the issues which are evolving in this area, and the capability of current and developing techniques to address the problems which need to be overcome.

Jan 1, 1996

By S. Ripke

Between 2002 and 2004, the performance of a six million ton per year iron ore beneficiation plant dropped significantly. In a classic case of “who done it,” was it the mine, the concentrator, an ore change, or something else? While average annual final product grade decreased 8% (indicated by an increase in silicate gangue from 2.76% to 2.99%), the weight recovery also decreased by 8% (from 37.92% to 34.79%). This represents a loss of 832,000 tons of iron ore worth about $16 million for the two year period! The concentrator had been optimized to produce a high grade wet concentrate as feed to the dry side of the plant. But, did optimizing an individual unit operation’s grade give the best overall plant performance? In this paper, the investigation and solution to this mystery will be revealed.

Jan 1, 2007