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By H. E. Hawkes

Reconnaissance mineral exploration based on the distribution of ore metals in stream sediments has become a generally accepted method of mineral reconnaissance. This approach seems to work almost equally well in all climates and in all kinds of terrain, provided of course that the ore deposits being sought are exposed at or near the surface and are actively undergoing erosion. Nobody with any experience in the field would question the validity of the concept on which stream sediment reconnaissance is based. Considerable dispute does arise, however, when the subject of density of sample sites per unit area, or sample spacing, comes up for discussion. What is the optimum balance between completeness of coverage and cost? The tacit assumption is frequently made that a greater sample density necessarily leads to more complete coverage and hence a lower probability of missing an important discovery, without regard for the size of the stream sample or the topology of the drainage pattern. The purpose of this paper is to attempt to bring the problem of site selection in stream sediment sampling into better focus, and to present a formula that may help in planning reconnaissance programs.

Jan 1, 1976

By K. Hanumantha Rao, A. Javadi Nooshabadi

"Formation of hydrogen peroxide (H2O2), an oxidizing agent stronger than oxygen, by chalcopyrite (CuFeS2), which is a copper iron sulfide mineral, during grinding, was investigated. It was observed that chalcopyrite generated H2O2 in pulp liquid during wet grinding and also in the solids when placed in water immediately after dry grinding. The generation of H2O2 during either wet or dry grinding was thought to be due to a reaction between chalcopyrite and water where the mineral surface is catalytically active in producing •OH free radicals by breaking down the water molecule. The effect of pH in the grinding medium or in the water in which solids are added immediately after dry grinding showed that the lower the pH value, the higher the H2O2 generation. When chalcopyrite and pyrite are mixed in different proportions, the formation of H2O2 was seen to increase with increasing pyrite fraction in the mixed composition. The results of H2O2 formation in pulp liquid of chalcopyrite and together with pyrite at different experimental conditions have been explained by Eh-pH diagrams of these minerals. This study highlights the necessity of revisiting the electrochemical and/or galvanic interaction mechanisms between the chalcopyrite and pyrite in terms of their flotation behavior.IntroductionHydrogen peroxide causes nonselective oxidation of sulfide minerals if present in pulp liquid. Oxidation of sulfide minerals takes place when they are exposed to atmosphere and during the grinding process when the particle size is reduced for flotation. The oxidation of chalcopyrite leads to iron dissolution from the particle surface and from a metal-deficient, sulfur-rich surface (Fairthorne et al., 1997). Other studies report the formation of iron hydroxide on the surface with the metal ion dislodged on the surface (Buckley and Woods, 1984; Chander, 1991). The chemical reactions for the oxidation of chalcopyrite in alkaline and in acidic solutions with the addition of oxidants, such as oxygen or hydrogen peroxide, are shown in Eqs. (1) and (2), respectively (Shi and Fornasiero, 2010)."

Jan 1, 2015

By Yi-Hsuan Chen, Jürgen Brune, Candace S. J. Tsai, Alejandro Munoz, Connor Krause

This study highlights the significant presence of submicrometer- sized airborne particles in underground coal mines, especially around the belt conveyor drift areas. Using realtime instruments and gravimetric samplers, the assessment revealed that particle concentrations were notably higher in the belt entry compared to other locations, with a strong presence of submicrometer- and nanoparticle-sized dust. The study’s findings emphasize the importance of addressing small particle exposure, as these particles, composed of harmful substances like calcium, copper and iron, can pose serious health risks to miners. This research emphasizes the importance of improving air exposure estimation through more effective monitoring and characterization techniques to better understand and reduce workers’ exposure to hazardous airborne particles in the mining environments.

Apr 1, 2025

By Makoto Terada

The most important consideration in planning the plugging and sealing of a mine for mine water control is to predict the water flow from the mine. For this purpose, a method of numerical analysis on the water behavior in the ground at the concerned mine area was developed and the mine water flows were simulated. A hydrological survey at the surface of the mine determined the recharge rate of ground- water and the apparent permeability of ground.

Jan 1, 1982

By D. Castillo

The effectiveness of a flotation column is due principally to the addition of wash water to the froth phase. The wash water flow rate can be significant, especially so for systems yielding a high weight recovery of fine solids, e.g. zinc sulfide flotation. Therefore, it is critical to recognize and assess the impact of the water addition upon upstream separation stages. This paper examines column flotation circuit configurations using data from a portable 2 t/day pilot plant. The objective is to provide an improved basis for column design, either as a retrofit or as part of a new circuit.

Jan 1, 1990

By Javad Sattarvand, Frimpong Kwaku Asare

The safe evacuation of miners during an emergency in the shortest amount of time is one of the most essential features of a mining operation. Despite advancements in mine evacuation research, the usage of mine vehicles during evacuation has not been considered. The majority of recent studies have been done on miners’ evacuation on foot. Mathematical formulations including Minimum Cost Network Flow (MCNF) models, Dijkstra's algorithm, Floyd-Warshall algorithm, and Ant Colony Optimization models have been used to solve mine evacuation problems. These models, which concentrate on determining the shortest escape routes during the evacuation, have been found to be computationally expensive and may not offer the best solutions in some cases. The goal of this paper is to incorporate light vehicles in the evacuation process using a mixed-integer programming approach. The methodology aims to minimize the total time required to evacuate the mine, ensuring minimal exposure of the miners to the adverse conditions that triggered the evacuation.

Jun 25, 2023

Contributions made by mining have played a much more significant role in the development of civilization than is generally conceded by historians or recognized by ordinary citizens. In modern society, mined products pervade all industry and the lives of all civilized people. Early man relied largely on stone and ceramics, and eventually metals, to fashion tools and weapons. Civilization was advanced by discoveries such as abundant supplies of high-quality flint in northern France and southern England and firesetting to break rock. Middle Eastern cultures flourished not only because of agriculture and trade, but also because of mineral-rich deposits nearby. The earliest miners date back perhaps to 300,000 BC; their quest was for nonmetallic minerals (chert, flint, obsidian) suitable for utensils and eventually for weapons. Other rocks and minerals (ceramics, clay, salt, meteoric iron) attracted the miners for jewelry, cosmetics, construction materials, food seasoning, and coinage. At first, their excavations were confined to the surface, either pits or placers. But by about 40,000 BC, mine workings had been extended underground as short adits or shafts, and by 8000 BC as elaborate interconnected openings 300 ft (90 m) in depth. Metallurgical separation of metals from their ores and their subsequent fabrication evolved gradually over the centuries, copper being the first liberated (c. 7000 BC) followed by lead, silver, gold, and iron. Man enhanced both the sophistication of his

Jan 1, 2008

By John J. Stetler

The Companhia Vale do Rio Doce in Brazil operates one of the most extensive systems in the world for the mining, transportation, processing, pelletizing and shipping of high grade hematite iron ore and pellets. Current shipping of unbeneficiated, sized, high grade ore from its ports at Tubarão and Vitória is now at the rate of 17,500,000 metric tons annually. An increase in this annual rate is now under study. Using the technology and facilities of Lurgi (1) and Arthur G. McKee company CVRD undertook a program to process and pelletize two types of fines - "Blue Dust" and ?Itabira Fines?. Blue Dust is a high grade fine ore which was bypassed while mining the direct shipping ores and which, also, exists as a very large ore body called the Conceição Mine. Itabira Fines is a lower grade of fine ore which is comprised of in-situ fines and, also fines which are generated in sizing the direct shipping ores for a rigid specification market.

Jan 1, 1970

By F. J. Susko

The Bureau of Mines applied a flotation model to the hydrodynamics of the Bureau-developed rapid flotation system. Rapid flotation is a process which separates the bubble-particle attachment and froth-pulp separation stages of the flotation sequence into two discrete unit operations allowing the operations to be individually optimized. Both an air-injected hydrocyclone and an in-line mixer were used as the bubble-particle attachment unit and a shallow-depth froth separator was used to separate the ore-laden froth from the pulp. A 10-L/min batch system was tested on a coarse coal feed sample. The system was tested using two different bubble-particle attachment units at various aeration levels in order to test the flotation model. The results of the flotation model reflect general trends observed in the experimental data.

Jan 1, 1993

By Hemendra N. Kalia

To plan a safe and efficient coal mining operation, the design engineer should use all the available information regarding the property to be exploited. The reliability of the mining operation must be as high as possible so that the plants relying on the coal can operate at the maximum design capacity. A good design should incorporate all of the known geological characteristics of the deposit, the structural and physical properties of the coal, as well as the rock which will form the roof and floor of the mine openings. A systematic method is proposed as a guide to insure a mine design that will be safe, efficient and will minimize surface disturbances resulting from mining operations. It is anticipated that the method proposed will result in maximum extraction at perhaps minimum cost to the operator. In general, to develop a mining area, several factors are systematically reviewed: (1) determination of the economic minability of the deposit, (2) the computation of the coal reserves, (3) the marketability of the coal, and (4) the life of the property. In general, boreholes are drilled in a predetermined pattern and geophysical or geological methods are used to log the boreholes. The information so obtained is primarily used to determine the quality and the extent of the deposit and to determine to some extent such geological features as faults, barren areas, washouts, and channels.

Jan 1, 1973

By Nikhil Dhawan, Sanjay Pindar

The limited lifespan, ever-growing demand, and significant lithium and cobalt content are responsible factors for the immediate recycling of discarded lithium-ion batteries. Discharged batteries were dismantled, segregated, and size reduced to recover cathode and anode material. The active cathode material comprises LiCoO2 (65.8%) and LiMn2O4 (34.2%) and was carbothermal reduced with recovered graphite in a microwave furnace followed by water leaching and magnetic separation. A Box Behnken statistical experimental design is used for process optimization. Both cobalt and manganese report to magnetic fraction, whereas graphite and lithium carbonate report to non-magnetic fraction and solution crystal respectively. The final product comprises of cobalt 73% and manganese of 14% with process yield of 36% and saturation magnetization of 76 emu/g.

May 16, 2020

By Mirko Martini, Marcelo Benaglia, Andrea Codalli

Riachuelo Lot 3 forms part of a sanitation programme being implemented in Argentina to relieve the Riachuelo river basin from its current contamination. The programme, by far the most important in its kind in the country during the last decades, will expand the sewage capacity of Buenos Aires and will benefit an area of 4.3 millions inhabitants by intercepting a number of waste water discharges and conveying them to a new treatment plant prior to final discharge into the Rio de la Plata. The project foresees amongst other works the construction of an onshore 48 m deep shaft at the outlet of the treatment plant plus a 4,3 m inner diameter outfall tunnel of 12 km length. The last 1.5 km of the alignment is fitted with 34 vertical risers jacked from inside the tunnel to allow the discharge and dilution of the treated effluent into the Rio de la Plata. This paper describes the peculiarities and challenges, both in terms of design and in terms of construction, of the outfall tunnel, which was entirely bored under the Rio de la Plata using a 5.2 m cut diameter Tunnel Boring Machine (TBM). On one hand, the tunnel segmental lining was designed to work in tension during the system flow rate peaks while on the other the tunnel excavation faced a variety of complex conditions, such as crossing water bearing permeable soft ground formations and advancing at face pressures in excess of 3,5 bars for the entire route.

Jun 13, 2021

By Jr. Moulton

Extractions of minerals from Searles Lake brines have taken place since 1873. Early operations were for borax and raw trona found on the surface, expanded after 1914 to include potash, salt cake, and soda ash. A new soda ash plant now in operation will double area production. The evaporite beds were formed by desiccation of Eastern Sierra runoff. The resulting series of brine-bearing salt beds supply the fluids necessary to feed the area chemical plants. Production methods include evaporation and crystallization for potash, borax, and salt cake; carbonation of brine to recover soda ash; and organic extraction of borax.

Jan 1, 1980

By A. Adu-Acheampong

Stope instability at Ashanti Goldfields Company Ltd. (AGC) is a major concern. Using information from field mapping, major discontinuity sets were defined, Rock Quality Designation (RQD) was determined. The stability of wedges in the stope walls was assessed using the commercially available computer program UNWEDGE(Rock Science, 1992). Analytical results indicate that the presence of graphite infilling in joints contributes to instability, while steeply dipping joints control wedge slabbing and wedge toppling in the hanging wall. Stable stope widths and dimensions were determined to range from8.1 to 30 meters (m).

Jan 1, 2003

By A. Vien

MOCCA is a Multivariable Optimal Constrained Control Algorithm developed specifically for non-square industrial control applications with practical difficulties such as interactions, time delays, constraints, modelling development, etc. MOCCA consists of an off-line simulation/translation module, for tuning the control parameters, and an on-line module that implements the designed control law. This paper describes an evaluation of MOCCA on the Hemlo grinding circuit which comprises one open circuit ball mill and two closed circuit ball mills in series. In this case a 4x4 unconstrained control problem was considered. The manipulated variables included the fresh ore feed rate and three pump box water additions. The controlled variables were the grinding circuit product particle size and three pump box levels. In this application soft constraints were implemented through control action and control error weighting. The feedforward capability of MOCCA was used to compensate for a measured water flow disturbance to one of the pump boxes. MOCCA performed very well during plant evaluations when compared to the original classical multi-loop control strategy and proved to be quite robust. Perhaps most importantly, the process engineers and plant operators have a high level of comfort both in understanding MOCCA's general operating principles, and with its demonstrated performance.

Jan 1, 1991

By Robert F. Conley

Attrition milling, once employed exclusively for the dispersion of pigments, has in recent years found a host of new applications in the area of mineral processing and mineral-pigment production. Broadly categorized, attrition milling is divided into two classes, as defined by the machinery's function, vibratory milling and rotational milling. Each mill type has been defined as a variation on ball milling and the terms, "vibratory ball mill" and stirred ball mill" appear in the literature. The primary design differences between attrition and ball mills are: (1) a stationary canister (or shell) (2) smaller grinding media (3) grinder energy is motor limited rather than gravity limited (4) strong media/feed size dependance.

Jan 1, 1983

By D. Men, R. Q. Honaker, J. C. Hower

"Maceral separation is one possible technique to expand coking coal resources, either by increasing the blending ratio of non- or slightly caking coal or rationally utilizing the coking coal according to the different behaviors of macerals in coking. The success of maceral enrichment for a given coal using flotation is dependent on the differences in flotation kinetic rate among macerals. This paper presents the flotation rates and zeta potentials of the vitrinite-rich and inertiniterich maceral concentrates obtained from six coal samples of different ranks – from high-volatile B bituminous coal with mean random vitrinite reflectance (Rrandom) of 0.64 percent to low-volatile bituminous coal with Rrandom of 1.73 percent – using a float-sink procedure. The flotation results show that vitrinite-rich concentrates can be produced in tap water using froth flotation only with frother for the high-volatile B and A bituminous coal samples, but there was no good performance for the high-volatile C bituminous and medium- to low-volatile bituminous coal samples. The zeta potential results show that froth flotation could probably separate the high-volatile C bituminous coal samples well by adjusting pH, but there was no good performance for the higher-rank coal samples. IntroductionMetallurgical coke is used in blast furnaces for steel production and is produced by the carbonization of coking coal. Because caking coals are rare and expensive, they are often blended with non- or slightly caking coals. Considering the tight supply-demand situation for coking coal in China, it is important and urgent to develop highly efficient technologies for rationally utilizing and expanding coking coal resources (Mochizuki et al., 2013)."

Jan 1, 2015

By Raul A. Deju

A theoretical and experimental study was made of the surface phenomena occurring in a silicate - sulfonate system and a silicate -amine system, Experiments were conducted varying the collector concentration to examine its effect both on the total surface sorption and the rate of sorption. The results were compared to a theoretical model based on a Langmuir-type isotherm, Finally, the flotation behavior of selected silicate minerals was predicted from the sorption results and an explanation for the flotation of silicates postulated on the basis of both the theoretical predictions and experimental data.

Jan 1, 1967

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 Paul E. Rosten

This paper describes some of the latest improvements that have been incorporated or planned by the Cleveland-Cliffs Iron Company to reduce operating costs and improve pellet quality. The Cleveland-Cliffs Iron Company operates and manages mining, beneficiation, and pelletizing operations in Michigan, Canada, and Western Australia. This paper deals with the grate-kiln pelletizing operations at Republic, Humboldt, Tilden, Empire, and Pioneer in Michigan, and the Adams and Sherman in Ontario, Canada. Table I characterizes .each operation in regard to location, ore type, pellet capacity and date that pellets were first produced. All of the operations with the exception of Pioneer and Tilden, utilize downdraft-two-pass grate cycles of drying followed by preheating. Pioneer utilizes an all-downdraft, three-pass grate cycle which consists of three drying zones followed by the preheat zone. The Pioneer and Tilden cycles have been described previously. (1) (2)(3) Tilden utilizes a three-pass grate cycle with a stage of updraft drying, followed by two downdraft drying stages. Recuperation systems which supply hot gases to a drying zone from second stage cooling were designed and furnished for Tilden I. Tilden II will be identical. Empire IV will also be furnished with a recuperation system. The Adams grate-kiln system was retrofitted with a recuperation system. This paper will summarize some of the efforts that are in effect or planned for grate-kiln pelletizing systems to (1) reduce operating and maintenance costs, (2) reduce energy requirements, (3) improve product quality, and (4) meet environmental standards.

Jan 1, 1977