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By Farzad Moradpouri, Kianoush Barani, M. R. Azadi

The aim of this paper is to assess the effect of microwave treatment on copper sulfide ore for ball milling and bed breakage. Liberation analysis of ground products in eight size fractions showed that microwave pretreatment liberated more chalcopyrite particles from the bed breakage product than the ball mill product. In bed breakage, microwave pretreatment caused a 2% increase in chalcopyrite liberation on average. Microwave pretreatment produces more elongated particles in ball milling and more rounded particles in bed breakage, respectively. Microwave pretreatment produces coarser chalcopyrite particles with a wide range of sizes. This effect is more significant in bed breakage compared with ball milling. Micro-flotation test results showed that in ball milling, treated and untreated materials have similar metallurgical performance and there is a little difference (1%) between the average Cu recovery values. However, in bed breakage, the average recovery for the treated materials is about 5% higher than the untreated materials.

Jul 8, 2021

By Roberto Fustos, Gonzalo Nelis, Víctor Sanhueza, René Gómez

Hang-ups are a challenging operational problem in block caving mines. They interrupt ore flow and imply hang-up removal activities, which take time, increase operational costs, and involve safety risks for workers. In block caving, the number of hangup events of mechanical arches that appear in the drawbell could be decreased if the drawbell geometry is adequately designed based on the expected rock fragmentation. Here, we compile and analyze hang-ups reported in several block caving mines to evaluate the impact of drawbell geometry, rock size, and vertical load on hang-up frequency at the mine scale. Results show that the ratios between drawbell length and d80 (dL/d80), between drawbell width and d80 (dW/d80), between drawbell volume and rock volume (VDB/VP), and vertical stress are critical parameters that define hang-up frequency. These findings confirm previous experimental studies, where a decrease in hang-up events is associated with an increase in these ratios. Additionally, these outcomes are used in a support vector machine algorithm to define categories of hang-up frequency. The results of this classification algorithm are presented in diagrams, which can be used to estimate the hang-up frequency in block caving projects.

Oct 15, 2022

By R. K. Sinha, B. S. Choudhary, Desh Deepak, A. K. Mishra, Hemant Agrawal, Shankar Kumar

There are several methods (empirical, statistical, and machine learning tools) to calculate blast-induced ground vibration. Still, due to complications in the blasting procedure, under varying blasting loads and strata conditions, it is not easy to predict and simulate blast vibration precisely. Therefore, a study was conducted to simulate the field blast data in Ansys software using explicit dynamics. For this study, monitoring of ground vibration for 20 single hole blasts was carried out. The density of emulsion explosives was in the range of 0.9 to 1.15 g/cc. In the laboratory, rock properties were determined from the rock sample collected from the mine site before blasting. The in-hole velocity of detonation (VoD) and the density of the emulsion explosive were also determined. These parameters were used for numerical analysis to know the ground vibrations at specified points. The results of ground vibration predicted by the model are validated using field data.

By Marvin P. Barnes

An attempt has been made to compile and code geologic data relating to twenty of the major porphyry copper districts of North America in such a manner as to permit the use of modern electronic digital computers to retrieve, compare, and build statistical mathematical models from the input. In the exploration process as part of his broader efforts to evaluate the potential of some prospective region, district, or ore body, the experienced geologist consciously or subconsciously compares and fits the observed geologic features to similar phenomena associated with known ore bodies with which he is acquainted. Thus an adequate conceptual "model" of the total geologic environment and type of ore body sought is an essential requirement for the successful exploration effort. Numerous such models of porphyry coppers already exist in the minds and notes of many experienced geologists today. These models are, of necessity, couched largely in qualitative terms and though they may be quite definite in the mind of the porphyry copper expert, the total concept of what constitutes a porphyry copper deposit and environment is difficult to convey in very precise terms. There probably is no such thing as a typical porphyry copper deposit. However, it is well understood that most of the deposits that have been studied have many geological characteristics in common. A logical question then might be: What characteristics are most common or how often do they occur in common, and what is their relationship to other common characteristics ?

Jan 1, 1970

In early 1970, General Mills Chemicals, Inc. announced the availability of en improved liquid ion exchange reagent, LIX® 64N, for the recovery of copper from various solutions, such as dump leach liquors. LIX 64N has been shown to be a considerable advance over LIX 64, and is presently in use in three commercial plants. Results have been very gratifying. For example, one of the plants was designed for operational production of 40,000 pounds copper per day, and in fact reached this output within the third week following startup of the plant. In addition to the operating plants, another is scheduled to come on stream this month with L D( 64N being used to extract and recover both copper and nickel. The chemical properties and operating characteristics of this reagent have been fully described in a previous paper. 1 LIX 64N is quite an effective and selective extractint for copper, even with copper contents as high as 15 g/l, but the reagent is somewhat limited in pH range, and loses some of its extraction efficiency as the pH drops below 0.8. Liquors derived from vat leaching, electrolytic tankhouae bleed streams, or some of the new leach schemes derived to solubilize copper from sulfide concentrates are examples of the liquors that present major problems when treated via liquid ion exchange. LIX 64N could extract some of the copper from such streams, but recovery was limited to about 75 percent. Also, in some parts of the world there are streams which are relatively low in copper (-5 g/l) but which are very high in acid (25-50 g/1 H2SO4). Again, LIX 64N can attain only about 75 percent recovery from such streams. For effective treatment, these streams require a reagent which will maintain the excellent selectivity of LIX 64N, and will

Jan 1, 1971

By Jordi Vives-Costa, J. J. de Felipe, Lluís Sanmiquel, Maria Niubó

The article evaluates the convective heat transfer coefficient of ventilation air in a potash mine. The energy balance is obtained through thermal characterization of the ventilation air and rock, allowing for the calculation of heat transfer parameters. Different models for calculating the convective heat transfer coefficient are analyzed. The results indicate that the Pethukov–Kirilov, Gnielinski, and modified Dittus–Boelter models are optimal for this mine. The study also indirectly examines the conductivity of the adjacent rock, suggesting saturation throughout the studied section and the presence of liquid water upwelling in a specific section.

Apr 7, 2022

By James J. Fallon

The industrial minerals industry is defined loosely and a specific list is presented. Criteria by which to judge prospects and examples are provided. General trends of the industry are observed.

Jan 1, 1984

By R. W. Wittkopp

The Relief Canyon gold deposit is located approximately twenty- four kilometers east of the town of Lovelock in Northwestern Nevada. At Relief Canyon, the Late Triassic Grass Valley Formation has been thrust over the Late Triassic Natchez Pass Formation. The lower plate Natchez Pass Formation is composed of massive gray dolomitic limestone which is locally silty and sandy. The upper plate Grass Valley Formation is composed of shale, siltstone, argillite and quartzite. Gold mineralization at Relief Canyon occurs along the highly brecciated thrust contact between these two formations. Weak gold mineralization often occurs above the thrust in the Grass Valley Formation, however, most of the ore grade mineralization is present below the thrust in the brecciated Natchez Pass Formation or where the two formations are mixed as a result of movement along the thrust. Several types of gold mineralization have been recognized at Relief Canyon. A large amount of the ore is present as a jasperoid breccia, however, significant amounts of ore occur as a mixed breccia composed of upper plate rock, fresh limestone, clay and jasperoid breccia. Gold ore also occurs in a fresh limestone breccia which contains a large amount of clay. Below masses of jasperoid, jasperoid stringers containing gold extend into the fresh limestone. Gold mineralization at Relief Canyon appears to be truly disseminated and has the typically associated trace elements of arsenic, antimony, mercury and fluorine. The Relief Canyon deposit can be classified as a structurally controlled disseminated gold deposit. Other deposits that fit this classification are the Pinson and Dee gold mines.

Jan 1, 1984

By Ari Jokilaakso, Junjie Shi, Zhuo Chen, Pekka Taskinen, Xiang Gao

The amount of copper flash smelting slag has increased during the recent years along with an increasing slag-to-metal ratio. During slag tapping, some copper sulfide is mechanically entrained. As a result, it is necessary to recover copper matte from the slag by suitable methods. At present, the most common way is slow, controlled cooling in a transfer ladle. However, research on the detailed effects of slow cooling and the function of slag modification is rare. This paper described experiments that were performed at different cooling rates (0.5, 1.5, 3, and 7 °C/min), with and without additive. A detailed characterization of the copper-rich phase and its particle size was subsequentlymade using SEM-EDSmicrographs and image analysis software.With a decrease in cooling rate, the particle size of the copper-rich matte phase became larger. The addition of gypsum and carbon as a slag modifier affected the size of the copper-rich phase slightly, and its chemical composition was modified compared with the experiments without additive.

Jul 31, 2020

By J. D. Miller, C. L. Lin

From mine to mill, the 3D characterization of particles ranging in size from meters to micrometers is now possible. A brief review of X-ray tomography for mineral processing is given with recent advances considered, such as high-speed scanning and image analysis procedures to describe important particle properties, including size, shape and composition. Considering these new 3D characterization tools, applications in mineral processing are discussed for high-resolution X-ray microtomography (HRXMT) laboratory analysis of particles ranging from 20 mm to 5 μm, with a voxel resolution of about 1 μm, including (1) multiphase particle characterization by HRXMT and comparison with scanning electron microscopy (SEM), (2) particle damage state as a result of blasting/comminution, (3) liberation characterization to describe expected separation efficiency, (4) exposed grain surface area analysis to explain the flotation of locked particles, and (5) floc size, shape and water content for polymer-induced flocculation. Finally, applications in mineral processing for plant-site analysis using high-speed X-ray computed tomography (HSXCT) are examined, including, for example, coal washability analysis, the analysis of crusher plant products, and the analysis of pebble phosphate products from central Florida. Scanning rates on the order of 1 kg/min for particle sizes ranging from 150 mm to 1 mm are possible, with a voxel resolution of about 100 μm. For coarse particles smaller than 5 to 10 mm, high scanning rates of more than 300 t/h may be possible at a voxel resolution of about 1 mm.

By Yucheng Li, De Huang, Yonghong Liu

Mine frictional resistance is one of the essential parameters of mine ventilation systems, and it is of considerable significance for the prevention and control of mine risks and accident hazards. Frictional resistance requires a lot of resources and time and has errors. To reduce the errors of frictional resistance, a regression model of frictional resistance is proposed based on the correlation analysis of the affecting factors. Through the comparative test analysis of seven regression methods, it is found that the classification and regression tree method for solving the proposed regression model has better performance than other methods. The least square error criterion is used to calculate and rank the importance of the factors affecting frictional resistance. The results show that the cross-sectional area of the tunnel, the support method, and the presence or absence of devices or pedestrian ladders have the most considerable influence on the prediction accuracy of frictional resistance. The support methods and cross-sectional areas are essential input variables. Through the combination test analysis of the influencing factors, the results show that the regression model does not have predictive ability when the number of input variables is less than 3 and the best predictive performance cannot be obtained using all the influencing factors. The best prediction model of resistance is to combine the shape of the tunnel, the support method, the presence or absence of devices or pedestrian ladders, and the cross-sectional area. The method proposed in this paper does not require a lot of resources and time investment, and the frictional resistance error is small. At the same time, it solves the problem of resistance prediction with incomplete data of influencing factors and provides a compelling new method for obtaining frictional resistance parameters.

Jan 28, 2022

By Franklin B. Woodbury

As part of its goal of helping maintain an adequate supply of minerals to meet national economic and strategic needs, the U.S. Department of the Interior's Bureau of Mines is evaluating alternative technologies to treat oxidized taconites. Since process control is an essential element in the application of these process technologies, research was performed with a prototype monitoring system. A Californium-252 neutron source and a thermal neutron capture- gamma ray spectra analysis method was utilized to measure the amount of iron and the percent solids in the process slurries. The concentrate and tailing streams in a 410-kilogram-per-hour (900- pound-per-hour) pilot plant employing a selective flocculation and cationic flotation process were monitored. The results obtained showed that the thermal neutron capture-gamma ray reaction can be used to provide process control parameters.

Jan 1, 1979

By R. M. Tyson

Sulfides present in the troctolitic and footwall rocks are placed into one of three major zones (hornfels, cloud, and basal) on the basis of their stratigraphic position and mineralogy. Hornfels sulfides, enriched in Fe, represent remobilized sedimentary sulfide. Sulfides from the Cloud Zone are probably magmatic and are enriched in PGE, Cu, Ni, and Ag. The basal sulfides, composing most of the ore, resulted from contamination of the magma by remobilized sedimentary sulfide. The basal sulfides exhibit a differentiation trend in their mineralogy and chemistry. PGE, Cu, and Ag are enriched with increasing differentiation which is attributed to fractionation within an immiscible sulfide liquid.

Jan 1, 1986

By Yuanyuan Wang, XUEWEN WANG, Jinzhi Wei, Ligang Wen, Muxin Jia, Zhengyao Li

The abstract discusses the use of disodium carboxymethyl trithiocarbonate (D8) as an effective depressant in the flotation separation of stibnite and pyrite. The study investigates the mechanism behind D8's selective inhibition of pyrite, utilizing techniques like micro-flotation experiments, contact angle measurements, infrared spectroscopy, adsorption capacity analysis, and zeta potential measurements. The findings reveal that D8 physically adsorbs onto both pyrite and stibnite, but its adsorption capacity on pyrite is significantly higher. This adsorption enhances the hydrophilicity of the pyrite surface, hindering the adsorption of the collector and effectively depressing pyrite flotation, while having minimal impact on stibnite floatability.

Mar 14, 2022

By Cyrus W. Field

The Pacific Northwest as defined in this review comprises an exceedingly large and geologically complex terrain that occupies the 'Western Cordillera mobile tectonic belt. This metallogenic province is approximately 2100 miles long and 350 to 500 miles wide. It extends north-northwest from northern California and Nevada, through western Idaho and Montana, Oregon, Washington, British Columbia, and southwestern Yukon Territory, to southern Alaska, and west from the western flank of the Northern Rocky Mountains to the continental margin (Fig. 1). Many detailed and thorough exploration programs that have been conducted by mining and petroleum companies for over a decade have demonstrated that porphyry-type deposits are both numerous and wide-spread throughout this province. Although the Granby Mining Company extracted about 34 million tons of copper sulfide ore from Copper Mountain during the period 1900-1957, intentional large-scale production of porphyry-type ores was first initiated in 1962. It began at Bethlehem Copper Corporation's East Jersey orebody in the Highland Valley District of south-central British Columbia, approximately eight years after Mr. H. H. Huestis rediscovered that broad zone of copper-molybdenum metallization and recognized its potential significance.

Jan 1, 1973

By S. Eugene Mills

Twenty-five years ago, when I began my sales life marketing minerals, there was little or no contact between sales people and production people. In those days, it was not uncommon for me, as a salesman, to learn of production problems existing in my company from my customers. Today, in my opinion, any successful mining company must keep production people fully aware of circumstances that effect service to the users of the product. Basically, feldspar is presently consumed by the glass and pottery industries the same as 100 years ago. The consuming public little realizes the origin of so many things they use daily and take for granted. Feldspar is utilized in the glass that contains our Coca-Cola, Pepsi, wines, liqueurs, beer and the assorted gob¬lets from which we drink these lovely brews, the industrial glass upon which all industry depends, the bathroom plumbing fixtures that make life so different from the days of the out-house, the beautiful and durable china we enjoy at mealtime. The electricity we use requires insulators that demand feldspar. In our home ap¬pliances, automobiles, toys and airplanes, we find feldspar. I could go on and on, hopefully soliciting your help in making our taxpaying and non-taxpaying fellow man aware of the burdens he may acquire when unthinking, over-enthusiastic environmentalists foist unnecessary hardships upon the mining industry. Feldspar is marketed primarily sized from 20 mesh to 325 mesh. The glass industry requires feldspar ground 20 mesh to 40 mesh size; the pottery industry requires material from 150 mesh to 325 mesh size. One large glass plant may require up to 100 tons per day and more, whereas a small plant may use less than 5 tons per year. A large pottery plant may require as much as 50 tons per day, a small potter only 500 lbs. per year. The feldspar

Jan 1, 1977

By E. Watkins, S. J. SCHATZEL, K M. AJAYI, V. Gangrade, Z. Khademian

A stochastic discrete fracture network (DFN) model is developed based on mine site core log data to predict the horizontal and vertical permeabilities from the surface to the top of the caved zone at a longwall mining site in southwestern Pennsylvania. One hundred DFN realizations were generated to determine permeabilities for the isolated zone over an abutment pillar after mining the second panel. The results from this study show that the vertical and horizontal permeabilities from the DFN model agree closely with field measurements, which indicates that the resultant permeability obtained from the field measurements is representative of the predicted permeabilities. With this agreement, the aperture data for other zones of the mine could be obtained from the geomechanical model — specifically, for the fractured zone over the gob. Based on the successful validation of this model, this model could be further developed to predict the permeability of the fractured zone over the gob with fracture aperture obtained from the geomechanical analysis. This will complete the fracture characterization of the overburden, which could be used to predict potential shale gas flow to the mine in the event of a breach. This prediction could provide information on the associated risk of a casing breach and determination of methods to proactively prevent such an occurrence.

Feb 1, 2023

By Volkan Arslan

This study aimed to remove the contaminants in quartz sand by using an eco-friendly method and to obtain high-purity quartz. For this purpose, ultrasound-assisted acid leaching was applied. Equal amounts of a mixture of diluted hydrochloric and oxalic acids were used as the solvent. Response surface methodology (RSM) was used for optimizing, modeling, and predicting the experimental parameters. The correlation coefficient ( R2) of the proposed quadratic model for the relationship between iron removal yield and test parameters was calculated as 0.9731 and it was determined that the predicted and actual values were compatible. Finally, optimization experiments were made and optimum experiment conditions were revised and determined as 83.38 °C of leaching temperature, 196.35 min of leaching time, 2.86 M of acid concentration, and 202.24 W of ultrasound power. Under the optimum conditions determined after optimization, the highest yield of iron removal was determined as 95.08%. Under the optimal parameters, the SiO2 content of the concentrates increased from 97.841 to 99.907% and the Fe2O3 content reduced from 0.225 to 0.011%.

Jul 12, 2021

By W. Burr Bennett

The prestressed concrete industry in particular, and the precast concrete industry to some extent, are rank newcomers to the concrete construction field compared to the cement, ready-mixed or concrete masonry industries. This young industry reflects its youth and vigor in its enthusiasm, optimism and the belief that it can reach any goal it chooses to set -- and it is setting its sights high. The prestressed and precast concrete industry fully expects to become the major structural and architectural material by the 1980's. Before exploring how the industry expects to reach this goal, a brief look at the origins and the growth of the industry may be useful in an evaluation of the feasibility of this goal. It was always recognized that concrete, strong and efficient for supporting loads which cause compression, was weak and inefficient when used to carry loads which induce tension. Thus the reason for reinforced concrete in which the concrete efficiently carries the compression in a flexural member while low grade steel bars reinforce the concrete in the areas 'of tensile stress. (Fig. 1). The steel being relatively inexpensive, can passively, but quite effectively carry tensile force while the concrete carries compression. The concrete in contact with the reinforcing also protects the steel from corrosion and acts as insulation to provide a superior "built-in" fire resistance. The major disadvantage of reinforced concrete relative to its main competitor, steel, is its weight in relation to its load-carrying capacity. Reinforced concrete systems, such as waffle slabs, I-beams, thin shells, etc. ,

Jan 1, 1971

By D. Zim

Mining activity in South America is a growing enterprise. One of difficulties found in many areas of the South American continent, especially in north Chile and south Peru, is the shortage of water supply. In order to overcome this difficulty some mining companies proposed to transport the water from Pacific Ocean up to the mountains. This can be accomplished by the use of stainless steel pipelines, but this is a cost prohibitive solution and is also subject to severe pitting corrosion in a saline environment. The use of mild steel may be a lower cost solution than stainless steel as the material of construction for pipelines but it is subject to corrosion anyway. The corrosion in this case can be internal or external corrosion although cathodic protection as well preventive maintenance usually is enough to mitigate external corrosion without the need to shut down the pipeline. The same is not true about the prevention of internal corrosion. It is not practical, sometimes not even possible, shutdown a pipeline to carry out an inspection and fix sections where potential failures are detected. It is possible avoid corrosion caused by sea water within the mild steel pipelines by applying a proper chemical program designed to virtually eliminate dissolved oxygen in the water commonly called deaeration.1 This type of treatment obviously involves additional capital investment since it requires the construction of one deaerator with the first pumping station and additional equipment at each point where the water can come into contact with oxygen. Deaerators will increase operational costs and subsequent injection of chemicals will be required in the case of multiple degasification facilities thus increasing the consumption of chemicals. grams based on oxygen scavengers, the objective of the present study is to develop a new water treatment capable of preventing mild steel corrosion in aerated sea water. The new treatment must be able to prevent both generalized and localized (pitting) corrosion and overcome the necessity to construct and operate deaerators.

Feb 23, 2014