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By Tiago Seixas Bittencourt

Technological developments, associated with the constant worry about the environmental impacts arising from industrial activity, it has driven the development of technologies and practices for efficient fumes and particulates capture arising from the manufacturing processes of steel in steel plants in general. Currently, the electric steelshops in operation with Electric Arc Furnaces (EAF), seek parameterize/design dedusting systems able to retain most of the particulates generated during melting and refining of steel in FEA through configurations of equipment, technologies and parameters operation in order to equalize the antagonistic relationship between effective fumes capture and energy balance of the EAF. The present work gets as a fundamental premise to evaluate critically the possible different settings of the usual dust removal systems, as well as their respective classical parameterizations. The work main purpose is to establish a general rule evaluation technique for dedusting system considering the different modes of operation of an Electric Arc Furnace.

Jul 30, 2018

COLORADO SECTION CHARLES M. MACNEILL, Chairman, GEORGE M. TAYLOR, Vice-Chairman, FRED CARROLL, Sec.-Treas., State Museum Bldg., Denver, Colo. WALTER W. CASE, H. E. COLLBRAN. The annual meeting of the Colorado Section was held on the evening of Jan. 24, at the University Club, Denver, Colo.; SO members and guests were in attendance and the meeting was considered one of the most interesting ever held by the local section. After the usual dinner, the officers whose names are given above were elected for the ensuing year. Dr. David T. Day and Dr. G. H. Clevenger, of the Bureau of . Mines, were present and enlightened us with short talks on oil shales and other work of the Bureau. Mr. J. V. N. Dorr was home from a visit to New York and Washington, and told us something of the war work now going on at our National Capitol. Retiring Chairman Loughridge had been insisting for months that this meeting should be given up chiefly to listening to someone who could give his personal experience in going "over the top" in western France; after a long search he succeeded in finding Sargt. F. C. Strickland, M . M., of the Second Canadian Mounted Rifles, who had very recently been discharged from the hospital with permanent disabilities and has accepted recruiting service rather than a discharge. The success of this plan was evidenced by the close attention accorded the speaker for almost two hours, during which he described conditions, hardships, successes and failures of warfare on the western front. Hardly a listener moved during this talk, and all left with a. feeling that they would have liked to hear more. FRED CARROLL, Secretary.

Jan 4, 1918

By Frank E. Cash

The information in this report covers the accident experience of the pebble-phosphate industry of Florida for 1935 and 1936, as well as the 5 years 1930-34, inclusive, statistics of which were published in Information Circular 69174/. The compilation and publication of such accident experience statistics enable the pebble-phosphate industry, as well as other industries, to consider relative hazards and to compare experience and thereby promote accident prevention.

Jan 1, 1937

By H Y. Niu

The coal left in the goaf is easily submerged by groundwater damage. During the mining process of the underlying coal seam, it is necessary to drain the water in the overlying goaf. The coal sample is prone to spontaneous combustion after being soaked in water and air-dried. To explore the effect of micro-functional group transformation of water-immersed coal samples on the spontaneous combustion characteristics of coal samples during the low-temperature oxidation process. Using the experimental method of infrared spectroscopy, the migration law of special functional groups under different oxygen concentrations of water-soaked coal samples was analysed. By means of thermal analysis, the endothermic and exothermic properties of the functional groups in the water-soaked coal samples were studied. The results show that: the higher the oxygen concentration, the more oxygen-containing functional groups in the water-soaked coal sample, compared with the 18 per cent oxygen concentration, the 14 per cent oxygen concentration has a small increase, and the chain length is shortened. The temperature increase together with the oxygen concentration content determines the functional group content, the pyrolysis process produces some functional groups. The lower the oxygen concentration, endothermic rate decreases and endothermic temperature increases, the higher the ignition temperature of coal oxy-combustion, the lower the total heat release, the higher the burnout temperature, and the faster the oxygen-absorbing weight gain and the conversion of functional groups. Below 14 per cent oxygen concentration, the oxidative combustion process will be greatly reduced. The results provide a theoretical basis for preventing long-term water-soaked coal body oxidative spontaneous combustion in shallow buried coal seams.

Oct 12, 2022

By R. J. Traill

Introduction Following the discovery of high-grade deposits of pitchblende in the Great Bear Lake area of the Northwest Territories by Mr. Gilbert LaBine in May, 1930, samples were submitted to the Mines Branch for examination and investigation as to suitable methods of treatment (1). The purpose of this paper is to present, briefly, the results of the investigative work conducted on the ores and an outline of the methods developed for the extraction of the radium content and recovery of the by-products. The paper is presented in two parts. Part I gives a review of the history of radium production and of the principal processes used in other countries. Part II describes the work and gives the results of the Mines Branch investigation. Part 1-Radium Production In Other Countries Historical Outline Uranium was discovered in 1789, and more than a century later Madame Curie, while studying the physical properties of this element, observed that the ore of uranium exhibited greater activity than the pure uranium com-pounds she had prepared and traced the cause to the presence of a new element which she named radium. Eventually, research proved radium to be a disintegration product of uranium, and always present in uranium ores.

Jan 1, 1933

By C Mpodozis

Central Andean (22¦S to 34¦S latitude) Miocene giant ore deposits share common features that reveal their origin. Tectonic and magmatic features include a relation to a shallow subduction zone, an association with the waning or initiation of a magmatic episode, emplacement at the time of uplift associated with crustal thickening and formation at times of major magmatic changes along the Andean margin. Rare Earth Element (REE) signatures in magmas erupted near the time of mineralisation indicate a progressive change from equilibration at depth with a hydrous, intermediate-pressure amphibole-bearing mineral residue to equilibration with an anhydrous high-pressure garnet-bearing assemblage. These features point to a common history. First, a relatively shallow subduction zone leads to hydration of a cool mantle wedge providing a source of fluids which builds up over at least several million years. Arc magmas formed at this time equilibrate with a hornblende-bearing residual mineralogy. Second, a compressive tectonic regime leads to crustal shortening and thickening that facilitates entrapment of arc magmas in the crust. Eventually, the magma-weakened crust yields to horizontal compression causing rapid crustal thickening. Fluids required for mineralisation are liberated as amphibole-bearing assemblages break down to garnet-bearing ones and over pressured fluids are released from plutons. Mineralisation subsequently ceases in the region unless continued dehydration of the slab and mechanical thinning of the continental lithosphere causes the previous conditions to repeat. The type of mineral deposit generated depends on the pre-existing continental lithosphere and the distance from the trench.

Jan 1, 1999

By Robert Lee Stahl

Comprehensive field tests were made by the Federal Bureau of Hines at the Conda open pit mine near Soda Springs, Idaho, to determine whether surface geophysical techniques could be used to detect and delineate faults in phosphate deposits. The tests included seismic refraction, magnetometry, electrical resistivity, and airborne photography. Of the several geophysical techniques tested in the field, horizontal resistivity profiling was the most effective method for diagnosing faults. The method is quick, inexpensive, accurate, and can be easily used by mining company personnel to detect and delineate faults.

Jan 1, 1975

By William C. Peters

The Alpine-Himalayan system, the only major active tectonic belt mainly exposed in a continental mass, is of increasing interest to exploration geologists as well as to theoreticians. Answers to the broader problems of plate tectonics are being sought in this intricate system where the geosynclinal concept was born and where the geotectonic cycle was first applied to metallogeny. The search is all the more intense because it involves scientists from more than a dozen countries with a stimulating variety in perspective. The international Geodynamics Project has allocated the Alpine-Himalayan system to two separate study groups with one directing its attention to the Alpine-Mediterranean region and the other giving consideration to the Himalayan region. This geographic division is accepted in this paper, with remarks being confined to the former and to the west of boundary zone between the European-Asian and the Southeast Asian plates as envisioned by Dewey and Bird (1970). The region is well-mapped in some parts and it includes some of the most intensely-studied geology, most classic mines, and newest orebody discoveries. Within the region, an Alpine-age copper-molybdenum metallogenic belt extends from Rumania to Pakistan. The belt can be considered in terms of plate tectonics, and there is the possibility of using plate tectonics concepts in exploration.

Jan 1, 1973

By Edward P. Barrett

Iron ore, when subjected to reducing gases at a temperature suitable for reduction of the oxide but not high enough to melt the ore or metal formed, is converted into metallic iron. The product, being the original piece of iron oxide minus its oxygen, is sponge-like in appearance when viewed under a magnifying glass, and hence is called 'sponge iron. Sponge iron was probably the form in which some of the first iron was recovered from the ores. As early as the eighth century the Catlan forge developed into a low shaft furnace known as the high bloomary, in which iron was produced in the form of a pasty mass. These furnaces were increased in height, and with increased temperatures came the production of liquid cast-iron, at first undesirable because of lack of knowledge of methods for working it. In 1340 the first true blast-furnace was built iri Belgium. Some castings were made, but the greater part of the iron was converted into wroughtiron blooms by a crude puddling process. Charcoal was the universal fuel until the latter part of the seventeenth century, when coke was first used in England. Larger scale developments of methods of refining pig-iron followed. In I 885 Bessemer built his first converter in England, and within a few years the Siemen' s regenerative open-hearth furnace was developed, also in England, to produce steel. Then followed the enormous expansion in the metallurgy of iron. The idea of a direct process for the production of iron and steel has persisted during all of this time.

Jan 1, 1925

The future phosphate rock deposits in South Florida contain a significant fraction of dolomite. The high MgO content of the rock is undesirable in the production of phosphoric acid. Several flotation schemes have been attempted to separate dolomite from phosphate rock. Alternately, Selective Flocculation process has been suggested to separate dolomite from apatite. A high MgO content rock was simulated by a 30:10:60 synthetic mixture of apatite, dolomite and silica. Single mineral selectivity was observed in the mixed mineral systems apatite-silica and dolomite-silica with Polyacrylic acid (PM) and Poly(ethylene oxide) (PEO) flocculants respectively but not realized in apatite-dolomite system with PEO flocculant. Heteroflocculation, suspected to be the major reason for loss in selectivity, was minimized by addition of a Site Blocking Agent (lower molecular weight fraction of PEO). Process parameters such as size reduction schemes, flocculant/SBA dosage, and pH were investigated to achieve the desired separation. The selectivity obtained in binary mixed mineral tests was translated into the ternary mixed mineral system, viz. apatite-dolomite-silica. In this presentation surface chemical characterization of the samples and their flocculation behavior will be discussed.

Jan 1, 1994

By S A. Ravishankar

In heavy minerals separation, the titanium and iron oxide phases are separated from silicates in the coarser particle size range (80 - 150 mm) using magnetic and electrostatic separators. With the ongoing challenge of heavy mineral ore deposits getting increasingly finer in particle size, conventional separation equipment suffers from the ability to process this material at the same throughput rate as coarser particles. A variety of magnetic separation technologies were developed to perform at a much finer particle size range, down to 2 mm in the clay industries mainly to remove titaniferrous oxide particles. Complementing the developments made on the physical aspects of magnetic separation, Cytec Industries has recently developed a ‘bolt-on’ chemical enhancement technology for magnetic separation (CEMS). This is to enable separation of finer particles, and weakly paramagnetic titanium phases from diamagnetic silicates that are not amenable to magnetic separation. This paper will provide an outline of the technology, illustrate its ability to process a wide variety of ores, and also discuss plant limitations. The major advantages of chemical enhancement technology to magnetic separation includes: simple dosing equipment extension to existing magnetic separation technology; ability to produce product of comparable quality with improved cost effectiveness, when compared to incumbent flotation; removal of impurity minerals over wider size range; enhanced removal of non-magnetic impurities; and improving the process robustness. Furthermore, chemical enhancement technology for magnetic separation has also emerged as a platform for removing impurities at lower levels in other mineral systems as well.

Oct 5, 2011

By F. Karakas

Water based paint formulations consist of some industrial minerals with quantities varying from 20 to 50 %. Quality of paint is directly related to these minerals used as pigment or filler in the production. Titanium dioxide is the most important and expensive pigment in paint formulations. Other minerals such as calcite and calcined kaolin are used as filler and mainly as a substitute for TiO2. Consequently, particle-particle interactions including adsorption, coating and size distribution of pigment mixture directly affects the paint quality. In the present paper, a new type of pigment mixture for possible use in architectural water based paints was developed through grinding. The effect of different types of grinding methods on physical properties of TiO2 and calcite mixture and the quality of paint produced by these mixtures have been revealed. Three different types of mills; conventional ball mill, vibratory ball mill and high-speed attritor were used for grinding of TiO2 and calcite. Viscosity, zeta potential and particle size distributions were used to characterize the pigment mixtures obtained upon grinding. The quality of paint was evaluated by standards based on both wet and dry paints such as viscosity, density, opacity and gloss. The paint produced with the pigment mixtures prepared in vibratory ball mill and high speed attritor showed improvement in physical properties particularly in the distribution and dispersion of mineral particles. Keywords: grinding, pigment, paint, TiO2, calcite

Sep 1, 2012

By Wedam Nyaaba, Edward Wellman, Angelina Anani, Eduardo Cordova, Sefiu O, Cluber Rojas, Adewuyi

This study aims to investigate the optimal method for ore pass construction in incompetent rock masses. We evaluated the conventional and raise boring methods based on safety, efficiency, excavation control and ground support for ore pass construction. A stability analysis using analytical Q-raise (QR method) and kinematic analysis methods for ore pass construction with a raise borer before and after grout injection of the rock mass was performed. As a case study, an ore pass (diameter of 3 m, depth of 100 m) within an incompetent rock mass was considered to gain further insight. The rock mass was characterized according to the classification methods Q Barton, rock quality designation (RQD), rock mass rating (RMR) and geological strength index (GSI). The grout intensity number (GIN) method of grout injection was used. The safety factor of less than 1.075 obtained before injection was lower than the acceptance criteria. However, grout injection before raise borer excavation resulted in a safety factor greater than 1.5. Using a raise borer without pre-grouting indicated that the maximum unsupported diameter (MUSD) of the ore pass was less than the required 3 m and equal to or larger than 3 m post-grouting.

Dec 1, 2024

By H. H. Schrenk

"One phase of the Bureau of Mines' work in the field of health and safety is the promotion of the use of safe, satisfactory, and reliable respiratory protective devices. To promote the development of such devices the Bureau has established schedules of minimum requirements for oxygen breathing apparatus3/ gas masks/, supplied-air respirators5/ (hose masks, airline respirators, and abrasive blasting helmets, hoods, or masks), and mechanical-filter respirators6/.Manufacturers of respiratory protective devices may submit their equipment to the Bureau for approval under the requirements of these schedules.As a prerequisite to such submittal, the Bureau requires a statement that the device is completely developed and of the design and material the manufacturer believes suitable for a finished marketable device; that the device has been subjected to inspections and tests such as described in the schedules, and that it met those requirements when tested by the manufacturer or his testing agency; and a. statement regarding the nature, adequacy, and continuity of control of the quality of the respirator. If the manufacturer can satisfy these requirements, and if the device, when tested by the Bureau, meets its requirements, a certificate of approval is granted by the Bureau of Mines. The approved devices bear distinguishing marks that indicate that they have been approved, the purpose for which they are approved, and the limitations of their use. If it is found at any time that approved devices purchased in the oven market and tested do not meet the requirements of the schedule, the Bureau may rescind that approval. Lists7/ of approved devices are published periodically for the convenient information of the public.Respiratory equipment may be divided into two main groups: (1). Those that afford protection by removing atmospheric contaminants and (2) those by which a respirable atmosphere from an uncontaminated source is supplied to the wearer.The devices that protect by the removal of contaminants may be divided into two subgroups: (1) Those that protect against gaseous contaminants and (2) those that protect against particulate matter. There may, of course, be combinations of these two.The devices by which a respirable atmosphere is furnished to the wearer also may be divided into two subgroups: (1) The self-contained type, by which the supply of oxygen, or material from which the oxygen can be generated is carried by the wearer, and (2) the hose type, by which air is supplied to the wearer through a hose or tube."

Sep 1, 1939

By C. F. Feng, L. Froyen

"In-situ processes have emerged as new and promising techniques for metal matrix composite fabrication. They offer significant technical and economic advantages over conventional processing. One of the in-situ processing routes that have been used is reactive free sintering of a mixture of powder reactants. However, materials synthesised via this route are always porous because of density differences between reactants and products. An example are the porous Al/(TiB2+Ah03) MMCs obtained by heating powder mixtures of Al+ Ti02+B with Ti02 and B in stoichiometric ratios for forming TiB2• In this study, porous Al/(TiB2+Ah03) composites were further processed by hot-pressing at temperatures above 600°C. This processing cycle was designed so that the composites could be densified. Furthermore, the reaction kinetics of the in-situ processing are studied by means of DSC analysis measured at different heating rates. The activation energies of the three intermediate steps that are involved in the reactive processing for preparing AV(TiB2+Alz03) MMCs are determined to be 923 kJ/mole, 241 kJ/mole and 235 kJ/mole respectively.XRD proved that the hot-pressed products consist of Al, TiB2 and Al203- Properties of the products are assessed by microstructural characterisation (LOM, SEM and EDS), microhardness, Young's modulus and bending tests. The results show that good microstructures, elastic properties and strengths, as well as acceptable ductilities were achieved. For the composition 79.74wt% Al-15.95wt% Ti0z-4.31wt% B, after the reactive free-sintering and hot-pressing cycles, Young's modulus is 105 GPa, bending strength is 509 MPa and maximum strain is 5.0%; for composition 88.73wt% Al-8.87wt% Ti0z-2.40wt% B, they are 89 GPa, 311 MPa and 8.2% respectively. It can be seen that the properties of products can be tailored by adjusting the relative amounts of reactants in green samples. Furthermore, for comparison reasons, Al and a binary system Al-Ti02 were identically processed as the ternary systems. Their microstructures and properties were studied."

Jan 1, 1998

By K. Saito, Y. Miyauchi, T. Nishi, Y. Kizu

At Tokushima Plant of Nippon Denko Co., Ltd. high-carbon ferromanganese is produced by the electric furnace method using lump manganese ores and sintered manganese ores manufactured from fine manganese ores. However, the distribution of manganese ores is significantly uneven on earth, and their characteristics considerably vary by ore type. It is known from experience that the production of high-carbon ferromanganese by the electric furnace method depends greatly on material ores. Therefore, to maintain stable operation in the electric furnace-smelting field, it is important to identify the characteristics of each type of material ores in advance. Thus, we evaluated the high-temperature electric characteristics of manganese ores using the electrical conductivity measuring system developed by ourselves and provided the standards for determining ores and blending ratio necessary for stable operation of the electric furnace based on the evaluation results. This time we worked for optimisation of the high-temperature electric characteristics of sintered manganese ores through modification of the characteristics because the blending ratio of sintered manganese ores in the electric furnace is high. The electrical conductivity of sintered ores having various chemical components in a high-temperature region (up to 1 550°C) was measured using our electrical conductivity measuring system and high-temperature electric characteristics evaluating method reported at INFACON 9. As the result of the measurement, we revealed that the high-temperature electric characteristics of the sintered ores depend on their chemical contents and the sintered ores can be modified to those having excellent high-temperature electric characteristics by controlling their chemical contents, so that the resources can be effectively used.

Jan 1, 2004

By J. Rabe

Tasked with developing a flow sheet for a new resource, one typically turns the experts for help. The advice of an expert can be invaluable in reducing the time and costs associated with characterizing an ore (not to mention extracting maximum information from limited samples). While guiding and optimizing a metallurgical concept study requires a certain skill set, selling a project is something different. The metallurgical specialist is usually not responsible for sharing the results of investigations with potential investors. However, the person responsible for selling the project can ensure that a metallurgical concept study is conducted thoroughly and responsibly without having the ability to do the work, while being sufficiently familiar with the metallurgical aspects to authoritatively sell the project. The process of identifying suitable process routes through to constructing a concept flow sheet and mass balance is discussed as a basic example. From basic mineralogical information and a thorough literature survey, the most likely beneficiation routes can be identified and targeted testing conducted. The final top size will depend on the required product properties (mainly grade), the selected beneficiation technology, and the ore?s liberation properties. Once the required top size has been identified, comminution options can be evaluated. Once again, literature surveys can be used to supplement concept-level comminution property information, and select possible equipment and circuit configurations. Marketing, material handling, and logistics-related information can be used to determine required dewatering technologies. At this stage, enough information is available to develop a concept mass balance and conduct basic equipment sizing..

Jan 1, 2014

By Qionghua Zhou, Wei Liu

"Nanocrystalline silver bulk material with average grain size of 20.3 nm was prepared by warmvacuum- compaction method. The as-prepared nanocrystalline silver was characterized by X-ray diffraction (XRD), differential scanning calarmeutry analysis (DSC), thermogravimetric analysis (TG), and 6157 type Electrometer test, respectivily. The experimental results show that the average grain size and microstrain of the nanocrystalline silver are 20.3 nm and 0.088%. The melting point and melting enthalpy are 1228.7 Kand 82.34 Jig, which are lower than that of coarse-grained silver by 6 Kand 22.6 Jig, respectively. The electrical resistivity of nanocrystlline silver increases with higher temperature when the range of temperature is between 233K and 293K. The electrical resistivity at 293 K is 1.475xlO -7 Q·m, which is higher than that of coarsegrained silver by a factor of 9.IntroductionN anocrystaline ( nc) materials or nano structured ( ns) materials are three-dimensional (3 D) bulk materials with average grain size typically smaller than 100 nm. Ne materials have been of great interest for their unique properties, such as superior tensile strength [1-2], high microhardness [3- 4], superplasticity [5-6], magnetically quasi-isotropic [7-8] , and so on, making them one of the most promising nano-scale materials with wide applications. Ne materials with average grain size of 5-10 nm were firstly fabricated by Gleiter et al. [9] in 1980s, using inert gas condensation (IGC) method. Unfortunately, the large surface to volume ratio creates a high surface energy component in the total free energy of the system and results in a metastable state in the materials. Therefore, due to the signfica nt disordered grain boundary regions, nanomaterials are thermally unstable and are subjected to a strong driving force for grain growth. The grain growth even occurred at room temperature [10].The conflict or deviation of measured date, e.g. strength, microhardness, thermal stability, partly due to the grain boundary ratio or the distribution of grain size, and partly derived from imperfections such as voids and microcracks while earlier processing techniques are known to result in incomplete dens:fication [11-12]. Therefore, the higher quality samples produced in subsequently years still show such a general trend."

Jan 1, 2011

By Mark A. Alspaugh, E. A. “Bud” Viren

The driving force behind most advances in technology is need. In the early 1980s, underground coal miners in the USA wanted to build longer conveyors to handle larger capacities but continue to use fabric reinforced belting with mechanical fasteners. Conveyors with intermediate drives were certainly the answer but achieving reliable designs required a significant learning curve. Basic design methodologies had to evolve including advanced simulation of starting and stopping along with complex control techniques and logic. Some components also evolved as specific performance requirements changed Today, in addition to underground mining, the technology has been used extensively in the tunneling industry where the need is for control of belt tensions to negotiate tight horizontal curves. Even though intermediate drives are not used extensively on the surface yet, the lessons learned will find their way to long overland surface conveyance where smaller components are more available and reliable, and often with less capital cost. This paper will document the evolution of intermediate drive technology over the last 30 years and will show examples of its current use.

Jan 1, 2004

By Shaw-Shong Liew

This paper presents the design concept using floating piles to support 2500Ton oil storage tanks on a very soft alluvial clayey soil of about 40m thick in Riau Province of Sumatra, Indonesia. The floating piles of various penetration lengths were designed to support seven numbers of such storage tanks seating on a 20m diameter and 500mm thick reinforced concrete (RC) circular raft. The pile points have been strategically located at the RC raft. Varying pile penetration lengths have been designed to minimize the angular distortion of the thin RC raft and the out-of-plane deflection at the tank edge. Vibrating wire strain gauges were installed at different levels inside the ø350mm prestressed reinforced concrete piles to measure the load transfer profile during the static load tests and water-loading test. The installation and interpretation of the instrumentation are described and discussed. Boreholes, in-situ tests like piezocones, vane shear tests and standard penetration tests, and laboratory testing were carried out to obtain geotechnical parameters for the pile designs. Static load tests were also carried out on the spun piles of varying lengths of 24m, 30m and 36m respectively. It has been demonstrated that the floating pile system can be a cost effective design to support heavy structures on very soft compressible deposits with satisfactory performance. Finally, the design concept validated with the results of instrumentation is discussed.

Jan 1, 2002