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By A. López-Valdivieso, M. A. Corona-Arroyo, M. Llamas-Bueno

Magnetite (Fe3O4) ore is concentrated by low-magnetic-field drums to recover a magnetite concentrate that is low in silica (SiO2). The presence of SiO2 in the magnetite concentrate for steel production increases the steel processing costs, so a major challenge in magnetic concentration is to lower the SiO2 grade in the Fe concentrate. This work presents studies that were carried out on the removal of SiO2 from the magnetite concentration at the plant scale. Studies were performed with a three 36 × 96″ drum unit processing 46 ton/h of rougher magnetite concentrate. These studies showed that silica appears in the magnetite concentrate by three mechanisms, namely SiO2 entrainment in Fe3O4 chains, heterocoagulation between Fe3O4 and SiO2 particles, and mineral locking of SiO2 to Fe3O4. The SiO2 entrainment mechanism had the highest contribution (75%) to the SiO2 recovered in the Fe concentrate. Electrokinetic studies on Fe3O4 and SiO2 showed that heterocoagulation occurs because of the low negative zeta potential of the minerals at the pH of the plant slurry. This study also showed that a high percentage of ultrafine size SiO2 particles trapped in Fe3O4 agglomerates was not removed by the dilution water for the slurry fed to the drum. To lower the SiO2 recovery in the drum magnetic concentration process, work should be directed towards the removal of trapped SiO2 in Fe3O4 agglomerates.

By Paul Wellman

The energy problem of the U. S; was emphasized by the oil embargo of late 1973 and early 1974 and it seemed for a time that the Federal Government, under pressure from the general public, might take some corrective action. However, this was not the case. With the gasoline lines gone and an apparent plentiful supply of petroleum products, public concern quickly dissipated., This country is more vulnerable to an oil embargo today than we were in 1973-1974 and this fact should be of concern to all our people. Since 1968, we have used oil and natural gas at a much more rapid rate than we have been able to find new domestic sources; thus, there is an increasing gap between domestic production and consumption and we have filled the gap with ever increasing oil' imports. These imports have increased at an alarming rate in the recent past, some 58 percent in 1976 compared with 1975. Imports are nearing 8 million barrels per day. Then, by applying some simple arithmetic, at $12 per barrel, the resulting trade deficit is $96 million per day or $35 billion per year. Obviously, this cannot be tolerated by our economy over a long period of time. Historically, we have shifted from one fuel to another as is shown in this slide. In 1850 about 90 percent of our fuel requirements came from direct combustion of wood, by 1900 we shifted to coal for 70 percent of our fuel, and now about 78 percent of fuel requirements comes from oil and natural gas. The difference is that the previous shifts were voluntary and the one facing us now is of necessity.

Jan 1, 1977

By Koehler Stout

Stopewall or room closure can be a problem in nining operations. In some mines, wall closure causes ore passes and nanways to collapse when they are enclosed in nine fill. When this phe- nomena occurs, heavy ground and, or, rock bursts frequently happen. Often, ground problems become progressively worse as mining in the stope block progresses toward the upper level. The sill and pillars in the level above may experi ence heavy ground and bursts. Sometimes the conditions get so bad in the stope that it is unsafe to mine the ore, so the stope is abandoned and the ore is lost.

Jan 1, 1980

By J-P Strydom, J P. Z, S. Schafrik, M. Beck, Z. Agioutantis

Developing a method to accurately determine the weight and distribution of the load within a shuttle car bed eliminates the need for manual activation of the flight chain. Accordingly, this experimental study characterized the thermo-mechanical response of two unique load cells in force shunt, implemented as an engineering control to quantify load position and distribution without human intervention. The influence of environmental and installation conditions on the measurement accuracy was quantified and determined to be indirectly dependent on the characteristics of the material load cells that are mounted to.

Feb 22, 2026

By Cleland N. Conwell

The term "tender tundra" is a myth---a well-developed myth, but contrary to the fact. Any area that supports herbivores must have a plant base to supply food, In Alaska, herds of caribou migrate and live north of the Arctic Circle. And, if there is enough growth in the moss and lichens and arctic grass to support a caribou herd, the "tender tundra" can heal after it has been disturbed by mining. Another myth is that Alaska is an ice box. Actually, many areas In the state---particularly the Interior---have a high agricultural potential. Nevertheless, the fact remains: whether it is reclaimed by advancing the productivity from forest to agriculture or is allowed to remain a wild-life habitat, Alaskan land will revegetate. Reseeding speeds reclamation, but left to nature, native species will reclaim the land whether it was disturbed by forest fires, roads, villages, or mining. In fact, it is impossible to find many of the old gold mining camps.

Jan 1, 1975

By Michael McNinch, LaTasha R. Swanson, Jennica L. Bellanca, Justin Helton

Accident data indicates that mobile haulage poses a significant pinning, crushing, and striking risk. Proximity detection systems (PDSs) have the potential to protect mineworkers from these risks. However, unintended consequences of mobile PDSs can undermine the safety benefit they provide. Soliciting iterative user input can improve the design process. Users help provide a critical understanding of how mobile PDSs may hinder normal operation and endanger mineworkers. Researchers explored users’ perspectives by conducting interviews with mineworkers from seven mines that have installed mobile PDSs on some of their haulage equipment. Mineworkers reported that mobile PDSs affect loading, tramming, section setup, maintenance, and general work on the section. Mineworkers discussed the operational effects and increased burden, exposure, and risk. Mineworkers also suggested that improved task compatibility, training, logistics, and PDS performance might help address some of these identified issues. This paper also gives additional insights into mobile PDS design and implementation.

By J. Weinstein

New erosion, corrosion resistant metal, ceramic, and polymer composite technologies are being developed and marketed by Alanx Products L.P. for use in hydrocyclones, pumps, valves, and other applications in mining and minerals processing. This paper will present an overview of the ceramic/metal composite material system and properties developed, which include excellent erosion/ corrosion resistance. Wear data will be shown from a variety of laboratory tests in dry and wet conditions, in aqueous neutral and corrosive environments. Comparisons will be made with a variety of competitive materials currently used in the industries sited. Data will also be presented on field tests with pumps and hydrocyclones in hard rock mining and other abrasive/corrosive environments. Field data from North and South America, as well as Australian mining applications will be highlighted.

Jan 1, 1992

By Paul H. Johnson

Chemical mining may be defined as the in-place extraction of metal values from ores located within the confines of a mine (that is, broken or fractured ore, stope fill, caved material, or ores in permeable zones) or ores located in dumps, prepared ore heaps, or tailing ponds. The term solution mining has, in general, been used to mean the in-place dissolution of water-soluble mineral salts with leach solutions. Chemical mining is presently in its embryonic stage. Basic research needs to be done to understand the influence of physical and chemical factors in chemical mining, and applied research needs to be done on both a small and a large scale to develop practical techniques of field practice. The areas of research include the following: (1) Leaching chemistry, the influence of physical, chemical, and biological factors in in-place leaching (2) Hydrodynamics of chemical mining systems (3) The development of new, as well as old, leaching agents for use under chemical mining leach conditions (4) The development of new means of contacting fine and coarse materials (with solutions) under static leach conditions (5) The development of new processes for generating and regenerating chemical mining leach solutions (6) The development of metal recovery processes

Jan 1, 1969

By Michael H. Inglis

The Technology Application Center, in conjunction with the U.S. Bureau of Mines Liaison Program, is studying the use of Landsat data for the monitoring of coal surface mine reclamation activities. Landsat may provide sufficient information to reduce the number of on-site inspections now required. The focus of the project has been the Navajo Coal Mine located in north- western New Mexico and operated by Utah International, Inc. On October 15, 1977, a field team recorded spectral measurements at the mine during the time of Landsat's overpass and a corresponding aerial photographic flight. Training sets were selected from the ground and aircraft data representing vegetated, graded, ungraded and natural environments. A supervised classification of the data was performed by the Stanford University Remote Sensing Laboratory then correlated to aerial photos and mine maps. The results, to date, have been very encouraging.

Jan 1, 1979

By C. H. Grant

The Dew Chemical Company has been engaged in explosives research since 1953. The incentive for this research was based on the desire to find additional markets and uses for magnesium metal of which Dow is a heavy producer. The thermodynamic calculations for explosives incorporating light metals indicate energies approximately twice that of non-metallized explosives currently being used. Early in 1960, we acquired additional patent rights from independent inventors and decided to set up a development station at Virginia, Minnesota, to conduct a commercial testing and market evaluation program with this new product. The actual manufacturing of the explosive was to take place in the bore holes. Due to the complexities involved in controlling the manufacture of the explosive in the bore hole, performance was sometimes in doubt. Furthermore, our experience indicated that the metallized explosive systems could not be evaluated by the standard laboratory methods then being used, and it was necessary for us to look for more suitable research methods. Tests were conducted on several known methods for explosive evaluation. The most promising were the Navy underwater method for energy evaluation, and a modified Livingston crater method intended to compare explosive performance in rock. After shooting over two thousand charges of eight to 60 pounds under water and in taconites and granites with many types of explosives, we have developed a metallized explosive which is now being manufactured at a pilot plant in Virginia, Minnesota, and is being evaluated commercially.

Jan 1, 1963

By Abegail Endraca, Allan Sebastian, Andrew Raine, Allan Patdu

The project involves the construction of a new aqueduct tunnel by an Earth Pressure Balance TBM tunnel for the Novaliches-Balara Aqueduct No 4 (NBAQ4) project in Metro Manila. It comprises a 7.3 km long and 3.1 m internal diameter tunnel that can deliver up to 1,000 MLD of raw water and the tunnel passes under urban residential and urban populated areas adjacent to and along Commonwealth Avenue. A new reservoir intake structure was constructed in the La Mesa reservoir by a cofferdam and the TBM breakthrough connected the reservoir to the outlet surge shaft structure and the downstream pipe network system connecting to the Balara Water Treatment Plant. The TBM incorporated a double articulated head configuration to allow tight 80 m radius curves to navigate some of the difficult alignment considerations. The alignment passed very close to some existing foundations for MRT7 and needed to clear several tight curves to remain within government land ownership. The project excavated through the local Guadalupe weak rock formations and there was minimal ground movements observed as a result of the work.

Jun 13, 2023

By A. L. Slaughter

A mineral deposit has been discovered and explored sufficiently to establish the presence of ore in ?commercially marketable quantities," This is the point at which exploration ends and development begins, Of course, when the presence of commercially marketable quantities of ore are thought to be present the deposit had to be evaluated before this decision could be reached. If, on the other hand, it was thought that commercially marketable quantities of ore are not present, either more exploration has to be done or the project must be abandoned. It is this decision with which this paper is concerned, more particularly, the influencing factors behind this decision. The final question to be answered is: what profit can my company reasonably expect to make by developing this property and putting it into production? The answer must be expressed as a figure for final profit per ton, money which can be used to pay dividends or to build up cash reserves. Some acquisition cost has probably been paid and the exploration cost incurred at the time of decision, (abandonment or development). In addition to returning these acquisition and exploration costs, the deposit must pay development, mining, milling, capital expense of new plants and equipment, taxes, and various other related costs.

Jan 1, 1958

By D. I. Hoyer

A preliminary model has been developed for autogenous pebble milling using information obtained from studies on ball milling and SAG milling. The model treats the breakage as the weighted sum of first-order breakage of smaller particles by tumbling pebbles, non-first order breakage of larger particles which are too large to be nipped properly by pebbles, autogenouS fracture and chipping of larger lumps to form pebbles, and autogenous fracture and abrasion of pebbles. The model includes the effects of residence time distribution, classification through the exit grate, and a mass transfer relation which describes the accumulation of fine material in the mill. Example simulations are given, based on breakage parameters determined from batch grinding tests in laboratory mills. fracture breakage and abrasion. In the development of these preliminary mass balance equations it will be assumed that breakage by fracture is first-order, but this assumption will be modified later in the paper. It will also be assumed that the residence time distribution of a long autogenous mill can be described by an equivalent series of m fully-mixed mills, with a classification action imposed on the mill contents by the discharge grate. Size distributions are expressed as a v2 geometric series, numbered 1 for the top size down to n for the fines, or "sink" interval. If the holdup in the mill is W then the rate of breakage of material in size interval i is given by SiwiW, where wi is the fraction of material in size interval i, and Si is -the overall specific breakage rate of size i material (fraction per unit time).

Jan 1, 1985

By Edward A. Nowatzki

The purpose of this paper is to present an example of the application of a theoretically derived mathematical model for track-soil interaction to the evaluation of the mobility of large-scale mining equipment used in open pit operations. The model described by Karafiath and Nowatzki (1978) and presented in detail by Karafiath (1978) was used to predict the performance characteristics of four different bucket wheel excavators (BWEs) on rwo types of copper mill tailings at various moisture conditions. The BWEs considered In the analyses are two-and three-tracked continuous excavators. Most have boom-mounted rotating buckets and swinging side- or rear-discharge conveyors. The analyses were performed at the request of Dames and Moore for the Kennecott Corporation's proposed remining of selected tailings deposits at the McGill, Nevada, concentrator. The objectives of the analyses were to determine whether BWEs would have sufficient mobility In the tailings deposit to achieve satisfactory production rates, and TO compare the predicted performance of the various BWEs evaluated. Good qualitative agreement was obtained between the results of the theoretical analyses performed for the McGil1 operation and the actual performance of BWEs in two South African gold mine tailings impoundments.

Jan 1, 1980

By Fred Morelko, Michael Connelly, Brad L. Ricks

INTRODUCTION The $1.1 billion Bajo la Alumbrera Project, started up in 1997 by Minera Alumbrera Limited in the Catamarca Province of Northwestern Argentina, is the first large scale modern mining project to be developed in Argentina. Like many modern Andean mining projects, existing infrastructure was not available to economically transport the 875,000 tonnes of product per year. A variety of alternatives were investigated, including upgrading of existing roads and railroads, slurry pipelines, and combinations of these systems. The final system selected was to combine a 312 km slurry pipeline with an 820 km rail haul to a ship loading facility near Rosario. The concentrate pipeline crosses divergent terrain between the minesite at 2400 m elevation and the filter plant at 400 m elevation. The system selected represented the lowest net present cost alternative by a significant margin. BACKGROUND The Bajo Alumbrera deposit was discovered in 1947 by Professor Cetioni from the University of Tucuman. It is a large (>750 million tonnes) medium-grade (0.6%) copper deposit with high gold values (0.5 g/t*). The deposit outcrops, making it very suitable to modern, large scale, open pit mining techniques using 218 t trucks and 43 m3 shovels. Advances in gravity concentration of the gold helped to demonstrate the feasibility of the project in a study prepared by Fluor Daniel for Minera Alumbrera in 1994. The initial concentrator is the largest green-field concentrator ever constructed, rated at 85,000 t/d. Production will peak at 190,000 tonnes of copper metal and 710,000 troy ounces of gold per year, one of the top 10 copper and top 15 gold producers in the world. * Throughout this paper, the word tonne and abbreviation refer to the metric ton of 1000 kg.

Jan 1, 1998

By James D. Piper

In the summer of 1957,9 the University of California sponsored a World Conference on Prestressed Concrete in San Francisco to which were invited a number of Soviet engineers. While attending the conference, these engineers in turn asked the University to form a delegation of American engineers to visit the Soviet Union the following year for the purpose of studying Soviet advances in concrete technology. A six man delegation was formed, and the dates of the Russian tour fixed for May 10th through May 21st, 1958. Before arriving in the Soviet Union, the American Delegation attended the Third International Congress on Prestressed Concrete in Berlin. While there, we noticed that the delegation from the U. S. S. R. used displays and showed motion pictures of many construction projects which we later were shown in Moscow. Our delegation left East Berlin by Russian aircraft on May 11th, and arrived in Moscow that afternoon. We were met by our Russian engineer hosts from The Academy of Construction' and Architecture who made all subsequent arrangements for our itinerary. This Academy has no counterpart in the United States. It. does 40 per cent of all engineering-and scientific work in the building construction field and coordinates 60 per cent of that done by other Soviet agencies. Due to the prestige of the Academy in Russian affairs, our delegation was able to obtain a surprisingly broad picture of construction activities in Moscow and Leningrad in just ten days time

Jan 1, 1960

By Peter G. Dunn

Geologic studies during development at Copper Flat were directed at acquiring the information necessary in evaluating a low-grade porphyry copper deposit. In addition to the geologic mapping and core-logging of a typical exploration project, these studies included the following : (1) careful checks on the sampling and assaying (2) selection of representative samples used to establish the recoverable amounts of precious metals in the ore (3) examination of underground workings driven to provide samples both for metallurgical testing and for assay comparisons (4) evaluation of plant site and waste dump areas as non-mineral, including a placer examination of the taillngs disposal area (5) location of an adequate water supply. All these investigations were carefully documented to provide the necessary data both for the engineering design and, more importantly, for the feasibility studies required for successfully financing the project.

Jan 1, 1981

By Walid M. Abdellah, Soliman Abu Elatta A. Mahmoud, Hanaa A. Abu Khoziem

The high-grade Th-U-Y zone is one of the numerous mineralized zones found in the El Garra El Hamra hydrothermally altered syenites in southwestern Egypt. It is characterized by the thorium minerals thorite and thorogummite, which are closely associated with xenotime-(Y). This zone of mineralization is localized in the eastern part of the El Garra El Hamra hydrothermally altered syenites. This zone does not relate to the first phase of syenites that appeared on the surface but is linked to the other, hidden phase of the syenitic body. Additionally, the fluids responsible for the mineralization of this zone belong to the late-stage hydrothermal event as well as the fault action due to the fact that it had continued reactivations for a long period of time. The studied mineralized zone also contains ceriopyrochlore-(Ce),(Ce,Ca,)2 (Nb,Ta)2O6 (OH), fluorite (CaF2) and barite (BaSO4), which are found in considerable amounts, whereas apatite (Ca5(PO4)3F) and chromite (FeCr2O4) are rarely found together with Fe-oxi-hydroxides (hematite and goethite) with a minor amount of jarosite (KFe33+(OH)6(SO4)2). Finally, the main constituent mineral in the zone is the pseudomorph perthite in addition to quartz, which is found as deformed crystals. A technological sample was collected from this zone and was found to assay 4.62 weight percent thorium (Th), 0.37 weight percent uranium (U) and 3.12 weight percent rare earth elements (REEs). From the chemical and mineralogical composition of the studied technological sample, the leachabilities of Th, U and REEs were investigated using sulfuric acid (H2SO4) agitation leaching and pug leaching methods. The latter was found to be preferred under the conditions of 0.54 ton H2SO4 per ton of altered syenite at 110 °C for two hours.

By Norman F. Schulz

The technical excellence of separation achieved in a mineral concentration process, or any other process where two constituents of any kind are physically separated from each other, is expressed uniquely and quantitatively by the Separation Efficiency: ES = (R ? Rg) where R is the percentage of the valuable constituent and Rg the percentage of the waste appearing in the concentrate. The Separation Efficiency meets all the usual requirements of a true efficiency and is independent of the nature of the process used. It can be visualized as the percentage of the feed material that, in effect, actually undergoes complete separation while the rest of the feed is distributed randomly and unchanged into the two separation products.

Jan 1, 1969

By Paul R. Wieber

This paper describes the U. S. Energy Research and Development Administration's (ERDA) program to develop in situ coal conversion processes, especially gasification, he potential of this technology, the technical directions being explored, and the program strategy to carry the process concepts toward commercialization are emphasized. The geographic location of the U. S. coal resources and a market analysis are described. Commercially successful in situ coal processes could add over a trillion tons of coal to the U. S. coal reserves. The economics of these processes is compared with surface gasification independent studies show this process to be 25Z cheaper than surface gasification for Western coals. The major projects are briefly described. The Linked Vertical Well process is in the lost advanced stage and shows great promise. The last test produced a low-Btu gas averaging 171 Btu per standard cubic foot for average pro¬duction rates of 5.5 million standard cubic feet per day. The other projects are Packed Bed, Longwall Generator, and Steeply Dipping Beds.

Jan 1, 1977