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By Robert H. Robinson, Levent Ozdemir, Russell J. Miller

The paper summarizes an investigation into the applicability of mechanical excavation to oil shale mining; identifies available machine types that are best suited to various aspects of the mining operation; presents preliminary comments on the configuration of an "IDEAL" oil shale mining machine; and establishes the background information necessary for conceptualizing and evaluating new mining methods using mechanical excavation equipment. Conclusions are also presented as to the best currently available systems, as well as potential future systems.

Jan 1, 1983

By S. H. Ward, R. A. Barker

THE Juniper Prospect is in Carleton County, N. B., at approximately 46" 31' north latitude, 67" 20' west longitude. During the summer of 1955 an area in west-central New Brunswick was selected for aerial electromagnetic prospecting with American Metal Co.'s helicopter-mounted equipment. Generalized, small-scale government geologic maps had suggested that this area was located along the western border of the northeast-trending granitic backbone of northwestern New Brunswick and might be underlain by the Ordovician-Silurian sediments and volcanics that are the host rocks for the recently discovered sul-fide deposits of the Bathurst-Newcastle district. The helicopter electromagnetic equipment located an anomalous conductive area, coincident with a small aeromagnetic closure, about five miles west of the town of Juniper. Subsequently 30 mining claims (total area about 6600 x 8000 ft) were staked and company personnel conducted geological, geophysical, and geochemical investigations on the property. The claims and immediately contiguous areas were mapped geologically, and an area of about 2000 x 4000 ft was soil-sampled and also surveyed by ground electromagnetic and gravity methods. Finally six diamond drillholes, totaling 3500 ft in length, were drilled to test the anomalous conditions discovered by the several exploration techniques used. The discovery of base metal sulfides during drilling was a technical success for the exploration methods, but the quantity of sulfides was too small to be profitably exploited.

Jan 1, 1959

The lead concentration of flotation feed ore slurries is determined using two ?-ray absorption gauges mounted directly on a 6 in. diameter flotation feed pipeline. One gauge is a conventional "density" gauge using CS137. The other is a "lead-sensitive" gauge, which depends on the preferential absorption. by lead of 225 key y-rays resulting from Compton backscatter of CS137 y-rays.Gauge outputs are combined using an analogue computer the output signal of which is directly proportional to the lead concentration of the pulp. The accuracy of measurement of the pulp lead concentration is ± 3·6 per cent for ore slurries with lead concentrations in the range 0'07-0·16 g/c.c. and pulp densities 1.43-1.60 g/c.c.This paper sets out the development of the technique and details are given of the two experiments (1964, 1966) conducted in the plant at North Broken Hill Limited. The installation of the two-gauge system inthe plant during May 1968 is described. Details are given of the calibration technique used and the results obtained.

Jan 1, 1969

By T. A. Muhlare

"Large quantities of slag are produced every year and dumped on slag heaps around the world, posing a potential environmental threat due to contained heavy metals content. Slags are waste minerals produced during furnace smelting of minerals. The contained values of base metals may be released into the environment under natural weathering conditions polluting ground and underground water. Copper losses into slag are a continuous problem in pyrometallurgical smelting operations. Due to shortage of ore concentrate, various mining operations have initiated the recovery of copper from dumped slag. The typical process uses crushing, milling and flotation. These operations create excessive liner wear rates during crushing and milling because the bond work index of copper slag is 22 kWh/t and this is considered a very hard slag. The process also has reduced flotation recoveries and requires high flotation reagent consumption. The present work shows that digestion of the milled copper slag slurry with concentrated sulphuric acid at a temperature of 250oC forms a solid cake and leaching of the solid cake with water is a possible option. However, the consumption of sulphuric acid can have a considerable cost on the recovery process. This can be limited by producing a leach residue containing gypsum and silicate materials as amorphous silica which are suitable for use as an additive for Portland cement. Laboratory results show that 90% copper recoveries can be achieved. The leaching is conducted to prevent silica gel formation and iron co-extraction. Leaching is optimum if silica gel-free solutions and good filterable residue are obtained. INTRODUCTION Slag is a waste by-product of smelting and converting operations in metallurgical plants. Both smelting and converting operations are aimed at iron separation from base metal sulphides in non-ferrous metallurgy. The iron sulphide component of the ore or concentrate is oxidized to iron oxide at higher temperatures in the molten form, and then fluxed with silica and other oxide rock minerals to produce fayalite (2FeO•SiO2) slag (Schlesinger et al., 2011). Slags are generally deposited on dumps and considered to be unreactive materials. Smelter copper slag contains significant concentrations of several potentially toxic elements, including arsenic, lead, cadmium, barium, zinc and copper. These elements can be released into the environment under natural weathering conditions and cause pollution of soils, surface waters and groundwater (David, 1998)."

Jan 1, 2015

By Steve Kral

Led by a surge in coal production and prices in recent years, Colorado’s mining industry is taking part in the same revival as others states and the world. Not too many years ago, the state’s industry was languishing in the same doldrums as the rest of the mining world. Ironic for a state whose history was based on mining. Now, however, Colorado’s mining can boast increased production in all commodities produced, along with prices that allowed companies to expand, increase work forces and post improved shareholder value. So there was a lot of optimism at the Colorado Mining Association’s (CMA) 107th National Western Mining Conference in February. The conference, held in Denver, attracted more than 500 attendees and 39 exhibitors. The theme was Colorado Mines the World.

Jan 1, 2005

By J. Stephen Slottee, Jerold Johnson

The use of a thickener, without filtration, to produce a non-settling paste (also called thickened tailings) with non-Newtonian rheology has been practiced in Australia for many years for the disposal of red mud. The application of paste thickening technology outside of alumina is relatively new. Interest and installations in paste thickening are rapidly growing. Water shortages and environmental pressures make consideration of thickening tailings to solids concentrations within the paste range necessary in most new tailings projects. The paste thickeners at the DeBeers CTP plant in Kimberley, South Africa are the latest example of paste tailings disposal on the surface, also called “stacking”. Houman (2003) The use of a paste thickener as an alternative to filtration for mine paste backfill is a more recently developed application. This paper describes the principles of design and general operating characteristics of a paste thickener compared to the conventional and high-rate thickener. The application and operating performance of paste thickeners in mine backfill is discussed as an example. An integrated approach to process design is described that matches the performance of the thickener, pumping system, and application on a common rheological basis to ensure that none of these steps prevents achieving process performance targets.

Jan 1, 2005

Poorly designed sampling protocols generally result in high project risk by artificially increasing grade variability (ie the nugget effect). Sample collection, preparation and assay protocols that suit the ore type, together with QA/QC systems, will reduce this risk. All reporting codes (eg JORC, 2004) require the Competent Person to consider the quality and implication of sampling and assaying programs. High sampling errors beget higher project uncertainty; despite this fact, sampling does not receive the attention it deserves. The case studies presented show that many sampling issues frequently go unrecognised or unaddressed, resulting in poor project decisions during exploration through to feasibility and production. The overall conclusion is that correct sampling is critical to mining project success and that there is often a need for its optimisation.

Jan 1, 2007

By Brett Zernich, Michael Krulc, Brett Robinson

This paper provides an account of the efforts undertaken to construct the Northeast Interceptor Sewer (NEIS) project, which is a portion of a much larger program in Los Angeles, California to upgrade the city’s wastewater facilities. The project consisted of a number of elements, including both soft ground and rock slurry wall shafts, drilled shafts, soft ground EPBM mining, rock TBM mining, large diameter pipe placement, and underground structure construction. The need to complete the project under strict schedule constraints, in addition to the challenges of underground construction in congested urban areas, necessitated the work be undertaken with the proper balance of state of the art equipment, and thoughtful planning. The paper will detail the means, methods, and equipment used on the project, as well as discuss several of the unforeseen conditions encountered during construction.

Jan 1, 2005

The cost of power is an important matter to mining companies generally and this thought that the members of the Australasian Institute of Engineers, as well as the engineering and mining professions generally would be interested in any proposal for the reduction of that cost has led to the presentation of this paper.The writer trusts that the description will be found clear and increase the interest in this interesting subject. In the up of the electrical arrangements touched on in this paper, the author has had the able assistance of his friend Mr. Mars, to whom he offers his hearty thanks. The selection of the best class of power plant for a mine is a very difficult and large problem and it is quite out of place to dogmatise that anyone of the many systems that offer is better than another, eg that the all electrical is better than the partly direct steam-driven and partly electrical, or that a gas plant is better than a steam plant. Such a selection is one that calls for very careful and close consideration, in each particular case, of a large number of before it is possible to arrive at a proper decision.

Jan 1, 1912

By B. Kahraman

About 70% of the world?s total boron reserves are located in Turkey. Boron minerals are typically concentrated by attrition scrubbing followed by screening and classification to remove clay minerals and other impurities. These wet concentration methods, however, result in a considerable amount of accumulated tailings in large tailings dams. The tailings are approximately 28% solids and contain 14% B2O3. Problems caused by these tailings can be minimized by employing dry beneficiation techniques involving heat treatment. This method has been successfully tested on laboratory and pilot scales. During heat treatment, borax undergoes expansion in volume. The amount of expansion is dependent on the particle size, temperature and duration of heat treatment. Because the optimum temperature and the duration of the heat treatment are not well defined, the boron ore acts as a calcined clay mineral and is discarded along with the gangue. It is important to predict such parameters using mathematical formulations. Thus, a mathematical model is used to predict the required temperature and duration period prior to heat treatment. In the experimental study presented here, a series of systematic thermal tests was carried out in a muffle furnace. Two variables, temperature and time, were studied in a response surface design. A quadratic regression model was chosen and regression coefficients were calculated. Using a regression equation, the volume expansion of the particles in various circumstances can be predicted. The mathematical test results are then correlated with the experimental results to relate the optimum expansion of borax with heating time and temperature and with borax grades and recoveries.

Jan 1, 2008

By Robert Stefanko

With passage of the Clean Streams Act of the Commonwealth of Pennsylvania and its impact on the coal industry, considerable research has been conducted to explore various approaches to the problem, including deep-well disposal. Available drillhole data from gas and oil wells were used to develop cross -sectional maps for various portions of the state and potential disposal zones were evaluated. Bethlehem Mines Corp., faced with a severe water problem at its Marianna operation in Washington County, cooperated with the Dept. of Mining at The Pennsylvania State University in establishing a 1500-ft well into the Salt Sands for the purpose of determining the feasibility of mine water disposal. The thickness, porosity, and permeability of the formation at the well site proved to be below what had been anticipated from drillhole data. Further, subsequent hydraulic fracturing did not improve the flow characteristics of the well; pumping pressures remained in the range of 1800-2000 psig for disposing of water at the rate of 150 gpm. The legal problems of disposal at the site were very formidable. When the Salt Sands proved to be less than satisfactory, permission could not be obtained to dispose in other promising formations. The paper details many of the problems associated with the experimental well and makes an assessment of the potential for deep-well disposal of mine water. The concept of disposing of liquid industrial wastes by deep-well injection is not a new one. Brines associated with crude oil long have been disposed of in this manner, with the additional benefit of aiding secondary oil recovery. More recently, with the expansion of nuclear energy, the lethal, highly radioactive wastes which are by-products of the fission process have created severe disposal problems. During the past ten years, a variety of industries have resorted to subsurface disposal, some of the details of which are given e1sewhere.l,2 The list reveals wide variations in injection rate, pumping pressure, cost, and waste disposition. Included are successful installations in Western Pennsylvania. Enactment of more restrictive clean-water legislation in Pennsylvania recently had a great impact on the coal industry. Among its provisions was the reclassifica-tion of most mine water as industrial waste whose dis-posal is prohibited in any stream of the Commonwealth. This had the effect of accelerating research in a variety of areas, although treatment methods still retained primary interest. When a feasibility study of deep-well disposal was proposed to the Pennsylvania Dept. of Mines and Mineral Industries, the Coal Research Board (CRB) approved it. This paper summarizes the efforts on this project. Acid mine water is a chemically complex liquid. having no definite quantitative relationship among its constituents. However, it is the iron disulfide (FeS2) associated with practically all coal seams that produces the objectionable products present in acid mine water when combined with air and water. The principal contaminants are sulfuric acid (H2SO,) and ferric hydroxide (Fe(OH)2. Ferric hydroxide is a rust-colored gelatinous precipitate that coats stream bottoms and destroys aquatic life. However, other ions and bacteria are present in acid mine water in varying amounts.

Jan 1, 1971

By Jarek Jakubec

The new euphoria in diamond exploration brings with it a need to understand the challenges that new projects can face in different stages of the development and risks that the commercial outcomes from the new projects fall short of expectations. In many cases, the problems are related to a poor understanding of the technical risks and a failure to adequately address them during the course of investigation. Failure to evaluate all disciplines to the same level of certainty could lead to a situation where the important issues are only identified late in the project development, resulting in costly delays and financial difficulties. The diamond projects located in Canadian Arctic, with its challenging environmental, geographical, social, political and geological contexts are especially sensitive to the high variability of the outcome. This presentation highlights some of the technical aspects that could be the leading sources of risk in diamond projects and could ultimately result in inappropriate mine designs, reducing the economic outcome.

May 1, 2006

By Mike Muchard

Augered cast-in-place piles are one of the most cost effective deep foundation options available to designers but have been largely underutilized due to skepticism associated with quality assurance and hence capacity. When installed correctly, unit friction values can rival any other competing foundation system. To this end, many means have been implemented to increase confidence in the competence of the foundation. One such method is load testing via the Statnamic test method. This paper presents an overview of the Statnamic test method, advantages and disadvantages of its use, and several case studies where Statnamic testing of augered cast-in-place piles confirmed quality construction, brought about design changes, or proof tested problematic installations.

Jan 1, 2000

By Varadarajan Seshadri

Geometallurgical characterization of iron ore which is a raw material for Iron making as in the case of charcoal blast furnaces operating in Brazil or for production of agglomerates such as iron ore sinter which serves as burden material for blast furnces of high productivity or pellets extensively used in the direct reduction processes all over the world in the iron and steel industry. Selection of proper raw material after due characterization should lead to an improvement of the productivity of the respective processes The usual classification of quality of iron ore is uniquely based on chemical analysis, granulometric and physical parameters. However not much emphasis has been given to the structural characteristics which also are important in the processes. Different typological categories of Brazilian iron ores have been used in the characterization . For instance, several kinds of hematite crystals like specularite, martite and microgranular hematite, etc with variable crystal sizes are found in the different ore types. They are also composed of different of fabrics and types of accessorial mineralogical constituents and have different porosities, pore diameters, etc which influence the cold and the hot agglomeration stages of the ore fines, and also chracteristics such as reducibility, decrepitation etc, important for assessment of quality of iron ores. . The first step for attaining a good characterization of ores is to know in detail about the structure of the deposit, shape of the body, types of iron ores and their distribution. This requires a geological-structural study and the mapping of the bodies using mineralogical criteria for typological classification of ores. followed by structural characterization of materials in stages of mining, comminution, screening and concentration processes. In this contribution a geometallurgical approach for quality control of Brazilian iron ores for sintering and pelletizing processes is highligted.

Jan 1, 2006

By S Hapugoda, J R. Manuel, M J. Peterson

Microindentation testing using the square–pyramid–shaped Vickers indenter is a well-established technique to determine the microhardness of minerals and materials. However there is a paucity of published microhardness data from Fe ore samples. It is acknowledged that an iron ore’s particle mineralogy and texture is critical to its processing properties, and it is therefore considered that the microhardness of different mineralogical/textural types may also relate to these properties. Mineral microhardness potentially provides inputs to the modelling of breakage characteristics during comminution, as well as the relationship between mineral chemistry and microhardness, and mineral microporosity and microhardness. Microhardness can be determined as single crystal microhardness, for more coarsely microcrystalline samples, or as ‘aggregate microhardness’ for cryptocrystalline or finely microcrystalline samples.Variations in the texture and mineral chemistry of common Fe ore minerals (eg martite and microplaty hematite, ochreous and vitreous goethite etc) are well established and this study provides microhardness data on different textural forms of Fe (oxyhydr)oxides from a variety of different Fe ore deposits. The data indicated that in general, the mineral grain size, microporosity and texture were the main influences on Fe (oxyhydr)oxide microhardness. There were no apparent systematic variations between microhardness and minor element mineral chemistry, with the possible exception of Al content in goethite (for goethites with Al content >0.5 wt per cent), and for goethite total element contents >90 wt per cent (determined by electron probe microanalysis, EPMA). Higher Al concentrations and lower total element concentrations in goethite EPMA analyses correlated with lower goethite microhardness. Microporosity and grain size were more important than texture to hematite microhardness. Different textural forms of dense hematite (eg martite, recrystallised interlocking hematite and specular hematite) with similar grain size exhibited comparable microhardness. Microhardness values for hematite and hydrohematite with little or no evident microporosity were also similar, whereas more porous forms of martite, microplaty hematite or hydrohematite exhibited lower microhardness.CITATION:Peterson, M J, Manuel, J R and Hapugoda, S, 2017. Microhardness testing of hematite-goethite Fe ores – implications for their textural characterisation and geometallurgy, in Proceedings Iron Ore 2017, pp 319–330 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 24, 2017

By Eder Salazar

Como parte del desarrollo de sus operaciones de mina de cobre subterránea, la Sociedad Minera El Brocal S.A., desarrolló el método de minado tajeo por subniveles con pilares recorridas con el fin de incrementar su producción actual. En ese sentido, el presente texto señala la implementación de un método de minado conforme a las características geomecánicas del macizo rocoso del yacimiento.

Sep 12, 2011

By Alfred Weiss

These volumes report on the study initiated by the U. S. Bureau of Mines to develop and apply a methodology to quantitatively assess the probability and potential benefits of technological innovation over the next twenty-five years. The potential was recognized for new technology to solve copper industry problems in the United States. Objectives of the study were to: (1) Develop a methodology to obtain the opinions of mineral experts about future events -their likelihood of occurrence, and, conditional on occurrence, when and to what extent they are likely to occur; (2) Identify, select, and describe potential technological innovations which would have significant impact on copper production; (3) Implement the methodology and obtain the opinions of the mineral experts regarding selected copper technologies; and (4) Analyze the expected future benefits of successful technological innovations :n the copper industry. Although individual technologies are continuously examined throughout the copper 'community', this study is the first known comprehensive forecast of future copper technology. This study is also believed to be unique 1n that it represents the consensus opinion of over sixty expert copper technologists on the expected use of innovative technology in the industry over the next 25 years. The report is contained in three volumes.

Jan 1, 1983

By R. A. Harris

In this study Pt-Al thin films were prepared via electron beam physical vapour deposition (EB-PVD) with an atomic concentration ratio of Pt25:Al75. These films were heat treated at temperatures ranging from 150°C to 650°C for annealing times from 4 to 60 minutes. The resulting microstructure of these thin films were obtained via secondary electron imaging used in conjunction with depth profiling with the aid of scanning auger microscopy (PHI 700).Elemental maps of the micrographs were obtained. Simulations, based on a chemical potential Monte Carlo method1, were run for various interaction parameters. From these simulations theoretical depth-profiles and proposed microstructures were obtained. These were compared to the experimentally measured depth profiles and elemental maps. Keywords Monte Carlo, chemical potential, depth profile, Pt-Al thin films.

Jan 1, 2011

The 21st Annual American Mining Hall of Fame Awards Banquet sponsored by the Mining Foundation of the Southwest will be held at the Sheraton Tucson Hotel in Tucson, AZ on Saturday, Dec. 6, 2003. This year’s inductee, guest of honor and featured speaker at the banquet will be Thomas J. O’Neil, recently retired president and chief operating officer of Cleveland Cliffs Mining. Prior to Cliffs, O’Neil spent 10 years with Cyprus Minerals. He was also professor and head of the Department of Mining and Geological Engineering at the University of Arizona. As representatives of mining heritage, the Hall of Fame will induct James Boyd and Thomas F. Walsh. Walsh discovered a rich gold telluride vein in Ouray, CO, which became the Camp Bird gold mine. Boyd was a former director of the U.S. Bureau of Mines, vice president of Kennecott Copper and later president of Copper Range.

Jan 1, 2003

By J. Bertisen, G. Davis

Previous analyses of small samples of mining projects have found that feasibility studies tend to well under-estimate the actual capital costs of the project. Our review of 63 mining and smelting projects completed over 4 decades confirms that as-built capital costs are, on average, 25% higher than as estimated at the bankable feasibility study stage. There appears to be little attenuation over time of this bias in capital cost estimation, at first appearing to reflect an absence of learning on the part of the consulting engineer. We instead argue that this persistence of bias is intentional, driven by a scarcity of project financing and the need to inflate the project economics in a bid to secure financing. Around this intentional bias is a considerable amount of scatter. Roughly half of all projects’ as-built capita costs fall outside of the expected ±15% of the feasibility study capital cost estimate, even after allowing for intentional estimation bias. Cost overruns of 100% or more happen in roughly 1 out of 13 projects. The data reveal that a shifted lognormal probability distribution should be used when modeling mining project capital costs in a Monte Carlo analysis.

Jan 1, 2007