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By G. A. Koenig, Moritz Stockder

Locality and Geological Occurrence.—The Atpine region of Southwest. Colorado. cort~prieiog the San Juan and Uncon~paghre Mountains, is con~posed of a deeply eroded sheet of acid eruptive rocks, overlying in part gneissic schiets, and in part limestones and sandstones, including portions of the Silurian, Devonian, arid Carboniferous systems. The section is clearly and beautifully exposed along the Uncompghre River from its headwaters to its exit from the mountains. The river's course from the town of Ouray towards the Los Pinos agency is due north, and four miles from Ouray, in this directiou, the Uocampaglire receives from the east the Red Casm Creek. Following up the narrow canon we find the section through white. sandotone in strata dipping to the north and west, and belonging either to the lower or middle Devonian system. Presently the steep cafion-like character of the ravine gives place to more gentle slopes, ad we have entered crysralline rock—porphyry. The contact is well marked, for the sandsbne, to a depth of from six to ten feet, resembles quartzite, i. e., is serui'fusd. Ascending still higher, a small

Jan 1, 1881

By Francesco Chiappalone, Marco Invernizzi, Franco Gasperin, Brad Yoder, Fabrizio Fara

The Ship Canal Water Quality Project includes a 2.7-mile, 18-ft and 10-in internal-diameter tunnel that extends from Ballard to Wallingford, two popular neighborhoods in the West of Seattle. During the TBM Main drive a 12' × 12' boulder with variable strength up to 47,000psi was encountered resulting on signicant damages to the Cutter ead. The rst part of this paper describes the design and construction of an underground recess in front of the TBM to create a safe working environment for the TBM repairs. The second part describes an injection campaign performed to seal an unforeseen water inow appeared during the excavation of the 11 Avenue Diversion Structure.

Jun 23, 2024

By Michael G. Nelson

In 1992, the Alaska Department of Environmental Conservation received a grant from the Environmental Protection Agency (EPA) to fund the reclamation of an abandoned placer mine. The project also included the development of a water-quality and hydrologic-monitoring program. The grant was provided under Section 319 of the Clean Water Act and is administered through EPA's Region X Water Division. For the past 100 years, Alaska's interior has been the site of extensive placer-mining operations. Early surface and underground operations left small tailings piles, some of which are still visible. Dredging left larger tailings piles, similar to those in California and elsewhere. The only reclamation of these tailings involved use as road base and fill and other civil applications. Most active mines in Alaska are on state and federal lands. The standards of reclamation for mines on federal lands are established under US Mining Laws, 43 CFR 3809. They address only mines operated since 1981. Under a state statute passed in 1990, the Alaska Department of Natural Resources, Division of Water and Mining, has issued reclamation regulations. These regulations apply to sites on state, federal and private lands, but only those mined since Oct. 15, 1991.

Jan 1, 1995

By M. M. Veiga, M. Koehoorn

This paper reports on recently completed research that investigated the health fabric of mining communities in British Columbia (BC), Canada. The project, funded by two national funding agencies and the BC Government, and supported by numerous provincial organizations, marked a collaboration between mining engineering and health researchers. The study employed mixed-methods. First, a quantitative phase merged census, mining industry and health data to investigate the relationship between declining economic conditions and health outcomes (mental illness and stress-mediated cardiovascular disease). Second, a qualitative phase investigated community health issues associated with the mining boom-bust cycle from the perspective of health and social service providers working in a northern BC coal mining community. Third health research findings were disseminated to potential knowledge users in the hope of enhancing mine impact assessing and integrated mine planning. The paper provides a synthesis of the research methods used in this project, and highlights the main indicators used and key findings. It concludes by identifying recommendations, and future research needs considered to be of particular importance to the health and sustainability of mining communities in BC, Canada and around the globe.

Jan 1, 2011

By Serge Vézina

Environmental issues have evolved considerably over the last two decades. The main contributing factors, to name a few, have been the changing values of our modern societies, the globalization of trade and its linkage to environment, evolution and accessibility of information/communication technologies, better educated populations, climate change, long range transport of toxics and the increasing influence of NGOs and multistakeholders. As well, environmental management of mining operations had to be realigned in order to meet these new realities and to respond to more elaborated regulations oriented towards sustainability. Environmental Management Systems (EMSs) have emerged and have been introduced to meet not only the assurance of conformance to regulations but also to prevent pollution and to apply the continuous improvement of mining processes. EMS models have been developed and certification to international standards (e.g. ISO-14 001) is a common practice. Globalization has imposed challenges and additional requirements to environmental management. Developing a mine in emerging countries implies dealing with international agencies, local communities and a variety of government infrastructures to obtain a ?licence to operate?. This paper presents the structure of our EMS and how we have adapted its implementation to our operations in South America.

May 1, 2003

Adsorption Effect on Multi-Heavy Metal Ions in Wastewater by Water-Washing Waste Saccharomyces cerevisiae

Sep 13, 2010

By Leonard Obert

This report describes a gage which, when used with my procedure for producing strain relief, will measure the resulting borehole deformation, From the borehole deformation the magnitude and direction of the principal stresses in a plane normal to the axis of the borehole can be calculated. The design considerations, mechanical construction, sensitivity, and stability of the gage are discussed. INTRODUCTION During the past two decades an increasing mount of consideration has been given to the problem of measuring and evaluating stress in rock around underground openings. Several investigators have made theoretical and model studies of the stress and (or) strain concentrations around simulated mine openings or in structural members, such as mine pillars or immediate roof. Other investigators have developed gages for directly or indirectly measuring stress or strain, and a number of reports present the results of measurements made with these gages. Because various methods and instruments have been developed, factors involved in this type of measurement will be briefly considered.

Jan 1, 1962

The Geological Survey of the U.S. Department of the Interior is primarily a domestic agency whose responsibility is furnishing impartial data and analyses to the public, private, and academic sectors of the Nation. The Survey concentrates on earth-science issues, such as mapping the land surface, determining the quality and quantity of water resources, estimating the nation's endowment of fuel and nonfuel minerals, and predicting and mitigating geologic hazards, such as those inherent in the tectonically active Pacific Rim. One of the challenges to managing this program is striking a sustainable balance between concentrating on the problems society wants solved today and investing in the research that seeds our vitality for the future. The Geological Survey's role in the Pacific results from the Nation's geography and the Nation's long standing interest in and commitment to the region. The longest segment of the U.S. coastline borders the Pacific Ocean, one of our states is a Mid-Pacific island chain, our lands are 80 degrees--nearly one-fourth--of the Pacific perimeter, and our Exclusive Economic Zone (EEZ) underlies significant parts of the eastern, northern, and central Pacific waters. Thus, the program of marine and terrestrial science operating in these areas make substantial contributions to the world's growing understanding of the Pacific realm.

Jan 1, 1990

By A. D. Davis, C. J. Webb

Brohm Mining Co.'s Gilt Edge Mine in the northern Black Hills was a surface heap-leach operation that was active from the 1980s until 1999. Financing problems and acid drainage concerns at the mine were reported in the late 1990s. In February 1999 the Governor of South Dakota announced plans to request the US Environmental Protection Agency to help clean up acidic water at the mine and reclaim the site. In July 1999 the parent company of Brohm, Dakota Mining, filed for bankruptcy in Canada. Because of the bankruptcy and environmental problems, the State of South Dakota intervened and began water treatment. The mine was declared a Superfund site in 2000. Hydrologic issues include the potential for acidic drainage from the site. The mine is at the headwaters of Strawberry Creek, which drains into Bear Butte Creek. About four miles downstream, Bear Butte Creek loses its discharge to swallow holes in the karstic Madison Limestone aquifer, a regionally extensive and valuable groundwater reservoir. Other concerns at the site include treatment of acidic water in mine pits and a waste rock dump.

Jan 1, 2003

By Joseph Grumer

About a century ago Bunsen and his associates invented the famous burner that bears his name and was to become the ancestor of today's gas appliances. Over the years, Bunsen's invention became the starting point of a highly developed, practical technology that culminated in the gas industry as we now know it. However, it did not occur to the early workers to investigate the scientific potentialities of the new device, and as a result the science of gas-burner performance did not keep pace with the growing industry. It was with the objective of closing the rapidly widening gap between science and technology that the present research was undertaken Its immediate purpose was to provide basic information on the combustion characteristics of .fuel gases, in particular as they affect flashback, blowoff, and yellow tipping. Information obtained in the present research and contained within this report consists of the following: (1) Fundamental flashback and blowoff characteristics have been determined, it is believed, for all fuel-gas mixtures in which the gas industry may be interested. These are critical boundary velocity gradients for flames in free air, on burners with ports at room temperature and pressure. Burner aeration is characterized by the parameter, fraction of stoichiometric. These basic limits are explained, values are presented, and calculation procedure is given for deriving corresponding values of port loading and percent primary air (chs. I and II).

Jan 1, 1956

By K. C. Naidoo

There are two main types of densifying cyclones currently available in the market, namely polyeurethane (PU) and ceramic. The PU densifying cyclones are currently used throughout the Grootegeluk complex and coal beneficiation in general. It has been identified that PU densifiers wear relatively fast depending on the operating pressure and need to be replaced frequently as a result. The motivation for this paper is to achieve an increase in the densifying cyclone lifetime through less wear and an increase in efficiency resulting in the ability to build higher relative densities (RD) more quickly. This will allow for a reduction in downtimes due to replacing densifying cyclones as well as building RD and a reduction in the operating costs associated with replacing worn densifying cyclones. Some of the major findings of the study indicated that the ceramic cyclone theoretically undergoes less wear than the PU cyclone, but since wear is application-specific and was evaluated, the wear on the polyurethane cyclone was found to be minimal. The RD differential is higher on the PU cyclones than the ceramic cyclones, showing that the PU cyclones perform better in a densifying application. This is the first test conducted on this application and type of cyclones. It should therefore be noted that having the PU cyclone significantly outperform the ceramic cyclone was not expected, due to the only change being the material of construction. This is an indication to take the material of construction into account when selecting cyclones as it can have a significant impact on the cyclone performance in specific applications. Keywords: Ceramic, cyclone, densifying, density, dense medium, polyurethane, wear

Jan 1, 2020

By Stefan Mutl

By the term sorting one understands the separation of a material mixture into two or several products according to different material characteristics in the preparation technology. The oldest sorting procedure, the handpicking, is less and less used to separate different material mixtures because of the considerable personnel expenditure and the strict hygienic regulations at the workplaces in Europe. In general, the manual assortment is able to solve separation tasks, which could not be solved by machines so far. The picking is one of the most selective processing methods. However, the progress in the computer and sensor engineering today makes the creation of automatic picking devices possible, whose efficiency goes far beyond the possibilities of handpicking. Therefore in the future automatic picking will not only be applied to already common applications like the waste glass assortment by colour, but also to the assortment of complex composed material mixtures e.g. old shreddered cars. Thus, the automatic picking, supported by high performance computer systems and new sensor technology, gains more and more significance within many applications of waste processing. However, in order to apply automatic sorting procedures for different material streams within recycling processes, a substantial research and development need still is existing. The desire of the users is to sort more extensively in order to achieve products with bigger material varieties, In addition, the requirement of the accuracy of recognizing and sorting out of single grains rises, This lecture illustrates the procedure of the hand picking before it was employed in waste processing. Thus, a renaissance of a long forgotten method is happening in terms of today's state of the art procedure "automatic picking". Possible technologies, fields of application and future potentials of this technology are pointed out.

Jan 1, 2003

By J Wall

The use of electronic detonators in civil tunnelling applications, to reduce vibration in small firings has been successfully utilised for a number of years. As part of the mining industry’s commitment to reducing blast damage during the development cycle in underground mining applications, a series of development blasts using e-Dev™ electronic detonators in a typical mining application was conducted at Resolute’s Mt Wright operations in North Queensland in 2010. Results were based on direct comparisons to the current industry standard of non-electric firings as a baseline, with as many parameters as possible being captured during the trial. Development costs are typically high in most underground mines, especially in capital development headings, which are in waste and therefore of no direct economic value, so by being able to accurately fire to design, costs relating to both ground support requirements and volume of material removed, (and therefore haulage required) can be minimised. A direct comparison of overbreak (ground blasted outside of design) and cast (distance rock thrown from blast) was also made during the trial, as well as close monitoring of the drilling accuracy.

Mar 21, 2011

By J. H. Corrigan

A series of six papers describing the Falconbridge Dominicana Ferronickel project were presented at the International Laterite Symposium held as a joint project of TMS-AIME in February 1979 at New Orleans. A review of the ore mineralogy, as well as. the processing and environmental practices as they exist today at Falcondo with emphasis on modifications put into practice since 1979 are presented in two papers: Part I.- Mineralogy and Ore Dressing E.W. Lithgow - General Superintendent ? Mines Falconbridge Dominicana, C. por A. Bonao, Dominican Republic Commercial volumes of nickeliferous laterite ores overlie part of a 90 km long belt of peridotites in central Dominican Republic. Protores are serpentinized harzburgites and dunites, with lesser serpentinite. The ore mineralogy consists mostly of goethite, serpentine-group minerals, quartz and poorly crystallized, X- ray amorphous materials. Minor constituents are hematite, gibsite, olivine and enstatite. In the Ore Dressing plant, the mine feed is subjected initially to proper sizing and blending to produce a homogenized mix. Subsequent drying and upgrading, by selective crushing and screening of rock kagments through a Barmac circuit, complete preparation of the ore for pyrometallurgical processing. Part II.- Pyrometallurgy, Fuel and Power Generation J.H. Comgan - Manager ? Production Falconbridge Dominicana, C. por A. Bonao, Dominican Republic Falcondo's energy requirements are based on oil which is refined on site to provide distillate to carry out drying and selective reduction of the nickeliferous ore in the shaft furnaces, plus bunker oil to produce electrical power for process melting, refining and ancillary use. The dryer product at 1.68% Ni is briquetted and passed counter current to hot reducing gas in 12 vertical shaft furnaces. The hot calcine discharge is melted in two high power electric furnaces at very high secondary voltage. The crude ferronickel is ladle refined and cast as 15 kg ingots or 125 gm ferrocones.

Jan 1, 1993

As part of the Australian Mineral Industries Research Association (AMIRA) P9 project, methods of characterising both the ore and the machines in flotation circuits have matured considerably over the past 15 years. Machine characteristics include gas dispersion measurements, such as bubble size, gas hold-up and superficial gas velocity. Ores can be characterised in terms of floatability parameters on a size and mineral basis. Measurements have been performed on various copper plants in many countries around the world over the last 5 years. This paper outlines the cell and ore floatability characteristics of each copper plant and provides a discussion on the differences between these plants. In general, most porphyry copper ore bodies are processed at high tonnage through several parallel banks of cells at each stage of flotation. The floatability parameters of these copper ores are very similar in terms of rate of flotation and proportion of fast, slow and non-floating material. The cell characteristics are also similar, with superficial gas velocity, bubble sizes, and gas hold-up values being of similar magnitude. Investigation of the similarities and differences of the modem copper flotation circuits has allowed an increase in understanding of the particularities of copper flotation. Comparison against other copper circuits provides a benchmark and opportunities for future optimisation.

Jan 1, 2007

By H. Perez, A. Lavoie, V. Prévost, P. Létourneau, P. Lind

The Home smelter is a custom copper smelter located in Rouyn-Noranda, Quebec. In 2005, the smelter produced 145,000 t of copper containing 807,000 oz of gold, 20,388,000 oz of silver in addition to 515,000 t of sulphuric acid. Recently, a flexible flow sheet has been developed incorporating the intermittent use of the Noranda Continuous Converter allowing for the increasing or decreasing of production based on market conditions, while attaining 90% or greater sulphur fixation regardless of operating mode. For 2006, the smelter is operating in full production mode and production is expected to be approximately 185,000 tm of copper. Mechanical modifications, process changes, metallurgical concepts, minor element treatments, and operational techniques that have allowed the smelter to develop this flexibility are presented. Current efforts to increase the productivity of the converter aisle and anode furnaces as well as improvements being made to address fugitive emissions are also discussed.

Jan 1, 2007

By M I. Pownceby, N Karimian, A Frierdich

These may be found with goethite through mechanisms including direct substitution or coprecipitation of nanocrystalline phases. Understanding P incorporation in goethite has significant implications for Australia’s iron ore industry as it lowers their commodity value. The current study tests a novel low-temperature technique to extract P impurities from synthetic goethite phases under O2-free ambient conditions by utilising Fe(II)-catalysed recrystallisation. The objective of this study was to examine the effect of the Fe(II)-catalysed recrystallisation of goethite on the geochemical behaviour (mobility and speciation) of co-associated P. To achieve this, we tracked changes in labile P (aqueous and 1M NaOH extractable) concentrations over time in goethite suspensions which were reacted with Fe(II)aq for 14 days under circumneutral pH conditions and room temperature conditions. Temporal changes in Fe mineralogy were investigated via synchrotron-based X-ray absorption spectroscopy. Iron K-edge extended X-ray absorption fine structure (EXAFS) spectroscopy confirmed goethite as the only mineral phase in P-free treatments while goethite (~86 per cent) and feroxyhyte (~14 per cent) were the main phases in 1.0 per cent P-containing treatments after a 14- day reaction with Fe(II)aq. According to our findings, the treatment of P-goethite with Fe(II) for a duration of 7–14 days, followed by a 24-hour extraction of the reacted solids using 1M NaOH, results in the removal of approximately 79.5 per cent of the initial P content. This removal encompasses both the aqueous fraction (~4.5 per cent) and the surface adsorbed fraction (~75 per cent) from the 1 per cent P-bearing mineral phase. Notably, this approach demonstrates an improvement in P extractability, with approximately a 10 per cent increase compared to the 1 per cent P-goethite sample that was not reacted with Fe(II).

Sep 18, 2023

By J. K. A. McLEOD

Address by the President of the Institute (Mr J K A McLeod) in presenting the Institute Medal to Howard Knox Warner, C.B.E. Address by Howard Knox Warner after accepting the award.

Jan 1, 1978

By J. A. M. Cano

With a view toward increasing its product competitiveness in the foreign market, SAMARCO MINERACAO S/A has developed high MgO type pellets at its pilot plant for performing direct reduction simulation tests. Additives such as dolomitic lime and magnesite were used for increasing pellet MgO content. Comparative direct reduction simulation tests were conducted both in SAMARCO and foreign laboratories. The test results showed that it is possible to produce direct reduction type pellets with satisfactory metallurgical properties, which can be successfully processed at increased temperatures in direct reduction furnaces.

Jan 1, 1992

Bateman Engineering managed the establishment of a second diamond treatment plant at the Letseng Mine in the Mokhotlong District of northern Lesotho, about 100 km from the town of Buthe Buthe. Letseng Diamonds Proprietary Limited, is owned 70 % by Gem Diamonds and 30 % by the Government of the Kingdom of Lesotho. The second plant, which commenced construction in late 2006, doubled Letseng Mines' hard rock processing capacity from 2.6 million t/yr to 5.2 million t/yr, making it the worlds' seventh largest diamond mine by throughput. Bateman Engineering provided the engineering design, procurement and construction management of the new plant.

Jan 1, 2010