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By Max W. Ball

Our ever-increasing use of minerals has been the outstanding fact in our American economic development. The rise in our standard of living in the past century is without equal in human history. Nowhere in time or place has the man who works lived so well, or the man who cannot work been so well cared for. We live in a new world, even the poorest of us, that our forebears of 1849 could not have dreamed. That new world has come mainly from our use of minerals. Our per capita use of nonmineral products has grown too, but by only a modest amount. Food consumption per person has grown about 15 per cent in the past fifty years; lumber use per person ,has fallen 56 per cent and that of wood for fuel 65 per cent. Of all the products of field and forest, our use, per capita, may have increased by one fifth during the present century. In contrast, our per capita use of minerals has multiplied several times. Each of us uses 2% times as much steel and 16% times as much petroleum as our fathers used in 1900. In less than half a century our per capita consumption of all minerals has probably risen by 200 to 250 'per cent. Man once built with wood; today he builds mainly with brick and stone and steel. Once he traveled by the power of hay and oats; today he travels by the power of coal and oil. Rubber made from minerals is already better for some uses than rubber tapped from trees; before long it will be better for most and perhaps all uses. Even our ladies' graceful legs are clad in mineral fiber, where once animal or vegetable fiber would have covered them. Our high standard of living is a product of the machine.. The machine is made of minerals. The machine is driven by minerals. The machine age is a mineral age.

Jan 1, 1949

By T. Fabritius, L. Hekkala, J. Härkki

The Outokumpu steel belt sintering technology is used for manufacturing chromite pellets that are charged into smelting furnace for ferrochromium production. Hot air is blown through the moving bed of raw pellets. Direct temperature and flow measurements are difficult to do in the bed of a real scale belt sintering process. Therefore, a tested and reliable mathematical model would be a valuable help for optimising operational parameters of the process and designing new constructional improvements. The aim of this work is to present a mathematical model that calculates the gas flow and temperature distribution in the bed of pellets and the atmosphere. Computational fluid dynamics program FLUENT is used to calculate the gas flow, composition and temperature of the gas in the sintering bed during processing. Energy equation for the bed, containing the effects of evaporation of water and oxidation of carbon and iron oxide, will be added to the model to obtain the temperature of the pellets. The porous media model used for pressure drop calculations in the bed is shortly discussed. A comparison between CFD-calculations and experiments with a pilot scale batch-sintering reactor are also presented. The final model can be used as an engineering tool when developing the process and the equipment further. Different designs can be easily tested with the model and the effects of the changes to the flow pattern and temperature distribution can be studied.

Jan 1, 2004

By H. E. Peterson, W. L. Anderson

"INTRODUCTION The great demand for tungsten incident to the war has led to the exploration of a large number of low-grade tungsten deposits. To properly evaluate the low-grade deposits it is essential to have available a dependable method of analysis applicable to all types of low-grade tungsten ores. Results reported on the tungsten content of the ores have often varied quite widely and have led to confusion. The Bureau of Mines has been requested by Government lending agencies and by companies interested in the production of tungsten to publish a general method for the determination of tungsten in low-grade ores. To meet this need, the Bureau of Mines is herein submitting two methods for analysis that have been proved on a large number of tungsten-bearing ores various types in the Bureau of Mines laboratory in Salt Lake City. Also, a third method was developed that requires no cinchonine and has proved to be applicable on most tungsten ores. The cinchonine method is the generally accepted for analysis of tungsten ores. Very reliable results can be obtained by this method if certain precautions are taken, as outlined in this report."

May 1, 1943

By Bernard H. Hertlein

The introduction of LRFD methods for structural design has been a gradual process by AASHTO, ACI, AISC, ASCE, and the FHWA, which has largely been ignored by the deep foundations industry. In 2007, however, the industry has been obliged to embrace LRFD for any deep foundations on projects involving federal funds. The authors are concerned that the risks caused by the need for, and the difficulty of providing, reliable quality assurance, will result in unnecessarily high safety factors that will defeat part of the purpose of LRFD. A primary attraction of LRFD for owners and engineers alike is that it promises more efficient design, and therefore cost reductions. Unfortunately, a key element of LRFD philosophy is often overlooked - that the applied safety factors can be rationally reduced, often allowing less material to be used, thus saving costs, but only if all the risk factors involved are identified and closely controlled. This means that both the quality of the materials and the quality of the construction work must be adequately monitored, and held to an acceptable standard. In the case of deep foundations, the soil in which the foundation is constructed is also a critical component that must be taken into account in the assessment of risk factors.

Jan 1, 2007

By S. Hardcastle

Tele-remote operation of production equipment from surface will change the design criteria for underground mines. And for ventilation, with machine operators on surface, conventional planning to dilute and remove pollutants can become redundant. Natural Resources Canada with industrial partners are investigating what will be the new environmental design criteria. Additional complications include new mining equipment being designed without standard services and mines’ desire to eliminate conventional auxiliary ventilation. Findings to date show the cooling of equipment’s hydraulic systems to be the most demanding element, especially in dead-ends and when stationary. Consequently, revised ventilation based heat control strategies for equipment are being developed for the automated mine of the future.

Jan 1, 2001

By John E. Trombly

System objectives and design criteria for an in-mine visual personnel paging system are discussed. Display technologies are evaluated and tradeoffs leading to display selection are described. The prototype dispatcher's console, battery/receiver box and visual display assemblies are functionally described. The report includes circuit descriptions, schematics, parts lists and equipment cabinet drawings for the three assemblies. The report concludes with an estimate of the manufacturing cost for each assembly.

Jan 1, 1975

By A Fern, A Hawkes, o, W Smith, K Mee

Serious Injury and Fatality (SIF) prevention remains a priority focus within high-risk industries sector. A major mining operation sought to strengthen their approach to the management of high-risk activities through an in-depth review of all historical incidents that had serious injury or fatality potential (SIFp) events (sometimes known as hi-potential events). The analysis found that the organisation invested a disproportionate level of resources, time and effort on low consequence incidents with a high proportion of SIFp incidents going under the radar. It was found that 76 per cent of SIFp incidents were rated in moderate or lower risk categories and conversely, almost half of those incidents with a ‘serious risk’ rating had little or no potential for a serious outcome. As a result of this project, the operation engaged in a renewed focus on critical risk management and enhanced its operating cadence in critical risk for the workforce. This included bow tie analysis, an update to critical risk standards and increased workforce engagement in the use of critical control verifications in the field. Data analytics with lead and lag indicators continue to provide senior leadership team and risk owners with an understanding of exposure for SIFp and control effectiveness. The audience will take away learnings from a real-world case study that provides data-driven insights of the human, local and organisational factors contributing to incidents with SIF potential. In addition, participants will understand the steps taken to categorise and analyse this incident data and the initiatives currently being implemented by the organisation as a result.

Apr 16, 2024

By R. J. Kuczynski

The U.S. Bureau of Mines Reno Research Center operated a batch pilot plant to demonstrate high-temperature cyanide leaching for recovering platinum group metals (PGM) from automobile catalysts. Approximately 1,600 kg of used pellet, monolith, and metal support catalyst containing 1,680 g (54 tr oz) of PGM were processed. Forty-five-kilogram batches of used catalyst were leached with sodium cyanide solution at 160° C for 1 h under basic conditions in a countercurrent processing sequence to dissolve the PGM. Extractions from the used pellet catalyst ranged from 94 to 95 pct for Pd, 95 to 97 pct for Pt, and 64 to 81 pct for Rh. Extractions from the used monolith catalyst ranged from 7B to BB pct for Pd, 75 to 90 pct for Pt, and 43 to 71 pct for Rh. Heating the pregnant leach solutions to 275' C for 4 h destroyed the PGM-cyanide complexes, resulting in over 99.7 pct of the PGM precipitating from solution. The PGM precipitate was predominantly a powder metallic concentrate, typically analyzing greater than 50 pct PGM. Heating destroyed cyanide to less than 0.2 mg/L. Both the pellet and monolith residues were evaluated for disposal using the EPA Toxicity Characteristic Leaching Procedure.

Jan 1, 1995

By J. Hanna

Four Ca-bentonitic clays from Alabama were evaluated for use in Diammonium Phosphate (DAP) or Urea Ammonium Nitrate (UAN) fertilizer suspensions. The viscosity and gel strength of suspensions prepared with different proportions of a Western bentonite clay and sodium exchanged Alabama clays, were measured as a function of clay content and dispersant concentration. The results obtained suggested that three of the Alabama Ca-bentonites would replace about 40% of the more expensive Western bentonite in UAN and DAP fertilizer suspensions. The performance of the Na-modified clays, prepared according to the TVA soda ash method, was as good or even better than those observed for the Mg-, Na/Mg-or K-modified clays. The TVA clay modification procedure appears to be reliable and cost effective.

Jan 1, 1989

By Yunsheng Yao, P. Golledge, A. D. S. Gillies

In order to investigate the explosibility of sulphide mineral dusts, sulphide ore samples were collected from five underground metalliferous mines in Australia. The mineralogical and chemical composition of the dust samples was analysed by X-Ray Powder Diffraction and Atomic Absorption techniques. Simulated post detonation fumes were produced and used in dust explosibility tests to examine the influence of the fumes on sulphide dust ex- plosions. These tests were conducted in a 20 Litre Siwek Explosion Chamber with measurement and control system that is regarded as a standard testing system worldwide for dust explosion studies. The dust mineralogical composition and dust explosibility tests indicated that the content of sulphur can not accurately predict the explosibity of the sulphide dust. The percentage content of pyrite in the sulphide dust can be a relatively reliable diagnostic criterion in evaluating the risk of sulphide dust explosions in the mining of a massive sulphide orebody. The hybrid explosion tests demonstrated that the post detonation fumes from ANFO not only decrease the lower explosion limit of the sulphide dusts, but also increase the severity of the dust explosions. The explosion pressure reaches its peak value when the fumes content in the explosion chamber is about 20 per cent by volume

Jan 1, 1997

By P. C. Thakur

Methane has been a hazard since the beginning of coal mining and has influenced, more or less, every aspect of coal mine design. It is receiving increased attention lately because the rate of methane emission in coal mines is increasing as increasing demand for coal leads to exploitation of deeper seams and the use of higher productivity equipment. Consequently, the government and private industries have directed a great deal of effort towards understanding and solving the problem of methane emission in coal mines. In the United States, Consolidation Coal Company has pioneered research in this area since the early 1950's.1 Currently this work is being expanded by Consol through the Mining Research Division of the parent company, Continental Oil (Conoca), to find new techniques for degasification of virgin areas as well as control of methane in gob areas. Basic reservoir properties of coal seams, such as gas content, reservoir pres-sure, diffusivity, porosity and permeability are better understood today largely through the efforts of the U. S. Bureau of Minese2,3,4 It is possible now to identify and model the basic mechanism of gas emission from coal and to forecast steady as well as unsteady state emission of methane in coal mines with some degree of reliability. Combining this knowledge with any ventilation simulator should often identify problem areas in advance and permit adequate methane control measures to be planned.5 Another recent innovation in methane control is the horizontal hole drilling technology. The U. S. Bureau of 1-1ines and the Mining Research Division of Conoco have independently developed techniques for drilling horizontal holes 300 to 600 m deep6 The Bureau's method employs a rotary drill string while Conoco uses a non-rotating string with a down hole drill motor. It is the authors' view that the latter provides more positive control on bore hole deviation both vertically and laterally and appears to be faster, though somewhat more difficult to operate. The rate of methane emission depends on a number of factors which can be broadly classified in two groups. These are (1) the basic reservoir properties of

Jan 1, 1977

By Rob Boom, Yasuyuki Tozaki, Frank M. Wheeler

Selection of a suitable site for a metallurgical plant is crucial for the success of the business case. For a brownfield project, with the decision to locate the project on a site with existing production facilities and activities, the selection of the site has been made. For a greenfield project, important economic and logistical considerations include proximity to primary and secondary resources and/or to the market, infrastructure, and access to energy and water. National and regional aspects, including the social license to operate, can be decisive in final site selection. Key to recruiting and retaining a labour force are proximity to urban areas, along with weather and health conditions at the site. Risk factors include site geotechnical parameters and topography, contamination, as well as probability and types of potential natural disasters.

Jan 1, 2015

By C. J. R. Braithwaite, Giancarlo Rizzi

"The Navan zinc-lead ore deposit (70 million tonnes) is hosted principally (97%) by the Meath Formation (Lower Carboniferous, Courceyan, Navan Group), comprising a lower, mainly carbonate mudstone unit, the Stackallan Member, and an upper grainstone-dominated unit. TheStackallan Member, about 60 m thick, comprises about 35 peritidal cycles including an oolitic grain-stone interval. Grainstones forming the upper part of the formation, about 150 m thick, comprise at least six shallowing-upward ramp cycles. Emergence horizons are indicated by subaerial dissolution surfaces, in situ breccias, and a single palaeosol.Most dolomitization at Navan is con?ned to the Meath Formation. The linear dolomite body,trending NE-SW, has a ?attened, laterally limited, tabular geometry in cross-section, suggesting that dolomitizing ?uids initially rose vertically, cross-cutting stratigraphic and sedimentological bound-aries, although ?uid ?ow was subsequently controlled by these features.Three stages of dolomitization are indicated by textural relationships, cathodoluminescence (CL),oxygen isotopes, and ?uid inclusion data. Stage 1 crystals, with generally dully luminescing cores and up to six overlying subsidiary zones, are the main replacive phase. Crystal surfaces are commonly corroded and overlain by bright stage 2 rhombs (which also form new nuclei lining molds and fractures). Three subsets of zones are present in stage 2 crystals: bright, non-luminescent, and dull; these are locally separated by additional corrosion surfaces. Stage 3 comprises relatively large baroque crystals, generally dully luminescent but with up to seven sub-zones. Isotopic and ?uid inclusion data suggest growth of successive stages from waters which became progressively hotter(60°–160°C).The distribution of the ores follows the dolomite trend. Ores were precipitated between Stages1 and 2 of dolomite growth, following Stage 2, and also during the nucleation and growth of Stage3 crystals. Dolomitization and mineralization appear to have been temporally and genetically related. The cyclic sedimentation of the host rocks, which accentuates lithological and petrographical contrasts between depositional units, controlled dolomitization. The relationship between dolomitization and mineralization, which is closely associated with faults, provides powerful exploration criteria. The recognition of these features in limestones elsewhere in the Irish ore ?eld may point toward unrecognized zinc-lead prospects."

Jan 1, 1997

By C. J. R. Braithwaite, Giancarlo Rizzi

"Abstract-The Navan zinc-lead ore deposit (70 million tonnes) is hosted principally (97%) by the Meath Formation (Lower Carboniferous, Courceyan, Navan Group), comprising a lower, mainly carbonate mudstone unit, the Stackallan Member, and an upper grainstone-dominated unit. The Stackallan Member, about 60 m thick, comprises about 35 peritidal cycles including an oolitic grainstone interval. Grainstones forming the upper part of the formation, about 150 m thick, comprise at least six shallowing-upward ramp cycles. Emergence horizons are indicated by subaerial dissolution surfaces, in situ breccias, and a single palaeosol.Most dolomitization at Navan is confined to the Meath Formation. The linear dolomite body, trending NE-SW, has a flattened, laterally limited, tabular geometry in cross-section, suggesting that dolomitizing fluids initially rose vertically, cross-cutting stratigraphic and sedimentological boundaries, although fluid flow was subsequently controlled by these features. Three stages of dolomitization are indicated by textural relationships, cathodoluminescence (CL), oxygen isotopes, and fluid inclusion data. Stage 1 crystals, with generally dully luminescing cores and up to six overlying subsidiary zones, are the main replacive phase. Crystal surfaces are commonly corroded and overlain by bright stage 2 rhombs (which also form new nuclei lining molds and fractures). Three subsets of zones are present in stage 2 crystals: bright, non-luminescent, and dull; these are locally separated by additional corrosion surfaces. Stage 3 comprises relatively large baroque crystals, generally dully luminescent but with up to seven sub-zones. Isotopic and fluid inclusion data suggest growth of successive stages from waters which became progressively hotter (60°-160°C).The distribution of the ores follows the dolomite trend. Ores were precipitated between Stages 1 and 2 of dolomite growth, following Stage 2, and also during the nucleation and growth of Stage 3 crystals. Dolomitization and mineralization appear to have been temporally and genetically related. The cyclic sedimentation of the host rocks, which accentuates lithological and petrographical contrasts between depositional units, controlled dolomitization. The relationship between dolomitization and mineralization, which is closely associated with faults, provides powerful exploration criteria. The recognition of these features in limestones elsewhere in the Irish ore field may point toward unrecognized zinc-lead prospects."

Jan 1, 1997

By TUIJA MONONEN, LUDGER BENIGHAUS, CHRISTINA BENIGHAUS, Virginia del Rio, SARI KAUPPI, JUHA M. KOTILAINEN, JAVIER GÓMEZ, JARI LYYTIMÄKI

The understanding of public debates over mineral exploration and mining largely originates from exceptional situations such as mining accidents of conflicts. Less is known about how mining is portrayed and understood under more conventional settings. What storylines dominate the local day-to-day public debate? This article presents results from a comparative case study focusing on newspaper coverage of mineral exploration and mining in three European countries representing different geological and socio-economic contexts. Newspaper articles from the Geyer-Erzgebirge region in Germany, the Andalusia region in Spain, and Northern Finland are studied. The sample looks into the period between September 2018 and February 2020 and shows that regional newspapers report about mining issues relatively intensively even in the absence of major accidents or other media events causing peaks of attention. The tone of the articles is generally neutral to positive towards mining activities, reflecting the specific local settings, historical experiences, and future expectations. Despite the different contexts of the three countries, there were considerable similarities to the topics highlighted, including common themes of mining revival, mining events and social interaction, history of mining, and damages related to mining. Past, present, and future employment opportunities related directly or indirectly to the mining sector are key storylines. Another recurrent underlying theme is the need to balance environment and safety risks and socio-economic prosperity, typically covered through ordinary disputes among the mining sector, public authorities, regional non-governmental organizations, and local initiatives.

Jul 6, 2021

By G. D. Nicholls

There have been very few attempts to isolate the various factors that contribute to the overall imprecision of geochemical analytical procedures, due in part to the difficulty of distinguishing between them. The technique of spark source mass spectrography permits a ready distinction between the contributions to overall precision from sampling error and instrumental and other errors. With conventional methods of sample preparation for this technique sampling difficulties are responsible for 80-90 per cent of the overall imprecision. Examination of the probable location of the major difficulties in sample preparation indicates that the preliminary stage of grinding, mixing and extraction of a first aliquot (about 1/100 of the original sample) is generally perfectly adequate. The difficulty lies in the subsequent stages of sample preparation. Dry mixing techniques are unlikely to give good precision if the sub-samples actually examined by the analytical technique are less than 10 mg in amount. Solution techniques are less prone to sampling difficulty. Fusion techniques, unless conducted with great care, can produce more difficulty than dry mixing. Sample preparation is critical to the success of many analytical procedures. Selection of appropriate sample preparation techniques requires just as much care as the selection of techniques for the actual analysis.

Dec 1, 1971

On the preceding pages, operations of the four major producers of nickel today have been described. There are, however, other operations in the world that, while not as large, are still of importance to the over-all picture of the industry. Among these are the Finnish producer, Outokumpu Oy, a state-controlled company that operates the Kotlahti mine 200 miles northeast of Helsinki. The ore from this operation, which began production in 1959, is pentlandite, chalcopyrite and pyrrhotite, occurring as disseminations in the host rock and in breccias. The flowsheet of the 1500-tpd mill at Kotlahti follows standard practices of crushing, grinding, and flotation to produce a pentlandite-pyrrhotite concentrate and a copper concentrate, both of which are shipped to the smelter at Harjavalta.

Jan 10, 1968

By John S. Wakeman

The progress results of a pilot plant study on the effects of ball top size and other mill operating parameters are reported. Test series on taconite and quartzite crude ores using a 1.7m diameter primary mill in closed circuit with a vibrating screen indicate clear trends on the improvements of mill throughput and power consumption when using larger diameter balls. Possible effects on mill liner and ball consumption as well as future research plans are discussed.

Jan 1, 1984

By M A. Wells

The various mechanisms by which phosphorus (P) occurs and is distributed within banded iron formations (BIF)-derived iron ore are examined. In unenriched, precursor BIF P occurs predominantly as discrete grains of primary apatite. In high-grade ores hosted mainly by the Brockman Iron Formation, P occurs in three main forms:1. as secondary apatite;2. other submicron, P-rich phases (eg Rare earth containing minerals (REE), vivianite, strengite,wavellite) present in pore networks; and3. as P occurring with iron oxides, in particular, goethite.However, the presence of secondary P-bearing phases does not contribute signifi cantly to the total P level in iron ore, and it is P associated mainly with goethite, which represents the most common occurrence of P in these ores.No direct evidence for the replacement of Fe by P within the structure of synthetic goethite has been demonstrated. Therefore, it is most likely that in iron ores P associates with goethite in occluded form as adsorbed PO4 3- species or as discrete P-bearing minerals, such as strengite, wavellite or vivianite, in ultra-fine, micro-pores or within intra-domain regions of multi-domainic goethite. Such occluded P is not easily extracted with commonly used lixiviants, such as weakly alkaline leachates. Recent development of a low temperature-alkalie/water leach extraction method has been successful in reducing not only the P content, but also amounts of Si and Al inthe initial ore. Refi nement of such a method to commercial application will have enormous benefit in realising the economic potential of large tonnages of high-P (ie >0.07 wt per cent P) bearing iron ore.

Jul 11, 2011

By Bernd Friedrich, Elif Emil‑Kaya, Merve Papakci

In the production of SmCo permanent magnets with excellent temperature stability, corrosion resistance, and oxidation resistance, samarium (Sm), one of the rare earth elements (REEs), and cobalt (Co) are employed. Cobalt (Co) is a crucial component in tool materials, nickel-based alloys, tablet and smartphone batteries, and electric car batteries. REEs and Co have been listed as critical raw materials by the European Union Commission for many years. Due to the ever-growing demand for Co and REEs in technological applications, the recovery of these elements from secondary sources has garnered significant interest. There are two types of SmCo magnets, one of which contains a high amount of iron, approximately 15.2%. This paper focuses on the recycling of Fe-bearing SmCo. In this study, an oxidative leaching process with nitric acid was developed to eliminate iron through in situ hydrolysis and to dissolve REEs and Co. The influence of experimental conditions on the formation of an amorphous iron compound through the hydrolysis of Fe3+ in a nitric acid environment was thoroughly examined based on a Taguchi orthogonal array. The optimal parameters for oxidative leaching were determined to be an acid concentration of 3 mol/L, a solid-to-liquid ratio of 1/10, and a process temperature of 60 °C.

Feb 15, 2024