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By Edward R. Rose

This paper summarizes and emphasizes the potential importance of Canadian rare-earth occurrences, and recommends that efforts to locate and evaluate rare-earth deposits should be increased. Increasing world markets, depending on intensive applied research into the numerous unique and remarkable chemical and physical properties of the rare-earth elements (REE), are developing; their properties and uses are becoming better known; methods of separation are much improved. The REE group comprises a Cerium (Light) subgroup of 7 metals and an Yttrium (Heavy) subgroup of 9 metals. REE are trace elements in many rocks and minerals, and major constituents of more than 50 rare-earth minerals, many of which are difficult to detect and identify. They occur preferentially in acidic and alkaline igneous and metamorphic rocks, including carbonatites, as well as in placer deposits, certain uranium deposits, phosphate rocks and others. The main ores now are bastnaesite (in Precambrian carbonatite), monazite and xenotime (in Recent beach sands) as well as uraninite and brannerite (in Huronian quartz-pebble conglomerate) and loperite (perovskite) and apatite (in alkaline complexes). World resources are summarized. Twenty mines in 1973 produced an estimated world total of about 31,000 tons of contained rare-earth oxides (REO), 19,341 tons of which came from one mine at Mountain Pass, California. A selected fifteen, of 315 or more Canadian occurrences, are briefly described and compared, and their relative merits indicated. Their abundance and variety suggest the possibility of finding high-grade deposits in many geological terranes in Canada.

Jan 1, 1979

By C. W. Dunham

DESIGN of the structures for the Morenci Reduction Works involved many interesting problems. Naturally, the chief purpose of these structures is to house and support the equipment and other things necessary for or incidental to the conduct of production. hence most of the features of the design were developed to suit these particular conditions; however, several are so generally applicable as to warrant description.

Jan 1, 1942

By R. R. Sayers

The increasing use of hydrogen fluoride (annual consumption now exceeds 500,000 pounds (1)4/) directly and its occurrence as a byproduct of the utilization of fluorine compounds in the mineral industries, especially in metallurgical processes and in the refining of petroleum products, has aroused interest in its toxicity, and a brief review of the literature, with special reference to the hazard of poisoning in the mineral industries, seems to be opportune. Recently, residents in the vicinity of aluminum plants have been complaining of injury to livestock and vegetation as well as to their own health from the gases discharged into the air during operation of the plants, hydrofluoric acid gas apparently being the offender. The comparatively recent utilization of hydrofluoric acid in the alkylation process for the production of high-octane gasoline has raised the question of the hazard of poisoning in the petroleum Industry. In addition, the use of fluorine-containing refrigerants has extended the potential al exposure outside of industry (2).

Jan 1, 1945

By Ragnhild E. Aune, Shahid Akhtar, Reza Beheshti

"The potential use of Black Dross (BD) as a raw material for the production of refractories, fluxing agents and glasses is the main motivation of the present study. Heat treatment experiments were carried out in Ar, and under reduced pressure (20 Pa), to evaluate the salt removal efficiency. The chemical composition of the BD after heat treatment was investigated by SEM-EDS and XRD analyses. Based on the present results, it is established that the salt starts to evaporate at ˜1273 K in Ar, and under reduced pressure. The salt removal efficiency in a 20 g sample was found to increase in both cases as a function of time and temperature. Moreover, in Ar the chlorine concentration was lowered to 0.3 wt% after heat treatment at 1523 K for 10 hours. Under reduced pressure, however, 0.2 wt% residual chlorine was obtained after 8 hours at 1473 K.IntroductionIt is believed that aluminum recycling in the near future will become the main route of aluminum production [1]. Black dross (BD) that is produced during this process contains, among other things, high amount of salts like NaCl and KCl [2, 3]. Almost 800,000 tons of BD is annually land filled in United States and this number continues to grow with the increase in aluminum recycling [2]. The BD should be dumped in controlled land field and it is costly procedure [4, 5].The water-soluble compounds in BD react with water or environmental humidity and release chlorides into the water and/or generate toxic gases such as H2, CH4, NH3 and H2 S [6-8]. In the Europe, BD is considered as toxic waste and its disposal as landfill is forbidden [8, 9]. After salt removal, the BD is considered to be non-hazardous and can be buried under ground [10].On the other hand, BD do also contains many relatively valuable compounds that may be changed in to useful materials as a result of further treatment [11, 12]"

Jan 1, 2012

By Daniel T. Brian, O&apos

Exploration targets and results in the mining industry are commonly summarized in terms of tonnage and grade. Business appraisals require, as additional information, the expected profit or loss implied by the physical summary. The early incorporation of knowledge gained through financial analysis computations can provide a means for economically resolving many common exploration and development problems. Examples of such applications from the activities of exploration planning, reconnaissance, land acquisition, and development planning are presented in this paper.

Jan 1, 1969

By Lance Rasband, Richard Hanke, John Starcevich

"The 17.4 meter (57 ft) diameter tunnel boring machine (TBM), the world’s largest at the time of her launch in 2012, locally referred to as “Bertha,” is stuck. Incapacitated due to mechanical failure approximately 36 meters (120 ft) beneath downtown Seattle, situated precariously between the deteriorating Alaskan Way Viaduct and the failing Seattle Seawall. Accessing Bertha with a vertical shaft provides the best approach to address all facets needed for repairs and will allow the full removal of Bertha’s cutter head and related inner workings. Limited area above the tunnel alignment and the physical restrictions of existing infrastructure, create significant challenges for the design of an otherwise symmetrical shaft, requiring special attention to design and layout. Consequently, the access/recovery shaft design required a combination of 3m, 2.5m, 2.2m, 1.5m and 1m diameter unreinforced drilled secant piles coupled with various ground improvement techniques and dewatering, to fully satisfy the shoring design requirements. This paper will describe the shaft installation procedures, equipment used and pitfalls encountered while undertaking access shaft construction of this magnitude.INTRODUCTIONTunneling on Seattle’s SR99 tunnel project began in July of 2013. After slowly mining through a 4.5 m (14.76 ft) thick fiber-reinforced concrete headwall and the first of three stabilized “safe havens,” Bertha would proceed along the proposed alignment through 122 meters (400 ft) of jet grout improved soil at a rate of slightly over 1.6 m (5.25 ft) per day. Once past the improved area, it was planned that “Bertha” – would be moving at a rate of about 11 m (36 ft) per day. By the end of October 2013, Bertha had mined roughly 131 m, (430 ft) averaging 1.4 m (4.6 ft) per day and had begun mining within native soils. By December 2013, tunneling had reached the 244 m mark and Bertha was averaging 3.6 m (11.8 ft) per day, achieving as much as 12.8 m (42 ft) of progress on given days. Unfortunately, on December 6th, 2013, Bertha began to stumble and all progress quickly came to a halt.It was initially reported that an obstruction had stopped Bertha in her tracks. The preliminary investigation involved installation of 10 deep dewatering wells to reduce the hydrostatic pressure around the TBM, and allow visual inspection of the cutter head from within the TBM, and also to investigate for the presence of obstructions at the face of the cutter head. During this inspection, fragments of steel pipe were discovered entangled in the cutter head. The fragments were apparently from an abandoned 254 mm (10 in.) diameter monitoring well casing, previously installed by WSDOT to monitor ground water conditions for the design and planning of this tunnel project. After the steel was removed from the cutter head and cleared from Bertha’s path, tunneling resumed. It was then discovered that Bertha was only able to generate a slow crawl."

Jan 1, 2016

By R. Ranjan

Stanstead granite has been investigated with respect to its dynamic compressive strength and its strain-rate dependency. A standard Split-Hopkinson Pressure Bar (SHPB) apparatus has been employed to generate strain rates of up to ~500/s through high-velocity impact. The diameters of the test samples were 19 mm, and tested under impact velocities up to ~20m/s. It is found that even within this limited range of strain rates, the dynamic compressive strength for the granite showed nearly a 100% increase in value compared to those obtained under static loading conditions (e.g. compressive strength of 394 MPa at a strain-rate of 600/s, compared to 215 MPa obtained under static loading). The details of the test are described in terms of incident, reflected and transmitted stress pulses, along with means to achieve stress equilibrium in the test samples under dynamic loading conditions. The advantage and drawback of the use of ‘pulse shaping’ techniques to achieve dynamic stress equilibrium are also detailed.

Jan 1, 2010

By Marcus Nadler

WAGES in the United States, in spite of the wage freeze, have increased materially. Overtime payments have become standard practice in almost all industries. Now efforts are being made to place wages on an annual basis, and if this is adopted, it will result in an increase in the cost of production. Organized labor today is more powerful than ever before; union membership is large and steadily increasing, and in many instances membership in the union is a prerequisite to employment. The treasuries of many unions are strong as a result of the large membership and full employment. The unions, therefore, today are in a much better position than ever before to carry on long strikes. Politically, too, the unions are more powerful today than they ever were. On the basis of their strength, one may expect that some of the demands that the labor unions will make in the not distant future will be granted. It is, therefore, quite evident that before long, particularly when the curtailment in war production reaches about 40 per cent, this country will be confronted with a serious labor problem.

Jan 1, 1945

By E. B. Freidina

We have investigated a new electrochemical process for preparing lead-calcium alloys. Calcium metal, reduced fiom a molten chloride mixture, forms an alloy with liquid lead cathode. The addition of calcium carbonate to conventional CaC12-NaCl electrolyte enables us to avoid chlorine production on the anode and replace it with oxygen and carbon dioxide. The ternary system CaClz-NaC1-CaCO3 has a range of melt compositions, where the electrolysis can be held below 650°C. In order to prevent the side reaction of carbon deposition on the cathode we have separated the anolyte from the catholyte with alumina diaphragm. The factors, which affect the level of impurities and the current efficiency of the process, are discussed.

Jan 1, 1999

By Joseph Grumer

Reported fiscal year 1973 studies of fires and explosions seek to develop capabilities during mining operations to detect and quench ignitions of gas in the face area, to detect and quench by means of passive or triggered barriers explosions propagating in rock-dusted coal dust, and to detect incipient fires early enough for easy extinguishment. Research discussed includes minimum air velocities to lift coal or rock dusts, surveys to determine adequacy of rock dusting, chemical agents to quench gas or coal dust explosions and their relative efficacies, spectra radiated by explosions, and nozzle sprays of extinguishants.

Jan 1, 1973

From 1886, the first year shipments were recorded, until 1939, the Leadville district produced over 3,500,000 long tons of manganiferous ore. Of this total, metallurgical-type ores comprised 27 percent and manganiferous iron ores suitable for fluxing in lead smelters made up 73 percent. In 1939, the Bureau of Mines, as part of the strategic minerals investigative program being conducted at the time, requested the Mineral Industries Survey Section of the Mining Division to make a comprehensive study of the manganese resources of the Leadville area. This investigation, owing to the caved and flooded condition of the underground mine workings, was necessarily confined to a study of old maps, production records, and geological reports, and the results were published as an Information Circular in July 1940.

Jan 1, 1949

By AIME AIME

A REQUEST for information as to the details of activities of the Engineering Council was made by the Joint Conference Committee for the benefit of the new American Engineering Council. , This request was complied with, and the scheduled reply so succinctly sets forth the activities of the old Council as well as the scope of possible activities of ,the new Council, about whose efforts there has been much discussion, .that it' is given herewith in full, except the 'budget which is summarized.

Jan 1, 1920

By J Sargeant, T Levi, J Theiler, B Beamish

Two coal samples (810 Panel and Area 900) collected from Clarence Colliery have been tested under a controlled heating procedure to evaluate the gas evolution trends corresponding to increasing temperature. Gas evolution data are normally used to identify key gas indicators and validate the trigger action response plan settings for the mine as part of the Principal Hazard Management Plan for Spontaneous Combustion. The samples were located some 6 km apart and there is a significant coal-type difference between them. At low temperatures (<100°C), the Graham’s ratio (GR) values for the two samples are almost identical. However, at elevated temperatures, there is a significant difference, with the 810 Panel coal having higher GR values than the Area 900 coal. This is most likely due to a difference in the coal reactivity. The 810 Panel coal does not evolve ethylene until temperatures in excess of 140°C are reached, whereas Area 900 coal evolves ethylene once temperatures in excess of 120°C are reached. The 810 Panel coal also produces significant ethane evolution (200 ppm) at low temperatures (50°C) due to the presence of retained ethane seam gas, which decreases as the temperature increases due to desorption from the coal. Once the coal temperature exceeds 130°C, the ethane evolution increases again due to coal oxidation reactions, reaching levels of 50 ppm. In contrast, the Area 900 coal has no significant low-temperature ethane evolution, and ethane evolution only increases once the coal temperature exceeds 120°C. There are also noticeable differences in the trends of other gases evolved from the coal. These findings have implications for the interpretation of gas monitoring results from the two different areas of the mine. They also illustrate the need for obtaining results from each new area of a mine as it develops so that changing gas evolution trends can be identified in advance of mining.CITATION:Beamish, B, Sargeant, J, Levi, T and Theiler, J, 2015. Gas evolution trends for coal from two different areas at Clarence Colliery, in Proceedings The Australian Mine Ventilation Conference, pp 273–278 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 31, 2015

By Inoka E. Perera, Robert Hildebrandt, Gerrit V. R. Goodman, Krzysztof Cybulski, Zdzisław Dyduch, Michael J. Sapko, Marcia L. Harris

To prevent coal dust explosion propagations, rock dust needs to be lifted and suspended in the air with the coal dust during an explosion. The addition of anti-caking agents prevents caking of rock dust in the presence of water. Mining and rock dusting processes can frequently create alternating layers of rock dust and float coal dust on mine surfaces. For this test series, a thin layer of coal dust was distributed on top of a layer of either treated or non-treated rock dust in the Experimental Mine Barbara, Poland. The experimental results compare the effectiveness of treated and non-treated rock dusts to attenuate a propagating coal dust explosion initiated with either strong or weak methane explosions. Experimental results indicate that the treated rock dust performs better than non-treated rock dust in arresting a propagating explosion, especially in the presence of moisture.

Jan 20, 2020

By M. O. Serbousek

The load-transfer mechanics of fully grouted roof bolts in coal mines have been investigated in laboratory and analytical studies. The purpose of this Bureau of Mines research is to increase understanding and better interpret data from routine field pull tests and to develop a numerical model of a grouted bolt that can be used in a global computer model of a mine roof. Analytical studies using closed-form solutions and finite-element techniques were compared to experimental results. Laboratory work includes variation of bolt length, hole diameter, and grouL type. Pull tests were pel'fol·med on 4-, 2-, and I-ft bolts in holes of 1-and I-3IB-in diameters. Both polyester resin and inorganic grouts were used as the anchorage medium. Strain gauges were installed on the bolts at several locations to observe the rate of load transfer from the bolt through the grout to the rock mass when a force was applied at the bolt end using standard jack pull testing procedures and equipment. The average anchorage length of 4-and 2-ft bolts was 22 in. Grout type and hole size variations did not produce a significant effect on the rate of load transfer from the bolt to the rock.

Jan 1, 1987

By C. Ramasamy

The tariff reductions on imports, as a part of on-going liberalisation process in India, has fueled competition within and outside India and has, in turn provided an opportunity to reach global markets. This change calls for quality upgrades and cost-competitiveness without impairing the environment. In this context, gas based processes, contributing to improvement in quality and environment as well as processes where controls are applied when gases inimical to environment are involved, are discussed in a remelt/cast-house scenario. The impact of such processes on fabrication cost of sheet ingot is seen alongwith consumption and cost of materials and compared with a world class standard plant in North America.

Jan 1, 1996

By M. Panayotova

Most of the quantity of the water soluble xanthates, used in mineral flotation, is consumed in the process. However, the residue amounts are water contaminants downstream the mineral processing operations and can be toxic to aquatic biota at concentrations of 1 mg/L. In order to be able to discharge water from tailing ponds to natural water bodies the concentration of xanthates has to be decreased. The present paper studies the uptake of potassium ethyl xanthate by directly modified with copper and lead ions natural zeolitic rock, without passing through zeolite transformation into homoionic form. Modified zeolite exhibits high, comparable with powdered activated carbon of chemical purity grade, capacity to remove potassium ethyl xanthate from model wastewater, with pH in the range of 7?9 and pollutant concentration in the range of 10-150 mg/L. The pollutant immobilization is fast. Both Cu and Pb modified zeolite behave as selective with respect to xanthate in the model wastewater, and Cu-modified zeolite possesses higher selectivity. The equilibrium is best described by the Freundlich equation. Keywords: xanthate, wastewater, modified zeolite

Sep 1, 2012

By M Gasparon, J Harris, T Baumgartl, D J. Williams, M Edraki, P A. Kirsch, D Rowe

RISKGATE, an Australian Coal Association Research Program-funded (ACARP) initiative, has been designed to assist the Australian coal mining industry in improving minimum standards for safety performance, efficiency, operating practice and training. The online system is innovative in that it is built upon a foundation of industry expert knowledge gathered through action research workshops, which is further supported by a broad array of industry, academic and technical resources. In operation, RISKGATE offers a continuum for knowledge transfer and communication of current practice in risk identification, assessment and management in the coal mining industry. The primary mission of RISKGATE is to focus industry attention on prioritising control management as a way to achieve acceptable risk.A Coal Mine Tailings Dam Module has recently been added to the RISKGATE suite. The key risk, or initiating event, associated with coalmine tailings dams is catastrophic failure of the dam, leading to the release of tailings and water. This can occur due to geotechnical instability of the dam itself or of its foundation, overtopping and erosion of the dam, and piping failure of the dam itself or of its foundation. Coalmine tailings dams are also prone to seepage into the foundation and through the dam, particularly during operation when large volumes of water are discharged with the tailings. The most significant risk associated with seepage is the release of potentially contaminated water to the environment. Contamination can take the form of elevated salinity, acidity and dissolved metals. Run-off from coalmine tailings can cause erosion and can also potentially contain contaminants. Desiccation of the tailings surface can result in dust generation and dispersion.The paper presents the background and context of the RISKGATE project, the need for the addition of the RISKGATE Coal Mine Tailings Dam Module, and a description of the developed module, including the five initiating events considered, their causes and associated preventive controls, and their consequences and associated mitigating controls. This paper concludes with a discussion of the ways in which Australia’s coal mining companies are starting to apply the RISKGATE body of knowledge at their sites, which will flow onto the management of their tailings dams.CITATION:Williams, D J, Kirsch, P A, Gasparon, M, Baumgartl, T, Edraki, M, Rowe, D and Harris, J, ?2014. Application of RISKGATE to coal mine tailings dams, in Proceedings Life-of-Mine 2014 , pp 219–230 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 16, 2014

By Marco Antonio Meggiolaro

Notches are preferential sites for fatigue and for environmentally assisted cracking (EAC) initiation. Semi-empirical notch sensitivity factors have been used for a long time to quantify notch effects on fatigue design. Recently, this concept has been mechanically modeled using techniques which properly consider the notch tip stress gradient influence on the fatigue behavior of mechanically short cracks. This model properly calculates such values from the basic fatigue resistances of the material, its fatigue limit and crack growth threshold, considering the characteristics of the notch geometry and of the loading, without the need for any adjustable parameter. Such criteria to estimate notch sensitivity and tolerable short cracks on fatigue have been extended to EAC conditions and verified by proper tests. In its simplest version, the criterion for the maximum tolerable stress under EAC conditions uses the resistances to crack initiation and to large crack propagation and the characteristic short crack size under EAC, considering the crack size and stress intensity factor. Moreover, the tolerance to short cracks under fatigue and under EAC conditions can be unified in an extended Kitagawa-Takahashi diagram, a new and potentially very useful tool for material selection tasks.

Aug 8, 2018

By G. L. Humphrey

Although silicon carbide has been an important manufacture refractory for many years, knowledge of its thermodynamic values has been seriously lacking. In fact, some of the very properties that make it a useful substance, particularly chemical inertness, obstruct determination of its heats of formation and reaction. This paper reports the results of new measurements of the heats of combustion and formation, low-temperature heat capacity, entropy at 298.16°K., and heat-content and entropy increments between 298° and l,800°K. Two varieties of silicon carbide were studied -the common, hexagonal (type II) and cubic. The data are combined to obtain heat and free-energy-of-formation functions, which are given in tabular form. It is shown that the cubic variety is the more stable at temperatures to at least 1,800°K but, because of the inherent difficulties and errors in the heat-of-formation determinations at 298°K, it was not found possible to specify the free-energy difference accurately. The mechanism of silicon carbide formation from silica and carbon is not known and is not ascertainable from thermodynamic data. It appears improbable, however, that it can be a single-step reaction. Some reactions involving silicon monoxide gas and metallic Silicon, as possible intermediates in silicon carbide formation, are considered and shown to be thermodynamically feasible.

Jan 1, 1952