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By S. M. Pickering, L. T. Gregg

Appraisal of industrial minerals beneath privately owned land requires a different approach and mindset from valuation of base and precious metals or energy minerals, and from valuation of government-owned mineral lands. First, is it the value of inground minerals or of mining rights that is being sought? Second, value to whom, the mining company, a potential investor, the mineral landowner, a lending institution, the property tax assessor, or a condemnor? Third, how should mineral value be apportioned between the land and mineral owner, and a mining company with limited years of lease-hold interest? These and many other questions must be addressed before a valuation method and Discount Rate are selected. For various reasons the Income Method is most often used, with Net Present Value calculations made for long term predicted mining income. Choice of an appropriate Discount Rate is critical.

Jan 1, 2000

By B. J. Schat, A. W. O. Bots, O. S. Langhorst

Amsterdam City Council is building a new metro line, the North–South Line. The line passes under Amsterdam Central Station (a listed building) about 18m below street level. The retaining wall that has to be built underneath the existing building is an innovative construction consisting of two rows of steel piles interspersed with a solid mass of overlapping jet grout columns: a composite ‘sandwich’ wall. This paper gives an overview of the approach taken to designing (computational models) and building the retaining wall. Special attention is paid to the observational method used for the construction of the jet grout columns.

Jan 1, 2007

By M. Shamsuddin

Information on total estimated uranium reserves and domestic requirements have been collected, A survey has been made on the possibilities of recovery of uranium from low grade and complex ore deposits, e.g., marine phosphorites, shales, coal, sea water, etc. In order to assess the potential for uranium recovery from uraniferous phosphorites, available thermodynamic data of uranium minerals, compounds and aqueous species have been collected. The existence of uranium complexes with chloride, fluoride, carbonate, phosphate, sulfate, etc., in ground waters have been evaluated at different pH's. There seems a great need to study the relative stability of these complexes in order to judge the applicability of solution mining technology for selective leaching of uranium from phosphorites. A typical flow-sheet demonstrating recovery of uranium from wet-process phosphoric acid has been included in this report. Some essential features of the economics of uranium recovery from uraniferous phosphorites have been briefly considered and recommendation have been made for further studies.

Jan 1, 1980

By S. Uludag

Spontaneous combustion of coal has been studied by laboratory techniques using an apparatus in a small-scale laboratory testing. Coal?s inherent characteristics can be measured using Differential Thermal Analysis (DTA) and Crossing Point Temperature (CPT) methods. The DTA curve obtained after testing is compared with actual inherent moisture and its effect on spontaneous combustion has been investigated. It has been found that the Wits-Ehac Index increases as the inherent moisture of the sample increases. Therefore it can be deduced that liability to spontaneous combustion increases with increased inherent moisture. In addition, volatiles have a catalytic affect on self heating immediately after the inherent moisture is reduced. This is identified as stage two in the thermogram. The inherent moisture has a cooling effect during the initial stages of testing and is visible in the DTA thermogram. In addition, while an increase in carbon content means an increase in Wits-Ehac Index value, an ash content decreases the likelihood of on spontaneous combustion. Keywords: Spontaneous Combustion, Differential Thermal Analysis, Crossing Point Temperature, Moisture, Coal, Laboratory Testing.

Jan 1, 2007

[ ] ALVA L. SMITH RMCMI PRESIDENT 1989-1990 on behalf of the RMCMI Board of Directors and Officers of The Rocky Mountain Coal Mining Institute cordially invites you and your family to attend the 86th Regular Meeting and Convention to be held June 24, 25 and 26, 1990 at Sheraton Steamboat Steamboat Springs, Colorado

Jan 1, 1989

With the advent of the environmental "green" movement of the 1960s, eventually leading to Earth Day 1970, Congress responded by passage of the National Environmental Policy Act (NEPA), 1970. NEPA gave impetus to a flood of federal acts and laws in the subsequent three decades. Many of those protecting man's environment, health, and well-being also affect mining. For purposes of this chapter, a current mineral law summarization lends itself to a division into two parts: viz., Part I, General Mining Law, and Part II, Enviromining Law. The word enviromining has been coined by the author and is defined and used herein as those federal and state statutes and regulations that were created to provide protection and preservation of man's environment, health, safety, and welfare, and they have particular application to and affect on mining activities. They are listed and treated under Enviromining Laws in Part II. Mining, as a basic industry to provide the essential minerals for mankind's necessities and well-being, truly reflects the mining industry's slogan, "If it can't be grown, it must be mined." Without the basic minerals and rocks won from the earth by mining and mineral processing for their valuable physical properties or chemical constituents, man would soon be forced to revert to the cave-dwelling age. Unfortunately, for man to survive in the "manner of life to which he has become accustomed," he is caught between the demands of cleaning up his deteriorating environment and a continued supply of his basic requirements and amenities for daily living supplied by mining of the earth's minerals. He must have "clean living" at the same time with "good living;" neither is expendable. A very high pricetag accompanies this essential and critical choice which must be paid by society. The United States is internationally recognized as the world leader in environmental matters. Many countries are following suit, principally the other Anglo nations. Because US law is founded and based on English law, on occasion, Anglo-American law is referred to and cited as authority in litigation anywhere in the Anglo-American world of jurisprudence. For this reason, and because mining and the industry is international in nature and operations, some British Commonwealth cases will appear in various topics. If the case is of interest to the reader, further inquiry at a law library may be made through use of the case's style and citation given. "Style" refers to the name of the litigating parties. "Citation" refers to the law publication in which the case and decision may be found, as well as the jurisdiction and court of decision. Citation of cases from the United States and British Commonwealth nations is explained under Case Citation Explanation. Space and time limit exhaustive treatment of subjects and covering all geographic and jurisdictional areas. This chapter is intended as a broad outline and is based on the author's master's thesis at the University of Missouri-Rolla, 1992. The following Case Citation Explanation provides guidance on formatting of citations.

Jan 1, 1994

By Arthur R. MacPherson

Este capítulo revisa las etapas que deben seguirse desde el momento de considerar la molienda autógena en el desarrollo de un nuevo depósito de mineral o en la expansión de una planta existente, hasta la compra de un molino autógeno. En este caso el término autógeno incluye: semi-autógeno, molinos de pebbles secundarios y molino de bolos (trozos), así como los sistemas de molienda autógena total. También se han incluido las alternativas por vía húmeda y seca. Antes de programar el ensayo debe decidirse cuantas muestras brutas son requeridas para calcular propiamente las posibilidades de molienda autógena del depósito. También ha de tomarse la decisión, de como y donde deben tomarse las muestras, por ejemplo: planta piloto situada en el sitio de localización de la planta o en otro lugar establecido; molienda en húmedo y/o en seco....etc. En el mismo programa del ensayo se obtendrán ciertos datos fundamentales. Los ensayos deberán incluir un trabajo suficiente. para determinar cuál de las moliendas, totalmente autógena o semi-autógena, debe utilizarse; y qué tipo produce la máxima eficacia en la potencia consumida. También, los otros datos pertinentes deben ser recolectados, como por ejemplo: potencias, tonelajes, alimentación, carga, tamaño del producto, carga circulante, etc. Si es necesaria una molienda secundaria para obtener el tamano final, la decisión de qué molienda debe emplearse (molino de pebbles o molino de bolas) puede requerirse un ensayo de trabajo adicional. Finalmente, la concentración del mineral puede jugar un papel importante en la selección del circuito y debería ser una parte del ensayo final una vez que se ha establecido la molienda. Para determinar qué tipo de molinos pueden satisfacer los requerimientos establecidos por la planta piloto, debe tomarse una escala para ciertos datos como: potencia del molino, consumo de acero, simple o doble etapa de molienda, tipo de molino secundario. Para asegurar un posterior entendimiento del depósito de mineral y sus características de molienda, deberán efectuarse algunos trabajos adicionales a pequena escala utilizando pequeñas muestras y molinos para producir unos datos comparables de molienda. También, algunos ensayos tales como medio de molienda óptimo, e índice de trabajo, deberán ser completados.

Jan 1, 1982

By C. E. Wood

[Because of the renewed i~,ortanc of the strate ic netal ~ngane8e the Bureau of Mines is conductin further ro~aarch on pyrometallurgica1 ~ethods of boneficiating 0 ngani.foro'l iron ores nnn lo\,f-~~r de oanganesc ores. Published data on .the l2~roI'let llurgica.l treatnent of tl::1.nganse8 ores have been revi .. \-'en by Jose-ph ? .2]

Jan 1, 1940

By Paul C. Hyndman

Three properties in the Tuolumne River RARE II area, the Eagle Bluff Mine (lode) and the Indian Creek Bar and Bossy Bar Prospects (placer), have identified subeconomic gold resources (table 1). Nineteen other properties have potential for gold resources. Adjacent to the study area, five properties have identified mineral resources, and nine others have potential for resources. Properties having high-grade zones (shoots), but licking enough tonnage to be classified as resources, are listed in table 2. Gold, in lode and placer deposits, is the principal mineral commodity in the Toluene River study area. Ten properties within the RARE II boundary have gold-rich zones or shoots; they range in size from 12 to 2,500 tons and in average grade from 0.09 to 0.97 oz gold per ton.

Jan 1, 1983

By Fred S. Karn

Inhibitors are used in coal mines as a precaution against accidental dust explosions. Although rock dust is the usual inhibitor many others have been tested. To facilitate testing a screening process using laser irradiation was proposed. The procedure includes irradiation of a coal-dust mixture followed by mass-spectrometric analysis of the evolved gases and an evaluation of the flammability characteristics of the gases. Carbonate-type inhibitors decreased the percentage of combustibles in the gases generated and inhibitors like NaCI (thermally stable salts) decreased the total gas generated. A suitable test procedure did not result from the investigation, demonstrating the inadequacy of fast heating, non-combustive techniques in rating inhibitors of coal dust explosions.

Jan 1, 1973

By W. Stumpf

Mill log analyses and complementary hot deformation studies were carried out on the as-cast structure and on a hot rolled structure of the same low carbon steel (SAE 1006) that had been processed according to the direct or hot charge route in a compact strip plant. The main softening mechanisms during hot rolling were found to be complete dynamic recrystallization during each pass above about 1000°C for the as-cast structure with an austenite grain size of 277µm and, secondly, incomplete static recrystallization after each pass with a finer austenite grain size of about 26 µm and tested below 1000°C. A two-stage hot working mechanism has also been found by others on a similar steel also processed by the hot charge route and this may appear to be a characteristic of this type of material. Constitutive constants determined from hot working studies were combined with other constants from the literature and incorporated into a grain size development model that correctly predicts the final ferrite grain size in the hot rolled strip steel. The predicted incomplete static recrystallization during the last three finishing passes in the plant appears to result in some retained strain in the hot rolled austenite as it transforms to ferrite on the run-out table. Analyses with the model predict relatively little sensitivity of the final ferrite grain size to process and product variables such as temperature and strain per pass for the last three passes and also the starting austenite grain size in the slab. Keywords: Low carbon steel, hot rolling of strip steel, rolling mill log analyses, austenite grain size, ferrite grain size, grain size modelling.

Jan 1, 2003

The theme of this Conference is 'The Future of Mining in New Zealand' to be addressed at a time of deepening economic concern. To ensure the assessment and development of our mineral resources in a competitive, safe and environmentally acceptable way a modest supply of a rare commodity û the professional mining engineer û must be assured. This paper briefly' reviews the history of mining education in New Zealand, discusses relevant overseas academic concerns and actions and discusses recent local trends which have led to a most serious recruitment position in the Department of Mining Engineering at the University of Auckland. Conclusions are drawn and proposals made which may remedy this situation which could have serious economic and sociological consequences for New Zealand.

Jan 1, 1991

By R. Kuyvenhoven, A. Parbhakar-Fox, X. Prieto, J. Quevedo, L. V. Danyushevsky

This paper presents the results of a study focussed on determining the distribution of cobalt in different types of pyrite of the La Estrella IOCG deposit in Chile. In the IOCG mineral deposits, where copper is the main product, the quantification and distribution of cobalt is required to correctly define the technical and economic viability of recovering cobalt as a by-product. In the La Estrella mineral deposit, seven alteration and mineralisation events were recognised through both optical and automated electronic mineralogical analysis. Of these seven events, five different types of pyrites were identified, each with unique characteristics of the pyrite crystals. Through advanced elemental analysis of these five types of pyrites, it was determined that the concentration and distribution of cobalt within the pyrite crystal is dependent on the mineralisation event. The results indicate high cobalt concentrations in the early pyrite mineralisation events, associated with relatively fine pyrite grains, and cobalt generally occurring in a solid form in the pyrite core. The late pyrite mineralisation event exhibits the lowest concentrations of cobalt, with cobalt predominantly present along the outer periphery of the pyrite. These results are relevant from a metallurgical point of view because the preferential location of cobalt within the pyrite crystal will influence the maximum metallurgical recovery of cobalt. For this, a cobaltiferous pyrite concentrate must be formed which, according to the characteristics of pyrite, must be processed with the optimal solubilisation method. The overall objective is to ensure both good cobalt recovery and a high concentration of cobalt in the leach solution resulting from pyrite leaching. Keywords: Cobalt, pyrite, IOCG, copper, metallurgical recovery, solubilisation, Chile

Jan 1, 2020

By Irving Cadoff, Kurt Komarek, Edward Miller

Barium can be purified by equilibration with titanium. The melting point of barium was found to be 726.2° i 0.5 °C. The room-temperature lattice parameters of BaTe and Bask are 7.004 * 0.002A and 6.600 * 0.002A. Melting points for BaTe and Base were found to be 1510° * 30°C and 1830° ± 50°C, respectively. HIGH-purity barium and its compounds are difficult to prepare because of the reactivity of barium with the atmosphere and the large heats of formation of the compounds. Purification of barium by vacuum distillation,' and the preparation and properties of barium oxide2 and barium sulfide3 have been reported. However, little has been done on the homologous compounds barium selenide and telluride. PURIFICATION OF BARIUM Distilled barium obtained from King Laboratories was used as the starting material. The analysis supplied with the metal showed the presence of: 0.4 wt pct Sr, 0.001 pct Mg, 0.02 pct F, 0.003 pct Cu, 0.005 pct Na and less than 5 x 10-3 wt pct of any other metallic impurity. Analyses for oxygen and nitrogen were not available. Since there is evidence4 that any barium nitride present in the starting material may decompose on distillation producing nitrogen which can contaminate the distillate, further purification was performed. At elevated temperatures, any nitrogen and oxygen present in barium should be removed by reaction with titanium. Assuming that the solubility of oxygen in liquid barium is negligible near the melting point of barium, any oxygen present will be in the form of BaO. Removal of oxygen from molten barium is expressed by the equation: BaO(S)+ TixOy(S) = Ba(l)+ TixO(y+1)(s) where Ti,Oy and TixO(y+1) are solid solutions of oxygen in titanium. At 1000°C, the change in free energy for this reaction is negative for (y+1)/x +y+1) x (100) 17.5 at. pct O.5 Since reaction with commercially pure titanium (containing 0.07 wt pct oxygen) results in a free energy change for the reaction of -19 kcal per g-atom, slight solubility of oxygen in barium would not hinder the oxygen removal. Since comparable thermodynamic data are not available to permit calculation of the partition of nitrogen between liquid barium and titanium, a similar quantitative relationship cannot be obtained. However, on the basis of work by Kubaschewski and Dench,5 complete removal of nitrogen from liquid barium can be expected. Since the melting point of barium is depressed markedly by small additions of nitrogen,' the change in melting point during reaction of barium with titanium was used to follow the purification reaction. MELTING POINT OF BARIUM A 50-g sample of barium was sealed by arc welding under argon into an all titanium crucible provided with a thermocouple well. The melting point of the sample was determined by thermal analysis, using a Pt/Pt-10 pct Rh thermocouple which was calibrated according to National Bureau of Standards specification6. The crucible was then heated for 48 hr at 950°C in vacuum and the melting point redetermined. This procedure was repeated until three successive thermal analyses agreed within ±0.5oC, the limits of error of the analysis. The melting point increased from an initial value of 720.0°C to a final value of 726.2°C. Analysis on samples quenched from 950°C gave a solubility value of 0.004 wt. pct Ti. Assuming that the titanium-barium phase diagram is similar to those of titanium-magnesium7 and titanium-calcium,8 the solubility of titanium in liquid barium decreases with decreasing temperature. Therefore, the solubility of titanium in liquid barium should be less than 0.004 wt. pctat the melting point (726oC), and the effect of dissolved titanium on the melting point would be negligible. Addition of up to 3 wt pct Sr does not significantly change the melting point of barium,7 so that the effect of the 0.4 wt pct Sr in the starting material will also be negligible. The value of 726.2" ± 0.5C obtained for the melting point of barium can be compared .with a determination carried out by Keller and coworkers in low-carbon steel crucibles,' who obtained a value of 725± 1C, using barium purified by fractional distillation. The higher value obtained in the present investigation is indicative of the effectiveness of titanium in removing traces of nitrogen. PREPARATION OF BaTe AND Base The compounds were prepared by direct reaction

Jan 1, 1961

By Fredy Llerena B.

El presente trabajo describe la geología del depósito minero Candelaria, perteneciente al distrito minero de Castrovirrey, Huancavelica. Dicho depósito está asociado a la actividad ígnea de centros y domos volcánicos del terciario medio o superior, mientras que la veta Candelaria está constituida por tetrahodrita, enargita, boulangerita, bournouita, jamesonita, esfalerita, galena, bismutinito, chalcopirita y como minerales de ganga, pirita, cuarzo, barita, oropimente, regelgar, marcasita, arsenopirita, así como hay lazos cimoidea. De otro lado, las intersecciones de vetas favorecen la mineralización y el Domo Volcánico Candelaria es favorable a la mineralización al igual que los tufos.

Oct 14, 1980

By Kenneth C. Ko

An engineering investigation was carried out on the technical and economic feasibility of implementing flexible liner/backpacking support systems In an advancing tailgate longwall mine. The system for a model mine consists of a circular tube constructed of liner plates and flyash backpacking. Flyash is pneumatically stowed into the tailgate. Small amounts of cement may be mixed to improve the support capability of the fill In difficult local ground conditions. Water is added inside the nozzle immediately prior to spraying. Results of theoretical analyses and a field test show that the designed system is technically feasible, can be cost-competitive, provides more stable ground conditions, and can Increase productivity and coal recovery, when compared with existing retreat longwall systems. In certain mine layouts, the new system can reduce the direct mining costs by a significant amount. The system would be particularly applicable to deeper coal beds with bad ground conditions.

Jan 1, 1980

By Patrice Favreau, R. F. Ph. D. Professor Emeritus Favreau

After Nobel invented dynamite, blasts were carried out by trial and error, without the use of equations based on the fundamental principles of Chemistry and Physics, although everyone accepted that shock waves were involved; but no equations were available to calculate their intensity. Around 1950 however, M.A. Cook proposed a procedure to calculate the thermochemistry of an explosive, and thus evaluate theenergy released during the explosion of a fully confined explosive. Some blasters then began to use theEnergy Factor; the latter, however, does not subdivide the energy into its three kinds of activities necessaryfor a successful blast, as demonstrated in 1968 by reference 2, namely i) the shock wave which weakensthe rock; ii) the stress field SS which fully fragments the rock; and iii) the release of the stress SS whichcauses the fully fragmented rock to burst out with the velocity necessary to move the rock into the muckpile. The article explains that the way to achieve a successful blast is by insuring that the explosive energy divides properly into the weakening action of the shock wave which is necessary to prevent large collar blocks and toe, and into adequate stress field intensity SS which is necessary to obtain good fragmentation size distribution at the crusher, as well as adequate burst out rock movement to achieve easy mucking.

Solid Energy New Zealand Limited has grown significantly since becoming a State Owned Enterprise in 1987. Exports, profit, turnover, output per employee are all trending upwards. The company has identified the management of Health and Safety as a key capability to sustain future growth, and to add value to the business. It has set a target of being the best practice in managing Health and Safety.   This paper examines the company's activities in the Health and Safety area, and how it sees that value can be added by preventing and containing losses through accidents involving people, property, process and the environment. Solid Energy is confident that a Planned approach to managing Health and Safety can achieve this. It will explore historical events, strategic changes, Health and Safety systems, Benchmarking, Performance Measures, initiatives, progress to date and challenges for the future.

Jan 1, 1997

By Kjell Winther

"Hydralift Scanmec introduced early in the eighties a new and different mill design for very large grinding mills. The design described has actually no size limitation upwards and is so far suggested with motor power up to 40 MW. The mill is furnished with gearless ring motor drive transmission. It is totally fabricated, without heavy castings. The first installation, an 8, 1 MW ball mill dia. 6,5 m x 9,65 m length, has been in continous operation in 13 years without problems. Total grinding costs has been reduced with 3 0% compared to traditional smaller mills. Reductions has been achieved in maintenance cost, power consumption, liner wear and grinding media consumption.So far 3 ball mills of the described design are delivered and in operation, one grinding Iron ore and two grinding Nickel ore.IntroductionThe design of mills for mineral ore dressing has basically been unchanged since grinding in mills started some I 00 years ago, in spite of the fact that mills have grown larger and larger. This has resulted in structural and mechanical problems, causing expensive failures and loss of production.Hydralift Scanmec engineers were designing mills for more than 20 years according to the old «rules». As they experienced interest for an increase in the mill size at the time when reports about failing mills were published, they started analyzing the different mill parts to find new solutions. One goal was to only use elements from proven technology in the new design. Two key items were ring motor (wrap around motor)(Isch et al. 1977, Meintrup and Klein 1982, Ranze 1983) and large diameter pad bearings (wrap around bearings)(Fuller 1984), both acknowledged from other industries."

Jan 1, 1995

By E. P. Youngman

This paper presents one of a series of digests of foreign mining legis- ation and court decisions that is being prepared in advance of a generel report elative to the rights of American citizens to explore for minerals and to own nd operate mines in various foreign countries. This interpretation of the laws of Demark and her possessions, has been prepared entirely from answers made by Ernest L. Ives, American charge d'effaires, Copenhagen, to a questionnaire ini- isted by the United States Bureau of Mines and transmitted through the courtesy of the Department of State.

Jun 1, 1932