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By Roger Frank

"Abstract After noting the importance of standardization for piles, the European system is described (execution, tests and design, etc.). Some important aspects of Eurocode 7 are outlined (like the role of pile load tests). Finally, the calculation methods in the recent French standard for the design of piles following Eurocode 7 are shortly addressed.Importance of standardization for piles Like for other fields of geotechnical engineering, pile engineering is a complex art. For piles, the challenges are particularly numerous and many things must be mastered properly: - the soil investigation must be serious and adequate (for instance, deep enough!);- the choice of the pile type and the assumed behaviour must be assessed in order to reach a safe and economic design of the overall foundation;- the execution itself (construction and/or installation) deserves special attention and must follow strict state-of-the art rules.The geotechnical engineer, in charge of the design of a pile foundation, must have in mind the parameters linked to the variety of soils, of soil conditions and of pile types. A wide range of strong environmental issues are also to be considered: minimum disturbance during the execution processes, long-duration friendliness of the “inclusions” into the ground (to avoid pollution of the soils and waters, for instance) and respect of the neighbouring structures.Pile engineering plays in a world which is constantly moving and progressing: constructions expand in new difficult areas, actions on piles are more and more important, new execution techniques of piles are developed, research into the complex behaviour of pile foundations has no end, etc. Our views on how piles and group of piles really work are constantly evolving!"

Jan 1, 2014

By Clark K. N

The need for and advantages of simulators in iron ore pellet induration research are described. The approaches to simulation and the techniques to carry it out are discussed in detail covering drying and firing for the straight grate process. The CSIRO simulator design is described and some errors in simulation are discussed.

Jan 1, 1974

By Lyden, Joseph P.

THE Picher Mining Field, fig. 1, which lies between Baxter Springs, Kansas, and Commerce, Okla., is the most intensely mineralized and the largest zinc-lead ore producing area in the Tri-State District of Missouri, Kansas, and Oklahoma. It has a vast lateral extent of underground workings that is unequaled for the observation of the geology of zinc-lead ore bodies in sedimentary horizons; and thousands of churn drill holes in the unmined areas supplement the underground observations with useful data for the interpretation of the geology. This paper is confined to the ore deposits of the Picher mining field. The reader is referred to the bibliography for the general geology of the Tri-State district which has been ably covered by many geologists. The writer was co-author of several publications on the Tri-State district.- This paper is necessarily a repetition of parts of those publications but contains a few changes and additions on the deposition of the minerals. The parts of this paper concerning mineralization maps and pipe slump-structures are not covered in the above publications.

Jan 1, 1950

By E. M. Watkin

"Land directly disturbed by hard rock mining activities in Ontario and Quebec was surveyed in 1974 as part of a country-wide assessment, (Murray 1977). Some 15, 000 hectares, or 5 7 square miles, are listed as having been disturbed by overburden removal, waste rock and tailings deposition (Table 1) in the region. That area represents sixty-eight per cent of the total area which ha1; been disturbed by mining in central and Atlantic Canada. Assessment of disturbed areas was undertaken using LANDSAT-1 and LANDSAT-2 satellite imagery. Certain limitations of the technique were recognized but the data obtained were considered a relatively acceptable assessment of the extent of disturbed areas larger than ten hectares.Approximately ten per cent of the land disturbed by mining in the two provinces has been reclaimed to varying degrees. Indeed, this proportion is correct for the country as a whole. As pointed out by Ripley, Redmann and Maxwell (1978), some of the land was disturbed long before environmental concern 01· reclamation were ever considered. In numerous instances reclamation will remain impossible until presently active operations are closed. Nevertheless, these authors feel such figures make it clear that reclamation has not been a high priority in Canada in the past. Canada is a vast country, and there has been little pressure toward efficient use of all land space. Most mining operations occur in areas distant from the country's population centres. Under these circumstances, therefore, the pressure to reduce the environmental impact of mining is much less than in the more densely populated areas of Europe and the eastern United States, where such activity can occur in or adjacent to large metropolitan areas."

Jan 1, 1980

By Snowdowne J. B H

Rand Mines, Limited, located in Johannesburg, Republic of South Africa has recently completed feasibility studies which have lead to the initiation of two major coal strip mining ventures. A minicomputer based mine planning system was developed to perform the feasibility studies. The broad approach of this system is to utilise inter.-actively the specialist skills and interpretative abilities of mining engineers and geologists. This paper reports briefly on the outline of the system and at greater length upon certain aspects of its use.

Jan 1, 1977

By Lee M. F

The Lady Loretta lead-zinc-silver mineral isation of north-west Queensland was discovered first by Placer geologists in 1968 as a result of a geochemical soil survey. The stratigraphic position, mineralisation and rock associations of the deposit are very similar to those of the Mount Isa lead-zinc-silver orebodies. Aspects of the exploration history, geo- chemistry and structural geology of the Lady Loretta deposit, are discussed. A geometric model of the Ore Horizon is given.

Jan 1, 1974

By WILLIAM SLOAN

B RITISH COLUMBIA in its mining activities is going ahead by leaps and bounds both in development and production. Mineral production for 1925 was $61,492,242 in value as compared to $48,704,- 604 in 1924, or an increase of about 26.2 per cent. This is a new record. It is the first time in the history of mining in British Columbia that we have gone over the fifty million mark. But we have got in the habit of making new records. The year 1924, with its mineral production of almost forty-nine million was a new record. And I am confident that when the mining history of 1926 is written it will be found that we have established yet another new record and that we can report another 25 per cent increase over 1925. What is the explanation? It is not only that the world is settling down, and settling up, after the war. It is not only that in the rebuilding, the refashioning in which all nations are busily engaged, the metals that come from our mines are needed. More than anything else, at least as far as we are concerned, it is because British Columbia has the resources and the fact that the province has been fortunate in recent years in finding men with the enterprise and the vision required to push ahead the labor of their development. From the ranks of our own people in Canada we have prospectors who have faith, energy and requisite knowledge. They are combing our hills season after season and they are of the type of manhood that does not know the meaning of the word quit. More and more these men are learning the importance of the guidance furnished by geological reports, and to an ever increasing extent such reports, thanks to the valuable work of the Canadian Geological Survey, covering areas little known to man, are made available to them-but it is recognized that in the opening up of our Province, containing within itself 372,000 square miles, it is essential that we should have the cooperation of our cousins on this side of the line as well as of our fellow citizens of the Dominion and of the Mother Country.

Jan 1, 1926

By K. Drescher

Excavations in deep level hard rock mines show rheological or time-dependent deformation responses to mining-induced stresses. These are generally not as dramatic as those seen in soft rock environments, such as potash and salt mines, but these deformations can nevertheless become substantial in time. It is usual to see total excavation closure at a much earlier stage than predicted by numerical models, and real-time measurements underground have confirmed that closure takes place on a more-or-less continuous basis, with highest closure rates observed after a blast and then slowly diminishing with passing time. This paper describes laboratory tests to determine the time-dependent response of hard rocks to loading, the results of the tests, and then quantifies these effects to explain the time-dependent phenomena observed underground. The primary intention of this work is to help explain the various time-dependent deformation processes around typical deep level hard rock tabular excavations. Three mechanisms were investigated in two typical hard rock types present in the deep level gold mines in South Africa, namely Ventersdorp Lava and Elsburg Quartzite. Uniaxial compression creep studies were done as the first part of the study followed by shear creep studies on discontinuities where crushed lava and crushed quartzite as well as a natural gouge were used as infilling. The last part of the study consisted of triaxial post-failure relaxation tests. The compression creep tests and the triaxial post-failure relaxation tests showed that the amount of energy dissipated by the lava is significantly less than for quartzite. For mines operating at depths greater than 2000 m the implication is that the lava must show a greater rockburst-proneness than the quartzite. Since the lava shows a lower post-failure stress relaxation, it can store sufficient energy for multiple rockbursts, which is seen in the clustering of multiple seismic events in the deep level mines. This study provides the first data available for energy change calculations in fractured rock masses, and provides the first general indications for rockburst intensities ahead of active mining faces.

Jan 1, 2003

By C. I. Walker

Field tests at a number of large mineral processing operations have been undertaken to better understand the wear life impact of different aspects of pump design, materials of construction and maintenance procedures. Data are presented for wear rates, and typical result variability is explored. To improve the availability of pumping equipment in a milling circuit it is not only important to improve the wear life, but also reduce the variability in the wear life of components so that the incidence of premature failure is lessened. Localised gouging wear due to flow separation and turbulent eddy formation is often the point at which part-holing occurs. A number of improvements to the design of pump impeller and throatbush (suction side liners) to reduce the localised gouging wear are outlined. Also, results are presented on the use of composite materials (mix of metal, rubber and ceramic) for throatbush materials to protect specific areas against wear.

Jan 1, 2012

By Hans-Henrik Wallin

The stresses in the heads and shell of a grinding mill are largely dependent on the bending moment produced by the trunnion bearing. By using spherical roller bearings in a special narrow housing a short moment arm is obtained and the bending moment is reduced. For large mills a hydrostatic shoe bearing which also gives a short arm, can be used. Spherical roller bearings also require less maintenance and have a long service life. As the bearings are grease lubricated an automatic lubricator is used instead of an oil lube system. Service data from two Swedish mining companys confirm the fact that the above arrangements provide a long service life.

Jan 1, 1979

By F. H. Gilpin

SINCE Noah pitched his ark within and without with pitch, the use of asphalt in human endeavor has been increasing-for Noah's pitch was asphalt. Asphalt is a bituminous material found in nature, either pure or admixed with smaller or greater quanti-ties of mineral and non-mineral materials, or obtained by the refining of crude asphaltic-base petroleum under proper methods of control. Native or "natural" asphalts are scattered through-out the world, though the commercial value of the various deposits varies greatly, depending upon both their accessibility and magnitude and the quality of the material found. It is an acknowledged fact that such asphalts have been produced through natural causes by practically the same application of tempera-ture and pressure as are used in the modern refining of crude asphaltic-base petroleum. The best known of all the native asphalt deposits are those of Trinidad Lake in the Island of Trinidad, British West Indies, and of Bermudez Lake in Vene-zuela. Asphalt from Trinidad Lake, after refining to remove organic and some inorganic diluents, contains approximately 35 per cent, of inorganic residue, and the asphalt thus produced must be fluxed with lighter asphaltic or semi-asphaltic base oil to make it com-mercially utilizable. The refined asphalt obtained from the Bermudez Lake deposit contains from 4 to 6 per cent. of inorganic material which cannot be removed. This asphalt, also, must be fluxed to produce com-mercial products. Small quantities of similar materials are available in other locations. The best pure native asphalt' is known as. gilsonite and is mined in com-mercial quantities in the State of Utah. In numerous places in the United States, particularly Oklahoma and Kentucky, there are deposits of sand¬stone and limestone impregnated with bitumen, which are known as rock asphalts. These rock asphalts may be used, particularly in the paving industry, either as found or by slight fluxing; from some deposits the asphalt is extracted and marketed commercially.

Jan 2, 1923

By G. W. Preckshot, N. G. DeLisle, C. E. Cottrell, D. L. Katz

MOST crude oils contain asphaltic substances that may be naturally or artificially precipitated. In the Greeley field, California, this asphaltic bitumen is precipitated during the flow of the oil from the reservoir to the stock tank. The mechanism of such precipitation is not well understood. This paper presents the progress that has been made by using the electron microscope as a new tool and by observing the effects of the streaming potential on the formation of bitumen particles. Crude oils at atmospheric pressure viewed in the electron microscope in very thin films under a vacuum showed no asphaltic particles. A technique of preparing slides of thin films by dilution of the oil with benzene and washing in petroleum ether was used at first, and these observations showed that the solvents caused the formation of the particles, varying from 0.01 to 0.2 micron in diameter. The electrical effects of fluids flowing through porous solid were studied, with emphasis on the formation of colloidal particles by the streaming potential. The streaming potential of crude oil flowing through sand was measured and was shown to be responsible for the formation of bitumen particles. These results bring out a new phenomenon, which may occur when crude oil flows through the porous oil reservoir.

Jan 1, 1942

By Stephen H. Hall

INTRODUCTION At some point in the design and development stage of a mineral venture, the assay laboratory building, its interior layout, and major pieces of analytical equipment must be specified for construction or purchase. Even the most experienced chemist would have difficulty in proposing useful specifications without a good deal of investigation into the kinds of analytical tasks that the laboratory will be expected to address, the probable workload, and the operating time constraints. This chapter will provide a logical approach to laboratory design that starts with such an investigation. Specific examples throughout the chapter are drawn from the author's tenure as Chief Chemist at Barrick Mercur Gold Mines, Mercur, Utah, from 1982 to 1985. It is necessary to understand the nature of a modern production laboratory, and to recognize that its operations bear more resemblance to its parent processing plant than to a research, teaching, or custom analytical laboratory. The assay lab is a processing facility unto itself, where samples and reagents are the raw materials, and assay results are the final product. Its most efficient operating mode is as an assembly line, treating samples in a nearly continuous flow. Nevertheless , there are important differences between the lab and the process plant. The products - assays - are individually unknown quantities until they are "produced.' This can vastly complicate quality control compared to the process plant. Capital costs are general 1 y small compared to the plant, but the ratio of operating costs to capital costs for a laboratory is often very much higher than for the plant. This is due to the labor intensive nature of analytical work. For instance, during Fiscal Year 1984 at Barrick Mercur Gold Mines, labor costs for the laboratory staff represented about five percent of the total labor budget, while the laboratory building and equipment represented only about six-tenths of one percent of the original start-up capital. Failure to recognize both the similarities and differences between laboratory and plant operations is the foremost cause of difficulty encountered in designing a laboratory. The

Jan 1, 1986

By Charles R. Keyes

I. INTRODUCTION. FOR a period of several years, and in a large number of cases, the Metallurgical Laboratories of the New Mexico School of Mines were employed in umpire work. During this time many important local problems were solved. Against the results of careful chemical analyses of ores, assay-returns were often checked. In many cases the assay-methods of mine and custom-smelter were compared, and both often found faulty for the ore concerned. A wide range of ores was covered. Many of the chemical analyses and assays were made by Dr. F. C. Lincoln, Professor of Metallurgy, now of the Montana State School of Mines. A varied series of instructive assays was prepared by Prof. R. B. Brinsmade, now of the West Virginia State University. Single assays and given series of tests were undertaken by H. T. Goodjohn, now chief chemist to the Cia. Metalurgica de Torreon, Coahuila, Mexico; by H. J. Hubbard, now superintendent of the Butters Divisadero Mines, Jocoro,. San Salvador, C. A.; by E. D. Morton, now superintendent of the Arizona & Nevada Copper Mining Co., at Lunning, Nev. ; and by A. W. Edelen, now superintendent of the Angangueo Unit of the American Smelting & Refining Co., in Michoacan, Mexico. A critical comparison of assay-methods that were found to be followed in the case of certain gouge-ores mined in the Mimbres range in New Mexico, and about which there had been much controversy, was made by D. F. Riddell, then Acting Professor of Assaying, and now superintendent of the Providentia Mines Co. of Parral, in Chihuahua, Mexico. To him is due the credit of much that is contained in the following notes, which be has generously permitted -to be used in advance of the publication of the complete results.

Jul 1, 1911

By G. Reuben Yourt

THIS paper is chiefly a description of the improvements in dust control chat have been brought about in the assay office grinding room at Wright-Hargreaves. The fume exhaust systems are briefly included because they also are important to the health of the employees. There are three chief factors which determine the efficiency of a dust control system: First, the amount of time and thought spent in designing it. Second, how close! y it is kept up to date with the growth of the plant-a system that is adequate for the number of machines operating when it is installed may fall short of fulfilling its purpose as the plant expands. Third, unless someone is held directly responsible, a system is likely to get out of repair and gradually lose its efficiency-this can easily be detected by regular dust surveys. In designing the present system at Wright-Hargreaves, the object kept in mind was to reduce the dust concentration of all operations to a safe limit, chat is, well under 300 particles per cubic centimecer of air. By doing this, a condition would be attained chat would make it possible to discontinue the use of respirators, which at best are not very comfortable and do not remove all of the hazardous fine-dust particles.

Jan 1, 1941

Cyanide-extractable gold is far more meaningful in the definition of ore, and control of extraction, than fire- assayable or aqua regia digestible gold. The use of cyanide- extractable gold addresses the significant problems of over- as well as under-assaying by fire and aqua regia digests. The problems of conventional control or diagnostic cyanidation extractions: lengthy extraction, and masking by pregrobbing in cyanidation extractions for assay purposes; are surmounted with a novel activator - Leach WELL. Full extraction of liberated gold, insignificantly affected by preg-robbers, can now be achieved within 30 minutes. This can assist in reducing common gold losses presently often hidden by inappropriate mine call factors, and/or high grade cut values. This paper includes a discussion of fundamental mechanisms of cyanidation, preg- and assay-robbing, which underlie the phenomena Involved.

Jan 1, 1992

By L. Alagha, J. L. Corchado-Albelo

To address the U.S. Department of Energy’s critical minerals strategies regarding rare earth elements (REE) in the U.S.A. This study evaluated apatite-rich mine tailing from the historic Pea Ridge Iron Mine (PR) for possible enrichment of REE by the froth flotation process. Comprehensive characterization studies were performed on the tailing samples to quantify the REE content, identify the REEbearing minerals and their liberation behavior. The aforementioned characterization studies were: x-ray fluorescence analysis (XRF), inductively coupled plasma mass spectrometry (ICP-MS), and TESCAN’s Integrated Mineral Analysis (TIMA). The ICP-MS analysis showed that the concentrations of heavy-REE and light-REE were 8000 ppm and 3000 ppm, respectively. TIMA showed that monazite was the major REE-bearing mineral. Additionally, it was shown that monazite and other REE-bearing minerals were strongly locked within larger apatite grains. Findings from the characterization studies suggested that REE could be enriched using phosphate minerals’ direct froth flotation process. Flotation feasibility tests were performed using selected organic and inorganic iron oxides’ depressants, including polyacrylamide (PAM), in-house synthesized hybrid polyacrylamide (HyPAM), chitosan, sodium silicates, and corn starch. Results showed that the depressant’s efficiency at pH 9 was in the following order: HyPAM > chitosan > PAM > sodium metasilicate > corn starch. Zeta potential studies on the selected depressants indicated that chitosan had the highest adsorption on magnetite’s surface at pH 7. Therefore, additional batch flotation experiments using chitosan as an iron oxides depressant were conducted as a function of chitosan dosage. Results indicated that the highest P2O5 recovery of 55% and grade of 28 wt.% were obtained at 150g/t of chitosan. However, the concentrate’s highest total REE enrichment of 1.07% was achieved at a 200 g/t dosage of chitosan. The low enrichment of REE highlighted the complex mineralogy of the PR tailings and the need to implement additional beneficiation strategies before and after the froth flotation process.

Mar 2, 2022

By Terence M. Gordon, Mati Raudsepp, Gregory M. Dipple

Four methods of measuring mineral abundance in a rock are examined for their potential in assaying for high-tech industrial minerals. One method uses X-ray powder-diffraction data and the other three rely on whole rock chemical data and information on mineral assemblages and mineral compositions. All four methods were employed to estimate wollastonite content in diamond drill core of skarn collected as part of an exploration program and are compared to visual estimates of wollastonite content from core logs. These techniques for assaying wollastonite span a considerable range ofaccuracy and expense, and combined, define a non-linear relationship between these variables. Accuracy increases rapidly relative lo expense up to total costs of about $50 per analysis. Assay methods in the $50-100 per analysis range have associated errors of 5-10% relative and probably suffice for most exploration programs. Improvements in accuracy above this level require a much larger investment. The most expensive assay technique (-$300 per analysis) yields the most accurate measurement of grade (relative error -1%). Its application may best be limited to periodic checks on other assay techniques and for fine-tuning ofmineral separation procedures.

Jan 1, 2001

By B. A. Massey

Sooner or later, we'll encounter a subordinate, peer, or boss that will test our management skills to the limit. The chances are good that our formal educations have not fully prepared us to effectively handle the situation, and through trial-by-fire, we have learned that the management of people is often as much an art as it is a science. Assertiveness - as opposed to agressiveness - is basically positive persuation. Assertive management techniques can help combine the art and science of managment to sell ideas, accomplish goals, direct the workforce, and generally promote the corporate - as well as our own - objectives

Jan 1, 1986

By Carlos Cristiano Carvalho Teixeira

No carregamento volumétrico de vagões, onde a variância de pesos carregados é relevante, ocorrem grandes limitações operacionais, que vão desde a percepção do volume em carregamento até a capacidade real de controle. Neste contexto, a diversidade de cenários é enorme: velocidades variadas (25% a 80% da capacidade), variação do minério, diferentes tipos de vagões, etc. Maximizar ou atingir o ponto ótimo com repetibilidade leva tempo e experiência. A solução considerou a aplicação intensa e avançada de instrumentação e recursos de automação, obtendo um resultado favorável de elevação da capacidade de controle sobre o peso em carregamento, nas diversas condições operacionais. A metodologia utilizada partiu de uma engenharia conceitual destacando o tratamento de riscos considerando as imprecisões e as técnicas avançadas de controle necessárias. Instrumentos e equipamentos também foram tratados dentro desses riscos, entre eles: balanças, radares 2D, identificação dos tipos de vagões, níveis dos silos, lasers para medições de precisão e para redundâncias, e ainda a simulação para testes do processo. Conclusão: 1. Maior capacidade de controle de peso carregado e menor variabilidade. 2. A imprevisibilidade na variação do material como desafio adicional para os automatismos. 3. Simuladores como diferencial na implantação da solução.

Aug 16, 2017