Search Documents

By M. P. Hay

"For a model to be successful it must address the concerns and needs of a target audience. Further, the model must demonstrate the same patterns of behaviour as the real system, and need only be complex enough to meet this objective. If the model is too complex it can become unusable to those who need it most.With this in mind, SUPASIM has been developed for the practical metallurgist requiring only laboratory flotation rate data as input. Some 35+ successful plant simulations have been completed since 1985. The approach of SUPASIM is to characterise an ore, organise information in an understandable way and add structure to the complex flotation situation and hence support the metallurgist to interpret the relationship between variables and optimise the flotation process.The paper describes the basis on which the model was developed and sets out to provide an insight into interpreting laboratory flotation kinetics and their physical meaning in a production plant and the influence floatable gangue has on float performance and plant design. A case study illustrates how the ratio of slow floating mineral to gangue can influence circuit design and improve recovery on a plant scale.INTRODUCTIONThere is an enormous amount of useful data in the results of a laboratory scale rate test. Each variable of fraction and rate, for mineral, metal and gangue has a physical meaning in the plant. The link between float kinetics and the plant in respect of recovery, grade, pulp density, pulp flowrate, residence time, number of stages of cleaning and circuit configuration has been established by the author in the process of developing SUPASIM."

Jan 1, 2005

It cannot be said that accurate and reliable ore reserve estimation is the fundamental of any mining operation success. Estimation techniques which are used to estimate the grade distribution of an orebody together with the assessment of uncertainty and risk have a vital influence on the success of any optimisation algorithm. Traditional estimation techniques such as kriging or inverse distance weighting are frequently used for assigning grade values to blocks. Various attempts have been made in order to compare geostatistical estimated methods for ore reserve estimation. This paper aims to evaluate the sensitivity of different estimation methods over changing the block dimension. For this reason, several block models with different dimensions were derived in Chador Malu iron ore mine which is located in 180 km northeast of Yazd in the centre of Iran. Each block model was estimated by different estimation methods such as nearest neighbours (NN), inverse distance (ID) and ordinary kriging (OK). The results of each estimation methods were compared against a control block file created by using the assay results of all blastholes drilled in the ore over four benches of the pit. The results signify that by estimating the large block size, no significant improvement occurred due to the employment of different estimation techniques. Furthermore, the grades estimated based on ID method is more reliable, but OK methods estimated more accurate tonnage.

Dec 6, 2010

By Clinton C. Knox

Attention of mine operators and engineers in the Picher zinc-lead field has been drawn increasingly in recent years to marginal ore deposits lying at greater than normal depth below surface in the marked structural depressions known as the Miami and Bendelari troughs. Not only mining but prospect and development drilling is relatively costly in the bottoms of the structural depressions known as the. Miami and Bendelari troughs which cross the center of the Picher field. Nevertheless, operations by various mining companies in recent years have shown that no insuperable problems exist, and with the gradual lowering of grade cut-offs throughout the field, certain potential deep-ore areas, previously only partly explored seemed worthy of further investigation. Some such areas were called to the attention of Bureau of Mines engineers by lease holders and operators, while others were noted in the course of Bureau's systematic investigation of Tri-State ore reserves. The writer was assigned to make a study of. those possible "trough extensions," in the course of which all available nine maps, drill logs, and prior reports were assembled. Subsequently 41 churn drill holes were bored by the Bureau in the periods October 1944 to May 1945 and October 1946 to April 1947. The general area under investigation this project is indicated on figure 1, which likewise shows its relation to nearby towns, roads, and railroads. The location of individual deposits included in the report is indicated more clearly on figure 3. Minable ore was found in only two holes, and the structural information procured by drilling was less encouraging than anticipated. This report, however, presents all factual data obtained, in the belief that they may be useful in subsequent prospecting and development projects in the areas investigated. There are also set forth some of the stratigraphic data relative to the Picher field ns a whole and the Miami and Bendelari troughs which were assembled in the preliminary investigation of this project.

Jan 1, 1949

By D. Zhou, T. Hamano, Tsukihashi. F., W. -G. Seo

The thermodynamic properties for the CaO-CaF2and CaO-BaO systems were calculated by molecular dynamics (MD) simulation using Born-Mayer-Huggins type pair potential. The parameters of interatomic potential were obtained by fitting the thermodynamics properties of CaO, CaF2and BaO with the experimental data. The phase diagrams for the CaO-CaF2 and CaO-BaO systems were calculated by the thermodynamic properties obtained by MD simulation. The eutectic composition and temperature of the CaO-CaF2system calculated by MD simulation were about 28 mole per cent CaO and 1575K, respectively. The calculated eutectic point agrees very well with experimental data, which are about 22 mole per cent CaO and 1633K, respectively. Keywords: molecular dynamics simulation, thermodynamics, phase diagram, calcium oxide, calcium fluoride, barium oxide.

Jan 1, 2004

By K. R. Gardner, P. B. Altringer, R. H. Lien, B. E. Dinsdale

The Bureau of Mines, U.S. Department of the Interior, is investigating chemical and biological decontamination of complex wastewaters such as tailings pond water containing 280 ppm CN and 5 ppm Se as well as significant concentrations of arsenic, copper, iron, silver, and zinc. The most effective chemical procedure involves cyanide oxidation using hydrogen peroxide or sodium hypochlorite followed by selenium reduction using ferrous hydroxide. The effluent contains ?1 ppm CN and 20 ppb Se; concentrations of other - major contaminants meet National Drinking Water Standards. Preliminary research indicates that biological cyanide oxidation is possible even in highly alkaline solutions (pH 10.5) containing high cyanide concentrations; indigenous bacteria destroyed 85% of the cyanide. Exploratory research shows that other bacteria removed up to 79% of the selenium from chemically oxidized, low- cyanide water. These promising results may lead to a final processing scheme that involves a combination of chemical and biological techniques.

Jan 1, 1990

By Joseph L. Margin

From a stubborn start to record setting performances in little over a year, that is the story of the English Running Tunnel Boring Machines. The program to transfer technical information on these highly advanced machines from builder to user will be discussed as a vital link to this accomplishment. Some interesting features of these machines will be covered as well as a recounting of the various conditions that were encountered during these drives and how they were resolved.

Jan 1, 1991

By V. B. Achanti, A. W. Khair

Laboratory studies were carried out at West Virginia University to investigate the rock fragmentation mechanism by continuous miners using an automated rotary cutting simulator. The primary factors influencing the fragmentation process were found to be: bit spacing, bit geometry, depth of cut and cutting drum rotational speed. This paper presents the influence of these parameters in achieving optimum energy consumption and minimizing dust generation during rock fragmentation process. Tree bits were used simultaneously on Indiana limestone while the bit tip angle was varied from 60° to 900. Bit spacing was varied from 2.54 cm (1 in.) to 5.08 cm (2 in.) while the cutting process was assessed for varying cutting depths. Restorable dust generated during the course of the experiments was analyzed utilizing cascade impactors. Assessment of these parameters has led to a better understanding of the cutting mechanism by continuous miners in terms of energy consumption and dust generation.

Feb 24, 1997

By R. Ribacchi, P. Tommasi, C. Consorti, P. Campedel

The runout of dry blocky rock avalanches produced by planar rockslides affecting a limestone formation with clayey interbeds is analysed by means of distinct element modelling. Numerical analyses are validated by means of the back analysis of a historical rockslide occurred in the investigated area and physical aspects of the phenomenon evidenced by modelling are discussed. On analyse par la méthode aux élements distincts la distance de parcours des avalanches rocheuses sèches produites par des glissements plan interessant une formation de calcaire à intercalaires argilleux. Les analyses numeriques sont validées à l’aide de la back-analysis d’un glissement historique survenue dans le site en examen. On décrit les aspects physiques su phénomène mis en évidence par la modélisation efféctuée. In diesem Beitrag wird die Reichweite von Steinlawinen besthend aus trockenem blockhaftem Fels mittels der Distinct Element Methode untersucht. Die Steinlawinen werden erzeugt von Rutschungen in einer Kalkstein-Formation mit tonhaltige Schichten betreffen. Die numerischen Berechnungen wurden anhand einer Simulation einer historischen Bergsturzen verifiziert, der sich auf den untersuchten Gebiet ereignete. Auf der Basis der erhaltenen Ergebnisse wurden die physikalischen Aspekte der untersuchten Steinlawinen analysiert.

Jan 1, 2003

By K. Pirapakaran

The Geotechnical Engineering research group at James Cook University has been working closely with all the leading mines in Australia in the area of minefills. They have carried out substantial research and consulting work on the drainage and stress developments within hydraulic fills. The objective of this paper is to summarize their work during the past five years on hydraulic fills. The paper will serve as a one-stop reference, pointing to relevant literature including the authors? own publications, on various issues covering drainage and stress developments within hydraulic fills. More than 15 different hydraulic fills, representing five major mines in Australia, were studied. Their grain size distributions and placement characteristics including permeability, porosity and dry density were studied and comparisons were made with the limited in situ data available in the literature. Stress development within hydraulic fills has been studied to minimize the risk associated with barricades failure. FLAC and FLAC3D were used to model stress developments within the hydraulic fills and were compared against the approximate closed form solutions available in the literature. A laboratory model was developed to study arching effects within the hydraulic fills.

May 1, 2007

By L-B Fu and J Tan, J H. Wei, N Tian

"An EXTENDED ABSTRACT is available for download. A full-length paper was not prepared for this presentation. The Kendenggaoer-Kuokuqueke region lies in the western part of Chinese North-western Tianshan. New laser ablation inductively coupled plasma mass spectrometry zircon U-Pb geochronology for five separate granitic plutons for this region reveal two distinct intrusive periods: late Devonian (367~361 Ma) and late Carboniferous (315~301 Ma). These intrusions all share an arc-like geochemical affinity (ie enrichment of large ion lithosphere elements and negative anomalies of Nb, Ta and Ti). In situ zircon Hf isotopic compositions further differentiate the magmatic cycle, with the late Devonian intrusions yielding more depleted eHf(t) (+1.47~+6.54) composition than the late Carboniferous intrusions (eHf(t) = +4.95~+9.79). These geochemical data suggest that they might be mainly derived from different source regions and the tectonic setting was transformed into post-collisional in the late Carboniferous. As in many significant porphyry-ore districts, this dramatic tectonic reconfiguration, combined with melting of an evolved crust, resulted in genesis of metal-bearing melts. Furthermore, we can show that Neoproterozoic mafic juvenile lower crust intruded by mantle-derived melts and/or partial melting of slab material generated hybrid primary magma during subduction of the Palaeo-Junggar oceanic crust in the late Devonian. Whereas underplating of mantle-derived magma contributed more to the Late Carboniferous post-collisional magmatism.CITATION:Tian, N, Wei, J H, Fu, L-B and Tan, J, 2015. Timing and geodynamic setting of the late Palaeozoic polymetallic mineralisation in Chinese north-western Tianshan – insights from geochronology and petrogenesis of granitoids , in Proceedings PACRIM 2015 Congress, pp 171–174 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Mar 18, 2015

By P. B. Ritter

The feasibility of redesigning and adapting the all- secondary-explosive, low-voltage, electric safe detonator for use as a delay detonator has been demonstrated. Experimental results have shown that operational characteristics can be adjusted to allow direct competition of safe delay detonators with commercial delay blasting caps. Five different experimental delay period models have been developed and tested. Test results are given and results are evaluated. Subsequent simplified and improved designs for practical and economical mass production are described. Design concepts to meet Bureau of Mines voltage withstand, incendivity, and spark sensitivity requirements are included. Recommendations are made for experimental procedures to ready the safe delay detonator for mass production and extensive use in mining and other industries.

Jan 1, 1977

By Jr. Watts, J. L. Ambs, B. K. Cantrell, K. L. Rubow

"The University of Minnesota and the U.S. Bureau of Mines collaborated to develop and field test a personal diesel exhaust aerosol sampler (PDEAS). The PDEAS was field tested in five underground coal mines that use continuous miners and a variety of diesel vehicles, including diesel haulage and utility vehicles. One mine was surveyed a second time, with the haulage vehicles fitted with a low-temperature disposable diesel exhaust filter (DDEF). Aerosol samples were collected with a variety of instruments, including the PDEAS and the microorifice, uniform-deposit impactor (MOUDI). This paper presents the diesel exhaust aerosol (DEA) concentration data collected in these mines and assesses the impact of diesel face-haulage equipment, with and without exhaust filters, on underground mine air quality.The average DEA concentration at the haulageway location for five mines, determined by the PDEAS, was 0.89 mg/m3, with a standard deviation of 0.44 mg/m3 • DEA contributed 52 pct, of the respirable aerosol at the haulageway location. Use of the DDEF at one mine reduced DEA by 95 pct, with a standard deviation of 6 pct, and filter life averaged 10 h. DEA contributed a large proportion of the respirable aerosol concentrations in mines with diesel equipment, and a substantial reduction was achieved with use of a DDEF. INTRODUCTIONDiesel equipment is gaining popularity in underground coal mines. There are an estimated 1,951 units of diesel equipment in 152 underground coal mines compared with 1,100 units in 110 mines 5 years ago (J).5 This increased use is due to the recognition that diesel-powered vehicles are more versatile, which can contribute to increased productivity compared with their electrically powered counterparts. Approximately 33 pct of the diesel vehicles haul coal, 45 pct haul personnel and materials, and- 22 pct perform other duties, such as roof bolting, rock dusting, and road maintenance. Most mines using diesel equipment are located in Kentucky, Utah, Virginia, and Colorado."

Mar 1, 1992

By P. Raffinot, C. H. G. Bushell, S. Hodgson, E. F. Milner, H. J. Bosshardt, N. Draper, D. E. Pickett, Edwin T. McKnight, J. Prieto

Zinc ranks third and lead fourth in world nonferrous metal conumption. In 1972 the free world consumed 3,333,000 mt of refined lead and 4,422,000 mt of refined zinc. The lead tonnage was divided into the following end uses: storage batteries (42%), lead allows (7%), pigments and chemicals (11%), cable sheathing (9%), gasoline additives (13%), pipes and sheets (8%), and miscellaneous uses (10%). The corresponding distribution of zinc uses in 1972 was galvanizing (39%), die casting (26%), brass (15%), rolled zinc (8%), oxide excluding American Process zinc made directly from concentrate (6%), and other uses (6%). The pattern of usage of lead and zinc varies considerably from country to country. During 1972 in the USA 49% of refined lead was consumed in storage batteries, 19% in gasoline additives, and only 3% in cable sheathing, whereas in the United Kingdom 28% of the lead was consumed in batteries, 14% in cable sheathing, and 14% in gasoline additives. For zinc the major US uses were die casting (41%) and galvanizing (37%), with about 3% consumed as rolled zinc; corresponding usages in the same applications in France were 12, 28 and 28% and in Australia 12, 67, and 3%, respectively. The outstanding resistance of lead to corrosion, its density, and

Jan 1, 1985

By B. E. Warren

Jan 1, 1965

By X T. Nguyen

Western AustraliaÆs Mining Act 1978 was amended in 2010 to provide for the requirement of a mine closure plan to be submitted to the Department of Mines and Petroleum (DMP) for approval, as part of a mining proposal application. The mine closure plan must be prepared in accordance with approved guidelines. Guidelines for mine closure plans were developed to assist the mining industry in Western Australia to plan and implement effective closure of mines. The guidelines focus on the application of integrated mine closure principles and industry best practice information on mine closure. This, includes stakeholder consultation, risk based approach, data collection and monitoring, development of completion criteria and financial provision.Due to the potential high level of public interest in the guidelines, extensive consultation with stakeholders was conducted. The purpose of this paper is to share experiences from the consultation process.CITATION:Nguyen, X T, 2012. Mine closure guidelines for Western Australia and consultation process, in Proceedings Life-of-Mine 2012 , pp 43-46 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 10, 2012

By T S. Cochrane

This paper is based on observations made during a recent visit by the writer to three of the dust research laboratories .in West Germany, each .of which is mainly concerned with studymg the composition and character of the respirable dust produced in mines or at industrial sites. The three institutes are discussed as regards their orgamzat10n and duties, their methods of dust sampling and analysis, and recent trends in research and development. An extensive bibliography completes the paper. Introduction A RECENT trip to Europe to attend international conferences m Austria and m Belgium gave the writer the opportunity to visit a number of research laboratories and mines in Western Europe. The visits to the dust research laboratories in West Germany are the basis of this report. In Germany, cooperative associations formed prior to and since the turn of the 20th Century to promote the safety and welfare of their workers have recognized the effects of airborne dust on the general health of the labour force.

Jan 1, 1964

By Elford H. S

Mr. H. W. GEPP said he desired to bring particular attention to this paper. The underlying intention of the Development and Migration Commission when the paper was prepared was to place at the disposal of Australian miners and metallurgists the story of the development of tin metallurgy as it had been advanced in other countries, particularly Great Britain. They had very considerable resources of low-grade tin-bearing metals in the eastern coast of Australia particularly, and they need not anticipate that tin was going to remain at the extremely low price at which they saw it to-day. The Commission felt that it was most desirable to place 'on record, and make easily available, the story of the treatment of comparatively low-grade tin ores in other parts of the world.Arrangements were made that the technical staff at Australia House, in conjunction with Mr. H. S. Elford; should collect this information so that in due course, when Australia awoke to an interest in low-grade deposits, of which there were many throughout Australia, this story would then not,have to be gathered from other areas and other places of the world. The -paper was a contribution which would turn out to be of very great value. He suggested to the younger members that this thorough contribution could be made the subject of study so that they would be ready to assist in the developments which must come. Mr. WM. APLIN said there was one point in connection with the paper upon which he would like to speak. While at Mount Morgan he had occasion to test some highly pyritic tin ore by flotation, with a view to separating the cassiterite from the pyritic mineral.Instead of accomplishing that, it was discovered that it would be possible to eliminate as much as 50% of the total weight of ore in the form of a pyritic flotation concentrate, which would contain...

Jan 1, 1930

By Blanchard R

In stopes of the 2000- and 2150-ft. levels in the North mine section of North Broken Hill Limited, whence a substantial proportion of the company's production is being drawn, and especially in stopes which involve the portion known as the Northern orebody, occurs it light-coloured friable porous material which represents average grade ore from which the lead and zinc minerals, and certain gangue constituents, have been largely or wholly removed by leaching. The 2000- and 2150-ft. levels lie, respectively, 1550 and 1700 ft. below extreme base of the pre-mine oxidized zone. Composition of the cellular product shows it to be supergene. The oxidation and leaching, therefore, must be assumed to have taken place since drainage of the affected areas was accomplished by mining operations.The matter is of more than passing interest, because the post-mine...

Jan 1, 1942

By David G. Almond

"Economies of scale and the variable characteristics of many large ore deposits have resulted in grinding installations having large SAG mills fitted with variable speed drives. Problems associated with effective operation of this equipment has created the need for better operator knowledge of mill load behavior and the need for new instrumentation capable of providing accurate information about load movement and composition. This paper discusses two performance enhancing instruments available to address these needs.INTRODUCTIONThe economic demands of new mining projects has resulted in increased equipment sizes and this is particularly evident in milling where there are now many SAG mills operating in the range of 28’ – 40’ diameter with installed powers of 8 – 22 MW. These mills are designed to process very high capacities of ore daily2 and the variable characteristics of many of the deposits mined results in the need to vary the mill speed during processing to cater for the changes in ore hardness. Mill speed changes often result in operational problems associated with high-energy impacts striking the mill liners reducing energy efficiency as well as degrading the grinding media through breakage, accelerating liner wear and in extreme cases even breaking liners. These operational problems have given rise to the need to have instruments aimed at providing operators with accurate information in real time about the load composition and movement within SAG mills.The original concepts for operating SAG mills were derived from past experience of operation of conventional fixed speed ball mills. However, the relatively stable conditions that applies with fixed speed and constant ball charge in ball mills supports theoretical approaches to the grinding process based on energy calculations such as Bond’s Work Index concept. Later a set of parameters Si and Bij were used for describing load kinetics, but all of these methods neglect the details of load movement and how the energy is actually used inside of the mill. It is now commonly accepted as a basic rule that SAG mills grind by impact whilst ball mills grind by attrition and consequently SAG mills are designed and operated to generate a large amount of impacts by the cataracting load without paying sufficient attention to where these impacts are actually occurring. Many mills are operated on the basis that as long as the mill is consuming the expected power there is little attention given to the class of bodies using this energy and this often results in the inefficient use of energy."

Jan 1, 2005

By Paul M. Hall

In the last several years, the coal mining industry has made significant changes in the design of longwall mining systems to make them more productive. Some changes, such as increasing the length of the coal faces and increasing the capacity of the face conveyors, have resulted in problems with achieving sufficient motor torque to start and operate the longwall face conveyors. Other changes, such as increasing the size and/or decreasing the percent impedance of longwall power center transformers, have resulted in problems with the short-circuit currents on the transformer secondaries exceeding the interrupting ratings of the molded case circuit breakers used to protect the secondary circuits. A survey of 24 longwall mining systems in northern West Virginia was conducted to investigate both problems. The results of the survey are presented and analyzed. Several recommended solutions to the problems are presented to enable the coal mining industry to design safe and productive longwall mining systems.

Jan 1, 1982