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By X. S. Tan

This paper deals with the analysis of stress condition on the interface between two types of floor rock materials when the vertical stress is larger, or when the horizontal stress is larger in a rectangular opening. It indicates that the floor Failure and the failure stress of floor rocks are closely related. It also demonstrates that a larger horizontal stress is one of the most important factors in increasing the potential for floor rock failure and floor heave.

Jan 1, 1990

By W. H. Langer

At the start of the 20th century Denver?s population was 203,795. Most streets were unpaved. Buildings were constructed of wood frame or masonry. Transport was by horse-drawn-wagon or rail. Statewide, aggregate consumption was less than 0.25 metric tons per person per year. One hundred years later Denver had a population of 2,365,345. Today Denver is a major metropolitan area at the crossroads of two interstates, home to a new international airport, and in the process of expanding its light rail transit system. The skyline is punctuated with skyscrapers. The urban center is surrounded with edge cities. These changes required huge amounts of aggregate. Statewide, aggregate consumption increased 50 fold to over 13 metric tons per person per year. Denver has a large potential supply of aggregate, but sand and gravel quality decreases downstream from the mountain front and potential sources of crushed stone occur in areas prized for their scenic beauty. These issues, along with urban encroachment and citizen opposition, have complicated aggregate development and have paved a new path for future aggregate development including sustainable resource management and reclamation techniques.

Jan 1, 2009

By Inn-Joon Park

Major problems associated predicting soil-structure interaction behavior are based on the fact that soil is neither homogeneous nor elastic and soil properties are spatially variable. There also exist significant coupling problems between the behavior of the structure and geologic media. When designing foundation or other geotechnical structures, the load transfer between the soil and structure takes place at the contact surface. This surface is called the interface. The behaviors of interface play an important role in the load-deformation response of soil-structure interaction systems. The purpose of this study is to develop improved model for simulation of saturated sand-steel pile interface behavior based on a general concept, called the disturbed state concept (DSC), which can characterize the behavior of saturated soils under dynamic loads. In this study, the Disturbed State Concept (DSC) constitutive model is calibrated and modified for steel pile-saturated sand interface and interaction by using the continuous hardening model for relative intact (Rl) state and the critical state model for the fully adjusted (FA) part in the saturated sand material. The general formulation for implementation has been developed. Then, the DSC model with modification for interface and saturated sand is implemented in finite element program based on the generalized Biot's theory. The interface tests under one-way monotonic and two-way cyclic loading and cyclic triaxial tests are executed for defining the parameters for interface and surrounding soils. Based on these parameters, steel pile-saturated sand interface and interaction are numerically simulated using the finite element program modified in this study. The DSC predictions show improved agreement with the observed results from laboratory test.

Jan 1, 2002

By Abraham Lindo

"Blasting plays a key role in hard rock underground mining. It is by nature a violent and destructiveextraction method designed to economically fragment the rock into a suitable size for it to be loaded and hauled as part of the specific mining process while controlling the amount of damage to the surrounding rock mass."

Jan 1, 2016

By S. E. Cook

This article uses the case of the Royal Bafokeng Nation to argue that royalties and dividends from mineral resources, if managed well, can provide direct benefits to the surrounding community even while the state collects its share of mining revenues through taxation. The key to this model is the effective management of the resource income flowing into community coffers. Where some of this income may fund urgent interventions in the community, a portion of the income can also be used to establish an intergenerational wealth fund to meet the needs of future generations. As a depleting resource, minerals like gold and platinum are not a sustainable source of income, and must be replaced over time by more regenerative income streams. These strategies and dynamics are manifest in the Royal Bafokeng Nation?s status as both community and quasi-municipality, a labour hosting and a labour sending community, a mine operator and a mine owner. The Royal Bafokeng Nation also owns one of South Africa?s largest community-based investment companies, which channels revenue derived from platinum deposits into a broad investment portfolio that in turn funds an aggressive social development program for 150,000 people living in twenty-nine rural villages.

Jan 1, 2013

By Slawomir Bock

One of the fundamental issues having a great influence on the safety of operations performed in underground mines is the support of workings which should assure their stability in a given geological setting and mining-technical conditions during the life of their use. The process of designing and planning support for roadways may use analytical and empirical, as well as numerical methods. In view of the rapid increase in the data processing capacity of computers and the development of more and more enhanced software for numerical modeling, it seems to be advantageous to use numerical methods in searching for design solutions ? especially in the case of non-typical mining and geological conditions and in cases that need to take into consideration a great number of factors. The assessment of rock mass quality is of basic significance in designing mine supports. Fractures, dividing the rock mass into blocks, have an essential influence on the stability of the rock mass and underground construction. This paper presents examples of the fundamental underground investigations on the rock mass conducted by the Department of Extraction Technologies and Mining Supports of the Central Mining Institute in Poland, such as: penetrometric tests, introscopic examination, laboratory testing of rock samples and ground penetrating radar. Moreover, this contribution also presents examples of applications of three-dimensional numerical modeling for the purposes of stress-strain analysis of the rock mass around mine workings and computer-aided support design by means of FLAC3D (developed by Itasca) and Cosmos/M (developed by Structural Research and Analysis Corporation).

Jan 1, 2009

By J. F. T. Agapito, R. R. Goodrich

Yield pillars have been used for many years to help reduce stresses near mine openings and improve roof and floor stability. A yield pillar is often defined as a pillar that fails but retains residual strength. Stress transfer occurs through the roof and floor after the peak strength of the pillar is reached. High stresses are transferred from around the openings onto abutments that can be barrier pillars or unmined ground. This mechanism, often referred to as pressure arching, is possible as long as the width of yield pillars is less than the critical width above which stresses cannot be carried by the overburden. Significant stress transfer also can occur due to small amounts of pillar and/or floor yielding before the peak strength is reached. This is accomplished in a quasi-elastic manner with little or no visible roof and pillar fracturing or floor heave. Long-term stability may be achieved when stresses and mechanical properties are favorable to pre-failure yielding. This paper gives practical examples where improvements in stability and resource recovery were achieved with this mechanism. Yielding was assessed by comparing measured and calculated vertical pillar stresses. Results indicated that calculated stresses in the pillars were 25 to 40 percent higher than the measured stresses, demonstrating significant arching load transfer to the abutments. Pre-failure yielding is probably often present but unintentional in both development and production areas. Better recognition and use of this mechanism should lead to improved designs as mines become deeper.

Jan 1, 2001

By M. Courchesne, C. Barbery, D. Hodouin, C. Carrier

"The carbon-in-pulp process for recovery of gold dissolved in dilute cyanide solutions, in the presence of solids, has now replaced the convedntional processes of pregnant liquid/barren solids separation followed by Merrill-Crowe precipitation. Most plants built over the past ten years incorporate a CIP section. The process is described as cheaper in capital and operating costs, and few major start-up or operational difficulties are reported. For the purpose of the present paper, the CIP process will be assumed to consist of the following sequence of operations (Figure 1):- the slurry stream coming out of the cyanidation circuit is first screened to remove any tramp oversize material. Gold dissolution is assumed to be complete before entering the CIP circuit.- the slurry is sent into a series of agitated tanks in which it is mixed with activated carbon. The carbon particles size is much coarser than the top size of the ground ore. The tanks are fitted with screens that allows the slurry to overflow continuously into the next tank, while retaining the carbon in the tank. Slurry dilution is adjusted to prevent carbon from settling in the tanks. Agitation intensity is kept low in order to minimize carbon abrasion.- carbon is transfered from tank to tank in a discontinuous manner. According to a specific schedule, the carbon from tank one is removed, then carbon from tank two is sent to tank one, and so on, till the last tank, which is filled with regenerated carbon corning from the elutionregeneration section. The amount of carbon removed, the transfer from tank to tank, the sequence of transfer, the carbon inventory in the various tanks are parameters which are, up to a point, at th2 discretion of the operators, as long as they remove, batch wise, an amount of loaded carbon containing a similar quantity of gold to the one that has entered the circuit since the last transfer."

Jan 1, 1987

This paper describes a simple finite element (FE) modelling approach which leads to the computation of seismic energy release rate (ERR) and strain energy storage rate (ESR) which result from mining. The concept of critical strain energy is introduced as a means to help evaluate the strainburst potential in mine structures. A new, energy-based, burst potential index (BPI) is proposed. The use of ERR, ESR and BPI is demonstrated by a cut-and-fill stope case study. The merits of using such energy parameters in the interpretation and analysis of strainburst phenomena are discussed. While the study gives promising results, site-specific back analyses would be required to first calibrate the model and fit it with the local mine conditions, before it can be adopted as a routine design tool.

Jan 1, 1999

By T C. Ooi, L Lu

Owing to ongoing development of new orebodies and changes to existing mining operations, new ore types with distinct mineralogy, porosity and textures are generated as feed for iron and steelmaking. Moreover, further product differentiation occurs as fine ores are increasingly beneficiated to achieve grade. A study was necessary to characterise a suite of iron ore fines in terms of their propensity for formation of quasi-particles and green bed permeability prior to sintering. In this study, two Marra Mamba bedded iron deposit (BID) samples, one Pisolitic channel iron deposit (CID) samples, two dense hematite samples (coarse and fine grained microplaty hematite), one hematite-goethite BID samples and one hematite-goethite bedded/detrital iron deposit (BID-DID) composite sample were investigated. Both Marra Mamba fines and Pisolitic fines exhibit the highest green bed permeability followed closely by hematite-goethite fines, fine microplaty hematite fines, hematite-goethite BID-DID composite fines and coarse microplaty hematite fines at a moderate sintering bed depth of 500 mm. While porous fines generally form better quasi-particles upon granulation than dense fines, the amount of moisture addition increased due to the moisture saturation of the porous fines. As sinter strands become ever larger and deeper, it was necessary to examine the granulation performance of these ore types at a range of bed depths ranging from 300 to 900 mm. On average, the green bed permeability achieved by different ore types, decreased by approximately 7.5 - 9 Japanese Permeability Unit (JPU) as the bed height was increased from 500 mm to 900 mm. In order mitigate the effect of lower bed permeability of the deeper beds, small additions of hydrated lime were investigated as a binding agent to facilitate the formation of strong micro-pellets. With the addition of three per cent hydrated lime, equivalent to approximately 2.3 per cent burnt lime, the majority of fines achieved adequate permeability for deeper bed sintering, with the exception of coarse microplaty hematite fines. In simulated coastal steelmaking sinter blends, it was found that the overall granulation performance of the blend is contributed to by individual fines constituting the blend. Therefore fines possessing favourable granulating properties impart better granulation to the blend as a whole.CITATION:Ooi, T C and Lu, L, 2013. Effects of ore type and binder addition on the formation of quasi-particles and green bed permeability at different sintering bed depths, in Proceedings Iron Ore 2013 , pp 459-466 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 12, 2013

By J. M. Benson

Titanium is an exciting structural material that can offer significant strength-to-weight advantages over currently used alloys. However, its Achilles? heel is its costly, energy-intensive production process that effectively eliminates it from competing with aluminium and high-strength steels, apart from critical applications where titanium forms only a small component of the total cost. Current attempts are being made to reduce the cost of titanium products and these recognize the importance of minimizing the costs over the total production chain. Powder metallurgy (PM) technologies play a crucial role within this, as the output of the existing and potential primary metal production methods is in the form of sponge or powder. By using PM, costly remelting and forming operations can then be avoided, except in the manufacture of large components. Metal injection moulding (MIM) is an effective process for producing complex net-shape components in large volumes from metal powders. Nevertheless, the commercial use of titanium powders in this process is still in its infancy. The only major supplier of feedstock utilizes a polyacetal-based binder. This gives good green strength but requires a catalytic nitric acid process to remove most of the binder prior to thermal treatment. As this involves additional and expensive equipment and is a potentially hazardous process, there is interest in finding an alternative binder system that can be debound either purely thermally or that involves a less hazardous, more environmentally friendly solvent. This paper describes the use of capillary rheometry to characterize the influence of temperature and shear rates on the flow behaviour of potential binder systems for titanium MIM feedstock. Keywords Titanium, metal injection moulding, capillary rheology, feedstocks, powder loading.

Jan 1, 2011

By S M. Aminossadati, R Bagherpour, F Hasheminasab

Mine ventilation is an essential part of underground mining operations used to provide fresh and cool air, as well as to dilute and remove contaminants from the work environment. This paper presents an overview of the ventilation and gas management systems in one of the underground coalmines in Iran: Parvadeh_1 mine. The mine is located in the Tabas coalfield in the South Khorasan province. It is the only fully mechanised mine in Iran utilising the longwall retreat technique. The mine produces 1.1 to 1.3 Mt of coking coal annually. The mine ventilation system currently utilises two 630 kW exhaust surface fans. The gas management system includes surface to in seam (SIS) predrainage boreholes. The underground mine is equipped with an underground gas reticulation pipeline that is connected to a surface plant for the production of methane gas. This study shows that the ventilation and gas management systems of the Parvadeh_1 mine are in line with the standards of Australian underground mines.CITATION:Hasheminasab, F, Aminossadati, S M and Bagherpour, R, 2017. An overview of ventilation and gas management systems in an underground coalmine in Iran, in Proceedings Australian Mine Vent Conference 2017, pp 41–46 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 28, 2017

Measurement of densities, susceptibilities, permanent magnetization, and calculation of demagnetization factors has allowed computer modelling of gravity and magnetic data over the Middleback Range iron formations of South Australia. As well as providing structural information, the study emphasizes the effects of weathering on the interpretation of magnetic data.

Jan 1, 1975

Gippsland has perhaps the most colourful history of exploration of any area in Australia. Hydrocarbons were first discovered in the Gippsland Basin in 1924 when a water well at Lakes Entrance encountered oil and gas shows. In 1942, the Commonwealth and Victorian Governments, in an effort to supplement a wartime oil shortage, sank a shaft near this well and produced 8000 barrels of low gravity oil up to 1956, when the field was abandoned. A total of 64 shallow wells had been drilled in the Lakes Entrance area by that time. Elsewhere in the onshore Gippsland Basin, 30 wells were drilled from 1925 to 1941. In 1960 BHP Ltd was granted an exploration permit covering much of the offshore area of the Gippsland Basin. Esso Australia Ltd joined BHP in 1964 and drilled the Barracouta-1 gas discovery in 1965. Since then over 100 exploration and appraisal wells have been drilled in the basin resulting in the discovery to date of some 3.6 billion barrels of recoverable oil and 8.8 trillion cubic feet of recoverable gas (Current remaining recoverable reserves are 906 million barrels of oil and 5.7 TCF of gas). Exploration in the offshore areas is actively continuing today and new discoveries are still being made.

Jan 1, 1992

Australian rutile and zircon concentrates are refined raw materials and not manufactured products. The composition and properties of the grains are therefore fixed by nature. Specifications and assay certificates should take this into account by eliminating unnecessary provisions which only increase the time and cost of analysis.INTRODUCTIONThe raw material from which Australian rutile and zircon concentrates are isolated is beach sand on the coast of New South Wales and Southern Queensland. The principal current operations are in an area between Sydney and Brisbane.The sands consist principally of quartz particles, but they contain from 1 per cent to 50 per cent of a mixture of heavy minerals, including zircon, rutile, ilmenite, monazite, leucoxenic grains, chrome spinel, chromite, garnets, corundum, topaz, brown spinel, olivine, epidote, clinozoisite, tourmaline, magnetite, hematite, and cassiterite. The major components are zircon (25 to 60 per cent), rutile (25 to 50 per cent), and ilmenite (5 to 50 per cent).The so-called leucoxenic grains are not a definite mineral species but an alteration product of which the major components are titanium oxides and silica in varying proportions.Primary concentration is by gravity, using spirals or various forms of pinched sluice (Pullar, 1962), the resulting concentrates being redressed on wet tables. During these processes, some of the lighter heavy minerals including leucoxene and impure rutile, which tend to degrade the final rutile and zircon concentrates, are eliminated.The separation of heavy minerals from each other is...

Jan 1, 1963

By Aurelio L. Miranda V.

Desde 1938, el estudio de La Brunquita, especie de mineral del zinc, ha conllevado diversos estudios y pruebas de flotación no solo a nivel peruano, sino internacional, a fin de determinar el procedimiento económico para su explotación industrial. En este aspecto, el objeto del presente texto señala los factores, estados problemáticos, como los resultados obtenidos durante del tratamiento del mineral en la mina de Cercapuquio. Entre los factores destacados encontramos: abundancia y ley alta del mineral, cotizaciones actuales en el mercado internacional y la labor de los técnicos. Respecto de las condiciones problemáticas que refiere las características del mineral, tenemos el difícil control rápido de la marcha de flotación, degradación del mineral e imprecisión entre el mineral y la ganga, dado el tamaño de las partículas del mineral. Finalmente, los resultados obtenidos en este proceso, muestra que para el tratamiento de pre-concentración aplicado a los minerales finos de Cercapuquio, se necesita la hidratación ya que facilita la flotación posterior del mineral. Asimismo estas operaciones de pre-concentración no solo aumentan la ley de alimentación a los molinos y la capacidad de las plantas de beneficio, sino también que modificando la composición física del mineral, mejoran las condiciones del tratamiento posterior.

Jul 20, 1956

By Rose Vera, Alejandro Luna

El programa “Fortaleciendo capacidades para la empleabilidad local” es una iniciativa que busca incrementar las oportunidades de empleo formal y digno para los moqueguanos. Con un enfoque innovador e integral, y siguiendo los principios del Plan de Minería Sostenible, permite gestionar la oferta de trabajo de Moquegua para conectarla con la demanda laboral de la región y del país, mejorando previamente sus capacidades y competencias. A través de capacitaciones en los sectores y ocupaciones con mayor demanda en el mercado, se incrementan las oportunidades de trabajo para la población local, más allá de la minería.

Sep 29, 2023

A comparatively new and very promIsmg field for applying cemented tungsten-carbides is in the mining and quarrying industries. The economic advantages of this unique engineering material over the conventional hollow drill steel, or steel detachable bits, have proven so great that the use of "hard metals" promises, in some instances, to revolutionise the drilling of all manner of minerals. Early in the war years the Germans realised the tremendous advantages cemented carbides offered for holing hard rocks, and they proceeded to develop detachable percussion bits to do this work, at the same time evolving fast, comparatively light-hitting driliing machines, especially designed to suit the mechanical properties of the carbide.Here in Australia also, it has appeared that the detachable percussion bit offers the greatest economic benefits to consumers, although the author is well aware that carbide-tipped drill rods have, and may continue to work out satisfactorily in certain mines and quarries.Most drilling equipment at present installed in Australia may be described as being of the heavy hard-hitting variety, so that the designer of an efficient percussion bit has to take special precautions to overcome the problem of fatigue, and to ensure that the inserts are securely mounted in the body with the minimum of internal stress in the carbide.

Jan 1, 1950

By Tracy Brettmann

? Hollow Stem Auger ? Drill Bits ? Leads/Torque Arm ? Hydraulic Gearbox ? Hydraulic Power Unit ? Grout Pump ? Crawler Crane

Jan 1, 2001

By Robert J. F. Goodfellow, William A. T. Meakin, Kevin Clarke, Eric Cole

INTRODUCTION New York City Water Supply—Background and History Since the 1840s New York City has been developing the largest, and perhaps, the best urban water supply and distribution system in the world in terms of quality and reliability. One of the engineering marvels of the modern world, the New York City water supply and distribution system serves a population of almost nine million, including residents in nearby Westchester, Putnam, Ulster, and Orange Counties of New York State. The average daily supplies presently are running at almost 60 m3/sec(about 1,350 million gallons per day). The watershed for the New York City water supply system, under the jurisdiction of the New York City Department of Environmental Protection (NYCDEP), consists of19 reservoirs and three controlled lakes, and covers an area of approximately5,000 square kilometers (about 2,000 square miles) north of New York City. The watershed total available storage capacity is about two billion cubic meters (560 billion gallons) and is divided into three reservoir systems: the Catskill and Delaware watersheds located West of the Hudson River; and the Croton watershed, located east of the Hudson River, see Figure 1. The first element of the system, the Croton Aqueduct, started operations in 1842.Through several updates and expansions, the present-day Croton system was in place by 1911, providing a potential maximum supply of about 15 m3/s (about 340 mgd). The system includes ten reservoirs and three controlled lakes. In the late 1800s, with the tremendous growth of the City, New York City water engineers began to look for additional sources. Between 1907 and 1929, the City acquired water rights and constructed a new 148 km (92 miles) Catskill aqueduct to convey water from the Ashokan Reservoir to the City. The Catskill system also included the construction of the Kensico and Hillview Reservoirs just north of the City,

Jan 1, 2005