Search Documents

By Roy A. Bell

A 200-foot diameter, 72-foot high petroleum storage tank was built in a hillside ravine where a portion of the site contained soft clay fill. Soil-cement piles, 40 inches in diameter and up to 38 feet long, were installed to support the tank shell and ringwall, and a portion of the tank floor by drilling into the stiff to hard underlying soils and weathered bedrock. The goal was to provide a strong enough foundation to resist the seismic tank shell loading and to minimize differential settlement of the tank shell to avoid out-of-round clearance problems between the shell and floating-roof. A cantilevered retaining wall up to 8 feet high was constructed around a portion of the tank perimeter by inserting steel H-beams into soil-cement piles. The cantilever soldier piles for the retaining wall were installed from a temporary earth embankment on the hillside directly over the top of the wall. The temporary embankment was then removed and the tank pad was cut to grade in front of the soldier piles. Some of the soil-cement piles for both the tank foundation and retaining wall could not be advanced to design depth because the drill/mixing tools could not penetrate to the required depth in the hard soils/bedrock. Smaller diameter borings (22 inches in diameter) were drilled through the centers of the short-of-design soil-cement piles to the design depth and then backfilled with concrete.

Jan 1, 1997

By Robert W. McKibbin

The Bureau of Mines conducted laboratory tests to determine the slurry transport and deposition properties of coal waste. A 188.5-ft pipe test loop was constructed with instruments to measure density, flow, and power and discharge, suction, and differential pressures. A 20-ton ample of Western coal waste was crushed and screened to 100 pct minus 1/2 in. Eight loop tests using this graded waste were run at slurry densities ranging from 1.15 (25 wt-pct solids) to 1.46 (60 wt-pct sol-ids) 0 The resultant friction-'pressure gradients ranged from 0,06 to 0.24 ft of water per foot of 4-in standard steel pipe. Particle-size degradation was significant.. In a typical loop test lasting 25 min, the minus 200-mesh fraction increased from 19 pct to 34 pct. Deposition tests showed that without the use of a flocculant, the slurries would not dewater when left to stand for 1 week. With flocculant, additional water was releas2d; however, the settled slurries remained thixotropic. Further testing is necessary to determine their suitability for use as backfill material in active mines.

Jan 1, 1983

By R. J. C. MacDonald

"The first recorded discovery of placer gold in Canada was on the Chaudiere River in Quebec's eastern townships in 1832 and the first major production came from placer deposits in British Columbia in 1858 (Verity 1974). Placer deposits were the major source of gold until the late 1890's, although lode deposits were found in Nova Scotia in 1862. In 1896 the Klondike Gold Rush commenced with the discovery of gold by Henderson and Carmack in the Yukon. The peak was reached in 1900 when over one million ounces of gold valued at approximately $22.3 million were recovered. With the exhaustion of the easily accessible deposits, more capital intensive operations were necessary such as those initiated in 1906 by the Yukon Gold Corporation. This giant dredging operation continued to produce until 1966. Today only a few small operations remain.The development of Canadian lode gold mining began in earnest around 1900 when the railroads were opening up the interior and western part of the country. At this time many discoveries occurred, particularly where mineral outcroppings were near surface. Tremendous impetus for exploration and the reopening of former producers followed the elimination of the gold standard by Great Britain around 1931, and more importantly the United States in 1933, with subsequent stabilization of the price of gold at $35 per ounce in 1934. Prior to this the price of gold was basically unchanged since 1717, approximately, $20 per ounce (Verity, 1974; Green, 1973).The depression of the 1930s adversely affected most industries, however for the gold producers it was a very profitable time. Prices of materials and equipment declined and labour was cheap and plentiful. Interest in gold mining was further stimulated in 1936 when a three year tax exemption was declared for all new metal mines. In 1938 a decline in the value of the Canadian dollar relative to the U.S. dollar benefitted the industry. The second world war provided yet again further incentive for gold production and in 1941 Canadian gold production reached a high of approximately 5.4 million ounces. This figure was not surpassed until 1991 when approximately 5.6 million ounces were produced (Natural Resources Canada, 1996 )."

Jan 1, 1998

Power Plant. The power for the metallurgical operations is supplied by the company's own power plant, which is centrally situated. Power is also supplied to Metal Manufactures Ltd. and Australian Fertilizers Ltd., both being adjacently situated to this company'sworks.The power supplied is direct current, 250 volts, and is obtained from direct-current generators coupled to turbines and to Belliss & Morcom triple expansion engines.The steam supply is obtained from Babcock & Wilcox water tubular boilers, the fuel used being drawn from the South Coast coal mines.Transport. - The works are connected by standard broad gauge railway to both the jetties and the Government railway. Two steam and three electric locomotives are employed in this service.In addition to its own requirements, transport is provided to Metal Manufactures Ltd. and Australian Fertilizers Ltd.The various operating departments are connected by a 2-ft. gauge railway operated by Jeffrey electric locomotives.Ore Storage and Sample Mill - These departments are connected by broad gauge line to the Government railway and jetties. All material which is railed or shipped to the works from the various centres is weighed, sampled and placed in the ore store, or outside gantries, before being treated.Since the whole of the material received is either purchased or treated on a toll charge, great care is necessary in the weighing and sampling of all the receipts.Assay Oflice--The assay office is divided into several laboratories, where analyses of the various purchased materials and works samples are carried out.

Jan 1, 1938

By N. R. Morrow, C. C. Harris

The experimental points which describe capillary pressure curves are determined at apparent equilibria which are observed after bydrodynamic flow has ceased. For most systems, the time required to obtain equalization of pressure throughout the discontinuous part of a phase is prohibitive. To permit experimental points to be described as equilibria, a model of capillary behavior is proposed where mass transfer is restricted to bulk fluid flow. Model capillary pressure curves follow if the path described by such points is independent of the rate at which the saturation was changed to attain a capillary pressure point. Aemodified suction potential technique is used to study cyclic relationships between capillary pressure and moisture content for a porous mass. The time taken to complete an experiment was greatly reduced by using small samples. INTRODUCTION Capillary retention of liquid by porous materials has been investigated in the fields of hydrology,l soil science,2 oil reservoir engineering,3 chemical engineering," soil mechanics,5 textiles: paper making: and building materials In studies of the immiscible displacement of one fluid by another within a porous bed, drainage columnsl and suction potential techniques2 have been used to obtain relationships between pressure deficiency and saturation (Fig. 1). Except where there is no hysteresis of contact angle and the solid is of simple geometry, such as a tube of uniform cross section, there is hysteresis in the relationship between capillary pressure and saturation.2 The relationship which has received most attention is displacement of fluid from an initially saturated bed (Fig. 1, Curve R2), the final condition being an irreducible minimum fluid saturation Swr. Imbibition (Fig. 1, Curve A), further desaturation (Fig. 1, Curve R), and intermediate scanning curves have been studied to a lesser but increasing extent.2 ,3,9-12 This paper first considers the nature of the experimental points tracing the capillary pressure curves with respect to the modes and rates of mass transfer which are operative during the course of measurement. There are clear indications that the experimental points which describe these curves are obtained at apparent equilibria which are observed when viscous fluid flow has ceased; and any further changes in the fluid distribution are the result of much slower mass transfer processes, such as diffusion. Unless stated otherwise, this discussion applies to a stable packing of equal, smooth, hydrophilic spheres supported by a suction plate5 with water as the wetting phase and air as the nonwetting phase. The discussion can also be applied, in many

Jan 1, 1966

By Verya Nasri

The proposed Second Avenue Subway Project in New York City is approximately 8.5 miles long, up to a depth of 120 feet beneath grade and runs the length of the eastern side of the island of Manhattan from Harlem in the north to the financial district in the south. It will reduce overcrowding and delays on the existing parallel line, improving travel for both city and suburban commuters, and upgrading access to mass transit for residents of the East Side of Manhattan. This subway line will have 16 new stations providing transfers to the existing Metro-North commuter rail service and to New York City Transit subway lines and bus services. The first phase of construction includes two TBM rock tunnels 2.4 miles long and two new large and shallow rock cavern stations with clear span openings ranging from 70 to 100 feet and length in excess of 1000 feet with 615 feet center platform, coupled with low rock cover ranging from 20 feet to 40 feet. The design methodology for these large and shallow rock caverns consists of using well known empirical methods for initial estimate of support requirements and then two and three dimensional continuum and discontinuum analyses for verification of the selected excavation sequence and support system. This paper describes the analysis and design methodologies used for the two large and shallow rock caverns with insight into how to overcome the design complexities and construction challenges of the urban underground.

Jan 1, 2008

By Frank B. Fulkerson

A study was made of scrap iron and steel in the South Central States in order to determine trends in processing, shipment, and consumption of this important commodity. These data were derived in part from statistical sources and in part by visits to scrap yards and steel mills. Trends in the industry were reviewed. Dealers in 1963 supplied 1.8 million tons of iron and steel scrap to steel mills and foundries in the south-central area, compared with 2.1 million tons in 1955. Most of the scrap was processed and shipped within 200 to 300 miles of consuming centers. Exports provide a principal outlet for dealers along the gulf coast. Most of the scrap that fills these orders is loaded onto freight cars at yards in Texas and Louisiana and -is shipped to ports for direct transfer from railroad car to ship. The tonnage exported varies greatly from year to year. The largest scrap operations are in or near large cities which are heavy scrap generating areas, steel mill sites, or port cities for export of scrap. A tentative analysis indicates that the short-run supply of prepared scrap is inelastic to price changes; therefore, buyers probably arc in a strong bargaining position at times of declining demand. One technological development in the iron and steel scrap industry is the use of large presses which can take complete automobiles with frames, wheels, springs, and other heavy parts still intact and reduce them to bundles. At Houston, Tex., and Kansas City, Mo., shredding plants are in operation that reduce car bodies and other light scrap into flat pieces 4 to 6 inches in size.

Jan 1, 1966

By J L. Carpenter, S M. Iveson, K P. Galvin

Wet beneficiation of iron ore fines less than 1 mm typically involves a desliming stage ahead of the fine gravity separation such as spirals. The desliming is achieved using a bank of cyclones. The reject ultra-fines emerge in the overflow stream at relatively low pulp density, contain high proportions of low-value slimes, but also well-liberated iron ore ultra-fines below 0.045 mm in size; however, recovering the valuable iron ore ultra-fines from this overflow stream presents a significant challenge due to the need to remove such a large amount of water and slimes.The REFLUX™ Graviton consists of distinct 3D-printed modular units, based on REFLUX™ Classifiers, which are rotated at high speed in a large centrifuge. This system has previously been investigated under semi-batch conditions, demonstrating the potential for precision separations with significant capacity. It has been shown that the throughput advantage of the inclined channels and G forces multiply. This is the first paper presented showing the performance of this system under continuous steady-state conditions. Ultra-fine silica in the size range of 0 to 0.045 mm was fed to the Graviton at different volumetric rates, fluidisation rates and pulp densities ranging from 2 wt per cent to 30 wt per cent, in order to develop a fundamental understanding of the system’s performance. Experiments were then repeated using ultra-fine iron ore.CITATION:Carpenter, J L, Iveson, S M and Galvin, K P, 2017. Separation of ultra-fine particles using the REFLUX™ Graviton, in Proceedings Iron Ore 2017, pp 141–148 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 24, 2017

When defining a ?megaproject,? one need only to look at Seattle, WA?s State Route 99 Alaskan Way Viaduct replacement project. This $3.1-billion project is one of the largest of its kind in the world, and includes the use of the world?s largest tunnel boring machine (TBM). However, for as large as the Alaskan Way project is ? especially given the size of the TBM being used ? there are several other megaprojects underway around the world. Each has its own challenges that require innovative design techniques and financing arrangements, as well as variations on established tunneling technologies. So it was that 266 tunneling and underground construction professionals ? owners, contractors and engineers ? convened in Seattle in November for the Cutting Edge Conference on Megaprojects. This was the second joint meeting between the Underground Construction Association of SME and the North American Tunneling Journal. The first joint conference took place in April 2012 in Miami, FL and attracted 238 attendees. A third joint conference, to be held in 2014, is in the planning stage. The key reason Seattle was chosen as the site of the megaprojects conference is the Alaskan Way Viaduct project. Before the conference began, many of the attendees were able to visit the project and get a close look at Bertha, the Hitachi Zosen earth pressure balance TBM that is boring the tunnel. In addition, the conference included an exhibit that attracted 20 industry suppliers, up from 10 the previous year in Miami. The 25 presentations during the two-day conference covered all aspects of the tunneling and underground construction of megaprojects. Topics included the Alaskan Way Viaduct project; considerations for procurement and contracting; political risk, financing and insurance; international megaprojects; risk and risk sharing and project delivery. Each session concluded with panel discussions.

Dec 1, 2013

By F. A. Camisani-Calzolari

The latter half of the 20th century has seen the proliferation of a series of codes to address commodity needs which were brought about by rapidly advancing technologies and the globalization of markets and consumerism. This paper addresses the specific needs and the origin of this surge and presents these codes in the context in which they were developed. It also compares the main codes or groups of codes and elaborates upon their strengths and weaknesses. Three main categories of codes are identified, namely codes for reporting to international agencies, codes addressing government needs and, finally, codes for the investors and the stock market. Codes governed by international agencies usually relate to strategic commodities which have highly specialized fields of usage such as nuclear power generation where international cooperationis eventually the only viable approach for both the development of technologies and their applications. Codes for reporting to governments address the necessity of each state to exploit its mineral potential profitably and to secure the preservation of wealth for future generations. Reporting to investors is experiencing a considerable popularity as of late because of globalization in mining and the growing need for outside financing of mining projects, whose capital requirements are getting out of reach for the average mid-cap mining company. All these codes have advantages and shortcomings dictated by the specific circumstances under which they were developed, therefore necessitating the definition and implementation of some kind of international standard whereby investments and the spread of information across political boundaries would be facilitated. Though none of these codes might ever become international in the true sense of the word because of significantly different legislations at national level, a step that would greatly contribute to the cross-border disclosure of information would be the reciprocal recognition of competent persons by the major mining countries, including China and Russia. It is also becoming essential that financial institutions and investors be properly advised on mining projects by reporting reserves and resources in a transparent and responsible way with the relevant public disclosures being compiled by professionals who take full responsibility for their submissions. Keywords: reporting codes, mineral resources, mineral reserves, competent person, UN Framework Classification, IAEA classification, JORC Code, SAMREC Code and CRIRSCO.

Jan 1, 2004

By C. Schuffeneger

"The design of SAG milling circuits for mining projects requires the incorporation of the energy consumption considerations and the evaluation between different flexibility-adding options to absorb the time-dependent variation in the ore lithology. In order to expand the focus of the engineering design, a higher level of deepness and quality in the baseline information must be achieved to elucidate all of the constraints on throughput, energy consumption and product quality generating a design optimization consistent with an integrated vision of the process. This paper presents a review of a collection of typical examples of the copper and gold mining project in the Chilean Andes, in which both process and energy efficiency criteria are considered when the focus is to deliver an integral solution that incorporate those areas in the design. The intensive use of energy in the SAG milling, the process continuity and the quality of the product are a function of the proper design and selection of grinding equipment and plant layout, aligned with the mining plan and associated with projected future expansions and production increases.INTRODUCTION Autogenous and Semiautogenous grinding technology, large diameter and short length mills, begins with the Handsel design. During the decade of 1930’s, Handsel-Hardinge studies led to cascade mill development. Nowadays, 80 years later, continuous improvements in design and technology have been conducted to a completely new generation of gearless SAG mills that have led to an increasing capacity at the concentrator plants. Considering the existing alternatives, SAG mills are the most implemented option for the grinding circuit today. This work presents a review of the SAG mill implementation parameters and circuit considerations and its correlations in the most recent projects in Chile with an ore treatment capacity above 50 ktpd since the decade of the 90’s up to now. From this period, the tendencies will be analyzed using project design data. Based on process design information, the recent SAG mill history in relevant projects related to the new generation of commercial SAG mills, technical associated considerations and performance will be discussed. Circuit selection based on energy utilization will be revised to bring up a more holistic perspective on the SAG mill circuit design concepts. As is now well known, the heart of every concentrator plant are the grinding mills. Higher demands on throughput, availability and power consumption optimizations require not only high performance electrical equipment but also a well selected grinding circuit. The energy efficiency issues associated to the circuits design will be reviewed."

Jan 1, 2012

By Y. Özçelik

Rocks show a variety of engineering and physical properties that affect typical quarry operation such as diamond wire cutting in the marble quarry. The physical and mechanical properties of rocks depend on their mineralogical and petrographical characteristics. The purpose of this study is to investigate the effects of mineralogical and petrographical properties of a rock, such as grain size and mineral content, and how these affect the wearing of diamond bead and cutting rate in a diamond wire cutting operation in a marble quarry. Statistical analysis is used to carry out the study. Three different rock types were examined, namely, hard rock (andesite) and softer rocks like limestone and marble. The study revealed that the mineralogical and petrographical properties of the rocks, such as percentage of quartz, biotite, plagioclase, matrix minerals, and opaque minerals, are important. In addition, the grain size of quartz and plagioclase in andesitic rocks and calcite grain size for carbonate rocks significantly influenced the wear rate and cutting rate in diamond wire cutting operations.

Jan 1, 2005

By Paul C. Schmall

The link between artificial ground freezing and the mining industry stretches back more than 140 years, and across an ocean. Patented by the German scientist F.H. Poetsch in 1863, the technique is reported to have first been used circa 1862 in the coal mining valleys of South Wales. In the United States, the first ground freezing application, to a depth of 30 m (100 ft), occurred in 1888 for the Chapin Mine Co. in Iron Mountain, MO. In England in 1901, the Poetsch method was used for the first time to successfully sink two shafts through 24 to 27 m (80 to 90 ft) of wet sand and boulder clay at the Washington Glebe Colliery, near Sunderland. British mining engineer T.H. Cockin, in his 1905 Class-Book of Practical Coal-Mining, noted that, ?This method of sinking through thick beds of very wet quicksand has met with great success; it is one of the recognized methods of sinking on the Continent.? Mine shaft freezing soon became relatively common in Europe where the project could bear the cost of a major refrigeration plant construction. However, it was not until 1952 that the second North American ground freezing project was completed to facilitate the sinking of a 4.5-m- (15-ft-) diameter, 233-m- (765-ft-) deep shaft at a Potash Company of America (PCA) mine in Carlsbad, NM. Nowadays, ground freezing is used worldwide for both mining and civil applications. In small mine shafts of 3 to 6 m (10 to 20 ft) in diameter, excavations have been carried out to depths of more than 820 m (2,700 ft) within the protection of unbraced or unlined frozen walls. In fact, for deep mines, no better method has yet been established for sinking production shafts through deep, water-bearing ground. Major deposits of coal, potash and salt would still be inaccessible if not for artificial ground freezing. There are several advantages of ground freezing unique to the construction of shafts. Proper instrumentation can provide complete assurance of the integrity of the freeze to full depth prior to excavation. The frozen wall allows construction to be scheduled without evaluating the in-shaft time necessary to probe ahead, place additional sup-ports or deal with ground water. The freeze can be implemented perfectly through the soil/rock interface, which is often the most difficult geology in which to create a ground water cutoff by other methods. At increasing depths, any discontinuity

Jan 1, 2007

By M P. Simpson, J L. Mauk

The Golden Cross, low-sulfidation, epithermal deposit shows a number of features that are directly or indirectly related to boiling hydrothermal fluids. Occurrences of lattice calcite and their quartz pseudomorph equivalents in veins, and occurrences of adularia in veins and in the surrounding altered rocks in the vicinity of ore, are both direct evidence of deposition in the presence of boiling hydrothermal fluids. Loss of carbon dioxide causes calcite deposition (platy variety) near the level of first boiling, while adularia deposits due to the attendant pH increase along the cooling flow path. Indirect evidence of boiling include crustiform-colloform quartz banding, late massive calcite veins, clay-carbonate alteration in the shallow and peripheral parts of the ore zone, and the restricted vertical interval of precious metal mineralisation. The colloform quartz banding strongly resembles the banding in amorphous silica deposits found in geothermal surface pipes. This implies that fluids ascending the Empire Vein structure were saturated in amorphous silica. If so, then they must have undergone phase separation, which initiated at considerable depth (e.g. =1000 m) and very hot temperatures (e.g. =300¦C). On the basis of stable isotope data, late massive calcite veins appear to have deposited from CO2-rich steam-heated waters. Calcite deposited along heating paths as these waters descended into the upflow zone during late stage collapse of the hydrothermal plume. In active systems, such steam heated waters form by deep boiling. The high CO2 contents of these waters promote hydrolytic alteration and the formation of clay-carbonate alteration. Reaction path modelling using CHILLER and a deep, Broadlands-Ohaaki water as an analogue, shows that minerals deposit along boiling flow paths over discrete spatial intervals. Calcite and adularia deposit near the site of first boiling, followed by gold and then by amorphous silica. For deep boiling starting at 300¦C, these minerals deposit over a path length that exceeds 1000 m. The distribution of banded quartz and gold at Golden Cross are consistent with such a boiling model. However, the elevation of first boiling must have fluctuated over 500 m to account for the coincidence of lattice quartz (pseudomorphs of platy calcite) and adularia, crustiform-colloform silica and gold over distances of a few centimeters in veins. We deduce that a downward propagating boiling front and expansion of two-phase flashing in a flowing water column occurred during episodes of high vertical permeability and fluid flux in the Empire vein structure.

Jan 1, 2000

By J A. Rabe, PAP Fouche, K O?Neill

Two of the most important issues mines have to deal with are tracking the ore mined from pit to plant and to test the efficiency of beneficiation equipment. Kumba Resources and Saco Systems are working together at moment to develop a RFID tracer system to help address these issues. This paper will focus on the tracking of ore from pit to plant. The main advantages for ore tracking is to ensure plant feed blending and dilution according to plan. The RFID tracer system works on the basis of a tracer that physically simulates the ore properties and radio frequency technology that facilitates communication with the tracer and allowing information to be stored on the tracer. This paper tends to indicate the progress on the application of RFID tracer technology in the minerals processing environment as tested at Kumba Resources so far. It is concluded that the system has great potential, but some important problems remain

Jan 1, 2005

By M. Kahn

This paper traces the rise of South Africa's mining industry in the context of the different state forms that oversaw its development. It commences with the mining-led industrial revolution through four periods of conflict, each of which contributed to a deepening of the industrial base, with constant battles between domestic and foreign capital and labour, and the rise of both Afrikaner and African nationalism. The role of state-owned enterprises has been crucial in shaping this dynamic so that at its peak the public sector and leading mining houses constituted two massive centres of power. This was followed by a thirty-year period of neo-liberal experimentation. The current debate on the 'developmental state' is an attempt to reconstruct the state as a counterweight to capital. It is argued that while the country has moved toward inclusive political and economic institutions, these are both limited by deep 'extractive' characteristics. This transformation failure provides a fertile ground for populism that presents one of the biggest threats to inclusive growth. Cited examples point to the many ways that states have sought to deal with the bonanza that conversion of mineral non-resources into resources brings. Such greenfield resources on state land, or in areas where the state holds monopoly rights, do not present ownership issues. It is suggested that this is the route that South Africa should follow, as the alternative will be conflictual.

Jan 1, 2013

This paper contains an account of some creep tests on electrolytic lead and some of its alloys. The stresses used in determining creep were 500, 350, and 200 lb. per sq.' in. The alloys contained silver, bismuth, tellurium, antimony and zinc respectively. All were castin vacuo, and tested "as rolled." Tests were done also on electrolytic lead which had been cast in air.The electrolytic lead contained 0.0005% total impurities.The preparation and vacuum casting of this lead have been described in a previous paper in this series. The preparation of the alloys, and the air casting of the electrolytic lead, are described in the next section.EXPERIMENTAL PROCEDURE.Every effort was made to keep the vacuum-cast specimens from contact with the atmosphere throughout their history.The ingots were stored eIther in a vacuum desiccator or immersed in heavy oil. The creep specimens were coated with vaseline except during rolling, etching and photography, which involved exposure to the atmosphere for about 45 minutes all told.It is not claimed that vaseline is a perfect shield against the intrusion of atmospheric gases. Possibly during the months that some tests were in progress the gases diffused through the vaseline and gained a limited access to the lead.Nevertheless, the use of vaseline gave protection that brought the tests nearer the ideal at which the author aimed, *Research Fellow, Dept. of Metallurgy, University of Melbourne.

Jan 1, 1936

By Miguel Pimentel

El presente trabajo describe el proceso implementado por la minera Yanacocha para el tratamiento de las aguas de exceso a través de la Tecnología de Membranas (EMS- Engineered Membranes System) o proceso de Osmosis Inversa, conocida también por las siglas en inglés de RO (Reverse Osmosis). El proceso RO tiene por objetivo tratar la solución barren proveniente de la planta de Merrill-Crowe para reducir el contenido de cianuro, así como los metales disueltos y otras sustancias como nitratos y nitritos en la solución.También, busca clarificar el agua tratada para cumplir con las exigencias que establece el Ministerio de Energía y Minas (MEM) y el Banco Mundial (IFC) en cuanto a límites de descarga permisibles. Una vez alcanzados los niveles establecidos, y con la aprobación del área interna de Control de Calidad, el agua tratada se descarga al medio ambiente.

Sep 12, 2005

Virtual Reality (VR) simulations are excellent tools for training, education, simulation of abnormal and dangerous conditions in mines and solving complex problems. Although the concept of VR has been around for nearly half a century, it has taken recent advances in hardware and software to bring this technology to within the budgetary reach of ordinary users and researchers. VR is now successfully being used in the minerals industry for: data visualization, accident reconstructions, simulation applications, risk analysis, hazard awareness and training. The Institute of Sustainable Minerals Industry, Advanced Computer Graphics and Virtual Reality Research Group (SMI-VR) at the University of Queensland, established in late 2000, has been involved in developing VR applications for the minerals industry in conjunction with various research centres. This paper illustrates the benefits of using advanced computer graphics and VR techniques in the minerals industry with some examples of applications developed.

Jan 1, 2003

By A. D. Mukherjee, H. N. Bhattacharya

Middle Proterozoic sulphide ore mineralisation occurs in isolated blocks of the NE-SW trending Delhi fold belt composed of Delhi Supergroup rocks. The Ajari-Basantgarh-Pipela belt forms part of the longest, widest and westernmost tectonic unit of the Delhi fold belt and consists of amphibolites, metapelites, quartzites and carbonates. The metapelite lenses and associated amphibolites host pyritic copper mineralisation. Mineralisation takes the form of sheet-like bodies consisting of ore lenses of various sizes interlayered with host or associated rocks. Massive, banded and disseminated varieties of ore are found. Pyrite is dominant with subordinate chalcopyrite and sphalerite. Pyrrhotite, galena, cubanite, mackinawite, marcasite and freibergite constitute the minor minerals. The characteristic features of the ores suggest a possible correlation with Besshi-type deposits, and the closely associated amphibolites are interpreted as low-K tholeiites of a fore-arc setting

Jun 19, 1905