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By Cesar Sáenz Acosta

El presente texto señala las mediciones de impactos que se han realizado a los programas de responsabilidad social de una empresa minera. Esta medición se realizó a través del cálculo del indicador “Retorno social de la inversión”, aplicando el modelo SROIM o Gestión del Retorno Social de la Inversión. Los proyectos de RS medidos permiten actuar a las empresas de manera responsable con su comunidad y comprenden: salud y nutrición, educación y desarrollo económico. Asimismo, esta medición contribuye a mejorar la comunicación de los impactos generados y desarrolla una gestión adecuada de estos.

Sep 12, 2011

By Jerry T. Shelby

Surface and underground mining operations require equipment with high power output ratings. Haul trucks, loaders, dozers, and other equipment need increasing horse-power to meet production demands. To get more horsepower out of the engines driving the equipment, most manufacturers use turbocharging. Detroit Diesel puts the number at about 90% turbocharged, while Caterpillar estimates 75% to 80% of all its equipment is turbocharged. Turbocharging increases the power output and overall engine efficiency. But it presents some maintenance and operational problems that were not factors when only naturally aspirated engines (nonturbocharged) dominated the scene. A turbocharger is an exhaust-driven air compressor. Using the waste energy in the engine exhaust, a turbine wheel is driven. This wheel is connected by a common shaft to a compressor wheel. The shaft is supported by two plain bearings, or bushings. As the turbine wheel is rotated, the compressor wheel continually compresses the intake air to the cylinders. Compressing the intake air means that more air can be put into the cylinder to burn more fuel. The more fuel the engine can completely burn or combust, the more horsepower the engine can produce. Even though the turbocharger is a relatively simple device, it is a sensitive engine component. It requires special consideration at engine start-up and shutdown. Being freewheeling and exhaust driven, turbochargers can experience temperatures of 540°C 1000°F) and rotational speeds of more than 100,000 rpm. Due to those temperatures and speeds, lubrication is critical to the operation and life of a turbocharger. The turbo is located high on the engine, with the oil supply running through an external line from the sump. The recommended practice is to start the engine and allow it to idle for a few minutes before any revving or loading. This allows the oil to reach the turbo and properly lubricate the bearings before high rotational speeds are seen. Turbo oil supply lines can be as long as 1.5 m (5 ft). Depending on ambient temperatures and oil viscosity, it can take as long as 30 seconds for oil to reach the spinning turbo. However, as little as five seconds without oil can damage the turbo's bearings, reducing its life and overall efficiency. Lubrication problems seen at shut-down can also significantly affect turbo life and efficiency. Manufacturers recommend an idling period of five to seven minutes before engine shutdown. This allows the turbo to slow down and cool off somewhat to help prevent oil coking and bearing damage. When the engine stops, so does the oil supply. There is very little oil left on the bearing surfaces and in the turbo oil supply passages. The immediate heat transfer from the turbine wheel to shaft, bearings, and turbo body literally cooks what is left. This high heat without oil flow can cause bearing deformation by actually melting some of the bearing material. The rapid oil oxidation and coking will restrict oil passages, damage bearings and shaft. Besides heat soaking, there is another problem. If the turbo is spinning at high speeds when the engine is shutdown, the turbo must spin-down to a stop without oil flow. With the large size of turbos used on mining equipment, this spindown time without oil can be for as long as 10 to 20 seconds. Fortunately, lack of lubrication at start-up and shutdown and the subsequent bearing damage can be prevented by oil injection devices. These devices hold a reservoir of engine oil. The oil is injected to the turbocharger bearings immediately on start-up and for several minutes after shutdown. Oil injection devices are spring loaded, hydraulic accumulators. They are actuated at start-up by a solenoid wired to the starter motor. Engine oil pressure charges the accumulator during normal operation. Upon shut-down and loss of oil pressure, the device provides oil to the turbo for about two or three minutes. With an oil injection device, the engine can be started and immediately driven without fear of turbo damage. Also, an abrupt shutdown will not damage the turbocharger since the device will continue to lubricate for two or three minutes. A word of caution. Be sure the oil injection device provides positive oil displacement (pressurized oil flow). Do not use a gravity-flow device. Unless it is a true accumulator, the device could starve the turbo for oil on start-up, Ask for start-up and shut-down pressures and delivery times before considering installation. Keep the oil clean, and follow the manufacturer's recommended oil change intervals. These intervals are usually shorter than with naturally aspirated engines. Use oil with a CD rating designed for diesel applications. A multiviscosity oil is preferable. Use a synthetic engine oil, such as Mobil's Delvac 1, Gulf's Super Duty II, or Chevron's Sub-zero Fluid. Synthetics have much better flow properties at low temperatures. They also have greater oxidation stability (they can take the high heat of turbo-bearing lubrication. And they produce fewer deposits because they are more thermally stable. But synthetic oils do cost more - two or three times more. One additional point - maintain the air intake system. Since all mining is usually in a dusty environment, air filters should be changed regularly and intake systems should be checked for leaks. All intake air passes through the turbo. Any dirt or abrasives entering the turbo will damage the unit and shorten its life. While mining is a heavy duty business with severe operating conditions, you can get the life from your turbocharger that you expect by following a few simple steps: • equip the turbo with an oil-injection device to provide lubrication on start-up and shutdown; • change the oil and filters regularly; and • use the proper oil-synthetic, if possible.

Jan 3, 1987

By S. J. Schatzel, W. P. Diamond

High methane emissions originating from the active face areas and from the fractured formations overlying and underlying the mined coalbed can adversely affect both safety and productivity in underground coal mines. Since ventilation alone may not be sufficient to control the methane levels in the longwall mining environment, gob gas ventholes have become a standard supplementary methane control option in many mines. As mines progress into deeper and gassier coalbeds, or as longwall panel size increases, ventilation and gob gas ventholes together may not be sufficient to maintain methane levels within statutory limits. To decrease the risk associated with methane emissions under these circumstances, in-seam horizontal methane drainage is often used to reduce the gas content of the coalbed prior to mining. Horizontal methane drainage borehole completion designs, drilling strategies, and degasification lead times may need to be adjusted for site-specific conditions due to mine design, geology, and the gas content of the coalbed. This study investigates different horizontal methane drainage borehole patterns, borehole lengths, and degasification times prior to and during panel extraction to evaluate their effectiveness in reducing methane emissions using a "dynamic" 3D reservoir modeling of a 38 1-m wide longwall panel operating in the Pittsburgh coalbed. Results of this study showed that dual and tri-lateral boreholes are more effective in decreasing emissions and in shielding the entries compared to fewer shorter, cross-panel, horizontal boreholes parallel to the longwall face. Modeling results showed that after 12 months of pre-mining methane drainage, the average longwall face emission rates can be reduced by as much as 10.3 m3/min and 6.8 m3/min using tri- and dual-lateral boreholes, respectively. It was also shown that if pre-mining methane drainage time is short, it is important to continue methane drainage during the panel extraction to maximize reductions in longwall face emissions since additional face emission reductions achieved during this period can be comparable to pre-mining degasification.

The cyclone, or centrifugal separator, ,is firmly established in industry as a low cost separator of solids from gases.While it will also separate fluids of different densities, and solids from liquids, its main use is to remove relatively fine dusts from gases whose pr~erties are generally not greatly different from those of air. This latter phase of operation is the one that will be dealt with here.The duty of such a cyclone separating system is to take in a supply of dusty gas and separate it into its components of dust and clean gas as perfectly as possible for the least consumption of pressure head. Any separation at all causes pressure loss and, in general, the greater the separation, the greater the pressure drop needed to effect it. The percentage of dust in suspension which is separated from the gas-dust mixture is commonly called the collection or separation efficiency. Overall or "true" efficiency must take pressure drop into account and may be considered as proportional to the ratio of the percentage of dust collected to the resultant pressure drop. For any cyclone It will vary with different dusts.Many commercial adaptions of the simple cyclone are made solely on the basis of pressure drop improvement, without taking into account the effect on separation efficiency, probably because the latter is so difficult to assess correctly. It appears unfortunate but true that the majority of such adaptions and patent gadgets fitted to cyclones which decrease pressure drop, do have an adverse effect on separation. In other' words, the true efficiency is seldom increased but often diminished.Without a knowledge of what actually goes on inside a cyclone, it is impossible fully to appreciate the real effect of a modification. For instance, it is on record that a cyclone...

Jan 1, 1949

By Robert Stefanko

With passage of the Clean Streams Act of the Commonwealth of Pennsylvania and its impact on the coal industry, considerable research has been conducted to explore various approaches to the problem, including deep-well disposal. Available drillhole data from gas and oil wells were used to develop cross -sectional maps for various portions of the state and potential disposal zones were evaluated. Bethlehem Mines Corp., faced with a severe water problem at its Marianna operation in Washington County, cooperated with the Dept. of Mining at The Pennsylvania State University in establishing a 1500-ft well into the Salt Sands for the purpose of determining the feasibility of mine water disposal. The thickness, porosity, and permeability of the formation at the well site proved to be below what had been anticipated from drillhole data. Further, subsequent hydraulic fracturing did not improve the flow characteristics of the well; pumping pressures remained in the range of 1800-2000 psig for disposing of water at the rate of 150 gpm. The legal problems of disposal at the site were very formidable. When the Salt Sands proved to be less than satisfactory, permission could not be obtained to dispose in other promising formations. The paper details many of the problems associated with the experimental well and makes an assessment of the potential for deep-well disposal of mine water. The concept of disposing of liquid industrial wastes by deep-well injection is not a new one. Brines associated with crude oil long have been disposed of in this manner, with the additional benefit of aiding secondary oil recovery. More recently, with the expansion of nuclear energy, the lethal, highly radioactive wastes which are by-products of the fission process have created severe disposal problems. During the past ten years, a variety of industries have resorted to subsurface disposal, some of the details of which are given e1sewhere.l,2 The list reveals wide variations in injection rate, pumping pressure, cost, and waste disposition. Included are successful installations in Western Pennsylvania. Enactment of more restrictive clean-water legislation in Pennsylvania recently had a great impact on the coal industry. Among its provisions was the reclassifica-tion of most mine water as industrial waste whose dis-posal is prohibited in any stream of the Commonwealth. This had the effect of accelerating research in a variety of areas, although treatment methods still retained primary interest. When a feasibility study of deep-well disposal was proposed to the Pennsylvania Dept. of Mines and Mineral Industries, the Coal Research Board (CRB) approved it. This paper summarizes the efforts on this project. Acid mine water is a chemically complex liquid. having no definite quantitative relationship among its constituents. However, it is the iron disulfide (FeS2) associated with practically all coal seams that produces the objectionable products present in acid mine water when combined with air and water. The principal contaminants are sulfuric acid (H2SO,) and ferric hydroxide (Fe(OH)2. Ferric hydroxide is a rust-colored gelatinous precipitate that coats stream bottoms and destroys aquatic life. However, other ions and bacteria are present in acid mine water in varying amounts.

Jan 1, 1971

Continuing with the effort of providing new and more effective exploration methods to the mining industry, where direct methods (drilling, cross-cutting, etc.) are not applicable, either for logistical or environmental reasons or because they are costly and sometimes ineffective, we present here a new seismic technique based on full wave recording of 3-D channel waves generated within the coal seam across a longwall. In the past two years we reported the application on In-Seam High Resolution Seismic Reflection (ISHRSR) and In-Seam Seismic Tomography (ISST) to map non-coal inclusions that disrupt the coal seam continuity. In the present paper we present a 3-D In-Seam Seismic Tomography (3-DTSST) method using 3-D channel waves recorded by three component high resolution geophones. The method allows to distinguish longitudinal and transversal components of the channel waves, similar to the spheroidal and toroidal modes for the free oscillations of the earth. The recording of these waves allows a more complete analysis of the free modal vibrations of channel waves, permitting a more complete inversion of the structure of the coal seam through which they travel. The full wave analysis provides additional insights of the detailed coal structure for larger, distances than for the ones previously reported using the one dimensional method. The refinement of the inversion software is also a contribution towards the better definition of the coal seam geometry and structures disturbing them such as sandstone channels, sandstone rolls, partings, mine voids, faults, fractures, etc. The method is illustrated with three case studies where subsequent mining revealed the virtues and limitations. The first example deals with the problem of mapping mine works in one side of a longwall panel which geometry is well known, to verify its applicability to map old mine works. The second example deals with a sandstone body that partially scoured the coal seam withing a longwall panel. The third shows an application of the method to map roof conditions in a longwall panel where this problem critically affected production scheduling and costs

Jan 1, 1996

Copper ores are widespread through the Lachlan Geosyncline in New South Wales, but the size of the orebodies is generally small. The largest deposits occur in the Cobar district where an iron-rich copper ore type has been developed in Silurian sediments. Similar de- . posits to the south in the Nymagee-Mt. Hope-Melrose districts are related to quartz feldspar porphyries of probable Upper Silurian age. Deposits to the east in the Tottenham-Girilambone districts are less complex mineralogically and are possibly related to an ultra-basic source.Copper mineralization in the Highlands further to the east is often developed in Ordovician andesite or MiddleUpper Silurian acid volcanic sequences. The deposits in andesite contain considerably less galena than those in the acid extrusives; a small proportion of the mineralization in the latter has texture, mineralogy, and geologic setting analogous to the Captain's Flat copper-Iead-zinc deposit, for which both syngenetic and epigenetic origins have been proposed. Very little copper mineralization occurs within granitic material, even though rocks of this type ranging from Silurian to Carboniferous in age crop out through much of the geosyncline, and the extent of the metal contribution from plutons to the deposits in volcanics is open to question. Numerous deposits are known in the contact zone around Mid-Devonian and Mid-Carboniferous granites, however, and the formation of these orebodies has undoubtedly been influenced by plutonic activity. Small occurrences of copper with associated minor nickel sulphides are developed in a narrow serpentinite belt of possible Lower-Middle Devonian age in the southern section of the Highlands.

Jan 1, 1970

By James Goldberg, Mark Withey

The Material Service Thornton quarry is a multi-million annual production tons complex. Surrounded by busy surface highways, and divided by a railroad on the north/south axis and further divided by a major interstate highway on the east/west axis, blasting is a daily challenge. This paper deals with the problems of production blasting in an area adjacent to that interstate highway, and paralleling a busy four-lane highway. Discussion includes primary blasting issues such as borehole size, drill patterns and flyrock controls. Discussion also includes blast designs, timing schematics, smooth-wall blasting solutions, traffic and vibration concerns and many other factors influencing the success of this project.

Jan 1, 2006

By T. Rasmussen, T. G. Jørgensen, T. Fischer, R. K. McLimans, C. Knudsen, D. Frei

Ilmenite-bearing paleo-beach deposits were discovered in Jylland, Denmark using a combination of Ground Penetrating Radar (GPR), portable X-ray fluorescence (XMET), bulk XRF analyses, Computer Controlled Scanning Electron Microscopy (CCSEM), and wire line logging. The Miocene-age paleo-beach deposits are located below a thin Quaternary cover in a region of very moderate relief and essentially no outcrop demanding unique approaches in exploration. Initially, an isopach map of the Quaternary is prepared from existing water well data. A geological model for likely occurrence of Miocene paleo-beach deposits is generated and the coincidence of thin Quaternary cover and potential paleo-beach deposits define targets for detailed exploration. The defined targets are traversed with GPR to identify paleo-beach structures which are then used to define a drilling program. This methodology located a paleo-barrier island at the Vorslunde location with more than 10% ilmenite in the sand. During the drilling process, the TiO2 and heavy mineral contents of the sand were logged every meter with a portable XRF unit (XMET) and subsequently calibrated more accurately by comparison to bulk XRF and CCSEM analyses for selected samples. The bulk XRF data also provided more complete compositional information. Insitu determination of geology, heavy mineral abundance, and corroboration of the XRF logging was done using wire line logs, a combination of spectral gamma and induction conductivity logs. Detailed characteristics (abundance, grain size, shape) and chemical composition of minerals was determined by the GEUS CCSEM methodology (Frei et al, this vol.). The average weight percent TiO2 for all Ti-minerals is 62%, 60% excluding rutile. That elevated TiO2 content (>> ilmenite stoichiometric value, ca. 50 %) indicates that ilmenite experienced an iron-leaching environment. The source of the sand deposit was investigated by dating contained zircon. The results show that the likely sources of zircon are in southern Norway and southwestern Sweden with common zircon ages of ca 1100 Ma. and 1500 Ma.

Jan 1, 2005

PolyMet Mining is developing the NorthMet property near Duluth, Minnesota. Laboratory investigations had led to the development of the PLATSOL process to dissolve in one step the base metals (copper and nickel) as well as the gold and PGM’s. To complete the pre-feasibility study, a fully integrated ten-day pilot plant trial was undertaken, comprising of: high temperature (>220ºC) pressure oxidation in the presence of 5-10 g/L chloride (the PLATSOL process), followed by solid/liquid separation, gold plus PGM’s recovery from solution, conventional Cu SX/EW and recycling of the copper raffinate to the autoclave. The concentrate tested was a NorthMet bulk flotation concentrate assaying 14.7% Cu, 3.05% Ni, 0.14% Co, 26.7% S, 1.4 g/t Au, 2.2 g/t Pt and 9.9 g/t Pd. Laboratory results were fully confirmed and with minor adjustments of the laboratory PLATSOL® conditions, the following leach extractions were obtained during the pilot plant trial: Cu 99.6%, Ni 98.9%, Co 96%, Pd 94.6%, Pt 96% and Au 89.4%.

Jan 1, 2001

By H. C. Horwood

INTRODUCTION THE Argosy Gold Mines, Limited, which joined the ranks of active Ontario gold producers during the summer of 1936, holds a group of 21 claims on Casummit lake, in the Patricia portion, district of Kenora, northwestern Ontario. The Company is developing and mining goldbearing quartz veins that occur in a series of greywackes and slates of probable Keewatin age. The writer made a geological examination of the property and the surrounding area for the Ontario Department of Mines during the early part of the field season of 1936. This paper is a report on the general geology, structure, and ore deposits at the mine and is based almost entirely on data compiled during the examination. HISTORY Mineralization was first discovered on the property in May, 1929, by A. F. Hewitt, who, with J. A. Borthwick, decided that the country had prospecting possibilities and commenced work in April. Mr. Hewitt staked, and with his partner, J. Ziyone, still holds the group of claims lying immediately east of the present Argosy holdings. Mr. Borthwick staked six claims, K.R.L. 9,681 to 9,686, inclusive, adjoining Hewitt's on the west and later added claims K.R.L. 9,733 to 9,740, inclusive, to his holdings. F. Fiskness, who was also prospecting in the region, discoveted No. 1 vein on Borthwick's claims, and with his two partners, L. Parth and H. Jones, staked claims K.R.L. 9,758 to 9,763, inclusive, to the northwest of Borthwick's and Hewitt's ground. In July, 1929, the Casey Mountain Operating Syndicate, which held ground to the northwest, secured an option on Borthwick's claims. The Fiskness-Parth-Jones property was added in January, 1930, to protect the west dip of the veins. During the winter of 1930-31, the veins were explored by diamond drilling, No. 2 for a length ?of 900 feet and a vertical depth of from 51 to. 375 feet? and No. 3 .t~ a slope depth of 175 feet. I~ August, 1.931, after the msrallat10n of a miming plant, the Casey Summit Gold Mmes, limited, was incorporated to take over the property from the Syndicate. The Maple leaf Mines optioned a controlling interest in the stock in August, 1933, and on September 17th, 1934, brought a 50-ton amalgamation mill into production. From early in October to December 27th, 1934, when the mill was closed down, 4,094 tons of ore were treated to yield 887.89 ounces of gold and 87 .26 ounces of silver( ! ).

Jan 1, 1937

By K. E. Yassin, A. Yehia, M. Amar

Phosphate fines (size ≤ 45 μm), from the Red Sea Region, Egypt, were subjected to beneficiation process to recover the phosphorite grains from such fines. The sample is characterized by low P2O5 content (18.78%) associated with gangue minerals such as silica (22.77% SiO2) and carbonate (2.01% MgO) indicating its low grade. Phosphate pre-concentrate was prepared by gravity separation, using Falcon, where 63.37% of the phosphate, with 24.94% P2O5, 1.46% MgO, and 10.54% SiO2, was firstly recovered reducing the mass flow to the subsequent beneficiation process. However, the gravity tailing was the feed for the reverse phosphate flotation using bench scale column flotation where oleic acid was used as a carbonate gangue collector and amylase enzyme as a phosphate depressant. Under the appropriate flotation conditions (0.1% amylase, 5·10−4 mol/dm3 oleic acid, and temp. 30 °C), phospho-concentrate assaying 0.61% MgO, 13.14% SiO2, and 27.85% P2O5 with a P2O5 recovery of 55.45%, was finally obtained without the use of expensive depressants, e.g., phosphoric acid or sodium silicate. A tentative flow sheet for the whole process was postulated.

By H. C. George

This bulletin deals with prime movers, power-transmitting machinery, and the surface equipment and methods used to pump oil wells. It does not discuss geological problems nor the methods and equipment used in drilling or at flowing oil wells. Much of the presentation is by photographs and drawings which are described in the text. Underground equipment and methods for pumping oil wells will be discussed in a later publication of the Bureau of Mines.

Jan 1, 1925

By M. England

Test equipment has been developed to record automatically both the displacement of the pile head and the load applied during a conventional maintained load pile test. Some systems also have, in addition, been fitted with the facility for maintaining the applied load, as set by the operator, at very constant levels. The advantages are both commercial and technical, but a well trained operator has to be in attendance to control the test. Since typical test specifications in the UK require more than 19 hours to complete, it became inevitable that at least one equipment operator remained on site to expedite the test for its duration. Although electronic measurement and data logging of load tests may be more safe than previous direct observation of dial gauges. A single person remaining on a construction site alone is not to be recommended, even if they are just supervising the test. Further development of the testing system produced equipment which will perform the entire test specification as required without operator intervention. To achieve this, full automation is employed. The patented method particularly addresses the safety requirements and by using additional sensors, detects any uncharacteristic behaviour of the pile under test or of the reaction system and the equipment takes appropriate action in a controlled and safe manner. The quality of test data returned from these automated systems is a key element when analysing pile behaviour with models such as CEMSOLVE? and TIMESETTM. These analysis methods often indicate ground disturbance resulting from installation technique and have allowed pile design to be optimised using actual field data rather than theoretical considerations alone. An additional feature is remote access, this allows the data recorded to be transferred and the progress of the test to be viewed from practically any location. This permits experts to view the data 'live' and allows rapid diagnosis of any problems with the expected pile behaviour.

Jan 1, 2002

By A. Bascetin

One very important aspect of mining is deciding what material in a deposit is worth mining and processing, versus what material should be considered waste. This decision is summarized by the cut-off grade policy. The cut-off grade strategy for an open pit mine influences the annual cash flows and affects the net present value of a project. The optimization of cut-off grade strategy requires the knowledge of detailed operational costs, mining sequence, mining operation, processing, and product constraints, as well as the grade distribution of a given deposit defined by pit, phase, and different material types. Cut-off grade optimization algorithms have been developed in the past. The most common criteria used in cut-off grade optimization is to maximize the net present value (NPV). This paper describes the determination of a cut-off grade strategy based on Lane?s algorithm adding an optimization factor based on the generalized reduced gradient (GRG) algorithm to maximize the project?s NPV. The introduced algorithm is a windows based program developed at Virginia Tech that is based on a series of Visual Basic routines within a spreadsheet environment (Excel).The benefits of the methodology are demonstrated using a hypothetical case study. Keywords: Cut-off grade optimization, net present value maximization, generalized reduced gradient algorithm method.

Jan 1, 2007

Small scale' table concentration tests have many critics. Many metallurgists consider that such tests are of problematical value because of the difficulties involved in conducting and interpreting them.Many kinds of small-scale ore dressing tests are difficult to conduct, and there is, perhaps, good reason for thinking that table concentration tests are amongst the most difficuIt.Interpretation of results from small-scale tests is the responsibility of the metallurgists and engineers in charge, and it is often held that small-scale table concentration tests are particularly difficmlt to interpret.TESTING FOR TABLE CONCENTRATIONOn analysis it appears that the difficulties encountered in conducting small-scale table concentration tests are of three fairly distinct kinds. Firstly, there are difficulties due inherently to the smallscale nature of the operations; for example the smaller width of all mineral bands on the table and the less complete separation due to the shorter length of travel between the feed and discharge points.Secondly, there are the effects of batch operation owing to the fact that the mineral particles behave differently during the initial period when the sample is just beginning to spread over the table, the middle period when feed and discharge are even and continuous, and the final stage, when the last of the sample has been added and the table is beginning to empty itself.

Jan 1, 1954

By S. K. Oraee

Managers always look for systems with minimum hazards. The hazards create problems for performance of projects. The largest and most important hazards of working underground mine can be related to health, safety and environmental, because if one of these sectors be in hazard, maybe lead to close mine. Failure mode and effects analysis (FMEA) is a widely used quality improvement tool to identify the potential failure modes for measuring reliability of a product or a process. FMEA is performed by developing a risk priority number (RPN), which is the product of severity, occurrence, and detection ratings. On the other hand, with regard to uncertainty in the decision-making, fuzzy theory will be able to model this uncertainty. Fuzzy FMEA provides a tool that can work in a better way with vague concepts and without sufficient information than conventional FMEA. This article by using Fuzzy FMEA and based on HSE criteria evaluate hazards of Parvade No. 1 Mine in Tabas Coal Mine. The results demonstrate the most hazardous parameter is rock burst in this mine.

Jan 1, 2011

Open cut mining of the Black Rock chalcocite ore started in 1963. A ground movement monitoring programme was commencing in the early stages of mining when signs of instabilityof the western wall became apparent. Eventually 100.000 cu vd, of overburden Were removed beyond the rim of the western wall in an attempt to stabilize the slope. Subsequent decpenlug and mining till the final batter angle of 45 resulted in deterioration and mining was stopped 38 ft short in the ulltimte design deplh of 520 ft.Investigations showed that the geology of the western wall , was a major factor in the instability of this wall. A block jointed model was made 10 illustrate some of the pehomena observed. Quallatative agreement was found between the model deformation and the field measurements obtained.The results of the monitoring programme clearly show the value of this work In respect to the conlrol of the mining operatIon...

Jan 1, 1968

By Nathan C. Rockwood

THE title of this paper, I understand, was suggested by professional mining engineers as an opportunity for someone to pose problems rather than to offer solutions for them, but the paper will merely attempt to pose some of the production problems of the mineral aggregates industry in such manner as to create professional interest in their solution by the mining engineer, geologist, geochemist and the metallurgical engineer versed in mineral-dressing technique. DEFINITION OF MINERAL AGGREGATES "Mineral aggregates" may be defined as fragments of any rock or mineral used to supply bulk or volume or substance for a given purpose. For example, mineral aggregates are used in portland-cement concrete to provide bulk with the expenditure of the least feasible amount of cement binder. Mineral aggregates are used without portland cement or bituminous binder in highway and railway roadbeds to provide substance, to carry loads. Mineral aggregates are used in filters for water and sewage, to provide substance for the liquid to trickle through. These are only a few typical uses of mineral aggregates. For all these uses, strength, toughness, resistance to abrasion, and durability are usually prime requisites; so, while theoretically mineral aggregates may be of any mineral composition, what really is desired is a mineral composition as nearly inert under the conditions of use as anything of earthly origin can be. EXPLORATION AND POSSIBILITIES OF DEVELOPMENT The distribution of deposits of mineral aggregate is universal, since almost any part of the earth's crust can be used; even the top soil is sometimes used in stabilized surfacing for highways or airport runways. Nevertheless there is ample opportunity for exercise of the talents of the mining engineer and the geologist in finding the particular deposit that will be most economical to develop, keeping in mind such considerations as: (1) quality and mineralogical characteristics of the material; (2) size and permanency of the market; (3) final cost of opening and development of the deposit; (4) selection of location of plant; (5) methods and costs of distribution of the product in comparison with both present and possible future competition; (6) selection of the proper type of operating equipment; (7) estimation of probable waste products and their disposal. These are typical but there are other considerations also. Because profit margins are far smaller than in any comparable mining operation, it is all the more logical to assume that a higher degree of expert knowledge is desirable to make a success of a mineral-aggregates business. The industry has much engineering talent in its operating branch, but it lacks, to a considerable

Jan 1, 1943

By N. Mphathiwa

When slope angles are designed during open pit optimization, there is a risk factor applied in steepening the slopes. The steepening of slope angles has implications for the safety and economics of the mining operation. The steeper the slope angles, the greater the probability of slope failure. Although a slope failure will result in added costs, the challenge is to compile an accurate cost-benefit exercise optimizing the economic benefits of the project without exposing mine workers and equipment to unacceptable risk of rockfalls. A balance between the safety of the operation and the economics of the investment is therefore required. The ideal situation is to have a slope monitoring system that will predict slope failure by detecting any ground movement before the actual failure occurs. This early warning will allow the risk factor to be applied with a high degree of confidence, knowing that the risk will be adequately mitigated. The objective of this paper is to provide guidelines on how to design an optimal survey slope monitoring system. It is the authors? view that for a survey monitoring system to yield desirable results, it should adhere to survey principles such as working from the whole to part and consistently cross-checking. The case study used is Jwaneng Mine, and the design strategy outlined can be used as a guideline for developing a new slope monitoring system or to optimize an existing one.

Jan 1, 2014