Search Documents

By Thomas P. Meloy

Floating "fines" differs from floating "sands" because the fines have a much larger surface area compared to their mass. The forces that arise from this large specific surface the key to understanding the behavior and treatment of fine particles. Though the nature of these forces is not thoroughly understood, enough work has been done to give a qualitative picture of what is happening in a flotation cell. It is the purpose of this chapter to re-examine some of the more, recent theoretical work and-to indicate its importance.

Jan 1, 1962

By Min Chen, Nan Wang, Zhen Tian, Yingying Shen

"The enrichment behavior of phosphorus in CaO-SiO2-FeOx-P2O5 slag was studied by making an investigation on the distribution of phosphorous content in slag and 2CaO·SiO2 phase. The research results showed that the existing 2CaO·SiO2 solid particles in slag were the sites for the phosphorous enrichment. The enrichment process of phosphorus in CaO-SiO2-FeOx-P2O5 slag can be recognized as: mass transfer of phosphorus from bulk slag toward the surface of 2CaO·SiO2 particle, superficial dissolution reaction of phosphorus to 2CaO·SiO2 and diffusion of phosphorus through the product layer of 2CaO·SiO2-3CaO·P2O5 solid solution to the inner of 2CaO·SiO2 particle. Compared to the 2CaO·SiO2 particles with larger size (500µm to 1000µm), the completion time of enrichment was shorter for the particles with smaller size (less than 50µm).IntroductionDuring ironmaking and steelmaking, significant amounts of slag are produced. Contrast to the high utilization of ironmaking slag, the treatment of steelmaking slag is more difficult and challengeable, and therefore, an alternative approach is to recycle the steelmaking slag inside the ironmaking and steelmaking process itself. The main limitation to the reuse of steelmaking slag inside the process is that the refining process may be aggravated caused by the phosphorous accumulation if it is used in the blast furnace burden [1]. At the same time, the phosphorous content of steelmaking slag (approximately 1%~5% P2O5) is too low for it to be used as raw material for fertilizer [2, 3]. Moreover, owing to the diminishing supply of global iron ores with low phosphorous content, the control of phosphorus in iron and steelmaking processes has become an increasing problem, and as a result, more amounts of high phosphorus containing steelmaking slag are produced. Therefore, a valuable approach is quite appreciated in which the steelmaking slag is recycled within the ironmaking and steelmaking process and at the same time, the high phosphorus-containing phases in the steelmaking slag, suitable for use as fertilizer can be separated and recycled effectively [4]."

Jan 1, 2011

By C. R. Bopp, N. A. C. Smith

"For a period of several years, beginning with 1915, there has been a continuous change in the quality of motor gasoline. The average volatility has decreased, this to the fact that higher boiling fractions of the crude oil have been included in the gasoline. This change in quality was made necessary by the tremendous increase in the demand for motor fuel, caused by the development of the motor car, and during the war was an absolute necessity to avoid gasoline shortages. The Bureau of Mines has kept in close touch with this situation by making surveys from time to time of the gasolines sold throughout the country, as this information is of value to manufacturers and users of motor cars and also indicates when any changes are required in the Government specifications. The Bureau has just completed a gasoline survey and is in a position to make public the fact that there has been very little change in the quality of motor gasoline in recent months.During the period from January 17 to February 3, 1920, 81 samples of actor gasoline were collected by representatives of the Bureau of Mines in seven districts of the United States. The cities selected for this survey were New York, N. Y., including Brooklyn; Washington, D. C.; Pittsburgh, Pa.; Chicago, Ill.; New Orleans, La.; Salt Lake City, Utah; and San Francisco, Cal., including Berkeley. In every case the samples collected were taken in such a manner as to represent material actually being sold as motor fuel, and to include samples from each refinery marketing in the district."

Jan 1, 1920

By John C. Ferm

Although roof falls account for approximately half of the fatalities in underground coal mining, the factors that produce them are not clear. Mining methods can account for some, but in others the controlling factors are the geological setting in which the mining takes place. The present investigation was undertaken to determine the kinds of rocks that were most likely to produce roof problems. Such knowledge would be helpful to mine planning since rock samples can be obtained in advance of mining by core hole drilling. The investigation was undertaken in underground mines in the Pocahontas #3 seam in southern West Virginia and southwestern Virginia. The Pocahontas #3 is one of the most widespread in this region and is a major source of high quality metallurgical coal. There are at least ten very large mines in the area and many smaller ones. The region has a very long mining history and considerable experience has been gained in roof control problems. The study was conducted with the support of the U. S. Bureau of Mines.

Jan 1, 1978

By William F. Stowasser

The organization and operations of the information gathering system, and examples of the products prepared for the commodity phosphate rock by the Division of Nonmetallic Minerals, U.S. Bureau of Mines, are used to describe the Bureau's commodity program. Selected examples from publications about phosphate rock are used to illustrate the program. The Commodity Divisions reporting to the Office of the Assistant Director-¬Metals, Minerals and Materials, have the responsibility in the Bureau of Mines to maintain commodity records, understand the present supply and demand status of the commodity, and forecast future supply, demand, and problems. Within the Divisions, commodity specialists have the broad charter of acquiring as much information about a commodity as is necessary to characterize its history, current status, and future. This information and understanding are the base for the development of mineral policies. To accomplish these objectives, the commodity specialists acquire data and information about each commodity and produce a number of standard publications each year. In addition, as circumstances dictate, each specialist will prepare or participate in the preparation of special documents for specific purposes or problems associated with his commodity. In the preparation of reports and publi¬cations, he may communicate with industrial organizations and other Government agencies.

Jan 1, 1975

In the 1890s, The Goldfields Water Supply Department in Western Australia commissioned the diamond drilling of two deep artesian exploratory water bores near Coolgardie (Blatchford, 1899). At the time, in spite of strongly-worded advice to the contrary from the Government geologists, there was a wide popular belief that you could obtain artesian groundwater virtually anywhere providing you drilled deep enough. The first Coolgardie hole was drilled to over 900 m, despite the fact that the bore penetrated granite from a depth of 5 m below the surface. Drilling proceeded for more than 16 months, between July 1896 and November 1897. A small quantity of salt water was struck at a depth of 36 m. The second bore was mercifully terminated at a depth of 50 m, also in granite, with again only a small inflow of salt water. Such were the desperate lengths that were pursued to obtain a reliable water supply for the influx of people in the Eastern Goldfields gold rush. The WA Goldfields continued to rely on huge condensers for water supply until that great engineering feat, the construction of a water pipeline from Mundaring Weir to Coolgardie, was completed in 1903. An enormous network of rail tracks penetrated outwards from Kalgoorlie and Coolgardie for the collection of timber, principally to feed the condensers. Remnants of the rail network are still visible today. The acute shortage of fresh water led to great deprivation, disease and death among the early miners. Today, the water problems faced by the mining industry are thankfully not as severe, but they are nevertheless no less challenging. The southern part of the WA Goldfields is a notoriously difficult area for finding potable quality groundwater. Even as recently as the 1990s, there were occasional serious efforts to find potable groundwater in that area, some very imaginative and innovative. One mining company, working south of Southern Cross, spent many months experimenting with recovery of potable quality water from a shallow freshwater lens overlying hypersaline water in a low permeability weathered granite aquifer. They used very low capacity pumps manufactured from car windscreen washer pumps powered by solar panels.

Jan 1, 2000

By Guilherme L. M. G. Carvalho, Zachary T. Fleming

In a world of 2-dimensional design documents, envisioning and understanding 3-dimensional interferences for complex foundation construction scenarios can be challenging. Videos and computer models serve as 3-dimensional spatial aids but have drawbacks related to a fixed perspective. Augmented and virtual reality (AR/VR) provide new tools to communicate design challenges and improve construction planning. This paper provides a practical look at the basics of AR/VR systems and the tools available to the foundation design and construction industry by giving a high-level example of the technologies’ use in the design and delivery phases of a complex micropile installation project for the remediation of a dam foundation. Using these technologies, GEI was able to design and deliver a complex foundation remediation solution. AR/VR benefited regulators, and the client, to help understand the design concept, construction sequencing, and approach to overcoming installation challenges. Due to its user-friendly nature and less rigorous programming and hardware requirements, AR proved to be more useful than VR for this scenario. AR/VR will likely not replace videos and computer models; however, it can be a useful 3-dimensional visualization aid that complements the project delivery process and offers benefits that traditional methods cannot. INTRODUCTION Augmented and virtual reality is a promising and rapidly developing technology within the engineering and construction world. Like any rapidly developing new technology, the language describing it can be confusing and dynamic. To eliminate the confusion some definitions must be made. AR/ VR definitions The definitions of virtual reality (VR) and augmented reality (AR) for the purposes of this paper are as follows: VR is a computer-generated immersive environment that the user experiences within a digital 3- dimensional space (Satava, 1993)AR is a composite view created by superimposing digital objects into the user’s real-world view (Azuma, 1997). Often, VR is used in an office environment and allows the user to “visit” the digital site to review site planning, construction sequences, and interference geometry. AR can be utilized in both the office and onsite environments. Like VR, the in-office application for AR is commonly site planning. AR also can be utilized in the field for applications such as seeing through the ground to locate known existing obstructions like utilities, gas tanks, etc.

Jan 1, 2019

By Rayane Sonda Cassel Bielefeldt

As TRC (tensões residuais compressivas) induzidas por shot-peening (SP) podem ser relaxadas e redistribuídas sob cargas cíclicas mecânicas, térmicas e termomecânicas. O objetivo desta pesquisa é avaliar a redução da TRC por SP através da difração de raios-X fast in-situ (DRXin-situ) na superfície do aço SAE 4140 durante tempo (t) de patamar de t [s] = 54000 em três diferentes temperaturas (T) de T [K] = 423,16; 523,16 e 623,16. É investigada a relaxação de TRC por cargas térmicas, mantendo as amostras, previamente tratadas por SP, em um forno com diferentes temperaturas de patamar, enquanto são medidos os valores de TR ao longo do t. Foi construída uma câmara de vácuo acoplada a um difratômetro de raios-X. Obteve-se 100 % cobertura por SP, as TRC aliviaram com o aumento da temperatura de patamar e o tempo. A maior variação de TRC ocorreu nos primeiros minutos de ensaio, no restante do tempo a TR permaneceu constante. A macrodureza superficial e FWHM das amostras diminuíram com o aumento da temperatura de patamar ao longo do tempo. A macrodureza superficial das amostras e FWHM são maiores após o tratamento de SP, antes do aquecimento. O FWHM reduziu ao longo do tempo com mesmo comportamento da queda da TRC, correspondente e proporcional à redução da TRC. A energia de ativação do processo, calculado pela função Zener-Wert-Avrami não foi coerente com a autodifusão do Fe-a. Logo, é recomendada a repetição para verificar o resultado. Com base nos dados obtidos, se pode concluir que esta pesquisa possui relevância industrial.

Oct 30, 2017

By C. R. Austin

In a recent paper1 the authors presented information on a refinement of the Rohn type of creep test with data on pure iron that exemplified the behavior of the apparatus. The present paper extends that work to nickel and cobalt and to the examination of the comparative high-temperature properties of two widely used commercial alloys. Careful attention has been given to the effect of plastic deformation in decreasing creep rate, using the elementary metals iron, nickel and cobalt for purposes of analysis. In any endeavor to develop new materials for high-temperature service one soon encounters a real problem as to the sort of test to be employed in evaluating the commercial possibilities of the alloys. At one time it was considered satisfactory to determine the tensile strengths at elevated temperatures and to use these values as a criterion for the commercial application of the alloys. More recently the proportional limit has been used as a means of classification. Data obtained from a form of bend test have also shown promise as providing a "merit index" of high-temperature serviceability.= Koerber and Pomp3 state that since the influence of testing time is small, the high-temperature yield point of steel furnishes sufficiently reliable and concordant values up to about 350" C. (and a maximum of 450" C. for alloy steels) to serve as a suitable basis for comparison evaluations of materials and for judging permissible stresses. Koerber and Pomp consider, however, that above these temperatures creep limit must be substituted for the high-temperature yield point as the all-important characteristic of the material. Whatever may be their definition of

Jan 1, 1934

By H R. Pein

"The Corridor Sands deposit is situated approximately 190 km north east of Maputo, Mozambique adjacent to the paleo-mouth of the Limpopo River. This deposit is one of the worldÆs largest known economically viable resource of titanium, accounting for approximately one third of the global resource. As part of the pre-feasibility and feasibility study for development of the Corridor Sands project, various geological and geotechnical investigations were undertaken, selected results of which are presented in this paper. These investigations have enabled a detailed understanding of the material characteristics of the orebody as well as the tailings materials, such as the fines, to be developed. These material characteristics have had a significant impact on the selection of the mining and disposal methods currently being implemented."

Jan 1, 2001

By G. L. Fitzpatrick

Preliminary results of an experiment in seismic holography indicate that the techniques of acoustical holography may be successfully used with seismic waves to determine the size and general shape of underground objects. This experiment was carried out under field conditions on a moderately large scale compared with the typical laboratory experiments in acoustical holography. The object to be mapped was a 100-foot-diameter, spherical, low-velocity zone of explosively fractured rock in oil shale at an average depth of 80 feet. The seismic wavelength of the Fourier component wave used in making the seismic holograms was 50 feet at a frequency of 140 cps. The hologram sampling aperture was 226 feet square and was sampled by 441 geophones in a 21 by 21 rectangular array. One novel aspect of the experiment was the use of a wide-band polychromatic explosive source of seismic waves rather than a narrow-band quasi-monochromatic vibrator source. A successful laser reconstruction of the object image from a lensless Fourier-transform hologram in the form of a 5/l6-inch-square photographic transparency is illustrated. The size of the underground object measured from the laser reconstruction of the object and the size inferred from a knowledge of the amount of explosives used to fracture the site and the tensile strength of the oil shale are found to agree.

Jan 1, 1972

By A. Daouadji, P. Cazes, S. Grange, L. Briançon, R. Milane

Construction in congested urban areas is often accompanied by geotechnical problems due to high loads and the impact caused by nearby buildings. For this reason, it is important to understand the behavior of the soil and the structure without forgetting the essential role of the interaction between them. Experiments, instrumentation and numerical modeling are the main methods used to study this behavior. To this end, pressure cell, strain gages, vibrating wire extensometers and optical fiber sensors are installed on the reinforcement steel of pile and raft foundations to monitor stresses and induced deformation in these elements during and after construction. A fiberglass rod extensometer is placed in the soil to help measuring the displacement due to excess loading, knowing that the pile foundations are embedded in the Rhône’s alluviums and reach the molasse, a particular and challenging soil with properties that are not yet well understood. The objective of this paper is to present the geotechnical instrumentation program carried out for the tower Silex2 in Lyon, France, and to describe the types of sensors used and their installation on site. INTRODUCTION The complexity of geotechnical structures like dams, bridges or high-rise buildings requires a sound understanding of the behavior of the soil, the structure itself and the interface. Therefore, a geotechnical instrumentation program can be essential in many ways. During the site investigation stage, it can help determine the initial conditions experienced by the soil in the field by measuring parameters such as the compressibility index or the permeability. During the construction stage, real time measurements can protect the structure from premature failure, help validate and optimize the design if needed. In addition, sensors measuring pore-water pressure, loads, deformations and settlements allow for monitoring the performance of the structure. This is called the observational method. Finally, during the operating phase, instrumentation aims to study the long-term behavior of the structure (Nicholson et al., 1999).

Jan 1, 2019

By L. D. Woodworth, E. E. McGinley

During the past several years has occurred what, in the light of future events, may aptly be called the rebirth of the acid Bessemer process. The increased attention given to the technical and metallurgical details involved in the production of Bessemer steels has been exceedingly fruitful, and indicates the value of further research and p1ant development. In times like these, when the steelmaking capacity of the country is operating at a maximum rate to supply materials for the national defense program, it behooves the Bessemer operator not only to strive to increase production but also to maintain a high standard of quality. The opportunity is ripe, it seems, to recapture fields of application once considered the birthright of Bessemer steels, but supplanted in recent years by open-hearth grades. This involves cooperation all along the line, from the blast-furnace operator to the metallurgical contact man and salesman. The metallurgist's part in this program involves the study of the many steelmaking variables and the measures necessary to ensure constancy in the finished product. It is equally important that the knowledge gained be disseminated widely to ensure the wise application of Bessemer steels in new fields. The merits of Bessemer steels for certain work are well understood. The combined properties of good weldability, machinabil-ity and stiffness are unique and fully explain the strong entrenchment of Bessemer steels in certain fields; e.g., skelp for small butt-weld conduit, screw steels machined in automatics, and certain tin-plate applications. It is the purpose of this paper to review briefly the physical properties of Bessemer steels as contrasted with those of open-hearth steels, to discuss control measures now employed in the making of Bessemer steel, and to consider the advantages derived from the use of these control measures. Physical Properties oF Bessemer vs. Open-hearth Steels A number of Bessemer blows and open-hearth heats were tested for tensile strength, ductility and impact strength. The steels selected were confined to sections from 3/4 to 1 1/4-in. diameter, inclusive, and the carbon content covered was sufficient to yield parallel ranges in ultimate strength for the comparison. Other factors, such as the extent of deoxidation of the steel and variations in chemistry, were kept as comparable as possible. Machined test pieces of 0.505-in. diameter with an 8-in. gauge length were pulled. The data obtained are shown in Fig. I, ultimate strength being plotted against carbon content. This graph shows that for equivalent carbon content Bessemer steel has on the average 15,000 lb. per sq. in. greater tensile strength and, conversely, for the same tensile strength Bessemer steel requires on the average 0.14 per cent less carbon. The average phosphorus content for the Bessemer steel was 0.090 per cent,

Jan 1, 1941

By E. E. McGinley, L. D. Woodworth

During the past several years has occurred what, in the light of future events, may aptly be called the rebirth of the acid Bessemer process. The increased attention given to the technical and metallurgical details involved in the production of Bessemer steels has been exceedingly fruitful, and indicates the value of further research and p1ant development. In times like these, when the steelmaking capacity of the country is operating at a maximum rate to supply materials for the national defense program, it behooves the Bessemer operator not only to strive to increase production but also to maintain a high standard of quality. The opportunity is ripe, it seems, to recapture fields of application once considered the birthright of Bessemer steels, but supplanted in recent years by open-hearth grades. This involves cooperation all along the line, from the blast-furnace operator to the metallurgical contact man and salesman. The metallurgist's part in this program involves the study of the many steelmaking variables and the measures necessary to ensure constancy in the finished product. It is equally important that the knowledge gained be disseminated widely to ensure the wise application of Bessemer steels in new fields. The merits of Bessemer steels for certain work are well understood. The combined properties of good weldability, machinabil-ity and stiffness are unique and fully explain the strong entrenchment of Bessemer steels in certain fields; e.g., skelp for small butt-weld conduit, screw steels machined in automatics, and certain tin-plate applications. It is the purpose of this paper to review briefly the physical properties of Bessemer steels as contrasted with those of open-hearth steels, to discuss control measures now employed in the making of Bessemer steel, and to consider the advantages derived from the use of these control measures. Physical Properties oF Bessemer vs. Open-hearth Steels A number of Bessemer blows and open-hearth heats were tested for tensile strength, ductility and impact strength. The steels selected were confined to sections from 3/4 to 1 1/4-in. diameter, inclusive, and the carbon content covered was sufficient to yield parallel ranges in ultimate strength for the comparison. Other factors, such as the extent of deoxidation of the steel and variations in chemistry, were kept as comparable as possible. Machined test pieces of 0.505-in. diameter with an 8-in. gauge length were pulled. The data obtained are shown in Fig. I, ultimate strength being plotted against carbon content. This graph shows that for equivalent carbon content Bessemer steel has on the average 15,000 lb. per sq. in. greater tensile strength and, conversely, for the same tensile strength Bessemer steel requires on the average 0.14 per cent less carbon. The average phosphorus content for the Bessemer steel was 0.090 per cent,

Jan 1, 1941

By ARCHIBALD DOUGLAS

AT various times during the past quarter century proposals have been made that the basic Federal mining law of 1872 be repealed or amended, and that in its place a new and simpler law be enacted to provide for the entry upon, working, and the taking up of claims on the unallotted Federal mining lands in our western states and in Alaska. Serious discussion and study have been given such proposals but little has resulted there from, except perhaps a lively interchange of opinion and the conclusion that though the Apex law of 1872 is in many ways highly unsatisfactory and frequently a fomenter of strife and trouble, it still bids fair to remain with us. Under this act a greater part of the non-ferrous mining industry of the United States has developed. With all its short-comings it is the legal bridge that has carried over the innumerable caravans of adventurers and prospectors who explored our mining frontiers. For without any amendments of substance this act has for fifty-eight years been the guide in the location of our western Federal mineral claims and has stood unchanged during the most important period of our mining history. While Federal and state acts and amendments have been ground out by thousands and tens -of thousands the mining act of 1872, with a :strange tenacity, has remained as constant as the Rock of Gibraltar, and under it states, mining districts, and local customs have developed different codes for its application but its fundamentals have been unaltered. "Use doth breed a habit in a man"; until now the application of the law of 1872 has become a second mining nature.

Jan 1, 1930

1. Scope of project In South Australia, the Western Mining Corporation operates the underground copper and uranium mine Olympic Dam. The deposits concerned are enormous (approx. 570 million tons) and have been mined since 1988. At the end of 1996, Western Mining decided to increase the capacity of Olympic Dam from 85,000 t.p.a. to 200,000 t.p.a. Planning At this point, SIEMAG-GHH Mining Division was asked to carry out a study including the planning of the entire shaft hoisting operations and calculation of the investment and operating costs involved. With the assistance of Australian partners, the study was completed within a single month. The principal points of the study were as follows: ? Planning of the hoisting machinery for 1,375 tons per hour from the surge bin below ground to the discharge bunker above ground. ? Optimisation of the hoisting operation with regard to maximum availability and safety. ? Optimisation of the time schedule to minimise the financing costs of the investment. ? Statement of the investment and operating costs. ? Comparison of the technical data, design and availability of the planned machinery with reference plants. Construction of the plant Following acceptance of the study, the decision was taken within a few weeks to implement it. SIEMAG Transplan GmbH received the order to execute the entire shaft hoisting machinery on the basis of the study submitted. The decisive factors in placing the order were: ? Convincing study, adherence to schedule ? Reference to comparable plants elsewhere ? Reference with regard to availability.

May 1, 2003

The following notes have been compiled to assist authors in the preparation of papers for presentation to the Institute and for publication in the Journal. All papers must meet the standards set by the Council of the Institute, and for this purpose all papers are referred to at least two referees appointed by the Council. Although the worldwide readership of the Journal results in a preference for papers in English, the Council treats papers in Afrikaans on an equal basis, but, to meet the needs of the majority of readers, an English summary of some 5OO to 750 words should be provided.

Jan 1, 1984

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

Jan 1, 2002

By Hassell E. Hunter

The Wyoming Mineral-Conoco Crownpoint Project represents the first time that big hole drilling has been exclusively used to develop totally a privately financed mine below a depth of 1000 feet. Three shafts, one ten feet in diameter and two six feet in diameter, were successfully drilled to depths of 2243', 2188' and 2188' respectively and cased with hydrostatic designed steel casing. The largest shaft is to be used to handle muck and water from station excavation and enlargement of the other two shafts. A reverse circulation system with potassium chloride base mud was used for drilling. The mud was cleaned by settling in steel lined tanks with assistance by cyclone type separators. Deviation was monitored by gyroscopic surveying at 30 foot intervals and did not exceed 16 inches off plumb. Casing was designed to withstand hydrostatic pressures with a 1.5 safety factor to the large shaft and 1.25 safety factor for the smaller shafts. All casing welds were x-ray tested prior to lowering the casing in the hole. Cementing the annular space completed the operation. The total time to mobilize, drill and move off the three shafts was 363 days. The drilling operation was completed ahead of schedule and under budget.

Jan 1, 1983

By T. Faulkner, S. A. Richards

"Classic engineering economics provides the mining engineer with a fundamental approach to choosing between capital spending alternatives. This approach has been heavily used over the years and is an accepted technique for most investment decisions. There is a shortcoming that I have run into over the 15 year period when I worked in business planning roles. The classic time value of money approaches such as Net Present Value, Return on Investment, and Internal Rate of Return provide good estimates, but the input assumptions may fall short of describing the real material differences required by these analysis techniques. If the cost benefit analysis is defined solely on the improvement of the item being replaced or improved, the true profitability of the decision may be overestimated. Productivity improvement based capital projects can yield more accurate forecasts when conducted in concert with a “bottleneck analysis”. INTRODUCTION A review of the Theory of Constraints, (Goldratt, Cox, 1984) Lean, (Womack, 2003) (Rattner, 2006) and Six Sigma (Cryger, DeFeo 2015) lead us to recognize that these process improvement methodologies are oriented to the manufacturing process. These systems generally involve a factory that the material moves through on the way to becoming a final product. The mining challenge has many similarities to manufacturing once the ore has been won and made ready for processing. Before that point, however, the process is somewhat inverted while the ore is being won. Instead of the material moving through the factory, the factory is moving through the material. The Theory of Constraints (TOC) was used in an underground context by Baafi, Cai and Porter at 2015 APCOM, but even this groups’ analysis did not carry the concept from mining to shipping of the final product. There can be spatially distributed data that can affect the mining throughput constraints, some of which can be determined from exploration results. Identifying constraints can lead us to mapping productivity bottlenecks on future mining. Knowing this may improve decision making by eliminating one of Jim Fishbein’s three deadly sins of strategic planning: incomplete planning. When evaluating capital investment alternatives you should evaluate the impact of any proposed improvements on the entire operation. At the core of any mining system is the materials handling system. This can be typically expressed as the system that handles the raw material from the “face” through processing and then handling the finished product as well as the waste material. A “Bottleneck Analysis” is an investigation into the factors limiting a material handling system’s productivity (Goldratt, Cox, 1984). Mining material handling systems are usually composed of several linked components such as draglines, shovels, loaders, hydraulic excavators, continuous miners, longwalls, highwall miners, bucket wheel excavators, LHDs, feeders, conveyor belts, stockpiles, crushers, processing plants with various circuits, and waste handling systems. Each of the aforementioned components has a slightly different throughput capacity. When these are linked in series, the one with the lowest throughput capacity limits all of the others, creating the bottleneck for the system. Every material handling system has a bottleneck. In the mining environment, a subtle, but very significant phenomenon may also occur. The bottleneck may change as a result of a change in the raw feed qualities, face recession, overburden depth, digability, learning curve, and many others factors which may be derived from the drillhole data. These parameters often change as a function of the location in the reserve base, and may also vary with time."

Jan 1, 2016