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One of the critical challenges facing the mining industry ? and not just in the United States ? is the looming labor shortage. A significant percentage of the industry?s professional workforce is, well, getting old, and many will be retiring in the next 10 years or so. This is not a new issue to the industry. It has been discussed at various industry meetings and conferences for many years. How does mining, with its largely negative public image, attract young people to mining schools? And, equally important, who is going to teach them? Mining schools, what?s left of them in the United States, are beginning to lose qualified faculty to retirements, and no one is available to replace them. SME addressed this issue during the keynote session at its annual meeting in February in Denver, CO. This year?s theme was ?Mining: It?s About the People.? Despite a blizzard that blanketed the city on the day most attendees were to have arrived, the meeting still attracted a record 7,202 people. And the accompanying exhibit sold 822 booths, also a record. The U.S. Department of Energy?s National Energy Technology Laboratory contracted with the National Academies? National Research Council to complete a study concerning the availability of skilled workers to meet the energy and mineral security requirements for the United States. The National Research Council, in turn, asked SME to collect and analyze workforce trends in these industries. The result of SME?s analysis is the report ?Emerging Workforce Trends in the U.S. Energy and Minerals Industries.? It is available on the SME website, www.smenet.org. Click on Government Affairs. While the report did not paint a completely dismal picture, there were some disturbing results. It concluded that within 20 years there will not be a sufficient number of skilled professionals to satisfy the labor demand. That said, the report said that most of those positions would likely be filled. However, the U.S. mining will go through a period of time when the workforce will be made up of very young and senior workers.

Jun 1, 2013

By King K. Mak

The objectives of this study are to: (1) Assess current signing regulations and practices; (2) Develop effective signing guidelines; and (3) Evaluate the applicability and appropriateness of the proposed signing guidelines through field demonstration at representative mines. A literature search was conducted to determine the state of the art for signing applicable to surface mine haulage roads as well as survey of existing MHSA regulations and review of MSHA accident records. Nine representative mines were visited to gather information on current signing practices. Preliminary signing guidelines were then developed based on the abovementioned data. Field demonstration of the preliminary signing guidelines was conducted in which signing programs were implemented in two selected mines. Signing requirements were first assessed at each of the two participating mines. Subsequently, the necessary signs were designed, purchased, and installed at the two mines. Evaluation of the signing program as to its adequacy, appropriateness, and effectiveness was solicited from both mine management and operations personnel. Experiences gained from field evaluation were then incorporated into the final signing guidelines as presented in this final report.

Jan 1, 1981

Recommendations from 44 mining industry workshops are summarized and reviewed in the context of Bureau of Mines research and development programs on-going during the period 1974-1977. Approximately 1,000 specific recommendations for research and development are summarized in a systematic and comprehensive format appropriate for review by mining research and development program managers. Relevant Bureau of Mines research programs are briefly described and some opportunities for future research and development are identified.

Jan 1, 1979

By R. W. Brock

This subject is too broad and comprehensive to be dealt with adequately and authoritatively in this paper. It calls for the knowledge and experience of many men, but the results from such collaborative effort would be of great value, particularly if similar reports of the principal mining districts of the world were made on a standardized basis so that conditions everywhere might be directly and accurately compared. In considering conditions affecting mining in British Columbia, unfavourable as well as favourable factors must be taken into account. The unfavourable are apt to loom large and to be exaggerated rather than minimized; for it is human nature to see the blackness of the cloud rather than the silver lining; to think that one's own undertaking is beset with peculiar difficulties, and to attribute lack of greater success to out-side causes rather than to personal shortcomings. It should be recognized, however, that there is no country where the conditions for mining are ideal. The ideal mining country is the product of imagination, invested with every favourable condition found anywhere, but with none of the unfavourable conditions that are always present in reality. So if British Columbia has some handicaps to the industry, it is in good company. What is important is that the advantages compensate for the disadvantages, that the balance will compare favorably with that of competing states, for mining, like every other industry is competitive, and the cost of one's product must have a definite relationship to its price in the world's market.

Jan 1, 1924

By G Lane, M Bueno

In a recent publication (Bueno and Lane, 2011) the authors presented the analysis of a consolidated dataset composed by 137 autogenous/semi-autogenous grinding (AG/SAG) mill pilot trials. By comparing the measured data against theoretical specific energy consumption, the analysis indicated which circuit configurations were more or less energy efficient. However, the analysis has also indicated that the energy efficiency of each of the types of circuits vary significantly.There are numerous factors that contribute to the variations of energy efficiency of AG/SAG mill-based circuits, such as feed size distribution, recycle ratios and ore characteristics. In view of this, the present work accesses these factors individually and discusses what may lead a particular circuit configuration to be more or less efficient in terms of energy and costs.CITATION:Bueno, M and Lane, G, 2012. Key drivers of energy and cost efficiency in autogenous/semi-autogenous grinding circuits, in Proceedings 11th AusIMM Mill OperatorsÆ Conference, pp 113-118 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Oct 29, 2012

By John W. Adams

The present status of the National Bureau of Standards program is that many magnetic tapes of analog data have been recorded in four major mines. Each mine uses different types of equipment. In addition, some surface measurements of noise have been made at two additional mines. Two types of recordings have been made: (1) broadband measurements for spectral plots and (2) narrowband measurements for amplitude probability density (APD) plots. Only data from one mine (Robena #4) has been processed and was, presented at this workshop. The short-term goals are: (1) finish processing data from the other mines, (2) establish or reduce measurement system uncertainties, (3) put Robella report into final form for distribution, and (4) hold a review to determine what has been done, to distribute and to interpret the preliminary data, and to determine what still needs to be done. Long-term goals are: (1) complete final reports on each of the mine trips, (2) establish techniques for predicting noise in mines already visited and establish uncertainty bounds for these predictions, and (3) establish techniques for predicting noise in mines that have not been visited (but that use similar equipment to those visited) and also establish uncertainty bounds for these predictions. Specific factors or formats to be presented include: (A) For underground broadband measurements: 1. 300 Hz to 100 kHz spectral plots 2. 300 Hz to 384 kHz spectral plots 3. 300 Hz to 192 kHz spectral plots 4. 300 Hz to 6kHz (subject to change to 3 or 12 kHz) spectral plots (B) For surface broadband measurements: 1. 300 Hz to 6 kHz (or 12 kHz) spectral plots 2. 300 Hz to 3 kHz spectral plots (C) For underground narrowband measurements : 1. APD plots at 12 frequencies from 10 kHz to 32 mHz of magnetic field strength 2. R. M.S. and average values will be calculated based on time averaging for these plots (D) Sample spectral measurements of: 1. Roof-bolt voltages 2. Trolley wire-to-rail voltages 3. Phone line currents

Jan 1, 1973

By J. C. Platt

I DESIRE to call the attention of the Institute to what is believed to be a new improvement in 'the construction of journal-bearings, having for its object the reduction of original cost as well as cost of renewals. In an ordinary railroad car we find the space between the top of the axle and the top of the box is filled with a "brass," weighing from seven to ten pounds. Of this amount of metal a comparatively small portion is subjected to the wear which it is intended to meet. The balance is, practically, a filling material, which from habit has long been constructed of the same metal. The Defreest bearing is made of three parts, namely, a malleableiron back, a bronze bearing-piece, and between them a filling-piece of sheet lead. The bronze takes the wear of the axle, the iron fills up the space and acts as a backing to the bronze, and the lead, being soft, adapts itself to the inequalities in the surfaces of the iron and bronze castings, thus insuring a uniform bearing on all points, and making it unnecessary to bore out the iron or turn off the bronze to bring them to a perfect contact at all points. These three parts are joined together by two soft brass rivets, with counter-sunk heads, to prevent separation in handling. A groove is cast in the iron, and a corresponding rib on the bronze, to prevent the latter from turning with the axle when in place. In renewals it is ordinarily necessary simply to drive out the rivets and renew the bronze and lead. The iron part is not subjected to much wear and should last for years. It is evident that the first cost of these journals, and also the cost of renewals, must be much less than the old form. This difference amounts, at the present price of materials, to $9.60 for an eight¬wheel car, in first cost, and $4.72 for renewals. These bearings have been in use, and found to do what is claimed for them.

Jan 1, 1880

By J. C. Platt

1 desire to call the attention of the Institute to what is believed to be a new improvement in 'the construction of journal-bearings, having for its object the reduction of original cost as well as cost of renewals. In an ordinary railroad car we find the space between the top of the axle and the top of the box is filled with a "brass," weighing from seven to ten pounds. Of this amount of metal a comparatively small portion is subjected to the wear which it is intended to meet. The balance is, practically, a filling material, which from habit has long been constructed of the same metal. The Defreest bearing is made of three parts, namely, a malleableiron back, a bronze bearing-piece, and between them a filling-piece of sheet lead. The bronze takes the wear of the axle, the iron fills up the space and acts as a backing to the bronze, and the lead, being soft, adapts itself to the inequalities in the surfaces of the iron and bronze castings, thus insuring a uniform bearing on all points, and making it unnecessary to bore out the iron or turn off the bronze to bring them to a perfect contact at all points. These three park are joined together by two soft brass rivets, with counter-sunk heads, to prevent separation in handling. A groove is cast in the iron, and a corresponding rib on the bronze, to prevent the latter from turning with the axle when in place. In renewals it is ordinarily necessary simply to drive out the rivets and renew the bronze and lead. The iron part is not subjected to much wear and should last for years. It is evident that the first cost of these journals, and also the cost of renewals, must be much less than the old form. This difference amounts, at the present price of materials, to $9.60 for an eightwheel car, in first cost, and $4.72 for renewals. These bearings have been in use, and found to do what is claimed for them.

Jan 1, 1880

CARL A. WENDELL, New York, N. Y. (written discussion*) .-I have never seen in print anything that even remotely has approached this article in clearness and important conclusions in conjunction with work done on the sink-and-float test. I have had many hundreds of these tests made and on different specific gravity solutions and the resultant product analyzed, but I have never grasped nor been able to show what this article sets forth. This article brings out one factor very clearly to my mind; what is to take the place of the solutions of different specific gravities used to obtain the laboratory results, when it comes to washing on a large scale, since water has one constant weight only? The answer is, sizing of coal. And as we know the importance of size versus specific gravity of the material to be washed, perhaps defined (practical) lines can ultimately be gotten up so that the sizing, if any, may be determined at the same time as the laboratory work on the coal is being done. G. R. DELAMATER, ? Steelton, Pa. (written discussion?).-The authors' deductions are well founded and although they disclaim any wide experience in commercial coal washing, practically all of the data presented are applicable to coals of all parts of this country. The paper clearly sets forth the great necessity of careful preliminary investiga-tion of each contemplated washery undertaking and contains the follow-ing very true statements. "It is not safe to assume that any coal which can he successfully washed on coarse coal jigs can be cleaned more com-pletely by washing at a finer size on tables," and "The effect of finer crushing upon the completeness with which impurities may be separated from coal depends upon two opposing tendencies. First, that the more finely a raw coal is crushed, the more completely will the particles of impurities be detached from the particles of clean coal. Second, the finer a coal is crushed the more difficult it becomes to separate the pieces of clean refuse from the pieces of clean coal."

Jan 12, 1919

The discovery of minerals in any community, especially precious minerals, gives a sense of hope and optimism about development prospects within the community. However, the euphoria surrounding such a find could be short lived if the wrong perception is created at the inception of the project, that the exploitation of the mineral resource will pose a serious problem to the community. The socio-economic impact can be negative or positive but if not properly handled, the negatives will outweigh the positives. Illegal mining activity, popularly known as Galamsey in Ghana, is a typical example of the negative impact of the mineral industry. Galamsey activities have resulted in an increase in school drop-out rate, pollution of water bodies affecting entire communities bringing a lot of health problems, destruction of farm lands, destruction of rail lines resulting in transportation problems, armed robbery, prostitution, just to mention a few. The improvement of the water supply system in the surrounding communities, implementation of sustainable development programs, improvement in the infrastructure, are just a few examples of positive socio-economic impact.Factors responsible for the socio-economic and environmental impact include: the unwillingness of most companies to invest substantial resources to deal with environmental issues, lack of adequate professionals with the requisite appreciation for environmental issues related to their activities, realisation that support of surrounding communities is key to successful operations, the now globally accepted view that multinational companies should invest in the socio-economic lives of the surrounding communities, etc. In order to ensure the prevention of the negative impact of mining activities on local communities, there should be a paradigm shift in the way the training for the new crop of mining and metallurgical engineers have been structured in the past, social contract with the local communities must be drawn and implemented; it must not be an imposition on the communities but rather a contract arising out of extensive interactions between the industries and the local communities. Environmental awareness has reached a level where communities affected by the minerals industry, to a very large extent, know what they should tolerate and what they should not. There is therefore the need to ensure that effective systems are in place to exploit mineral resources without damaging the environment.

Jan 1, 2008

By R Lloyd

Coal Services (Health and Safety Trust) funded ARRB Transport Research Ltd to investigate fatigue and performance of truck drivers over consecutive shifts. The main questions were to assess: What is the most important contributor to acute fatigue in mining? Is it length of shift (eg eight hours versus 12 hours) or is it time of day (eg circadian effects)? What is the limit of successive day or night shifts before chronic fatigue affects operator performance in open cut mines? The project methodology included utilising ARRB Fatigue Monitoring Devices (forced-choice stimulus reaction) in eight haul trucks, testing 24 subjects over several weeks. Each subject filled in a Fatigue Risk Questionnaire on lifestyle and health. Operators worked a 14-night, one day off, 13-day roster of 12-hour shifts in a fly-in/fly-out operation with excellent opportunities for restorative sleep between shifts. A total of 3500 hours of real-time data was collected, representing the first set of objective, real-time driver performance data for Australian mining. The data showed that for a single night of driving haul trucks, there appears to be no effect on operator fatigue from the amount of time on task (for the 12 hours). In fact performance was worse through the first eight hours than the last four. The circadian influence had a stronger affect than working more than eight hours. Of the 14 nights worked at the site, nights 13, 14, seven and two respectively, were the worst. This presents a conundrum for policy makers who may like to place caps on working hours or rosters in the hope that it will alleviate the fatigue issue. It will not. The major finding within this study is the combined influence of circadian rhythms (human body clock) and individual variability on performance. The lifestyle habits and the health of individuals have a profound effect on operator performance as shown by the strong positive correlation between high fatigue risk scores from the Fatigue Risk Questionnaire and poor performance. An individualistic approach would appear to have the best chance of reducing high potential incidents due to fatigue through successive nightshifts.

Jan 1, 2005

The complete life cycle of a production facility has many phases requiring many different skills and many different personalities. It is not unlike the life cycle of a person and many parallels can be drawn from it. I leave some of these analogous situations to your fertile minds. The author, having worked in operations, plant design, plant commissioning, marketing and many other interesting situations through the industry has drawn from this experience and examples given by many associates in the industry.The phases seen are as follows: Concept Studies û someone has a bright idea of how to make a dollar. Scope Studies û what possible processes/options that could make a dollar. Prefeasibility Study û the æviableÆ scope options are studied to develop feasible options. Feasibility study û defines the concepts that should be designed to make a viable project thus enabling financing and project commitment to be made. Detailed Design û an intermediate step that consolidates the inputs to give a robust plant that can be constructed.Construction û people can see what they thought was going to occur and start to understand the plant. Commissioning û the hand-over of æownershipÆ from the conceiverÆs to the operators. Operations û the ætoyÆ has become reality and money must be made. De-commissioning û the plant has seen out the useful life of the ore deposit, it now goes through a further process required by society.Across these phases of plant design run several countervailing management requirements that can influence the outcome of the plant design. Some of the management rigours that have to be applied to the various phases are as follows: costing basis of the various phases; operational and maintenance reviews; sustainable development; risk assessment; reliability reviews; equipment availability; commissioning time; and environmental review.This paper endeavours to awaken people to the phases that projects require for a successful outcome and the management rigour that has to be applied throughout the phases to ensure the correct intellectual horsepower is applied at the right time to ensure the best outcome.Many of you would be parents and realise this is not unlike the development of children, teenagers, adults, retirees and ongoing.

Jan 1, 2002

By M. Gensamer

IT has been suggested by a number of people that it would be worth while for some one to attempt to summarize or condense the proceedings of this symposium. This task has fallen to me as organizer and co-chairman. Its difficulty will be appreciated by anyone who attempts to read the whole proceedings. It is therefore with trepidation that I offer the following digest. In recent years there has been a renewal of interest in America on this subject of the cohesive strength of materials, and a growing appreciation of the need for a better theory of cohesion failure. The theories of elastic action and plastic action are well developed, particularly the former. The theory of plastic action is still in the course of development, but it is well along. Plastic action is terminated by cohesion failure and what is needed is a theory that will tell us when to expect the cohesion failure. In the past it has generally been assumed that cohesion failure will occur when a critical value of the maximum tensile stress has been reached. Many experiments have shown that this is not strictly true, and this symposium concerns itself with the failures of this simple hypothesis, and with the efforts that have been made to devise a more satisfactory theory. The most active contributor in recent years to knowledge in this field is Dr. McAdam, and he was asked to open the symposium with a summary or condensation of his papers and views. Undoubtedly it is presumptuous to attempt a still greater condensation, but perhaps it will be useful, because even his contribution to this symposium contains no summary, no concise statement of just what his contribution has bees. Dr. McAdam makes two main points. The first is that the cohesive strength is not a single valued quantity, but that it is a function of all three principal stresses and hence must be represented diagrammatically by a surface in a three-dimensional figure. Dr. McAdam has attempted so to delineate the cohesion limit, basing his

Jan 1, 1944

By James Douglas

An address before the Meeting of the New York Section, Nov. 4, 1914. As life advances one is inclined to look backward instead of forward, and the vista over which my memory carries me has been filled with such a shifting panorama of changes in metallurgy that the whole practice of the art seems to have been re-created. The first cupola furnace that I saw in operation was at one of the group of mines at Capelton, Quebec, from which the Nichols company still draws some of its sulphur supply. At that time it was operated by a Hartford, Conn., company, under a General Adams. When its small brick furnaces made a campaign of a week and smelted 10 tons a day, the feat redounded to the credit of the operator. The introduction of the water-jacketed cupola dates forward to the next decade. I was using one in Pennsylvania, making copper matte, to the horror of a noted metallurgist, who could not conceive it possible that you. could bring fused sulphides in contact with steel without rapid corrosion. In our ignorance we were doing what seemed to be an impossibility, and it is just that recklessness and disregard for precedent which has characterized so much of the work of American metallurgists, and carried us forward at such headlong speed. Once the water jacket was accepted as the type of the. copper cupola, its almost unlimited expansion in length, but not in width, was a matter of convenience rather than of skill. In Butte the cupolas have been enlarged by adding furnace to furnace. The first reverberatories which I saw in operation were those in Professor Hill's Black Hawk establishment, where the concentrates from the Gilpin County gold mills were run down into matte for separation in England. Sixty dollars per ton was the usual deduction in those days before gold and silver was paid for. Smelting was done with wood as fuel, and the capacity of the furnace was about 10 tons per diem. Shortly after this Professor Hill formed an alliance with Richard Pearce, who was running what, if I recollect aright, was called the Swansea Works, at the bend of the river approaching Georgetown.

Jan 4, 1915

By Thomas Read

READJUSTMENT Of the industrial world to a peace .basis after more than 4 years of war will involve many fundamental and far-reaching changes that cannot as yet he clearly foreseen or definitely provided for. Such problems may be subdivided, in the vocabulary of war, into those involving material and those centering about personnel. Of the two, the-latter group is the more difficult and obscure, as the factors involved are less clearly understood and the methods to be followed are not yet tested and standardized. When it is said that the market is weak, stocks large, and demand light, every business man understands clearly what is meant and. what course he should adopt to adjust himself, so far as possible, to such conditions. But when it is said that the rapid spread of Bolshevism in Europe is a danger to industrial organization in this country, it is difficult to have any assured sense that all that the statement may mean is clearly understood or that the means to be followed to meet such a situation are definitely known. Since Bolshevism is primarily a mental phenomenon and since the rupture it brings about in industrial organization should be prevented, if possible, it is my purpose to restrict this discussion of the activities of the Committee on Industrial Organization to some of its mental aspects, as the chairmen of the sub-committees, from their special knowledge of their own fields, can best set forth recent progress in the lines with which they are especially concerned. The first requisites of success in industrial organization, as in the biological organism of which it is the social counterpart, are unity of purpose and coordinated activity. Typical good and bad examples of this are the relative parts that the United States and Russia have played in the great war. These two factors are primarily mental, and it is not difficult to view the mental aspects of all problems of industrial organization as the most important ones. Unless we can attain unity of purpose and coordinated activity in industry, the provision of comfortable homes at reasonable rent, the assurance of steady work at good wages, the

Jan 2, 1919

By M. Gensamer

It has been suggested by a number of people that it would be worth while for some one to attempt to summarize or condense the proceedings of this symposium. This task has fallen to me as organizer and co-chairman. Its difficulty will be appreciated by anyone who attempts to read the whole proceedings. It is therefore with trepidation that I offer the following digest. In recent years there has been a renewal of interest in America on this subject of the cohesive strength of materials, and a growing appreciation of the need for a better theory of cohesion failure. The theories of elastic action and plastic action are well developed, particularly the former. The theory of plastic action is still in the course of development, but it is well along. Plastic action is terminated by cohesion failure and what is needed is a theory that will tell us when to expect the cohesion failure. In the past it has generally been assumed that cohesion failure will occur when a critical value of the maximum tensile stress has been reached. Many experiments have shown that this is not strictly true, and this symposium concerns itself with the failures of this simple hypothesis, and with the efforts that have been made to devise a more satisfactory theory. The most active contributor in recent years to knowledge in this field is Dr. McAdam, and he was asked to open the symposium with a summary or condensation of his papers and views. Undoubtedly it is presumptuous to attempt a still greater condensation, but perhaps it will be useful, because even his contribution to this symposium contains no summary, no concise statement of just what his contribution has been. Dr. McAdam makes two main points The first is that the cohesive strength is not a single valued quantity, but that it is a function of all three principal stresses and hence must be represented diagrammati-cally by a surface in a three-dimensional figure, Dr. McAdam has attempted so to delineate the cohesion limit, basing his

Jan 1, 1945

By Steve Kral

The list of environmental issues facing industry in general, and the mining industry in particular, has placed greater emphasis on the concept of risk assessment and risk management. In informal terms, risk can be defined as the chance of injury, loss or damage. More formally, it is defined as the probability of an occurrence and its consequences. In simple terms, risk assessment involves three questions: What can go wrong? How probable is it to go wrong? If it goes wrong, what are the consequences? Experts on the subject of risk assess¬ment and management met in St. Louis, MO in October 1992 to discuss the extensive and innovative technology that has been developed in this arena. Each agreed that a consistent framework can be used to approach risk assessment/ management considerations in siting and design alternatives, as well as when considering financial aspects of mine development. And the environmental planning process for mines, as well as planning for operation through closures, will rely more heavily on risk assessment and management techniques. Risk assessment is a tool to assist engineers, scientists and managers make better, defensible operational decisions. A realistic and probabilistic risk analysis, coupled with a sound financial model, can combine a large set of alternatives and criteria to arrive at a defensible decision. Organizers of this regional SME conference believe that mining professionals should become fully conversant with risk assessment techniques and approaches because this arena provides opportunities to develop more rational decision-making techniques. Current health risk assessments rely heavily on Environmental Protection Agency (EPA) approaches. Several speakers and papers show how this approach has been applied to a variety of topics. Two major advantages come forward when applying risk assessment techniques to environmental clean-up options for contaminated sites. They are the selection of practical options and cost-effective alternatives. A probabilistic risk assessment provides results that can be directly related to clean-up costs. It has been shown that small reductions in risk are obtained for large increases in cost after a certain threshold value is reached. A preferred, practical clean-up alternative that provides permanent solutions can be selected based on a probabilistic assessment. Here are summaries of some of the papers presented at the meeting.

Jan 1, 1993

By Charles Schwab

WHEN I leave this life, as an employer of labor there is no one thing that I want so much to be engraven upon my monument as the fact that I have been one of the men who have worked, whether with my brains or my hands, for the advance-ment of industry in the United States, and to be regarded, as I should like to be regarded by labor with love and kindly remembrance for our years of association. In my relationship with my employees, I have always contended that every man should be paid for what he does. I will not employ or be associated with any kind of labor of which the organization insists that a man shall receive a fixed sum of money for his day's wages, however poor or good his day's labor may be. What applies to the common laborer applies equally well to the management, the brains of an industrial establishment. I have always thought of industry as a three-legged stool, with capital, management and labor as the legs. All three legs of that stool must be there before that stool can stand up. If you take any one of those legs away, it is going to topple over. The. three must stand together for successful business accomplishment. I believe that a man who has his labor to sell, to put it plainly, has just as good a right to bargain for the best price for that labor as those who employ him. It is a perfect right for him to do so. If the government of our United States is right, our method of handling labor in our Bethlehem plants is right because it is representative and democratic. We have our labor elect delegates; elect representa-tives from their own ranks, who shall meet frequently. That constitutes, as. it were, the House of our great Congress in Washington, the industrial house. We have our management, who represent the Senate, who meet independently. Working men have learned to express their views freely as to whether they are treated fairly and whether conditions are right or wrong.

Jan 12, 1922

By Paulo Roberto Pereira

This paper is motivated by the belief that increasing drilling and blasting costs will not necessarily bring about better digging or crushing productivity. As a matter of fact it can be counter productive as the ensuing discussion will show. In the two case studies presented herein when powder factor increased, productivity at a rope shovel and at a primary crusher decreased. Experience has shown that equipment (shovel and primary crusher) productivity increases as the powder factor increases and concurrently operating costs decrease. This is illustrated by Figure 1where the graph shows (assuming drilling costs constant) that for increases in powder factor initially operating costs might fall till a certain point and then they start to go up again. By the same token we need to understand what is the behavior of the operation’s productivity. It seems intuitive productivity goes up for increases in powder factor but when an operation reaches the point of minimum operating cost one could say that productivity reached its maximum. For continuing increases in powder factor can productivity still go up or does it go down? This paper presents two examples where the productivities of a surface coal mine and of a quarry are reduced for increases in powder factor. This indicates that these two operations could be operating to the right of their minimum operating costs and maximum productivity and therefore wasting precious drilling and blasting dollars and resources. Moreover, their productivity is following the red dotted line in Figure 1 and the question becomes can they follow the blue dotted line for increased drilling and blasting costs? The industry owes to itself to determine this minimum operating cost point and what can be done in case that the productivity goes down afterwards despite an increase in drilling and blasting costs. In other words, utilize your drilling and blasting resources correctly. In the two examples that follow single explosive loading strategies make powder factor a valid means of comparing the results of productivity as a function of powder factor. Also, external factors such as equipment operator influence are eliminated due to the long time span considered in the analysis

Jan 1, 2005

By H. Ries

In the marketing of mineral products, it is always highly desirable for both the producer and the consumer to be able to discuss things in a common language, and this can only be done if there are standard methods for expressing the properties of the raw materials. Having developed such a form of expression, the next step would be the making of specifications, which may serve as a basis for selecting raw materials. Considering the large number of non-metallic minerals that are used, there are not a few for which there are no standard laboratory tests to be used in determining their properties, or even standard specifications on which grades or market price may be based. Indeed in many cases the consumer simply requests the producer to submit samples, and rejects or accepts them without any explanation. Could the producer know in advance just what the consumer needed, time and money might often be saved. It appears to the writer that it is of the highest importance to devise standard laboratory tests wherever possible, as this enables the consumer to state definitely what he needs, and is of great assistance to the producer. It should also work to reduce misunderstandings and disputes. In the case of sands, we find that they show a wide variation in their character, ranging from those that are so coarse as to be of gravelly nature to those that are so fine that they might be classed as silt; and from very clayey ones to those that are practically free from clay. For this wide range of sands, we have a corresponding variety of uses, which are based mainly on the physical properties of the sand, although these are not always very definitely stated. The chemical composition need rarely be considered, if the sand is of siliceous nature. To determine and express these properties there should be standard tests, which are to be followed in all cases where the material is tested in the laboratory. The use of sands for foundry work (making molds or cores) is old, and it has been recognized for some time that the important properties to be

Jan 1, 1926