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By Norman Weiss

The purpose of this paper is to relate progress in the engineering field called Minerals Beneficiation to undergraduate and graduate education in our colleges and universities. So mach has been written recently about the education of scientists and engineers that I've had to struggle against the temptation to repeat what has been often said before, particularly because man like Robert Mehl of Carnegie Tech, Antoine Gaudin of MIT, H. M. Davis of Penn State, and John Vanderwilt of Colorado School of Mines have recently written many quotable paragraphs on the subject. In the matter of progress, the rapidity of proliferation in the area of physical and chemical beneficiation is convincing proof that this is indeed a lively art, and having been a millman for 35 uninterrupted years I prefer to lean on personal observations to some extent, rather than on statistics and charts v culled from the journals. I propose in this paper to talk first about the progress we've made in our branch of the mining industry in the last 3 decades--particularly in the last few years--and try to show that future progress will depend upon the quality of education and capacity for research possessed by our colleges. The second part will deal with some of the problems the colleges encounter in trying to fulfill these responsibilities.

Jan 1, 1959

By W. Jack Wilkes, Gilbert L. Butler

TRANSPORTATION TUNNELING The use of tunnels for transportation, namely rapid rail transit systems and highways is on the increase. How much that increase might be through the 1980's is the question that is discussed in this paper. In 1975, there were 218 route miles of subway tunnels for rapid rail transit and 154 lane-miles of highway tunnel. From the viewpoint of many transportation planners and designers, the tunnel is one of the tools which may be used to by-pass many types of obstacles: a mountain, a body of water, or a Central Business District (CBD). Therefore, the transportation tunnel is a rural as well as an urban solution with major emphasis on the latter because of the current transportation needs of our cities. In the case of rural locations, tunnels are usually constructed through mountains in order to eliminate miles of steep grades and dangerous curves, such as the Eisenhower Tunnel which cuts through the Continental Divide in Colorado along 1-70 and saves 10 miles and 40 minutes of driving time. Tunnels also provide an excellent transportation link across bodies of water in order not to interfere with shipping lanes. The Chesapeake Bay Tunnel and Bay Tubes of the BART system are excellent examples of this type of tunnel.

Jan 1, 1976

By Richard C. Sale

INTRODUCTION The topic of the paper is to discuss the use of micro computers in the construction industry. I will first discuss the present situation of the PCs in our industry followed by a discussion how Guy. F. Atkinson has integrated the PCs into it's organization. I will close with some general comments that any organization should review in order to enhance the use of their PCs both at the job sites and home office locations. PRESENT SITUATION OF THE PCs IN OUR INDUSTRY Today, the possible number of combinations that can be obtained when bringing together the available models of PCs, with their peripherals and software, is astronomical. With this array of equipment that can be bought, plus the new and possibly better equipment that is being put on the market almost daily, it is indeed a very difficult task for an organization to know how to invest its money in computer equipment. At the job sites, the work is fast paced with little time available to fully learn what the PCs can do to help with the required paperwork. I am still waiting for the day when someone has to tell the superintendent at the job site that he cannot start pouring concrete or shoot the next round because no one can get the computer to work.

Jan 1, 1987

By J. Smolensky, M. Paul

The Nordhalde is a waste rock pile resulting from uranium mining near Ronneburg, Germany. The pile contains over 27 million m3 of waste rock. Typical seepage water has a pH of 2.7 and a sulfate concentration of 10,000 mg/L. Geochemical investigations of the Nordhalde from 1993 to 1996 included drillholes, test pits, ABA and metals analyses, column tests, and a detailed review of the construction history of the pile. In 1996, eight drillholes were instrumented for monitoring oxygen and temperature. Monitoring continued for a fill year. Hourly temperature and pressure readings were taken by automated data recorder. Oxygen concentrations were measured three times per week, and periodic gas samples were obtained for complete analysis. The resulting data set is believed to be one of the most comprehensive of its kind. Effects noted elsewhere, such as thermal convection, are evident. However, unlike other data in the literature, the NordhaIde data shows a strong seasonal effect, with convection dominating oxygen transport only in the winter months. Analysis of the data allowed the amount of contaminants associated with ongoing and historical oxidation to be compared, and results were used to assess the potential effectiveness of proposed remediation measures.

Jan 1, 2000

By Sean Masse

New Gold?s New Afton Mine, located 8 km (5 miles) west of Kamloops, British Columbia, is a 4.5-Mt/a (5-million stpy) block cave mine, making it the highest tonnage underground hard rock mine in Canada. The reserve is estimated at 52.5 Mt (55.9 million st) with grades of 0.65 g/t (0.02 oz/st) gold and 0.93 percent copper (2012). Commercial production was achieved in July 2012 and nameplate production was achieved ahead of schedule in September 2012, with the cave breaching to surface in 2013. The mill has a SAG and a ball mill with a froth flotation circuit.

Jan 1, 2014

By Ned M. Smith

The Mississippian Salem Limestone, from which dimension stone is quarried in Indiana, is principally a calcarenitic rock formed of fossil bryozoans, echinoderms, and specimens of Endothyra. Numerical associations of the fossils, binding materials, oölitically coated fossils, and voids were determined by counting points on the surfaces of 278 thin sections of the limestone. Median sizes, coefficients of sorting, and skewness numbers were computed from measurements made of constituents in these thin sections. Many other samples and numerous exposures of the Salem and contiguous parts of adjacent formations also were studied. The organisms that furnished the skeletal material for formation of the Salem Limestone were chiefly gregarious and communal. Salem rocks are formed of nearly whole skeletons, of dismembered or slightly damaged skeletons, and of skeletons thoroughly ground up, because currents in the Salem sea varied in their ability to move and damage these materials. Locally the sediments are of uniform grain size because of sorting by currents and because related organisms grew to similar sizes. Rocks of the formation contain different proportions of the fauna both because the animals lived in these proportions and because their skeletons were mixed together by currents. The proportional relationships between members of the fauna were constant locally and for short periods of time. Study and mapping of the faunal associations, numbers of oölitically coated fossils, bedding structures, and size parameters enables geologists to suggest sedimentologic histories and sequences in areas of various sizes. Interpretations based upon such areal studies are necessary for evaluation of the dimension-stone potential within the Salem Limestone.

Jan 1, 1966

By X. Wen, D. Tao, B. Li

A high effective method using a hammer mill, a column pneumatic separator and an electrostatic separator was studied for recycling copper from waste printed circuit board. The factors influencing the copper liberation degree and following separations were discussed. Two different physical separating methods were compared and discussed. Experiment results show that a well-controlled impact action can produce a satisfactory degree of copper liberation at a relatively coarse particle size. Around 90% copper recovery from printed circuit board for coarse particle size can be achieved by using a combination of electrostatic separation and pneumatic separation.

Jan 1, 2003

By Takeshi Shinohara

It is a great honor and pleasure for me as President of the Japanese Tunnel Association to send greetings to the 1974 Rapid Excavation and Tunneling Conference. Recently in Japan, the Japanese Tunnel Association was established as recommended by the OECD Advisory Conference on Tunneling. This is a central organization concerned with tunnel construction consisting of government authorities, universities' research institutes and construction firms as well as manufacturers of relevant materials and equipment. As I was chosen the first president of the newly-established Japanese Tunnel Association, I would like to avail myself of this opportunity to announce to you its establishment and its earnest wish to contribute to the development of tunneling technique not only in our country but also all over the world. At the same time, I cordially request your friendship and cooperation for the benefit of further development of tunneling techniques on both sides of the Pacific. At present, many tunnels are under construction in Japan. The total length of tunnels under construction for railways and highways is about 600km including the 54km Seikan Undersea Tunnel which connects the Main Island and Hokkaido. Naturally, for construction of such tunnels in Japan, we have introduced much equipment and technique from the United States and other foreign countries. Now with accumulated experience, we are confident to be able to furnish various useful information concerning tunnel construction.

Jan 1, 1974

By J. Roth

PROLOGUE Nowadays, where production costs and energy costs are increasing and at the same time requirements in fineness and purity of industrial mineral products are getting higher and higher, industry has to look for more efficient grinding systems and developments to produce these products more economically. Therefore lots of new developments in high energy jet mill pulverizing have been made. In the main, however, these developments involved more or less just the new principle of fluidized bed jet pulverizers but not the older spiral jet mill principle. In some cases, especially in the filler industry where laminar minerals are used and higher aspect ratios are required, the spiral jet mill principle has advantages in a better delamination of these minerals. To comminute minerals down to products with a d97 < 3 µm, the specific energy consumption increases up to 2,000 kWh/t – 3,000 kWh/t or even more, depending on the grindability of the mineral. So the production of these fine materials is quite an expensive task. But jet mill grinding is and will be the most favorable method to produce micro-products and in the near future nano-products, despite the high energy consumption.

Jan 1, 2000

By S. K. Sharma, D. A. Stanley

The US Bureau of Mines is investigating the fundamentals of the flocculation process. The objective of this study was to determine the effects of various physico-chemical parameters, namely, shear rate, polymer dosage, and polymer concentration, on floc growth and to determine the applicability of a model for predicting polymer flocculation behavior. A rapid in-line particle size analyzer was used to follow the progress of both the floc growth and the breakage as a function of time. A genetic algorithm (GA) was used to determine the unknown parameters in the model and to fit a curve to the experimental data. The results showed that the model reproduces the experimental data with only reasonable accuracy and that it was relatively insensitive to the parameters. Results of the flocculation study showed that increases in the polymer dosage had a greater effect on the time required to reach the maximum floc size than on the floc size itself: It was also determined that, given all the above parameters, the degree of slurry mixing during the flocculation process had the greatest bearing on floc growth.

Jan 1, 1995

By Andrew L. Mular

Methodology to model, simulate and optimize full scale mineral pro- cessing circuits in production environments is reviewed and evaluated. Strategies for data acquisition and adjustment are considered along with techniques to fit models to adjusted data. Examples are considered for clarity.

Jan 1, 1989

By B. Cavender

Mining managers trying to rapidly reduce production costs tend to implement a traditional set of topdown managerial practices: reductions in production volume, employee layoffs, renegotiation of supplier contracts, cancellation of employee training, restrictions on travel, reductions in office supplies, and so forth. While these practices do reduce costs, the benefits are often limited in both magnitude and duration, and the workforce is usually left demoralized. Successful cost-cutters take a different approach. They make the continuous reduction of costs a priority for all members of the organization, whether managers or workers. The culture of these firms emphasizes the commitment, voluntarily given, of individuals and work groups to this goal. Cost-cutting practices often reject all of the traditional methods mentioned above, but are far more numerous, innovative and successful. This culture of cost reduction is the result of a set of leadership competencies that establish direction for the organization, align the organization&apos;s various constituencies with this direction, and motivate and inspire the organization. Cost reduction then becomes a routine task rather than a heroic achievement.

Jan 1, 2002

By Robert A. Cortese, Carrie E. Lucci

Mine Safety and Health Administration (MSHA) regulations require underground coal mine operators to dust their mine corridors with an inert material to prevent coal dust explosions. The most commonly used material is pulverized limestone. Current practice to determine compliance with MSHA regulations requires the coal mine foreman or an MSHA inspector to collect samples of the deposited dust, a mixture of coal dust and limestone rock dust, for above ground laboratory analysis. To expedite this process, the U.S. Bureau of Mines has developed two instruments to facilitate the inspection and rock dusting processes, the explosibility meter and float dust deposition meter. The explosibility meter is a hand-held instrument which provides an in situ measurement of the explosible nature of homogeneous mine dust samples. The float dust deposition meter measures the mass loading density of the top layer of coal or limestone dust deposited on the mine floor during mining operations by the ventilation air. It may also be used to automate trickle rock dusting equipment. The operation of each device is based on the difference in the optical reflectance between the light limestone dust and the dark coal dust. The principal of the explosibility meter is based on the observation that, for a fixed coal volatility, the optical reflectance of dust mixtures is relatively constant at the limit of flammability, and independent of the coal dust particle size.

Jan 1, 1995

By P. R. Taylor

Recent research by the investigators has evaluated the oxidation roasting of refractory gold concentrates in the presence of hydrated lime. (Taylor, 1990, 1991, 1992, 1993). These results have indicated that it may be possible to roast concentrates in such a way as to contain nearly all of the sulfur and arsenic in the roaster calcine and that cyanidation may be possible. To further evaluate the behavior of this type of roasting system a laboratory cyclone reactor was built and operated using pyrite and hydrated lime as a .model system. Approximately 50 years ago, the principle of cyclone firing entered practical boiler construction. The appeal of the cyclone configuration was that it afforded the flash combustion process greater efficiency due to turbulence-induced increased mass transfer, heat exchange, and combustion rates.

Jan 1, 1994

By T. E. Wilson

An exploration bore core sample of coal ought to be reduced from its original cylindrical form to a particle size distribution and particle composition that reflects, insofar as possible, a process stream of? raw? coal it represents. Often, coal cores are reduced with a laboratory crushing machine, the product of which may not match the raw coal size distribution or size fraction composition. This study employs drop-shatter impact breakage followed by dry batch tumbling in a steel cylinder rotated about its transverse axis in order to characterize the core material in terms of first-order and zeroth-order breakage rate constants. These are indices of the propensity of the coal to degrade during excavation and handling. Initial drop-shatter and dry tumbling tests were done with synthetic cores, to reduce material variables and . conserve difficult-to-obtain coal cores.? Cores of three different coal beds --Illinois No.6, Upper Freeport, and Pocahontas No. 5 -were subjected to drop-shatter and dry batch tumbling tests to determine breakage response. Comparison of coal preparation plant feed with a crushed bore core and a bore core prepared by drop-shatter and tumbling (all from the same Illinois No.6 coal mining property) indicated that the size distribution and size fraction composition of the drop-shattered/tumbled core more closely resembled the plant feed than the crushed core.

Jan 1, 1998

By G. Bryant, P. Ziemkiewicz

Acid mine drainage (AMD) from both abandoned surface and underground mines is a serious problem. The flow of water and changes in quality over time from abandoned mines is important in determining remediation strategies. Acid mine drainage from surface mines is estimated to last for 10-20 years, while estimates of acid drainage from underground mines vary from 10- 100s of years. Fifteen underground mine discharges in West Virginia were studied to compare water quality changes between 1968 and 1999 to see if our data are consistent with other studies. Each of the discharges were categorized into one of three groups: undisturbed since 1968, affected by surface mining since 1968, and reclaimed. Comparing water quality between 1968 and 1999, the discharges in the undisturbed category showed a 35 to 95% improvement in acid concentration and a 40 to 99% reduction in iron concentration. The discharges affected by surface mining showed the most dramatic improvement. For acidity, iron, and aluminum, the percent improvements were all above 44%, and in most cases in the 70 to 99% range. In the reclaimed category, one of the four discharges declined in water quality. Discharge 82 showed a 76% increase in acidity, and iron and aluminum concentrations worsened by 58 and 96%. However, discharges 15 and 74 improved in water quality with a 94% acid load improvement and a 95% iron load improvement at both sites.

Jan 1, 2000

By Gustavo A. Aristizábal-H, Oscar J. Restrepo-B, J. Alejandro Delgado-J

"In Antioquia region of Colombia – South America most of extractive activity is developed as artisanal and small-scale level, exploiting different types of minerals resources but predominantly gold. This is not only an ancestral livelihood of hundreds of families in this region, but also their unique way of subsistence. However, that situation has not had a positive effect in the sustainable development of this territory because of several unsustainability factors mainly related to mercury use for gold extraction, the incorrect management of tailings and the informal way in which miners perform their activity. In 2010 Antioquia was the place with the highest contamination by mercury in the world with serious effects in ecosystems and health of habitants of this region (Veiga 2010) This paper presents a Socio-Technical Model focused on strengthening capabilities and social capital of artisanal and small-scale miners and its surrounding communities in Antioquia region. This is based on processes of evaluation, design and implementation of appropriate technologies to obtain “clean minerals” without using mercury and with a right management of tailings. In gold extraction it is about gravitational methods of concentration, which take advantage of high density of this element. These methods not only are cleaner but more profitable for miners. Notwithstanding its technical origins, the current model proposes a holistic framework that manages the elimination of mercury in mining not only as a technology transfer matter. Thus, more than formalization the strengthening process seeks to promote a business vision in miners and to develop productive chains in surrounding communities, this means to improve the skills of artisanal and small-scale miners to organize in a corporative way and to help surrounding communities to provide support and supply services to mining and even to other companies. Besides, the articulation with local institutions drives to reinforce their functions of control and accompaniment. In shorthand, this effort aims to empower local institutions, miners and surrounding communities in such a way they are able to face together their own development challenges in a sustainable way."

Jan 1, 2017

By J. S. Wozek

In metallurgical applications, coal fulfills dual roles as a chemical feed stock and as a fuel source. These applications range from cokemaking, ironrnaking (including pulverized coal injection), foundry, basic oxygen furnace / electric arc furnace coal additions, direct ironrnaking, Corex, and the futuristic direct steelmaking. In all steelmaking related processes, chemical reactions are simultaneously temperature and chemical dependent. Therefore, coals used in these processes must consistently comply with specific quality parameters in order to promote efficient operations. This paper limits discussion of Metallurgical Coal Quality to cokemaking and ironmaking applications. Its purpose is to present the customer&apos;s perspective on the control of critical coal and coke properties.

Jan 1, 1994

By R. K. Mehta

An electrochemical coal oxidation model involving heterogeneous kinetics is presented. This model was tested by collecting current transient data on three coals assaying different ash content under varying operating conditions such as particle size, temperature, and % solids. In all cases, the model fitted the data very satisfactorily. Three intrinsic rate constants, namely mass transfer coefficient of Fe(II) Ions diffusing from solution to the anode (kma), mass transfer coefficient of Fe(II) Ions diffusing from solution to the coal surface (kmc), and chemical rate constant for coal oxidation with respect to Fe(III) at coal surface (k), were calculated. It was interesting to note that in this system, the mass transfer at anode was as important as the chemical reaction at the coal surface. The validity of this model was further demonstrated through a comparison of the activation energy of coal oxidation: firstly, by utilizing calculated chemical rate constant and assuming Arrhenius&apos; type of relationship: secondly, by utilizing conventional approach using limiting current values. The comparison revealed that agreement was quite close. This kinetic analysis is useful because such a model can be used in predicting the intrinsic rate constants so that the relative importance of mass transport can be rationally analyzed.

Jan 1, 1991

By R. L. Michalowski

The operation of mobile mining equipment near the crest of stockpiles and wastedumps is a potentially hazardous practice which often results in localized slope failures. A limit plasticity approach to determine the total admissible weight for moving loads near slope crests is presented. A three-dimensional analysis provides an upper bound solution to the load that can be applied to the top of the slope (dump point), and it also provides the critical distances of the load from the slope crests. The analysis accounts for the inertial forces generated by the deceleration of a moving load (e.g., a dump truck), and it also includes the drag resistance of the front wheels if the brakes are engaged. The results can be utilized to determine the safe operating distances for mobile equipment from the slope edge. This presentation will discuss the application of limit plasticity to the development of the local three-dimensional collapse mechanism. An example with realistic parameters also will be presented.

Jan 1, 1991