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By RAY LYMAN WILBUR

SINCE boyhood I have had a keen interest in mining engineering. To see the prospector with his pack outfit and his pan, followed by the assayer and the trained engineer, has always had -something of the lure of romance for me. It is appropriate that the American Institute of Mining and Metallurgical Engineers should hold a general meeting in California, since this State has long been a home of mining engineering. Here, after the early open methods of mining, it has been necessary for the universities to train men in geology and mining, so that the earth could be penetrated and the rich ledges opened. In the eighty years in which the mines of California have been offering experience to the miners of the world, we have seen mining engineering evolve from a comparatively simple art, covered largely by rule of thumb, into a complex group of specialties, each utilizing the very latest discoveries in the various fields of physical sciences. Mining, too, has become a great business requiring large financial support and the most careful handling. Those mining engineers who have applied new processes in special fields have thus been able to give a wide-flung range to their activities in all parts of the world. The hand of nature in distributing minerals over the surface of the earth has compelled the mining engineer to become a modern pioneer, facing the heat of the tropics as well as the frozen regions of the north. There has been a marked cosmopolitan aspect to mining engineering, since the engineer had to go wherever the prospector discovered favorable leads. This has meant dealing with the harshest of conditions, the handling of labor of all sorts, the control of sanitary conditions, and relations to all forms of transportation. Naturally this has called on some of the very best minds in all countries to unlock the stores of hidden wealth. To make them available for civilization has been the job of the mining engineer.

Jan 1, 1929

By Jon R. Maki

"EVTAC, an iron ore mine in Minnesota, had trouble meeting the customer’s pellet silica requirements. In addition, the mine plan was moving towards a lower grade ore and funding was not available for plant improvements to compensate for the change in ore or improving quality. Small changes to optimize various processing equipment resulted in significant improvements in both quality and productivity; for example, productivity on one mill line increased by 10% while producing lower silica concentrate. This paper will provide the methodology that allowed EVTAC to improve quality and productivity through process optimization with little capital investment.INTRODUCTION EVTAC, an iron ore mine in Minnesota, had trouble meeting the customer pellet silica requirements. In addition, the short-term mine plan was changing to a lower ore grade. Because of limited funds, EVTAC did not have the capital for investing in the plant to compensate for the ore change or to make improvements to lower product silica levels. Small changes to optimize process equipment resulted in significant improvements in quality and productivity; for example, one mill line feed rates increased by 10% while also producing a higher quality concentrate. These changes were sufficient enough to allow the mine to lower the target ore grade beyond their initial goal. At one time, a $3M flotation facility was considered as a way to meet quality with the new ore grade. However, the process changes were able to accomplish the same silica reduction with roughly a $50,000 investment in VFDs for sump controls. This paper will discuss some of the modifications that allowed EVTAC to meet the quality and production objectives with little capital investment. It also discusses the methodology used to make these process improvements."

Jan 1, 2014

By A. F. Silva, J. M. G. Sotomayor, V. F. N. Torres

Geotechnical monitoring plays an important role in the detection of operational safety issues in the slopes of open pits. Currently, monitoring companies offer several solutions involving robust technologies that boast highly reliable data and the ability to control risky conditions. The monitoring data must be processed and analysed so as to allow the results to be used for several purposes, thereby providing information that can be used to manage operational actions and optimize mining plans or engineering projects. In this work we analysed monitoring data (pore pressure and displacement) and its correlation with the tension and displacement of the mass of an established failure slope calculated using the finite element method. To optimize the back-analysis, a Python language routine was developed using input data (point coordinates, parameter matrix, and critical section) to use software with the rock mass parameters (cohesion, friction angle, Young’s modulus, and Poisson’s ratio). For the back-analysis, the Mohr-Coulomb criterion was applied with the shear strength reduction technique to obtain the strength reduction factor. The results were consistent with both the measured displacements and the maximum deformation contours, revealing the possible failure mechanism, allowing the strength parameters to be calibrated according to the slope failure conditions, and providing information about the contribution of each variable (parameter) to the slope failure in the study area.

Oct 1, 2021

By Leonard A. Wolff

"The 1980sfor the mining industry can be characterized as the survival of the fittest. High interest rates, low commodity prices, foreign subsidized competition and decreasing ore grades have contributed to a streamlining of the domestic mining industry in the United States, leading to the shutdown of operations or large cutback of work forces. The purpose of this paper is to look at the impact of a layoff on the employees of what was once a major uranium producer in south central Wyoming, twenty months after the final layoff and mine shutdown. INTRODUCTIONDecember 19, 1985, was the date of the final of three successive layoffs over a two-month period, leading to the complete shutdown of Petrotomics Company, a subsidiary of Getty Minerals Company. The final shutdown was due to a combination of depressed U3O8 prices and the takeover of Getty Oil Company by Texaco in January 1984.The layoffs affected 104 employees and included mine personnel, mill personnel and staff. Both hourly and salary workers were involved. The operation was considered non-union, however, a few mill hourly employees were unionized. At the completion of the layoffs. only a handful of employees remained for administrative and miscellaneous functions.For Getty employees, the terms of the merger agreement provided a generous level of separation benefits. The terms that were insisted upon by Mr. Petersen, Chairman of the Board for Getty Oil, stipulated that employees receive one month of severance pay, for each full calendar year of employment up to a maximum of two year's pay. This was the forerunner of what is now commonly known as the ""tin parachute”. All but the union employees of Petrotomics received these separation benefits. Union employees were covered by their separate, less generous, contract.Much of the literature that has been published in recent months has centred around the effects of layoffs on remaining employees, or the psychological effects on the severed employee. This study will emphasize the economic impact and ramifications due to a layoff, using the Petrotomics employees as a case example."

Jan 1, 1989

By N. Edmonson

An examination of the statistics of the world phosphate fertilizer industry since 1980 reveals an increasing tendency for fertilizer manufacturing activity to concentrate in phosphate rock mining areas. The economic justification for this resource-oriented strategy is clear. The choice between shipping phosphate rock, a comparatively low-value product, and shipping more valuable finished fertilizers will always be resolved in favor of the latter if cost considerations control the decision. The historical existence of substantial phosphate fertilizer manufacturing capacity oriented toward fertilizer-consuming activities and dependent on imported phosphate rock shows that narrow cost considerations have not always determined the industry's location. One is entitled to ask what conditions have changed to precipitate the observed relocations, and how permanent these changes are. These questions are the subject of this investigation.

Jan 1, 1995

By S. K. Kawatra

In most operating coal-cleaning plants, a significant amount of pyrite is recovered in the froth during flotation of high-sulfur coal. Reducing the pyrite recovery first requires that the primary recovery mechanism should be Identified, as different measures are required for reducing entrainment, locked-particle flotation, or true hydrophobic flotation. In this paper, evidence is presented which suggests that hydrophobic flotation is not an important mechanism for recovery of liberated pyrite from freshly-ground coal when the collector is a neutral oil, and that the bulk of the floated pyrite occurs either as a result of simple entrainment or by mechanical locking with floatable coal particles. Column flotation results are also presented which show that significant sulfur reductions can be achieved by reducing levels of entrainment.

Jan 1, 1992

By Maria Margarida Lima, Maria Lucelinda Cunha, Dora Algarvio

"The main goal of the present work is the quality improvement of the recycled aggregates produced by a construction and demolition waste (C&DW) recycling facility located in Montemor-o-Novo, Portugal. The recycling process was developed on a pilot plant scale with 50 t/h of capacity. Process operations are the hammer mill comminution, magnetic separation and screening.In order to improve the knowledge on the C&DW, a characterization procedure was implemented by hand-sorting, magnetic and density separation on representative samples. On the other hand, to improve the quality of the produced aggregates, the bar screen size fractions were analysed, according to the Portuguese Standard (NP EN 933-1 2000).Wood was identified as the critical contaminant, representing 17% by weight of the total contaminants. Sieving results showed that about 97%, 76%, 56%, 98% and 57% were on the correct size range, which lower results are probably due to the type of screens and/or the material characteristics of the recycled aggregates.IntroductionThe construction and demolition waste problemConstruction and demolition waste (C&DW) is generated by the construction activity, resulting from both, buildings or other structures construction and old structures demolition. As a reference, it can be told that C&DW comprises about 40 to 50% of rubbish (concrete, asphalt, bricks, blocks and dirt), 20 to 30% of wood and related products and 20 to 30% of miscellaneous wastes [1]. In Portugal, C&DW is classified in the LER (Portuguese nick name for the European Waste List), Chapter 17, and includes a diversity of wastes, like concrete, bricks, ceramics, bricks, wood, glass, plaster, copper, zinc, lead, iron, steel, as well as insulation and roofing materials. C&DW stream has several characteristics which make it particularly difficult to deal with and are summarized in the following five items.(1) Lack of information on quantities generated: In Portugal, the C&DW sector has been neglected over the past years, which meant that there are not consistent information concerning the quantities and composition of these wastes yet. Several estimates, based in different assumptions, indicate different results, which may vary from 219 Mt to 10 931 Mt [2]."

Jan 1, 2008

By N. S. Tanious

This work was completed prior to the author's appointment with the Nuclear Regulatory Commission (NRC). Therefore the views and conclusions contained in this paper are those of the author and should not be interpreted as necessarily representing the official policies or recommendations of the NRC. Reference to specific brands, instruments, or trade names is made to facilitate understanding and does not imply endorsement by the author or the NRC.

Jan 1, 1987

By Carlos F. Perucca, Maria Virginia Ramírez A.

"Chile based SQM S.A., exploits potassium chloride rich salts at the Salar de Atacama, in northern Chile. The process includes the solar evaporation of natural brines existing in the Salar salt bed, followed by conventional flotation to recover Muriate of Potash (MOP) for fertilizer use.This paper describes a structured method developed to aid in understanding the metallurgical response of the solar evaporated salts to conventional flotation. The method uses classical metallurgical data analysis combined with laboratory and plant-scale testing, and rudimentary mineralogical studies.As a result of the study, several changes were made to the flotation circuit which produced an operation that is much more consistent and easier to control, and has an increased recovery. An optimized circuit, currently being financially evaluated, has also been conceptually designed based on the findings of this work.INTRODUCTIONSQM S.A. is the world’s largest producer and distributor of specialty fertilizers, iodine, lithium, as well as a wide array of industrial and specialty chemicals. SQM is a public corporation whose shares are traded in the Santiago and the New York Stock Exchanges.SQM S.A. exploits the mineral rights at the Salar de Atacama in northern Chile. Its production processes involve the solar evaporation of natural brines existing in the Salar salt bed, aimed at the recovery of Potassium, Lithium and Boron compounds."

Jan 1, 2004

By D Adhikary, M Khanal, B Poulsen, H Guo

During longwall mining, the ability to reliably estimate the height of longwall mining-induced fractures is critically important in order to effectively manage mining-induced water inflows and aquifer interference. The extent of mining-induced subsurface deformation, fracture, surface subsidence and aquifer interference is largely controlled by local lithological conditions, mining methods and mine layouts. Therefore for the purpose of quantifying mining impacts it is imperative to incorporate the local geology and mine plan parameters in a mine scale model. Two different numerical models based on 3D continuum (Finite Element Method) and 2D discrete (Discrete element method) domains, respectively, are developed to incorporate the mine site parameters of a study site in Australia. Both the models are calibrated and validated with measured mine data. The continuum numerical modelling method is used to investigate the change in permeability of the overburden strata due to underground extraction considering the full 3D nature of geology and mine layout. The discrete element modelling method is used to simulate the initiation and propagation of fractures, allowing the caving of overburden strata to be represented in a realistic manner, and the permeability enhancement of the strata overlying the goaf to be calculated from first principles. Permeability enhancement in the discrete element model is a direct function of the fractures induced in the deformation/caving process; fracture location, extent, aperture and connectedness. From the numerical modelling under the simulated condition for the mine studied here, it is predicted that the permeability of the caving zone from the goaf to five times the mining height increases by almost six orders of magnitude. In the fracture zone to approximately ten times the mining height, the change in permeability is predicted to be around two to three orders of magnitude. At the height of more than ten times the mining height the magnitude of permeability increased is predicted to be one to two orders of magnitude. CITATION:Khanal, M, Poulsen, B, Adhikary, D and Guo, H, 2018. Modelling of height of connective fractures during longwall mining, in Proceedings The Fourth Australasian Ground Control in Mining Conference (AusRock), pp 254–265 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Nov 30, 2018

By Takeshi Yoshikawa, Kazuki Morita, Yuichi Kato

"A composite composed of carbon fiber and a Cu-Si alloy is a promising candidate for next generation brake disc materials used in high-speed trains. The composite can be prepared by vacuum infiltration of the Cu-Si alloy into the fibrous carbon matrix. The activity of Si in the alloy plays an important role in controlling the formation of SiC; this formation is attributed to the reaction between the Si in the alloy and the carbon fiber during the infiltration process. Because Fe has strong affinity with Si, the addition of Fe is expected to decrease the activity of Si in the alloy. In the present work, the variation in the activity of Si in the alloy with the addition of Fe has been investigated by equilibrating a Cu-Fe-Si alloy with solid SiO2 and graphite under controlled CO partial pressure. The first-order and second-order interaction parameter of Fe on Si in molten Cu was determined to be -16 and 160, respectively. The negative value of the first-order interaction parameter clarified the addition of Fe to the Cu-Si alloy is effective in decreasing the activity of Si in the alloy.IntroductionIron-based materials have been commonly used for brake discs in high-speed trains. It becomes critical for brake disc materials to withstand high thermal loads with an increase in the maximum speed of high-speed trains. The fabrication of high heat-resistant, light-weight brake disc materials is then crucial for their use in next-generation high-speed trains. Carbon fiber is known to be a light-weight, high-strength material, and is considered to be a promising matrix material for use in brake discs. The Cu-Si alloy exhibits high thermal conductivity. The composite in which the Cu-Si alloy is added to the carbon fiber matrix is expected to be a high performance material for brake discs. The composite can be prepared by the infiltration of the Cu-Si alloy into the carbon fiber matrix at a temperature higher than 1700 K."

Jan 1, 2012

By M. H. Dehghanpoor, M. Zivdar, M. Torabi

"A hydrometallurgical route was developed to extract metals such as gold, silver, copper, and selenium from anode slime from Sarcheshmeh Copper Complex in Iran. For the extraction of copper by leaching, the anode slime was heated and stirred with 4 M sulphuric acid in the presence of oxygen. Optimal conditions for recovery of copper were temperature 80°C, mixing time 5 hours, and oxygen flow rate 2 L/min, resulting in a copper recovery of 94.47%. Silver and selenium were dissolved by leaching anode slime from which the copper had been removed with nitric acid. For gold extraction, anode slime was heated with aqua regia at 90°, and the gold then extracted with 2-ethyl-hexanol at a concentration of 0.5 M and phase ratio of 4. The extract was then stripped with soda solution at pH=10.5 and a phase ratio of 5. Finally, gold was recovered by precipitation with oxalic acid at a ratio of mass to volume 10 g/L. Total gold recovery was 80%. IntroductionDuring the electrorefining of copper, some metals are accumulated in the byproduct anode slime, which is an important source for recycling and recovery of these metals (Petkova, 1994). In this paper, a hydrometallurgical route is described for the recovery of precious metals from copper anode slime of Sarcheshmeh Copper Complex, which is located in southeastern Iran .Copper anode slime is black or gray powder with a particle size less than 200 mesh. Approximately 2 to 20 kg of anode slime is produced per ton of copper cathode. The slime is characterized by higher amount of Ag, Se, Pb, and Cu compared to other metals and a very low Au content (Khaleghi and Ghader, 2013).The copper anode slimes are composed of 11.69% selenium, 3.93% copper, 5.26% silver, 0.13% gold, and 45% barite, plus lead, tellurium, antimony, sulphur, and silica with small amounts of nickel, iron, zinc, and bismuth. Gold is one of the most important noble metals due to its wide applications in industry and economic importance, so recovery of gold from slime is more appealing than that of other metals. According to the World Gold Council (2013), the demand for gold has increased during the last decade. This increase is due not only to the increasing demands of the jewellery market, but also to the increasing demand for gold in industrial as well as medical applications (Ranjbar et al., 2014)."

Jan 1, 2016

By N. L. Wimmler

The Metaline mining district was examined in 1942 by Bureau of Mines engineers with the cooperation of geologists of the Federal Geological Survey. Because the demands of war production were rapidly depleting reserves in some of the older zinc-lead producing districts of the United States, it was decided that an attempt should be made to increase the proved or indicated ore reserves of the Metaline district. With this objective, certain areas to be explored by diamond drilling were selected. The Bureau of Mines began work on this program. January 15, 1943; work terminated September 8, 1945. Forty-five holes were drilled in seven areas, The holes ranged from 154 feet to 2,050 feet in length. Their combined length was 38,150 feet. Thirty-three of the holes were drilled in. the North Pend Oreille and the West Bella May areas.

Jan 1, 1949

By J Boshoff

The management and operation of tailings storage facilities (TSFs) are often neglected until the process plant has to shut down as a result of this negligence or as a result of a catastrophic failure as was the case during the recent TSF failure in North America.TSFs are often regarded as non-assets and do not receive the attention they deserve in terms of technical expertise and financial provision. A TSF is not a simple structure but a complex and dynamic structure that changes throughout its operational life. The operational life of a TSF is the period in which there is the greatest opportunity for risks to occur. The failure of a TSF is normally not as a result of a single event but as a result of a consequence of events. These events are often not recognised in time due to a number of factors.Process plants and slurry pumping systems are operated at suboptimal conditions in order to maintain throughput. At the same time, the tailings properties are compromised in terms of slurry density and particle size distribution amongst other things. Tailings deposition cycles and drying cycles are not well understood and the tailings management strategy is not well tuned in terms of maximising consolidation and improving in situ densities. Pond control is also neglected. These are aspects that form the keystone to the effective utilisation of available deposition area as well as the frequency and cost of future embankment raises.Apart from operational issues, forward planning in terms of budget requirements, increases in tailings throughput, embankment raises, pipe replacements, etc are normally put on the back burner. Available deposition space at the time seems to render this planning obsolete.The bottom line is that responsible tailings management and proper forward planning can limit liability and reduce the bottom line in terms of cents per ton if correctly implemented by suitably qualified tailings managers and engineers.The aspects that need to be considered as part of responsible tailings management are highlighted in this paper.CITATION:Boshoff, J, 2015. Responsible tailings management, in Proceedings Tailings and Mine Waste Management for the 21st Century , pp 317–322 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 27, 2015

By J. D. Ramsdell

The purpose of this investigation was to determine the effects of the impurities, oxygen, nitrogen, carbon, and iron (in low percentages) on the mechanical properties of electrolytic titanium. The strength and hardness of binary Ti-O, Ti-N, and Ti-C alloys are linear functions of alloy content in the composition range investigated. Compared to oxygen and carbon, nitro-gen is the most effective strengthener and hardener, followed by oxygen, then carbon. When the carbon concentration is above 0.10 percent, carbides are present, and strength and hardness are relatively unchanged. For equivalent hardness levels, Ti-Fe alloys are stronger than binary titanium alloys containing oxygen, nitrogen, or carbon. However, the strengthening is related to the presence of transformed beta in the structure.

Jan 1, 1960

By E. H. Myrhaug, K. Aasly, T. Malvik

Six different types of quartz and quartzites used as raw materials by ferroalloy plants have been investigated with respect to their thermo mechanical properties. In order to investigate the effect of the thermal shock caused by the rapid heating of quartz when it enters the furnace, the following techniques have been used for both in situ investigations and investigations of pre-heated quartz: -Heating stage microscopy for in situ observation of heating effects. -Shock heating of quartz in an induction furnace An optical microscope-mounted heating stage was used for in situ observations of the microscopic effects of heating up to 1300 ºC. The effects of heating were observed at different temperature intervals in different samples. The main temperature intervals were below 573 ºC and above 1000 ºC. The cause of the observed effects is interpreted as fluid inclusion decrepitation for T<573 °C and structural implications (micro cracks, grain boundaries and remaining fluid inclusions) at T>1200 °C. Shock heating of the samples was carried out in an induction furnace to 1300 ºC for ten minutes. The effects of the heating were studied with different techniques such as direct observation during and directly after heating, optical microscopy and XRD. Combined transmitted and fluorescence light microscopy shows that the heated quartz show an opening of the grain boundaries and evenly distributed micro cracks that were not present in the unheated reference samples. In some of the heated samples, weak generation of cristobalite was detected by XRD.

Jan 1, 2007

By A. O. Apata, F. V. Adams

The use of rice husk ash as aggregate for foundry sand mould production has been studied. 5 –25wt% rice husk ash was added to the sand mixture. The chemical, physical and mechanical properties measured include: chemical analysis of the rice husk ash, particle size, density, permeability, compatibility mouldability, moisture content, green compression and shear strength, dry compression and shear strength. The result revealed that, addition of rice husk ash to River Niger Silica sand, increased the mouldability, compatibility, grain fineness number, both green and dry strength, slightly decreased the density, permeability and moisture content. The result shows that better properties is achievable by the addition of rice husk ash to River Niger silica sand and can be used to enhance the mould properties of foundry sand.

Mar 1, 2017

By Mathias Woydt

The tribological and mechanical properties of binderless and metal-bonded niobium carbides (8 or 12 vol.-% of Cobalt, 12 vol.-% of Fe3Al) are presented. Rotating disks made of niobium carbide bearing hard metals were mated against alumina (99.7%) under unlubricated (dry) unidirectional sliding tests (0,1 m/s to 12,0 m/s; 22°C and 400°C) as well as in oscillation tests (f= 20 Hz, ?x= 0,2 mm, 2/50/98% rel. humidity, n= 105/106 cycles). Microstructure and phase compositions were determined as well. The tribological data obtained were benchmarked with different ceramics, cermets, hard metals and thermally sprayed coatings, where NbC bonded with 8% and 12% Co presented above 8 m/s the lowest wear rates so far in such a benchmark. Binderless NbC (HP-NbC1) and the metal bonded NbCs exhibited low wear rates under dry sliding associated with high P?V load carrying capacities. NbC-based hard metal bonded with 12 vol.-% of Fe3Al resulted in a higher hardness level than for 12 vol.-% cobalt. The tribological profile established revealed a strong position of NbC bearing materials under tribological considerations and for closed tribosystems against established reference tribo-couples.

Jul 31, 2018

By Kenneth L. Reid

The Mineral Resources Research Center at the University of Minnesota has recently installed a QEM*SEM system (Quantitative E.valuation of Materials using Scanning Electron Microscopy) to aid in detailed mineralogical evaluation of potential mineral resource developments in Minnesota and to provide services to the North American mineral industry. A primary application for the unit is to serve the Minnesota taconite industry by providing mineralogical analysis of ores and concentrator products. Minnesota taconite ores contain fine-grained magnetite in a quartz matrix. The ores undergo several size-reduction/magnetic-separation steps to produce a final concentrate with approximately 75% passing 325 mesh and containing about 5% gangue. The paper describes a typical taconite concentrator flowsheet and reports some preliminary results of the applications of QEM*SEM particle image maps and cumulative yield liberation data to samples from selected points in the concentrator circuit.

Jan 1, 1988

By I. Clauzier

"A new method of managing electricity to reduce costs andimprove profits is discussed. Before taking steps to better manage electricity, it is essential to understand the terms peak demand and energy and their effect on an electrical bill. Knowing how electricity is presently used in the plant is the important first step. This goes beyond knowing how much electricity is used at each time of day, the individual contribution of every plant process to the total plant load must be known. At this point, each process is ranked according to importance to production in order to identify possible savings opportunities. These improvements can then be implemented by simply improving operations or in some cases, through the use of an automatic control system. IntroductionIn today&apos;s competitive environment, controlling costs is becoming increasingly important. All costs associated with operation must be controlled in an effort to improve competitive position. Electricity is a cost component that can and should be managed.Although the term management can mean different things to different people, the intent is always the same: to make the best possible use of existing resources, whether labour, equipment or electricity.The simple approach to managing electricity presented in this paper consists of four steps.I. Understand Peak Demand and Energy. It is essential to understand the terms, peak demand and energy and their effect on your electrical bill.2. Know Your Present Electrical Use. The present use of electricity in the plant must be known. This goes beyond simply knowing how much is used at each time of day, to accurately knowing how each process is contributing to the total plant electrical load, and ultimately to the electrical bill.3. Identification of Savings Opportunities. With this information, energy savings opportunities for reducing the electrical bill and improving profits can be identified.4. Implementing Improvements. Having identified areas of potential savings, improvements can then be implemented in order of their significance. This could be a matter of simply improving operations, or in some eases may mean the use of an automatic control system.These four steps can result in significant dollar savings."

Jan 1, 1987