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By E. G. Kelly

This paper describes the performance of a modern compound trough profile spiral that is optimized for fine coal cleaning. Reduced performance (Tromp) curves are presented to compare these new spirals with older designs, as well as with other commonly used coal cleaning equipment. As an aid to equipment selection and circuit design, data are also presented to show how variables, such as flow rate, pulp density, and particle size affect efficiency and the separation specific gravity.

Jan 1, 1984

By Muriel S. Robinette

Ground-water contamination from uranium operations could be avoided with proper site analysis techniques. Contamination from tailings disposal sites is carried downgradient within permeable hydrostratigraphic units which can be located and delineated with a combination of drill holes, borehole geophysical logs and surface geophysics. Several case studies are presented to illustrate this application.

Jan 1, 1980

By Milka Madahana, John Ekoru

For efficient management of operations, mining companies are required to be able to predict potential scenarios for main market factors. Competitive advantage and value creation are established through managing the value chain well. The mining value chain is usually faced with challenges from various shifts in commodity markets as well as ongoing uncertainties. Therefore, there is a need for accurate analysis of data from the markets, for the prediction of commodities, for instance, Precious Group Metals (PGM). The main objective of this research work is to apply machine learning methodologies with the aim to identify patterns and trends in the Precious Group Metals, and thereafter analyze and predict the future trends of these markets. Numerous machine learning models are applied to a dataset consisting of 15 years of daily price for eight precious metals namely Platinum, Palladium, Rhodium, Ruthenium, Osmium, Indium, Silver, and Gold. The results reveal the patterns and trends within the data sets and that different machine learning methods could be suited for the prediction of market prices for each of the PGMs. The application of an amalgamation of various machine learning methods may result in more accurate predictions of the PGM markets. Accurate prediction of market prices for PGMs will possibly result in unlocking untapped sources of value in the mining industry.

Jun 25, 2023

By Adolf U. Honkala

Dundee Cement Company was incorporated in 1958. The equity capital for the venture was supplied by a Swiss firm called Holderbank Financier and a group of its principals. Holderbank Financier, a holding company, is a direct outgrowth of Holderbank Cement Company, a company founded in 1912 by the father of Dr Hans Gygi who is the president of Dundee Cement Company and a member of the Board of Holderbank Financier. From one plant in 1912 located in Zurich, Switzerland, Holderbank grew to its present size of 32 plants in 17 countries, having a capacity of 90 million barrels of cement per year. Dundee Cement Company constructed its first cement plant near the little town of Dundee, Michigan. This site was selected because there is an abundance of limestone and clay of the correct chemical composition for cement manufacture and the deposit was advantageously located near the large population centers of Detroit, Toledo, Cleveland, and Chicago. Construction of the 5. 5 million barrel, two kiln, plant was completed and the plant started up in the fall of 1959. After a year or two of the usual problems in a new plant and the expected difficulty of breaking into a nearly saturated market, Dundee began to prosper.

Jan 1, 1970

By C. Clark, R. Pakalnis, B. Seymour, L. Martin, M. Stepan, M. Roworth, C. Caceres

The National Institute for Occupational Safety and Health (NIOSH), Office of Mine Safety and Health, Ground Control Engineering Branch is investigating the use of shotcrete in weak rock mass mines with the objective of reducing fatalities and injuries resulting from rock fall accidents. When shotcrete is used as part of a multielement ground support system, there is a need to know the support characteristics that the shotcrete contributes to the overall system. To quantify the support provided by the shotcrete, flexural strength tests were conducted with two common, commercially available fiber-reinforced shotcrete (FRS) mixes using the round determinant panel (RDP) test method, ASTM C 1550. A portable RDP test machine developed by NIOSH researchers was used to determine the peak flexural load and residual load capacity for a steel FRS and a synthetic poly FRS that were sprayed using dry mix procedures and equipment. Besides the flexural strength and loading behavior determined from these tests, a method was also developed for measuring the width of cracks exposed on the underside of a shotcrete panel during a RDP test and relating these measurements to residual load values. Quantifying the peak flexural load and residual loads of a shotcrete mix through on site testing at a mine and visually assessing the loading cycle and load-carrying capability of the shotcrete applied to underground workings will improve mine safety by providing a better assessment of the stability of shotcrete supported entries.

Jan 1, 2010

By B. C. Lewis

The mining industry has experienced a general trend toward an increasing number of longwall operations, an increasing percentage of underground coal being mined by longwalls, and increasing productivity from the longwalls. Longwall operators have not yet reached a state of mining euphoria. Competitiveness both within the industry and from alternate fuel sources is forcing continued pursuit of higher productivities and lower costs. The following graphics present trends in the industry. Longwall mines, as defined for this presentation, are those reportedly having longwall installations in each of the respective years. Production from both the continuous miner and longwall units is included in the longwall mines. Non-Longwall mines are all other underground mines. Productivity calculations are based on total employee-hours associated with the operation.

Jan 1, 1990

By C. E. "Sam" Lovewell

In approaching a discussion of production of cement, I hope I won't be like the porter in the bank who was asked if he could give some details on the rediscount rate. He replied, "Boss, when I said hello, I told you all I know." Need for change every so often is illustrated by the story of the little boy four years old who had not spoken a word in those four years. One morning he said, "This damned oat meal is burned'." His Dad was amazed and said, "Son, how come you haven't said a word for four years and now out of a clear, blue sky you say, "The oat meal is burned." Johnny said, "Well, up to now everything has been all right." Not being a mining engineer myself, and my subject not dealing with mining engineering directly, I can only hope that you will agree that the subject has current relevancy by the feet that it can materially improve our environment by putting to good use a potential environmental polluter; namely, fly ash. The profitable utilization of fly ash can reduce cost of use of coal as an energy source. Therefore, it behooves us all to explore to the greatest depth, the pluses and minuses occasioned by its use wherever possible. My particular subject and my particular interest lie in its utilization as a blend in the production of Type IP Portland-Pozzolan Cement meeting requirements of ASTM C-595, Type IP.

Jan 1, 1974

By Andrea Biagi, Elisa Comis, Gianluca Bella, Enrico De Panicis, Guido Barbieri, Matteo Giani

The Sotra Link Project is a major infrastructure project in Norway involving the design, construction, financing and maintenance of several underground and surface structures between Sotra island and the city of Bergen, among them 23 tunnel portals, 12.5 km of tunnels and a 900 m long suspension bridge. This paper describes the benefits in applying a Building Information Modelling (BIM) approach to tunnelling, from Early Design to the Detail Design Phase. The BIM application to the Sotra Link Project resulted in several improvements, such as efficient handling of clashes and inconsistencies, deeper understanding of effective design choices (reduction of errors), more efficient communication between designers, enhanced control of project quantities and costs. The advantages of the BIM approach during the ongoing Construction Phase are also explained.

Jun 23, 2024

By Richard J. Goff

Technical Support, one of several major organizational units in the Mine Safety and Health Administration, provides technical assistance to the mining community in all areas of health and safety. One of its many areas of expertise is noise control. Depending upon the needs of the operator or inspector, the services provided can range from locating major noise sources to actually building noise controls. Over the years a vast amount of knowledge has been obtained as to what will work and what will not. DESIGN GOALS While many noise controls have been developed for mining equipment and operations, the most acceptable (ergo successful) have achieved the following design goals: - a noise level reduction of at least 5 decibels; - minimum interference with production; - inexpensive to install; and - effective in reducing low frequency noise.

Jan 1, 1984

By L. B. Gittinger

Mr, Chairman, members- and guests of the AIMS, I greatly appreciate this opportunity to speak before you. I hope this is just the beginning of a long and mutually beneficial relationship. This winter I decided to join the other 36 Freeporters who belong to the AIME; and, I applied for membership in the Society of Mining Engineers. To queries as to my interests in the Society, I had this answer: our principal challenge -- more so today, than at any time in my nearly 25 years in the industry -- is discovery and development of new sources of raw materials. I want to join you in meeting this challenge.

Jan 1, 1966

By Casandra Gamez Gonzales, Angelina Anani

Copper, the newest addition to the critical mineral list, is an essential metal whose electrical and heat conductive properties label it as a vital mineral for the creation of renewable energy sources and the reduction of Greenhouse Gases (GHGs). However, despite copper’s leading role in the transition to sustainable energy and mining practices, the mining industry has faced various battles in the extraction of this valuable material. These challenges are based on mining’s negative reputation and extensive impact on the environment, nearby communities, and human rights. To ensure the survival of mining in the future and achieve mineral demands, an emerging topic that has initiated the revolution of the traditional sector into a more environment- friendly and transparent industry, is Environmental, Social, and corporate Governance (ESG). ESG has motivated companies to seek growth opportunities and standardize risk accountability and transparency based on its collective framework that creates, modifies, and implements local, national, and international standards. These standards focus on improving environmental, social, and governance issues faced by companies and their projects. ESG has served as a guideline that investors utilize to assess companies and promote sustainability, responsibility, and disclosure to create positive and balanced relationships with stakeholders and the environment. Nonetheless, concerns have been rising which state that ESG is negatively impacting the mining industry by targeting what fuels the industry and world: ore deposits and their resources. Therefore, this research focused on answering the following research questions: what are the impacts of ESG on the copper supply chain and how will stricter ESG standards affect future copper production?

Feb 1, 2024

By William H. Wiese

Anecdotal reports of high rates of congenital malformations and spontaneous abortions at the Shiprock Indian Health Service Hospital in San Juan County, New Mexico prompted an interview survey, obtaining data from families of 26 former uranium miners and 30 controls. Results supported the possibility of increased fetal wastage and congenital malformations. However, definitive conclusions were obviated by methodologic limitations in terms of selection of cases and controls and interviewing technique, as well as very low numbers and lack of statistical significance. The Council of Environmental Quality (1980) published a report which singled out San Juan County, nationally, as having an extra-ordinary high rate of congenital anomalies reported from birth certificates in the years 1973-75. San Juan County is in the northwest corner of New Mexico and includes the northeastern edge of the Navajo Indian Reservation. It has been the site of uranium mining and milling and also of coal mining (Clement Associates, 1980). While much attention has been focused on lung cancer and chronic lung disease as health hazards to uranium miners, virtually no attention has been focused upon possible reproductive effects that may result from exposure to radiation. Could these reports indicate such an additional arena of health effect either on miners or on others living in the vicinity of the mines and mills? The biologic and epidemiologic literature does not lend much support for adverse genetic outcome. The UNSCEAR report (UNSCEAR, 1977) summarizes much of the existing data. For example, on the basis of many animal studies and what has been observed in atom bomb survivers in Japan, it has been estimated that mutation rates resulting from low LET radiation to paternal germ cells would be 60 X 10-6 recessive and 20 X 10-6 dominant mutations per gamete per rad. There would be a five-fold increase in the number of recognizable abortions. The doubling dose for genetic disorders in mice is estimated at 100 rads. The assumption has been that low levels of exposure, such as might be received occupationally from uranium mines and mills or environmentally will produce reproductive effects that would defy distinction from background rates. However, the possibility can not be dismissed. In man, spermatogonia are thought to be three-fold more sensitive than in the mouse. Also, the high LET radiation from alpha particles is as much as 20-fold more effective in inducing changes in meiotic and post meiotic stages of cells, compared with low LET radiation. There is some degree of localization of alpha emitters in testicular tissue after inhalation of radon and radon daughters (Blanchard, R.L. and Moore, J.B., 1971; Pohl, E., 1964). The slopes of doseeffect curves are affected by type radiation and rate of administration. Data on such curves are poorly defined and debated as to whether there may be increased or decreased effect per unit dose at low levels of high LET radiation. Increased rates of aberrations of chromosomes in peripheral lymphocytes cultured from uranium miners have been reported (Brandom, W.F., et al., 1978). At cumulative exposures of 100 working level months (WLM) or less, a range of exposure lower than the limit of current occupational standards, the aberrations were increased more than two-fold. Our interest has led us to pursue the question of reproductive effects along three separate paths of inquiry: studies of the secondary sex ratio, cytogenetic study of human sperm, and studies of rates of congenital anomalies. I will present the thrust of our findings, most of which remain preliminary, comment on their interpretation and limitations, and indicate directions needed for future research. The secondary sex ratio is the ratio of males to females at birth. In the U.S., the ratio averages around 1.05. Ratios in blacks are somewhat lower (1.025) than in whites (1.053). For American Indians, the data are less definite. Values from Oklahoma and California are similar to whites (1.05). Southwestern tribes have, as we shall see, varying levels. The theoretical effects on sex ratio resulting from irradiation of the zygote are based on the principles of sex-linked genetics, including differential effects of lethal dominant and recessive mutations on the sex chromosomes, complicated by possible non-disjunctional events. Observations have done little to clarify, confirm or refute the theories. The sex ratio of progeny of survivers of the atomic bomb showed little change (Schull, W.J., Otake, M., and Neel, J.V., 1981). Observations in children of uranium miners having been inconsistent. Most frequently cited is a study of miners in Czechoslovakia (Müller, C., Razicka, L., and Bakstein, J., 1967). Compared with children born to miners prior to the start of mining, the sex ratios of children born after the start of mining were decreased -statistically significant after correcting for birth order. The ratios in first-born children were, before the start of mining, 1.118, and, after the start of mining, .713. In the interview survey at Shiprock, the sex ratio in families of non-miners was 1.03, and in families of miners it was 0.73 (p < .05). Dr. Alan Goodman at the University of New Mexico has studied trends in the sex ratio in the general population in New Mexico and Arizona with particular reference to counties in the Four Corners area and the Navajo Indian Reservation, areas where uranium mining has been active_ His findings (unpublished) are as follows: (1) Beginning in the early 1950&apos;s, there has been a modest, but persistant and statistically significant decline in the secondary sex ratio for the state of New Mexico compared with the U.S., a decline that roughly parallels the emergence of uranium mining in the Grants mineral belt in northwestern New Mexico. (2) Data available for the 11 years since 1969 show that among the five counties with ratios significantly lower than the state

Jan 1, 1981

By Bryan Ulrich

Knight Piésold?s annual roundtable discussion was held at the Red Lion Hotel and Casino in Elko, NV on March 14. This year the title was, ?Roundtable discussion on material co-disposal/ co-placement in the mining industry.? This topic was chosen because of the benefits that the mining industry could realize through the advancement of improved methods of storing tailings and mine waste and from reducing short-and long-term environmental hazards while reducing the footprint of these facilities and making strides toward attaining a walk-away solution. Knight Piésold had a local representative, Bryan Ulrich, as well as representatives from its Denver, CO office, including Tom Kerr, president of Knight Piésold?s U.S. practice, and Jeff Coffin, Ph.D., geotechnical engineer, to help facilitate the discussion. The event played host to about two dozen attendees from several western states. Attendees included personnel from more than 10 mining properties, various corporate offices and academia. The purpose of the roundtable was to exchange ideas and information pertaining to broad topics revolving around the subject of co-disposal/co-placement in the mining industry. Compared with traditional conferences and symposia, the roundtable forum tends to provide a less inhibited format for discussion. In the roundtable format, lively discussions and applicable tangential departures are encouraged. This was the seventh in the series of the Elko Roundtable events. Previous roundtables pertained to: ? Heap leach pad design, construction and operation. ? Design, construction and operation of tailings storage facilities. ? Site-wide water considerations. ? Mine closure and cover design. ? Strides toward sustainability in mining. ? High-density tailings, paste and filtered tailings. Acid rock drainage for engineers and environmental scientists.

Nov 1, 2013

By Nikhil Dhawan, Sanjay Pindar

The limited lifespan, ever-growing demand, and significant lithium and cobalt content are responsible factors for the immediate recycling of discarded lithium-ion batteries. Discharged batteries were dismantled, segregated, and size reduced to recover cathode and anode material. The active cathode material comprises LiCoO2 (65.8%) and LiMn2O4 (34.2%) and was carbothermal reduced with recovered graphite in a microwave furnace followed by water leaching and magnetic separation. A Box Behnken statistical experimental design is used for process optimization. Both cobalt and manganese report to magnetic fraction, whereas graphite and lithium carbonate report to non-magnetic fraction and solution crystal respectively. The final product comprises of cobalt 73% and manganese of 14% with process yield of 36% and saturation magnetization of 76 emu/g.

May 16, 2020

By M. Westerstrand

It is known that the water chemistry of the process water during ore refinement can affect product quality, such as iron pellet strength. The main objective of this study was to quantify the amounts of major elements, such as Ca, Mg, Na, S and Cl carried by process water and by magnetite grain surfaces to the end product, iron ore pellets made from magnetite ore from the Kiirunavaara Mine in northern Sweden. In addition, the amount of colloids (0.22µm ? 1kD) in the process water was examined by ultrafiltration. The amounts of various elements sorbed to the magnetite surfaces were estimated by leaching with Milli-Q water, MgCl2, NH4-acetate and Na-acetate. Total dissolved solids were between 1,446 and 1,775 mg/l, dominated by Ca, S, Na and Cl (89%). The colloidal fraction was less than 3% for major ions. For Ca and Mg, sorption to magnetite surfaces was a much more important transport mechanism for the pelletizing process than evaporated process water, but for Na, Cl and S process water was an important carrier.

Jan 1, 2010

By R. V. Ramani, S. Shankar

The phenomenon of re-entrainment is seen in environments such as sand dune formation, soil erosion, fugitive dust emission and the spread of radionuclides from accidents involving nuclear weapons. A thorough review of existing literature reveals that work on re-entrainment of dust in mine atmospheres is scant. The present study was undertaken as a part of ongoing research at the Generic Mineral Technology Center on Respirable Dust at the Pennsylvania State University on the development of methods to predict ambient dust concentrations in mine atmospheres (Ramani, 1983). The contribution of re-entrainment to the spatial and temporal concentration of dust in mine airways is being studied. The research has included wind tunnel and in-mine studies. A set of seven experiments was performed under controlled conditions in the US Bureau of Mines&apos; Lake Lynn Laboratory mine. Two types of source coal dust, anthracite and bituminous, were subjected to various airflow rates and were subjected to walking by two different individuals. Six sets of instruments were used along the test section for sampling airborne particles. The average air velocity just above the coal dust bed varied between 2.1 to 3.2 m/sec. Due to re-entrainment as a result of the airflow conditions, the average respirable dust concentration in the center of the mine airway increased to 0.09 mg/m3 (standard deviation = 0.03 mg/m3) from an initial value of 0.02 mg/m3. The concentration of all (total) airborne dust increased to 0.17 mg/m3 (standard deviation = 0. 10 mg/M3) from an initial value of 0. 02 mg/m3. The action of people walking, however, caused higher amounts of re-entrainment. The average concentration of respirable and total dust at the center of the mine airway increased to values of 0. 28 mg/m3 (standard deviation of 0.12 mg/m3) and 1.53 mg/m3 (standard deviation of 1.0 mg/m3), from initial values of 0.03 and 0.05 mg/m3, respectively. It was observed that the dust concentrations were much higher near the floor, immediately at the end of the coal-dust bed. Depending on the level of activity and the amount of dust deposited in the mine airways, re-entrainment may become an important source of airborne dust in areas away from the point of actual mining.

Jan 1, 1996

By Ryan Dr.

In December 1988 Phelps dodge corporation brought an underground gold mine into production in the republic of Botswana. The mineralization is associated with steeply dipping shear zones in Archean greenstones of the Tati Schist Belt. The gold is intimately associated with sulfides and is refractory in nature. The deposit is being exploited by underhand open stoping methods. Vertical and inclined shafts are used to hoist the ore to surface where it is treated by conventional crushing, milling and flotation, followed by fluid bed roasting with CIP elution and carbon regeneration. Adjacent deposits are being explored with a view to increasing production. Legal and taxation aspects of operating in Botswana are discussed.

Jan 1, 1989

By R. G. Reddy

Viscosities of Feo-SiO2 slags were calculated using the previously developed structural based model. An expression was derived using hole theory and the atomic pair model to relate the NO0 and temperature to the viscosity. The deduced equation n=4.9x10-9 T1/2 NO0 exp (E/RT) poise was successfully applied to predict the viscosity of FeO-SiO2 slags in the composition range of 0.1 < XSiO2 < 1 for several temperatures. The calculated data agrees well with the experimental viscosity data.

Jan 1, 1991

By Andrew R. Thomas

As the demand for most industrial minerals on the world market continues to climb, educational institutions maintain traditional policy in emphasizing chiefly metallic ore deposits and energy resources in addition to the general disciplines. In spite of their increasing importance, few universities exhibit great depth with respect to industrial minerals courses due to the shortage of specialized faculty in a category this broad. As new ideas are formulated and technological advances are developed in the field of industrial minerals, the classroom still exists as a student&apos;s primary source of information. This opportunity to give today&apos;s students the benefit of modern developements has not been utilized to its utmost potential.

Jan 1, 1981

By R. K. Mehta

Stirred ball mill feed used for ultra-fine grinding application requires fine size separation step in order to avoid over-grinding. This paper presents the selectivity curves obtained for oil shale and complex sulfide are using 460 mesh (30 micron) Derrick vibrating screen. Interestingly, the selectivity curves generated from the experimental data were monotonic increasing selectivity for oil shale but not monotonic increasing for sulfide ore. These non-monotonic increasing selectivity curves were similar to the mechanical air separator fishhook selectivity curves described by Luckie and Austin. A 2 stage classification in series model describing the fishhook selectivity curve has been used in proposing the classification mechanism for fine vibrating screens when heterogeneous multicomponent sulfide are undergoes size separation.

Jan 1, 1992