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By Bernhard Schwab

A popular rule in the mining industry is that a property should only be developed if average unit production cost is less than a given proportion of the estimated long-run price of the mineral. This paper provides a comparative analysis of the average cost approach (ACA) with the use of net present value (NPV) as an investment criterion. It is concluded that the ACA is an easily understood and easily applied rule of thumb which may serve as a rough first screening device, for example in the early stages of deposit exploration. Its operational convenience is at the expense of accuracy and validity, and the NPV provides a sounder method of making decisions, especially in the case of marginal deposits.

Jan 1, 1978

By J. Douglas Causey

No mines are active in the Hunter Mountain Wilderness Study Area (WSA), and no mineral resources have been identified in the WSA. However, the Monarch Mine has low potential for silver, copper, tungsten, and gold resources in quartz veins; the Shirley Ann Group and Sal Group have moderate and low potential, respectively, for silver, lead, and copper resources in skarn; claims overlying the Eureka Quartzite have low potential for silica resources; and the Tourmaline N1-4 Prospect has low potential for tourmaline resources in quartz monzonite. Copper, lead, silver, tungsten, molybdenum, wollastonite and garnet occur in skarn zones between monzonitic and carbonate units. Silver, tungsten, and copper also occur in quartz veins within monzonite. Known metallic mineral deposits are small, erratic and discontinuous. The J. 0. Mine, adjacent to the northeast corner of the WSA, may contain as much as 26 million tons of subeconomic wollastonite resources. The crest of an open pit to produce that resource would extend into the WSA. No information exists on geothermal potential because no exploration has been done in the area. No occurrences of energy minerals are known within the WSA.

Jan 1, 1983

By Donald Giroux

This report documents the design, fabrication, testing, and coal mine demonstration of a hopper-feeder-bolter during a four-phase program for the U.S. Bureau of Mines. The machine was designed to increase productivity and safety in under-ground room-and-pillar mining. It performed well as a hopper-feeder for continuous haulage during a coal mine demonstration. Testing in a simulated mine showed that the machine also has good roof bolting capability.

Jan 1, 1987

By PETER ROBINSON, KEVIN BARBER, OLIVER WHATNALL

Investigation and uptake of filtered tailings continues to grow throughout the globe. This is driven by a wide range of site-specific considerations, which include such factors as tailings characteristics (e.g., amenability to filtration), production rates, climate, water availability, cost drivers, environmental requirements, and social factors. Despite the aforementioned technological growth, the currently available filtration technology is not able to meet the needs of many operations and projects that would otherwise adopt the technology. Experience with large-scale industrial filtration shows that vacuum belt filter systems meet the needs of many modern users, exceptions being the inability to effectively dewater tailings at altitude and/or with a fine particle size distribution: a potential fatal flaw. This paper presents a case study on the utilization of the patented Viper Filtration technology on gold tailings to overcome this challenge and shares the resultant full-scale plant design, highlighting the features designed to overcome cost and scalability deterrents. This technology is a novel mechanical process which complements the vacuum pressure in dewatering the filter cake as it travels along the belt filter. This project commenced with a pilot testing program, which successfully met the objective to rigorously test, measure and record any performance improvements achieved when engaging the Viper technology. Of the two tailings products tested, gross improvements of 4.2%w/w and 5.7%w/w were achieved when compared to the conventional vacuum belt filter operation. This pilot testing facilitated measurement of operating and design data, which forms the basis of the full-scale system design and resultant equipment supply of three vibration roller assemblies for retro-fitting on the existing vacuum belt filter.

Jan 25, 2021

By E. V. Potter

"INTRODUCTION The oscillator and amplifier system described in this paper was developed specifically for driving sound generators of the type developed by H. W. St. Clair and described by him in an article 3/ published several years ago in the Review of Scientific Instruments.Nevertheless, with little or no alteration it can be used to drive any vibrating system in which the vibrating member must be driven at its resonant frequency; the only restrictions are that the driving mechanism be electrical in nature and that the vibrating member be accessible so that some type of pick-up can be coupled to it. Operation of the automatic frequency-control element in the oscillator, however, depends entirely on the operating characteristics of the vibrating member; therefore, in order to completely explain the operation of the circuit, it will be necessary to describe the construction and operation of the vibrator used with it. Only the essential features and characteristics of the vibrator will be described in this article, and the reader is referred to St. Clair's 4/ report for further details."

May 1, 1943

By S. Banisi, A. Haji-Zadeh, A. R. Hasankhoei, M. Maleki-Moghaddam

At the concentration plant of the Gol-E-Gohar Iron Ore Company (Iran) three 9m × 2.05m AG (Autogenous) mills (fixed speed) are used in parallel in a dry operation. The test works conducted in a scale down mill with a diameter of 1m indicated that conventionally used "deflector" type liners did not provide efficient environment for grinding. In this research, to improve the grinding efficiency, a new design using low profile end liners incorporating radial ribs of proper height was investigated. In order to determine an appropriate liner design at different operating conditions, a 100cm×10.8cm model mill was used for experimentation. The special design of model mill made it possible to increase the radial ribs height in steps of 6mm up to 18.5mm. The transparent end of the mill enabled accurate trajectory determination by image analysis. The results indicated that the new lower height profile deflectors and 15.5mm-height (14.5cm in industrial scale) radial ribs improved the mill performance while avoiding excessive pressure drop across the mill and wear on the liner. The image analysis showed that the use of new liners increased the distribution of coarse particles across the mill cross section from 28% to 35%. A new liner design was proposed by decreasing the number of liners in each slice from 5 to 4 pieces. The thickness of the inner head liners reduced from 45cm to 30cm and the outer deflector liners replaced by radial ribs. The distance between the feed and discharge inner head liners increased from the original 115cm to 145cm which increased the effective length of the mill by 26%. The new design reduced the weight and volume of end liners by 9% and 23%, respectively. It was predicted that the new liners design increases the mill throughput by 10% and reduces the metal consumption by 20%.

Jan 1, 2016

By K. Turgeon, J. -F. Boulanger, L. Whitty-Léveille, C. Bazin

"Several companies targeting Rare Earth Elements (REE) around the world have completed a Preliminary Economic Assessment showing positive project financial results. Although REE ores may contain high REE value, financing these projects remains difficult in part due to the number of processes required to valorize the elements and the relatively low yield of these processes. Direct ore leaching without the production of a concentrate may reduce the capital and some operating expenditures through process simplification, and increase revenues because of REE recovery improvement.A silicate REE ore is used to test various hypotheses regarding whole ore processing and to develop a simplified flowsheet. An atmospheric leach (200 kg/t H2SO4) of crushed whole-ore containing 0,6% REE, followed by impurity removal and REE precipitation recovers 80% of the REEs in a solution containing REE and Th. The high value contained in most REE deposits makes whole-ore approaches worth considering for most projects, given the losses of valuable species typically associated with the production of a REE mineral concentrate from the ore. INTRODUCTIONRare Earth Elements (REE) find applications in modern and clean technologies, whether civil, industrial or military. With China producing more than 90% of the world’s REE, the embargo imposed by this country in early 2010 increased REE prices for a three year period. With prices having shrunk back many-fold from their peak value, projects put forward during the hike are struggling to secure financing. Owing in part to unconventional processes such as acid-baking and solvent extraction, REE plants are high capital cost and high operating-cost units, and present technological risks (Verbaan et al., 2014)."

Jan 1, 2016

Pictured on these pages are the six RMCMI Scholarship Award Winners for the 1988-89 year followed by a brief profile. All winners were present as guests of the Institute at the June convention in Durango, Colorado to receive recognition at the Welcome Session Monday, June 26, 1989. Each state vice president served as the host for the collegiate winner. In addition to receiving a plaque from the Scholarship Chairman, Keith McGinnis, each winner receives $500.00 tuition credit for the coming academic year. As this is a continuing award, the winners from the previous year will receive another $500.00 for tuition credit in their senior year if they have maintained good academic standing and have been recommended by their university. Criteria for these awards to be made in the spring annually is (1) That the award be made to a sophomore student and used as tuition during the junior year. (2) That the recipient be both a U.S. citizen and a resident of the state involved. (3) That the recipient have good academic standing, be pursuing a degree in a mining related field and have an expressed interest in Western coal as a possible career path. The scholarship program includes curricula other than those in the mining departments, but in the engineering disciplines, such as geology, mineral processing and metallurgy. Contributions to this worthy project are tax deductible to each individual RMCMI member or his firm. Through annual donations of $100.00 or more, the Patrons of the Institute fund the scholarship program and the various vice presidents contribute the travel expenses to convention for these outstanding young collegiates. Donations to this worthwhile program may be made payable to RMCMI Scholarship and mailed to the RMCMI Office, 2700 Youngfield Street, Suite 100, Lakewood, CO 80215. Profiles of the 1989 Scholarship Winners follow. [ ] David P. Pelletier University of Arizona Tucson, Arizona David is a Mining Engineering major and graduated from Santa Fe High School in 1981. He served in the Sixth Marine Regiment, Second Marine Division of the United States Marine Corps from December 1982 thru December 1985. He is a student member of SME-AIME and has held the offices of treasurer, vice president and president. He works volunteer shifts at the University of Arizona San Xavier Mining Laboratory [ ] Johnny F. Blizzard Colorado School of Mines Golden, Colorado A high school graduate of Longmont, Colorado, Johnny carries a 3.968/4.000 at Mines, majoring in Mining Engineering with a minor in Metallurgy. His name has appeared on the Academic Dean's list for the past two years. He received the Robert M. & George R. Harris Scholarship during this past year. He is a student member of SME-AIMMP and an executive council member of CSM's chapter of AIME. Summertimes, Johnny works as a miner for Edger Mine in Idaho Springs, CO on an experimental project for USBM.

Jan 1, 1989

Australian continental crust has accreted and consolidated by thirds: 1/3 during Archean time, 1/3 during Early to mid- Proterozoic time, and 1/3 during latest Precambrian to mostly Paleozoic time. The progression of orogenic systems and the crustal consolidations they represent seem not fundamentally different in basic orogenic processes from better known Mesozoic-Cenozoic examples in that accretionary, continental margin, collisional, and intraplate intracratonic inverted and/or reactivated systems are all recognizable in the tectonic evolution of Australia.

Jan 1, 1995

By Ronald C. W. Webber‑Youngman, Philani Larrance Ngwenyama

Entrapments are a huge risk in underground mines. This happens when miners (or any other persons who have entered underground) survive the initial event of an accident, become trapped or lost in unknown and life-threatening locations after evacuation, and remain unaccounted for. At this point, every second counts, and emergency response is highly desired for any chances of saving survivors. The survival chances of the missing persons depend on how quickly they can be located. Rescue teams are often deployed to search for the missing persons underground. However, the rescue teams are forced to search in random and presumed areas of the mine. This is due to the unavailability of information pertaining to the whereabouts of the missing persons. Not only the provision of accurate locations, but various other types of information such as post-accident two-way communication can enhance the survival chances of the missing persons. This information can be provided by a fit-for-purpose missing person locator system. A wide variety of missing person locator systems are already commercially available, some are in testing phases and others in prototype and development phases. This includes tracking, tracing, location detectors and post-accident two-way communication systems. These systems have unique functionalities, capabilities and limitations; making it difficult for mines to select the most effective, applicable and suitable system specific to their mine. In this study, the user requirements for a fit-for-purpose missing person locator system were developed. The purpose of the user requirements was to provide a guideline to facilitate the system selection process. The user requirements can also be used as a tool to measure and evaluate the performance of the selected missing person locator system. The user requirements were also used to predict the success of the selected system under different missing person incident scenarios. The development of the user requirements showed a potential for many other benefits for missing person locator systems.

Nov 2, 2023

By F. C. Harris, S. J. Gaab, J. Sattarvand, S. Duzgun

Underground mines are inherently dangerous due to potential hazards such as fires, explosions, and caving of rock. Although these events are rare, once they occur a speedy and safe egress of mineworkers is critical to survival. Static evacuation systems use exit signs or directional lines but can get obstructed or be hardly visible in smoky or dusty conditions. This paper presents the investigation of the effectiveness of a smart evacuation technology in underground mining, where a real-time guidance system leads individuals on an optimised path to the egress while avoiding danger zones, compared to conventional practices. Participants simulated an evacuation from a virtual reality mine, using the conventional system and the smart evacuation system with real-time guidance. The highest reduction in evacuation time using the smart method amounted to nearly 40% on average. Moreover, 83% of participants preferred the smart guidance system, and agreed that it could enhance safety.

Sep 1, 2021

By Hsin Wei Wu

A real-time Diesel Particulate Matter (DPM) monitor has been developed on the basis of the successful National Institute of Occupational Health and Safety (NIOSH) designed Personal Dust Monitor (PDM) unit. The objectives of a recently completed Australian Coal Association Research Program (ACARP) study were to modify the PDM to measure the submicrometre fraction of the aerosol in a real-time monitoring underground instrument. Mine testing focused on use of the monitor in engineering evaluations to determine how conditions can be improved. Studies, including a selection during Longwall (LW) moves as described in this paper, demonstrated how DPM concentrations from vehicles fluctuate under varying ventilation and operational conditions. Correlation between the current SKC DPM measurement system and real-time DPM monitors were conducted and results from six mines show a correlation between elemental carbon (EC) and the new monitor DPM mass ranging from .51 to .81 with R2 >.90. These differences are suspected to be due to variations from mine to mine in aspects such as mine atmospheric contamination, vehicle fleet variations, fuel type, engine maintenance, engine combustion efficiency, engine behaviour or interference from other submicrometre aerosol. Real-time monitoring readily reflects the movement of individual diesel vehicles and allows pin-pointing of high exposure zones such as those encountered where various vehicles work in areas of constrained or difficult ventilation. DPM monitoring approaches that have been available for some time based on shift average monitoring do not readily allow successful engineering evaluation exercises to determine acceptability of pollution levels. Identification of high DPM concentration zones allows efficient modification of mine ventilation, operator positioning and other work practices t o reduce miners? exposures without waiting for laboratory analysis results.

Jan 1, 2010

By Michael R. Brown

A facilities success or failure of doing well during a regulatory inspection is typically measured by the number and type of citations that result, and financial liability resulting from those citations. The success of a facility during an inspection depends on several factors including, the preparation prior to an inspection, behavior and activities during and inspection, and finally, action taken following the inspection. This paper contains suggestions for improving inspection results and establishing an attitude of compliance at manufacturing and mining facilities.

May 1, 2002

By Deborah A. Kopsick

Several minerals were observed and collected in a small gully originating from a weathered coal processing waste (gob) pile in Barton County, Missouri. The rapid alteration of these various minerals after collection suggested that they might represent a dehydration sequence. X-ray diffraction of the dehydrated and rehydrated minerals deposited on the gob pile indicated the presence of the monohydrate and heptahydrate forms of ferrous sulfate, szomolnokite and melanterite respectively. The occurrence of melanterite (FeSO4.7H2O), was limited to isolated areas of ponded water while szomolnokite (FeSO4.H2O), was associated with the outwash areas of the pile. Laboratory dehydration of melanterite collected at the gob pile revealed the formation of rozenite (FeSO4.4H2O), an intermediate form of ferrous sulfate. Szomolnokite was shown to be the stable form of these ferrous sulfates during these experiments while melanterite and rozenite were shown to alter readily. Chemical analysis of szomolnokite revealed enrichment in Fe, Mg, Zn, Cd, Cu and Mn relative to the chemical composition of the gob ad the lechate generated from the gob wastes. Although this gob pile had been weathering for more than 35 years, significant concentrations of trace metals were still being released from the pile through the generation of leachate and the formation of various soluble metal enriched ferrous sulfate minerals.

Jan 1, 1982

By Gilbert Soler

PRODUCERS of alloy steels recognize the importance of chemical composition in rela-tion to the hot-working properties and the typical surface defects found in their prod-uct. Each analysis of steel has its own peculiar characteristics. Under conditions of standard mill practice each analysis is susceptible to certain types of defects. Mill practice must be varied to obtain the best combination of surface and internal quality in the product. Chemical composition influences the cast structure and crystallization character-istics of the ingot. It also determines the rate of heating and cooling, the plastic hot-working range, and the phase structure of the steel at various temperatures as well as the tendency toward scale formation and decarburization, This paper endeavors to emphasize the manner in which chemical composition affects the various properties of steel, and to indicate the relative impor-tance of these factors in relation to the hot-working properties and surface charac-teristics of killed steel. The influence of chemical composition may be outlined as follows: I. Effect on the cast structure of steel, including: A. State of deoxidation, and type of inclusions. B. Gas content of steel. C. Freezing point and melting point of steel.

Jan 1, 1940

By Cabrera M. Manuel C

A fines de 1980, la empresa Minero Perú construyó una operación piloto de monitores y planta de lavado con una capacidad de 1,500 m3/día, incrementando la producción de oro a un 80%. En este sentido, el presente texto señala la producción de oro de esta minera peruana, utilizando dichas herramientas mencionadas. Para ello, se describe la geología, minado, características del monitor seleccionado, características de la bomba de alta presión, metalurgia y las plantas de lavado.

Oct 14, 1980

By H. R. Banks

"AbstractThe rod mill introduced into the Sullivan Concentrator flow in September, 1948, replaced two sets of 74 in. by 20 in. rolls and their accompanying screens. In addition to the work formerly done by the rolls, the rod mill is producing a finer product and one which provides more suitable feed for the primary ball mills. The object of the finer discharge from the •primary mills is to make possible a feed directly from the mills to a series of flotation machines where a large portion of the galena can be withdrawn from the circuit while the galena is still coarsely granular. The interposing of classifiers between grinding and flotation means the selective grinding of the galena.The author summarizes the work of •the rod mill through the first 5,000,000 tons and shows that the wear of lifters, liners, and rods is definitely below normal for the type and size of rock being handled. The rod mill, driven through a fluid coupling, has been subject to a range of speeds from 13.5 to 19. A pinion in the speed reducer was changed to allow the extending of the normal speed range of the fluid drive of approximately 4 r.p.m.Since the critical speed inside the liners •is 23.4, the range •in per cent of criticial is 57.7 to 81.2 per cent.The capacity of the mill increases with increasing speed but the character of the product remains approximately the same except when the feed rate is too high.Consumption of steel, power, and other operating data are presented.The author introduces certain fundamental observations on the principles involved •in comminution in order to support the special design and operation of the rod mill."

Jan 1, 1952

By Tom Snyder, John Brulia

Part 4 is the final article by the authors on hazardous materials (HM)transportation safety and compliance for U.S. shippers and carriers who offer and transport commercial explosives in commerce on public highways. This article covers hazardous materials (HM) cargo segregation and securement of non-bulk packaged explosives.

Jan 1, 2015

By Jeremy Fletcher

In today’s world, the requirement of Steel Producers to revamp and modernize their blast furnaces on-time, safely and with the latest technology is paramount. In addition they must meet the detailed design, construction and safety legislation and regulations, which can be different for the various countries around the world. Siemens MT is renowned for its ability to perform Blast Furnace rebuilds, relines and modernisations within extremely tight time frames and in a safe manner. Modular Blast Furnace construction concepts have been perfected to minimise project duration and plant downtime for furnace rebuilds. Safety and certainty are the keys for success. Siemens MT are constantly introducing new technologies into the market place including cyclone gas cleaning and triple external cone gas scrubber, along with step changes in technology such as dry gas cleaning and dry slag granulation. The economic environment and the continuing requirement for improved environmental performance, drive many of these innovations. This paper describes some of the latest rebuild reference projects of Siemens MT, along with the latest technical innovations installed on these furnaces, and some of the construction methodology used for a safe and secure rebuild.

Aug 1, 2018

By J. L. Bowlby

Introduction In the following discussion, boiler-feed and mine waters will be considered from the point of view of the problems arising from the chemical nature of the mineral and gaseous impurities they contain. The theories underlying some of these problems will be reviewed for the purpose of getting a clearer concept of the problems themselves. Certain terms of a chemical nature, necessary to the discussion, will be explained on the assumption that they are not generally familiar to mining engineers. Finally, an attempt will be made to correlate theory and practice, with the abject of establishing certain limits to factors relevant to the problems, and to show that these limits are justified by practical experience. The general problems occasioned by the presence of mineral and gaseous impurities in boiler-feed and mine waters are: (1) Scale formation and corrosion in boiler systems. (2) Corrosion of mine pumps and pump fittings. These will be discussed separately. Boiler Scale Typical analyses of waters available for use in steam power-plants are given in the accompanying Table (Table I). All analytical data are expressed in grains per Imperial gallon. The bicarbonates of calcium and magnesium in the raw waters are shown as normal carbonates in the Table. Substances in the first five rows constitute the encrusting solids. All the waters listed in Table I would be classified as 'very good' in the schedule of classification for boiler waters adopted by the American Association of Railway Chemists in 1887. In spite of this classification, however, the waters contain sufficient encrusting solids to cause serious scale trouble after prolonged evaporation.

Jan 1, 1934