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[†Aaronson, Alfred E., Oil Producer, Pres., Tuloma Oil Cc Tulsa, Okla. '18 ¦Abad, Leopoldo F., College of Min., Univ. of California Berkeley, Cal. '23 ¦Abadilla, Quirico A., Geol. Dept., Cia. Mexicans de Petroleo "EI Aguila," S. A., Edifico "El Aguila," Esq., Calles Aurora y Comercio, Tampico, Tamps., Mexico. '20 ¦Abbey, Robert Graham, Student, Case School of Applied Science Cleveland, 0. '21 Abbott, Clarence E., Gen'l Supt., Iron Mines Div., Tenn. Coal, Iron & R. R. Co., 1405 Minnesota Ave., Bessemer, Ala. '04] [ ]

Jan 1, 1925

By AIME AIME

DESTRUCTION of the plants, machines, utilities, tools, materials, and other essentials for peacetime living penalizes not only the owners of the materials destroyed, but the world as a whole. Specifically, the fundamental fallacy of any proposal for the in- discriminate destruction of the German industrial system is that it fails to differentiate between the wartime and the peacetime economy of the Reich. We are for one simple, clear objective-an effective industrial means to keep Germany from starting another war. This objective should not be con- fused, especially before the war is even won, with the appropriate punishment of Germany or with the international arrangements for the long future to be made around the peace table by the representatives of the Allied Nations after victory is achieved. This paper, therefore, does not deal with broad, complex postwar questions of diplomacy and international policy. "Unconditional surrender" implies disarmament of the German armies, the surrender of all arms, munitions, air- planes, and other ordnance material in stock piles or in process. It also should include the elimination of all German war production facilities, such as ordnance plants, munitions plants, and submarine works, and the control of raw materials required by war industries.

Jan 1, 1944

By J. F. T. Agapito, L. J. Gilbride

High horizontal stresses were recognized to impact roof stability more than 60 years ago. Since then, numerous measurements associated high horizontal stresses with difficult ground conditions. This paper presents case histories illustrating the practical usage of roof stress determinations for helping assess stability, not only in the case of high horizontal stresses but also of low stresses. Examples are given of high stresses associated with faults, mine design changes, quantification of stress shadow effect, and anistrophy. The paper concludes with a comparative evaluation on the effect of various stress fields on ground support requirements.

Jan 1, 2002

The development of present methods of pillar extraction has evolved from the very earliest of hand mining operations which were limited in scope by venti- lation and transport considerations. Conservation and safety considerations also have led to the current shortwall operations with conventional equipment and powered supports. The shortwall methods have had significant effects on safety, costs, con- servation, flexibility, and other aspects of pillar extraction. The present stage falls short of the ideal but is some guide to prediction in what direction may lie the ideal methods for the future.

Jan 1, 1974

By L. N. Hill

The classifiers on the primary grinding circuit at Cyprus Sierrita have been upgraded from 0.66 m (26 in) diameter hydrocyclones to 0.84 m (33 in) diameter hydrocyclones. This has resulted in a 4.3 % (11 t/h) (12 standard tons/hour) increase in mill throughput while producing a flotation feed which contains 4.8% less +300 micron (48 mesh Tyler screen size) material. This reduction in flotation feed particle size has increased copper (CU) recovery by 0.8 %. Various grinding circuit relationships were evaluated. These relationships include circulating load versus throughput, horizontal versus vertical cyclone configuration, and the effect of cyclone components on performance. We conclude that the improvements achieved are due to a shift in the overflow size distribution created by a cyclone diameter more suited to our operation, and by eliminating the cyclone capacity constraint in the grinding circuit.

Jan 1, 1994

By J. L. Thornton

Introduction The importance of coal in our economy is well established, but it may not .be so generally realized how important a part it plays in our daily life. Select a product - any product - and, if it is made in America, bituminous coal has touched it first. Everywhere we will find coal, derivatives of coal, or functions made possible by coal. Apart from the well known major uses of coal for domestic purposes, coking, utilities, railways, and manufacture of steel and cement, there are over 200,000 products derived from coal, from lipstick colours to nylon products and perfumes. An item of interest is the recent action of the Canadian Government in voting $90,000 for development of coal deposits in Yukon Territory to make coal available to the settlers in that area. The value of this move, in case of some emergency, is very evident. Coal in its several stages of formation as peat, lignite, sub-bituminous, bituminous, semi-bituminous, semi-anthracite, and anthracite, has been used for centuries. Coal, as such, was not very well known to the ancients. First reference to "magic stone', or coal, was in 371 BC by Theophrastus, a pupil of Aristotle. This substance was said to burn like wood coal or charcoal and was used by the smiths. The first record we have in modern times was in 852 AD, when sea coal was gathered by the cowled monks of Durham, in Britain, and even at that time a major problem was transportation. Our first record of coal in this continent was near Richmond, Virginia, in 1700. Commercial mining was not under way, however, until 1750. The anthracite fields (presumably in Pennsylvania) were opened in 1793. Even so, there was no extensive mining until about the year 1820. The famous Pocahontas coalfields were opened in 1883. The earliest record of coal mining in Canada is about 1746.

Jan 1, 1950

By J. C. Agarwal

Slags produced by modern smelting furnaces contain copper values which are unacceptably high for discard. The electric arc furnace is employed commercially to clean copper from flash furnace slags but the addition of highly oxidized converter slags to an electric furnace has created operational problems. Highly oxidized Noranda Reactor slags have not been processed successfully in a pyrometallurgical process. These slags, which contain large concentrations of copper (5 to 10 per cent), are treated in slag concentrators (controlled cooling, crushing and milling, and flotation) which produce a copper concentrate that must be resmelted. Though commercially operable, it will be shown that the slag concentrator has important process and cost disadvantages as compared to a pyrometallurgical process. In this paper an economic comparison is made between a pyrometallurgical process and the slag concentrator. For the analysis, five hypothetical smelting plants are considered. Each plant treats 1200 tons of copper concentrate per day and produces 109,000 tons of copper annually. The plant configurations used in this study are:

Jan 1, 1976

By AIME AIME

THREE of the addresses presented at this interesting and important session are printed in full else- where in this issue. The fourth, Mr. Hewett's paper, on "Cycles In Metal Production" has been issued as Technical Publication 183, and an abstract of it was published on page 162 of last month's issue. The general discussion that followed these four important papers is given in full below. S. A. TAYLOR: I would like to ask Mr. Veasey whether the control of oil in pools includes royalties, and, if so, in case of a new pool how are you going to control, or rather how are you going to describe the limits of that pool?

Jan 1, 1929

By White A. H, Gillies A. D S

In recent years the Australian gold industry has gone through a major expansion phase. The need for finance has led to adoption of different approaches such as the well known gold loan, forward selling, equity participation by suppliers and equipment leasing. During early periods of the expansion, significant new equity was raised chiefly for high risk exploration ventures. The major form of new equity finance was ordinary shares, often in 'No Liability' companies. The increasing capital requirement of the huge new development projects of the 1980s also spurred the use of debt finance. This trend was accelerated as high inflation and the taxation advantages of debt finance made borrowing attractive. This paper reviews major financing techniques used by the Australian gold industry with particular emphasis on the innovative financing techniques initiated recently. An analysis has been undertaken of the effects on the industry of issues such gold loans, forward selling, equity participation by suppliers, fly-in fly-out operations, contractor mining and equipment leasing. In order to achieve a better understanding of the innovative financing techniques, a survey of already published financial data from well known Australian gold mines was carried out. Data was collected from various published financial reports of gold mining companies. In addition, a questionnaire survey was sent to gold mining companies to assist the collection of further information. The results of this study show that there are a significant number of gold mines variously using gold loans, forward sales, contractor mining and fly-in and fly-out arrangements to finance their projects. Only four operations have vendor suppliers investing capital funds in their projects. Based on the findings of this study, conclusions and recommendations are drawn that these approaches are likely to be with Australian gold industry for some time in the future and will continue to be intensively applied to finance gold projects.

Jan 1, 1994

By D. O’Connor, A. Pytlik, D. J. Corbett

The resistance of yielding rockbolts to multiple impact loads was tested by means of a drop hammer. The methodology was based on the ASTM D7401-08 standard as well as the requirements specified for rockbolts by Luossavaara-Kiirunavaara Aktiebolag (LKAB – a Swedish mining company) and the Safety In Mines Research Advisory Committee of South Africa (project number GAP 423). During the tests, the loading force and bolt elongation were measured with a sampling frequency of fs = 19.2 kHz. In order to analyse the phenomena involved, the tests were recorded using two independent high-speed video cameras (600 and 1000 frames per second) and one thermal camera (128 frames per second). The tests demonstrated that all the samples transferred double the gravitational potential energy of Ep = 50.85 kJ from the impact load of mass m = 2825 kg and impact velocity of v = 6.0 m/s without failure. Damage to the bolt-resin contact in the upper anchoring zone of the bolt in the steel tube occurred after subsequent impacts. As a result, the macro-deformed bolt exhibits additional yield, and its operation following the shearing of the resin bond is similar to that of a ‘cone bolt’. Only one test resulted in damage to the threaded bolt rod-nut coupling, during the fourth impact; however, no damage to the bolt-resin contact zone was observed.

Nov 6, 2023

By B E. Hall, J Poniewierski, A J. Hills

Following a review of life-of-asset work at MMG’s Rosebery mine in which a proposal to increase production from 0.8 Mt/a to 1.2 Mt/a was mooted, questions were raised as to the seemingly arbitrary reasoning for the production increase. They included: Did the proposal actually add value? Was the production rate from the mine sustainable? Was it the best identifiable value-adding configuration?A multiple scenario analysis study commenced to model how various cut-off grade values against mill throughput, along with associated capital expenditure, would impact on the potential value of the operation. This was carried out utilising the ‘hill of value’ approach promoted by AMC Consultants.The traditional approach to these studies uses a constant cut-off value (NSR – net smelter return) for the whole mine analysis. This was thought to potentially introduce a large amount of variability to the model as different ore types were thought to have different processing costs and different underground lenses were thought to have different mining costs. With the aim of developing a consistent value measure that would be comparable between the lenses, an alternative measure was suggested for all ore block values in this model, irrespective of lens location.The new measure used was a mine variable value (MVV). This allowed for the variable factors of final metal concentrate production to be removed from the ore value. From a mining point this was the haulage distance from ore source to run-of-mine (ROM). For the mill it was the amount of reagents required, varying based on grade together with the amount of power required for crushing, grinding and tailings handling.From the initial run of the model, preliminary results lead to a conclusion of increased value being gained by either increasing cut-off grade or increased mill throughput rate. The validity of the result was tested using alternative price scenarios, which although changed the absolute value achieved did not significantly change the identified value-adding strategies. The realisation of these value increases identified are however contingent on higher sustainable development rates being able to be achieved mine-wide, higher backfilling rates being able to be achieved and overcoming recognised ventilation constraints. Further detailed studies are being put in place to identify the practicality of overcoming these recognised constraints and achieving the higher-value strategies identified.The ongoing objective of the hill of value model built is to keep the model alive as a life-of-asset planning tool and to continue refining the foundation data, such that various mining strategies can be analysed with increased confidence.CITATION:Hills, A J, Hall, B E and Poniewierski, J, 2014. Mining scenario analysis and mine variable value, in Proceedings 12th AusIMM Underground Operators’ Conference 2014 , pp 111–118 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Mar 24, 2014

By T. K. Bose

According to the Intergovernmental Panel on Climate Change (IPCC), the average global temperature has risen over the last century. If this trend continues over the next century, the IPCC projects a significant increase in temperature and a rise in sea level. The changes in climate could adversely impact human health, agriculture, water resources and ecosystems. Most national and international agencies have concluded that our use of carbon-rich fuel is responsible for global warming through the greenhouse effect. In the future, the situation may get worse if the increased need for energy in countries like China, India and Brazil is fulfilled by burning fossil fuel. Advanced natural gas-fuelled vehicles have the potential to reduce carbon monoxide and reactive hydrocarbon emissions substantially compared to gasoline vehicles. Further environmental benefits can be realized by using a blend of natural gas and hydrogen. Such an approach will help create an infrastructure for an eventual transition to hydrogen.

Jan 1, 2005

By Yunxing Cao, Xinsheng Zhang, Bingbing Meng, Shuaifang Guo, Li Wang, Junsheng Zhang

During the initial process of mining a longwall working face, it is often found that the roof will not collapse readily, which increases the risk of later roof collapse disasters. Explosive and hydraulic fracturing are common roof weakening techniques; however, they have certain limitations. In the present study, CO2 fracturing was used for roof weakening during the initial mining phase in the Changcun coal mine, China, which is a novel strategy. First, by analyzing the lithological characteristics of the working face and applying combined beam theory, the breaking spans of the top coal, immediate roof, and main roof were determined before weakening. An F-35 CO2 fracturing device with a rated pressure of 270 MPa was used, which provides fracturing energy equivalent to 0.968 kg of TNT. The fracture radius of the main roof was studied by ANSYS/ LS-DYNA combined with the hanging roof-breaking theory to determine the optimal layout of CO2 fracturing drills. The results show that the breaking spans of the top coal, immediate roof, and main roof were reduced by 3.99 m, 7.66 m, and 22.03 m, respectively. The main roof collapsed as the working face advanced, eliminating the chance of later roof collapse disasters. Compared with hydraulic fracturing and explosives, CO2 fracturing is safer and more practical, giving it significant application potential.

Nov 23, 2023

By Albert L. Toenges

This circular deals primarily with the various methods of longwall mining used in some mines in certain districts of the Middle Western States. In some instances underground methods were considered comprehensively, and in others only the actual methods of mining and face advance were noted. Results obtained by the mines in output per man were compared only on the basis of an operating day, since idle time and number of men employed would not, be comparable due to the great difference between mines in different districts. Man-hours per ton per operating day are noted in a general way. Material and power costs are not included. ACKNOWLEDGMENT The information used in preparing this paper was obtained through the courtesy and cooperation of the presidents and other officials of the comparnies operating the mines described. The approval of the executive of each property was obtained for publishing this manuscript, and the accuracy was checked.

Jan 1, 1936

By Jr. Koch

As a part of a larger study of the distribution of metals within ore deposits, the geometry of distribution of gold, silver, lead, copper, and zinc in five veins of the Fresnillo mine, Zacatecas, Mexico, was established. The purpose was to obtain basic data necessary for evaluation of geological theories about processes of vein formation and useful for practical mining applications in ore estimation and prediction of ore beyond present workings. The Bureau of Mines investigation comprised statistical analysis of 64,000 assay values from some 16,000 mine samples. The samples were taken at 2-meter intervals in drifts exposing the veins through a vertical range of some 750 meters. Within individual veins, the metals are distributed in dome¬like patterns with highest metal contents tending Lo occur in oreshoots at the centers of the developed parts of the veins. However, in the block of ground containing all five veins, base metals define mathematical domes with highest contents near the center; precious metals define mathematical basins or troughs with low contents near the center. The ratio of silver assay values to lead assay values corresponds to two geographically distinct types of mineralization: one in which silver is closely related to lead, and another in which silver is independent of lead. Other metal ratios also vary regularly from one place to another. The statistical methods employed in this study would be useful for other geologists or engineers who need to analyze large amounts of assay or similar numerical data.

Jan 1, 1967

By Arthur L. Crawford, R. E. Head, Glen Burgener, F. E. Thackwell

"INTRODUCTION This report embodies the results of a detailed statistical microscopic examination of the ore and the mill products of the Silver King Coalition Mines Co., Park City, Utah.The study was conducted under the joint auspices of the United States Bureau of mines is cooperation with the University of Utah at Salt Lake City, Utah. The work was done in the cooperative Microscopic Service Laboratory, which was equipped by contributions from the following companies: Utah Copper Co., International Smelting & Refining Co., American Smelting & Refining Co., United States Smelting, Refining & Mining Co., Tintic Standard Mining Co., Silver King Coalition Mines Co., and Park Utah Consolidated Mines Co. The salaries and the other costs involved in operation of the laboratory were met by contributions from certain supporting companies. In addition to the regular personnel of the laboratory the Bureau of Mines contributed the part-time services of a microscopist-consultant to direct and assist with the technical work.ACKNOWLEDGEMENTSThe authors acknowledge the courtesies extended by the Silver King Coalition Mines Co., through its general manager, M. J. Dailey, in furnishing the various ores and products on which the study was made, together with general information concerning the problems encountered or recognized in connection with the milling of the Silver King ore."

Jun 1, 1934

By Victor Himel

This report documents a systematic approach towards implementing an improved ensemble for the mine rescue team system that will protect against the hazards of mine rescue and recovery and will also afford improved performance through increased comfort and maneuverability, lighter burdens, and improved human engineering designs. In the first part (Task 1) the mine rescue team's protective needs were defined along with the test methods required to evaluate whether a particular piece of gear met these needs. Task 2 assessed existing gear against performance criteria and standards developed in Task 1. Task 3 consisted of the conceptual design and construction phases of the MRPE program. Special consideration was given to advanced concepts, materials, and equipment.

Jan 1, 1982

By Shusen Cheng, Dongdong Zhou

The high temperature distribution in ironmaking and steelmaking industry is very important to control the smelting process. Although equipment is available to measure the temperature in the smelting process, in general it could just measure one certain point or only at discrete times. The real time temperature distribution in ironmaking and steelmaking is important because it could reflect reaction information and help to control the operation parameters. In this paper, a new method to detect the temperature distribution in ironmaking and steelmaking through the application of digital imaging system based on the color CCD was studied. In addition, the two-color method and partial least square method were used in the calculation model to improve the accuracy. The results agreed well with the measured temperature.

Mar 1, 2017

By Mark J. Zdunczyk

"Frac sand is industrial silica sand much like glass, foundry, filtration and blast sand. The sand must meet certain specifications set forth by the industry that consumes the product. The production and consumption of frac sand has experienced record growth in the last 10 years because of new oil and gas drilling, new horizontal well drilling, multi-stage fracturing and the stimulation of older wells that have little or no production. Frac sand is needed to “prop open” the fractures in the rock reservoirs to allow oil and gas to flow out more freely.According to the U.S. Geological Survey (USGS), the estimated production of frac sand in 2015 was 71 percent of the total production of industrial silica sand or 67.4 Mt (74.3 million st). This is a decrease of about 12 percent from 2014. However, the silica sand industry and other industry sources estimate only 50 Mt (55 million st) of frac sand were produced in 2015. In recent years both the USGS and industry studies have been very close in estimating the production of frac sand but with the recent downturn in frac sand production, perhaps, reporting to the USGS was not as accurate. These discrepancies may be that the USGS statistics are based on voluntary reporting by the industry and some companies report their approximate production, others may not. It is always difficult to obtain accurate production figures of any industrial mineral or construction aggregate operation as most companies tend to keep those figures somewhat confidential. It is certainly accurate to report that the production of frac sand had decreased since the last quarter of 2014 and through 2015. The oversupply of oil and natural gas has led to this decline in frac sand usage. Oversupply has idled drilling rigs and well completion activities. World Oil Magazine reports that 2015 was the worst year for rigs in a quarter century. The only wells being completed are those that have contract agreements to do so, others have been capped. Very few new wells are being drilled. Since about 98 percent of well completion is sand and water, the sand supply has caught up with the demand. There are some bright spots in the “oil patch” as the Permian Basin in Texas and the Woodford Shale in Oklahoma have kept pace somewhat with drilling and completion. It has been reported that the frac sand producers in the Brady-Voca, TX area are producing to nearly capacity. The northern frac sand producers like those in Wisconsin, Illinois and Minnesota are feeling the downturn because of the cost of shipping sand to these moderately active basins and plays. The “rule of thumb” is that freight is 2/3 and sand is 1/3 the cost."

Jul 1, 2016

By Michael Tenenbaum

The importance of semikilled steel as a high tonnage grade has long been recognized. The increasing severity of the applications for which semikilled steel is used makes it desirable to obtain further information regarding the features of open hearth practice and ingot structure that can affect steel performance in subsequent rolling and fabricating operations. Accordingly, an investigation is being carried out studying the structure of various types of semikilled steel ingots. This paper reviews some of the observations made and information gathered in this investigation. By definition, semikilled steel may be considered to include all nonrimming steels in which the natural shrinkage occurring during ingot solidification is offset to an appreciable degree by gas formation. Accordingly, this type of steel includes the entire range intermediate between rimmed and fully killed steel. The resultant ingot structures range from those of steels that have been capped to suppress a weak rimming action to those steels that have been killed in the furnace or ladle to the extent that no mold deoxidizer is required. A survey reported to the 1946 -AIME Open Hearth Conference' reviewed the practices being used at 28 major plants for the deoxidation of semikilled steel. It was found that most plants divide the deoxidizing additions between the ladle and the mold—many of the plants adding only minor amounts of deoxidizer to the bath or none at all. Silicon, aluminum and titanium were the only elements used for ladle and mold deoxidation. Mold deoxidizers were added as capping additions or as uniformly fed additions. Several practices were reported in which the steel was deoxidized in the ladle to the extent that little or no mold deoxidation was needed. No reference was made to grades capped by using special mold designs or special closures over the top of molds. .Accordingly, specific examples of this type of practice will not be considered in this paper. It appeared from this survey of deoxidation practice that semikilled steel can be divided into three types, namely, capped semikilled, in which aluminum is added near the end of pour or after shut-off, intermediate semikilled steels, in which aluminum is fed uniformly throughout the pour, and semikilled steels requiring no mold deoxidation. In an attempt to cover the ingot structures obtained by the range of practices reported in the preceding survey, three series of experimental heats were made using increasing amounts of aluminum, silicon and titanium for ladle deoxidizers. The ladle deoxidizers were added as stick aluminum, 50 pct ferrosilicon and 20 pct ferrotitanium (4 pct carbon), respectively. Two methods of studying ingot structures were used. Ingots were removed from production, burned longitudinally and machined to allow observation of the central pipe and coarse blowholes. During the machining operation much of the finely porous subsurface structure was obliterated. Accordingly, observations were also made

Jan 1, 1949