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By Laura E. Beverage

The Changes 2008 Brought -MSHA recently posted a PowerPoint to its website which shows statistical performance information for fiscal years 2000 to 2008. -Interesting statistics: Fatality rate in Coal dropped by nearly 30% (.0348 to .0246 per 10,000 workers)

Jan 1, 2009

By G. L. Oldright, Virgil Miller

"This paper is the tenth 4 of a series on smelting in the lead blast furnace, and the fifth 5 on modifications brought about by the introduction of richer charges.ACKNOWLEDGMENTSAll of the data on handling rich charges in lead smelting given in this recent set of five articles describing the results of a cooperative study by the United States Bureau of Mines and the University of Utah were obtained through the courtesy and with the cooperation of the staff of the Bunker Hill & Sullivan Mining & Concentrating Co. at Kellogg, Idaho. The authors acknowledge with appreciation the assistance given by Stanly A. Easton, vice.-president and general manager, F. M. Smith, smelter director, and A. F. Beasley, smelter superintendent, whose generosity, sympathy, and assistance made it possible to obtain this information for the mining industry.GENERAL DISCUSSIONWhen the charge has been dropped into the lead blast furnace, it is out of control of the operator to the extent that, whatever the material is, it must practically all be melted and run out of the blast furnace. The necessary uniformity of mixture to produce slags of regular composition and the choice of the slag—forming ingredients and products to be formed can be made only before the charge to dropped.It was found (R.I. 3096) at Kellogg, where the charge is mostly sinter, that the ratio of the slag—forming ingredients taken from each tuyere was nearly constant, in contrast to the irregular composition of slags taken similarly from a furnace whose charge consisted of ingredients differing greatly in chemical and physical nature, including size. If the charge consists almost entirely of sinter, the blast furnace should then operate more uniformly."

Aug 1, 1932

By Nilabjendu Ghosh, Satyendra Kumar Singh, Gautam Banerjee, Harshit Agrawal

High-production methods like longwall mining with hydraulic powered supports are necessary to increase underground coal production in India. Longwall mining had a mixed success record for Indian geo-mining conditions. In this paper, an analysis is presented to optimally design an array of chain pillars in multi-seam longwall mining panels in the deepest coal mine in India. The study found that a chain pillar of 80-m width and 195-m length is necessary for long-term stability without any reinforcement. It was also observed that an optimum chain pillar can be designed by providing suitable side reinforcement (side bolting) which will reduce the chain pillar dimensions to 55-m width and 160-m length. Optimum design of chain pillars will reduce the coal locked up in these chain pillars by ~ 77%. This will also reduce the gestation period of longwall mining panel development. This paper also evaluates the maximum tensile subsidence strain induced at the surface and finds that the values are within the safe working limit of 3 mm/m. Thus, this paper finds direct application in the design of future multi-seam retreating longwall mining panels in Indian geo-mining conditions.

By Nilabjendu Ghosh, Satyendra Kumar Singh, Gautam Banerjee, Harshit Agrawal

High-production methods like longwall mining with hydraulic powered supports are necessary to increase underground coal production in India. Longwall mining had a mixed success record for Indian geo-mining conditions. In this paper, an analysis is presented to optimally design an array of chain pillars in multi-seam longwall mining panels in the deepest coal mine in India. The study found that a chain pillar of 80-m width and 195-m length is necessary for long-term stability without any reinforcement. It was also observed that an optimum chain pillar can be designed by providing suitable side reinforcement (side bolting) which will reduce the chain pillar dimensions to 55-m width and 160-m length. Optimum design of chain pillars will reduce the coal locked up in these chain pillars by ~ 77%. This will also reduce the gestation period of longwall mining panel development. This paper also evaluates the maximum tensile subsidence strain induced at the surface and finds that the values are within the safe working limit of 3 mm/m. Thus, this paper finds direct application in the design of future multi-seam retreating longwall mining panels in Indian geo-mining conditions.

By J. Drelich, M. Pawlik

An improved experimental procedure to measure contact angle has been consolidated with coal surface preparation involving polishing with abrasive paper, alumina powder, and a cloth, followed by ultrasonic and mechanical cleaning. Specifically, the captive-bubble measuring technique has been compared with the sessile-drop technique and the former has been recommended for the examination of the hydrophobic properties of coal surfaces. Results of the research program, which is currently under way, on the examination of the effect of the nature, amount, size, and distribution of mineral inclusions in coal, on its wettability are briefly reviewed.

Jan 1, 1999

Breaks in coal slurry impoundments can threaten the lives and health of area residents, destroy homes and businesses and contaminate water supplies. This dangerous potential looms over coalmining regions in West Virginia and throughout Appalachia. The Coal Impoundment Project was begun in June 2003 to provide an inventory and mapping of active and abandoned impoundments in West Virginia. The project also provides the public with specific information about the impoundments in their communities. It is dedicated to alerting residents of danger and evacuation plans, reducing risk to residents and finding alternatives to impoundments. Since its first year, more than 100 impoundment sites have been added to the project’s Website.

Jan 1, 2005

By Edward Holloway

The basis for the selection of the ultimate pit for an open-pit mining operation is generally opaque. Some form of value-based analysis will generally guide the final decision; however, the value will often gradually plateau while the ultimate pit size continues to increase. There is no established framework to guide specialists in the selection of the ultimate pit, with such decisions regularly made on a somewhat arbitrary basis. The key component that is missing from the analyses typically used to select the size of the ultimate pit is risk. Once risk is quantified within the analysis framework, the decision-mak-ing range is significantly reduced and the process for select-ing the ultimate pit becomes more consistent, replicable and defensible. The technique outlined in this paper provides an approach to including risk in the process used to select the ultimate pit.

Jun 1, 2024

Rhyolitic rocks are volumetrically significant in the eastern part of the Coromandel gold province, yet deposits hosted by rhyolite (Kapowai, Broken Hills, Neavesville, Wharekirauponga and Waihi Beach) are generally low grade and subeconomic, especially compared with andesite-hosted deposits. In contrast, rhyolitic volcanic centres in Nevada host a number of economically significant epithermal gold deposits such as Round Mountain, Sleeper and Bullfrog. The Nevada deposits are associated with 27-20 Ma continental arc volcanics dominated by ignimbrites (eg Round Mountain), or younger 17-9 Ma bimodal rhyolite-basalt volcanism related to extensional basin-and-range tectonics (eg Sleeper). The Round Mountain deposit is localised on a caldera boundary fault and the mineralisation was deposited soon after eruption of the host rhyodacitic ignimbrite. In other Nevada deposits, hydrothermal systems are linked to the closing stages of flow-dome complexes and mineralisation is localised along normal faults associated with extensional basin-and-range tectonism. The style and composition of the mineralisation is similar in both the Coromandel and Nevada deposits and consists of sheeted and stockwork quartz veins, containing electrum as the main ore mineral and only minor sulphides (mainly pyrite) Likewise, the vein minerals were deposited from low salinity hydrothermal fluids in the temperature range of 200-270¦C. Both the Neavesville and Round Mountain deposits are geochemically anomalous in molybdenum. The deep oxidation of the Nevada gold deposits, dry climate and low level of competing land uses combine to make it economic to mine and process very low grade ore (0.2 - 2.0 g/t Au) by heap-leaching with cyanide solutions in most areas of Nevada. Although extensive low grade gold mineralisation is known at deposits such as Wharekirauponga and Neavesville, it is sub-economic because of shallow oxidation and land use conditions that are unfavourable for open pit mining and heap leaching.

Jan 1, 1996

By Xi Zhang

A technique for fabricating free-standing, high-aspect-ratio porous and pillar-type Ni structures has been developed using wet Si processing. A wafer of (100) Si was initially etched in HF solution to form deep pores with micron-sized diameter. The aspect ratio can exceed 200. By introducing the as-etched Si into a defined aqueous Ni2+ solution, Ni deposits grew rapidly onto the sidewalls and replaced the Si. Long-time immersion allows the Si sidewalls to be completely converted and thus form a metallic Ni structure with high-aspect-ratio pores. It is known that close-packed submicron Si pillars can be formed by oxidizing and subsequent etching of the macropore sidewalls. Treated in the same Ni solution, high-aspect-ratio Ni pillars were correspondingly emerged by replicating the original pillar-type Si structure.

Jan 1, 2006

By Richard C. Barth

Fourteen field plots were established at active coal mines in the Northern Great Plains. A wedge was cut into spoil and backfilled with soil; soil depth ranged from 0 to 152 cm over a linear distance of 15 m. Perennial grasses were planted in each plot, and production was measured from 1978 to 1981. Based on spoil traits and biomass response patterns, plots were grouped into four types. Spoil for Type I plots was near neutral, slightly saline, nonsodic, and clay loam in texture. Perennial grasses reached maximum production with approximately 50 cm of soil depth. Spoil for Type II plots was characterized as sodic and fine textured; soil-depth requirements averaged 83 cm for maximum production. Spoil for Type III plots was characterized as strongly acid, and production increased throughout the soil depth range tested. Spoil for Type IV plots was similar to soil in chemical and physical traits; there was no production response to soil depth. Soil depth requirements were also dependent upon precipitation and species. In general, soil-depth requirements decreased in dry years and with use of introduced species. An appendix contains data evaluations on an individual plot basis.

Jan 1, 1982

By Fan Shaogang

In this paper, the airbags' structure and technical characteristics and its applications in China are described. Based on the practice of the airbags in mining thin seams, the effects on ground control are discussed. This paper also analyzes the interaction mechanism between the airbag and surrounding rocks.

Jan 1, 1997

(Published by courtesy of the Great Boulder Pty. Gold Mines, Limited)1. INTRODUCTIONThe faults described in the following paper are of a somewhat unusual character, and have presented a serious problem both in the development and mining of many ore-bodies on the Eastern side of the Boulder Belt. They are mentioned only briefly in the literature of the field, but were observed by, both Stillwell (1)t and Gustafson (2), and have been studied by other geologists and operators in various parts of the "Belt." Their effect on the lodes of Hamilton Section, Great Boulder Mine, was described by King (3) in 1937, and, during recent years, they have been encountered in most of the Great Boulder workings extending east of the Boulder Dyke.Although this paper is based mainly on a study of faulting and development problems on the Great Boulder mine, the general conclusions reached may be applicable to the solution of similar faulting problems in other mines throughout the field.In order to arrive at a clear understanding of the somewhat complicated relationships which the east-dipping faults bear to the lode systems it will be necessary to give a brief outline of the salient geological and structural features of the "Belt" before proceeding to describe the faults themselves.2. GENERAL GEOLOGYThe most recent descriptions of the geology of Kalgoorlie are those by Stillwell (1) and Gustafson (2) and the reader is referred to these as representing the basis of current knowledge of the geology of the field.The Boulder Belt is comprised of a central core of altered quartz dolerite which is flanked on either side by fine grained greenstones and lavas, usually referred to as the calc schists. Down the centre of the quartz dolerite mass there is an infolded bed of slate (2, p. 105) which has been intruded in lit par lit fashion by albite porphyry; the composite body of slate and porphyry so formed is known as the "Boulder Dyke." Numerous smaller porphyry dykes intrude both the quartz dolerite and the calc schist; these vary in composition and range from chloritised hornblende porphyrites to albite porphyries.The whole of the rock assemblage has been subjected tG a considerable amount of folding, faulting, shearing and fracturing, the greater part of which took place before the formation of the lodes.

Jan 1, 1941

By P. T. Allsman

INTRODUCTION The honor of being the recipient of the Mining Society's Daniel C. Jackling Award for 1966 imposes on me the responsibility to search for the subject that I would be best qualified to discuss. It seems that my experience in the mineral industry — nearly 15 years in private and 30 years in public employment — should uniquely qualify me to comment upon the relationships between the mining industry, mineral engineering as a profession, and government, and the changing economic, technologic, political and social changes that dictate their relationships. Such conditions, the increasing knowledge of the world mineral resource base, the greater demands of an expanding population with a rising standard of living, shall be evaluated with respect to our profession — mineral engineering. In all of these forty or so years, I have been in close touch with many phases of the mineral and energy resource industries, especially those of the United States. Particularly during the past 10 years, I have had a ringside seat at the "goings on" in Washington. During all of this period I have observed and analyzed many of the problems of the industry and its relations with the government. During the past few years, I have had increased opportunity for doing research and have found a need to learn something about the mathematical techniques that are undergoing such a revival since electronic computers were developed. One of these techniques is multivariate analysis, which is a system for correlating a large number of complex variables. By applying this technique to the seemingly chaotic present-day situation, there emerges a course of steady improvement in the minerals resource industries that wars, depressions, and political strife have failed to obstruct for long. In short, I advocate a need for new concepts in mineral engineering to cope with the changes, pos- sibly adding many more specialized areas on one end of the spectrum, and broad engineer-generalist approaches at the other. The meeting place shall be where the intricate mineral resource problems at the frontier of knowledge merge into the socio-techno-logical problems of the world. HISTORICAL INVOLVEMENT OF GOVERNMENT IN MINERAL RESOURCE PROBLEMS Involvement of government in mineral resource problems undoubtedly is as old as government itself. But passage of the Mining Act of 1866, superseded by the Act of 1872, was the first major entry of our Federal Government into the problems of mining. Passage of the law was necessary to resolve many conflicting claims and disputes in mining. The General Mining Law of 1872 and the Mineral Leasing Laws of 1920 apply to millions of acres of public lands and to certain privately owned land on which the mineral rights have been reserved to the Federal Government. The extensive involvement of government in the mineral industry business today often comes as a shock to the mineral engineer who has begun to climb the ladder to the top in his company. He is often poorly prepared to cope with the situation and becomes frustrated and even hostile. Better knowledge of the role of government perhaps would ease his situation. In our political system, private industry is responsible for producing minerals. To make certain that the production is adequate for a peace-time economy, and to guarantee the Nation's security in an emergency, the Federal Government finds it expedient to develop policy and engage in regulatory, educational, and research activities. A few examples will illustrate the varied role of government in relation to mineral problems. In varying degrees many agencies of the Executive Branch of Government have responsibilities that influence the functioning of the mineral and energy industries. In addition, of course, Congress, the Judiciary, and State and local governments exercise great influence. The Department of the Interior is primarily responsible for activities to promote the development and conservation of mineral and fuel resources, and the

Jan 1, 1967

By Z. Sun, H. A. Davies

"Current understanding of the mechanisms by which glassy and crystalline thin ribbons are formed in high speed continuous casting processes is considered. A computer model of the combined heat and momentum transfer during melt spinning has been developed. The influence of roll velocity and of heat transfer coefficient (between the melt and the roll) on the temperature and velocity distributions within the melt puddle is analysed and the thickness of the extracted ribbon computed. The relative importance of heat and momentum transfer under different conditions is assessed and differences between the casting of crystalline and amorphous strip highlighted.IntroductionHigh speed continuous casting of thin metallic ribbon and strip is currently of considerable interest both to metal processers and to those studying process mechanisms. The practical interest arises both from the potential economic benefits to be gained from a shorter and more energy-efficient production route and from the ability to obtain extended and uniform thin strip having a metastable microcrystalline or amorphous structure with enhanced or unique properties. The latter arise from the rapid solidification associated with the cooling of very thin sections of melt brought into intimate thermal contact with one or two rapidly moving heat sinks.The principal processes for casting thin strip include free jet, chill-block melt-spinning (GBMS) (1), melt drag (MD) (2), planar flow casting (PFG) (3) and twin-roll casting (TRG) (4). For the first three of these, all essentially variants of melt-spinning, melt flows through a nozzle onto the circumferential surface of a rapidly rotating roll, whereas for TRG the melt passes into the nip between two contra-rotating rolls. We shall be concerned in this paper with the single-roll melt spinning processes only. For these, a puddle is established where the melt contacts the roll surface and the length of this puddle l is a function of the process conditions, notably the circumferential velocity of the roll Us and the volumetric flow rate of the melt Q. The contact time between any point on the roll surface and this puddle, or residence time eR(= l /Us) determines the thickness of ribbon t extracted from the puddle. This thickness, in turn, partly governs the cooling rate T and the amount of undercooling in the melt and thus the microstructure of the solidified ribbon."

Jan 1, 1986

By Maarten van de Vijfeijken, Marco Rufli

"By using the latest generation of medium voltage frequency converters, new possibilities have arisen to improve the grinding process. Beside all the direct and indirect advantages, several dedicated functions have now been implemented for ring geared grinding mills in the minerals industry. The advanced operational functions ensure a smooth, safe and reliable operation with minimum stress for the mechanical equipment and therefore highest availability of the mill. Several papers have already been presented concerning the benefits of using this state of the art technology for mill drives (Ravani von Ow and Bomvisinho, 2010; Ravani von Ow and Gerhard, 2010). However this paper will not only show and explain the operational benefit of these functions, but will focus on the experiences gained with this kind of sophisticated ring geared mill drive system. Several measurements of different operating conditions (starting, frozen charge remover, controlled roll back, backlash, etc.) made on an installed and commissioned 2 x 5 MW dual pinion ring geared mill drive system will be shown and discussed. Also the accuracy of the load sharing between the two 5 MW motors during starting, normal operation and stopping will be demonstrated using real measurements from an operating system. Finally the inherent features of these drive systems are briefly discussed.INTRODUCTIONLooking at the demands of grinding mills, we can split them into operational, maintenance and protective demands. For smooth and safe operation, it is important that critical situations are avoided as much as possible. Maintenance functionality must be quick and easy to execute, while protection of the system is important during all operating conditions. ABB has considered all these demands during development of their dedicated mill functions. By adding an additional controller (mill controller), not only a lot of application related functionality and protection is included, but also the interface between the mill drive system and the customer’s distributed control system (DCS) is simplified."

Jan 1, 2011

By D. D. Blue

To insure domestic production of aluminium for, essential civilian and defense uses, the Government, under authority of the Defense Production Act of 1950, programed and promoted an aluminum-expansion program that will more than double the primary production capacity that existed in 1949. In view of this vastly increased production, the raw materials, with respect to both quantity and sources, are reviewed. The raw-material consumption pattern, the requirements during an expansion period when excess quantities of materials for starting up new facilities are consumed, and the probable requirements for production of 1.7 million tons per year of primary aluminum are discussed. The raw materials that presented the most difficult supply problems were bauxite, electrical power, and fluoride salts, and the supply pattern for these materials probably will undergo changes. A major part of the electrical energy for the increased capacity was to come from thermal generation, Jamaica-was to become a major source of bauxite, and synthetic fluoride salts were replacing natural cryolite in increasing quantities. Other raw-material requirements discussed are: Soda ash; lime, and limestone; starch; filter cloth; fuel; alumina; the carbonaceous materials, green and calcined petroleum coke, high-and low-temperature pitch and coke or anthracite; cryolite; aluminum fluoride; the materials going into production of synthetic fluorides, acid-grade fluorspar, and sulfuric acid; and labor. INTRODUCTION The raw materials for the aluminum industry that have received the most publicity are bauxite, the ore that supplies elemental aluminum, and electrical energy, the means by which aluminum oxide is reduced to metal. A number of other important materials are, however, required in large quantities in the production of primary aluminum metal.

Jan 1, 1954

By Warren L. J, Horsley R. R, Meagher L

Mineral concentrators often use process water that is very saline and/or hard. In this paper the effect of increasing concentrations of sodium chloride and calcium chloride on the rheological properties of 70 wt% quartz suspensions (d5o - 10.6 ¦m) is reported. The apparent viscosity at 100 s t in 5 mol dm -3 sodium chloride solutions (approx. 300,000 ppm) was nearly 500 times the viscosity of water without salt or particles present. Part of the increase in viscosity is caused by aggregation (coagulation) of the suspension.

Jan 1, 1989

By Diankun Lu, Ganfeng Tu, Edouard Asselin, Feng Xie

A novel separation process for detoxifying cadmium-containing residues arising from zinc hydrometallurgical processes has been developed. An initial investigation indicated that a high concentration of zinc in the sulfate solution can be effectively separated from cadmium by solvent extraction with P204 (di(2-ethylhexly)phosphoric acid, D2EHPA). The mixture of sulfuric acid and ammonium citrate ((NH4)3C6H5O7) is thus used to extract metals from the residue at room temperature. Copper in the leachate is recovered by solvent extraction (SX) with LIX 973. Cobalt in the raffinate from the copper SX process is recovered by precipitation with a-nitroso-ß-naphthol. The results show that more than 50% of the copper and virtually all the zinc, cadmium and cobalt in the residue can be leached under the experimental conditions used here. Virtually all dissolved copper and cobalt can be recovered in the subsequent solvent extraction and precipitation processes. The presence of (NH4)3C6H5O7 could significantly facilitate the extraction of zinc by D2EHPA in the subsequent separation of zinc and cadmium. More than 97% of the dissolved zinc can be recovered through a two-stage counter current solvent extraction process. After separating copper, cobalt and zinc, cadmium can easily be recovered from the solution either by cementation with zinc powder or by electrowinning, while the purified solution can be recycled back to the leaching process.

Jan 1, 2014

By B. O. Odera

The Pt-based alloys have a high potential for replacing some Ni-based superalloys (NBSAs) used in the highest temperature and most aggressive environments, and vanadium would be a beneficial alloying element. Six alloys of average compositions Pt-26.6Al-9.1V, Pt-23.1Al-17.8V,Pt-9.6Al-21.1V, Pt-17.4Al-6.4V, Pt-22.3Al-7.9V, and Pt-6.0Al-10.1V (all in at.%) were manufactured by arc-melting and examined in the as-cast condition using scanning electron microscopy and X-ray diffraction (XRD). Five samples were heat treated at 1 000°C for 1 500 hours and water quenched, then examined. The phases were identified using energy-dispersive X-ray spectroscopy and the identities were confirmed by XRD. In most of the samples, the phases existing in the as-cast condition were different from those at 1 000°C after ~1500 hours heat treatment. A solidification projection, an isothermal section and a liquidus surface projection were determined for the Pt-rich corner.

Jan 1, 2012

The district specially referred to in this paper comprises the very gently sloping country extending from the western shores of Port Phillip from the mouth of the Yarra to Footscray along the Bacchus Marsh railway to near that town thence in a southerly direction to the Little River, and along that river to the coast, 1 as may be seen on the accompanying map. Almost the whole of this area is covered by volcanic rocks, consisting of pumerous sheets of basalt, which have been poured out of various volcanic hills in the districts, such as Mts. Atkinson and Cotteril, near Melton; Mt. Maryand Bald Hill, 12 and 16 miles respectively N.W. of Werribee; and vents in different parts of the parishes of Tarneit, Mouyong, Mooradoranook, Pyweitjorrk, and Derrimut. These volcanoes were in an active state of eruption during a late period of the earth's historyprobably the late Pliocenll, or still younger Pleistocene.Occupying a narrow strip of country, for most of the distance along the coast from Williamstown to past the mouth of the Little River, there occur deposits of still younger age, belonging to the Recent period. These lie on the basalt, and extend for distances varying from a few chains to more than a mile back from the beach. They comprise superficial deposits of blown sand, and raised beaches, composed of marine sands...

Jan 1, 1902