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By A. B. Campbell

The mines in the eastern part of the now active region of the Tri-State zinc district of Missouri, Kansas, and Oklahoma have unusually acid water, which during periods of moderate or no rainfall is used in the mills to replace losses from evaporation, seepage-, and tailings disposal. Its use has caused difficulties by corrosion of equipment and by interference with flotation. The growing importance of flotation, which requires good water, and the increasing troubles caused by the corrosion of the milling equipment have prompted the Mississippi Valley Experiment Station of the United States Bureau of Mines, in cooperation With the Missouri School of Mines and Metallurgy, Rolla, Mo., to investigate the action of the waters on flotation and to undertake to develop means of obviating their harmful effects. The work was under the immediate direction of W. T. Schrenk, consulting chemist, United States Bureau of Mines, and professor of chemistry Missouri School of Mines and Metallurgy, and. Will H. Coghill., supervising engineer of the ore dressing section of the United States Bureau of Mines.

Jan 1, 1932

The Bureau of Mines in the Department of the Interior is increasingly concerned with the safety and health of personnel engaged in coal-mining operations, particularly below ground. The Bureau is also concerned with improving the utilization of domestic mineral resources, and reducing the environmental impact of mineral operations. One obvious way to improve safety and minimize health hazards would be to eliminate coal mining entirely by bringing the energy value of the coal to the surface in some other way, such as by partially burning it underground to form combustible gases and bringing these gases to the surface, where their energy content can be put to use. This technique might also improve the utilization of the coal resource. ? Accordingly, the Bureau of Mines, interested in re-evaluating underground coal gasification technology in terms of current and expected conditions in the United States, requested Arthur D. Little, Inc., (ADL) to appraise the technology to determine: ? Whether the current (1971) state of the technology offers a technically feasible method for gasifying coal underground that is applicable to the reserves of bituminous and lower rank coals in the United States. ? Whether a program of research and further development of the technology could ultimately make it a technically feasible alternative to current open-pit and underground coal mining operations. ? What the nature and cost of further research and development work in the technology should be.

Jan 1, 1971

By C. B. Yu

The ore comprise of chalcopyrite, valleriite, pyrite, pyrrhotite and so on. Serpentine and talc are chief gangues. Copper phase of the tail shows that mostly valleriite be losed in tail, 70% mineral of copper is valleriite in tail, so severity reduce the recovery of copper. The traditional flow-sheet in acidity mine pulp to flotat the valleriite, but copper-sulphur separated in high alkaline pulp, so the valleriite be losed else. Explores the characters of the valleriite?s surface, studys on the flow-sheet of flotat valleriite and copper-sulphur separated. In neutral mine pulp, adopt of cationic collector to flotat valleriite, adopt of hyposulphite to depressant pyrite in low alkaline pulp can advance the recovery of copper to 5.06%.

Jan 1, 2014

By Norman A. Jull

"IntroductionThe scope of this paper is intended to deal mainly with cyclones in grinding circuits. However, the section on Cyclone Equipment, contains more general descriptions, to cover most of the cyclones used in mineral separation plants.Cyclones as heavy media separation vessels are discussed by Mark Freberg (this volume). Their use in tailings deslirning is discussed by P.C. Lighthall, eta/. (this volume).Cyclone EquipmentCyclone TerminologyApexObviously, the apex of a cone is the smallest end. However, with cyclones the term is usually used for the fitting which is attached there to control discharge of the underflow stream.Note that the cyclone need not be so mounted that the apex is the lowest point, although that is the most common method. Keeping the apex below the rest of the cyclone helps avoid plugging when the underflow contains very large particles and the tonnage of underflow solids can fluctuate.Various devices for adjusting apex diameter or otherwise controlling the underflow are discussed later under ""Cyclone Construction"".BypassingThe transport of a portion of feed slurry directly to underflow so that classification is bypassed by that portion of feed.This action is fundamental in any hydraulic classification, whether gravity or centrifugal, because the large particles going to underflow have some void volume between them, which remains filled with feed slurry.D50By definition, D50 is that particle size which has an equal probability of going to overflow or to underflow.It is calculated by drawing a curve of recovery vs particle size and noting the size at which 500Jo recovery occurs.This may be done equally with corrected or with gross recovery (see below) and the resulting value should therefore be identified as d50c (corrected d50) or as d500 (gross d50).Note also that it is common in industry practice to plot size analysis data on the retained size rather than on the average of passing and retained (the middle of the size band). To portray sizing alone it makes no difference, but to read a D50 value off a curve of corrected or gross recoveries, it is essential to plot those values on the average size of each band."

Jan 1, 1989

By C. J. Bise

In August, 1977, the Federal Surface Mining Control and Reclamation Act was signed into law [I]. It stated that: "The Congress finds and declares that because of the diversity in terrain ... and other physical conditions in areas subject to min ing operations, the primary governmental res- ponsibility for developing, authorizing, issuing, and enforcing regulations for-surface mining and reclamation operations subject to the Act should rest with the States." Section 516 of Title V (Control of the Environ mental Impacts of Surface Coal Mining) of the Act deals with the surface effects of underground coal mining operations. "Each permit issued under any approved State or Federal program pursuant to this Act and relating to underground coal mining shall re quire tfieoperator to adopt izeasures consist ent with known technology in order to prevent subsidence, causing material damage, to the extent technologically and economically feasible, maximize mine stability, and main tain the value and reasonable foreseeable use of such surface lands, except in those instances vhere the mining technology used requires planned subsidence in a predictable and controlled manner: Provided, that nothing in this subsection shall be construed to prohibit the standard method of room and pillar mining. "

Jan 1, 1980

By Fred W. Brackebush

In underground stopes that require more than minimal support, backfill is almost universally used. The term cut and fill stopingis used in a broad sense in this section, which describes underground mining methods requiring support. Support in stopes can be classified as local or short-term and general or long-term. Local support for the back of a stope, for example, can be accomplished with rock bolts or timber stulls. General support for the walls of the stope is provided by backfill. Local support provides a safe working place for the stope miners. General support, provided by backfill, preserves the access way to the stope and prevents large scale dilution of ore. Supported methods are a set of cut and fill stoping methods using backfill for general support and various local support methods. his section is subdivided into three chapters: 19.1 Cut and Fill Mining 19.2 Excavation Techniques 19.3 Backfilling Methods

Jan 1, 2008

By William N. Hale

This Bureau of Mines report gives a detailed study of water usage in the Montana mineral industries, along with projections for the future. The mineral industry of Montana in 1963 used 36.5 billion gallons of new water, and reused or recirculated an additional 53.5 billion gallons for a total water requirement or usage of 90 billion gallons. The petroleum industry was the major water user, followed by the copper and zinc industries. Many mineral industry operators provide their own water, and new water is withdrawn largely from surface sources. At present, sufficient water is available in rivers, streams, and reservoirs in Montana; however, shortages do exist locally near mineral industry operations using large quantities of water. Some is supplied from sources up to 44 miles distant. New water withdrawn by the State of Montana mineral industry is expected to increase from 36.5 billion gallons in 1963 to 51.1 billion gallons by the year 2000. The total-water requirement is expected to more than double, or reach 182 billion gallons by the year 2000.

Jan 1, 1966

By William N. Hale

This Bureau of Mines report gives a detailed study of water usage in the Montana mineral industries, along with projections for the future. The mineral industry of Montana in 1963 used 36.5 billion gallons of new water, and reused or recirculated an additional 53.5 billion gallons for a total water requirement or usage of 90 billion gallons. The petroleum industry was the major water user, followed by the copper and zinc industries. Many mineral industry operators provide their own water, and new water is withdrawn largely from surface sources. At present, sufficient water is available in rivers, streams, and reservoirs in Montana; however, shortages do exist locally near mineral industry operations using large quantities of water. Some is supplied from sources up to 44 miles distant. New water withdrawn by the State of Montana mineral industry is expected to increase from 36.5 billion gallons in 1963 to 51.1 billion gallons by the year 2000. The total-water requirement is expected to more than double, or reach 182 billion gallons by the year 2000.

Jan 1, 1966

By John Marsden

Despite the recent pullback in metal and mineral prices, and the associated market adjustments, the mining industry is still facing a serious issue with the declining availability of graduate expertise. This is due to a combination of an aging workforce, retirements and retrenchments, coupled with a lack of suitably qualified graduates entering the workforce. The issue has certainly improved since 2004 when the industry picked up the rates of hiring graduate engineers and mining/mineral school enrollments picked up in response. This hiring effort has helped to cover the ?gap? years from about 1985-2000, when industry demand for graduates was particularly poor. However, the recent market pullback is likely to set back this progress, as recruitment and hiring wavers as a result of cost cutting measures and economic uncertainty. A key issue for the mining industry is how to ensure the survival and growth of relevant ?core? degree programs. Such programs include mining, metallurgical, mineral processing and geological engineering. The mining industry needs a healthy, high-level education program to ensure an adequate supply of appropriately qualified graduates for the mining industry. Two-thirds of the professionals entering the minerals industry who graduated within the past 40 years graduated prior to 1985. Since 1985, we have been living off the legacy of graduation classes from the mid-1970s and early 1980s. It is estimated that we have been producing graduates at approximately 40 to 50 percent of the sustaining rate since about 1985. Further growth in the domestic industry would increase graduate requirements significantly, and the export of U.S.-graduates to other parts of the world (as is currently occurring) also impacts the total graduate requirements.

By G Lumley

Gold miners have been underperforming the price of gold for a number of years. So why has the æmarketÆ undervalued our gold miners relative to what they have been mining? The low valuation ascribed to gold mining companies is largely attributable to their profit performance. In the period since 2006 the price of gold in A$ has risen about $900/oz, but the real cash margin (operating cash costs + cost of finding and/or acquiring deposits + the cost of bringing them into production) has only risen about A$100. Rising operating costs are a major part of this reduction in real margin. Energy and labour costs have risen more than the inflation rates across a number of countries as have taxes, royalties, etc. There are however, more significant contributors to the rising cost base. Firstly, in 2006 the average gold grade was 2.0 g/t; today it is 1.3 g/t. Secondly, strip ratios (for surface mines) have increased by 19 per cent during this time. Open cut mining equipment unit output across the world has dropped by 26 per cent during 2006 - 2012. Finally, costs have risen by 55 per cent during this time period. Consequently, there is now 3.8 times more mining cost required to produce an ounce of gold from surface mines compared with 2006. The decline in gold grade looks to be a permanent trend as does increasing strip ratio if output is to be maintained. Costs will continue to rise although cost control will be necessary. Reversing the decline in equipment performance and closing the gap between median and best practice provides the hope for a sustainable reversal of cost increases. The current gap between best practice and median performance has grown to 112 per cent for mining trucks, 168 per cent for excavators and 169 per cent for front end loaders. Closing this gap is the potential for a more profitable future. For most gold mining companies improving mining efficiency is not an option; it is an imperative.CITATION:Lumley, G, 2013. How many gold mines will inefficiency kill?, in Proceedings World Gold 2013 , pp 267-276 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 26, 2013

By M. S. Badollet

INTRODUCTION THE DEMAND for general knowledge on asbestos fibres has increased considerably in recent years. A few publications have printed data showing some of the physical and chemical prupertie3 of asbestos, but in many cases this information is difficult to find and is seldom available when needed. During the past ten years, Johns-Manville have received many inquiries on the physical and chemical properties of asbestos fibres. Fortunately, we had some of the information in our files, and we willingly supplied the data. To help relieve this need, we have tried to present briefly in this paper some of the interesting and out-standing properties of asbestos. This information was obtained over a period of years by search of the literature and by experimental investigations. PROPERTIES OF ASBESTOS FIBRES Table I (1, 2) presents, in convenient form for easy comparison, data on the principal properties of the several varieties of commercial 'asbestos' -actinolite, amosite, anthophyllite, chrysotile, crocidolite, and tremolite. Under each variety of fibre is a brief statement describing the properties in terms of structure, mineral association, origin, etc. Some of the more important data in Table I are expanded and presented in Table II (3). SOLUBILITY OF ASBESTOS A report ( 4, 5) discussing the effects of acids and caustic on asbestos fibres was published in Germany in 1927.

Jan 1, 1951

By Wenjun Duan, Zongliang Zuo, Qingbo Yu, Qin Qin, Junxiang Liu

Moving bed has been widely used in the field of heat and mass transfer and reaction between solid particles and gas. In order to enhance the heat exchange coefficient, there will be tube banks inserted in the moving bed. In the process of drying ammoniates particles or heat recovery from high-temperature particles with moving bed, the particles flow behavior around the tube banks is significant. In this paper, the particles flow behavior around the tube banks is investigated, and all the results can provide guidance for the design and operation of a moving bed.

Jan 1, 2016

By Lewis C. Karrick, Martin J. Gavin

"Introduction.The theory of fractional ""education"" of oil from oil shale has been used by several inventors as the basis for the design of retorts for the production of oil from the oil shales of the United States. The term fractional ""education"" gives expression to the rather common belief that when an oil shales is heated it produces light, low-boiling oils as low temperatures, and increasingly heavier, higher-boiling oils as the temperature of retort¬ing rises. The theory evidently had its origin in the fact that crude petroleum may be fractionally distilled, yielding light oils at low distillation temperatures, and heavier oils as the distillation temperature increases is as, gasoline is produced from petroleum at relatively low temperatures, kerosene at higher temperature, and heavier products such as gas-oil and lubricating distillation at still higher temperatures.The writers have examined several oil-shale retorts designed to take advantage of the belief that crude, and in some cases refined, gasoline can be recovered from the shale at low temperatures; kerosene at higher temperat.res, and so on. Such retorts are usually designed to operate continuously and have several vapor-pipes lending from them at differing intervals and passing to separate condensers. Designers of such retorts repeat that the distillate from the low-temperature parts of the retort will be gasoline, and that as the shale passes to zones of increasingly higher temperatures, the vapor lines lending from these zones rill remove increasingly heavier products such as kerosene, gas-oil etc."

Mar 1, 1924

By Glenn A. Shirey

The objective of this contract as to prepare a detailed, readily usable handbook on dust control techniques for longwall mining operations. Information was gathered from available literature, and through contacts with industry and government personnel. The handbook describes those methods of dust control applicable to today's longwall mining systems, and contains sufficient design elements to assist operators with problems in testing or implementing new control procedures. Complete reference lists are presented at the end of each chapter to direct the reader to additional information.

Jan 1, 1985

By A. W. Deurbrouck

This report describes the washability characteristics of 18 coal samples taken from 11 drill hole cores from the San Juan Basin area of New Mexico and Colorado. The ash content of these coals could generally be substantially reduced by removing the heavy impurities. The coals were characteristically low in sulfur content; only one sample contained more than 1 percent sulfur after removing the sink-I.50 specific gravity material. The coals ranged in rank from subbituminous C to high volatile C; 11 of the samples were subbituminous A. Many of these core samples came from areas where very little fieldwork has been done; consequently, an outgrowth of this work has been an increase in known coal reserves of the San Juan Basin area.

Jan 1, 1972

By S Thomas, S Ricketts, R Hassell

Northern Star Resources (NSR) operates several operations utilising narrow vein stoping operations in the Kundana area. Stope dilution performance is variable across these operations, with unplanned dilution reducing individual stope economic viability, increasing risk to personnel and machinery operating in and around the stope and delaying the overall stoping sequence. Technical investigations were undertaken to objectively understand the variables which had the largest impact on stope performance and then use the findings to help develop mining strategies to reduce dilution. A stope reconciliation process was developed to compile key stope performance information such as stope design parameters, geotechnical and drill and blast factors. These were compared against the measured dilution. Production targets necessitated a high turnover of stopes in the operations, and hence a requirement for an expeditious process and mine design software with automated tools. The output of these results, together with numerical variables from geological, geotechnical and drill and blast data were analysed via multivariate regression. The analysis identified the factors with the greatest influence over stope dilution, and a forecast model was consequently created. Confidence was gained in the model when the subsequent stopes performed in line with prediction. Different drill and blast designs were subsequently trialled and found to reduce dilution. The model was then updated with the new practices, facilitating further regression analysis to identify revised key controlling factors. The subsequent production results however, displayed a poor correlation with the prediction from the revised model. Inconsistencies in drill and blast designs and execution were identified as key factors in the dilution performance. This was an important finding as the correct implementation of the design is critical and this has become a key focus for future stoping. Overall the technique presents an objective process to identify causal factors of stope dilution resulting in improved economic metrics for stope production. The process will be applied to other similar Northern Star operations.

Mar 15, 2021

By S. B. Ballantyne, D. R. Boyle

"Detailed studies have been conducted on the dispersion of uranium in stream waters and sediments around various types of mineralization and hitherto unexplained anomalous areas in the Okanagan Valley and Highland region of south-central British Columbia. These studies were part of the jointly funded and planned Federal-Provincial Uranium Reconnaissance Program of the Geological Survey of Canada and the British Columbia Ministry of Energy, Mines and Petroleum Resources. Statistical analysis of regional data indicates that U in stream waters and sediments varies considerably for different rock types, thus affecting data interpretation. In addition, the data demonstrate a poor correlation between U in stream waters and their associated sediments which can be largely accounted for by variations in climate and water and sediment composition. Regional trends in the distribution of U can be explained in terms of the above secondary factors as well as primary metallization phenomena.Significant correlations between U and F, and U and Mo can be explained by certain magmatic and mineral-forming processes. U shows little correlation with other base metals.The dispersion characteristics of U in the vicinity of Miocene "" basal type "" mineralization ; uraniferous pegmatite terranes, anomalous lineaments in granitic terranes and high-background volcano-sedimentary areas are discussed. Highly anomalous U concentrations in waters and sediments may not always be indicative of mineralization, and guidelines for interpretation require a sound knowledge of the geological and secondary processes operative in the area."

Jan 1, 1980

By Tyler Acorn, Tristan Worsey

A dozer operator at a surface gold mine accidentally drove a D10 off the side of a highwall. The blade of the dozer caught on the lip of a catch bench 60 ft. (18.3 m), down stopping its descent. The operator scrambled to safety in fear that the dozer would not hold.

Jan 1, 2014

By W. A. Forbes

OUR present-day geological surveys show that 36 of our States are underlain with bituminous coal, covering a total area of 496,709 square miles. The North American continent possesses 69 per cent of the world's coal reserves, with the United States alone having an estimated 55 per cent. The American coal reserves, in tons, are calculated to he about 3,500,000,000,000 tons, of which we have exhausted about 1 to 1 1/2 per cent. If this coal were mined at the rate of the 1918 production-a record output of 579;000,000 tons-it would not be depleted for 4,000 years. The more easily accessible and high-grade coals would obviously be consumed much before this; some estimates are 100 years. The natural progress of the nation's industries up to 1910 encouraged on every hand the development of new mines, especially where cheap and easy access to coal measures was coupled with short hauls to the consumer. Over-development resulted, which is perhaps today one of the fundamental causes for the many difficulties faced by the coal industry, which is highly competitive; about 70 per cent of the production cost is labor. Salient statistics for 1930, recently issued by the U. S. Bureau of Mines, follow:

Jan 1, 1932

By X. Cao, P. Wanjara, J. L. Fihey, X-T. Pham, F. Mirakhorli

Single-pass hybrid laser-arc welding of 10-mm thick cast plates of CA6NM, a low carbon martensitic stainless steel, was carried out in butt joint configuration using a continuous wave fiber laser at its maximum power of 5.2 kW over welding speeds ranging from 0.75 m/min to 1.2 m/min. The microstructures from the fusion zone to the heat affected zone and base metal were characterized after post-weld tempering at 600°C for 1 hour. From optical and scanning electron microscopy examination, the fusion zone was observed to mainly consist of tempered lath martensite and some residual delta-ferrite. The mechanical properties including microindentation hardness, ultimate tensile strength and Charpy impact energy were evaluated in the post-weld tempered condition and correlated to the microstructures and defects. The ultimate tensile strength and Charpy impact energy values of all the fully penetrated welds in the tempered condition were acceptable according to ASTM, ASME and industrial specifications. The failure mechanisms during tensile deformation and Charpy impact loading were examined by scanning electron microscopy, fractography and optical metallographic analysis near the fracture origin.

Jan 1, 2015