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By AIME

After an adventurous past-four changes of government in thirty years -the whole of Silesia and attached coal territories have become part of the Polish State. The coal resources of this area are the biggest among the European countries. Under a surface area of 5700 sq km are about 100 coal seams, with a total thickness of 150 meters. According to German estimates, there are some 150 billion metric tons of coal ranging in thickness up to 14 m within a depth of 1500 m. The seams are mostly level, free from faults, with good top and bottom; the coal is of excellent quality, hard and clean; and mining conditions are favorable. The mines are worked at considerable depth by means of vertical shafts and operate with cage and skip hoisting. Before the war, the mines were up to date, equipped with modern machines. Among the European countries, output per man shift was the highest ? 1.9 to 2.1 metric tons ? and cost of production was the lowest.

Jan 1, 1949

By F. J. Sotillo

Mineral processing requires good classification of particles to attain an adequate separation of minerals. This is of utmost importance in the case of sulfide minerals. An ideal classification is obtained when particles are separated at a given mesh, which is fixed according to the characteristics of each sulfide ore. Under these ideal conditions, particles coarser than the mesh of separation are recovered in the underflow, whereas particles finer than the mesh of separation are recovered in the overflow. This paper presents the results of pilot plant tests that were performed on Ag-Pb-Zn and on Ag-Au Peruvian sulfide ores using a Density Separator, and the comparison of these results with those obtained using hydrocyclones, under similar operating conditions. The results show that the ratio of circulating load is reduced by 50% by using a Density Separator with respect to that obtained by using hydrocyclones. Moreover, the effect of the improvement in the separation efficiency obtained by using the Density Separator on the kinetics of flotation is also shown. Silver recovery of the Ag-Pb-Zn ore increased by 18% whereas gold grade in the concentrate of the Ag-Au ore is doubled.

Jan 1, 1998

By G Britton, P Moynagh

As more than a few mines gradually sink under the weight of emails, whiteboards, notice boards and ever more complex spreadsheets, the holy grail of effective short-term interval planning and control in underground mines is as far away as ever. Despite the mining industry investing ever greater amounts in planning and Enterprise Resource Planning systems, short-term plans become ever more complex and rigid. What the industry desperately needs are not more ‘disembodied voices down the speaking tubes’, but flexible and effective planning systems that encourage people to make reasonable commitments to each other so that everyone can work as a coordinated team to complete the work required each shift.One solution to the challenge has emerged. This paper describes the ‘Fewzion’ shift planning and short interval control system which has been developed at Anglo American’s Moranbah North and Glencore’s Oaky Creek coalmines in Central Queensland. Fewzion has drawn on management theory embodied in Management Operating Systems, Lean and Theory of Constraints approaches to continuous improvement to play a key role in both mines achieving record breaking tonnages.In addition to explaining the Fewzion approach, a case study is presented describing how Anglo American’s Moranbah North improved production by 39 per cent in 2014/2015 and won ‘Coalmine of the Year’ two out of the last four years and how Glencore’s Oaky Creek sustainably improved monthly development meters by 34 per cent within two months of implementing Fewzion.CITATION:Moynagh, P and Britton, G, 2017. How a frontline planning and commitment system improves trust, commitment and results in operations, in Proceedings 13th AusIMM Underground Operators’ Conference 2017, pp 235–240 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Oct 16, 2017

By Steven C. Torma

The present article reviews some of the technologies available for recycling high-energy yield explosives loaded projectiles. These activities lead to reduction of military ammunition stockpiles and their conversion into commercial and industrial applications. The recycling technologies involve dismantling and separation of ammunition components into recyclable metals, plastics, paper and explosive materials. The metal 1 ic components will be sent to smelters, where they will be converted to products that can be used in a variety of industries, such as construction, automotive, housing and so on. Plastics and paper will be recycled and reused. Explosives will be recycled to be used for industrial purposes in the mining industry. Propellants (ammonium nitrate and ammonium perchlorate) can be ground to small particle size and treated to be used in the agricultural industry as fertilizer. In addition, some of the excess explosive material recovered in the demilitarization process may be incinerated to produce energy for steam production for heating purposes, or for production of electricity. Furthermore, this article reviews the developments in the bioremediation of explosive contaminated soils and industrial effluents.

Jan 1, 1994

By Pizhi Zhao, Yingdong Li, Hailong Cao, Yingjuan Feng

"Three types of anodic films (unsealed, hot water sealed and agent sealed) were prepared to study the effects of anodizing pores structure on the adhesive bonding performance of AA5754 automotive sheets. The morphology of the anodic films was examined by using scanning electron microscope (SEM) and the composition was examined by glow discharge optical emission spectroscopy (GDOES). The adhesive bonding strength and durability in corrosive environment were investigated by using single lap shear test and salt spray corrosion test (SST), respectively. The results showed that the pores structure could significantly influence the adhesive bonding performance. The unsealed sample showed porous structure and provided high bonding strength, however, the durability was poor in corrosive environment. The hot water sealed sample showed fine and loose hydrated alumin a structure on the surface and provided high durability in corrosive environment, but the bonding strength was low. In contrast, the agent sealed sample provided both high bonding strength and durability in corrosive environment.INTRODUCTIONAdhesively bonded aluminum joints by using adhesives have been widely used for the realization of lightweight design in industrial applications like automotive and aerospace industry[1, 2]. Durable bonds which are capable of taking structural loads can be created due to a careful consideration of the way in which the joint is formed, the type of adhesive and the appropriate treatment of the adherend surfaces prior to bonding[3-6]. Experiences demonstrate that the surface treatment is the most critical step which could not be disregarded, since it is essential to achieve long-term service capability [7].In structural applications, a bonded assembly is expected to maintain a significant load and may be combined with exposure to harsh environmental conditions in its service life. For this purpose, the pretreatment for structural bonding of aluminum alloy must provide not only strong tensile strength and durability but also good corrosion resistance. Chromic acid anodizing (CAA) process provides an anodized layer which has good corrosion resistance while also exhibiting useful adhesion characteristics as well as lacquer coating retaining characteristics[8].However, the use of Cr (VI) is unadvised from a health and environmental point of view since it is toxic and carcinogenic, and this process is gradually limited even prohibited. Boeing's phosphoric acid anodizing(PAA) process provides a more open pore structure allowing penetration of high molecular primers/adhesives[8]and PAA process is the most widely used pre-surface treatment suitable for adhesive bonding between aluminum alloy components. Rahimi et al. demonstrated that nanostructure can be produced by PAA process and is affected by the time of pretreatment and anodizing parameters [9]. Xu et al.investigated the influence of surface energy and roughness on adhesive bonding through PAAprocess and provided improved adhesion performance under certain anodizing parameter[10]. However, PAA process is normally not recommended for a major concern of deterioration of the mechanical performance of the joints as a result of exposure to a wet and corrosive environment. Sulfuric acid anodizing(SAA)process, recently, has been widely used for corrosion protection and good base coating for the adhesion of lacquers in aerospace manufacturing[11]. The good performance is explained by properties such as the porous morphology and high adsorptive power of the oxide film, the chemical and electrical inertness of the anodized layer. Moreover, modified sulfuric acid could also used for adhesive bonding. Lunder et al. found that anodizing in hot sulfuric acid is promising as a simple, very rapid and environmentally friendly pre-treatment for adhesive bonding[12].Saeedikhani et al. studied the process of phosphoric/boric/sulfuric acids anodizing and found it was is a promising pre-treatment for adhesive bon"

Jan 1, 2018

By Seth C. Scharfer

"As part of the Bureau of Mines effort to provide thermodynamic data for the advancement of mineral technology, the Gibbs energies of formation of MoS2 (molybdenite) and WS2 (tungsten disulfide) were determined with high-temperature galvanic cells employing stabilized Zr02 (zirconia) as the electro¬lyte. In the temperature range from 867 to 1,209 K, potential measurements were obtained for the cellPt, MoS2 , Mo02 , SO2 = 1 atm // Zr02 // 02 = 0.0112 atm, Pt, with the overall cell reactionMoS2(c) + 3 02(g, 0.0112 atm) = Mo02 (c) + 2 S02(g). (1)These results, combined with the best available values for Gibbs energies of formation (?G°f) of Mo02 (molybdenum dioxide) and SO2 (sulfur dioxide) from the literature, give the standard Gibbs energy of formation of MoS2, ?G°f, for the reactionMo(c) + S2(g) = MoS2(c) (2)?G°f = -96.681 + 43.76 x 10-3T±0.538 kcal/mole, (3)where temperature (T) is expressed in Kelvins.Similar measurements in the temperature range from 872 to 1,210 K were obtained for the cellPt, WS2 , W03 , SO2 = 1 atm // Zr02 // 02 = 0.0114 atm, Pt, with the overall cell reactionWS2(c) + 3.5 02(g, 0.0114 atm) = W03 (c)+ 2 S02(g). (4) Combination of these results with the best available data of ?G°f for W03 (tungsten trioxide) and SO2 from the literature gives the Gibbs energy of formation of WS2 in the temperature range from 872 to 1,210 K for the reactionW(c) + S2(g) = WS2 (c)(5)?G°f = -92.429 + 43.88 x 10-3T ± 0.280 kcal/mole. (6)A third-law analysis yields a standard enthalpy (?H°f) for the reaction298Mo(c) + 2 S(rh) = MoS2(c), (7)?H°f = -67.36±0.60 kcal/mole, (8)298where the standard states are pure crystalline MoS2 / and rhombic sulfur."

Jan 1, 1980

By Alfred Goldberg

The paper is founded on the results of an investigation on the softening behavior of a cold-rolled low carbon steel. This specimen, originally cold rolled 15 , 30 , 50 and 75% reduction in thickness, were annealed at several temperatures ranging from 481 to 687ªC. A temperature-time range was encountered over which strong competition between these processes was evident. An interpretation on the effect of test variable on determining which one of the competing processes dominated during annealing is presented.

Jul 20, 1961

A combination of the needs of business, employee desires and safety and health considerations is stimulating increasing attention to the time spent by people at work and the timing of that work. Particularly we are seeing: - innovative work schedules for 24-hour mining businesses; and - response from industry to accommodate the needs, even the desires, of employees in return for systems which are more productive and more capital efficient. There appears to be an evolutionary trend for business management to become more sophisticated and responsive to the need for achieving close to best cost work schedules to sustain continuous improvement. The underlying motivating forces driving this trend for improved techniques in organising attendance at, and time spent at work, is the seemingly inseparable combination of technological advance and ever-increasing accumulation of capital. The mining industry has not remained untouched by this thrust for ever-increasing need for best use of labour, to adopt advances in technology and to provide attractive opportunities for putting accumulated capital to work. An essential component of this on-going thrust is a substantial effort by the mining industry to improve the performance of labour by providing most-productive work schedules.

Jan 1, 1996

By John R. Duda

The Bureau of Mines is developing estimates of capital investment, operating cost, and selling price for underground mines producing bituminous coal by various mining methods. This study estimates the required capital investment, operating costs, and selling prices for two hypothetical mines designed to produce 1.3 and 2.6 million tons per year (MM tpy)3 by using a longwall system in conjunction with a continuous-mining system. The coal properties being mined are assumed capable of sustaining a 20-year production period. Wages and union welfare payments used in this study are those in effect as of December 6, 1975, as set forth under the National Bituminous Coal Wage Agreement of 1974. Costs of materials and equipment are based on January 1976 indexes. Initial capital investment is $34.6 million for the 1.3-MM-tpy mine and $63.5 million for the 2.6-MM-tpy mine. Capital requirements, including deferred investments, were estimated to be $50.8 and $92.2 million, respectively. These figures translate into total capital investments of $38.51 and $34.91 per ton of annual production. Assuming a desired 15-percent discounted cash flow (DCF) rate of return, with Federal income taxes at 50 percent, the required selling prices would be $13.41 and $12.27 per ton for the 1.3- and 2.6 -MM- tpy mines.

Jan 1, 1976

By J. Norman Bulkley

As electrical power is used to a greater extent on the Rand than in any other mining center, it is thought that a short description of the methods used and results obtained may be of interest. In comparing Rand practice with that on other fields, several general factors should be borne in mind: First, the mines are all working on large tonnages of low-grade ore (average. $6.50). The annual crushing rate is about 27,000,000 tons. Second, the mines are all grouped udder the financial and engineering control of mining houses, so that the results of a group, rather than an individual mine, are open for study, and practice follows more uniform lines. Third, coal of fair quality (about 12,000 B.t.u.) can be obtained for $2 to $3 per ton., Good supplies of condensing water are, however, scarce, and have to be carefully stored. Power Supply Power is supplied by the Victoria Falls & Transvaal Power Co., Ltd., and its subsidiary, the Rand Mines Power Supply Co. Both companies, which are practically one from an engineering point of view, operate the following stations, all feeding into the same system.

Jan 2, 1916

By Edmund S. Leaver

[In previous reports 5/ of ore-testing studies standard methods of conduction tests with precious-metal ores selected as representative of certain mining districts were discussed in considerable detail.]

Jan 1, 1941

By Groom P.

The wastage of timber in coal-mines that is caused by decay is very great; in fact, far greater in this country than is generally realized. Mr. E. W. Peters estimates that of the whole wastage of timber in mines in the United States of America, 50 per cent, is due to decay and insects; of this 50 per cent, an overwhelming part is due to decay. The most efficient methods of decreasing this grave loss can be devised only by co-operation of the mining engineer and the scientific expert, and it is partly in the hope of procuring such collaboration that this paper is written. It contains, therefore, a resume of our present knowledge of the decay of wood, and of the economic methods of checking this in mines; but, with a view to improving those methods, it also directs attention to the gaps in our knowledge and the means by which these can be filled by future investigation

Dec 1, 1916

By A Galley, M Plouffe, T Hynes

Canadian mining research has recently been reinvigorated through a pan-Canadian research strategy driven by the industry, the research community and government departments. These organisations have come together to form the Canada Mining Innovation Council, whose role is to focus and increase mining research in the country. One of the major themes of the organisation is environment; including major research initiatives on energy, tailings and environmental stewardship. Other major initiatives on exploration, mineral extraction and mineral processing will also consider environmental benefits in the research projects they undertake. All the initiatives have their priorities determined principally by the mining and exploration companies, whose first obligation is to determine the long-term research priorities of the industry as a whole, rather than for their individual companies. Only after industry consensus on priorities does the research community become engaged in the implementation of specific projects to address those identified priorities. A goal of the program is to effectively create a virtual mining research laboratory, by engaging all the major research centres in the country. Membership to date includes most of the major mining companies operating in Canada and almost all of the mining-related universities. Other members include federal, provincial and territorial governments, consulting and service companies and manufacturers.CITATION:Hynes, T, Plouffe, M and Galley, A, 2012. A new approach to mining research in Canada, in Proceedings Life-of-Mine 2012 , pp 333-338 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 10, 2012

By François Martin, Roland Plassart, François Laigle

"MOTIVATION The storage of nuclear waste gives rise to a lot of innovative issues for underground space technologies. The nuclear activity of waste generates temperature effects on both the lining and the surrounding rock mass. In order to avoid these unfavorable effects, the number of waste containers is controlled in the gallery section. The galleries section has consequently ranged from a diameter of 4 to 6 meters. However, in the case of intermediate-level nuclear waste, due to the lower temperature, the number of containers in a cross section of a gallery is assumed to be safely increased. Despite technical difficulties, a large diameter gallery (typically 12m excavated) seems to be more cost effective. This paper demonstrate the feasibility of such a gallery in the specific context of CIGEO (French Geological Repository Project for nuclear waste), located in the Bure area in the north-eastern of France. The geology of Bure at the project’s depth (about 520 meters) consists in a quite homogeneous layer of Callovo-Oxfordian argillites (COx argillites). With such an overburden, this rock is known to have a high plastic behavior with significant time-dependent effects. These mechanical properties require complex behavior laws in computational modeling used for the design of underground facilities.EXPERIENCE OF LARGE DIAMETER GALLERIES In order to identify some specificities in the design of such openings, a research has been run on existing galleries of large diameter (more than 10 meters), like the tunnel of Chamoise, Lötschberg, Tartaiguille or Saint-Martin-La-Porte. Two of these representative examples are detailed hereafter. Tunnel of Chamoise (French Jura) In spite of a lighter overburden (400m versus 520m), an anisotropic initial stress state and a variable rate of carbonates, the highway tunnel of Chamoise is quite similar to the planned gallery for intermediate-level nuclear waste, with a geology very close to the CIGEO’s one in some sections. Because the northern tube encountered difficulties during the excavation a few years before (several over-excavations and spalling, especially in the bench), the excavation of the southern tube has been carried out in two steps, but with a high bench and a small curved invert (Figure 1). The design of the immediate support consists in long bolts and a shotcrete layer. The concrete lining is about 50cm thick."

Jan 1, 2016

By R. E. Lindstrom

The mineral bastnasite is utilized to describe alternate processes for the extraction and separation of the rare-earth elements by solvent extraction. The rare earths can be acid-leached directly or fused with NaOH before acid leaching. Cerium, the major constituent, can be recovered by fractional precipitation, fractional leaching, or solvent extraction with tri-nbutyl phosphate. The latter process is capable of producing 99.5-percent pure CeO2 at 98+ percent recovery. Lanthanum is subsequently recovered by fractional precipitation or solvent extraction with a nitrogen-based extractant. A 20-stage mixer-settler operation with a primary amine extractant results in a 95-percent pure La203 fraction at 96 percent recovery. Europium is amenable to extraction from most of the remaining rare earths with an organophosphate extractant. Selective stripping of the europium, followed by reductive precipitation, produces high-purity Eu203. Another possibility for europium purification involves the differential extraction of europium with an amine followed by a sub- sequent reducing strip. Separation of the remaining elements is more difficult but can be accomplished with amine or quaternary ammonium extracts. Typical separation factors achieved are 3. 8 for praseodymium-neodymium and 10. 5 for neodymium-samarium.

Jan 1, 1967

By Christopher C. Jobes

Computer-aided control of a mining machine requires a guidance system to aid remote positioning of the machine by determining its position and heading. The mechanical position and heading system (MPHS) developed by the U.S. Bureau of Mines provides such navigation information during face maneuvers. This report describes the required theory, which yielded a reliable algorithm for calculating machine position and heading, and implementation of this theory in hardware and software design, which made surface testing of the MPHS possible. Analysis of the errors and test results showed that the MPHS provides reliable results and can, therefore, provide useful guidance information for face navigation.

Jan 1, 2010

By S H. Li, H Z. Gu, A Huang

High aluminium steel is a promising advanced steel known for its exception properties and holds significant economic and strategic importance. However, the CaO-Al2O3-SiO2 based slag with high alumina content reacts vigorously with alumina refractories during the smelting process at high temperature, seriously affecting the safe and efficient production of furnaces and resulting in the formation of Al2O3-MgO non-metallic inclusions within the molten steel. This is a bottleneck problem for high-quality steel refining, and the key reaction path during the corrosion remains unclear. The dissolution reaction mechanism of alumina refractories in high alumina CaO-Al2O3-SiO2 slags under a weak static magnetic field was investigated in this work, using high temperature laser confocal microscopy and in situ radiation spectroscopy techniques. The results indicate that the interaction between the high alumina slags and the alumina refractories is governed by free radical reactions. The dissolution of alumina forms AlO and AlO2 radicals. The reaction rate increases with the C/S ratio of the slag due to its low polymerisation. The reaction between non-bridging oxygen and AlO2 free radicals accelerates the generation of AlO and O2ꞏ- radicals. The reaction layer composed of calcium aluminate is formed through the recombination of AlO, Caꞏ+ and O2ꞏ- radicals. The weak static magnetic field induces the Zeeman splitting of free radical pairs and intersystem crossing occurs, promoting the formation of triplet free radical pairs through the hyper-fine coupling effect. The reaction can be significantly inhibited as the triplet free radical pair does not meet Pauli’s incompatibility principle. This discovery perfects the structure theory of molten slags with radicals and provides supplement to the design of the highly slag-resistant refractories, and provides the theoretical basis for the development of external field protection technologies for high-quality steel refining.

Jun 19, 2024

By L. V. Bell

THE object in prospecting is to find ore. With the exception of certain discoveries of more or less accidental nature, intelligent prospecting as conducted today is, whether consciously or not, based upon a process of elimination. In the following discuss on it is proposed to evaluate those factors that enter into the eliminating of certain tracts of ground and, conyersely, the concentrating of attention upon others. The danger of generalizations as to the barrenness of cer.ain areas, without having due regard for all such factors, is emphasized. The fact that our conception as to what areas or rock formations are to be regarded as favourable or unfavourable is, in some measure at least, changing with new discoveries under diverse and unexpected circumstances, adds more point to the discussion. The criticism might be raised that the subject is treated largely from the standpoint of geology, but that may be met by stating that it is, and must continue to remain, precisely from this standpoint that the prospecror directs his activities. Briefly, the geologist may render the greatest service to the prospector in the early steps of selecting (a) the general territory in which to prospect; (b) the area to be intensively prospected; and, finally, (c) those parts of the claim or claims to be prospected in detail. Although certain phases of the discussion will be, in some measure, of general application, we shall here concern ourselves essentially with prospecting in the pre-Cambrian shield. Furthermore, the subject is so large that it has been decided to limit it to a consideration of that portion of the pre-Cambrian rocks in which is situated the mining district of western Quebec, of which the writer can speak with more personal knowledge. This limitation need not, however, seriously detract from whatever merit the discussion may possess, since the deposits concerned cover a fairly wide range of metallic ores, including gold, copper with associated zinc, and, lastly, molybdenum.

Jan 1, 1936

By Robert L. Marovelli

Organizational development that attempts to simultaneously deal both with training and with job design parameters as they relate to mine health and safety, productivity, and quality of life is one of several areas of research that the Bureau of Mines is pursuing. The Bureau sees potential in this particular effort for reducing accidents and injuries, improving worker satisfaction and health, and increasing productivity.

Jan 1, 1981

By Maria I. De Rosa

The U. S. Bureau of Mines performed experiments to determine if the primary gas toxicities evolved during the early (~300° C) and later (~400° C) combustion stages of chlorinated polyester-reinforced mine ventilation ducts could be predicted by a smoke particle characteristic, for the development of a test parameter. The experiments were conducted in an approximately 20-L furnace, at 14-min durations at set furnace temperatures of 2500 and 1,000° C, with an airflow through the furnace of 10 L/min. The variables studied, as a function of time, were the hydrogen chloride (HCI), carbon monoxide (CO), carbon dioxide (C02), and oxygen (02) concentrations, furnace temperatures, the sample mass weight loss, the average smoke particle diameter (dg and average number and concentration (no), and the product of the average smoke particle diameter and concentration (dgno). Results show that the inverse of the smoke particle diameter-concentration product [(l/dgn0)], correlates directly and significantly with the primary gas toxicities evolved during both early (HCI) and later (CO) stages of combustion.

Jan 1, 1989