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By A Sainoki, D Fukuda, K Shioya, C Zhang, M Sharifzadeh, T Yamaguchi, S Saydam, J Kodama, C A. Amagu, Y Fuji

In an open pit mining, ensuring stability of rock slope has been one of the major challenges. As the instability of rock slopes can results in slope failures; consequently, endanger the lives of workers, affect mining operations, and often lead to economic losses. Therefore, it is practical important to study the stability of rock slopes to ensure safe, smooth, and effective mining. The stability of rock slope of about 130 m height at Higashi-shikagoe limestone quarry, which has experienced slope failures four times since 1996, was assessed. The rock mass at the quarry is consists of mainly limestone, schalstein and slate rocks intersected by clay seams of about 70 m thick at footwall of the rock slope. Previously, the effects of limestone excavation at the foot of the rock slope and shear failure due to rainfall infiltration have been investigated. Although clay is widely known to plays a vital role in the stability of slopes in engineering projects including mines, but its impacts on slope deformation at the study quarry are not adequately examined. Therefore, the present study addressed the impact of presence of clay on slope deformation at Higashi-shikagoe limestone quarry by employing both field displacement measurements and numerical simulation. Firstly, surface displacements measured by automated polar system (APS) for over eight years were analysed to understand the overall characteristics of the slope deformation. The measured results show that the displacement gradually decreases with time. The maximum displacement of about 100 mm was observed at middle of the rock slope. Secondly, the effect of deterioration and plastic behaviour of the thick clay layer were simulated using two-dimensional finite element method (2D FEM). The simulated results reveal that the clay exhibited deterioration by water contact and plastic behaviour arising from mining activities at the footwall of the clay zone. Based on the characteristics of the measured and simulated results, it was found that the displacement induced by the effect of deterioration of clay is more noticeable at the north side of the quarry whereas displacement induced by excavation is quite significant at the south side of the quarry if clay behaves as an elasto-plastic material.

Nov 29, 2022

By Pizhi Zhao, Jingwei Zhao, Zhenshan Liu, Yiheng Cao

"A new Al-Mg-Si-Zn alloy designed for automotive outer panel was trial-produced with industrial procedure. The final product shows a strong planar anisotropy. X ray diffraction analysis shows such strong anisotropy is caused by the dominating cube texture component in the final product. The reason for such high cube texture component was investigated by tracing texture evolution starting from the hot roll slab. It is found that certain cube texture components already exists in the hot rolled slab. The density of cube texture component shows as a wavy change through the following1st cold rolling, inter-annealing, 2ndcold rolling and solution treatment. This study shows that the cold rolling in the laboratory can well represent the texture evolution during the industrial production. The results obtained by lab rolling hints that change of second cold rolling reduction has weak effect on the planar anisotropy, when the gauge of hot rolled slab and final sheet are fixed.INTRODUCTIONWith the rapid progress of light-weighting in the automotive industry, aluminum sheets get more and more application as closure panel and structure parts. Recently the dominating alloy for outer panel is 6xxx series, containing the main alloy elements Mg and Si. The popular gradesareAA6016,AA6111, AA6022, and AA6014. These alloys still cannot satisfy the various requirements from automotive manufacturers. Most suppliers of automotive aluminum sheets are developing their own specific grades according to the customer’s demand. To increase the baking response, anew Al-Mg-Si-Zn alloy was designed, concerning the high combination energy between Zn solutes and vacancies formed during the quenching stage of automotive sheet manufacture. This combination is helpful to the precipitation of ß”phase during the paint baking (Wang, 2015,2016; Yan, 2014).The plastic strain ratio (r value)is a key index of the formability of automotive body sheet. A high r value means a good formability. The r values in different directions can be used to evaluate the planar anisotropy of the metal sheets. The trial produced Al-Mg-Si-Zn sheet shows a strong planar anisotropy with respect to r values. Since the r value is tightly related with texture, the texture evolution from hot roll slab (HRS) to final T4P temper was analyzed with X ray diffraction (XRD) to find the reason for the high anisotropy. Besides, the cold rolling reduction (CRR) was varied in the laboratory to modify the texture distribution, i.e., the planar anisotropy."

Jan 1, 2018

By K W. Mills, N R. P Baczynski, J Mylvaganam, D A. Prado, M F. Lee, I A. de Bruyn

"This paper presents the second part of a study of the assessment of rock stress inputs on the performance of various new mining designs at the Ok Tedi large open pit mine in Papua New Guinea. Over the years, four programs of rock stress measurement have been completed at Ok Tedi, each providing different interpretations of the in situ field stresses. Details of three of these programs and interpretations are provided in the precursor to this paper, entitled ‘Rock Stresses at Ok Tedi, Papua New Guinea’ (Lee et al, 2014).This paper explains how the various stress interpretations were utilised in the modelling of the proposed new open pit and underground mining excavations, comparing where possible their expected effects on stability. The modelled performance of three specific mine components have been discussed here as case studies, including: the below-pit drainage tunnel, as the floor of the open pit workings is mined down from 350?m above, to within just 75?m above the crown of the tunnel the stability of the 1000?m high slope of the proposed West Wall cutback the proposed sublevel open stoping extraction sequence in the Gold Coast orebody beneath the East Wall, for which only the likely ‘worst-case’ stress regime was used to assess sequencing and stability issues.The benefits of scheduling the collection of detailed rock stress measurements and other input data from a range of different sources at various stages of the projects are discussed.Alternative in situ stress models have less stability impact on open pit slopes than on underground mine excavations.CITATION:de Bruyn, I A, Baczynski, N R P, Lee, M F, Mills, K W, Mylvaganam, J, and Prado, D A, 2014. The application of rock stress inputs to stability assessments at Ok Tedi Mine, Papua New Guinea, in Proceedings AusRock 2014: Third Australasian Ground Control in Mining Conference, pp 43–54 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Nov 5, 2014

By George H. Schnakenberg

This Bureau of Mines publication describes a passive personal sampling device for N02 in air, developed by the New York University Medical Center under Bureau Grant G0133066. The sampler has been successfully demonstrated in the field and in the laboratory. In corroborative laboratory trials the agreement with reference method is excellent. The overall accuracy is approximately ±5 pct of reading to a precision of about ±l pct. All evidence indicates that these samplers should indicate the time-weighted-average N02 concentration to the above accuracy and precision equally well in the field since effects of wind velocity and relative humidity are negligible and the effects of temperature are about 0.1 pct per °F. The duration of exposure and the approximate temperature are the only data that need to be collected in the field. A two-step analysis procedure in field or service laboratory is then used to obtain the total cumulated exposure to N02 in parts per million-hours (ppm times hours), which can be converted to the time-weighted-average concentration of N02 in ppm by dividing cumulated exposure by the duration of the exposure.

Jan 1, 1976

By Stanley N. Watowich

Recently the petroleum market has made us aware that we are indeed global natural resource consumers, and as such, we have become captive to fundamental global resource economics and their attendant vagaries. Global resource supply problems are as old as civilization and mineral exploration one of its important catalysts. On the basis of natural resources empires have been expanded and new frontiers have been developed. Global consumption and production might even be viewed idealistically as a system dedicated to optimizing distribution to the consumer. However, this is not the case. Political instability and increased government polarization make dependency on a global market somewhat insecure. The U.S. must evaluate its domestic mineral re- sources on the basis that all metals are critical and that dependency on even the common and base metals may ultimately weaken our domestic economy and our potential international relationships and could cause critical weaknesses as demonstrated by the petroleum problem. This paper evaluates specifically the Duluth Gabbro Complex, of Northeastern Minnesota, (figure l), as a potential resource of critical and strategic metals. First, a chronology of some of the early exploration, will be followed by more recent intensive company studies and preliminary evaluations of economic feasibility. Lastly, metallurgical data, on some optimum conceptual mining plans will allow metal production data to be compared with an estimate of U.S. domestic needs in 1990. The purpose of this paper is to put into focus the difficulty of converting resources into vitally needed reserves.

Jan 1, 1981

By Ofori-Ansah K

The zeta potential on the surface of activated orit carbon were estimated in lhe presence of selected cations and anions that are normally associated with gold bearing ores in Kalgoorlie area of Western Australia. Additions of such ions to solution of varying pH shifted the isoelectric point of carbon from pH 4.45 to pH 7-8.3, while the anions moved Lhc isoelectric point 10 less than pH 3.2. In the presence of gold cyanide SoluLion additions of spectator ions indicated the isoelecLric poilll to be aL pH less than 3.2; the only exception was for Fe" ion where the isoelecLric point was at pH 5.9. The decrease in zeta potential appeared to be related to the counter-ions present. The decrease may also be related to the adsorption of hydroxyl ion complexes that are likely to be formed when cations are present in the solutions.Gold adsorpLion by activated orit carbon from gold cyanide solution seem to be indicated by the magnitude of zeta potential on the carbon surface. An attempt is made to relate gold adsorption and zeta potential on carbon surface with the pH of the medium.

Jan 1, 1984

By J B. Pateiro-Fernßndez, M Fuchsschwanz, G Deissmann, S Ahmad

Quang Ninh province is the most significant coal producing region in the north of Vietnam. The Nui Beo Coal Company (NBCC) operates open pit mines in Quang Ninh province and the waste overburden produced is dumped as sidehill fill in the Chinh Bac waste dump site. In the past, no special consideration has been given to the environmental impacts during the dumping operations. The mine waste is transported in trucks from the mine site to the dumping site and the loading, hauling and dumping operations are the main sources of dust emission. Rain events, especially during the rainy season, cause the generation of contaminated surface water as well as seepage of water through the dump at a number of locations. The existence of cracks at the top of the dump can pose serious stability problems with heavy rain events leading to failure of slopes which can potentially disturb vast areas of land currently used for agricultural purposes and human settlement. For sustainable development at the Chinh Bac waste dump site in the future, apart from the social and economic considerations to be assessed, there is an absolute necessity for environmental protection measures to be in place both during and after the dumping of the mine waste overburden. Research Association Mining and Environment in Vietnam (RAME) is working to develop and implement concepts for the mitigation of environmental problems emerging from dust, contaminated water and lacking slope stability to ensure successful rehabilitation of the coal mine waste dumps in the north of Vietnam. Within the framework of RAME, the Institute of Mining Engineering I (RWTH Aachen University) is managing and working to develop the stabilisation concepts for the solid mine waste dump in collaboration with the Chair of Geotechnical Engineering (RWTH Aachen University), Brenk Systemplanung and the Vietnamese group of companies VINACOMIN (Vietnam National Coal-Mineral Industries Group). The most economical and environmentally sound operations, as well as locally adaptable environmental protection measures, are essential for the sustainable development of the dumping operations at Chinh Bac dump. This paper describes the dump site and the sustainable development possibilities with an emphasis on the environmental protection and stability problems at the Chinh Bac waste dump.

Jan 1, 2009

By Clément F. Bernier

One of the chief sources of the world's supply of asbestos lies in a belt of ultrabasic rocks which runs northeastward through an area called the Eastern Townships, south of the St. Lawrence River in the Province of Québec. The productive portion of this belt extends from the town of Asbestos in the south, for a distance of some 9,5 km to beyond the village of East-Broughton. The first discovery of asbestos in this region was made in 1874. Only crude fibre was produced until 1888 when the first mill was erected near the town of Black Lake. Since the inception of the industry, almost 100 years ago, no less than 100 different compa¬nies have been formed and 46 different mines have been operated. There are presently 5 active companies in the area providing direct employment for 4100 workers, down from 6000 during the seventies.

Jan 1, 1984

By Alexander E. McHugh

A study of some variables affecting the recovery of molybdenum from oxidized molybdenum minerals was made. The effects of variations in contact time, temperature, pulp density, particle size, and solvent concentration on the recovery of molybdenum using acid and alkaline solvents were investigated. Chemical analyses, screen analyses and microscopic examinations were made and the presence of important elements determined. A hydrometallurgical method was developed to recover the molybdenum from the oxidized molybdenum ore by simultaneous dissolution of the molybdenum with sulfuric acid, adsorption on activated charcoal and flotation of the charcoal. The molybdenum was extracted from the activated charcoal with sodium hydroxide, precipitated with calcium hydroxide as calcium molybdate and this regenerated sodium hydroxide for additional stripping. A solvent extraction method, using mines, was also studied to recover molybdenum from both alkaline and acid molybdenum solutions. Satisfactory results were obtained.

Jan 1, 1967

Jan 1, 1879

By R. Rumpold

The platinum group metals (PGMs) palladium, platinum, and rhodium represent the key materials for automotive exhaust gas treatment. Since there are currently no adequate alternatives, the importance of these metals for the automotive industry is steadily rising. The high value of PGMs in spent catalysts justifies their recycling. The state-of the-art technology is to melt the ceramic carrier and collect the precious fraction in a liquid metal bath. As the feed material has quite high melting points, huge amounts of energy are required for this process. Hydrometallurgical treatments of the spent catalysts offer the possibility to recycle the PGMs with less energy and time demands. Moreover, automotive catalysts contain further valuable materials to improve the exhaust gas treatment. These compounds, like cerium oxide, cannot be recovered in pyrometallurgical processes. This paper deals with a special process that uses hydrometallurgical principles to recycle the valuable metal fraction from spent automotive catalytic converters. Hydrochloric acid in combination with hydrogen peroxide is used as leaching agent. This combination selectively dissolves the PGMs and the cerium, which can be recovered in separate steps. As the leaching solution is regenerated and reused, wastewater generation is minimized. Furthermore, the process residues constitute potential byproducts.

Jan 1, 2012

The lignites of Otago and Southland offer a potentially viable future feedstock for electricity production and possible conversion to petrochemicals or liquid fuels. The deposits, when combined, represent New ZealandÆs largest energy inventory; equivalent to about 74 000 petajoules û or approximately 35 times current natural gas reserves. Too often dismissed as irrelevant to New ZealandÆs energy future because of adverse perceptions of the value of low rank coals, the strategic value of this resource is in fact huge.   Investigations of the lignites extend back over more than 50 years (LFTB various, CRL Energy Ltd). Whilst it is not the intention of this paper to review this work, these investigations have confirmed the suitability of the resource as a feedstock for thermochemical conversion. Current estimates of South Island lignite mining costs are NZ$1.0 - 3.0/GJ (Natusch 2005), making these resources amongst the most competitively-priced energy sources available world-wide.   This value, however, will only be captured if we as a country begin to envisage a world-scale, long-life, integrated and multi-faceted development sized to supply world markets for chemicals or fuels. Recent CAE studies (Hooper and Riddolls, 2005) have emphasised the vital importance of ensuring that any exploitation of this resource maximises their value to New Zealand. The question that thus must be applied is how might large-scale utilisation of the resource fit with New ZealandÆs primary energy supply, and its potential for the export of high-value commodities.   From the broader perspective of New ZealandÆs total energy supply equation we need to examine other supply options beyond just the generation of electricity. We face in this country a situation wherein almost all our liquid fuels feedstock has to be imported with projections for an increasing dependence on imported oil. In addition NZ has a natural gas reserves-to-production ratio of less than ten years, and dwindling supply from local production. Without further natural gas discoveries, New Zealand has only a window of approximately five years before we will need to commit to imported LNG or some other thermal fuels option.   In other words, New Zealand is facing an uncertain future unless we can restore energy inventories to cover an adequate strategic reserve capacity as well as enable long-term investment in alternative sources. Within this context the South Island lignite resources are thus deserving of more attention. The extent of the resource is well known, its suitability for conversion reasonably assessed, and its magnitude such that there is little doubt that lignite conversion could adequately meet NZÆs future energy needs for many years out.   This paper reviews coal gasification technology, its application to lignite and the possibilities for future development of the lignite resources. It is argued that the strategic imperative for this country is to secure the lignite resources as a primary energy source for this country well into the latter half of this century.

Jan 1, 2005

By Robert Roby

The Mouat copper-nickel deposit in Stillwater County, south-central Montana, was examined by Paul T. Allsman, an engineer of the Bureau of Mines, in 1939. Because of the strategic importance of nickel, a project was executed by John East, Jr., J. J. Naughton, and E. W. Newman, engineers of the Bureau, to further delimit some of the copper-nickel sulfide-bearing bodies that had been discovered by the Anaconda Copper Mining. Co. in 1937 and to investigate the central part of the deposit, which had not been drilled previously. This report is based largely upon the results of the. Bureau of Mines investigation and the results of exploration by the Anaconda Copper Mining Co. In addition, a brief description is given of some other copper-nickel sulfide-bearing deposits along tho Stillwater Complex.

Jan 1, 1949

By Gary L. Hundley

The Bureau of Mines has devised a procedure to recover chromium chemicals from low-grade domestic chromites, which contain silicon and aluminum impurity levels that are too high to permit processing by present industrial processes. The Bureau procedure consists of reacting chromite with molten sodium hydroxide (NaOH) under oxidizing conditions to form sodium chromate (Na2Cr04). The reaction product is leached with methanol to remove the majority of the unreacted sodium hydroxide, then with water to remove the sodium chromate and the remainder of the sodium hydroxide. The sodium chromate product is recovered by evaporative crystallization from the aqueous solution. This report presents results of laboratory tests to determine the optimum fusion conditions and the chromium extractions obtained from several domestic chrotdte concentrates. These concentrates are from a variety of sources, including the Stillwater Complex in Montana, Kanuti River-Caribou Mountain, Red Bluff Bay, Kenai Peninsula, and Kodiak Island areas in Alaska, deposits in northern California, and a nickel-cobalt laterite from southern Oregon. All of these concentrates were successfully treated by the Bureau procedure. The best chromium extrac-tions obtained for each of these materials ranged from 69.5 to 98.9 pet.

Jan 1, 1985

By W. D. Riley

The Bureau of Mines is conducting research on methods for the rapid identification and sorting of mixed scrap metals and alloys so that domestic scrap resources can be fully utilized. One method, spark testing, is the examination of the pattern of sparks that results when a metal or alloy is ground on an abrasive wheel. This technique requires experienced sorters. Bureau researchers have shown that spectrophotometric methods can be used in lieu of the highly skilled sorter. The spectra of a mild steel, an HSLA steel, several stainless steels, and four nickel-base alloys have been measured. Differences in the spectra that are sufficient for identification are apparent.

Jan 1, 1985

By R. B. Mears, G. F. Sagar, R. H. Brown

There are well recognized procedures for determining the various tensile, fatigue, and other mechanical properties of the common structural materials. This makes it possible for engineers to design structures of various materials which have adequate initial strength to stand the stresses to which they are subjected in service. There is also considerable general information about protective measures suitable for protecting the usual structural materials from the effects of ordinary environments. However, often insufficient quantitative information is available on the combined effects of stress and corrosion to permit the designer satisfactorily to appraise the structure from the stress-corrosion standpoint. This situation is further complicated by the fact that the stresses causing stress¬corrosion failures are usually not the design stresses but rather the residual forming and assembly stresses which are generally of unknown magnitudes. Thus, tests which will rapidly evaluate the susceptibility of materials to stress-cor¬rosion failures are extremely useful. Of particular value are tests which can be applied to built-up structures as well as to simple specimens, since, as mentioned above, residual stresses often are caused by fabricating procedures and assembly operations. The present paper contains

Jan 1, 1945

The New Southern Railway (NSR) involves the excavation of approximately 10 km of single bore tunnel from Tempe Reserve, Tempe, to Prince Alfred Park (PAP). PAP is located just south of Central Railway Station in SydneyÆs Central Business District (CBD). From Tempe Reserve the alignment takes the tunnel under Sydney Airport including the main north/south runway. Sydney Airport is approximately 8 km south of the CBD. The NSR is being constructed by a private group, the Transfield Bouygues Joint Venture (TBJV). Transfield is a major Australian contractor and the French contractor, Bouygues, is providing the soft ground tunnel construction expertise and is also responsible for the design of the concrete segmental lining. This paper sets out to present in some detail the issues involved in tunnelling under the airport and in particular under the north apron, the main north/south runway and the new elevated roadway. The paper concentrates on these three areas on the airport with an emphasis on the following. The risks involved and measures taken to minimise the risks in tunnelling under the International Terminal north apron (with Jumbo Jets parked immediately above). Secondly, settlement predictions, settlement and runway operation criteria and the actual settlements that have occurred on the main north/south runway. Finally, the criteria that was developed during the construction of the deep bored piers for the elevated roadway at the Domestic Terminal as the TBM passed through this area of construction activity.

Jan 1, 1999

By Arne Landsberg

The Bureau of Mines has undertaken research to elucidate the chemistry involved in the efficient recovery and control of minor elements in base metal smelting operations. These elements should be effectively recovered not only because they have commercial value, but also because of their potential hazard to workers' health and the environment, if they are not controlled during processing. Cadmium, a minor metal in zinc ores, is the subject of this report. The roasting step of the complex zinc-smelting process was chosen for investigation because of the high potential for removing cadmium by volatilization during this primary stage. Commercial roaster feed materials were used to determine the sequence of reactions and the effect of these reactions on the volatilization of cadmium. Electron microprobe examination of both the commercial roaster product and oxidized sulfide solid solutions prepared in the laboratory showed that oxidized iron was of prime importance in preventing cadmium volatilization. The mechanism by which iron prevents cadmium volatilization is proposed, and a preheating technique is recommended for more effectively recovering cadmium prior to roasting.

Jan 1, 1981

By Adolfo Pillihuaman Zambrano

Fe-Cr-C production is a very high electrical energy consuming process. Decrease up to 10% of this electrical energy is expected when self-reducing agglomerates are used. This research aims to understand how the synergetic effects are when stronger reductant, like Fe-Si, is substituted for coke in self reducing pellets. Brazilian chromites containing 41.2%Cr2O3 were mixed with petroleum coke and agglomerated with cement as the binder. Small amounts of 1%, 2% and 4% of Fe-75%Si were substituted for the equivalent petroleum coke, and pure silica plus hydrated lime were added for adjusting the slag composition. The mixture was pelletized, dried and submitted at 1773K up to complete the reactions. The results showed that the reduction reactions were 1.4 and 2 times faster with 1% and 2%Fe-Si addition, respectively, than with no addition. The microscopic analysis showed that it was formed a liquid phase, but the pellet did not collapse what indicates that the coalescence of the metallic phase depends on the dissolution of the pre-reduced particles of the chromites into slag.

Jan 1, 2008

A 1991 survey of 48 mining companies, employing more than 24 000 employees, showed that disabling injury and disease rates continue to be the most common measurements of safety management effectivness in the Australian mining industry.Of the companies surveyed, 22 claimed to be making regular safety audits. Of these only two listed the improvement of audit scores among their goals for 1991.Influenced by loss control management thinking, some managers have expanded the scope of their safety programs to include all accidental operational losses adversely affecting mine profitability.Learning from their new experience with total quality management some managers are now recognising that successful safety management outcomes depend on the effective management of program inputs. They are thus turning away from measurements of accident consequences - the failures of the management system - to measurements of management control.The new focus of safety management attention is now on corrective actions before accidents happen.

Jan 1, 1992