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Analysis of rock discontinuities, collected using a scanline method, has been undertaken at the Iron Duke open cut mine, on the southern margin of the Middleback Range in the Gawler Craton, South Australia. The iron mineralisation, which is a product of supergene enrichment of carbonate sediments, is located on the W (western) limb of a gently N plunging D2 macrosyncline. Mesofolds plunge shallowly to the NE or steeply to SE, suggesting two shortening events, of which the second produced significant macrofolds. Discontinuities include:faults and shears which display variable orientations, mainly striking WNW dipping steeply N; mesofractures or joints maintaining a well constrained orientation, dipping steeply S, subvertical striking E-W; and bedding surfaces which are folded about a gently N plunging axis. Through this example of the regional control exerted on local discontinuities, it is clear that discontinuities are not randomly distributed as often assumed in purely statistical approaches. Commonly for rocks of any age there is a distinct discontinuity pattern, reflecting the geological deformation history. If the controls exerted on local rock discontinuities can be determined and assigned a number related to their significance, the way forward is available to develop a site specifc knowledge base that can make realistic predictions for any position in a given rock mass. Such a procedure would involve assessment of the regional geology, linked to scanned discontinuities either via manual or automatic means. Recent advances in automatic scanning rock faces (eg by the I-SiTE Laser Radar) to determine discontinuities distributions, enable the rapid calculation of rock characteristics. This is a significant advance in rock engineering, providing a method of safe and quick collection of data. However it creates problems in the presence of an increase in the geotechnical data available, which should be assessed in the context of the regional geology. Although techniques are underway to analyse post-blast discontinuities, the next signifant potential advance in this area could be the integration of a knowledge based system to assess discontinuities ahead of mining, incorporating regional assessment and human intuition.

Jan 1, 2000

By A. O. Orumwense

Mill circumferential speed, the number of passes of pulp through the grinding chamber, media type, size and filling ratio were investigated in an attempt to determine how to effectively grind copper concentrates in a stirred mill. The stirred mill product fineness was enhanced to some extent by decreasing media size, high media filling, and an increased number of passes of the pulp through the grinding chamber. Shape also plays a major role in grinding media effectiveness, with spherically shaped media producing a finer size. The fineness of the product increases with increasing power consumption but the method of energy transfer is very important in energy utilization. The effect of the mill parameters on copper flotation was evaluated. Copper recovery was influenced by grinding media size, mill speed and the number of pulp passes through the grinding chamber.

Jan 1, 2006

By James A. Pendleton

In response to Public Law 95-87 (SMCRA), Colorado promulgated regulations governing the mining of Coal. These regulations require the prediction, monitoring and mitigation of "material damage" caused by subsidence. All permitted underground coal mines within Colorado have approved subsidence programs. Preliminary monitoring results indicate the subsidence mechanical predictions have been sufficiently accurate to preclude material subsidence damage. The State of Colorado has developed a practical approach to regulating subsidence, which stresses monitoring verification of predicted subsidence phenomena. However, shortcomings exist in our ability to precisely predict the secondary consequences of subsidence, including effects to structures, the hydrologic balance and the environment. Lack of accuracy in predicting these secondary consequences results in uncertainty, necessitating conservatism in permitting. To avoid increasingly stringent permit restrictions, future research should emphasize the secondary consequences of subsidence.

Jan 1, 1986

By Paul J. Ehret

With the passage of the Surface Mining Control and Reclamation Act (SMCRA), and the implementation of state permanent programs, underground coal mining operations are for the first time subject to government regulations regarding subsidence. These regulations now and in the future will directly affect the manner in which mining companies mine their coal. Since the promulgation of the original final regulations by OSM, numerous changes in those regulations have been made and many additional changes are pending in the near future. This paper will discuss state and federal approaches to regulating underground coal mines and examine issues surrounding future subsidence regulations.

Jan 1, 1986

By R. Dillinger

In the environmentally conscious social atmosphere today, reclamation in surface mines has become a main issue to the public and the regulatory committees. In response to this increased attention, many regulatory committees have begun to enact more stringent regulations on surface mining operations. Operations across all spectrums of the industry have seen changes. Recently and most visibly the mountain top removal mines have seen several new regulations focusing on environmental protection. Specifically regulatory committees have emphasized a focus on the methods of reclamation and recovery of layers suitable for vegetation. These layers are the most visible once the operation has concluded. Also, these layers have the most human interaction (farming, hunting, and house development). Often times the new regulations enacted are shifting from a performance base to a standards base. The key differentiator being a performance base dictates the final result while a standards base dictates the method to achieve the result. The very nature of many regulations (especially those that are standards based) not only challenges the physical limitations of the equipment used today, they come with a financial impact. For the purpose of this paper, the model will be a surface coal operation, utilizing draglines as primary overburden movers. The coal seam is ten feet thick, the overburden ninety five feet thick, the pits are 150 feet wide, and the dragline is a Bucyrus Erie 1570.

Jan 1, 2011

By Jeffrey D. Thatcher, Debra W. Struhsacker

With the burgeoning development of precious metals heap leach mining projects throughout the country regulatory agencies are beginning to take a closer look at the short-and long-term environmental consequences of heap leach mining. This increase in regulatory review is occurring on federal, state and local levels, and is affecting both large- and small-scale mining developments. Small-scale mining developments are receiving especially critical regulatory scrutiny because in the eyes of some regulatory agencies, small developers lack the credibility automatically accorded to major mining companies. This is due in part to a bad image of small miners based upon past environmental problems and permit violations caused by a few, small operators. The proponent of a small mining development thus faces special problems during the project permitting process, and must convince the regulatory authorities of his company's ability and commitment to plan, develop, and decommission a mining operation in compliance with environmental regulations. Not only must the small developer have a thorough understanding of the regulatory requirements affecting his project, he must also devote considerable effort to careful internal planning in order to produce a well organized approach to project permitting. The importance of proper planning cannot be overstated. Project planning is key to convincing the regulatory agencies that the small miner is capable of developing a viable project. More- over, the economics of a small mining project demand permit acquisition at modest cost and in a timely fashion. A well planned permitting effort will thus ensure that permits are received within budget and on schedule. This paper will review the federal, state, and local permitting requirements for heap leach projects, and the variability of these requirements from state to state. The environmental assessment process for projects developed on public lands, and the acquisition of zero- discharge water quality permits, air quality permits, and local special use permits as they apply to small mining developments will be discussed. The paper will conclude with a review of project decommissioning and cyanide neutralization requirements and their implications for small-scale heap leach projects.

Jan 1, 1987

By A. Bothma

The Impala No. 1A ventilation shaft is located approximately 15 kms north of Rustenburg and is accessed via the R510road from Rustenburg to Northam/Thabazimbi. This situation is shown on the location plan in Figure 1. The geology at the site consists of an upper layer of black turf of about 1 metre in thickness, grading into weathered norite. The depth of weathering is generally less than 5 metres. Zones of deeper weathering may occur along fracture zones associated with faults and dykes. Groundwater occurs mainly within the weathered/fractured aquifer system. The ventilation shaft is a 5.1 m diameter upcast shaft ,and forms part of a system of ventilation shafts to complement the existing infrastructure as mining progresses down the new twin decline extension of Impala 1 shaft. The principal reason for these shafts is to lessen the risk of an extended RAW and also to counter the effects of the heat build-up as the mining goes deeper, with the resultant effect that the existing cooling centre (fridge plant) becomes more remote from activities. The No. 1A shaft (upcast) is positioned approximately 1,2 km on down dip from the main shaft and the No. 1Bshaft (downcast) approximately 1,2 km further. Geological information was used from a borehole 1,2 km away on strike from the upcast shaft. The first shaft (1A) is a 5,1 m diameter hole to be fitted with two 2,2 MW fans, whilst the second shaft (1B) is 4,1 m diameter to accommodate a 7MW fridge plant.

Jan 1, 2001

By Gungor Tuncer, Ali Kahriman, Abdulkadir Karadogan, Umit Ozer, Kagan Ozdemir

In the condition that drilling and blasting technique is inevitable depending on the rock mass and material characteristics on mining activities, the fragmentation rate and particle size distribution of the muckpile after blasting has important influences on the performance of subsequent mining activities such as loading, hauling, crushing, grinding etc. and the total costs of that mine. Drilling and blasting is an important step in this process chain and it's results such as fragmentation, muckpile shape and looseness, dilution, damage and rock softening effect the efficiency of downstream processes. There is an increasing body of blasting research indicating significant impacts in these downstream processes.

Jan 1, 2007

The Cowarra gold mine is at latitude 36°O'S. and longitude 149°19'E. which is roughly 20 miles north-north-east of Cooma.The deposit was· originally worked towards the end of the last century, but the presence of sulphides associated with the gold in the primary zone caused cessation of work when that zone was reached.GEOLOGY AND MINERALIZATIONThe principal country rocks are sandstones and shales of Silurian and Ordovician age, both very strongly folded with structural pitches ranging from a few degrees to almost vertical. The mine proper is within Silurian rocks and the main orebody (there are several minor parallel bodies) is developed within a shear striking approximately north, dipping approximately 70° east, and ranging in width from 2 ft to 15 ft but averaging about 4 ft.This shear is impregnated with quartz and sulphides with which the gold is associated. The predominant sulphide is pyrite though pyrrhotite is commonly present in quantity.Arsenopyrite and bornite are present in smaller amounts.Stillwell (1936, 1937a, 1937b, 1938, 1941) has published five mineragraphic reports on the ore.The various levels have been mapped in detail (Figs. 1-3) and the No. 2 level plan (Fig. 1) shows the general relationship of shearing, as now indicated by mineralization, and faulting. There is no apparent connection between the fold structures and mineralization.Fig. 3 is a longitudinal projection showing the distribution of gold expressed as inch-ounces. The estimation of...

Jan 1, 1965

By Paul Foote

MOST of the treatises on metallurgy intimate that simultaneously with the development by the atomic physicist of a really satisfactory theory of the atom will be inaugurated a new epoch in the science of metals. Metallurgically and metaphorically, we shall dwell in the Utopia of Sir Thomas More. It is my privilege this afternoon to demonstrate that this state has not arrived. An atom is a miniature planetary system consisting of a positively charged nuclear sun about which revolve electrons each carrying the negative charge e. The charge on the nucleus is + Ze where Z is the atomic number and the number of planetary electrons in a neutral atom is equal to Z. These electrons are arranged in several groups having different binding energies. Ordinary x-ray phenomena relate to processes occurring deep within the atom, usually with electrons in the so-called K or L shells. Such electrons in the heavier atoms are so closely bound to the nucleus that the forces exerted by neighboring atoms in a solid are relatively inappreciable. For most practical x-ray investigation, the atom may, be considered as in the gaseous phase completely isolated from its neighbors. The K radiation from an element in the gaseous state, in the solid or liquid phase, or even in combination with other elements in all its possible valences, is almost identical. ? Visual and ultraviolet spectroscopy is concerned with disturbances of the most loosely, bound outer or valence electrons of the atom, always in the vapor state. The remarkable progress of the last year in both theo-

Jan 2, 1926

By J. W. Halley, G. L. Plimpton

BECAUSE of the two distinct stages in the solidification of rimmed steel, segregation in the rimmed ingot is more complex than that in the killed or semikilled ingot. In the earlier stage, chemical reactions, resulting in evolution of gas and vigorous stirring of the metal, effect a degree of negative segregation unique to rimmed steel. The composition of this zone constitutes the principal quality advantage of this type of steel. In the later stage of solidification, after the evolution of gas has ceased, the segregation follows the general pattern of a more completely deoxidized steel. However, the composition of the liquid remaining after the first solidification stage varies markedly from that of the original melt, some constituents having been partially removed as reaction products while the concentration of others has been intensified by rejection from the metal solidifying in the first zone. The aim, from the standpoint of segregation, in rimmed steel of high quality is to effect a maximum negative segregation in the rim zone without excessive concentration of undesirable elements at the center of the ingot. To achieve this aim, the composition of the melt may be varied and the furnace and pouring practice may be adjusted within certain limits. It is the purpose of this study to discuss segregation in rimmed steel from the standpoint of the mechanisms that produce it and to survey the phases of open-hearth practice that influence those mechanisms. MECHANISMS PRODUCING SEGREGATION The mechanisms that determine the degree of segregation in the rimmed ingot are closely interrelated, making it difficult to select the primary factors and to determine a satisfactory order for presenting them. For instance, the question of sulphur segregation is relatively simple, since sulphur is not directly involved in chemical reactions in the ingot; but its concentration in the rim zone is dependent not only on its original analysis in the melt, its segregation coefficient, and the freezing rate, but also on the rate of its removal from the impure film on the solidifying surface. This washing action involves all the factors (such as freezing rate, the carbon-oxygen product, pressure, etc.) that determine the rate of gas evolution and hence the efficiency of film removal. Sulphur distribution between the rim and core is affected by the volumetric ratio between the two zones, and its segregation in the core is a function not only of the freezing rate of the core but also of all the foregoing factors that determine its concentration in the metal when solidification of the core starts. To simplify the presentation, it is proposed to treat the mechanisms affecting segregation independently in this section, reserving a discussion of their over-all effects for the section in which actual segregation data are given. The factors affecting segregation will be treated in the following order: (I) differential solidification, (2) removal of constituents as

Jan 1, 1944

The area (330 sq. miles) shown on the map of the Brocks Creek District (Fig. 1), was mapped by the Northern Territory geological party of the Aerial, Geological and Geophysical Survey of Northern Australia. This work was done in two stages:-(i) In 1935, an area of 30 sq. miles around the Golden Dyke mine was mapped by P. S. Hossfeld, Senior Geologist, and A. H. Voisey, Assistant Geologist. The results were described in a detailed report (10).(ii) In 1939, an area of 300 sq. miles in the Brocks Creek district was mapped by C. J. Sullivan (Senior Assistant Geologist), and V. M. Cottle and S. N. Kiek (Assistant Geologists) under the general supervision of P. S. Hossfeld (Senior Geologist).An outline structural map, together with some geological notes was published (1), but that map does not show the amphibolites, and the relationship between ore occurrence and general geology is not emphasised. The publication of the detailed maps and reportwas postponed indefinitely as a result of war. The original mapping was based on air photographs with a scale of approximately 1 in. to 1,200 ft., and all detail which could be shown at that scale was mapped. Features recorded included rock types, details of structure, mineralisation, and surface workings, creeks and soil boundaries. Underground mapping was also carried out. The present map is much simplified from the original, but it is hoped that it shows sufficient information to reveal close relationship between structure, granite, sills of amphibolite and gold occurrence. About 50 per cent. of the area is covered by deep soil or alluvium, and in these portions the geology of the underlying rocks was not determined with accuracy, though in many places strike trends could be deduced from air photographs.Because the A.G. & G.S.N.A. had published the geological notes and map referred to above, and because the publication of the detailed report and maps is still postponed indefinitely, approval has been given by the Bureau of Mineral Resources, Geology and Geophysics (which took over the affairs of the A.G. & G.S.N.A. at the termination of its operations) to the preparation of the present paper so that information would be available to the public.The views expressed in this report are those of author. The results of the investigation suggest that in areas where granites are predominantly concordant with bedding, ore deposits may be found at approximately the same stratigraphic horizon. It is thus important to correlate beds even though their relationship may have been obscured by faulting and folding.

Jan 1, 1950

By Stanislaus Skowronski

OVERPOLED copper, as commonly defined, is copper which has been excessively reduced during the poling period of the refining process. Owing to its porosity, such copper is unfit for commercial purposes. The cause of this phenomenon is undoubtedly the lack of oxides in the copper, yet this does not completely explain it. Refined copper of the same "pitch" and "set" varies considerably in oxygen contents, and analyses of overpoled bars also show similar wide differences; moreover, it is possible to melt copper in crucibles so as to obtain bars that are practically free from oxygen although they show a "tough pitch" and "level set" surface. Frederick Johnson advances the following theory: The regulation of the quantity of oxygen in copper is the keynote of all copper refining. It is the presence of a Well defined proportion of oxygen in the form of cuprous oxide, forming a copper-cuprous oxide eutectic, Which enables copper to be cast free from blowholes. It seems that When oxygen is present, other gases are less soluble in molten copper; When oxygen is absent, or is present in insufficient quantity, the copper dissolves other gases, such as hydrogen and carbon monoxide, Which are insoluble in the copper when solid, and, being rejected during the process of solidification, causes internal porosity and external ridges and excrescences.1 The "level set" of Wire bars, etc., is entirely the result of a compromise between the occluded gases and cuprous oxide. With excess of the former the metal would be "overpitch" and spongy, While an excess of the latter would result in the metal being "underpitch" and brittle.2 The result of the absorption and subsequent expulsion of reducing gases, carbon monoxide and hydrogen, and the effect of this action. on the overpoling of copper are in dispute; the literature on the subject is full of contradictory statements and will continue to be so until better analytical methods have been developed. Sulphur, however, is tangible. The refiner can see it in his button sample and consequently attributes to it any trouble that may happen during the melting of the copper.

Jan 3, 1918

By Lachezar Tsotsorkov

Corporate social responsibility Is a principal trend of the corporate strategy for sustainable development of Assarel-Medet JSC ? the largest Bulgarian company for open pit mining and ore processing the production activities of which date back to 1964. Sustainable development Social responsibility is considered as one of the three pillars for sustainable development, together with the economic and environmental responsibility.

Aug 1, 2013

By Cang Daqiang, Bai Hao, Li Ning, Liu Xueting, Lu Xin, Zhao Lihua, Li Hongxu, Wei Wei

"Based on the principle of carbon balance, a model was built to calculate C02 emissions of each process and correspondingly the total course of production in iron and steel making. The data from a typical integrated steelworks in China was applied in the model. The results show that the BF and coking process account for the most emissions. Generally, C02 emissions in integrated steelworks depend on three factors, resources utilization efficiency, energy utilization efficiency and energy consumption structure, which were considered in an equation in this paper. Especially, General Emission Factor (GEF) was proposed to assess the relationship between C02 emissions and energy consumption. The results show that, higher GEF will result in more C02 emissions with the same energy consumption and in iron and steel making, the optimization of energy structure and development of eco-industrial park both have significant benefit on the carbon reduction.IntroductionThe Global Warming resulting from the increase of Greenhouse Gases (GHGs), especially C02, in the atmosphere has become the main reason of global climate change, and the carbon reduction is one of the most important ways for the sustainable development [1]. The iron and steel making is a manufacturing industry based on iron-coal high temperature chemical process, in which plenty of C02 is emitted. According to the data from IPCC (Intergovernmental Panel on Climate Change) in 2001, iron and steel making emitted about 650 million tons ofC02 every year, which is the fourth largest industry of the fossil energy consumption [2]. According to the data from EEA (European Enviromnent Agency) in 2006, iron and steel making is the largest source ofC02 emissions, which accounted for about 18% of the total C02 emissions in European manufacturing industry [3].It is estimated that the application of various well developed energy-saving technology, such as Coke Dry Quenching (CDQ), Top Pressure Recovery Turbine (TRT) and Coal Moisture Control (CMC), can make the C02 emissions reduced by 0.5%-3% in iron and steel making, and the further C02 emissions reduction can be achieved if more new energy saving technology is applied, such as sintering plant heat recovery, electricity generation with steam generated from converter and the various by-products gas and the hydrogen making process from COG[4,5]. In addition, the application of membrane separation technology is well expected in iron and steel making [6]. For example, the application of C02 Capture and Storage (CCS) in blast furnace combined with the Pure Oxygen Top Gas Recycled BF (TGRBF) technology can reduce the C02 ennss10ns greatly by about 50%-60% [4].That is, as a kind of C02 end-treatment technology, CCS applied with other technology of C02 recovery would be more meaningful. Actually, reduction of the C02 emissions by changing the structure of energy consumption and raw materials with new process of iron and steel making, such as direct reduction process or smelting reduction process [4,7,8], is the trend of ferrous metallurgical engineering, which is regarded as a kind of source-treatment technology. In this sense, source-treatment technology is more pivotal for the solution of carbon reduction in the future than the current popular energy saving technology. Hence, it is necessary to build the C02 emissions model based on the iron and steel making process and evaluate the relationship between the energy saving and C02 emission reduction."

Jan 1, 2012

By A Maldonado, A Robert, K G. Mercer

The Hamersley Group in the Pilbara, Western Australia, consist of interlayered banded iron formation (BIF) and shale host rock formations within which a large number of open pit iron ore mines have been established. The slope stability of most of the mining excavations developed within these formations is controlled by the relatively low shear strength of the shale groups and shale bands, which are the weakest rock types. Shale formations range from fresh to highly weathered and are generally highly fissile when fresh, and clayey when weathered. An accurate understanding of the shear strength of these materials across the entire weathering continuum is therefore a key importance for assessing the slope stability of these mines.Historically defect laboratory testing results for the Pilbara mines have been analysed mechanically using direct shear testing (DST) to measure a number of geotechnical characteristics of the rock bedding and defects. This paper sets out the current practice in the industry in terms of the laboratory testing and presents a possible application of hyperspectral data to empirically correlate the shear strength of shale bedding with the relative mineralogy abundance on the bedding surface. This was achieved by creating both hyperspectral and geotechnical data sets for the same samples.In the study the shale samples were separated into three distinct assemblages: iron oxide + kaolinite, iron oxide + white mica + kaolinite, white mica + kaolinite, which had 40, nine and two samples respectively. Analysing these assemblages alongside DST data showed that samples with white mica had reduced non-variable shear strength, whereas samples with iron oxide + kaolinite had an overall higher shear strength but with a greater variance. It is inferred that the reduced shear strength in the white mica samples is due to the sheet (or plate) like structure of the mineral, giving it a weak stress plane. Confidence in the trends observed can be reinforced by expanding the data set in future works. The investigation also includes a discussion on weathering grade and addresses the question as to whether mineralogy abundances influence these characteristics in Hamersley shales.CITATION:Maldonado, A, Mercer, K G and Robert, A, 2017. The relationship between mineralogy and shear strength of Pilbara Hamersley Group shales across the weathering spectrum, in Proceedings Iron Ore 2017, pp 423–430 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 24, 2017

By Paul Cameron Gilmour

Geologically, as distinct from economically, "porphyry copper (molybdenum, gold, silver, etc.) deposits" might be defined as large, disseminated and/or stock-work occurrences of copper-minerals, generally averaging less than 1 per cent cop-per. They are normally associated with small plutons which range in composition from granite to diorite, although, typically, they consist of quartz monzonite or granodiorite. Circumstantial evidence indicates that these "minor" granitic intrusions may represent the intrusive phases of post-orogenic, calc-alkaline volcanism, this conclusion being suggested by: 1. Texture and grain size. 2. Prevalence of intrusive breccias. 3. Relationship to unconformities and estimated depth of emplacement. 4. Spatial distribution in relation to orogenic zones. 5. Age of mineralization and igneous episodes

Jan 1, 1972

By Luis Pommier

The requirements of metals by modern society have created big challenges for mining engineers minerals processing engineers, metallurgical engineers and economists to produce these metals economically from mineral deposits which contain, with time, less and less value. The advances of science and technology allow, today, the exploitation of mineral deposits which only few years ago would not have been considered economical. However, there are limitations both on the minimum grade of recoverable values contained in the ore to be fed to a mill or on the concentrate to be smelted, and on the maximum content of "impurities" i.e. chemical elements which are difficult or expensive to refine from the ore, from the concentrate or from the metal. It is also known that the cost of treatment in a mill or in a smelter, for unit of metal contained in the ore or in the concentrate, increases as the grade of the recoverable values contained in them decreases and also if the content of impurities increases. In order to work a mineral deposit economically it is necessary to ensure not only that it has more than a minimum content of values, less than a maximum content of impurities and that there exists a good up-grading or metallurgical process but also to ensure that the opti-

Jan 1, 1971

Slake durability of rocks is an important property of rock-mass and rock-materials in geotechnical practice. The slake durability of rocks is closely related to their mechanical properties. In this paper, mechanical properties and slake durability tests for weak and clay-bearing rocks from Beypazari Trona Bed in Ankara, were performed in order to assess the slake durability and mechanical properties (especially rock strength) of these rocks as well as to understand the relationship between mechanical properties and slake durability. In performing this relationship, statistical based correlation has been applied.

Jan 1, 2003

By S. Luyckx

This paper reports hardness and abrasive wear resistance test results from a wide range of WC-Co alloys, varying in cobalt content as well as WC grain size. The results show that the abrasive wear resistance increases with increasing hardness and that the rate of increase is higher for larger WC grain sizes. The increase in abrasive wear resistance was found to be parabolic up to a critical hardness value and exponential above that value. The transition from parabolic to exponential behaviour was found to occur at the same contiguity value for all grain sizes, which suggests that at that contiguity value the WC skeleton becomes continuous in all WC-Co alloys.

Jan 1, 2004