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By F. E. Bedale

STUDY of several severe mine explosions that occurred during the winter of 1907 led to the belief that coal dust was a definite explosion hazard. The Consolidation Coal Co. was a pioneer in the early work to' eliminate this hazard and to combat the dangers incident to poor ventilation and the presence of methane. Maintenance of high humidity throughout the mines was one of the first measures adopted, later to be superseded by rock-dusting. In the twenty years from 1907 on, many safety measures were developed and adopted, and several prizes were won, though the practice was crude by present-day standards. But in 1927, the company went to work in earnest, and organized a Department of Safety with adequate personnel and with authority to enforce all approved rules for the prevention of accidents and the preservation of company property. All plans for new construction work, changes in mining systems, and proposals for the purchase of new mining equipment had to receive the approval of this Department. A set of operating- and safety standards was written to govern the activities of all employees, and physical examinations for them were required.

Jan 1, 1938

By B Rouvray, R Bertuzzi

The development of a design-and-construct tunnelling project in Australia from its concept to its construction requires designs to be prepared and reviewed at several distinct stages prior to documenting ‘for construction’. On recent projects the post-tender stages have been variously called 30 per cent—70 per cent—100 per cent; or concept–substantial–final; or system definition–preliminary–critical. The design is reviewed at each stage by the designer’s internal reviewer, the contractor and its independent advisor(s), the owner and its independent advisor(s), the project’s independent certifier, proof engineers and often third-party stakeholders and their advisors. Documentation for each stage often dominates the design effort, at times distracting from design. This paper presents the authors’ experience of this design-and-review process. Comparisons of design budget and actual design spend and design program implications are presented. It is postulated that a subtle change has occurred in our industry that has diminished the value of the design dollar. Is there a better process? An alternative is suggested.CITATION:Bertuzzi, R and Rouvray, B, 2014. Reducing the cost of tunnel design in Australia, in Proceedings 15th Australasian Tunnelling Conference 2014 , pp 501–506 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 17, 2014

By R. H. Fewkes

New information on possible resource value of sea floor manganese nodule deposits in the eastern North Pacific has been obtained by study of records and collections of the 1972 Sea Scope Expedition. Nodule abundance (percent of sea floor covered) varies greatly, to judge from bottom photographs from 8 stations and data from other sources. All estimates considered reliable are plotted on a map of the region. Similar maps show the average content of Ni, Cu, Mn, and Co at 89 stations from which 3 or more nodules were analyzed. Variations in nodule metal content at each station are shown graphically in an appendix, where data on nodule sizes are also given. Results of new analyses of 420 nodules from 93 stations, for Mn, Fe, Ni, Cu, Co, and Zn, are listed in another appendix. Relatively high Ni+Cu content is restricted chiefly to four groups of stations in the equatorial region, where group averages are 1.86, 1.99, 2.47, and 2255 weight percent. These and a few other areas may warrant more exploration. It is hoped that this report will stimulate new interest in North Pacific nodule deposits and that the maps and quantitative data will aid future exploration.

Jan 1, 1981

By A. J. Naldrett

"Synorogenic mafic intrusions are a common feature of the northern Appalachians. Two sulphide-bearing intrusions in central Maine that have been investigated revealed a number of important features that illustrate sulphide-silicate interaction that relates to magmatic sulphides. The Moxie Pluton is a large mafic intrusion emplaced during the Devonian Acadian orogeny. The Katahdin gabbro is a small mafic body that is probably genetically and temporally related to the Moxie Pluton. Both intrusions were formed bv the intrusion of variably fractionated magmas into irregular chambers and feeder zones. The southern half of the Moxie Pluton contains three small sulphide accumulations, whereas the Katahdin gabbro hosts a large, predominantly massive, sulphide body. Textural evidence clearly documents the magmatic origin of these sulphides.The three Moxie Pluton sulphide bodies are located at or very close to the intersection between the intrusion and the sulphidebearing Hildreths Formation. Sulphur assimilation, suggested by this relationship, is supported by the isotopically light (634S = —8 to —25) and the selenium-poor (S/Se - 25 000-48 000) character of the Moxie sulphides and correlation with the Hildreths Formation sulphides (S34S = —25, S/Se = 25 000-48 000). Isotopically light sulphur (534S = —20 to —21) and high S/Se ratios indicate that the majority of sulphur in the Katahdin sulphide body was also derived from an unexposed country rock source. The volume of sulphide in this example illustrates the potential efficiency of the sulphur assimilation process—so efficient in this case that marked dilution of the economic chalcophile elements resulted from the addition of so much external sulphur.The three Moxie Pluton sulphide occurrences are all impoverished in Ni and Cu (1.87-0.44% Ni; 0.72—0.32% Cu in massive sulphide), but contain normal Co contents (0.22-0.13%) relative to typical magmatic sulphides. The Katahdin sulphides show a greater Ni and Cu impoverishment (0.2% Ni; 0.1% Cu in massive sulphide) with similar Co (0.17%). The Ni content of the Moxie Pluton olivines document the fractional removal of sulphides during crystallization of the host magma, which resulted in the progressive depletion of the chalcophile metals in this magma. Modelling that involved the fractional crystallization of the magma coupled with the fractional removal of a specified proportion of sulphide has successfully duplicated the Moxie Pluton sulphide compositions. A similar magmatic model has been postulated for the Katahdin sulphides with a greater degree of sulphide fractionation. This latter model is again supported by extremely low Ni/forsterite ratios in olivines, though the compositional range is insufficient to document fractionation. These magmatic models are not unique, but they provide a relatively constrained and consistent explanation for the sulphide compositions.The Ni contents of olivines are the most important indicator of sulphide-silicate interaction in mafic magmas and have exploration potential. They provide a means of assessing the timing and extent of sulphur saturation in an intrusion and are a guide to the Ni content of a sulphide accumulation in equilibrium with olivine. In the Maine examples they provide strong evidence of the magmatic origin of the sulphide accumulations and justification for magmatic modelling."

Jan 1, 1984

By J. Larsson

In the pursuit of increased safety the mining industry has worked to develop systems for remote control and autonomous operation of both stationary and mobile equipment. This paper reports on a newly developed system for teleoperation and autonomous tramming of LHD (Load-Haul-Dump) mining vehicles that not only increases the safety of the operators, but also has the potential to increase productivity.

Jan 1, 2010

By C. D. Iles

The philosophy used in designing and writing Duval's Sierrita mine design programs is discussed. The Sierrita Incremental Design system (SID) is reviewed with emphasis on Pushback Extraction Design (PED). FED is a method by which predesigned pushbacks are sequenced into an optimized period-by-period design that can be directly utilized in daily operations as well as intermediate and long range planning. The advantage of SID is that it provides a practical, mineable open pit design. PED is not a theoretical design system; it is in operational use.

Jan 1, 1981

By N. R. Thote, J. L. Porathur, C. P. Verma

Highwall mining is a highly mechanized coal mining method associated with several advantages, such as a very high production rate (approximately 3,000 t/d) and low production costs. There is no requirement for underground support, ventilation, or blasting. Production leads to added recovery, which is otherwise lost in the ultimate pit. The use of highwall mining can bridge the gap that exists between supply and demand in the energy sector. This paper presents a brief review of highwall mining technology, including current status, analysis tools, and design techniques. In addition, it identifies important parameters from the analysis of failure case studies.

Jan 1, 2014

By D. Berkley

The competitive pressure, the increasing energy costs and the environmental regulations impose substantial challenges to the definition of power plants serving industrial facilities. Primary mining and metallurgical facilities have even greater challenges because they are often located remotely, where the fuel supply can be a problem. The absence of a power grid imposes challenges on the reliability and quality of the electrical energy supply. In addition, the facilities usually require thermal energy too, not only electricity. This paper outlines these types of issues that have to be considered when defining a cogeneration plant integrated with a remote located industrial facility. It is addressed to the ?users? of cogeneration facilities rather than to ?generators.? The focus is on analyzing various site-specific design considerations to pre-screen the feasible cogeneration alternatives and minimize the number of options to be analyzed from the economics viewpoint. This approach could substantially reduce the engineering effort and schedule during the feasibility phase of the project. Part 1 of this paper (Berkley, 2003) provides a basic understanding of cogeneration plants of various types to establish a common language. Part 2 outlines and analyzes specific issues that could be of help in the definition of cogeneration installations for remotely located industrial facilities, with a focus on mining and primary metallurgical plants.

Mar 1, 2003

By Henry P. Cole

A comprehensive review of published research was carried out to identify methods for teaching and assessing critical but nonroutine skills needed for coping with emergency situations. Specific methods for assessing critical skills proficiency in aviation, medicine, organization management, the military, and other industrial/technical workplaces are described. The potential application of these methods for teaching and assessing (1) critical first aid and (2) self-rescue and escape skills to underground coal miners in annual refresher training is explored. Research and development activities that may improve mine health and safety training are suggested. Most of these research and development activities were completed later in the project. This additional work is reported in the project technical report #2 and the final report. The research reported in the present document was completed in 1984 -85. Many of the initial findings reported in this document are updated in the later project final report.

Jan 1, 1988

By Donald B. Gillies

PROBABLY the most critical and difficult period in an engineer's career is that between the completion of his college work and his attainment of professional recognition and accepted status in the industrial world. Upon leaving school the young graduate breaks his immediate ties with his educational institution and in a sense finds himself adrift. At this time in his life a society like our Institute has both the responsibility and the privilege of meeting a vitally important need in his professional life. Some of these young men are Student Associates, in the year after graduation, and some are Junior Members, but all need advice and assistance. In some respects this situation will be accentuated by the war. Not only will thousands of young engineers be mustered out of military service but the process we describe generally as industrial reconversion will make necessary many readjustments in personnel. About two years ago the Institute recognized the opportunity of helping the younger member to help himself by appointing a new standing committee to be known as the Committee on Professional Development of Junior Engineers. Herbert Hoover is Honorary Chairman and it is my privilege to serve as Chairman. The name of the Committee is not entirely satisfactory but it expresses the general objective. The present article is in the nature of a progress report of the work of this Committee.

Jan 1, 1945

By P. G. Semple

For the last four years, the Kilborn Group of Companies has been involved in several major projects in the Confederation of Independent States (CIS). These include the Kumtor project, the Kubaka gold project, the Kazgold project, the Aginskoe project and the Jerooy project. These projects are all in various stages of detailed engineering and construction. Western mining companies are pursuing mining opportunities throughout the world in search of ore bodies for development. The quest for profitable mining ventures has led mining companies to South America and Asia and, more recently, to the former Soviet Union. When considering the CIS, several factors should be considered. The most notable are geography, mining culture and previous mining production.

Jan 1, 1996

By M. J. Voigt, R. A. Govender, A. Mainza, L. Bbosa

"Mineral texture is a critical factor which controls ore variability and is an important attribute in geometallurgy. In relation to downstream processes, it affects the fracture pattern during breakage, where rock strength is inherently a function of mineral texture. Because of the subjective nature of mineral texture, it has not been easy to quantify, especially in the context of a measurement suitable for use in geometallurgical programmes. The aim of this paper is to present the first steps in developing a 3D mineral texture quantification method for drill core and to assess its sensitivity to differences in rock strength using a case study. The methodology includes classifying the textural information using the 3D grey level co-occurrence matrices (GLCM) and X-ray computed tomography (XCT) coupled method. Rock strength tests were performed using the split Hopkinson pressure bar (SHPB). The case study investigates a heterogeneous polymetallic sulphide deposit and a homogeneous shale subdivided into three ’mineral textural types’. The variability is largely captured by the GLCM matrices, and preliminary trends can be observed where the shale is finer grained and has a higher yield strength in comparison with the coarser grained polymetallic sulphide ore. IntroductionModern mining requires the exploitation of lower grade and more complex, heterogeneous orebodies to address the growing industry demands. Historically, processing plants were designed and built based on average ore characteristics and therefore are relatively inflexible when facing the full spectrum of ore variability in heterogeneous orebodies (Lamberg, 2011; Lotter, 2011; Schouwstra et al., 2013). The practice of geometallurgy represents an opportunity to manage ore variability in the mining industry (Powell 2013; Baum, 2014; Yildirim et al., 2014; Nguyen, 2013). It focuses on quantifying the relationships between ore characteristics and their downstream mining and processing responses, often starting with small-scale laboratory testing. The purpose of geometallurgy is linked to maximizing the net present value (NPV) of an orebody by minimizing technical and operational risk – where ‘ore variability’ is considered one of the most significant technical risks."

Apr 1, 2019

By J. F. Wright

During the last three years prospecting has been active in southeastern Manitoba and a number of interesting gold, nickel and copper deposits have been discovered within an area 90 miles north of the international boundary, and extending about 40 miles westerly from between mileage 60 and 110 on the Manitoba-Ontario boundary. As known at present, two-thirds of this area of 2,000 square miles is underlain by pre Cambrian granite and granite gneiss and is not likely to contain mineral deposits of economic importance. The remaining one-third is underlain by metamorphosed sediments and lavas (greenstones), penetrated by the granite and granite gneiss and, at various localities, cut by bosses, sills, or dykes of gabbro, diorite, granodiorite, and other types of intrusives. The nickel, copper, and gold mineralization accompanied or followed the intrusion of these different rock types. The gold deposits are limited in distribution, so far as known, to the northern part of this prospecting area and occur along Manigotagan and Wanipigow rivers. These deposits have recently been described in some detail, (3) and therefore only the copper and copper-nickel deposits of the southern part of this area, along Oiseau and Maskwa rivers, will be described in this paper.

Jan 1, 1925

By Florence L. Feicht, Carlton E. Brown

"INTRODUCTION This report contains information on the approximate size of the smallest dust Particles revealed by or the limit of visibility of various microscopic systems. The information was obtained mainly for use in interpreting and evaluating results of number-contentration and particle-size, determinations on, samples of unhygienic particulate matter collected from industrial atmospheres and in developing better methods for determinations nations.Some speculation and even controversy have been published on the limit of visibility of the widely used microscopic system (16-mm., 0.25-or 0.3-N.A. objective, and axial light-field illumination) used in counting the dust in the liquid medium from impinger, 4/ 5/ filter-paper, 6/ and other samples, but little or no quantitative data have been published on the limits of visibility of this or other microscopic' system.ACKNOWLEDGMENTSThe interest, encouragement, and assistance received from H. H. Schrenk, chief of the Health Division are gratefully acknowledged, as is all other assistance received in this study."

Aug 1, 1945

By A. Ducastel, S. Connemann, A. Stark, F. Bouillot, C. Fricke-Begemann, LSA, H. Knapp, L. Horckmans

"Refractory materials are essential for all high-temperature applications in industry. Depending on the position in the furnace and specific process requirements, refractories are produced from several raw materials, such as dolomite, magnesite, bauxite, graphite or chromite. Most of these raw materials are not rare but strict quality requirements limit the producers of refractories to only a few deposits in the world. Thus, raw material supply is a critical factor for the production of refractories and accounts for 40-50 % of the total costs of refractories.A possible way to lower dependency on raw material supply is recycling of spent refractories. Main challenge in recycling is the separation of different brick types from each other and the removal of impurities, such as steel or slag. The European FP7 project REFRASORT aims to apply sensor-based sorting for separation of spent refractories. Sensor-based sorting is known from food industry, recycling and mineral processing and has proven its reliability. Nevertheless, some adjustments are necessary compared to applications in mineral processing because of other sensor-types and a higher number of products in one sorting step. This paper presents the results of feasibility tests for sensor-based sorting of refractories with near infrared spectroscopy and laser-induced breakdown spectroscopy (LIBS). Both sensors showed the potential to identify different brick types but the most promising results were obtained using LIBS technology. INTRODUCTIONRefractories are solid, ceramic products, which can sustain temperatures of more than 1500°C, without losing their stability or shape. Bricks of refractories have to withstand corrosion in contact with liquid steel or slag. Various high temperature applications, such as the production of glass, steel, copper or cement, require high quality refractories. The quality requirements of refractory bricks are strict, because small impurities can lower the thermal strength significantly."

Jan 1, 2016

By Howard M. Wells

Portfolio theory and the Capital Asset Pricing Model (Modigliani and Pogue, 1974) provides an investment decision rationale which takes account of the benefits of diversification in reducing effective risk, but this theory does not consider the financial capability of the firm to survive large losses if they should occur. The LL-curve theory (Wells, 1976) takes the latter consideration into account, but it does not provide for the effects of diversification. This paper pro- poses a general theory to account for both diversification and the financial capacity of the firm to underwrite the investment risks.

Jan 1, 1983

By James S. Baker

LARGER than continental United States but with only about one third the population, Brazil is a land of enormous potential wealth, waiting to be developed. During a recent visit to that country I saw Brazil at war and learned about some of the recent mineral developments. Many engineers and geologists have been sent to Brazil by various U. S. Government agencies to assist the Brazilian producers and co-operate with the Brazilian Government in producing needed war minerals. The Foreign Economic Administration staff of engineers has been active and through their assistance to the Brazilian producers, steadily increasing quantities of strategic minerals were provided to aid the United Nations' war effort. Mineral wealth has been found in almost every state of Brazil. Many mineral deposits have been discovered during the war period. Examples are: barite near Bahia; the tungsten and molybdenum deposits in Rio Grande do Norte; and corundum, beryl, and tungsten ores in Ceara.

Jan 1, 1945

By N. W. Xu, M. D. Wei, F. Dai, B. Li

"Chevron notched samples achieve general acceptance for measuring the Mode-I (opening mode) fracture toughness of rocks. The cracked chevron notched semi-circular bending (CCNSCB) sample, which is developed from the International Society of Rock Mechanics suggested the cracked chevron notched Brazilian disc method, has recently received much attention. However, these chevron notched methods have not been fully mastered, some ideal assumptions based by their theories and formulas, such as the straight-through crack assumption (STCA), have not been verified detailedly. Fractures of CCNSCB specimens were numerically simulated considering different heterogeneities, geometrical and mechanical parameters. The results show that, the real fractures of CCNSCB specimens are never satisfied with the STCA. In fact, micro fractures not only occur in the notch tip but also the two chevron edges. Consequently, the crack front features prominently in a shape of parabolic curve, far from being straightthrough. Moreover, curvature of the crack front is only affected by shape of the chevron ligament. Cracks usually start from two sides of the notch tips rather than center of the notch width, and propagate deviating from the postulated fracture routes. These fracture mechanisms induce errors with the measurements, and thus more attentions should be paid to the real fractures of the chevron notched samples for measuring fracture toughness more accurately. INTRODUCTIONWith the increasing requirement of people for resources and energies, frequent rock engineering activities have been conducting, such as underground excavation, oil exploration and deep burial of nuclear waste. Many problems appear in rock fracture. Consequently, there are more and more attentions paid in rock fracture mechanics due to its broad application prospects for solving these engineering problems. Since Mode-I (opening mode) fracture is the most common failure mode in rocks, Mode-I fracture toughness is a primary parameter to predict rock mechanical properties in actual engineering, and thus its accurate values are necessary to the researches of rockburst, rock mass slope stability, rock cutting, hydraulic fracturing, tunneling, et al. Therefore, it is thus significant to evaluate and study relevant methods to obtain the reliable value."

Jan 1, 2015

By James Spiers

This paper describing the mining practice at the Central-Eureka mine is one of a series of similar papers being prepared by the United Staten Bureau of Mines on mining practices, methods, and costs in the various mining districts of the United States. The mining practices described in this paper are illustrative of the methods employed in the exploitation of comparatively low-grade gold ores under the extremely heavy and swelling ground conditions which occur in the Mother Lode belt of California. The Central-Eureka Mining Co. comprises a group of adjoining mines in Amador County near Sutter Creek. The principal mines of the consolidated group are the Central-Eureka, formerly known as the Summit mine, and the Old Eureka mine, which is also known as the Hayward Quartz mine. The group is situated in the most productive part of tae main Mother Lode belt, the 10-mile portion which lies between the towns of Plymouth and Jackson. The three largest producing mines of the entire belt at the present time are the Argonaut, Kennedy, and the Central-Eureka; these lie within a radius of less than 1-1/2 miles.

Jan 1, 1931

By M. Rylatt, E. Legault-Seguin, C. Mohns

"With energy costs increasing and ore grades diminishing, the role of preconcentration in hard-rock mining operations has gained greater interest. Dense medium separation is a process that can be conducted at particle sizes from 250 to 0.50 mm with high separation efficiency, depending on liberation characteristics of the valuable minerals. Pilot-plant case studies conducted at the SGS Lakefield site are presented, including mineral systems such as spodumene, sulfide-bearing gold ores, and complex sulfide ores. These case studies demonstrate that, for amenable ores, mass rejection of 20–60% is possible while maintaining recoveries of greater than 90%.RÉSUMÉ Au vu de la hausse des coûts liés à l’énergie et du déclin de la teneur des minerais, le rôle de la préconcentration dans les exploitations minières en roche dure présente un intérêt croissant. La séparation (ou concentration) en milieu dense est un processus pouvant être mené sur des calibres de grains de 250 à 0.50 mm avec un rendement élevé de séparation, en fonction des caractéristiques de libération des constituants des minéraux métallifères. Sont présentées dans cet article des études de cas menées dans des usines pilotes du site de Lakefield de SGS, lesquelles incluent des systèmes de minéraux tels que le spodumène, les minerais aurifères sulfurés et les minerais sulfurés complexes. Ces études de cas montrent que pour les minerais présentant les caractéristiques de libération appropriées, il est possible d’atteindre un rejet en masse de 20 à 60 %, tout en maintenant des récupérations supérieures à 90 %.INTRODUCTIONPreconcentration is the process of rejecting gangue minerals while ensuring recovery of valuable minerals prior to more intensive, downstream processing. Preconcentration has been practiced in the industry for many years, and is gaining greater interest as the industry copes with processing lower grade, more difficult ores, which typically require finer grind sizes and incur higher energy costs.The benefits of preconcentration are:• lower mining costs, which allows for nonselective mining;• lower process capital and operating costs (e.g., resulting from reduced grinding, flotation, and fines disposal stages);• increased ore reserves, which provides the potential to treat lower grade ore;• increased mine production without expansion of the existing plant or concentrator;• reduced overall tailings impoundment by converting the reject into a byproduct (e.g., underground backfill or aggregate);• improved efficiency of downstream processes (e.g., silica removal in electric arc furnace feed, removal of softer sliming minerals prior to grinding);• potential application to brownfield operations and greenfield projects; and• a “green” process option, which reduces processing energy consumption;– reduces mill feed;– increases stage metal recovery (higher grade feed);– increases mill metal output per tonne processed;– reduces surface plant, tailings dump, and tailings pond requirements because the plant has a small footprint and can be installed underground; and– can be applied to retreatment of old tailings dumps to recover metal values and reduce environmental impacts (e.g., dissolved metal runoff, acid drainage)."

Jan 1, 2017