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By R. J. Sheets

In 2009 the Gold Quarry open pit mine, located 11 km northwest of Carlin, Nevada, USA, experienced multiple large-scale slope instabilities of the upper east highwall that reduced gold ore extraction for nearly 18 months. The slope instabilities occurred within a weak, consolidated sedimentary sequence that exhibits strength characteristics that are transitional between soil and rock. Instability initiated as mining exposed the lower clay-rich sub-units of the Carlin Formation (Fm.). This deformation created preferential flow paths that allowed groundwater from the upper sandy sub-units to infiltrate low permeability clay-rich sub-units, thereby enhancing deformation of the slope toe which in turn destabilized the upper portion of the highwall. The outcome was a 160 m high slope instability that had a lateral run-out of 850 m. The effort to return the pit to ore production required both the geotechnical and hydrogeological investigations and the preliminary remediation mining activity to be concurrent. This approach required the development of detailed safety procedures and a requirement to modify the remediation design as new results were obtained. An initial challenge was to mitigate a near vertical, 90 m headscarp with blast induced, localized slope failures. Back-analyses applying numerical modeling indicated that the failure surface did not coincide with initial interpretations based on field observations; drilling results eventually confirmed this alternative failure geometry. The final remediation design incorporated shallower slope geometries and an approximately 3 Mt buttress along the base of the Carlin Formation and bedrock contact to reinforce the lower clay-rich sub-units. The outcome is a stable highwall within the Carlin Fm. following nearly ten years of repeated slope instability, and an example of the necessity to conduct appropriate geotechnical and hydrogeological studies during the early stages of a new layback evaluation or new open pit development.

Feb 23, 2014

By Girolamo Belardi, Silvia Serranti, Giuseppe Bonifazi, Roberta Palmieri

Ore textural and structural characterizations play a fundamental role in any preliminary study (i.e. comminution, classification, separation) addressed to the design and set up of beneficiation flow sheets. The possibility to utilise automatic tools able to perform a classification, and a quantitative description, of the mineralogical and petrographical characteristics of raw ore samples thus represents an important step to define, to control and to verify the entire set of parameters, ore-texture-related, that can affect the final beneficiation results. The procedure usually adopted is based on the analysis of polished sections and more in details the recognition of the different mineralogical species and associations and the measurements of some quantitative parameters estimating both the geometrical characteristics of each species and the possible spatial relationships between them. This approach, originally carried out by experts, utilising optical and/or electronic microscopy, was ‚replaced? during the years by more and more sophisticated devices integrating analytical facilities and acquired data processing. Such integrated analytical devices formed the breakthrough platforms into what is now known as modern Process Mineralogy. In this paper the possibilities offered by chemical imaging based devices and techniques, to perform ore minerals recognition/classification, and to perform their topological assessment, are presented. Tests have been carried out and are discussed in order to analyze the problems related to the development of suitable and low cost strategies addressed: i) to realize a full mapping of ore minerals/gangue inside selected samples, ii) to define the optimal data-flow handling to optimize the speed of processing versus the quality of the results and iii) to start to define logics and procedures finalized to implement innovative smart detection engines, chemical imaging based, for mineral processing addressed to perform both a preliminary characterization of the ore, at laboratory scale, and a further possible control of the different processed minerals flow streams.

Jan 1, 2014

This report presents the results of a study of mill tailings disposal practices and potential tailings dam stability problems. Recognizing the long period of time that would be required to develop the technology and practices necessary to significantly improve refuse disposal safety, the Bureau initiated this research effort as a first step in that development. Volume 1 includes a summary of conclusions and recommendations resulting from the overall research effort; discussions of disposal systems and methods, geology, seismicity, hydrology, and materials characteristics; evaluations of investigational techniques; discussions of usable interim generalized investigational, analytical and inspection procedures; discussion of general principles and presentation of a tailings technology manual outline; and discussion of needed future research am recommended programs.

Jan 1, 1974

By Michael Jatczak

The San Vicente Tunnel Project is an 11-mile water tunnel constructed for the San Diego County Water Authority. One of the many challenges of the project included tunneling a 22,000-foot single-heading tunnel on the western half of the job in varying geology using a 3.66m (12ft) diameter open shield excavator or ?digger shield.? This paper will discuss the design considerations for the temporary liner, the tunneling, and ancillary equipment. It will also highlight the challenges faced while mining this geology, explain the methods implemented to drive this section of tunnel, and discuss the experiences while performing mechanized tunneling in an extensive and varied San Diego geology.

By A Buckley

Many policy issues facing the mining industry and affected communities are at a level of complexity that they can be called ‘wicked’ problems. The term ‘wicked’ in this context is used, not in the sense of iniquity, but rather as social and economic issues highly resistant to resolution. For the resource extraction sector and affected communities there are an array of challenges embedded in the industry’s production and profit paradigm, the remoteness of mineral reserves and affected communities’ expectations of economic benefit and a positive legacy. The mining industry as a whole is dominated by economic, political, legislative and market structures that influence and constrain interactions between mine operations and local communities. For communities, with particular reference to regional Western Australia, intractable problems include the uncertainty of, yet increasing dependence on, a mining economy. Questionable outcomes for local communities include the limited realisation of local employment and business development benefits, and low overall outcomes or low multiplier effects. ‘Wicked’ problems, according to the literature, are best addressed via collaboration. In the mid-west region of WA, with mining and infrastructure construction underway, alliances have formed between mining companies, the major port and rail infrastructure project (Oakajee Port and Rail) and regional and local governance stakeholders. The major impetus for these affiliations is to expedite planning and associated infrastructure development taking into account the lessons from other mineral-led regions. What has resulted is an array of innovative approaches to stubborn problems including planning well in advance of full-scale mining; regionally coordinated procurement; ‘mine ready’ local businesses; and strategic investments in social infrastructure; including community trust funds paid in advance of project delivery. This paper examines these innovative approaches/alliances and assesses their effectiveness in addressing long standing mining/community dilemmas.

Nov 22, 2011

The United States has not begun commercial operations to tap its largest poten-tial sources of oil supply - oil shale and coal. The reason is that domestic petrol-eum has been plentiful in the past and liquid products probably could be produced from it at the lowest cost. In view of the ever-increasing need for petroleum in the United States, the critical international situation threatening foreign supplies, the growing demands for steel, and the heavy costs to industry of constantly discovering and developing new oil fields, it is believed that the prompt development of a synthetic fuel industry based on oil shale and coal is not only requisite to safeguard our oil supply but is an economically sound course for the foreseeable future, To neglect its development is to close our eyes and minds to our own resources at a time when they are needed critically. It also is apparent now that neither the Government nor industry would be taking any considerable economic risk in starting the initial plants, especially as measured against their potential value in meeting critical oil and chemical demands and in building a new industry in the West.

Jan 1, 1951

By R. W. Raymond

The immense commercial value of the Gayley dry-blast process has been established beyond controversy. The testimony of practical blast-furnace managers, on both sides of the Atlantic, agrees that it reduces the cost of pig-iron about $1 per ton; but from the same testimony it appears that this direct economy does not by any means cover its commercial advantages—in fact, that under conditions frequently encountered in practice, it presents other benefits of even greater immediate financial importance. To this point I shall recur in a later part of the present paper. The history of the reception given to this invention, especially on the other side of the Atlantic, has repeated an experience familiar to American engineers. First, the reports of our practice were rejected as theoretically impossible, according to generally accepted notions and formulas; then the figures were reluctantly accepted; and finally the attempt has been made to explain how they could have been obtained. As to the Gayley dry blast, me Americans have been for several years in the last stage of the discussion, and the rest of the professional world is rapidly coming to it. Meanwhile, the remark has been repeatedly made that, whatever Mr. Gayley's process may turn out to be worth, it was not an invention on his part, but simply the energetic and persevering execution of a procedure already proposed by others. This question I wish to discuss first in the present paper. I. What Did Mr. Gayley Invent? Realizing that this is not the place for detailed argument on an issue of patent law, I shall not undertake to quote and criticise the publications prior to Mr. Gayley'a first patents. It may be admitted, without such critical analysis, that the possible advantages of removing moisture from the air forced into an iron blast-furnace were recognized and talked about a hun-

Jan 1, 1909

By D. W. Zandee

"IntroductionHaving mined an economic mineral bearing rock which is of insufficient grade to warrant direct smelting, upgrading or beneficiation is required to make it an economically viable ore. The first step in effecting the concentration process is comminution or sequential breaking of the rock to allow liberation and subsequent recovery of the desired mineral particles. Desirably the ore could be broken down to the point where the valuable mineral is completely liberated to maximize the chance of recovering as much of it and in as pure a form as possible. The number of energy intensive stages of breakage required to attain this goal depends on many physical characteristics of the ore such as hardness, friability, toughness, grain size, existing fracture planes and particle shapes.Commonly the distinct stages are primary, secondary and often tertiary crushing and finally grinding. To increase the efficiency of each stage of size reduction, pre-treatment sizing is common.Crusher feed is commonly scalped of large pieces or screened for reduction crushers and classified for secondary grindingcircuits.Although crushing and screening is employed for many different products, this chapter reviews current practice in larger tonnage metalliferous ore treatment plants.Current practice is to use large gyratory or jaw crushers for primary crushing and some sort of gyrating or cone crushers for additional stages of reduction. For autogenous or semiautogenous grinding circuits only the primary crushing stage is necessary, the balance of the work being performed in the grinding stage. For conventional grinding circuits using ball mills or combinations of rod and ball mills, secondary, tertiary and even quaternary crushing stages are normally required.Older type crushers such as stamp mills, double rolls, sledging mills and hammermills are no longer common but are used for small tonnage special processes.Important to efficient crushing are a variety of sizing devices such as grizzlies and vibrating screens. Products at different stages must be stored to give surge capacity and allow controlled feeding rates through mechanical and gravity feeders. These storage piles, bins and feeders as well as crushers and screens are commonly integrated into a total facility by means of conveyor systems. Most often these are endless rubber belts driven by simple or multiple drive mechanisms usually consisting of electric motors and speed reducers."

Jan 1, 1989

By Robert J. Evans

The Bureau of Mines is sponsoring a variety of long-term, high-risk research to advance state-of-the-art technology in U.S. underground coal mining. This report reviews the status of many Bureau projects that support fundamental underground coal mining operations; the project areas include cutting coal from the solid (extraction), hauling coal from the face (transport), and activities that sustain daily operations (logistics). Innovative equipment and technology have been developed, with these major objectives: to significantly improve coal mine productivity, to further advance coal recovery and personal safety within the mining industry, and to reduce the time needed to develop longwall panels. The majority of the prototype equipment covered in this report either has undergone or will undergo comprehensive evaluation at Bureau surface test facilities so that performance and reliability can be improved before the equipment is tested and evaluated in a working section underground.

Jan 1, 1988

By D. Farnell

Large semi-autogenous (SAG) or autogenous grinding mills have become the work-horse of the modern high volume concentrator. They typify the economy of scale - fewer, larger machines doing more work, more economically. With fewer machines, equipment reliability becomes of paramount importance. Realizing this, companies installing new or modernizing existing facilities have placed extraordinary emphasis on purchasing a reliable mill. This, in turn, has had a significant impact on mill design. Kennecott And Codelco - Two Different Approaches Last year, two of the world's largest copper producers, Codelco and Kennecott, undertook the modernization of their main grinding facilities at Chuquicamata and the Utah Copper Division (UCD) respectively. Both selected semi-autogenous milling and both, recognized the importance of the reliability of the primary mills. Each, however, decided on a different approach to optimizing reliability. Codelco placed the emphasis on technical innovation in design and opted for a gearless driven mill. Kennecott chose the more conservative approach of active participation and exceptional quality assurance in mill design and manufacture.

Jan 1, 1987

By M. P. Bohrer

A closed-loop hydrometallurgical process has been developed for treatment of smelter flue dust generated by copper recycling. The process is a semi-continuous operation in which zinc, iron, and copper are first extracted from the dust with a sulfuric acid solution. The lead and precious metals, initially present in the dust, remain as solids and can be recycled to the copper smelting furnace. Cementation with iron and zinc metal purifies the zinc and iron-rich liquid stream prior to spray drying. The spray-dried product, consisting of a mixture of zinc sulfate monohydrate and iron sulfate monohydrate, is a desirable micronutrient additive for use in animal feeds. Treatment of the smelter flue dust in this manner will generate a positive return on investment, as well as mitigate a potential environmental liability.

Jan 1, 1992

By Paul M. Tyler

"In preparing this paper the writer has perforce depended mainly upon published information, including the catalogs and pamphlets issued by importers and dealers such as the Diamond Drill Carbon Co. and J. K. Smit & Zonen. Special acknowledgment is made to various articles published by S. H. Ball. The writer of this paper, however, is alone responsible for statements herein contained and since he has often found it necessary to rationalize apparently conflicting opinions of recognized authorities on this little-known subject, he will welcome constructive criticism from the trade.Two types of diamond are extensively used for industrial purposes. One type, known as bort or bortz (boort, boart, bowr, etc.), consists of diamonds of the gem variety but unfit for cutting into gems. They may be colorless, yellow, brown, or gray. The other type, carbonado, known in the trade as ""carbon"" or ""black diamond,"" differs greatly from the white diamond, being opaque and apparently amorphous or noncrystalline. Actually, instead of forming a large single crystal as in a gem stone, carbon diamond comprises a mass of microscopic crystals that interlock to form a tough, homogeneous material with no planes of cleavage. It is found in various colors -- black, dark green, brown, and gray -- but usually it has .a dark lustrous black surface, with a resinoid or submetallic appearance, often resembling fine-grained steel. Upon exposure to the air the broken surface gradually darkens to an ash-gray color. Ballas is a special type of carbonado in which the crystals are definitely-oriented around a central nucleus. They are harder and tougher than ordinary carbonado but are much scarcer. The Cape ballas is reputed to be not quite so tough as Brazilian ballas but tougher than carbon or bort.The diamond crystals are isometric and take a variety of forms. The cleavage is octahedral and well marked. A crack is easily -started parallel to an octahedral face, and bort or gem diamonds are notoriously brittle, especially when subjected to sudden shock. Even carbonado, while it has a high resistance to slowly applied pressures, may be chipped or broken by a sharp blow.Exposed to radioactive rays, the diamond becomes phosphorescent; this property is often utilized to distinguish it from quartz, topaz, or glass. The unusually high refractive index likewise aids in its identification in the case of a more or less transparent stone. At the temperature of the electric arc, diamond is converted into graphite, another form of Carbon but one of the softest mineral substances. At a much lower temperature, as low as 1,5620 F., the diamond may be burned like ordinary carbon in an atmosphere of oxygen, and according to some authorities there is danger of burning a diamond if overheated even in air."

Mar 1, 1932

By S. Leong

This paper reports on research examining disclosures from mining companies regarding their water usage in the Macquarie and Lachlan catchment areas, both parts of the Murray-Darling Basin in New South Wales, Australia. The objective of the research was to assess whether this disclosure is sufficient to allow communities to determine whether mining companies are complying with mining conditions of consent and abiding by the requirements of their water licencing agreements. These requirements are then compared to the water reporting requirements of the Global Reporting Initiative (GRI) and the Water Accounting Framework for the Minerals Industry (WAFMI). Communities are concerned about whether the mining industry?s use of water will have impacts on their livelihoods and lifestyle and thus require information concerning the quantity of water that will be extracted, how much water will be left for other stakeholders and whether the mining will affect water quality. This is an archival study. It has involved examining relevant publically available information released by mining companies and government regulators and determining if this is sufficient to meet the needs of the local communities. Additionally, it has involved looking at information indirectly provided by mining companies, via the use of intermediaries. Further, information availability concerning basic water accounting and regulatory breeches and whether such information is available at the mine site level has been considered. It is found that while NSW legislation places very little reporting requirements on mining companies, the development consent conditions for new projects and extensions to existing projects are quite significant and should be sufficient to meet the needs of local catchment residents though such information is not always easily accessible for the layperson.

Aug 1, 2013

By Amoussou Coffi Adoko, Shevaune Zeng, Sebastian D’Hyon, Gareth Kennedy, Eleonora Widzyk-Capehart

Inertization of coal dust with stone dust is a common control implemented within underground coal mines to mitigate the hazard of a coal dust explosion. To achieve adequate inertization, the total incombustible content (TIC) of the coal/stone dust mixture is required to meet certain percentages depending on the risk and relevant legislation. Current methods for determining the TIC of a mixture involves laboratory analysis, colorimetric comparison, or the use of portable instruments. This paper provides preliminary analysis of determination of a sample’s TIC in real-time with chemometric modelling, using portable instruments employing near-infrared (NIR).

Feb 1, 2024

By J. J. Forbes

Since 1910 the Bureau of Mines has given training in the care and use of oxygen breathing apparatus under conditions that may exist during mine fires and after mine explosions. In 1929 the Bureau supplemented this instruction by initiating a course in advanced mine rescue training to prepare mine officials and others to organize men for mine rescue and recovery operations. The course of instruction has been developed and expanded since its inception to keep abreast with new ideas, methods, and equipment. Four miners' circulars were issued to be used in the training course. The first of this series (Miners' Circular 33) deals with mine gases and the various methods of detecting them; the second (Miners' Circular 34) gives instructions for sampling and analyzing mine atmospheres; the third (this circular) describes methods and equipment for protection against mine gases; and the fourth (Miners' Circular 36) explains procedures in sealing and unsealing mine fires and in conducting recovery operations, These circulars have been revised from time to time to keep them up to date.

Jan 1, 1954

By R. W. Courtney

The objective of this study is to make a critical evaluation of the magnitude and extent of electrostatic hazards in typical U.S. mining operations and to assess the adequacy of techniques, materials, and equipment for detecting and minimizing these hazards. This was accomplished with an incident/accident survey, mine visits, literature search, and engineering analysis. It was concluded that it would be desirable to (1) utilize ground fault interrupters to minimize stray current from electrical utilities, (2) decrease the current and electrostatic sensitivity of electric detonators used in areas with a high incidence of lightning strikes or troublesome stray currents, (3) institute quality control and test standards for blasting material and protective devices, (4) establish an electrostatic monitoring program for loading ANFO in plastic lined holes, and (5) establish a risk criteria for operator exposure in mines.

Jan 1, 1982

By D M. Silva, J C. Alves

According to the literature, material transportation represents 50 per cent of the operating costs for an open pit mine. In this context, this paper proposes a multistage approach for dynamic truck dispatching in real open pit mine environments, implemented in the commercial package SmartMine®, marketed by Devex SA. The first stage of this approach defines the optimal number of trucks that maximises the tonnage production by means of a robust linear programming model, which considers the operational constraints of a real mining process. The second stage uses a dynamic dispatching heuristic joining computational simulation and multicriterion optimisation techniques for decision making for truck dispatching. Another relevant contribution of this work is the publication of realistic instances collected from a dispatching system managing an iron mine, containing information about the hauling and loading fleet, the equipment situation when the working shift starts, cycle times, the time line of special occurrences (such as equipment stoppages and loading equipment reallocation in order to satisfy the mine planning) and the tonnage produced. These instances were generated with the purpose of submitting the method to the test of a real situation that considers the uncertainties existing in the process studied. The proposed approach was validated by means of a discrete event simulation model applied to the previously designated instances. Using this multistage approach as a mechanism for dispatch decision making, it is shown that the haulage fleet productivity increased when compared with the real values reported from the instances. These results are important because they show that the proposed approach generates efficient dispatch decisions for trucks operating in a real environment, reducing operating costs, increasing production and making the mine more competitive.

Sep 26, 2011

By M Jones, G Corder, A C. Keith

"Sustainable development has become an issue of ever increasing importance to the mining industry. The Ernst & Young (EY) mining industry risk radar regularly shows several sustainability elements in the top ten risks, with social license the number three risk in the 2014/15 survey. This is supported by the Fraser Institute survey results of 2013 showing that 36 per cent of responding companies indicated public opposition had affected their permitting and approvals process.Addressing these issues in a strategic way across a mining business that is then translatable to actions at operational level has remained an elusive goal in the industry. In addition the environment and community issues are commonly viewed as somewhat separate from financial and production issues and as a compliance cost rather than a value add. In their Harvard Business Review paper of 2011, ‘Creating Shared Value’, Porter and Kramer outline changes in thinking required for companies to improve their business sustainably through considering the societal issues impacted by their operations and products. Along the lines of ‘doing more with less’ companies’ value chains can be redefined to reduce energy, transport, water or other resource usage leaving additional resource for societal usage and/or reducing environmental impacts. This paper explores the linking of the holistic Five Capitals-based approach with the creating shared value (CSV) concept to help businesses unleash the benefits of innovation. Previous papers have demonstrated the potential for Five Capitals approach to create strategic value through sustainable development. Building on previous work, this paper provides an overview of the current status of holistic approaches to mine management and presents the application of the CSV concept on an African mine currently undertaking capitals-based strategic planning. The paper also demonstrates the value that has been created through utilising this approach and proposes improvements for changing the way the industry tackles and delivers benefits related to sustainability issues.CITATION:Keith, A C, Corder, G and Jones, M, 2016. Strategic sustainable development – creating shared value in the mining industry, in Proceedings International Mine Management Conference, pp 249-264 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Jun 22, 2016

By S. Pastor, S. Hahn

"As the concept of autonomous haulage systems (AHS) moves from prototypes to production-ready applications, the operating performance of the haul road will become critical to the overall success of autonomy in mining. Deterioration in road performance will require remediation, human intervention and significant, albeit temporary, changes to operating procedures, to accommodate road maintenance. With autonomous trucks comes the opportunity to reduce road formation and operating width. This will, therefore, generate potentially significant reductions in stripping ratios and improvements to mine economics, but only if the design of the road, and its associated deterioration rate, is predictable and manageable, based on the materials used to construct the road and the maintenance interventions to be carried out on the road.This article presents the assessment of a digital photogrammetric approach to the characterization of a mine haul road surfacing, or wearing course material. Design and maintenance parameters for these roads are currently determined partly from physical particle size distribution (PSD) assessments of ‘in-road’ material. However, this approach does not accommodate the need, nor leverage the benefits from, AHS. The digital imaging approach is assessed in this article, using two standard digital analysis software tools, together with in-service mine haul road wearing course samples and images that are analyzed to determine the applicability and reliability of the approach to deliver a real-time assessment of haul road surfacing conditions and thus to identify the road maintenance interventions required to address deterioration.Enhancements in mine road design, construction and management for the past 20 or more years has largely been focused on short-term tactical needs. These improvements have not been matched by advances in the fundamental technologies that underpin mine road design and management and, although the quality of mine roads have probably"

Jan 1, 2015

By J. H. East

THE RIFLE, COLO., oil-shale project of the Bureau of Mines was a facet of the re-search and development activities conducted under the Synthetic Liquid Fuels Act (Public Law 78-290) of April 5, 1944. The principal objectives were to devise efficient methods to mine and retort oil shale and to refine shale oil into usable products, at a total cost low enough that shale oil could supplement the domestic supply of petroleum at competitive prices. The Rifle project included three major divisions: (1) Mining, (2) retorting, and (3) refining. The major functions of the mining program were to supply oil shale to the retorts, to devise mining procedures, and to develop an under-ground-mining method by which oil shale could be produced safely at an unusually low cost per ton. The selected mining procedures and direct mining costs were demonstrated by sustained test runs.

Jan 1, 1964