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By R. Amelunxen

"The molybdenite associated with copper porphyry ores is generally treated in a flotation circuit consisting of a separation and a cleaning section. In the last few years column flotation cells have replaced the numerous counter-current stages that were previously used in the cleaning section. Despite this, little has been published regarding the number of column cleaning stages required. Therefore a Moly flotation database is assembled with the objective of verifying the existence of a common upgrading profile. This can then be used as a guide in the prediction of the number of stages required to achieve a given concentrate grade.INTRODUCTIONAlthough the first use of Column Flotation was on copper flotation products, the popularity and understanding of their operation was not really achieved until they were widely implemented in Moly circuits in early 1983. The use of columns in Moly plants has since left a legacy of information, both published and unpublished. The data collected since that time has been used primarily used to establish column operating parameters and to determine upgrading potential within the circuit.Byproduct Moly generally occurs with porphyritic copper ores in concentrations less than 0.1% MoS2. As such, piloting a new moly ore to produce, say 5 Kg/Hr MoS2, in a slurry approximately 1 Lt/min (at 10% solids), requires a moly plant feed of about 570 Kg/Hr, which translates to a mill feed rate of 200 to 800 Tonnes per day (depending whether you deal with Chilean or Canadian ores). Piloting Moly for any lower tonnage would reduce the accuracy of the testwork.Thus a need exists to collect operating data in order to establish the existence of process relationships that could be used for feasibility and design purposes.The object of this paper is to expose a preliminary relationship that could be used for the purposes described above and to apply the findings to a preliminary design of a moly cleaning circuit flowsheet."

Jan 1, 1990

By Jay A. Berger

Nondestructive testing of deep foundations for integrity problems made great strides in the late 1980's. Inexpensive portable computers have allowed the immediate and rapid processing of field measured acceleration records which can provide insight into the relative structural integrity of a previously installed foundation member. Although the gathering, processing and displaying of the data is now straightforward, interpretation remains at times rather challenging. This paper provides a brief introduction into the theoretical basis for data interpretation and the hardware necessary for data acquisition. Five case studies are discussed which demonstrate the varied applications of low strain integrity testing of deep foundations and the efficiency at which they are completed. BACKGROUND One dimensional wave mechanics, when applied to a linear elastic pile with a length that is an order of magnitude greater than its width, provides a straightforward basis for the interpretation of motion measurements made at a pile top. When impacted, a stress wave travels through the pile at a wave speed, c, which is a function of the elastic modulus, E, and mass density p (i.e., E=pc2). The applied load F, and particle velocity v, at a point are related by the equation F=Zv. For a cross-sectional area A, the proportionality constant Z is equal to EA/c. Because Z is a measure of the pile's resistance to change in velocity it is called the pile impedance.

Jan 1, 1990

By Huang Qiming

The CISDI-GreenEAF innovatively applies the top-side-chute for charging for improving the cold zone of electric-arc furnace (EAF) requiring preheating scrap. It can greatly reduce the operating power consumption during EAF melting by combined use of fume for preheating scrap. The enclosed charging mode and specially-designed structure contribute to less emission of dust and fume during charging while enhancing the metal yield. Thanks to the extraordinary fume temperature control at scrap preheating procedure and fume quenching technology as developed by CISDI, for restraining the regeneration of dioxin.

Oct 30, 2017

By Philippe Angers

This article analyzes the social acceptability process of a mining project located in an existing city. It will explore how the principles of sustainable development have been integrated in the project of the Canadian Malartic open pit mine held by the Osisko Mining Corporation, and the corporate social responsibility (CSR) initiatives proposed to strengthen the social acceptability of the project. This mine is located on the ancient south quarter of Malartic and has required the displacement of hundred of houses and five institutions. The location and the inherent social impacts generated by the relocation of the citizens of the south quarter makes this case particularly interesting to understand social dynamics in an era of environmental consciousness. These major constraints of the mine generate high expectations within the urban population with regard to the social and economic benefits it will receive from the project. In a context where society demands higher CSR from the corporation, Osisko is closely followed regarding their actions toward the sustainable development principles to see if they respect the environment and the desires of the community. From the beginning, the company had to be a model of sustainable development in various aspects reflected by the manifold interest of the population. To understand the endeavor made by the company to fulfill the demand of CSR, we will analyze how the company understood sustainable development principles and what CSR initiatives Osisko company put forward. We will explore the involvement of the company in various social aspects like employment, employee satisfaction, and the level of commitment to non-discrimination policy in employment, notably with the native populations. We will also take a closer look at the relationship built by the company with the community and the level of commitment with the various stakeholders of the community. In this way, we will be able to seize the level of involvement of the company in the fulfillment of the principles of sustainable development toward a higher CSR, and to specify the trajectory adopted to build social acceptance.

Aug 1, 2013

By J. C. Edwards

A series of four coal combustion experiments (I)' was conducted at the National Institute for Occupational Safety and Health, Pittsburgh Research Laboratory in the Safety Research Coal Mine to evaluate the response of optical and ionization smoke and CO sensors to a small 0.61 m square smoldering coal fire which transitions to flaming combustion in the presence of diesel emissions. With the increased utilization of diesel engines in underground coal mines, it is important to be able to discriminate fire products-of-combustion (POC) from diesel emissions. One proposed method to accomplish this is the deployment and interpretation of multiple sensors.

Jan 1, 2010

By Wen Tao Liu, Tong Tian, Fu Sheng Niu, Xiu Man Liang

In order to address the difficulty of accurate segmentation of froth images of different sizes, a method of froth image segmentation based on highlight correction and parameter adaptation is proposed. First, a machine vision system on a single-cell flotation machine is built to collect froth images. Homomorphic filtering is used to improve the uneven brightness and shadow of the images. Fuzzy c-means (FCM) clustering is then utilized to classify similar highlights that belong to the same froth. After Otsu threshold segmentation, a parameter-adaptive morphological operation is used to extract the marker points and edge bands and correct the froth edges in the original image. Finally, the modified image is filtered by morphological reconstruction, and the highlight mark is used as the local minimum point for watershed segmentation. Three sizes of froth images are segmented in comparative experiments. The results show that the proposed method is suitable for the segmentation of froth images of different sizes. The position of the extracted segmentation line is close to reality, with average over-segmentation and under-segmentation rates for froth images of 2.6% and 6.8%, respectively. The froth image segmentation performance is stronger than that of the other methods examined.

By T D. H McGrath, W P. Staunton

Benchmarking, comparing an operation or process with the industry standard, is known to be a useful method for identifying plant optimisation opportunities, and in many cases providing the pathway to realise the benefits. The difficulty is generating the database of plant data necessary for a benchmarking exercise. Larger companies can benchmark internally; this option is not available to smaller companies, and the full value can only be realised with a comprehensive “industry wide” approach.The Gold Technology Group at Curtin University through the AMIRA P420 series of projects has undertaken several comprehensive metallurgical industry surveys in the gold industry over the last two decades. Analysis of these surveys has demonstrated areas where many operations can benefit from re-assessment of their operating practices.This paper will review the work undertaken by the Group in this area, in particular the 1999 surveys of gold companies in the Australasian region, and the 2012 international survey of the industry. The challenges of, and opportunities arising from these surveys will be discussed. Some of the highlights from analysis of these databases will be presented as well as noting changes in processing practices observed by the Group over the last 20 years.CITATION:McGrath, T D H and Staunton, W P, 2018. Keeping up with the Joneses – the value of industry surveys and benchmarking, in Proceedings 14th AusIMM Mill Operators' Conference 2018, pp 509–516 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 29, 2018

Samples weighing 0·5 g are decomposed with hydrofluoric and other acids. Most elements are extracted ftom the acid, aqueous solution by Alamine 336 (tricaprylyl tertiary amine) and thorium is determined in an aliquot taken from the aqueous phase by means of its reaction with arsenazo III. Concentrations down to 4 p.p,m. may be determined at a rate of 100 samples per man-day of 8 hr.

Jan 1, 1971

By David B. George

Kennecott Utah Copper adopted Outokumpu Flash Smelting and Kennecott-Outokumpu Flash Converting in 1995, a process based on granulating high grade copper matte. While nickel mattes and very small quantities of copper matte had been commercially granulated for years, no large scale copper matte granulation system had been built. This paper summarizes the history and benefits of copper matte granulation, the Kennecott design basis, the successful operation for over 10 years and potential problems inherent in some matte granulation approaches.

Jan 1, 2006

By G. R. Dunning, M. R. Wilson

"Abstract - The early Paleozoic accretionary tectonic regime that was established along the Laurentian margin of the Newfoundland Appalachians provided a favorable setting for shear-hosted gold mineralization along a major terrane suture, the Baie Verte-Brompton Line. The Stog’er Tight prospect is one of several mesothermal-style gold occurrences hosted by shear zones within accreted ophiolites and oceanic arc terranes on the Baie Verte Peninsula. It is an epigenetic, stratabound deposit that is confined to shallow-level gabbro sills within the volcanic cover sequence of the allochthonous Point Rousse ophiolite complex. Gold mineralization at Stog’er Tight is associated with hydrothermal mineral assemblages represented by chlorite-calcite, sericite-ankerite, red albitepyrite (±Au) and chlorite-magnetite alteration zones. Gold occurs with pyrite within the intensely altered gabbro, along the margins of syn- to late-shear, quartz-rich, replacement veins.The Stog’er Tight gabbro served as a rigid body conducive to shear deformation and fluid penetration, whereas, its high Fe-Ti oxide content induced fluid oxidation and gold-pyrite precipitation. Hydrothermal alteration involved progressive CO2, S, Na, and LILE metasomatism, along with significant enrichments in the REE, HFSE, and Th in the high-grade ore zone. Temperatures of vein formation and alteration are constrained by oxygen isotope thermometry to be between 250°C and 480°C. Isotopic compositions of vein quartz from the Stog’er Tight prospect are uniform (??O = +12.5 ± 1‰) and fall within the range cited for many shear-hosted, auriferous quartz veins.A U-Pb zircon igneous age of 483 +3/-2 Ma for the Stog’er Tight gabbro is consistent with its stratigraphic correlation with other Ordovician ophiolitic and volcanic arc/back-arc assemblages in Newfoundland. The U-Pb age of a rare variety of hydrothermal zircon recovered from the high-grade ore zone directly constrains the timing of gold mineralization to 420 ±5 Ma, in accord with a major orogenic episode of Silurian age that produced many of the magmatic and metamorphic rock suites in north-central Newfoundland. Our results are consistent with a post-peak metamorphic, late-magmatic model for gold mineralization that occurred during the waning stages of Silurian orogenesis, driven by emplacement of I-type granitoid intrusions into the crust."

Jan 1, 2000

THOSE who dabble in mining are no exception to the general rule that persons who know a little of a subject are apt to think that they know all about it. Some colour may be lent to the belief that anyone may succeed in mining when we hear stories ofsuccessful diggers and others who have accidentally dropped on to something good through no foresight on their part; but we seldom hear the contra account of the far larger number who fail. Those who go more thoroughly into the subject, and take up mining as a profession, know very well that it is not one that can be carried out successfully by rule of thumb, but when they point this out to the public they are credited with trying to make it a closed profession; and outsiders are for ever trying to find out the "trade secrets," at the same time spurning the main one, which is hard study, experience, and the ability to apply their knowledge. The average mining man is not rich. When he amasses a fortune it is generally through speculation rather than professional work, thought no doubt his technical knowledge may have assisted...

Jan 1, 1910

Sufficient time has elapsed since the enactment of the amendments to the mining legislation in 1981 to enable an examination to be made of the way in which the licensing system operates in practice. One of the most important decisions in resource management in New Zealand is whether or not rights of access to the resource should be conferred by the Crown upon an appropriate private sector participant. The licensing system is the means for allocating these rights of access. The manner in which the licensing system is administered, therefore, is crucial to natural resource management in New Zealand. What is the mining licensing system in New Zealand designed to achieve? This simple question admits of no easy answer. Is it the identification and development of the mineral resources of New Zealand? Are these objectives tempered by issues of resource conservation and environmental protection? Is a balance to be achieved among these competing factors? Does the legislation contain any priorities? Does the system respond in an ad hoc manner to particular facts and circumstances or does it operate within a more predictable framework? To what extent are decisions made on access to minerals with reference to the development or conservation of other resources? These questions may be summarised in the title to this paper which poses the question whether mining licences are instruments for resource management.

Jan 1, 1988

Peñasquito is Mexico's largest gold producer, consisting of two open pits - Peñasco and Chile Colorado - containing gold, silver, lead and zinc. Over the next three years, mining activities in the pit are expected to be focused on lower grade ore in the upper parts of the Peñasco pit while stripping is emphasized to ensure an economically optimal pit shell design to maximize the net asset value of the operation. By 2019, Peñasquito’s gold production is expected to benefit from an improvement in mined grades as it recommences mining higher grades at the bottom of the Peñasco pit and significantly enhanced metallurgical recoveries with the planned completion of the Pyrite Leach Project ("PLP").

Jan 1, 2017

By Robert A. Jankowski, J. Drew Potts

In this U.S. Bureau of Mines study, four underground respirable dust surveys were conducted to determine factors affecting belt entry dust levels and how using belt air to ventilate work areas affected dust exposures. Belt entry dust levels on the surveyed longwall and continuous miner sections averaged 0.59 and 0.26 mg/m3, respectively. The stageloader-crusher contributed an additional 0.5 to 0.9 mg/m3 of dust to belt air, while the feeder-breaker contributed 0 to 0.2 mg/m3 of dust. A 1,000-ft increase in belt entry length or a 200- to 500-st-per-shift increase in production resulted in roughly a 0.1-mg/m3 increase in dust. Using the belt entry as an intake entry on the continuous miner section appeared to reduce dust levels by 0.1 to 0.3 mg/m3 during cutting. Belt air was not used to ventilate the face on the longwall section.

Jan 1, 1992

By J. O?Shea

From the characteristics of the new (1976) electronic components and units that are being marketed, the author has tried to foresee the types and the performances of the near-future slope-monitoring equipment. Much-improved sensors, instruments and systems for pit use can now be developed - sun-powered telemetry remote stations are feasible, very sensitive as well as precise and drift-free liquid level inclinometers will be available, new techniques for distance measurement with lasers obviate the need for atmospheric corrections and the latest generation of desktop calculators have become easily programmed minicomputers. Thus, it is realistic to assume that fully automatic pit-slope monitoring systems will be operational in the foreseeable future.

Jan 1, 1978

Bio-Oxidation of Arsenic and Stibium Bearing Gold Ores Bio-oxidation of arsenic and stibium bearing gold ores with acidithiobacillus ferrooxidans was studied. The preoxidation results show that the best bio-oxidation technical parameters are the initial pH in the range of 1.8 ~ 2.0, particle sizes under 0.074 mm, temperature in the range of 25¦C ~ 30¦C and rotating speed of the orbital incubator in 100 rpm ~ 160 rpm. The leaching results show that If the ore, of which contain 10.37 per cent arsenic and 36.81 per cent stibium, is not bio-oxidised, gold leaching is only about 41 per cent, after 8 days oxidised, the result is about 76.55 per cent, which improved about 35.62 points. The relationship between gold leaching and arsenic oxidation is direct proportion, furthermore, it needs only partly oxidise and higher gold leaching could be get, for example, gold leaching is over 90 per cent when asenic oxidation is 60 per cent. The results will provide theoretical and technological supports of bio-oxidation arsenopyrite for pretreating refractory gold ores.

Sep 13, 2010

Since the ecrly 1970's several factcrs have changed. In the East the larger tracts of coal mined with large eauipment are being dePleted, The cost of moving the larger equipment from small tract to small tract becomes eccnomicallv unattractive, Conseauently, the tracts are being mined with smal!er draglines or with loader/truck haulage combination, This has resulted in a major increase in the cost of moving a cubic yard of overburden,

Jan 1, 1989

By Wesley G. Holtz

A project to demonstrate the feasibility of retorting oil shale by the Paraho vertical retort process was carried out at Anvil Points, Colorado during 1974 to 1976. As a part of the demonstration project, laboratory and field tests were performed to determine the physical and chemical properties of the retorted shale for use in the development of eventual full-scale disposal plans. The material which exits from the Paraho retort is classified as a non-plastic silty gravel by the Unified Soil Classification System. The particles have an apparent specific gravity averaging near 2.60 and a mass specific gravity averaging near 2.00. The material can be compacted by normal laboratory and field construction methods to about 90 to 100 pounds per cubic foot dry density depending upon the degree of compactive effort applied. The addition of moisture does not improve compactibility appreciably. When high compactive effort is applied the retorted shale is classed as impervious to water flow. The compacted retorted shale exhibits shear strengths in the same order as those observed for silty gravel soils. If the compacted material is cured (long tune simulation testing) prior to strength testing considerable strength gain can be obtained from cementing action. The amount of cementing developed is dependent upon heat treatment and other operating modes of the retort.

Jan 1, 1976

By Andreas Oberrauner

Content ? What is? an introduction ? Crushing technology ? Conveying in pits ? Pit-exiting strategies ? Mine Planning in IPCC ? Summary/Conclusions EHS slide ? Sandvik?s objective is zero harm to our people, the environment we work in, our customers and our suppliers ? Current EHS-figures will be added in August! Who is this? Andreas Oberrauner ? Born in Austria ? Living in Cologne (Ger) ? Mining Engineer ? Montanuniversitaet Leoben (Austria) 2000-2005 ? PhD on Mineral Processing 2008-2012 ? Sandvik Mine Planning Department ? Main task: Provide practical and efficient solutions for mining-challenges

Aug 1, 2013

Study on the Effects and Mechanics of Na2SO3 to Chalcopyrite and Galena

Sep 13, 2010