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By Thorndycraftm R. B.

"PURPOSEThe purpose of this presentation to the Canadian Mineral Processors is to review gold heap leaching systems currently in use and discuss their applicability to Canadian ores. The author's experience with the development and operation of heap leaching spans the past four years at. Pinson, and visits to many ether heap leaches in the western United States.INTRODUCTIONBy way of introduction to the heap leaching system, I will describe in slight detail the method used at Pinson Mining in northern Nevada. This will be followed by a discussion of optional methods in use at other operations visited.The Pinson orebody is a finely disseminated, well-oxidized hydrothermal deposit. Gold particles are finer than 20- microns. The orezone hostrocks are metamorphosed and silici¬fied limestone and shale. Sulfides and carbonaceous materials are negligible.The Pinson open-pit mine has operated since June 1980. It produces 1500 tpd of C.I.P. mill feed averaging .10 oz gold per ton, and 1500 tpd of heap leach material averaging .025 oz gold per ton. Cutoff grades are 0.04 for mill feed, and 0.01 for heap leaching. Stripping ratio is 9 tons of waste and leach grade to 1 ton of mill feed.The project is located in northern Nevada at 4900 feet above sea level.,Winters are fairly severe, with freezing conditions affecting operations from early December through April. Although officially designated as ""high-mountain desert"" country, snow and/or freezing rain occur almost every week of the winter.To date, all Pinson production-scale heap leaching has treated run-90,000 tons of ore are stacked on 300 foot square clay leach pads. Cyanide leach solution is applied through ""wobbler"" sprinklers at .0025 gpm/sq ft for 60 to 90 days. The pregnant solution flows from the heap by gravity to plastic-lined ditches, into a collection sump and then through buried piping to the 2.2 million gallon pregnant solution pond."

Jan 1, 1984

By R Dimitrakopoulos, R Goodfellow

One of the primary objectives when optimising a mining complex is to maximise its value for the primary stakeholders. In order to achieve this objective, it is necessary to holistically optimise all aspects of the mining complex, including decisions of when to extract materials from the available sources, how to blend or stockpile these materials and how to best use the available processing streams to satisfy customer demand. Existing methods for global, or holistic, optimisation ignore the compounded effects that risk has on the performance of a mining complex. Over the past decade, several stochastic optimisation approaches have been proposed to integrate various forms of uncertainty into the open pit mine design and production scheduling. These methods, however, are limited in their ability to simultaneously optimise the production schedules for the portfolio of mines, material destination policies, the use of the available processing streams and the various products that are produced at each location of the mining complex.This paper aims to discuss a new method for the global optimisation of open pit mining complexes with geological uncertainty. The proposed generalised methodology is capable of modelling and holistically optimising mining complexes, including aspects related to production scheduling, blending, stockpiling and non-linear interactions that often occur in practice, but are over-simplified in existing models. Two case studies are discussed to highlight the need for these complex, stochastic optimisers. First, a case study for a nickel laterite blending operation highlights the need to integrate geological uncertainty into the optimisation in order to ensure product quality constraints are respected. Second, a case study for a copper-gold mining complex highlights the added value when simultaneously optimising the production schedule and the stockpiling and treatment of extracted materials.CITATION:Goodfellow, R and Dimitrakopoulos, R, 2014. Stochastic optimisation of mineral value chains – developments and applications for the global optimisation of mining complexes with uncertainty, in Proceedings Orebody Modelling and Strategic Mine Planning Symposium 2014 , pp 13–22 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Nov 24, 2014

By X. L. Huang

This paper deals with the experimental and theoretic study of the contact pressure beneath the deep foundation of Beijing International Hotel, The experiments have been carried out in project and in model footing 6.6m2. The result of measurements shows the contact pressure at the edge is greater than that at the center. The theoretic analysis on the base of elastic theorey is in good agreement with the test if the proposed assumption used.

Jan 1, 2010

By T. Tholana

South Africa hosts some of the world?s largest known resources and reserves of minerals that are strategically important to the global economy. The country?s mining industry contributes significantly to the national economy in terms of gross domestic product, export earnings, corporate tax receipts, remuneration earnings, and employment. Platinum, gold, and coal are significant minerals because they make the largest individual contributions to these economic indicators. Several factors impact the cash cost performance of operations that mine these minerals, thus affecting the future sustainability of these operations, which are generally ?price-takers?. It is therefore important that the cash cost performance of operations for these key minerals is analysed. Commercially available industry cost curves can be used for such analysis. However, some companies may not be able to afford to purchase these curves. This paper presents a simple Microsoft Excel® algorithm for constructing the curves. It also demonstrates how the constructed industry curves were used to analyse the cash cost performance of South African mining operations for the three selected minerals for the period 2007 to 2011, which included the 2008 global financial crisis. The analysis revealed that the operations were affected by several global and local factors during the review period. The work reported in this paper is part of an MSc research study at the University of the Witwatersrand. Keywords cost curve algorithm, economies of scale, cash cost performance

Jun 1, 2013

One of the most important goals of the experiments is to determine deformation and strength of the rock specimen under applying triaxial load, the status of failure condition is one of the subjects which can be used in soil mechanic and foundation engineering applications. To investigate the effect of confining pressure on the triaxial test, the rock has been considered as bonded-particles method and has been simulated by particle flow code three dimensions (PFC3D). This model, does not have pre-existing microcracks and all the particles have the same size (2 mm diameter), equal to the real specimen shape. To compare the mechanical behavior and failure pattern of the numerical and experimental results at uniaxial and triaxial tests at the same conditions, the Young's modulus, Possion's ratio as well as maximum axial stress have been considered. On the other hand, the microcracks growth and change of failure pattern at the modelling of the uniaxial and triaxial tests with different confining pressures up to failure point were reported. According to the experimental work, the number density of microcracks decreases from starting value and remains almost constant up to the failure beyond that point. The comparison of the numerical and experimental results of maximum axial stress and the Possion's ratio revealed good accordance. The initial number density of microcracks at the model was zero and increased while microcracking. Also, the sudden increment around the maximum stress was observed which is because of unstable growing of microcracks near the maximum stress. In all uniaxial and triaxial tests with different confining stresses, the number density of microcracks during the failure remains almost constant which can be considered as a proof of failure occurring in the model. The experimental results indicate the similar trend as well.

Nov 25, 2010

By T. T. Read

TWO papers on health and safety were given Thursday afternoon when a joint session of the Health and Safety Committee and the Mining Methods Committee was held. T. T. Read presided and the first paper, on ventilation at Climax, was presented by the author, L. H. Glanville. In the subsequent discussion by Cloyd M. Smith, P. B. Bucky, B. F. Tillson, D. F. Haley, J. L. G. Weysser, and others a number of interesting points not covered by the paper, which appears in full in the January Mining Technology, were brought out. Ventilation troubles in mines so often hinge on the air being too hot and damp that it was interesting to hear of one where it is frequently too cold and too dry.

Jan 1, 1943

By J B. Taylor

Geographic Information Systems (GIS) are being increasingly used by the mineral exploration industry in the search for new ore deposits. A mineral exploration GIS links geological and geophysical data by virtue of their geographic location in a digital map setting. Geological and geophysical data are categorised into a number of themes or layers within a mineral exploration GIS. These layers may include polygonal information such as rock type and tenements, line information such as faults and fold axes, point information such as mines and mineral occurences, and images such as gridded geochemistry and aeromagnetics. A mineral exploration GIS is a powerful tool to help the explorationist comprehend the spatial associations and interrelationships of his/her data. These spatial associations can be integrated with a mineral genesis model, to create a mineral prospectivity map to more effectively target exploration. Arguably a competent geologist who has a good understanding of the genesis of the local ore deposit types and knows their local geology backwards could intuitively derive a mineral prospectivity map. However, in an era of rapid data accumulation from many different disciplines, the ability to assimilate and understand is a huge task for any individual. A mineral exploration GIS enables the explorationist to spend more time analysing data and testing ideas, rather than finding and manipulating data into compatible formats.

Jan 1, 1994

By L. D. Ricketts

Discussion of the paper of L. D. RICKETTS, presented at the San Francisco meeting, September, 1915, and printed in Bulletin No. 100, April, 1915, pp. 711 to 737. FREDERICK LAIST, Anaconda, Mont.-I am going to tell you of some of the results we have been getting in Anaconda during the past two or three months in a large plant which was finished in May. We commenced work in Anaconda a year and a half ago on the construction of a leaching plant which was to have a capacity of 2,000 tons per day. The plant was to treat tailings from the concentrator, containing about 12 1b. of copper to the ton. During the past year we changed our plans and decided to use the flotation process on the tailings from the concentrator, which contained no oxidized copper, and apply the leaching process only to tailings which had accumulated in a large dump below the works. This dump contains about 15,000,000 tons of tailings, and since some of the copper in it is oxidized, we felt that the application of the flotation process would result in the loss of too much of the oxidized copper, particularly as time went on. In starting up we had a number of difficulties to overcome, as is usually the case. They were not of a serious character. The results obtained, so far, have been decidedly encouraging. During July the plant treated a total of 50,000 tons of tailings, or an average of 1,610 tons per clay. The extraction was about 83 per cent., which, on material of the grade treated, meant a. tailing assaying under 0.1 per cent. copper. The acid consumption was about 65 lb. per ton, and the fuel percentage in. roasting was about 4 ¼ . We expect to cut the fuel percentage in the next month or two to about 3 per cent., the high percentage during July being clue to starting up and shutting clown furnaces. We find that iron builds up in the solution to a marked degree. This is not a serious platter with us, because we have cheap sulphuric acid and can reject solution whenever it gets too foul. The extraction of silver has been remarkably good in the large plant. It has averaged better than 75 per cent. It seems that so long as we maintain salt in the solution to a percentage of 10 per cent., the extraction is good. We allowed the salt to fall off in order to find how low a percentage we could use. At about 7 per cent. the silver extraction fell to 65 per cent. This was to be expected, because silver chloride is soluble in strong brine, but not in weak brine.

Jan 12, 1915

Magnetic anomalies in the Southern Coalfields have been subdivided into two characteristic types. Each type is attributed to a separate cause, one being basement structure, and the other near-surface igneous intrusions.Detailed geological mapping of the area and the ability to sample throughout the coalmines greatly assisted in this subdivision.The Triassic sequence contributes no magnetic effect of its own except to diminish the effect of sources within the underlying formations by raising the level of observation.Detecting the presence of igneous intrusions ahead of colliery working faces by magnetic observations within the coal mines may be of value in preventing accidents caused by gas outbursts and in planning the workings so as to avoid loss of production time.

Jan 1, 1967

By Robin J. Batterham

We still need to innovate, but it is getting harder. The real price of metals is declining, return on shareholder value is lower than other industries, and there is a shorter-term focus on staying viable in a capital-intensive industry where timeframes for implementation of new technologies can be long (+I5 years). In this environment, the levels of R&D spent by major minerals companies are remaining steady at around 0.2%-0.5% of revenue. This is not large and to remain viable in the future, we need to be smarter about the way in which we do R&D. The mining industry is a knowledge-based industry. Driving down the cost curve demands innovation, which demands knowledge. To be smarter and more effective in our approach to innovation, a new paradigm is required Generating, capturing and using knowledge has evolved from Mode 1 (discipline based and clear distinction between basic and applied research) to Mode 2 (multidisciplinary, team-based approached with flow between basic and applied activities). Mode 2 is now seen to be much more efficient and to deliver better appropriability (Tegart 2003). To survive, we need to innovate, and the best way to do this is collaboratively. Some examples and pointers for the future will be given in this paper. THE CURRENT SITUATION The Rand report and other recent studies have painted a grim outlook for the mining industry. The real price of metals continues to decline (Figure 1) and profit margins remain thin. This is reflected in shareholder returnwhich are well below other industries (Figure 2)-and current management strategies-which reflect something of a "survival mode." The current focus for most mining companies is on short-term, incremental gains

Jan 1, 2004

As the theme of this conference is æRediscover OtagoÆ it would seem appropriate to revisit the era of the gold rushes and subsequent mining industry which rapidly advanced settlement and economic prosperity for Otago, and left permanent reminders in the form of historic mining sites, many of which are now encompassed within the Otago Goldfields Park. I have been invited to give a paper at this conference on the subject of æHistoric Goldfields of Central OtagoÆ. As well as having a working involvement with historic areas through my employment with the Department of Conservation, I have a personal interest in the early goldmining industry of Central Otago as my grandfather came out from Scotland in the 1890s to help construct gold dredges on the Molyneux. My grandfather made headlines in the local paper in 1920 when he believed he saw a New Zealand otter at Island Block near Beaumont - but that's another conservation trail that I will not pursue any further today! For this paper I intend to divide my time to cover the following topics. Firstly, I would like to sketch a mental picture of the characteristics that make up the Central Otago landscape, and the general perception that early miners must have had when viewing this foreign land. Then I would like to briefly discuss the changes and the consequences in the early gold rush to Central. Finally, I would like+ to discuss the establishment of the Otago Goldfields Park, which I will illustrate with several slides.

Jan 1, 1992

By O. Worku, J. H. Masliyah, Z. A. Zhou

ABSTRACT The viscosity of concentrated kaolinite or illite clay in aqueous suspensions was measured in the presence and absence of a small amount of montmorillonite (<1 wt%). To avoid solids settling and to increase the sensitivity of the suspension viscosity measurements, solids concentrations higher than 38 wt% were used. The pH of the suspensions and the concentration of calcium and bicarbonate ions were found to significantly impact the viscosity of the clay suspensions. The results showed a significant increase in the viscosity of kaolinite suspensions with the addition of as low as 0.25 wt% of montmorillonite on a solids weight basis. In addition to illustrating the role of water chemistry in modifying slurry rheological properties, our study demonstrated that viscosity measurement could be a simple, yet sensitive technique for determining the content of smectite clays, such as montmorillonite, in a complex mix of various types of clay.

Jan 1, 2012

By W. L. Batt

MODERN war means mechanization, and mechanization means raw materials, especially minerals-and lots of them. Let me recall a few events of recent history-events that constitute mile- stones down the road to the war now blazing on three continents and threatening to spread still farther. In 1932, Japan took Manchuria, largely upon the excuse that she needed raw materials; in 1935, Italy invaded Ethiopia, largely upon the excuse that Mussolini&apos;s growing nation needed raw materials-in this case oil; from 1933 to 1935, Germany cried out for a greater share of the world&apos;s natural wealth, and since 1938 has invaded or occupied ten other countries, frequently upon the excuse that she needed-and had a right to-more raw materials.

Jan 1, 1940

By Walter I. Paniagua

Drilled shafts and precast concrete piles were installed for the foundation of several structures in a reconfiguration project of a refinery in Minatitlan, Veracruz, in the Gulf of Mexico. The soils are alluvial deposits of flat land from the Coatzacoalcos River, which are embedded with layers of sand, soft clay, and peat. As part of a QC/QA program, load tests, both static and dynamic, axial and lateral, were performed. In this paper results of 32 axial tests are presented, in which typical load-displacement curves were measured at the top of the foundation elements; from the interpretation of these plots, data were recorded for ultimate side shear and in some cases for end bearing capacities, which are compared with the theoretical results of the final stage of the foundation design. The comparison shows that under allowable loads, side shear determines the bearing capacity of piles, even when the tip is embedded in a hard layer. Underestimation of the side shear is evident; therefore design criteria, as well as the methods used for obtaining soil parameters, should be reviewed.

Jan 1, 2007

By D. S. Bubar

This presentation will represent a diversion from the central theme of Cordilleran geology, in both time and space, as we move 2,000 miles east of Spokane to eastern Canada, specifically the province of Quebec, to discuss a major new Archean-age volcanogenic massive sulphide deposit called Louvicourt. The deposit is located in the Val d&apos;Or camp in the prolific Abitibi Greenstone Belt some 400 miles north of Montreal. It was discovered by Aur Resources in June, 1989 on a property operated under the terms of a joint venture with Louvem Mining, a Quebec company controlled by Ste. Genevieve Resources Inc. of Montreal. As a geologist, I am proud to be able to describe Louvicourt as a geological discovery, as it was found by doing systematic deep diamond drilling based on a geological concept. The deposit is essentially blind from surface and lay undiscovered for the 10 years that the Louvem mine was in production just 2,000 feet away from its easternmost workings.

Jan 1, 1991

By E. W. Davis

THE large iron-ore producers on the Mesabi Range are able to maintain the silica in their shipping products at from 8 to 10 per cent by mixing ores of various grades, some assaying 4 per cent silica and some as high as 18 per cent silica. For each ton of 4 per cent silica ore mined, a ton of 14 per cent silica ore can be mined and mixed with it and the average grade maintained at 9 per cent. This mixing operation has made possible the utilization of large cluantities of ore too lean to be used alone. and herein lies the advantage of the producers who operate a number of mines at the same time. As the grade of the ore from one of the properties falls off, a little high-grade ore from another property can be mixed with it and the average maintained, while if one property alone were being operated all of the ore below grade would be left behind.

Jan 1, 1930

By D. J. Parker

Owing to its flexibility, convenience, economy, ands availability, electric power is peculiarly adapted to the needs of the coal -mining industry. Because of such obvious advantages, the application of electricity has in recent years become more and more extensive and is now a most important factor in the Nation&apos;s coal prediction. With the introduction of this type of power into coal mines certain new, specific, and well-recognized hazards resulted. The question arises, therefore: Has the industry met these hazards squarely and. effectively? With respect to some individual companies, the answer happily is in the affirmative; with respect to the industry as a whole, there is much room for improvement.

Jan 1, 1933

By Hui-bin Wu, Rui Yuan, Yang Gu, Peng-cheng Zhang, Zheng-zhi Zhao

The corrosion behavior of three kinds of medium-Cr rolled steel pipeline steels in carbon dioxide collecting and transporting environment at different temperatures was studied. The results shew that the 5Cr sample was most affected by temperature. When the temperature rised from 30 °C to 90 °C, the corrosion rate increased from 0.12 mm/a to 1.87 mm/a, which was increased 15.6 times. The corrosion rate of 7Cr steel at 30 °C was similar to that of 5Cr steel. However, as the temperature increased, the corrosion rate rised slowly, increasing by 2.4 times at 90 °C. The corrosion rate of 9Cr steel was not obvious with temperature, and it was always below 0.06 mm/a. The thickness of the corrosion product film of the three samples gradually increased below 70 °C, and suddenly increased above 70 °C. This was related to the negative temperature coefficient of the solubility of FeCO3, and the thickening of the product film also affected the ion exchange of the cathodic reaction. An increase in the Cr content contributed to grain refinement and increased the proportion of the small-angle grain boundaries. More fine grains mean an increase in the total length of the grain boundaries, which could provide a diffusion channel for the free Cr element; on the other hand, the low-angle grain boundary structure was more orderly, with a lower free volume and lower interface energy. Under the combined effect of both, 9Cr steel and 7Cr steel had high volta potential and better corrosion

Oct 1, 2019

By A. E. Halim, J. F. Brune

Debate continues over whether barricading in refuge chambers is a good strategy to survive entrapment emergencies in underground coal mines, in particular fires and explosions. Unlike U.S. coal mines, Australian coal mines are not required to use refuge chambers and, instead, have adopted a strategy that focuses on instructing and training miners to self-escape to the surface. This paper analyzes the merits and problems of using refuge chambers or self-escape to the surface to manage emergencies in fires or explosions in an underground coal mine. We found that using refuge chambers may not be the best strategy during extensive fires or when multiple explosions occur. In these situations, mine rescuers are unlikely to be able to extract miners who are sheltered in chambers and, conversely, self-escape may save more lives than sheltering. Chances for successful self-escape are further improved by regular, externally assessed training such as the level 1 emergency exercises required in Queensland, Australia. These exercises put pressure on mine operators to ensure and maintain the effectiveness of their emergency management system.

By B. P. Watson, D. P. Roberts, R. A. Lamos

The Upper Group 2 (UG2) chromitite reef is a shallow-dipping stratiform tabular orebody in the South African Bushveld Complex, which strikes for hundreds of kilometres. Mining is extensive, with depths ranging from close-to-surface to 2 500 m. Pillars are widely used to support the open stopes and bords. Little work has been done in the past to determine the strength of pillars on the UG2 Reef and design was done using formulae developed for other hard-rock mines. This has led to oversized pillars with consequent sterilization of ore. In this paper we describe a back-analysis of stable and failed UG2 pillars on the Bushveld platinum mines, and provides a strength formula for UG2 pillars. The formula may be used cautiously on all Bushveld platinum mines with similar geotechnical, geometrical, and geomechanical conditions to the pillars in the database.

Aug 1, 2021