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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 The use of columns in Moly plants has since left a legacy of information, both published and unpublished.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 J. Gotor, C. Frias, E. Delgado

The Iberian Pyrite Belt (IPB) is one of the world's largest reserves of primary sulphides containing base metals (Cu, Zn, Pb), precious metals and some special metals such as indium. Estimated resources are over 1,500 million tonnes of volcanogenic massive sulphide ores. From 1980´s Europe lives the decline in its mines mainly motivated by the low price of the metals. One aspect that contributed equally to this was the ecological disaster produced by the discharge of more than seven million tonnes from the tailings dam of Boliden-Apirsa (Aznalcollar) in 1998. Today the situation is different; the companies present in the IPB have given evidence that it is possible to reconcile mining projects and care on the environment, and the regional authorities are opening a public tender to re-start Aznalcollar mine. A new challenging era has been started at this Spanish/Portuguese mining area. This paper presents the results and preliminary economics of a project devoted to IPB primary sulphides processing through different technology approach, e.g. conventional selective flotation against bulk flotation or mixed metals flotation combined with hydrometallurgical processing.

Jan 1, 2014

By J. -H. Wu, S. Nishiyama, Y. Ohnishi

The behaviors and stress distributions of the inclined jointed rock masses with different dip angles obtained from DDA are compared to the results of laboratory tests. By calculating the block stress distributions, it is confirmed that DDA can reproduce the arching around the trap door when lowering the trap door. The shapes of arching change with the angles of inclined layers. In addition, the earth pressures acting on the trap door shows non-symmetrical distributions when the layers are not horizontal. The stress concentration occurs in one side of the rock masses close to the trap door. Furthermore, the surface settlements are also related to the inclined angle, and the loosening zone in rock masses can be different from Terzghi’s theory [1]. Since, simulations have good agreements with the laboratory test , it demonstrates the applicability of DDA to explain the mechanical behaviors of tunnel, such as arching phenomenon, non-symmetrical earth pressure distributions acting on the trap door, and the surface settlement profile in the jointed rock masses. Dans cet article est décrite l’étude numérique du perçage d’un tunnel dans un massif de couches rocheuses jointes inclinées. La simulation à l’aide de l’Analyse de Déformation Discontinue (DDA), en faisant varier l’angle d’inclinaison des couches de roche, nous apporte des résultats en termes de distributions de contraintes et de comportement des couches, résultats qui sont ensuite comparés avec des résultats de tests en laboratoire. Les résultats confirment le fait que la DDA est capable de reproduire le phénomène d’arcage autour de la trappe lorsque la trappe s’abaisse. Les formes d’arcage varient selon l’angle d’inclinaison des couches de roche. Par ailleurs, lorsque les couches ne sont pas horizontales, la distribution de pression agissant sur la trappe est assymmétrique. La concentration de contraintes se produit du coté proche de la trappe. De plus, les tassements de surface dépendent eux aussi de l’angle d’inclinaison. En conséquence, les résultats de simulation sont en accord avec les tests en laboratoire, ce qui prouve que la DDA permet d’expliquer des comportements mécaniques du tunnel tels que l’arcage, les distributions assymmétiques de pression du sol sur la trappe, ainsi que le profil du tassement de surface dans la masse de roches jointes. Dieser Beitrag beschreibt eine numerische Studie über Tunnel im geklüftetem Fels. Das Verhalten und die Druckverteilungen in den unterschiedlich geneigten und geklüfteten Felsenmassen wird mit Hilfe des Discontinuous Deformation Analysis Programms (DDA) simuliert, und mit Laborversuchen verglichen. Die Resultate bestätigen, dass DDA der Gewölbewirkung im „Trapdoor“ Experiment gut reproduzieren kann. Die Form des Gewölbes, ändert sich mit unterschiedlichen Neigungswinkeln der Schichten. Bei geneigten Schichten entstehen unsymmetrische Druckverteilungen. Auch die Oberflächenabsenkung ist von dem Neigungswinkel abhängig. Die gute Übereinstimmung der Simulationen mit den Laborversuchen zeigt, dass die DDA-Methode gut geeignet ist, um das mechanische Verhalten von Tunneln, wie z.B. den Effekt der Gewölbewirkung, die unsymmetrischen Druckverteilungen bei geneigten Schichten, oder die Oberflächenabsenkung in geklüfteten Felsenmassen, zu erklären.

Jan 1, 2003

By Donna Kliche, Charles Kliche

It has been previously documented that various weather conditions such as wind direction and speed, cloud cover and, especially, temperature inversions can significantly affect the overpressure generated by a blast event (Siskind et al, 1980; Oriard, 1999; Siskind, 2000). The overpressure can be magnified downwind and reduced upwind; a change in the regular profile of temperature with elevation can magnify or focus the sound intensity at some distance from the blast event.

Jan 1, 2011

By P. Miranda, K. Le, G. Maes, R. Peters

"The Mount Milligan Mine, owned by Thompson Creek Metals Company Inc. (TCM), started operations in September of 2013. It is located between the communities of Fort St. James and Mackenzie and is the first major metal mine to open in British Columbia in 15 years. Based on reserves as of January 1, 2014, it has an estimated 22 year mine life with 2.1 billion pounds of copper and 6 million ounces of gold in reserves. Like all commissioning operations, there have been issues achieving design throughput and recovery due to flow sheet design, equipment failures, control philosophy, and reagent scheme. Efforts to improve overall mill performance include equipment modifications, reagent screening and testing, and grind size testing. Applying these changes to the mill and working closely with the mine has resulted in continuous improvement each month as Mount Milligan looks to achieve the nominal design capacity of 60,000 dry metric tonnes per day in the later part of 2015. Considerable focus is being placed into ensuring size reduction equipment is utilized effectively. Additional modifications and tests are being undertaken to steadily improve processes and alleviate restrictions in the mill. This paper will discuss the start-up and present ramp-up history of Mount Milligan, the current mill processes, and the steps taken to achieve expected production numbers.OPERATION BACKGROUNDMount Milligan is an open-pit copper and gold operation wholly owned and operated by Thompson Creek Metals. It is located approximately 155km northwest of Prince George, British Columbia, between the communities of Mackenzie and Fort St. James. The copper-gold porphyry deposit contains a Measured and Indicated Mineral Resource of 706.7 Mt at 0.18% Cu and 0.33 g/t Au, containing 2.84 billion lb. copper and 7.50 million oz. gold. Mine life is currently estimated at 22.1 years (“Feasibility Update – Mt. Milligan,” 2009). The mill is designed to process 60,000 dry metric tonnes per day and produce 400 dry metric tonnes of concentrate per day averaging 25.5% Cu and 40 ppm Au. Concentrate is delivered by truck and trailer to Mackenzie followed by rail to Vancouver for overseas shipping to various customers.Mount Milligan is considered a “zero discharge” operation meaning no process or surface water will be discharged to the environment. As well, stockpiling is very limited and is only permitted for a short period of time. This scenario presents several unique challenges. Scheduling of ore/waste production must be carefully planned as waste rock is used to build the tailings storage facility (TSF). Reagent selection is also important as persistent chemicals will have a tendency to build up in reclaim water which feeds the process water tank."

Jan 1, 2015

By C. E. T. White

Although trace amounts of Indium are found in many ores, commercial production of the metal has come almost exclusively from residues, flue dusts and slags generated by Zinc recovery operations. Our paper attempts to summarize the various approaches used to recover Indium from these by-products. Some comments on production and price trends are included as well as our views on future availability.

Jan 1, 1982

By Christopher Mark

This proceedings volume contains papers presented at technology transfer seminars sponsored by the National Institute for Occupational Safety and Health (NIOSH) on New Technology for Ground Control in Retreat Mining. The seminars were conducted at five locations: Uniontown, PA (March 26, 1997), Norton, VA (April 8, 1997), Pikeville, KY (April 10, 1997), Charleston, WV (April 17, 1997), and Evansville, IN (April 22, 1997). The papers presented here describe several new, highly practical technologies developed by the NIOSH Pittsburgh and Spokane Research Centers3 to improve safety during pillar retreat operations. Two central issues are addressed: pillar design and mobile roof supports (MRS's). Proper pillar sizing is essential for safe pillar extraction. The Analysis of Retreat Mining Pillar Stability (ARMPS) program and its large data base of actual mining case histories are presented. LAMODEL, a second computer program, can be used for analysis of multiple-seam and other complex mining situations. Other papers address pillar design to avoid massive pillar collapses and the proper role of coal strength testing. MRS's have greatly improved safety where they are used for pillar line support. We studied the application of MRS's at 20 mines throughout the Eastern United States. Conclusions regarding the most effective section layouts, cut sequences, and support placements are reported. Field and laboratory tests of MRS's are also described.

Jan 1, 1997

THE Australian States and New Zealand have for many years provided instruction in mining, metallurgy, geology, and their allied subjects through their Universities and Schools of Mines. Though such education has been provided at considerable expenditure, there is no legal recognition whatever given to the holders of degrees, diplomas, or certificates granted by the authorities controlling these educational institutions. Certain of the, Australian States and New Zealand require, however, that mine managers and other officials employed by the mining industry shall 'hold' certificates granted by their respective Mines Departments.The position at present is that each educational institution is practically a law unto itself, and therefore in many ways there is a want of uniformity amongst institutions all aiming at the same result the training of mining men. The object of this paper is, in the first place, to point out certain aspects of this want of uniformity, and thereby how disabilities accrue. Some points in connection with the granting of State certificates will also be...

Jan 1, 1915

By Gray Mullins

This paper presents results from model and full-scale tests to assess the interface bond between a cast-in-place concrete seal slab and steel H-piles in cofferdams. Three different seal slab placement conditions - fresh water, salt water and bentonite slurry - were evaluated and the results compared against controls where no fluid was displaced by the concrete. Normal pile surfaces were investigated. Additionally, the situation of ?soil caked? piles was also tested. In the model tests, eight 15 cm deep, W6 x 15 sections were used for two different embedment depths of 1.5d and 2d, d being the depth of the section. In the full-scale tests, 16 specimens 35 cm deep (W14 x 90 sections) were tested with the embedment varied between 0.5d-2d. The results show that significant bond stresses developed even in the worst placement condition. Recommendations made for revising current values in specifications have already been implemented by the Florida Department of Transportation.

Jan 1, 2013

By Luis v. Coppa

Since its inception in 1910, the Bureau of Mines has been the principal Federal agency involved in ore reserve estimations, using such traditional methods as polygons of influence and variations of inverse distance weighting While adequate for estimating the average are grades in a mining block or section, these methods do mot, however, provide a consistent way of quantifying the reliability of the estimates. This report describes a technique for enhancing ore reserve estimations using geostatistics, the methodology of which combines the spatial and random aspects of geologic phenomena into a formal theoretical framework for deriving the estimation variance of ore reserves. Correctly used, geostatistics enables confidence intervals to be placed around ore reserve estimates calculated from drill hole data. A geostatistical software system was obtained -From the U.S. Geological Survey and installed, aster slight modifications, on the Bureau's Wang computer. System testing and validation was conducted using a simple cast-book-type example. This was then followed by variogram analysis, point kriging and block kriging of data from a previously worked section of a uranium mine.

Jan 1, 1984

By A. T. Yu

On March 18, 1964, the 52,000 dwt ore carrier M/S Houn Maru called at the port of Coquimbo, Chile, on its maiden voyage to take iron ore to Japan. This marked the first time a vessel of this size ever arrived at Coquimbo, and the event promises to drastically accelerate henceforth iron ore exports from Coquimbo province. This was made possible by the use of a versatile shiploading system recently installed by Cia. Minera Santa Fe. Coquimbo has no mechanized loading facilities other than six conventional 5-ton cargo cranes. Limited space on shore further complicates the stocking problems. To make the best of what is available, a meticulously organized semi-hand-loading system has been developed through the years.

Jan 5, 1964

The goal of the Bureau of Mines diesel engine research program is to reduce exhaust emissions and minimize the risk of fires and explosions caused by the use of diesel- powered equipment in underground mines. This program has led to a fundamental understanding of the problems and to solutions that allow diesel equipment to be used safely and effectively. This volume contains reports of the presentations made at the Bureau Technology Transfer Seminar on Diesels in Underground &fines given in Louisville, KY, and Denver, CO, on April 21 and April 23, 1987. It also contains three reports of related research, not presented at the seminar, which highlight the significant achievements of a joint US.-Canadian research program on diesel emission control technology for underground mines. Topics covered in this volume include discussions of industrial hygiene problems associated with the use of diesels, accident statistics, fire and explosion control systems, measurement of diesel pollutants, emission control techniques including engine maintenance, fuel additives, diesel particulate filters, and ventilation of diesel sections. An alternative to diesel power, the hydrogen-powered mine vehicle, is also described.

Jan 1, 1987

By Mark G. Lafontaine

Underground 802.11 wireless communications has become widely adopted for automation and communication purposes but maximizing the wireless signal presents many obstacles given the harsh environment as well as the presence of materials and conditions that can reduce signal propagation. Changes in elevations and curvatures in ramp to drift transitions also affect the wireless signal. Based on the requirements of wireless applications such as voice, data, or location tracking, the wireless site survey is the key tool for measuring and predicting signal strength and signal-to-noise ratio. These readings help determine the maximum distance between access points in order to sustain an overlapping wireless signal where required. This paper describes the methodology and tools used for measuring 802.11 wireless signal strength in an underground mine environment in Northern Ontario. The physical characteristics of the mine and the actual recorded wireless signal data will be presented in order for the audience to gain an understanding of the factors that affect signal throughput. Antenna selection used for the site survey will also be discussed as it played a key role in propagating the wireless signal.

May 1, 2013

By R. G. Burn

"A brief outline will be given of the concept of risk and its implications with regard to investment in exploration. The relationship between risk and decisions under uncertainty will be examined as a prelude to identifying those factors which contribute to exploration risks:consideration of the effects of corporate objectives (e.g. survival, expansion, diversification) on exploration strategy and ultimately on success or failure, exploration and mining as an investment (the relationship between risk and reward) and the desired return on investment; exploration odds, funding levels, staying power, financial exposure and the concept of gambler's ruin;origins of uncertainty in exploration decision-making-man-made risks and natural hazards; the nature of introduced constraints at each exploration decision stage and their effect on the rate of success;improving the chances of success and the invest reduction of risk through sound exploration strategy, effective project generation and efficient target detection capabilities."

Jan 1, 1984

By E. H. Burroughs

This bulletin is the fifth in the series of petroleum bibliographies publis:\:l.ed by the Bure.au of Mines, Bulletins 149, 165, 180, and 189 being compilations for the years 1915, 1916, 1917, and 1918, respectively. In this bulletin the same general plan has been followed in arranging the references, but a few changes and additions have been made in the classification.

Jan 1, 1923

IN December, 1905, a Forwood down-wheeler grinding pan (5 ft dialmter), and similar in design to those in use on the Kalgoorlie goldfields, was installed for experimental work in connection with fine grinding jig tailings.The galena remaining in this product is very finely (closely) mechanically disseminated throughout the blende and gangue, rendering fine crushing imperative for its liberation. A reswne of the milling process in vogue at the old mill will enable the series of operations to be more closely followed. The ore at the South Mine assays, on the average-lead...

Jan 1, 1909

By Rixon K. L

Hargraves (1983) has reviewed the phenomenon of instantaneous outbursts of coal and gas with special attention to Australian occurrences. The purpose of this discussion is to highlight some problems and omissions in his review that reflect particularly on the authors' structural geological investigations of outburst-prone coal seams.It is surprising to find that much of the authors' reported work has either been glossed over or the results distorted by Hargraves (1983) and it is, therefore, important to clarify the contribution that structural analysis of coal seams can make.For many years it has been known that faults provided preferred loci for gas outbursts (for example, Briggs 1920-21) but the roie that faults played in outburstprone seams was unclear. The present authors reviewed the association of faults and outbursts drawing upon local investigations and the world-wide literature (Shepherd et aI., 1981), and discussed some wideranging aspects that result from the high coincidence of faults and outburst sites. Without repeating large segments of this article the authors will discuss four aspects of coal seam faulting and fracturing.

Jan 1, 1983

GENTLEMEN, lt is with much pleasure I meet you tonight at this the second meeting of the Australasian Institute of Mining Engineers, held in Western Australia, and I sincerely thank you for the honour you have conferred upon me in electing me as your President. I greatly appreciate the distinction, and will endeavour to fulfil the duties of the office to the best of my ability, and hope to prove a worthy successor to those gentlemen who have held the position before me. On behalf of the local members of the Institute, I extend a hearty welcome to the members from the other States of the Commonwealth, who have come so far to attend this meeting, and also to the non-members whom we have invited this evening. We are especially pleased to have Mr. Gregory, our Minister of Mines and Railways, and the Government and School of Mines officials with us; and I take this opportunity to thank the Premier, Mr. Gregory, and the Government officials for the assistance given us, and for doing so much to make the visit of our members from the other States so pleasant and instructive. I have also to thank the Mayor and Councillors of Kalgoorlie for the courtesy and hospitality given to our members, which is much appreciated.I assume you want me to follow the time-honoured custom of giving a Presidential address...

Jan 1, 1909

By Donald A. Ranta

Every mineral project or mine is based on a geologic entity-an ore (mineral) deposit. A well-defined mineral deposit and its associated geologic characteristics are the only aspects of a project that cannot be altered. Mine plans can be modified to exploit the deposit using alternative approaches and yielding similar results. A variety of processing methods also are often available producing generally comparable results. Major modifications can be made to other aspects of the project without substantially changing project economics. However, all engineering and metallurgical aspects of a mine must be accommodated to the spe¬cific location and geologic characteristics of the deposit. Geologic data and interpretations form the foundation for both mine evaluation and mine production by providing esti¬mates of reserves and essential information for mine planning and process design or control. Proper geologic work requires a keen awareness of and an ability to anticipate the technical requirements of geotechnical engineers, hydrologists, mining engineers, metallurgists, and other specialists. Geologists are inte-

Jan 1, 2008

By Thomas G. Murdock

The possible contribution of an improved mineral economy to the further advancement of the lesser developed regions of the world is a vital consideration today. Many of the newly independent countries recognize the problems and the challenge involved in orderly development of mineral resources. Some countries are inventorying resources, planning development, and encouraging local and foreign participation. The Malagasy Republic, composed of the island of Madagascar and the immediately adjacent islands, formerly the French Overseas Territory of Madagascar, is one of the members of the French Community which achieved independence in 1960. It is making real progress towards improving its mineral economy, an effort particularly remarkable considering the generally unfavorable geographic location of the area with respect to world markets and what is, after all, a comparatively sparse economic mineralization in the light of discoveries to date. Most of the development of the Malagasy econorny before independence was fostered by French private enterprise, although the State participated in some ventures. Since independence, the Government has encouraged private investment from a variety of sources through favorable legislation and has indicated that legitimate investment projects that will further advance social and economic programs will be welcome.

Jan 1, 1963