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By P. Schmieder

"The close vicinity of mining companies to other sites that are used for commercial and residential purposes or to areas under conservation as well as the fact that the people become more and more sensitive to emissions have led to a negative attitude towards mining operations in the neighborhood. It is above all the use of drilling and blasting techniques that give rise to objections, in the course of which demands for more environmentally-friendly production methods have been voiced. It is in this context that production methods without the use of explosives are considered as an option. After all, the use of such production methods is the only alternative for some quarry operators. The question is what are the true benefits of these techniques and what is the relation between a possible improvement of the environmental effects on the one hand and the technological potential as well as the costs on the other. It is intended to assess the mining techniques for solid rock in their entirety. This paper will therefore look at the aspects for assessing mining techniques in the context of their environmental impact and the costs."

Jan 1, 2005

By Eldridge Haynes

IF you ask the average American to define 'total war' he is apt to fumble for an answer. But in Britain everyone knows the answer, because Britain has mobilized its total labour force, including women. If we were to match, proportionately to our population, Britain's mobilization of labour, we should have 60,000,000 people working full time in the armed services, civilian defence, and war industries. Actually we have fewer than 35,000,000 so employed. In Britain two out of every three persons between the ages of fourteen and sixty-five are so engaged. For the first time in the history of any democracy Britain conscripts women for service in the army, navy, and air force. Two hundred thousand British women have been conscripted for the army, known as ATS, meaning Auxiliary Territorial Service. There are more women in the air force than the total personnel of the RAF at the outbreak of the war and almost all of the land base jobs of the British navy are now handled by women. In addition to cooking and office work, Britain's women soldiers and sailors are driving trucks and motorcycles, repairing motor vehicles, packing and repacking parachutes, installing, inspecting, and maintaining gun equipment and ammunition of combat planes after each raid, raising and lowering barrage balloons, forecasting weather, manning harbour craft, sending and receiving radio messages. A normal ack-ack unit is composed of 229 women and 189 men. The women man the gun height finders and predictors, give bearings, and signal to fire.

Jan 1, 1942

By I. Gombköto

Mining and mineral processing operations are usually generating huge amount of tailings. These tailings often gives lots of maintenance work in order to protect environmental resources from heavy metals slowly leaching out of tailing are due to Acid Rock Drainage (ARD) process. Handling leakage could be active or passive such as using of Permeable Reactive Barriers (PRB). PRB?s are used worldwide treating underground contaminations, using different type of matrix materials. All generally used matrix material has its advantages and disadvantages such as selectivity, sensitivity of precipitation generation or not satisfying hydraulic conductivity. Nowadays cheap and effective matrix material which is ignorant to pore plugging caused by precipitation within the PRB could be one solution to the demands of the industry. The authors have been carried out an investigation at University of Miskolc on lignite as high humid acid containing material for determining the ability of heavy metal adsorption and pore plugging resistance. Moreover, using hydraulic and chemical simulation methods, complete PRB dimensioning protocol based on new lignite matrix had been introduced. Within the frame of this paper the results are going to be discussed.

Sep 1, 2012

By Gift Makusha, Dave Minney

Anglo Coal South Africa mines coal for both the domestic and export market using open cast and strip mining methods. To establish a mine, a process is set in place to gather ever increasing amounts of geological and metallurgical data to confirm a proven reserve. Increasingly, geotechnical data are also included in this process to confirm that reserve is easily and safely mineable. The mine design process is an iterative one using a combination of numerical modelling and empirical data to arrive at a mining layout that is both, practical, productive and safe. In South Africa it is a legal requirement to compile a code of practice to combat rock fall and slope instability accidents and these have to be revised annually, reinforcing the iterative process of continual improvement. To ensure best practise occurs, all Anglo Coal operations are subjected to annual 2nd party audits and ad hoc 3rd party audit by independent consultants. This paper attempts to explain the process described above in a concise, but understandable manner. 1.0 GEOLOGICAL SETTING The Ecca sediments date from the Permian period and the coal deposits were formed in glaciated valleys on a basement of Dolomite, Ryolite or Granophyre rock types. The sediments overlying the coal deposits are typically flat lying and multiple bedded. The sediments consist of mudstones, shales and sandstones and are generally capable of forming stable highwalls given the time that they must stand up for. Anglo Coal extracts coal from the Witbank, Highveld and Vereeniging coalfields. The Witbank coalfields contain five seams numbered from the base upwards, 1 to 5 Seam; Highveld coalfield the 2 and 4 Seam and the Vereening area the seams are described as Top, Middle and Bottom seams. Coal deposited over the basement Dolomite formation display very erratic dips, as contemporaneous subsidence occurred in some instances over sinkholes that were forming, resulting in local thickening of the coal deposit and resulting in strata that dips toward the centre of the sinkhole.

Jan 1, 2006

By W. L. Thayer, K. A. Jonasson, R. D. Coleman, J. D. Hazlett, C. E. Capes

"Loss of coal fines in reject slurries limits the yield of coal cleaning operations. Difficulties in handling fines also limit the extent of physical cleaning in treating coals with finely-disseminated impurities. Selective oil agglomeration allows even extreme fines to be processed and offers some novel approaches for coal cleaning and utilization.The oil agglomeration process for the recovery and beneficiation of fine and ultrafine coal has now been commercialized by the Chemical Engineering Section/Chemistry Division of the National Research Council (NRC). This paper describes these activities to apply oil agglomeration and related fine coal technologies on an industrial scale. Pilot plant and large scale results are described, as well as aspects of agglomerate utilization in both wet and dry form."

Jan 1, 1988

By P. K. Sahoo, C. R. Ray, S. S. Rao

Good operation of Soderberg electrodes is dependent upon high quality electrode paste coupled with better electrode management procedures. Without having a good electrode operation, it is not possible to obtain the best outcome from the furnace. In other words that is a good way to say how important the proper electrode operation is. Good electrode performance depends on the slipping rate and current levels, which decides the shape of the baking curve at the level of just below the contact clamps. Negative curvature of baking zone in the central part is considered dangerous because shrinkage takes place outwardly creating abnormal stresses in the electrode. Soft breakages occur when the baking zone comes below the clamps and the casing cannot take the current. This paper deals with various factors affecting baking characteristics leading to soft breakages and also presents case studies in a closed 48MVA furnace with smelting for charge chrome. In case studies in a closed furnace, it has happened that the energy for baking at the low current operation before breakage has been lower than the actual slipping has demanded. At low current there should not be problem, but a problem can occur when the current for some period is raised above the current carrying capacity of the casing. So data for electrode operation in actual period was studied and presented in this paper.

Jan 1, 2007

By R. F. Favreau, Patrice Favreau

"A blast with explosives creates vibration waves in the zone around the blast.The prediction of the intensity of vibrations is important because people in the cinity demand that the vibrations do not disturb them, and society imposes limits on the vibrations. The U. S. Bureau of Mines (USBM) showed that the easurement of the particle velocity U predicts the risk of damage from vibrations. A currentapproach of blasters to monitor vibrations is to measure them with a seismograph at several distances S, and create a graph of U vs. S and the explosive charge “W” according to the equation U = K / (S / W)N where K and N are constants that depend on the blast method and the nature of the ground over the distance S. Though useful, this equation is empirical, and the results predicted from it are very variable, as shown by figure 1 which indicates that a prediction of U can deviate significantly from the actual value. Moreover, a minimum of two seismograph measurements at two values of S are required to establish the curve. However, here now exists another very convenient method to predict U; it is with the simulator Vibmas, which is based on the fundamental principles of how a blast reates vibrations. This simulator takes into account not only W but rather all the blast parameters, the type of explosive and the properties of the rock. Moreover, to establish the calculation of U as a function of S, only one seismograph measurement is required rather than two as for the USBM method. This last difference is important because it makes it easy to predict U not only as a function of S, but also as a function of the orientation of S. On the site this allows much safer control of the vibrations, and the use of larger explosive charges which reduce excavation costs. The article presents results from a field case at a hydroelectric project in Canada, where the deviation was very moderate. Use of this vibration simulator on the Web is very easy."

Jan 1, 2015

By S. L. May

Procedures for separating columbium and tantalum have been developed by the Bureau of Mines as part of a broad research program on the utilization of low-grade ores of columbium and tantalum, Columbium and tantalum compounds of greater than 99 percent purity have been obtained by application of the solvent extraction separation system: Hydrofluoric acid-sulfuric acid-methyl iso-butyl ketone. This system is unique in that it not only separates columbium from tantalum, but also separates these two metals from other metallic impurities. The system is effective for separating the metals irrespective of the tantalum and columbium ratio of the starting materials. Investigations in which the spent feed obtained from the initial coextraction step was recycled to the system indicated that efficiency was increased, and cost was reduced without impairing product purity. Continuous tests demonstrated that this solvent extraction system could be used in large-scale equipment without loss in efficiency or in purity of products. The separation of columbium and tantalum has been difficult because of the similarity in their chemical bahavior. Many methods have been proposed for separating these two elements, but most methods either did not achieve satisfactory separation or were tedious and time consuming. The Marignac process (3, 4)4 developed in 1866 was the only method used commercially until recently. This separation procedure is based on the difference in solubility in aqueous solution of potassium tantalum fluoride and potassium columbium oxyfluoride. Current commercial practice appears to favor solvent extraction as a method for separating tantalum from columbium (1). Several efficient methods for separating columbium from tantalum by solvent extraction (2, 9, 8) were reported earlier from this laboratory.

Jan 1, 1961

By P Breuer, X Dai, A Bergamin, D Hewitt

"Copper-ammonia-thiosulfate?leaching of gold has been researched for several decades as a potential alternative to cyanidation. However, this technology has not yet been applied commercially due to many challenges such as complex solution chemistry, reagent degradation and losses, system instability with losses of precious metals and difficulties in gold recovery from the leachate. Progress has been made at CSIRO in tackling some of these challenges including:better understanding and control of the leach conditions to minimise reagent losses whilst maximising gold recovery use of strong base ion exchange resins to recover the gold strategies to deal with polythionates that adsorb competitively with gold on ion exchange resins development and evaluation of process flow sheets.As a result there has been increased interest from the gold industry and renewed activities to develop thiosulfate based processes for gold recovery. One application area, which has been developed to the point of piloting, is the treatment of gravity gold concentrates using a copper-ammonia-thiosulfate leach with ion exchange recovery of the gold thiosulfate. This paper describes some of the advancements in the development of a potential process flow sheet for this application.CITATION:Dai, X, Breuer, P, Hewitt, D and Bergamin, A, 2013. Thiosulfate process for treating gold concentrates, in Proceedings World Gold 2013, pp 61-70 (The Australasian Institute of Mining and Metallurgy: Melbourne)."

Sep 26, 2013

By Gordon E. Fletcher

This Bureau of Mines report outlines the atomic absorption analysis of oilfield brines for barium, calcium, copper, iron, lead lithium, magnesium, manganese, potassium, sodium, strontium, and zinc, using the method of additions. The advantages of using atomic absorption are discussed. The method of additions was chosen to overcome large matrix interferences usually found in brines; techniques of overcoming chemical, ionization, and background interferences are also described. The method was used to analyze several hundred oilfield brines and found to be rapid and reasonably accurate. A solvent extraction method was used to concentrate lead, copper, zinc, and iron in low-level samples.

Jan 1, 1974

By Robb L. Swenson

Construction of foundations for the Skyway Segment of the San Francisco Oakland Bay Bridge required innovative techniques due to the mass of the structures being inserted and the unique subsurface of the Bay. Twenty of the pier structures required large sheet pile cofferdams. Eight other foundations were installed in open water without cofferdams at the deeper part of the Bay. This narrative will present the initial planning, as well as the stages of installation, for each type of foundation. The first section will discuss foundation constructability modifications made during the initial planning phases of the project. Considerable effort was expended by Caltrans, the owner, T.Y. Lin the designer, and KFM (Kiewit/FCI/Manson) the contractor in modifying the design to assure that required tolerance would be maintained during the installation of the foundations. The final section will describe the steps required for installation including: initial access dredging, installation of cofferdams, preparation required to install the footing boxes, footing box installation, foundation support pile installation, and pile to box connections.

Jan 1, 2013

By H. Ikeda

INTRODUCTION [Slide 1] The Role of the MMAJ Ladies & Gentlemen, it is a pleasure for me to be able to make a speech at this SME annual meeting, representing the Metal Mining Agency of Japan. [Slide 2] Today’s Topics In my presentation today, I would like to divide my topics into four parts. First of all, I would like to describe the current situation of Japanese non-ferrous metal mining and mineral processing industries in Japan. Secondly, the supply and demand of non-ferrous metals in Japan. Thirdly, I would like to spare some minutes on the overview of overseas development by Japanese mining companies. Finally, since some people may not be sure what the Metal Mining Agency is or what this Agency, I would like to briefly introduce the Metal Mining Agency of Japan.

Jan 1, 2001

By AIME AIME

FOR many years it has been the invariable custom of the Institute, in addition to its annual meeting in February, to hold a technical meeting in the fall in some mining or metallurgical center in the West. As the activities of the Institute have increased, and especially since the absorption 'of the American Institute of Metals, there have for a number of years been two fall meetings. Never before in the history of the Institute have there been three meetings in addition to the annual meeting in February; in 1920, however, three important fall meetings are to be held. The general Institute trip will be made this fall to the Lake Superior iron and copper country. Members will leave Buffalo on August 20 by steamer, visit the copper mines in and about Houghton, the iron mines of the Marquette and Iron Ranges of Michigan and the iron mines of the Mesabi Range in Minnesota, and' return to Buffalo by steamer on September 3. Technical sessions will be held at Houghton, Minneapolis and Duluth. For a long period it was customary for the Institute to visit the Lake Superior country about every seven years. This trip, however, will be the first visit since 1904. The unprecedented development in both copper and iron mining in this section during this period will make this trip of unusual importance. In addition, a notable series of papers will be presented.

Jan 1, 1920

By Michael B. Tessieri

With the increasing environmental demands and higher fuel efficiency standards on auto manufacturers, the use of aluminum in automotive applications is expected to show significant growth for the balance of this decade. Cast and wrought aluminum usage is reviewed by auto part, and alloy family for the year 2000 automobile. The analysis addresses the effect of this increased volume on the recycling infrastructure and identifies issues and opportunities, which will face the recycling industry.

Jan 1, 1995

By J Kinal, I Mitchell

Many flotation plants use pH to adjust the pulp chemistry of their system to achieve optimum separation. For example, in a sequential lead/zinc circuit the pH during sphalerite flotation is increased to 10.5 or greater to depress galena and pyrite, thereby improving selectivity for sphalerite. However, maintaining a pulp at a particular pH value does not necessarily provide the operator with an abundance of information regarding the chemistry changes occurring within a plant. This paper provides the reader with a number of pulp chemical observations in several plants, showing that the same trends are noted over time; however, the magnitude of the measured values do change. Further, the changes in magnitude are invariably associated with a change in mineralogy. Thus, is measuring pH enough? Can the Eh, dissolved oxygen and temperature be measured at the industrial scale reliably? And, are these measurements useful?

Jan 1, 2006

By G. W. Evatt

This paper presents the scientific framework underpinning the Resource Valuation and Optimisation Model (RVOM). The RVOM is a Real Options software package, which helps mine owners optimally plan their operations, understand their project risks, and make defensible valuations. This is achieved in the presence of both financial and physical uncertainty. The three key outputs from the RVOM are: Valuation, Optimal Decision and Probability of Decision, where a decision can include any combination of: normal operation, expanded operation, care and maintenance, and abandonment (and variants thereof). This paper presents a clear example of the RVOMs usage to a case-study gold mine.

Jan 1, 2011

By Albert Sauveur

It is delightful to read a technical paper like that of J. E. Johnson, The Effect of High Carbon on the Quality of Charcoal-Iron, presented in October, 1912, at the Cleveland meeting of the American Institute of Mining Engineers.' The clear, simple, and straightforward manner in which he describes his experiments and results makes you feel as if you had been, so to speak, at his elbow during the course of his investigations, while his method of procedure is so rational that you can fairly anticipate each step in the logical sequence of the tests performed. The following notes suggested by Mr. Johnson's paper are presented here in the hope that they may help, if only a mite, towards the final solution of a problem of considerable scientific and industrial importance. Physical Properties of Cast-Iron us. Its Ultimate Composition. Mr. Johnson writes that " an investigation along the lines of consumption showed that different irons have different characters totally independent of their analyses," and he declares that " the presence or absence of these elements [meaning carbon, phosphorus, silicon, and manganese] alone will not account for all, scarcely for a half, of the facts which have long been known." He further tells us that some foundries have " proved, by the most irrefutable tests, that they could take a certain iron of a given analysis and produce certain results," while with " another iron of the same analysis they could not produce these results at all." I feel confident that every experienced and thinking metallurgist will readily believe Mr. Johnson's statements and will share his views in regard to the hopelessness of inferring the

Jan 1, 1914

By Raymond P. Maloney

The Bureau of Mines investigated the White Mountain mercury deposit, in the Kuskokwim River Basin, to better determine the extent of mercury mineralization and to encourage its development by private industry. A program of diamond drilling, augering, bulldozer trenching, and sampling was carried on during four field seasons, from 1960 to 1963, inclusive. Significant amounts of cinnabar, with only trace amounts of arsenic and antimony, occur in dolomite over an area about 4,000 feet long and 1,500 feet wide. The deposit differs from other mercury deposits in the Kuskokwim River Basin by the absence of silica-carbonate and rhyolite intrusives. Small-scale mining was started in 1963 as the result of Bureau investigation and continued during the summers of 1964 and 1965. The investigations indicate that open pit mining might be the most feasible method of working this deposit.

Jan 1, 1967

By K. L. Money, R. R. Bleakney, R. H. Hanewald

The processing of EAF baghouse dusts, rolling mill scales, and belt grinding swarfs from the specialty steel industry will be reviewed. In addition, the INMETCO process has been modified so as to recover nickel, chromium and iron from many other waste materials such as pickling solutions, filter cakes, spent nickel and chromium plating baths, super alloy wastes, and nickel-cadmium batteries. INMETCO is the only North American company presently capable of recycling nickel-cadmium batteries by high temperature metals recovery.

Jan 1, 2000

By D. Hatfield, G. de Jager

"The rapid developments in computer vision and computational resources are creating new possibilities for the use of machine vision systems for industrial control. A number of commercial image analysis systems exist, and research into improved measurements of froth performance is ongoing. An integral part of the implementation of these systems is the validation of the relationship between image analysis measurements and flotation cell performance. This paper discusses the factors affecting concentrate flow and presents the results obtained from one such system with respect to its ability to estimate the flow of concentrate from a flotation cell.The relationship between froth flow speed and the rate of recovery of concentrate from a flotation cell was investigated on two industrial operations, both processing PGM (Platinum Group Metal) bearing ores. Results are presented that show a relationship between froth flow speed and concentrate yield."

Jan 1, 2003