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South Africa?s primary electricity supplier, Eskom, provides incentives to reduce power demand during critical times by granting capital through a Demand Side Management programme. DSM encourages the end user to review and optimize energy consuming systems and use capital, provided by Eskom, to purchase or modify the equipment required to achieve a load-shift. As part of the DSM agreement the mine ultimately acquires the capital equipment and benefits from reduced power costs, but in return is required to sustain the load-shift tactic for up to five years. The paper focuses on one DSM tactic, main fan energy management. In this case, reduced air flows during selected peak and off peak periods, results in a substantial reduction in peak power demand. DSM incentives provided capital for automated main fan control as well as improved control of the mine ventilation systems. To examine the work in detail Gold Fields Ltd Driefontein gold mine near Johannesburg was chosen as a case study.

Jan 1, 2009

By J. E. Shelton

Flotation tests are described on samples of two lowgrade nickeliferous ores of Oregon and Washington. The sample from the Congress mine, Ferry County, Wash., contained 1.2 percent Ni, occurring chiefly as millerite. The sample from the Shamrock mine, Jackson County, Oreg., contained 2.20 percent Ni and 0.78 percent Cu occurring chiefly as pentlandite, nickeliferous pyrrhotite, and chalcopyrite. The millerite in the Congress ore was concentrated by flotatioin with aulfydric collectors in a series of locked tests to recover 73 percent of the nickel as a 7 percent bulk concentrate. By successively regrinding and floating the bulk concentrate, it was further concentrated to 12.4 percent Ni at a recovery of 59 percent and 21.8 percent Ni at a recovery of 50 percent. Attempts at selective concentration of the copper-nickel Shamrock ore were only partly successful because of the intimate association of pentlandite and chalcopyrite. The nickel concentrate, which contained 86 percent of the nickel, had an analysis of 4.42 percent Ni and 1.03 percent Cu. The copper concentrate had an analysis of 18.8 percent Cu and 1.96 percent Ni and contained 48.5 percent of the copper. A bulk sulfide concentrate contained 92 percent of the copper and 01 per¬cent of the nickel and had an analysis of 4.17 percent Ni and 1.63 percent Cu.

Jan 1, 1956

By Robert C. Dyni

This U.S. Bureau of Mines (USBM) report summarizes a field demonstration of pneumatic backfilling technologies conducted at the abandoned Hillside Coal and Iron Slope in Vandling, P A. Researchers demonstrated two pneumatic backfilling technologies recently developed under the USBM's Abandoned Mine Reclamation Research Program, the Pneumatic Pipefeeder and the High-Efficiency Ejector. Both systems had previously been evaluated at the USBM's subsidence abatement investigation laboratory near Fairchance, P A. The objective of the demonstration was to fill 100% of the abandoned tunnel with backfill stone to prevent further subsidence. The Pneumatic Pipefeeder was used for 21 days, at a rate of 63 to 124 t/ d (69 to 136 st/d), to fill 88% of the tunnel. The High-Efficiency Ejector was used for 2 days, at a rate of 125 to 132 t/d (138 to 146 st/d) to fill the remaining 12% of the tunnel. The backfill placed by both systems was tightly compacted. The major problem encountered was wear on the polyethylene pipeline from the abrasion of the high-velocity backfill. The use of heavier steel pipe minimized the problem. A cost analysis for the entire project is given.

Jan 1, 2010

By N. K. Bohidar

Evaluation of the stability of a structure under given boundary conditions requires accurate knowledge of the state of stress as well as the mechanism of failure at the critical state of stress. This paper represents a part of the research done by N. K. Bohidar during 1965-1968 for his Ph. D. research in Mining Engineering at the University of Utah. It summarizes the determination of internal stress and failure phenomena around cylindrical openings in viscoelastic media subjected to lateral restraint and vertical uniaxial load. The conditions of lateral restraint and viscoelastic nature of the media represent conditions associated with subsurface openings in rocks. The financial assistance provided to the project from the University of Utah Research (Uniform School Fund), W. C. Browning Scholarship Fund, Earth Science Research Fund, and D. C. Jackling Loan and Scholarship Fund is gratefully acknowledged. The authors also acknowledge the assistance of S. Siugh, W. Jones, and K. McCarter during the project.

Jan 1, 1970

Paper written on project work carried out in partial fulfilment of B.Sc. Eng. (Extractive Metallurgy)degree The concepts behind support vector machines are very interesting both in theory and in practice, as they are based on a universal constructive learning procedure derived from the statistical learning theory developed by Vapnik. In this paper, their application to time series modelling is considered by means of simulated data from an autocatalytic reactor. In particular, reconstruction methods from non-linear dynamics are used to define a state space model for the process. Multivariate embedding techniques are compared to scalar embedding with respect to modelling. Keywords: System identification, Support vector machines, Multilayer perceptrons, Non-linear dynamics

Jan 1, 2003

By Serdar Aktaş, Burcu Nilgün Çetiner

According to critical statistical studies, antimony is one of the rarest elements in the world, and global resources could be exhausted by 2050. In light of these observations, its extraction will be costly due to poor-quality ore, deep mining, remote locations, and high energy consumption. In the present study, an alkaline leaching process was carried out on stibnite concentrate to evaluate the effect of reaction parameters on the percentage of antimony extraction. The leaching efficiencies of different sulfur and hydroxide sources were studied and compared to one another to create a better understanding of the reaction process. Kinetic models were investigated to identify the reaction pathway and calculate the activation energy. The activation energy of the stibnite dissolution was assessed as 19.13 kJ/mol using a two-dimensional diffusion-reaction model. The value of activation energy indicates the quantity of energy necessary for a reaction to proceed. As expected, potassium hydroxide leaching was significantly more successful than was sodium hydroxide; however, in terms of economics, the use of sodium hydroxide was found to be more cost-efficient. Interestingly, this finding indicated that caustic leaching is still the most effective method for stibnite extraction.

Jul 23, 2020

By Lilong Huang, Xiang Zhao, Yuan Long, Li Shi, Guowang Zhang, Xiao Xiao

"Vertical stirred mill is expected to upgrade the iron concentrate by further size reduced efficiently. The tests for fine grinding of iron ores from Baiyun Boyu iron ore, Baogang Goup, iron contained tails of Cu-Pb-Zn ore in Wanguo ore, Xiaoshalong iron ore in Qinghai were conducted in this paper. The data of appropriate grinding fineness, optimum grinding conditions and energy consumptions obtained from the test were used to select appropriate scale of the vertical stirred mill, optimize the parameters of the grinding process and upgrade the iron concentrate of the iron ore dressing plant or design the new ore dressing plant. Based on the laboratory tests, industrial system of regrinding and magnetic separation with vertical stirred mill as the regrinding mill in micro-fine grained iron concentrate upgrading has worked out very well. The grade of Fe in iron concentrates has increased to about 65.0% (by 4.0~6.5 point percent) when the iron concentrates were reground to designed fineness and the specific energy is 5.0~7.1kWh/t. The system of regrinding and magnetic separation is proven to be eco-efficient in iron concentrate upgrading."

Jan 1, 2014

By J. S. Stachulak

"The main ventilation design features adopted at Inco to safeguard personnel against the effects of fires are described in this paper. Measures taken to prevent and detect fires due to spontaneous combustion, and fires involving conveyor belts, are described in detail.IntroductionConsidering the over-all picture of present-day mining operations, the expenditure required to provide a proper system of mine ventilation and fife control should be regarded as a sound investment that will pay back in increased mining efficiency, improved safety, health, and morale of the miners.Mine ventilation control and mine fife detection and fighting are inseparable, because a ventilation system can spread deadly products of combustion just as efficiently as it does life-sustaining oxygen. Therefore, the possibility of a mine fife occurring is of particular concern.The first objective is to prevent a fife.The second objective is to design the ventilation system so that a positive fresh air supply can be ensured on each main level regardless of the location of the fife.The third objective is to be able to detect the fife at an early stage and to extinguish it before it can develop into a major fife. Accordingly, at Inco, very extensive measures are taken to prevent fires and to locate, isolate and extinguish them rapidly. To obtain an early warning, it is not sufficient to know that a fife has started, but it is also necessary to know where the fife is burning."

Jan 1, 1994

By J. S. Stacbulak

"The main ventilation design features adopted at Inco to safeguard personnel against the effects of fires are described in this paper. Measures taken to prevent and detect fires due to spontaneous combustion, and fires involving conveyor belts, are described in detail.IntroductionConsidering the over-all picture of present-day mining operations, the expenditure required to provide a proper system of mine ventilation and fife control should be regarded as a sound investment that will pay back in increased mining efficiency, improved safety, health, and morale of the miners.Mine ventilation control and mine fife detection and fighting are inseparable, because a ventilation system can spread deadly products of combustion just as efficiently as it does life-sustaining oxygen. Therefore, the possibility of a mine fife occurring is of particular concern.The flirt objective is to prevent a fife. The second objective is to design the ventilation system so that a positive fresh air supply can be ensured on each main level regardless of the location of the fife. The third objective is to be able to detect the fife at an early stage and to extinguish it before it can develop into a major fife.Accordingly, at Inco, very extensive measures are taken to prevent fires and to locate, isolate and extinguish them rapidly. To obtain an early warning, it is not sufficient to know that a fife has started, but it is also necessary to know where the fife is burning."

Jan 1, 1994

By R. L. Hopkins, H. T. Rall, H. J. Coleman, C. J. Thompson

Two methods were tested for separating sulfur compounds in certain petroleum fractions into types . Such separation is preliminary to identifying the compounds . Each method involved extraction of sulfides from petroleum sulfur concentrates . In the first method , the sulfur concentrate was reacted with methyl - ptoluenesulfonate to form sulfonium compounds from which unreacted portions of the sample were removed by washing with solvent . The sulfides then were recovered by heating the sulfonium compounds with anhydrous triethanolamine . The second method consisted of passing anhydrous hydrogen iodide into a n-butane solution of the sample cooled in dry ice , whereupon the hydrogen iodide adducted with the sulfides to form sulfonium compounds . These adducts separated as crystalline solids or , more frequently , as glassy viscous liquids . The sulfide was regenerated by adding water to the filtered sulfonium compound and was recovered by steam distillation or by extraction with pentane . These methods have been evaluated , using individual pure sulfur compounds and blends of sulfur compounds . They also have been applied successfully to separating sulfides from sulfur concentrates derived from petroleum fractions .

Jan 1, 1964

By Enrique Rubio Esquivel, Matías Fuentes Bustamante

The transition from open pit to underground mining represents a key strategic challenge in modern mine planning. This paper presents a multicriteria and multivariable methodology to plan such a transition, integrating technical, economic, environmental, and social considerations. The proposed framework focuses on risk reduction (de-risking) through the identification of alternative development paths, the use of stochastic simulation to model geological and technical uncertainty, and different mining strategies such as methods, production rates, sequence, etc. for ultimate underground implementation. The study summarizes the limitations of traditional planning methods—which usually treat the open pit and underground mine designs as independent processes—, also often it considers a single mining method and production rate for the underground option. Instead it is proposed an integrated approach that leverages synergies between both mining methods and scalable production rates. Also the proposed methodology incorporates the definition of critical variables (geotechnical, economic, and social, among others), the construction of multiple operational and technological transition paths, and the evaluation of each path under criteria of economic attractiveness and practical do-ability (capacity to be executed). Using simulation tools (SIMPLAN for operational performance and SIMVAL for economic evaluation), probabilistic distributions of the different path are obtained, enabling the quantification of the project’s Value at Risk (VaR). A subsequent multicriteria analysis weights the expected profitability against the feasibility of execution of each alternative, producing a decision matrix that provides a framework for evaluating the different project path. As a result, the proposed approach identifies OP→UG transition strategies that maximize business value by capturing remaining resources while minimizing financial and operational risks. Finally, strategic conclusions and recommendations for the industry are provided, emphasizing the importance of early transition planning even challenging the open pit sequencing of the latest push backs by introducing early underground operations. Future work includes strengthening the methodology—such as integrating real-time analysis and adaptive decision-making—and providing recommendations for its application in various mining operations. In summary, this paper delivers a technical and professional framework to guide mining companies on when and how to carry out a successful transition from open pit to underground mining, balancing resource recovery with financial, operational, and social security.

Feb 22, 2026

ON Oct. 5, 1926, the day before the general ses-sions of the fall meeting of the American Insti-tute of Mining and Metallurgical Engineers at Pittsburgh, a round table conference on the combus-tibility and testing of coke was held at the Bureau of Mines Experiment Station. There were about fifty present, with A. C. Fieldner, chief chemist of the Bureau of Mines, as chairman. The following organi-zations were represented: American Institute of Min-ing and Metallurgical Engineers, American Society for Testing Materials, American Gas Association, Eastern States Blast Furnace and Coke Oven Association, Gas and Fuel Division of, American Chemical Society, and Southern Ohio Pig Iron and Coke Association. In opening the proceedings, Mr. Fieldner explained that the meeting had been called at the suggestion of several members of the Institute and members of other organizations. The subject is of interest to the pro-ducer and the user of coke whether it be in a blast furnace, cupola furnace, house-heating furnace, open grate, gas producer, or in a water-gas generator. There has been much confusion on this subject largely because there is no common definition of combustibility. Does the blast-furnace superintendent, the coke-oven operator, and the fuel engineer have the same under-standing of the term "combustibility"? If a common understanding can be reached, many differences of opinion will disappear. COMBUSTIBILITY OF COKE R. H. Sweetser of Columbus, Ohio, disagreed with the statement of P. H. Royster, T. L. Joseph, and S. P. Kinney in Reports of Investigations, Serial No. 2524, of the Bureau of Mines, in which it was stated that the coke-oven op-erator cannot change coke combustibility by modifying oven practice. Mr. Sweetser held that the coke-oven man can change the combustibility of coke. Blast-furnace men know that coke that will burn easily with low pressure and will. come down in the regular way in the furnace can be pro-duced from a given mixture of coal. His idea of the combustibility of coke is the rate of flow through the com-bustion zone of the blast furnace. If the coke does not pass through in normal manner it is highly incombustible. H. J. Rose of the Koppers Co., Pittsburgh, objected to being pinned down so closely on this phase of the com-bustibility and incombustibility of coke. Coke-oven men are frequently obliged to change oven conditions to make a coke which gives blast-furnace men what they want. The size of the coke and the screening have an important bear-ing on combustibility, and there are many cases on record where by simply changing the different sizes of the coke, everything worked smoothly, and that is a much more combustible coke.

Jan 1, 1927

By R Moreby, J Kok, L van den Berg

The high production rates achieved from mass mining methods such as block caving, sublevel caving and longwall mining require large conveyor belts, trucking loops (diesel/electrical) and rail systems for ore handling. However, the ore handling systems used in mass mines introduce a significant amount of heat into the overall ventilation system, which may be problematic at depth or in mines located in hot climates.In particular, the heat load from a conveyor system is not always well understood and consists of various components, including frictional heat from idlers, heat from electrical motors, heat from the drive train and heat from broken rock transported on the conveyor system. This paper presents results from a study that investigated the heat introduced to the ventilation air from a large conveyor system. The conveyor system transports ore with a maximum virgin rock temperature of 41°C from a depth of over 1 km. Air, belt and rock temperatures were measured in the conveyor system to evaluate the distribution of heat loads.CITATION:van den Berg, L, Moreby, R and Kok, J, 2015. Heat load estimation from conveyor systems in mass mines, in Proceedings The Australian Mine Ventilation Conference, pp 63–70 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Aug 31, 2015

By O. C. Blade

This report on the properties of aviation gasolines and aviation jet fuels produced in the United States during 1953 was made under a co-operative agreement between the American Petroleum Institute and the Bureau of Mines of the United States Department of the Interior. Analytical data are presented for 101 samples of aviation gasoline which include, for the second time in this series of reports, data on some samples of grade 108/135 aviation fuel. Data also are given for 32 samples of aviation jet fuel. The analyses were made on samples typical of the manufacturers' production in their laboratories and the results sub-mitted to the Bureau of Mines for compilation. The products of 19 manufacturers of aviation gasolines and of 19 producers of aviation jet fuels are represented.

Jan 1, 1954

By Robert G. Bottge

The Bureau of Mines has engaged m a program to determine the availability of land for mineral exploration and development in Alaska. Land availability, based on ownership and Federal and State laws and policies, is compared with mineral terranes and mineral deposits. This is the fifth of six regional studies, which cover the State with a comprehensive set of maps and data compilations. This study covers an area of 112.3 million acres in western Alaska. In July 1986, 41.0 million acres, 37% of the study area, were available for mineral exploration and development; 14.6 million acres, 13%, were available with restrictions; and 56.7 million acres, 50%, were unavailable. Nearly 65% of the unavailable land is classified as national parks, preserves, wildlife refuges, and wild and scenic rivers. Of the 34.0 million acres of mineral terranes that underlie the study area, 12.9 million acres, 38%, are available for exploration and development; 3.6 million acres, 11%, are available with restrictions; and 17.5 million acres, 51%, are unavailable.

Jan 1, 1988

By J. Ji

Oxygen requirement during acidic pressure oxidation of sulphide concentrates can he as high as 800 kg/(m3.h) in the first compartment of an autoclave when the total oxidation residence time is shortened to 30 minutes. To achieve such a high oxygen transfer rate while maintaining satisfactory oxygen utilization, a pilot plant campaign was launched at the Placer Dome Research Centre in 1998 to measure the oxygen mass transfer coefficient in a 5 m3 pressure vessel at a total pressure close to 500 psig with a 30 HP gassing agitator. Maximum oxygen flowrate to the pressure vessel was designed at 3 600 kg/h. In this paper, a great deal of information is provided on the gassing agitator, pressure vessel. measurement procedure and results. Without oxygen sparging, the oxygen mass transfer coefficient is 2 600 h-1 with a mixing power input of 5.0 kW/m3 in solution. With oxygen sparging, the oxygen mass transfer coefficient increases to 3 500 h-1 with a mixing power input of 4.0 kW/m3 in solution.

Jan 1, 2004

By M Stewart

In January 1994, Macraes Mining Company started a new phase of exploration to find additional resources along strike and down dip of identified resources for a mill that was being expanded from 2.1 Mtpa to 3.2 Mtpa. At 30th June 1997 a total of 456,784 m in 3,627 holes had been drilled at the Macraes Gold Project with approximately 325,000 m in 2,100 holes drilled in the latest phase of exploration. This necessitated the construction of resource estimates on a more frequent basis and resulted in the formation of a resource modelling team, assisted by Snowden of Perth. Since April 1995, 14 separate resource estimates have been completed. At Macraes, resource estimates are built using Medsystem/Minesight software. The geological interpretation is converted into a set of three dimensional wireframed solid models which are used to code drillhole composites and blocks in a block model. The interpolation method of indicator kriging is used to interpolate grade into the blocks. Classification into measured, indicated and inferred categories is on the basis of geological confidence and drill spacing. The resource estimate is reconciled against grade control polygonal estimates on a bench by bench basis and on a monthly basis. Grade control estimates are reconciled monthly to mill production. For the period 30 June 1995 to 30 June 1997, the resource estimates have under predicted tonnes by 4% and grade by 1% to under predict ounces by 5% at a 0.5g/t cut off. At ROM sulphide cutoff grade, the models have over predicted tonnes by 5%, under predicted grade by 5% to over predict ounces by 1%.

Jan 1, 1997

By A. F. Colombo

The western Mesabi range nonmagnetic taconites containing about 34 percent Fe were evaluated by the Bureau of Mines in a 900-pound-per-hour pilot plant employing a selective flocculation-desliming-cationic flotation technique. The flotation step was a reverse flotation process and involved the flotation of the gangue minerals. The objective of the research was to increase the availability of domestic raw materials for the iron and steel industry. The beneficiated ores yielded concentrates containing 62 to 64 percent Fe and less than 5.5 percent Si02 with accompanying iron recoveries that averaged about 75 percent. Comparable flotation results were obtained with either fresh or 80 to 90 percent reclaimed water. Recycled waters having turbidities as high as 5,000 ppm Si02 did not affect the flotation process. Reclaimed waters containing residual calcium contents of less than 10 ppm gave better flotation concentrates than those containing 15 ppm.

Jan 1, 1976

By Mary Ellen Large

This publication of Deep Foundations Institute (DFI) is intended to provide project owners, design engineers and construction professionals with guidelines for selecting cutoff wall and barrier systems and a general introduction to their methods of construction. Three categories of cutoff wall and barrier construction technology (excavated cutoff systems, in situ techniques, and driven cutoff systems) are presented and parameters for evaluating their design and construction are discussed. The information presented was compiled from the opinions of practicing engineers and construction specialists from the DFI Slurry Wall Committee.

Jan 1, 2021

By Victor Benavente

La lixiviación es un proceso hidrometalúrgico que permite obtener el cobre de los minerales que lo contienen, aplicando una disolución de ácido sulfúrico, agua y agentes oxidantes. Este proceso consiste en que los minerales son sensibles al ataque de soluciones ácidas y oxidantes. En ese sentido, el objetivo del texto fue determinar la respuesta de los sulfuros secundarios de cobre a la lixiviación ácida y oxidante utilizando cloruro de sodio como portador de cloruro al sistema de lixiviación. El desarrollo de las pruebas y la ejecución de las mismas, definiió el proceso de lixiviación para minerales sulfurados de Minera Pampa de Cobre.

Sep 12, 2011