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By R. L. Pozzo

The electrochemical nature of mineral-grinding media interaction in the wet grinding of one and two sulfide mineral ores was investigated with regard to the flotation behaviors of the minerals. Two iron sulfides (pyrite and pyrrhotite) and mild steel were used to represent the sulfide minerals and the grinding media, respectively. Galvanic currents in two-and three-electrode combinations under abrasive and non-abrasive conditions were correlated with the floatabilities of these minerals under corresponding conditions.

Jan 1, 1988

By S. Acar, M. Botz

Introduction In 2007, Newmont Mining Corporation will begin construction of a milling and cyanidation leaching circuit for the Yanacocha site in Peru. Ore to be processed in the circuit contains a relatively high level of cyanide-soluble copper, and as a result, leach solutions are expected to contain elevated levels of copper and WAD cyanide. As the means of controlling copper levels in leach solution, a circuit will be installed to precipitate copper sulfide from barren solution using sodium hydrosulfide. In addition, a circuit will be installed to recover cyanide from barren solution, with recovered cyanide to be returned to the leaching circuit and treated solution to be utilized as make-up in existing heap leaching facilities. As needed to support design of the copper precipitation and cyanide recovery circuits, pilot testing was conducted in 2005 to determine preferred operating conditions and evaluate the performance of the processes. This paper presents results from the pilot testing where 99% copper reduction was achieved and 95% to 98% cyanide recovery was achieved.

Jan 1, 2007

By G. Swartz, R. J. Brison, R. A. Wyman, J. P. Vandenhoeck, S. E. Khalafalla

Magnetic fluids are commonly composed of ultrafine submicron particles of magnetite (Fe3O4) dispersed in either a kerosene or a water carrier medium with oleic acid as a protective colloid. The unique property of these fluids is that when the magnetic particles are attracted to a magnet the carrier medium moves along with the particles so that the liquid also appears magnetic. The availability of a fluid whose gross behavior changes sharply in a magnetic field without affecting its rheologic characteristics is becoming critical for many technologic applications. About two gener¬ations ago suspensions of relatively large, micron-sized ferromagnetic particles in oil proved useful in clutches, brakes, and dashpots. These were called magnetic clutch materials, and their viscosities were highly dependent upon the applied magnetic field, in contrast to true mag¬netic fluids which retain their fluidic characteristics under all applied fields and field gradients. While the term "ferrofluid" was used by Rosensweig and Kaiser&apos; to designate a magnetic colloid composed of a dispersed magnetic ferrous material, the more general term, "mag¬netic fluid," is preferred. This is because these fluids may contain ferro- or ferrimagnetic substances, such as cobalt, nickel, gadolinium, dysprosium, or magnetic ferrites in carrier liquids, such as hydrocar¬bons (kerosene), silicones, water, fluorocarbons, etc. Preparation of Magnetic Fluids Magnetic fluids were first prepared by Papell and Faber, at the NASA Lewis Research Center, Cleveland, Ohio, by tumbling ferrite materials for several weeks in a carrier medium (such as kerosene) and a dispersing agent (such as oleic acid) with steel balls. Rosensweig et al.1 compared the stability of their ferrofluids obtained from both metallic iron and the magnetic oxides of iron, Fe3O4 and yFe2O3. They found that, although the saturation magnetization of iron is 3.5 times greater than that of magnetite, its colloidal solutions deterio¬rated much more rapidly. The iron particles were undoubtedly rapidly oxidized to a nonmagnetic state due to the enormous surface area of these colloidal particles. Because the properties of these fluids are highly dependent on particle size and may acquire opposite characteristics by small incre¬ments in that size, more controllable methods of preparation have been developed recently by Khalafalla and Reimers.6 In one method metastabilized pyrophoric wiistite is ground to colloidal size in a kerosene oleic acid mixture, and then it is disproportionated to colloi¬dal magnetite and iron at temperatures just below the eutectoidal temperature of wüstite stability (570°C); thus, t < 570°C 4 FeO t > 570°C Fe + Fe30, (1) Because of its antiferromagnetic characteristics, the precursor wüstite is much easier to grind than magnetite. Another method3 avoids grinding entirely and utilizes a peptiza¬tion technique from ferrous materials in the molecular state of aggrega¬tion. This latter procedure has resulted in preparation of strong fluids at considerable savings in cost.

Jan 1, 1985

By Edward J. Adams

In recent years, there has been a shortage of individuals trained in the technical skills entering the mining industry. The university and industry, both indicating their concern, have joined efforts in an attempt to do something about this situation. An example of such an effort is the Pennsylvania State University&apos;s Student-Trainee Program in Mining Engineering, now in Its third year. The program is a five-year plan in which six months of schooling and six months of on-the-job training are alternated, climaxed by the student trainee earning a Bachelor of Science Degree in Mining Engineering plus two years of practical experience. The student trainee accepts the work-study plan as a satisfactory method of receiving a thorough education and preparing fog a career in the mining industry. Inasmuch as the work and study-periods are alternated, the trainee has an opportunity&apos; to integrate his practical experience with his academic knowledge. He receives a chance to observe others perform she duties of the profession he is preparing to pursue, and he regards this as an essential part of any such cooperative effort. Even though there are some disadvantages, the trainee feels that the advantages of the program are definitely more decisive.

Jan 1, 1963

By Z. Eisenstein, H. Heinz

INTRODUCTION Contemporary underground transit systems often require cross sections which are not adaptable to shield tunnelling. Due to the frequently large dimensions of these cross sections, which are normally situated at shallow depths and in soft ground, full face advance is not feasible because of ground control and construction requirements. Ground deformation and face stability are controlled by "staged excavation", which consists of sequentially driving smaller, specially arranged, individual headings hence avoiding full-face excavation. Shotcrete is normally used for initial support and these tunnels are frequently described as applications of the New Austrian Tunnelling Method (NATM). Figure 1 illustrates the relative size of large cross section tunnels with respect to conventional shield tunnels. Within the scope of this paper, &apos;large&apos; cross sections are defined as those whose continuous (i.e., without intermediate pillar support) cross sectional excavated area exceeds 60m2. This definition includes most double track highway, railway and subway tunnels, subway stations and some single track railway tunnels. Excavation schemes which have been more frequently used for continuous cross sections (i.e., with no intermediate pillars) are presented in Figure 2. This classification is an extension of that presented previously by Eisenstein et al. (1986). The symbols used for classifying the excavation schemes are formed by the letter T (for "type"), followed by a number, which represents the number of excavation stages fully embraced by a shotcrete ring, termed "cells" by Lessmann (1986). The numbers inside the cross sections in

Jan 1, 1989

By J. K. Phiri

Copper mining is the main activity in Zambia and is confined to the large scale operations, mainly on the Copperbelt. The Copperbelt covers an area of size l00km by 50 km with a total of 10 underground and 5 open-pit mines operated by Zambia Consolidated Copper Mines (ZCCM) Limited. Most of the operations in these mines involves drilling and blasting. The loading of broken materials is by both manual and mechanical operations. Among the many risk factors associated with mining on the Copperbelt, is the occurrence of Pneumoconiosis which in the recent past has become quite prevalent and thus an important occupational health hazard for the industry. This study was carried out with the aim of establishing trends of pneumoconiosis incidence through the annual data collected by Pneumoconiosis Medical and Research Bureau of the Ministry of Health in Zambia, so that a basis could be formed for future research work. The study covers over 1,000 certified cases of Pneumoconiosis between 1960 and 1990

Jan 1, 1993

By M. J. Richards, T. X. Ren

Determination of the state of an underground fire plays an important role in fire fighting, rescue and reopening operations. This is normally achieved by the analysis and interpretation of fire gases taken from the fire zone. However, drawing conclusions from gas analysis is not an easy task and needs specialist skills, expertise and experience that are usually beyond the knowledge of the officials in a mine. The complexities of a mine fire and the uncertainties of available information often make effective fire fighting decisions difficult if not impossible. This paper describes a knowledge based expert system that can aid in the diagnosis of sealed coal mine fires. Using a commercially available shell, the expert system has been designed to accommodate a series of diagnostic rules replicating the reasoning logic that would be used by human experts. The system allows the diagnosis of explosibility of the fire zone and trends of various fire ratios to be easily visualised for decision making. By continuously analysing the incoming information, the system is able to provide a rapid assessment of the situation of a sealed mine fire prevailing under specific mining and geological conditions. In addition, short term trends in fire behaviour can be predicted and possible fire control actions recommended. An example is given and shows how this system can be used as an analytical tool in various ways to assist the combating of coal mine fires. Further development of the system is discussed.

Jan 1, 1993

By Paul J. A. Lever, Robert H. King

Human operators, geological conditions, equipment changes, mining sequences, and roof conditions are some of the continually changing operating conditions that drive a dynamic mining environment. These dynamic characteristics make it difficult to automatically analyze mining data because attributes change as the mining environment changes. Mine monitoring systems could provide mine managers with much more useful information than they do presently, if automatic analysis were possible. Automatic analysis of sensor data is also key to autonomous mining systems. This paper describes artificial intelligence (AI) and sensor fusion based sensor data analysis techniques developed over the past four years. These techniques were used to classify machine operating events by continuously monitoring machine power usage in a continuous miner section at an under- ground coal mine. The result is a report similar to an industrial engineering time study. First, numerical pattern classification techniques broadly identify operating events. However, domain knowledge about inter-machine and intra-machine interactions is necessary to identify and refine dynamic event boundaries. By implementing AI and sensor fusion based techniques we are able to classify machine events more accurately and recognize more specific events. These techniques could easily be applied to many different mining sensor data applications

Jan 1, 1993

By Gianfranco Ferrara, Carlos A. Guimaraes, M. C. Williams, T. P. Meloy

Presented is a method of continuously producing very narrowly sized particle streams. Currently Sieve Cascadography is a batch method of analyzing particle shape - a form of particle chromatography. This paper introduces and analyzes the continuous Sieve Cascadograph, a device that enables a series of narrowly sized particle fractions to be produced continuously. Properly designed, the continuous Sieve Cascadograph will produce many product streams of particles with as little as one percent difference in particle size within a given size fraction - an order of magnitude better than existing technology permits. By varying operating conditions, the size of the output fractions may be varied.

Jan 1, 1992

By R. D. Herron

Mining coal under deep cover conditions is certainly the proper phrase to use in describing one of our newest operations. Located in the southwest corner of Virginia is this operation which is the Beatrice Mine of the Beatrice Pocahontas Company, a joint venture of Republic Steel Corporation and Island Creek Coal Company. The mine is working in the No. 3 Pocahontas seam in an assigned area of over 9500 acres containing over 60 million tons of recoverable, high quality, low volatile coal. The site of the mine opening was at Keen Mountain, Virginia, where the seam lay 1350 feet below the surface. This depth, greater than anything attempted thus far in the coal industry on this continent, would pose some problems, we felt, with which we had not previously had to contend.

Jan 1, 1968

By V. Carabias-Hütter, A. J. Basu

The paper aims at promoting sustainability assessment and reporting into practice using a globally acceptable set of guidelines and a common framework for internal and external reporting at a project/site level. Indicators are used for measuring performance, and this paper addresses development and implementation of performance indicators for sustainability assessment and reporting at local as well as global levels. The selection of a proper set of indicators is a challenging task. The indicators selected should provide the expected information for making right decisions. Relevant and credible sustainability reporting supported by a consistent performance indicator system can be the starting point for benchmarking environmental and social performance for the natural resources sector.

Jan 1, 2004

By A. Andreas

The transportation of mine products incurs a cost which can have a significant bearing on the competitive position of the product. This statement not only holds true for the transportation of the finished product but certainly as much for the in- plant haulage of the raw materials. Extensive literature is available both in North America and Europe on all aspects 02 these questions and to cite only a few of them: Pipelining of slurries, oil and gas, shipping of minerals and oil from the Arctic by icebreaking tankers, airlifting of metals or concentrates, etc. This paper is concerned with movable crushing plants as opposed to stationary and their influence on the in-plant transportation, that is trucks vs. belts.

Jan 1, 1973

By A. Goulsbra, S. Gregory, P. Gelfil, V. Martins, R. Dunne

As a general rule for gold treatment the presence of reasonable amounts of 'coarse' free gold will dictate the use of a gravity circuit. The actual particle size of gold that constitutes the por­tion of' coarse' free gold can vary widely. The larger its size the more troublesome it is, mainly because of the tendency for this gold to quickly settle out from slurries in regions of relatively low velocities. There are a multitude of places where 'coarse' gold can find a resting place, namely, in chutes, between and behind lines, in pump hoppers and in pumps themselves. Fortunately, the problems associated with recovering very 'coarse' free gold, say greater than Imm, is rare on most gold mines that have grinding and cyanide leaching circuits. For these operations it is common practice to have a gravity circuit situated within the milling circuit to recover 'coarse' free gold. Should the 'coarse' free gold constitute 15% to 20% of the total gold in a deposit then its recovery by gravity separation is seri­ously considered. As a gold mine 'matures' the availability of soft oxide ore decreases and the likelihood that harder ore having sulphide gold association increases. To maintain gold production rates in this situation either the gold grade of the treated ore must increase or more ore needs to be treated. In the latter case this is achieved by installing more grinding capacity, an expensive option, or coarsing the grind, with the downside of loss in gold recovery. In general the less expensive capital options is fol­lowed. There is, however, some upside to improve recovery when reasonable quantities of sulphide containing gold are pre­sented that can be recovered by flotation or gravity separation. Concentrates produced from these unit operations can be finely ground and reintroduced to the cyanide leach circuit to improve gold recovery. This scenario is a much less costly option than one where all the ore is ground finer. In this paper the experiences of recovering gravity gold from the Telfer Gold Mine, and gold associated pyrite from the New Celebration Mine will be discussed.

Jan 1, 1996

By W. Zhang

"Western China has many shallow coal seams. Mining of these shallow seams contributes to environmental deterioration in part due to disruption of groundwater sources. The lowering of the phreatic surface is attributed to the instability of the impermeable rock groups as a result of mining leading to an increase in permeability and drop in phreatic surface. Underground mining with partial backfilling is one of the fundamental methods of controlling the lowering of the water table in sensitive cases. At present, although significant research has been done in shallow seam mining, there has been no research on the laws governing the movement of impermeable rock groups in partial backfill mining using backfill materials of lower strength. this research, conducted in the Yu Shen-fu region of Western China, developed similar material of sand-based paste filling materials, tested the mechanical parameters of similar material of sand-based paste filling materials, researched on long wall partial backfill mining through similar simulation experiments, obtained the development of “upward fractures” and “downward fracture” under different gap-filling widths and body-filling widths and the movement law of impermeable rock groups under different gap-filling widths and body-filling widths. INTRODUCTION Jurassic coalfield is in the North of Shaanxi province in China, located in border areas of the Maowusu Desert and the Loess Plateau, water resources of Jurassic coalfield in the North of Shaanxi province is meager, ecological environment is fragile (Wang, 2010). With the large-scale development of the mining area, permeable fracture zone will directly affect and spread to the aquifer, causing direct damage to water sources, and lead to the dried up of reservoir, river, wellspring which is recharged by the aquifer(Qian, 2003). There are many researches on aquiclude or impermeable rock groups of shallow coal seam in china, but researches are mainly based on the key strata theory characterized by hard rock as skeleton, without considering the flexibility of impermeable rock groups which is important to reduce the cost of control (Huang, 2010). There are some researches on the stability of impermeable rock groups, but the researches are mainly on permeable fracture zone, which is also called the ""upward crack"" (Wang, 2010), ignoring the influence of the ""downward crack"" on the edge of subsidence basin of impermeable rock groups (Huang, 2010). Previous researches showed that pillar-and-room mining can control the rock crack and surface subsidence (Qiu, 2013), but with the loss of coal resources, and existing disaster a threat of a large scale roof falling. Partial backfill mining mainly by eolian sand bring hope to water-preserved-mining (Fan, 2000), successful practice of paste material backfill mining under buildings and water(Song, 2010)showed its feasibility. Through useing the filling materials with low strength, flexibility and small ratio of height to width, eliminated the threat of a large scale of roof falling, the quantity of partial backfill materials relative to full backfilling are little, the price of sand paste backfilling material is low(Huang, 2011), through designing rational parameters of partial backfill mining, we can achieve the purpose of protecting the phreatic. In this paper, based on the similar simulation experiments, researched on development of the ""upward crack"" , ""downward crack"" and subsidence of impermeable rock groups, researching results can provides the rational parameters to partial backfill mining, and can reduce the cost of filling mining."

Jan 1, 2015

By Y. C. Kim, W. L. Meyer, W. Cai

Although the first published optimum pit limit design algorithm by Lerchs-Grossmann dates back to 1965, the majority of the open-pit mines in the US has not as yet adopted such a rigorous optimization algorithm. Instead, the floating cone approach initially developed by Kennecott Copper in 1961 is still used today for various reasons. However, shortcomings with the floating cone algorithm, particularly for precious metal deposits with erratic mineral distributions, have provided a renewed interest in optimizing algorithms. This paper compares the performance of the floating cone algorithm with the rigorous optimization algorithm of the Lerchs-Grossman&apos;s graph theory and the newly developed maximum network flow algorithm by Hanson (1986). The maximum flow algorithm is a modified version of the logic as initially advocated by Johnson in 1968. Comparisons are made for three different deposits in terms of the total profits generated and the computation times involved. The results of the comparison show that both algorithms produced higher total profitability pits than the floating cone in all three deposits, although the increase in profits never exceeded 1 % of the base design obtained using the floating cone. Between the graph theory and maximum flow, graph theory produced consistently higher profits. The current version of maximum flow, however, cannot be modified to produce the optimum pit. Nevertheless, the authors prefer the maximum flow over the graph theory, simply because it is easy to program as well as to explain.

Jan 1, 1987

By Ted T. Biddle

The world energy crisis has created a greatly expanded exploration program for energy fuels. The demand for materials required for drilling operations such as barite, which is the primary component of drilling fluids, has increased proportionally. As in the case of many other minerals, existing high grade barite mines are no longer capable of producing the required tonnage. Consequently, exploration and development of lower grade ore bodies has been increased. The need to produce a high quality product at maximum recovery rates, along with the ever changing economics affecting both selling price and production costs has triggered accelerated research programs toward more sophisticated and efficient beneficiation methods. Taking into account the specific gravity differential between barite (4.5) and the normal gangue minerals such as silica and calcite (2.7), gravity concentration methods are the prime consideration with flotation as a scavenging process. Greater emphasis on particle size liberation, size reduction and concentration is also indicated. In order to accomplish these objectives, it has been necessary to revert back to the old adage, "Recover your minerals as soon as they are free."

Jan 1, 1980

By Jim Huerta

Diesel fuel usage in the mining industry continues to escalate. This is because approximately 60 percent of all mined materials are surface extracted by large equipment using diesel fuel, which continues to increase in cost per gallon. For example, coal mining uses large equipment such as wheel loaders, wheel dozers, draglines and [ ] dredgers. In one year, three of the largest U.S. coal mining operations consumed approximately 567 million to 852 million L (150 million to 225 million gal) of diesel. At an approximate cost average of $3.25/gal the expenditure on diesel is $487 million to $731 million per year. So, are there any solutions that could reduce this cost burden? Yes, there are. Coal mining companies can extract less ore; use more efficient extracting equipment that consumes less fuel; wait for a significant reduction in the cost of fuel; or find and use technology that would create efficiencies that would lower the cost. Nanotechnology is one such technology that might provide the means to create the efficiencies that will significantly lower diesel fuel costs.

Jan 1, 2011

By M. Scherbakov, W. Shi

Abrasion is an important mode of performance for any element of an engineered product that involves material contact for example, a conveyor belt cover. Abrasion resistance is considered to be one of the leading factors in belt cover design and improvement. Various types of abrasion testing are reviewed by and compared to actual belt applications. A new quantitative screening torsional abrasion test is developed by Goodyear to mimic a dynamic contact between belt cover and differently shaped stones of various weights dropped onto belt at any angle, velocity and height.

Jan 1, 2004

By Peter D. Warwick

Recent investigations conducted by Federal, State, and industry organizations suggest that significant coalbed gas resources may exist in the Cretaceous and Paleocene-Eocene coal beds of the Gulf of Mexico Coastal Plain. Exploration efforts have focused on three areas which are in south Texas, north-central Louisiana, and south-central Mississippi (Figure 1). Coal-bed gas production is currently underway in south Texas and in north-central Louisiana. In Mississippi, several test wells have been drilled but no data are available on their production potential.

Jan 1, 2005

By P. A. Plunkert, D. E. Morse, L. McCartan, S. F. Sibley

Following the recession of 2001, restrained consumer spending, declines in domestic manufacturing and industrial output, and increased unemployment led to a lack-luster year in the domestic economy. In 2002, the U.S. real gross domestic product (GPD) grew only 2.4%. Significant production declines in the U.S. metals industry were registered by copper, lead and zinc producers. Steel producers, despite a slight improvement in shipments, continued to face strong foreign competition, higher energy costs and lower prices for their products. Homebuilding and other domestic construction sectors— major consumers of nonmetallic mineral products such as cement, brick, glass and stone — remained strong enough to help raise the output of industrial mineral materials slightly above 2001 levels. A strong U.S. dollar relative to other national currencies continued to weaken the competitive stance of U.S. metal and non-metal mineral materials companies alike against foreign producers in markets at home and abroad.

Jan 1, 2003