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By R. E. Nelson

The Alton Coal project, located in south-central Utah, lies at one point just over six miles from Bryce Canyon National Park. This region of the southwestern United States has been called the "Golden Circle" of national parks and monuments. Can a mine be inserted into this region so that it does not intrude on this spectacular landscape? The Alton Coal Project is a proposed surface coal mine designed to serve as the fuel source for the Harry Allen Power Plant, a 1,000 megawatt generating station planned for a site 25 miles northeast of Las Vegas, Nevada. The mine and the power plant will be connected by an underground pipeline through which coal will be transported in slurry form.

Jan 1, 1988

By L. H. McGuire

Many coal beds in the State of Washington, pitching as much as 90°, offer unusual mining conditions. This paper describes methods and safe practices of mechanized mining in pitching bituminous-coal beds that have attracted the attention of mining people from most of the coal-producing countries of the world. The development and use of continuous miners as part of the mechanized program apply particularly to the Roslyn-Cle Elum coalfield, Kittitas County, Wash. All three mines now operating in the field use continuous miners and during 1957 furnished 72 percent of the State's total coal production. Mining operations are now conducted in three coal beds of the Roslyn-Cle Elum field. The coal measures range from 3-1/2 to 20 feet in thickness and vary in dip from 5° to 45° in the localities where the coal is mined. Some safety measures adopted by-the principal operating company in the field during the past 30 years of mechanized mining follow: Use of only permissible electrical or compressed-air-operated equipment on other than intake air; providing and using an explosion gallery to test repaired permissible electrical equipment before taking it underground; use of only compressed-air-operated drill augers in preference to permissible

Jan 1, 1959

By C. Roos, K. Jetmore

Developing a strategic underground mine plan is challenging and investigating multiple scenarios may take weeks. This process can be sped up using the Theory of Constraints to isolate the bottleneck mining activity and simplify the mine schedule process. This paper presents a technique to apply the Theory of Constraints to test multiple cutoff grade scenarios in Mineable Shape Optimiser and quickly produce many high-level production-based schedules that can be easily interpreted using stope-by-stope graphs, the Hill of Value, and through incremental return analysis.

Mar 2, 2022

By P SSrkkS

Mining is commonly seen as a typical basic industry with rough and even dangerous working conditions, heavy environmental load, and a low level of high-technology and automation with much manual work and operations. A mining operation (open pit or underground) is a very complex one consisting of many manual, physical, mechanical and logistical operations with different human interfaces and decisions. For this reason it is a demanding and potential area for all applications of automation and information technology: controlling difficult non-linear, time varying multivariable processes and machines; solving of ergonomic safety and environmental problems; automation of logistical systems; applying robotics, mechatronics, and information handling, etc. In addition to that, big economic sums are involved with these operations. On the other hand, automation technology has developed towards intelligent and adaptive systems including some from the above mentioned fields of automation. Connecting them with modern information and communication technologies makes the idea of an intelligent and unmanned mine more and more feasible in the near future. This requires intensive co-operation and co-ordination between the mining industry and manufacturers of mining machinery. This has been successfully accomplished in the five-year Intelligent Mine research and development program as well as the three years of subsequent implementation of its results in Finland. The basic elements of an Intelligent MineTM concept are:mine-wide information and data acquisition system; high-speed two-directional mine-wide communication network for real-time monitoring and control; computerised information management, mine planning, control and maintenance systems; automated and tele-operated machinery and equipment which are connected to the information system; and links to the public information networks. The degree of automation of an intelligent mine depends on many technical and economical factors. The basic precondition for such an approach is that it will improve the total economy of the mine. This paper will describe the Intelligent Mine Technology Program with the results. Also the implementation which took place during starting of a new underground mine (Outokumpu Chrome Oy Kemi Mine) will be described.

Jan 1, 2000

By A L. Hemphill

Conventional models, based on pulp kinetics, were regressed directly to steady-state data from a nine-stage platinum flotation plant, to provide a basis for optimisation studies. æFroth factorsÆ were used to characterise the froth in each stage and a ædepressant factorÆ was used for gangue minerals, to account for addition of depressant to the cleaners. These factors improved the fit, but differences between plant and model of up to 50 per cent were still present in a number of streams in the cleaning circuit. A new model was developed, which incorporated two rate constants for the recycle of particles from the froth. These parameters provided a workable approximation of the distribution of probabilities of particles being recycled in plant cells, depending upon where particles appeared at the surface. The feed streams were characterised by two pulp kinetic parameters and the above recycle parameters, for all minerals and all stages. The fit to the data was improved very significantly, when compared to the use of conventional pulp-based models with several pulp rate parameters. This relatively simple model did not require additional data from batch tests and it was suitable for plant simulations.Simulations of various strategies for plant operation were tested, allowing the simulator to vary the concentrate flows from all or some of the stages, in order to maximise platinum recovery. The simulator was imbedded in an automatic optimiser and constraints on chrome content or mass flow of final concentrate were used. The simulations of the existing circuits demonstrated that an improvement in recovery, (for a constant concentrate mass) of about 0.5 per cent was possible, by optimising all concentrate flows. A significant reduction in the flow of scavenger concentrate and an increase in the recycle flows in the cleaners were noted. The results of simulations of various changes to the circuit configuration are also discussed. An increase in recovery of 1.4 per cent (for constant concentrate mass) has been achieved in recent simulations, through circuit changes. However, it was necessary to keep the mass pull of concentrate, per unit area, within typical limits.

Jan 1, 2005

By Charles J. Zablocki, Robert J. Kamilli

"Abstract - Buried, possibly mineralized granite cupolas at the Silsilah tin deposit in Saudi Arabia (lat. 26°06' N, long. 42°40' E) have been successfully located using a closely spaced electric-field-ratio profiling technique. In this study, electrical fields at 27 and 270 Hz across grounded electrodes spaced 50 m apart were measured along six traverses. This method is interpretable by inspection, unlike the dipole-dipole technique, which requires mathematical modeling for interpretation.In the study area, the technique allowed the authors to identify and distinguish among unroofed granite cupolas, cupolas with their aplite-pegmatite apical contact zones intact, strong (quartz-rich) and weak (relatively quartz-poor) greisens, dikes, faults, and pervasively argillized rocks.This method should be useful in the valuation of other shallow mineral prospects in similar settings in other parts of the world, especially deposits for which the location of vertical contrasts is important, such as veins or mineralized zones associated with the apexes of small igneous cupolas."

Jan 1, 1993

By T Perera, B Fan, S Thang, T Hsia

The mining industry is currently focusing to develop and adopt sustainable collector chemistry that can efficiently recover valuable minerals from their natural state. However, a limited number of research can be seen on the design and synthesis of polymeric flotation collectors. The focal objective of this research is to synthesise a more effective polymeric collector with advanced architecture to utilise in the mineral processing industry. Reversible Addition-Fragmentation Chain Transfer (RAFT) co-polymers with cardanol derivatives have the potential to selectively trap valuable metals in the flotation process in a more efficient way. Cardanol exhibits amenability to chemical modification for making tailor-made monomers that can further produce polymers with high value. The synthesis of a series of fit for purpose copolymers in this study was accomplished by RAFT polymerisation. The ability to design complex architecture is a significant advantage in engineering polymeric collectors by RAFT polymerisation. Initially, commercially available cardanol was converted to a cardanol based monomer and copolymerised with commercially available monomers to synthesise a series of novel cardanol based copolymers with predetermined molecular weights. The side groups of the copolymer were chemically modified to incorporate functionality that can be selectively adsorbed on the chalcopyrite surface.

Aug 24, 2022

By W. E. Dennis, M. M. Fine

"INTRODUCTION During peacetime, the United States uses less than 3,000 tons of chemical-grade celestite annually. The war need, however, was estimated to exceed 15,000 tons a year.Hitherto; most of the required chemical-grade ore has been imported from England, Mexico, and other foreign countries. If foreign sources do not find it possible to meet the demand for ore of chemical grade (plus 92 percent SrSO4), it is expected that requirements could be satisfied by concentrating low-grade domestic ores. Celestite deposits on Brown, Nolan, Fisher, and Coke Counties, Texas, are considered to be possible sources of supply for this low-grade material. The Bureau of Mines explored the most important deposits to determine the grade and amount of ore available and conducted ore-dressing tests to obtain a suitable method of concentration.The exploratory work, consisting of test pitting and sampling, was carried on under the direction of W. E. Dennis, one of the authors of this paper, from October 8, 1942, to January 30, 1943. The ore dressing-tests described herein were conducted at the Bureau of Mines Laboratory at Rolla Mo.In this report, a particular deposit is referred to by the name of the landowner on whose .property the .deposit lies. The location of the deposits investigated is shown on figures 1, 2, 3, and 4.The celestite deposits were previously studied by the Bureau of Economic Geology of the University of Texas, and the results of its investigation are published in Mineral Survey Circular No. 46."

Feb 1, 1947

By R. B. Nourse

The depressed market for Ferrochrome worldwide has forced most producers in this industry to scale down production. Inevitably, many furnaces have been mothballed for prolonged periods, awaiting an upturn in the Ferrochrome market. In contrast, the Platinum industry is experiencing relative stability combined with good prices and they have been looking for cash cows to take advantage of these market conditions. It is, therefore, rather convenient that Platinum and Ferrochrome producers are virtually neighbours in the Bushveld complex of South Afiica, since there is an abundance of spare furnace capacity around (albeit for Ferrochrome). Against this backdrop, Pyromet Technologies (Pty) Ltd, who are currently designing a slag cleaning furnace for Anglo Platinum, was requested to perform pilot scale testwork on a 200kW furnace, in order to establish the suitability to process platinum concentrate and converter slag in a furnace designed for Ferrochrome. This paper provides an overview of the configuration, test conditions, operation and results achieved during the testwork. It also discusses the critical issues, such as refractory consumption, copper cooling and electrical parameters that need to be addressed when converting a Ferrochrome Smelter into a Sulphide Smelter.

Jan 1, 2002

By David J. Krichten

A method of retrofitting air-fuel burners with oxy-fuel capability overcomes the potential problems associated with oxygen combustion in aluminum melting furnaces. The retrofit burner uses the existing combustion air connection, burner housing, and burner tile and replaces the gas tube with an oxy-gas burner. Maintaining a portion of the air flow to the burner reduces the potential for localized overheating. Proper design of the burner reduces NOx emissions by moderating the flame temperature with furnace gas recirculation. Economic analysis of using oxygen shows the benefits are increased productivity and reduced overall unit cost of melting. In practice, the melt rate in rotary furnaces increases by up to 50% and by up to 35% in reverberatory furnaces. Oxygen utilization reduces total melting cost by 112-314 cents per pound of aluminum melted.

Jan 1, 1997

By A. H. Onur

Spontaneous combustion of coal is a significant hazard in underground coal mines. It causes serious problems for miners for many years after the fact. It threatens workers? lives and causes economic losses for companies. It disrupts coal production and makes it necessary to abandon the main drift where the spontaneous combustion occurred. Coal fires have to be prevented before they occur; otherwise they are very hard to control. Precautions thus have to be taken in potentially risky areas. For coal to spontaneously combust, it needs 3 elements: fuel, oxygen and heat. If one of them is missing, the fire cannot occur. The best way to prevent spontaneous combustion is to prevent contact between coal and air. Coating of the coal surface with an air-proof lining material would be a practical and useful solution to prevent spontaneous combustion of coal. In the scope of this study, a lining material for coating the coal surface was designed at laboratory conditions. Lining material to be used for preventing coal fires should be airproof, cheap, sufficiently strong, have low rebound, be water- and heat-resistant, and easily obtained and applied. It should also be safe for human health when in contact with mine ventilation. By considering these obligations, 3 kinds of gypsum (plaster, satin plaster, molding plaster), as well as lime, cement and fly ash and different mixtures of these materials were applied in laboratory conditions to form a lining material. Samples of lining material were subjected to uniaxial compressive strength tests to determine their behavior against roof loads. Although there is no need to carry any roof load, the lining material has to be sufficiently strong to stay in place on the applied surface. If the lining material is broken, coal and oxygen can react again. Air permeability and curing time of the mixtures were also tested in laboratory conditions. Then the tested mixtures were applied on a wall with a pump to test the applicability of mixtures. After all tests were performed in laboratory, the most suitable mixture was determined as the optimal lining material to prevent coal fires.

Aug 1, 2013

By R. L. Russell

Production at Freeport Indonesia's Ertsberg open pit copper/gold mine started in 1972 at a rate of 7500 t/d. Mill throughput remained at that rate for a number of years until the discovery of the Ertsberg East (GBT) orebody. This discovery prompted three successive expansion stages from 1981 to 1988 that boosted production to 20,000 t/d. The discovery of the huge Grasberg porphyry copper deposit in 1988 launched a new era of much larger expansions. The first of these involved installation of a fourth primary mill in 1989 to bring production up to 32,000 t/d and was immediately followed by an expansion of the crushing and screening plant and the addition of a new south concentrator to bring production to 57,000 t/d in 1991. The addition of a primary ball mill and the changeout of the original Denver flotation cells in 1993 has served to optimize current production at a level of 66,000 t/d. A major expansion is now in progress. This includes construction of another new concentrator to house a SAG mill circuit and large Wemco flotation cells in an area created by the removal of 6,000,000t of glacial material. This current expansion, with a planned completion in 1995, will take production to 115,000 t/d. This paper describes the evolution of the Freeport Indonesia (FI) concentrator to-date and will then go into an in-depth discussion of the 66,000 and 115,000 t/d expansions.

Jan 1, 1994

By K. B. Le Bron, T. van Aard

The empirical pillar strength formulae have been widely, and in most cases successfully, applied to design underground pillars for mines in the Bushveld Igneous Complex (BIC). This paper presents the case for combining the empirical method with numerical modelling when it comes to crush pillar stability analyses. The benefits include an understanding of potential failure mechanisms, which may then be accounted for in the designs. In addition, the impact of weak layers, such as shear zones, the impact of the dip of the orebody, differences in layouts, such as holing widths and the presence of advanced strike gulleys (ASGs) immediately adjacent to the crush pillars, and stress regime (k-ratio) may be studied using numerical modelling, as it is not accounted for in the empirical method.

Mar 5, 2025

By M. Pelser, H. Gous, J. H. W. M. Brits, K. Voogt

The effect of impurities; iron and selenium, on current efficiency and deposit quality in copper electrowinning was investigated using an at-line cell at the Rustenburg Base Metals Refiners’ Copper Tankhouse. The tankhouse is a direct leach, starter sheet electrowinning operation with a unique electrolyte composition. The effect of iron on the current efficiency in the at-line cell was found to be less severe than reported in literature. However, the distinction between the chemical impact of iron on current efficiency and the physical impact of iron on a starter sheet operation needs to be realised. The effect of selenium on current efficiency and deposit quality is also reported. INTRODUCTION Anglo American Platinum’s Rustenburg Base Metals Refiners’ (RBMR) Copper Tankhouse serves a unique function in the refinery flowsheet in that its primary functions are the removal of copper and production of acid for the leach circuit. This function needs to be performed to specification in order to keep the leach circuit operating optimally. Current efficiency is seen as an indicator of tankhouse performance and efficient energy use. The tankhouse plates starter sheets onto titanium blanks which, after stripping and preparation, return into the production cells for further plating. Approximately 78% of tankhouses surveyed (Robinson et al., 2013) use permanent cathode technology whereas older, smaller operations still use starter sheet technology. Drawbacks of the starter sheet technology are that the starters are thin and bend easily leading to increased shorts, they need to be removed after two days of plating to be manually straightened and are then returned to the cells. In addition, the electrolyte levels in the cells need to be adjusted during the plating cycle to improve loop adhesion to the cathode and reduce loop corrosion. The starter sheet technology is therefore very labour intensive and the final quality of the product is dependent on the quality of the starter sheets produced. In comparison, permanent cathode or direct plating technology lends itself to automation, allows for higher current densities and better cathode quality due to more robust geometric stability in the cell. The present barrier to implementation of permanent cathode plating at the RBMR Copper Tankhouse is the capital cost required to convert the tankhouse, i.e. blanks and stripping machine. At present, alternatives to titanium blanks, such as LDX 2101, are being investigated for the unique electrolyte composition of this tankhouse.

Jan 1, 2019

By Philip A. Bucci

The Florida phosphate industry successfully uses froth flotation to concentrate phosphate in: the particle size range of approximately 28 to 150 mesh. However, as recently as 1965, coarse particles in the range of 14 to 28 mesh generally had not been beneficiated by conventional flotation methods at recoveries high enough to be considered adequate. It has been customary to upgrade this coarse material; by "agglomerate flotation" or "skin flotation" using belts, tables or spirals. While these devices have proved commercially effective, their capacities are much lower than those of froth flotation cells. To determine whether coarse phosphate material could be recovered successfully by froth flotation, Armour Agricultural Chemical Company began a series of pilot and plant tests; in April 1965. Objective of the tests was to compare over-all performance of a froth flotation cell design relatively new to the phosphate industry with results from the belt circuit at the Bartow, Fla., plant.

Jan 1, 1966

By C. W. EICHRODT

NUMEROUS requests for the suspension of publicity make difficult the preparation of the annual review of copper metallurgy for 1934. In the United States, sales allocations indirectly have set restrictions on the scope of activities of producers and refiners, and necessitated closer cooperation between secondary and primary producers. However, the feeling exists that preparations for a return of intense competition should not he neglected, and careful investigations are being conducted for ways and means of improving industrial positions and production methods. In all probability, efficiency in technique and equipment will prove of far greater importance in the near future than production capacity, and many important developments in copper metallurgy later will be found to have been born during the current year.

Jan 1, 1935

By Jerry C. Tien

China?s remarkable levels of economic growth during the past three decades have lifted almost 300 million people out of poverty. This amazing achievement has placed an increasing demand on energy and minerals, especially coal, which supplies 68.7 percent of China?s energy (June 2011). It is estimated that China mined more than 3 Gt (3.3 billion st) of coal in 2010, three times as much when compared to merely 10 years earlier. Such an impressive achievement does not come without major costs ?? including concerns with mine safety and an increasing number of occupational illnesses due to fast growth. This article reports on one of the major safety concerns in China?s coal mining, dust and dust control practices, and known cases of caol worker?s pneumoconiosis affiliated with prolonged exposure to excessive coal dusts. The exact size of China?s mining industry is not known, but it is estimated the coal industry is at least five-million people strong, and the metal and nonmetals industry probably employs another three million people. To meet increasing energy demand, China mined more than 3.1 Gt (3.4 billion st) of coal in 2010 from its 15,000 plus coal operations1, most of which are small- to medium-sized operations with annual coal productions ranging from a few thousand tons to 300 kt (330,000 st). These small coal operations are typically in remote areas, inadequately engineered, poorly ventilated and still using rudimentary drilling and blasting mining methods employing antiquated mining equipment and, presenting safety concerns, i.e., methane and dust explosions.

Jan 1, 2011

By K. Huessener

This paper attempts a survey of the principles involved in the combustion of blast-furnace gas in boilers and stoves. I do not expect to be able to give much information which is actually new, since the laws and methods of calculation pertaining to this problem are contained in a number of handbooks; but, so far as I am aware, they have nowhere been treated exclusively with reference to this one problem of gas economy. The road which I follow is less that of strictly scientific research than that of the practical engineer, faced by operation problems which require a quick solution by easily accessible means without a prolonged search in scientific handbooks. For this purpose I give a number of tables and diagrams, as well as the results of many years1 practical working experience as combustion engineer, which I trust will prove useful to my readers. HlSTORICAL Considering the tremendous efforts made during the last 15 years to increase the efficiency of all kinds of power plants, it is highly surprising that until a comparatively very recent period, progress in the economical combustion of blast-furnace gas has been so slow, The explanation generally put forth, that fuel has been so cheap that it was hardly worth while to bother about this economy, will not hold good, for the greatest trouble was taken to improve the combustion of coal and to reduce the consumption of steam, The most plausible explanation appears to be the general impression, held as an accepted fact, that gas, especially hot, uncleaned, blast-furnace gas, was not a good boiler fuel. Many managers of high repute had tried unsuccessfully to improve the conditions of its use, and the dictum went forth that efficiencies of over 60 per cent., particularly with high loads, were impossible. This was the situation not only in the United States, with very cheap fuel, but also in Europe, where fuel prices are twice and three times as high.

Jan 1, 1916

By Francis Chachula, Niel Erasmus

"In 2002, Titanium Corporation Inc. focused its attention on the development of a process for the recovery of valuable heavy minerals, including zircon and titanium bearing minerals from oil sands froth treatment tailings. The development of a process flowsheet to recover the titanium and zircon minerals from the Athabasca oil sand tailings has evolved through many laboratory, bench and pilot scale iterations.Initial development work focused on so-called ‘beach sand’ material, which is tailings material deposited over a period of time close to the tailings pipe discharge. The derived process flowsheet primarily consisted of gravity concentration stages, which is typical of all mineral sands operations. Titanium Corporation’s business plan calls for the utilization of tailings directly from the tailings pipeline – the process developed around the beach material is therefore risky as it differs from the live tailings in a number of aspects, with the effects on the process unknown. Titanium Corporation successfully obtained an intermediate product through a ‘bulk sampling plant’ coupled directly to an Oil Sands operator’s froth treatment tailings pipeline, during the summer of 2005. Subsequent further processing of this material resulted in poor separation or concentration of the heavy minerals due to a number of reasons. A more effective process flowsheet had to be developed.The newly derived process is basically a marriage between mineral sands technology and oil sands technology that can economically concentrate and recover the heavy minerals and entails the incorporation of a flotation process that takes advantage of the entrained bitumen in the feed to separate the heavy mineral fraction from the quartz gangue This paper will describe the newly derived process as well as the successful results of a subsequent on-site concentrator pilot campaign completed during the 3rd Quarter of 2006."

Jan 1, 2008

By W M. Tekano, T S. Coulter, N M. Hutt

The Vancouver Island Highway Project (VIHP) was a $CAD 1.2 billion expenditure by the Province of British Columbia to improve travel safety and relieve traffic congestion between Victoria and Campbell River on Vancouver Island. In the section of highway between the Tsolum River and Oyster River, on the Inland Island Highway portion of the VIHP, over half of the rock to be cut and filled was found to be net acid generating. The Tsolum River has been impacted by metal leaching and acid rock drainage (ML/ARD) for decades from an upstream closed minesite. Geochemical testwork indicated: over half of the rock along this section of highway was potentially net acid generating based on a site-specific SNPR (=NP/SAP) criterion of 1.5; some core samples were already acidic; pyrite occurred in disseminated framboidal and gel forms; the rate of acid generation was not high; measured neutralisation potential (NP) provided some lag time for the onset of net acidity; and non-carbonate neutralising minerals prevented low pH (These predictions led to ML/ARD controls involving: realignment of the highway; elevation control to minimise the volume of disturbed rock; encapsulation of blasted-rock fills within the highway, surrounded by low-permeability till and covered with asphalt; and diversion of water away from cut faces. Internal pipes drained any water reaching the fills into external ditches and ponds, where the water could be monitored and, if necessary, treated. Water from the cuts was also captured in ditches and carried to monitored ponds. Elevated aqueous sulfate concentrations in several ponds confirmed that sulfide minerals were oxidising, but the lack of both acidic pH and increasing trends in concentrations demonstrated that ML/ARD was controlled. Contingency plans for any pond that may become acidic include water treatment, which predictive testwork has shown would not require substantial amounts of limestone or lime.

Jan 1, 2003