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By Allan R. Ide

It is a great pleasure for me to speak-before such a prestigious group as the American Institute of Mining, Metallurgical and Petroleum Engineers. The substance of my talk today is the handling of coal and petroleum coke: their characteristics and environmental problems, and how we were able to correct the problems, prescribe the cure and enjoy the benefits. When coke first became a by-product derived from the oil refineries everyone would have been very happy if someone had offered to take this pro- duct off their hands. Unfortunately, there was no market at that time, and no one seemed interested. Soon thereafter, it became a sellable product and began to be shipped to many countries in the world. This was when all of the pollution problems began. I will be talking briefly about some of these problems and showing a short film on this subject afterwards.

Jan 1, 1984

By J. A. Jirestig

Laboratory investigations on the possibility for magnetic separation of sulphide minerals are reported. A survey of several sulphide ores and flotation concentrates shows that magnetic separation in most cases is not a suitable primary method of beneficiation. However encouraging results have been obtained in concentrate purification. At the Boliden complex sulphide ore concentrator in Garpenberg a Allis-SALA MK III carousel High Gradient Magnetic Separator (HGMS) is used together with a small flotation circuit to recover sphalerite lost to the galena concentrate in lead flotation. The result after four years of refining the HGMS process, show increasing zinc recovery and enhanced quality of the lead concentrate.

Jan 1, 1993

By R. Pixler

Arch Mineral Corporation and Rocky Mountain Energy's Medicine Bow Mine in Wyoming presented an interesting challenge to the concept of mining a multiple-seam, dipping coal in the Hanna Basin. The 3362 and 2962 pits at MBCC were designed in a multiple seam coal consisting of 4 (and in some areas 5) bands of coal; these coal beds are all in the Ferris formation. The area was subject to some localized faulting and a major fault caused a physical restraint that we mined up against in our final cut. Using a 1570 dragline as the principal stripping machine, the concept of developing a bench for stripping the lower seams from the low-wall side of the pit was initiated. The results of this method of stripping were very satisfying for this pit through the completion of pit life and prompted us to use it in other areas at MBCC and at our other operations. Mining a dipping coal presents a small twist to conventional "flat" coal stripping. The spoil has a tendency to continually try to slide into the pit and the increased overburden on each cut as you mine down the dip creates spoil problems unless adequate design provisions are made prior to stripping.

Jan 1, 1986

By Douglas Ball

An underground storage field is a gas field where man, not nature, has put all or most of the gas. All but one of those in use today are in the pore spaces or "porosity" of sedimentary rocks, the most common being sandstone. The one exception, near Newcastle, England, is a gas storage in a cavern dissolved from rock salt. The tens of millions of barrels of LPG (liguified petroleum gas) now stored in salt caverns mined in shale is liquid storage, not gas storage, and in this paper I recognize the presence of these installations but do not include them in the gas storage category, Since, with the English exception, gas storages are gas fields, they can all be sorted into the categories used to describe gas fields, 95% of them once gas fields anyway, but some of the remaining 5% are the ones having the greatest effects on underground waters.

Jan 1, 1960

By Peter B. Knuckey

1, Introduction Location Kalengwa mine is located in the North Western Province of Zambia, 402 kilometre by unpaved road to the west of Kitwe, which is roughly in the centre of the Zambian Copperbelt, well known as one of the world's centres of copper mining. Its position is illustrated on the map of Africa in Figure 1 and on the map of Zambia in Figure 2. It is a mine of Roan Consolidated Mines Limited whose other properties, Mufulira, Luanshya, Chambishi and Chibuluma Mines, are all located on the Copperbelt. It is managed by the Chibuluma Division of the company. The rate of production from Kalengwa will vary from 12 000 to 17 000 tonnes of saleable copper a year over the next six years. Kalengwa did not exist as a place until the first prospecting parties and later the mine became established and the early working population was recruited entirely from small villages in the surrounding area as much as thirty miles away. The mining area consists of fourteen mining locations amounting to 3.35 square kilometres and the land may be used for any purpose connected with mining, including housing, wood cutting and other utilities. The whole area is, except for minor undulations, a fairly flat plateau with main rivers running from north to south and flood basins known as "dambos" located in a general east west direction. Vegetation is, with the exception of the grassy dambos, temperate forest with relatively light undergrowth. Game of great variety is prolific, as is the associated tsetse fly.

Jan 1, 1971

By John M. Moore

Within the Pofadder district of Namaqualand, South Africa, economically exploited deposits of bedded barite and zinc-lead-silver-copper sulfides occur in close proximity within highly metamorphosed mid-Proterozoic pre-tectonic para¬gneisses of the Namaqualand Metamorphic Complex (NMC) (figure i). The paragneisses belong to the Bushmanland Group (SACS, 1980) that comprises a relatively straight-forward regional sequence of basal leucogneisses, intermediate mica-sillimanite schists and glassy quartzites, and a mixed upper zone of banded iron formations (BIF), minor marbles, quartz muscovite schists and localised uppermost quartz-pebble conglomerates and amygdaloidal mafic gneisses (Joubert, 1974) (figure ii). The base metal and barite mineralisation occurs in close association with BIFs, generally above the glassy quartzites, although in some cases possibly below them. In the regional context, the Bushmanland Group paragneisses are, to the north, intercalated with and ultimately replaced by meta-volcanic sequences of talc-alkaline affinity (Reid, 1977) belonging to the Orange River Group (SACS, 1980). The metavolcanics are generally of acidic to intermediate composition and show evidence of subaerial formation from 'high altitude shield volcanism' with many acidic ashflow and welded tuff bands, mesocratic and lesser melanocratic lavas and some fanglomerates (Ritter, 1980). To the south and east, the schist/quartzite associations are initially intercalated with and eventually replaced by cordierite gneiss/metacarbonate/biotite gneiss associations of shallow marine affinity (Moore, 1980a). The Bushmanland Group paragneisses appear to represent sedimentary material in the extreme distal portions of a talc-alkaline volcanic environment adjacent to a shallow platform sea.

Jan 1, 1983

By Michael Lenz

Predictive maintenance technologies including vibration analysis, tribology, infrared thermography, ultrasonic detection, and electrical measurements have been applied to large electric mining shovels. The predictive program was initiated on the P&H Model 2300 and 4100 electric shovels. The utilization of these technologies has shown the potential for improving electric mining shovel availability and minimizing maintenance costs. Predictive technologies provide the tools to assess machinery condition. Availability is enhanced by the condition based planning of component replacement. Maintenance costs are minimized by focusing resources through condition based prioritization.

Jan 1, 1997

By A. Noble

"Linear circuit analysis (LCA) is a fundamental tool that may be used to evaluate, design and improve the performance of mineral separation. The traditional LCA methodology provides a comparative evaluation of circuit designs purely from the unit interconnections. The quantitative approach uses the analytical circuit solution to evaluate the slope of the circuit’s partition curve at the midpoint. Since the partition slope is often associated with a separation’s general selectivity, this numeric value is used to compare and rank alternative configurations. Unfortunately, the partition curve slope only reflects the separation potential of middling material. By itself, this value does not account for the relatively high unit dollar value of pure material or the gains and losses in mass yield associated with alternative circuit configurations. Realizing the value in the LCA methodology, but respecting the limitations of the partition slope valuation, the authors have derived two new performance indicators that quantitatively address pure particle misplacement (the Partition Moment of Inertia) and circuit mass yield (the Yield Score). Together, these parameters provide a better indication of separation economics in typical mineral and coal separation systems. Since the two parameters provide independent information on circuit selectivity and circuit yield, a Pareto efficiency, multi-objective function selection approach is proposed for preliminary circuit selection.IntroductionOver the past 30 years, numerous scientific and industrial studies have proposed various mineral processing circuit design methodologies that attempt to optimize the allocation of separation resources within the processing plant. Over this period, the methodologies have undergone various transitions, including the increased inclusion of process models and computationally intensive algorithms, as well as a general shift from a purely technical solution (Lauder and McKee, 1986) to partially economic solutions (Abu-Ali and Sabour, 2003; Cisternas et al., 2014). Today, circuit design is largely driven by flowsheet simulation; however, no consistent design methodology is used across the industry.One intriguing approach for circuit evaluation is linear circuit analysis (Meloy, 1983a). This method evaluates the separation potential of the circuit solely considering the unit configuration and stream interconnections. No preliminary data other than the basic circuit configuration is required to use the approach."

Jan 1, 2015

By J. Marsden

Lift height, overall heap height and climate all play an important role in determining precious metals leaching rates, recoveries, operating costs and capital cost requirements for heap leaching operations. The effects of these factors are not easy to predict from testwork, and this can result in unexpected delays in metal production, lower recoveries than expected and higher capital and operating costs than necessary. This paper investigates the economic impact of lift height, overall heap height and climate on heap leaching and provides criteria to assist in the design and operation of leaching facilities. Descriptions of three heap leach operations in the western USA are provided to support the discussions and conclusions.

Jan 1, 1995

By M. J. Raffaldi, K. W. Harris, K. A. Perry

"Highwall miners have been widely used to extract additional coal reserves from existing surface operations, particularly on contour operations in the Appalachian coalfields. Using a continuous miner cutting head, coal may be extracted from significant depths (such as 150 m), leaving behind an array of web and barrier pillars with the purpose of maintaining highwall stability. This method inherently involves elevated risks to both equipment and personnel due to proximity to and increased exposure time near highwalls. As a result, modern operations should actively design web and barrier pillars to maximize extraction while providing adequate stability. The ARMPS-HWM software, an empirical-based program created for the design of web and barrier pillars at highwall mining operations, is one such approach. The calculated stability factor is compared with empirically established guidelines produced from examining case histories.The ARMPS-HWM program is a handy tool for initial design, but understanding the site’s structurally significant geologic features and geomechanical behavior is important and may potentially increase extraction. We created a two-dimensional numerical model using FLAC3D and calibrated it to ensure pillar strength, closely following the Mark- Bieniawski formula for a typical range of pillar geometries and overburden properties. The development of pillar stresses along a highwall panel was then numerically investigated as mining progressed, and the stress distribution between barrier pillars was found to be asymmetric, which can result in an over-design of the closeout web pillars if tributary area loading is assumed. Finally, the importance of adequate barrier pillar stability is highlighted."

Jan 1, 2014

By R. DasGupta

The dissolution behavior of gold in ammoniacal solutions at 75°C has been investigated. The variables investigated include concentration of lixiviants, pH of the solution and various oxidants. The anodic dissolution of gold was studied in the absence of oxidants using the potentiodynamic polarization technique. The cathodic reaction of oxidants was studied on a platinum electrode. Tafel polarization tests were also performed to determine the dissolution rate. The overall dissolution of gold in ammoniacal solutions was examined using a mixed potential theory. A comparative study on the role of cupric am mine, oxygen, hydrogen peroxide, sodium hypochlorite as oxidants for the dissolution of gold in ammoniacal solutions has been carried out.

Jan 1, 1996

By K. A. Foo

Minproc Resources Inc. is developing a tailings retreatment project in Bolivia at the Colquiri zinc-tin-silver mine, in the Bolivian Andes. Mining at Colquiri has been continuous since 1940 and COMIBOL, the Bolivian state mining company, has owned and operated the underground mine since 1964. There are 10 million tonnes of tailings at Colquiri containing 0.51% Sn, 4.21% Zn and 50 g/t Ag. Minproc plans to mine and concentrate the tailings at 1.15 million tonnes per year to produce feed for pyrometallurgical upgrading. The tailings are moderately complex, with cassiterite grain size ranging from 200 to 5 pm. The marmatite (ZnFeS) in the tailings is relatively easily recovered, with zinc recovery of 80% to a 40%-45% Zn concentrate. The major problem with the zinc metallurgy is that the marmatite is complexed with iron, which results in iron contents of 14%-17% Fe in concentrate. This makes the product very difficult to sell because of the low Zn:Fe ratio. Most zinc smelters require a Zn:Fe ratio of 6:1 or 7:1, whereas this concentrate has a 3:1 ratio. Concentrate sale terms are therefore unfavorable, and the high cost of transportation from Bolivia to the smelters is an additional burden.

Jan 1, 1992

By Edward P. Larsen

At our annual meeting in St, Louis, Mo. in February 1961, we presented a comprehensive paper (No. 61-B-22) on the subject of "Blending and Handling of Materials for Agglomeration". In that paper you will find a discussion on the difference between "blending" and "mixing". With regard to "blending" we brought out the facts of its usefulness for the preparation o materials in an agglomerated mass to attain controlled chemical and physical uniformity. "Mixing" was discredited as not being useful for the attainment of uniformity of any kind.

Jan 1, 1962

By H. J. van Antwerpen

AngloGold Ashanti operates the world`s deepest mine, Mponeng gold mine, in South Africa. A vast refrigeration and ventilation system provides acceptable working conditions 3800m below surface at 60°C rock temperature. In such a system, optimisation and assessment of modifications becomes very difficult. With that in mind, a research project was launched to determine whether recently developed system simulation technology can be applied to a mine as vast and complex as Mponeng. Using the techniques and methods as implemented in FLOWNEX software, it was indeed proven to be possible to do a mine-wide combined simulation of compressed air flow, ventilation air psychrometry and refrigeration water systems. Interactions between the various streams included heat transfer, pressure drop, evaporation and condensation. The simulation model was used in a parametric study to test various water flow and temperature operating points for the refrigeration system. It was found that, given current limitations, the mine refrigeration system is running fairly close to optimal but with some opportunities for improvement. The simulation model also provided useful insight for future changes or extensions to the system.

Feb 23, 2014

By E. B. Kroeger

Spoil instability has been a problem at a coal mine in interior Alaska. Parameters such as original site topography, groundwater conditions, material properties, spoil-pile geometry, geology, permafrost, natural slope instability, changing weather conditions, and dense, near-surface vegetation have interacted to produce unstable slopes. Several failure modes have been identified including deep seated earth block slides, bimodal earth flows, and solifluction. Thawing of permafrost also created conditions where sliding of spoil along the interface separating the spoil and the natural ground surface occurred when the cohesion and the friction angle of that zone was reduced to zero and below 15?respectively.

Jan 1, 1992

By Robert D. Brown

The purpose of this paper is to tell a story - and it is a story with a moral. My topic is Present Trends in the Tax Environment Affecting Mineral Development in Canada, and the first thing to recognize is that, with depressed metal prices and weakening western economies, taxes, in and of themselves, are not really the cause of the Canadian mining industry's present doldrums. But the character and level of mining taxes in Canada has had a profound influence on the development of the industry over the past decade, and the expectations of what taxes the industry will face in future years will influence the industry's further growth. My theme today is that, in Canada, our tax system has, in the past, served as a negative and destabilizing influence in the mining industry: it has contributed to a major short-fall in investment commitments and hence in the contribution which the mining industry can make to the Canadian economy, and the adverse effect on the industry of previous high tax rates was made far worse by the confusing, contradictory and perverse nature of the tax system itself. This is a story with some happy parts in it, and, in fact, governments in Canada did learn, haltingly and grudgingly, that there are limits on the amounts that governments could safely extract from the industry, and that some assurances of long term fiscal stability were necessary if investors were to be induced to make massive commitments which could only be recovered over very lengthy periods.

Jan 1, 1982

By R. J. Visintainer, J. M. Furlan

"Due to the time-consuming nature of froth testing in a laboratory environment, practical limitations require the development of a method of applying a single set of performance test data (Visintainer and Whitlock, 2012) obtained for a single froth pump at a given speed to a range of froth pump speeds and sizes, % air content and liquid viscosities. Head, efficiency and flow all vary as functions of both liquid viscosity and air content. As such, it is necessary to develop a technique that can be used to interpolate from existing test data in order to predict froth performance for pumps of various sizes running at variable speeds. Details of the technique developed in order to achieve this goal, as well as the insights gained from analysis of the resulting regressions, are discussed. Additionally, comparisons are made between the performance predictions of this test-derived method and those of the Hydraulic Institute standard for the effects of liquid viscosity on centrifugal pump performance (ANSI, 2010).IntroductionPump performance data (Visintainer and Whitlock, 2012) has been collected for a froth pump using an experimental loop outfitted with an array of pressure transducers, mass flow meters, an inverted U-loop, magnetic flow meter and an assortment of other instrumentation. Experiments were performed on pure water, water and air, pure corn syrup, and corn syrup and air. Data was obtained for % air contents of 0-30% and viscosities of 1- 15,000 cSt at eight specific valve positions (eight different flows as a percentage of best efficiency flow points) and the viscosity was changed by allowing the system temperature to increase during testing. The test pump is a 710-mm diameter impeller, GIW HVF, open shrouded, vented design that has its discharge axis oriented at 45° upward from the horizontal. A schematic diagram of the froth pump test loop can be seen in Fig. 1."

Jan 1, 2015

By J. S. Rapp

This report is based on existing reports and recently gathered field data. It discusses mineral resource potential of Tertiary playas in the Fort Irwin region. An estimated 1.3 million tons of measured salt "reserves", and 20 million tons of indicated salt resources, have been identified north of the fort. Other indicated resources include 300,000 tons of celestite, 800,000 tons of gypsum, and 10 million tons of selenite. Zeolitic tuff was mined south of Fort Irwin from 1978 to 1984, and unexplored occurrences are widespread. Calcium-bentonite is mined near Barstow, and more may exist, including valuable sodium-and lithium-based bentonites.

Jan 1, 1992

By Reul A. Dejú

The mineral olivine has been the subject of continued research by various authors. Paik (1967) conducted infrared and flotation studies of the adsorption of sodium alkyl benzene sulfonates on olivine. These studies are of interest from two points of view. First, in the metallurgical field it is of interest to understand the mechanism of silicate flotation using sulfonate collectors and second to a hydrologist studying the pollution of surface or subsurface waters it is of interest to study the reactions taking place when water plus sulfonates encounter a porous (silicate) medium. On the basis of Paik's study he was able to postulate a possible mechanism for the attachment of RSO3 (sulfonate radical) to the olivine surface. Parks (1969) has been studying the important influence of the structure of a silicate such as olivine on its dissolution mechanism and its related surface charge. Also Luce, a student of Parks (1964, 1965) has been studying the kinetics of dissolution of olivine using the techniques of direct solution analysis and infrared analysis. Certainly a classic in the study of silicate dissolution is the work of Murata (1940) on the reaction of orthosilicates (olivine in particular) with strong acid solutions. Many authors (Dejú and Bhappu, 1966. 1967. 1968, Dejú, 1969; Rhoades and Krueger. 1968, and Faust and blunter, 1967) have reported studies of the behavior of silicates immersed in water (especially orthosilicates) and have found that there is an exchange of cations from the silicate surface for H+ from the water. Studies by Dejú and Bhappu have also included the system olivine-water-amine.

Jan 1, 1971

By David W. Houston

The increasing energy crisis, coupled with stringent environ- mental regulations, has created new demands for high capacity materials handling systems with unit train transporting and continuing surveillance of quality control. Effective and efficient methods of material conveyance are through high speed, high volume conveyor belts with the monitoring of quality through the utilization of automatic sampling. When we speak of high speed, high volume belt discharges we are referring to speed ranges from 600 to 750 FPM and volumes as high as 5500 TPH. To achieve the optimum operating sampling system for high capacity belt discharges, it is imperative that two major design characteristics be investigated and evaluated; namely technical analysis of operating conditions through application of ASTM design criteria and practical experience in the selection of equipment and the design of related components. The task of obtaining a sample of reasonable weight to represent an entire lot presents a number of problems and emphasizes the necessity for using standard sampling procedures.

Jan 1, 1973