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By Marcelo B. Mourao

Interactions of carbonaceous materials with liquid Fe-C melts have been investigated experimentally by determining the volatile yield due to rapid devolatilization (Flash Pyrolysis) and rates of dissolution at temperatures ranging from 1623 to 1873 K. The volatile yield increased with increasing the temperature. The comparison of results of different types of carbonaceous materials was possible by expressing the volatile yield in terms of Enhancement Factor, fE. The rates of dissolution of spectroscopic graphite and an industrial coke seemed to obey the correlation for natural convection under turbulent conditions. The experimental data for the graphite suggested that the rate of dissolution was controlled by the mass-transfer in the liquid boundary layer adjacent to the solid sample. The value for the empirical parameter correlating the dissolution coefficient and the operating variables was found to be 0.19 which was close to that reported in the literature. The comparison of the results obtained for the coke samples with those for the graphite revealed that the impurities and the porosity of the samples can effect the dissolution rates.

Jan 1, 1992

By Gerald K. Vellente

Producers of strip coated products are being approached by users to supply higher quality products and adhere to tighter specifications. Suppliers, in an attempt to assist the producers, must consider new technologies for equipment. In the past several years, the induction melting and heating industry has made great strides in developing new and innovative equipment, while improving existing technology. In the past several years, the induction melting and heating industry has made great strides in developing new and innovative equipment, while improving existing technology. In the past several years, the induction melting and heating industry has made great strides in developing new and innovative equipment, while improving existing technology. This paper will review recent developments to include improved refractory systems for ceramic pots, new channel-type inductors which are more efficient, new power control systems for existing channel-type pots, and innovative use of multi-purpose lines. Additionally, new heating applications such as galvannealing, edge heating, and post heating will be reviewed. Advanced math models for controlling heat will be discussed. Producers can easily meet the demands of their customers because of the flexibility provided by the equipment reviewed.

Jan 1, 1992

A Good Product Range - So What! While in terms of water, waste management and environment protectrion, the Gippsland Basin may appear to have a good product range, what does this really mean? What it means is that, like any product range, the virtues of the product range must be sold and accepted by a majority of the public. The social, economic and environmental benefits of any enterprise using these products must be sold and accepted by the regional population. Many a budding entrepreneur has failed because he assumed that the public would accept his product, so good did it appear to be! However, we know that such an assumption must be avoided and that a great deal of time and effort needs to be invested in promoting and gaining acceptance of a product to ensure a long term and viable market.

Jan 1, 1992

Over the years, numerous studies have been conducted to characterize the floatability of coal pyrite. Unfortunately, many of the results obtained using isolated samples of coal pyrite are not directly applicable to actual coal flotation systems where liberation and entrainment may be the major factors affecting pyrite rejection. In this paper, the association of pyrite with other coal constituents is investigated, and the data are presented for feed and product streams obtained from release analysis tests. Release analysis is used to minimize the effects of entrainment. Particle distributions for each stream are presented as functions of size and composition in order to discern the behavior of free and composite particles.

Jan 1, 1992

There remains considerable controversy in the industry regarding precision type detonators and where the end user can benefit from their use. In spite of the fact that electronic detonators and other prototypes were tested over one decade ago, explosive suppliers have hedged on full scale production for many reasons. Although some of the reasons were based on solid economics, others were strongly influenced by shear internal resistance within the corporate objectives, ultimate fear of market rejection, indecision as to what degree of precision was required and limited data on defining the real benefits to the end user.

Jan 1, 1992

By G. R. Doubek

Dual Tube Reverse Circulation (DTRC) drilling has been extensively used for collecting groundwater information for the dewatering program at Amax Gold Inc. Sleeper Mine. This paper presents a discuss ion of the types of data which can be collected from DTRC drilling, as well as the effect submergence has on the data. A simple low-cost method of injection testing has been developed using DTRC equipment, allowing quantitative data to be obtained from exploration or test holes. Potential yields can be determined for each drill location, allowing siting and design of production wells to be optimized.

Jan 1, 1992

By M. Gangal, M. Grenier, D. Mchaina, S. Hardcastle

"Exposure to airborne respirable silica in surface and underground mine operations is known to be the cause of industrial lung diseases. For this reason, silica is a regulated substance and worker exposure must be monitored regularly. Diesel exhaust also contains substances which are potential caricinogens. In an underground setting, diesel particulate may be the main component of what is referred to as respirable combustible dust (ReD). Although diesel particulate or soot is not at present a rigorously regulated substance, new epidemiological data is prompting North American institutes and agencies to regulate diesel soot or RCD exposure. This paper describes a method where by silicaand RCD exposure may be determined using a single personal sample. In this method, an airborne respirable dust sample is obtained and analyzed nondestructively for silica components using an on-filter X-ray diffraction method. Filters are then ashed at 500°C in a muffle furnace over a four-hour period to determine mass loss due to RCD burning. Using on-filter X-ray diffraction analysis as opposed to redeposition of dust samples onto another analytical substrate allows the"

Jan 1, 1992

By J. Dorsey

In 1910, Colonel Boyce Thompson, who owned Inspiration (now Cyprus Miami) and various other mining interests, formed the Magma Copper Company and leased the Silver Queen claims around Superior, Arizona. At the same time, he purchased other claims around the Silver Queen claims from what was then called the Magma Mine. The mine continued to operate until 1982 when Newmont Mining Company, who owned Magma Copper Company, shut down the operations due to high costs and low copper prices. When Magma was spun off by Newmont as an independent company in 1987, new studies of Superior were started. It was clear from these studies that the mine had been shutdown and over 1400 employees laid off for two basic reasons: first, as a resu1t of a mine plan that was technically flawed and second, be-cause of very high production costs mainly due to the low productivity from a very high cost work force. During 1989 a plan was formulated to re-open Superior with the determination to over-come the problems that resulted in closure. A new mine plan was developed and a management style developed that promotes team work and high productivity.

Jan 1, 1992

By H. Lyn Bourne

This is the 10th annual tabulation of US mineral royalties published in MINING ENGINEERING. The first year, 1982, the author solicited information about royalties and the cost of reserves. That column contained only a few royalties - not enough to tabulate. Since then, the response has been sporadic but the entries have grown to more than 300. Some have been deleted. Some of the older information has been deleted to make room for new entries. All indications suggest that the readers enjoy and use the information. But more information is needed. Russian practice In 1989, this column gave a brief history of mineral leasing and royalty payments as the concept applies to mining in the United States. This year's narrative deals with information about the mineral ownership in Russia. That country is in political and economic turmoil, including administrative systems and methods. And many laws are likely to change. What follows describes the Russian system of mineral ownership as of early 1992, according to Kirill Kavun. He begins "All the subsurface space of the Russian Federation with minerals contained belongs exclusively to the state. This forms the Common State Mineral Fund. Land parcels may be state, municipal, public or private property. They may be let to be owned and used by individuals, juridical persons, national/territorial or administrative/ territorial formations." This seems to apply to surface rights, as known in the US.

Jan 1, 1992

By Wayne D. Goodfellow, William M. Luff, Steven J. Juras

Abstract-Brunswick No. 12 is a vent-proximal massive sulfide deposit that formed above a feeder pipe with associated hydrothermal alteration. Because of the replacement of bedded sulfides deposited above the hydrothermal vent, individual sulfide lenses show the following vertical and lateral zoning outward from the vent complex: massive pyrite-pyrrhotite-chalcopyrite core - interlayered pyrite-sphalerite-galena (Pb-Zn ore zone) - bedded pyrite. The feeder zone which underlies the Cu-rich core consists of an anastomosing network of pyrite-pyrrhotite-chalcopyrite­ quartz veins with variable and generally minor contents of ferroan carbonate, Fe-rich chlorite, sphalerite, galena and arsenopyrite. Hydrothermal alteration of felsic igneous rocks hosting and adjacent to the feeder pipe is represented by an inner zone (zone 1) characterized by sulfide stringers, Fe-rich chlorite, muscovite, quartz, and ferroan carbonate that formed at the expense of feldspars and what was probably glass; outer zones (Il and III) are represented by Mg-rich chlorite and muscovite formation, and the albitization and silicification of K-feldspar. Accompanying these alteration trends is a marked decrease of Na + Ca, and an increase in Fe + Mg + C03 in zone 1, and increases in Mg + Na in the outer zones. The classic zoning of metals within the sulfide lenses, the formation of a feeder pipe below the vent-proximal sulfide core, and the hydrothermal alteration of felsic volcanic rocks cut by the feeder pipe all support a vent-proximal origin for the Brunswick No. 12 deposit. Furthermore, restriction of sulfide stringer mineralization to the footwall sequence, the folding of the stringer zone by an F1 fold, and the difficulty of long distance mass transfer of metals from the sulfides into the host rocks all argue against a tectonic origin for the stringer zone. All of the evidence indicates that the feeder pipe formed during the ore forming hydrothermal event, but has been distorted and in some areas detached from the overlying massive sulfides during subsequent deformation.

Jan 1, 1992

A methodology is described to integrate heap leaching into a CIP operation. The paper firstly describes what is meant by a 'systems approach'. A broad view of the objectives of integration of heap leaching into CIP is given, followed by the components of the system, and then a description of the methodology for integration. The seven stages of integration are given as determination of distribution of gold, sampling, metallurgical testwork, conceptual study, pilot heap operation, pit modelling and pit optimisation. The final result is a series of optimised curves which determine the maximum value of the orebody, and the optimum cut-over grade from CIP to heap leaching.

Jan 1, 1992

By G. M. L. Robinson

The Clean Water Act, as administered by the Environmental Protection Agency, has mandated industry, government and the public to comply with potentially conflicting and vague water quality statutes, regulations and guidelines. Universal regulatory strategies have been developed which have introduced and have created regulatory, compliance and institutional conflicts. Conflicts have been created because National water quality performance goals and design standards are vague, and, in many cases, cannot be scientifically justified. Because of regulatory technical requirements to define background and environmentally impacted water quality characteristics, the ability to achieve regulatory compliance is difficult. Difficult issues requiring resolutions includes but are not limited to site specific surface and ground water quality classification systems, water quality standards and guidelines, point and non point pollution sources etc. Because of these statutory and regulatory complexities, a confrontational regulatory system has been created as it relates to: - defining performance criteria in relation to design criteria; - resolving water quality statistical compliance conflicts; - defining laboratory precision requirements; - determining background groundwater characteristics; and - locating a representative point of compliance. Because of these complex regulatory issues, the ability to balance goals, needs and economics has not been achieved or in many cases has not been attempted, without legal intervention. A few examples illustrating where water and waste management compliance conflicts have been experienced.

Jan 1, 1992

In west-central England, 183 m (600 ft) below the Cheshire Plain, lie the evaporate remains of an ancient sea. Stratified into nine beds of salt separated by marl bands, the deposit stretches roughly 21 x 12 km (13 x 7.5 miles) and contains reserves of rock salt estimated as high as 400 Gt (440 billion st). The Winsford Salt Works, one of England's largest underground mines, extracts the Cheshire salt and sells it for use as animal feed, for application in de-icing programs, and as a key ingredient in sodium fertilizer production and a variety of other industrial processes. Because road de-icing is an important market, demand for Winsford's salt varies with the severity of British winters. Design capacity is 2.25 Mt/a (2.5 million/year). However, production peaked at 2 Mt (2.2 million st) in 1987. Over the past five years, annual production has averaged 1.6 Mt (1.7 million st). Run-of-mine salt averages 92.5% NaCl, mixed with about 5% marl. The marl was formed by deposition of a reddish dust blown into the Cheshire basin from deserts in what is now central Europe. Association with the marl adds color to the salt, producing tea-colored crystals that resemble unrefined sugar. Adaptation of coal mining systems Rock salt mining in the Winsford district began at least as early as 1682. Mining at the current site dates from 1844 but was shut down from 1892 to 1928. In the early 1900s, a series of catastrophic collapses and floods plagued and ultimately shut down then-active Cheshire brine-salt producers. Subsequently, Winsford reopened and began adapting mechanized underground coal mining systems to rock salt extraction.

Jan 1, 1992

By Thomas J. Peters

In 1978, the U.S. Bureau of Mines and the U.S. Geological Survey completed a joint mineral survey of the Chemise Mountain and King Range study areas as mandated by the Federal Land Policy and Management Act of 1916, Public Law 94-579. The U.S. Bureau of Mines examined all identified mineral prospects and deposits; the results of these examinations are included in this report. The U.S. Geological Survey studied the regional geology, geochemistry, and geophysics; the results of these studies are available in USGS Map MF-1196. No mineral resources were identified in either the Chemise Mountain or King Range study areas; however, a high-grade silver and base-metal occurrence, and minor manganese resources were identified in between the two study areas, within the King Range Conservation Area. The only mining activity in either area was a placer gold prospect on Honeydew creek in the northeastern part of the King Range study area. Three samples from this prospect contained no gold. The Chemise Mountain and King Range study areas are in a mountainous region along the coast of northern California, 230 road miles north of San Francisco, and 70 miles south of Eureka by way of U.S. Highway 101, through Garberville and Redway. The Chemise Mountain study area consists of 3,941 acres; it includes the 2,598-ft Chemise Mountain, and the cliff-lined seacoast southeast of Shelter Cove. a resort and fishing village. The King Range study area consists of 39.764 acres northwest of Shelter Cove, and includes the northwest-trending King Range with elevations above 4,000 ft. The Chemise and King Range study areas are underlain by deep-water marine sandstones, shales, and minor pillow basalts of the Late Cretaceous and early Tertiary Franciscan Subduction Complex. Mineral production was 1,650 tons of manganese ore within a manganiferous bed overlying pillow basalt at the Queen Peak mine southeast of the King Range study area. However, no significant manganese resources were found in the Queen Peak area. The Point Delgada area, directly south of the King Range study area, has prospects with high grade copper, lead. silver, and zinc. Exposures are inadequate to estimate resources; however, the metals may be associated with Franciscan volcanism (volcanogenic). The Chemise and King Range study areas may contain similar economic silver-rich, base-metal deposits.

Jan 1, 1992

Mining at Hudson Bay Mining & Smelting's (H. B. M. & S.) Snow Lake Division is now in the mature stage of the mines lives. These base metal copper-zinc mines have been operating for over 30 years. Stopes had small pillars called "crown pillars", left between them. These pillars range up to 100 meters long by 40 meters wide and 15 meters thick. H. B. M. & S. has been successful in removing these pillars through the use of cable slings, electric scoops, longhole mining and diesel LHD equipment. The different shapes and sizes of these pillars has meant that many innovative techniques have been tried in order to find acceptable economic mining methods. An overview of the different methods will be outlined.

Jan 1, 1992

By Arthur W. Cooper

This paper contains a review of the development of blast furnace? slag handling and processing technology in the Ironmaking industry over the past 30 years, with an emphasis on economic and environmental factors. The requirements and practice of air-cooling slag for use as aggregate and of pelletizing and granulating slag for use in cement manufacture are described. The operation of slag pits, slag pots or ladles, the slag pelletizer and early granulation systems are compared with the new continuous .granulation, dewatering and handling systems developed in the past decade.

Jan 1, 1992

By J. Kevin Cotchen

The results of "submerged arc" electric furnace processing of a variety of materials is discussed with respect to the process and products, including the characteristics of the products (e.g. TCLP or Toxicity Characteristics Leaching Procedure). The materials melted include slags and wastes containing various metal oxides including copper, tin, lead, zinc, chrome, nickel and other associated elements. The findings of these tests are compared to those reported in the literature for other operations treating similar "wastes".

Jan 1, 1992

By Helmut Attlfellner

The selection of the best process for the oxygen generator for a metallurgical process requires the determination of all aspects which impact the economics of this facility. Concepts and features of modern air separation plants will be presented based on installed facilities for various metallurgical processes. The special features of advanced automation' of oxygen generators with load following and optimization of power consumption, automatic restart and unattended remote controlled operation will be investigated.

Jan 1, 1992

By R. W. Barbaro, R. V. Ramani, K. V. K. Prasad, P. T. Luckie

Discussion by A. Unal Barbaro et al. (1990) implemented a tedious study aimed at delineating the short-scale spatial variability of sulfur in a coal seam. It is not possible, however, to extend their conclusions to any other coal seam or use their in any other fashion, because the background geology was not presented. Nor were the conclusions accompanied by geological interpretations in the paper. In addition, an unfortunate printing error occurred where the total sulfur (determined by High Temperature Combustion) variogram in Fig.3 was duplicated in Fig. 2 instead of the seam height variogram. A more serious error, however, has been committed in the definition of the variable, seam height. What is defined as seam height by Barbaro et al. (1990) is, in essence, mining height, and is not a regionalized variable that should be studied by geostatistical methods directly. Despite the fact that the variable, seam height, is not defined in the paper explicitly, the following quotation discloses the fallacy: "All roof rock that exceeded 1.8 m (6 ft) from the floor was not taken because the longwall was operated to not mine more than 1.8 in (6 ft) unless the coal seam height exceeded 1.8 m (6 ft)." From this definition, the seam height, and therefore the sampling height, is equal to the actual coal thickness, if the coal thickness is greater than 1.8 m (6 ft). Otherwise, it is equal to the sum of the coal thickness plus the thickness of the roof rock that complements the thickness to 1.8 m (6 ft). In the latter case, the seam height is constant and equal to 1.8 m (6 ft). It is possible to conduct a variogram study on a pool of samples that are realizations of two different variables. But the conclusions derived would not belong to any one of the two variables uniquely and, therefore, do not possess any significance. Geostatistical analysis is irrelevant for the sum of multiple regionalized variables formed by arbitrary selections. In a two-seam setting, for example, the mining height, as defined by the thickness of one seam at one location and the thickness of both seams at another location (due to quality and/or minimum thickness considerations perhaps), should not be used in the calculation of one common variogram. The two seams should be modeled separately. They can then be combined according to the specific purposes of the study. On the other hand, if a constant is added to a regionalized variable (to incorporate dilution perhaps), the variogram of the new variable will not change. Barbaro et al. (1990), surprisingly, does not give any geological interpretation of their results despite the fact that most of them can be explained by the origins of sulfur in a coal seam. The presentation of the results of a geostatistical study with no reference to the geology of the deposit is uninformative. It may also be misleading for the potential users of geostatistics, It is not unusual to find nuggets of pyrite in coal seams. In such cases, pyritic sulfur will probably display a spatial structure for only a very small distance that will appear in the experimental variogram as no spatial correlation. This very well known phenomenon is called the pure nugget effect in geostatistics (Journel and Huijbregts, 1978) and perhaps can explain the lack of correlation found for pyritic sulfur content. The lack of correlation found for the total sulfur content may also be explained in the same way because the total sulfur content is dominated by the pyritic sulfur content in this case study. One should notice, however, that the situation may completely be reversed after cleaning the coal. Not all of the inorganic sulfur should be expected to be in the form of pyrite nuggets in a coal seam. It may also be disseminated in the coal seam and it is expected that it follows a certain spatial structure. However, an existing spatial structure may be masked by including a part of the roof rock, rich in sulfides, into the seam thickness in an arbitrary fashion because areas having a sandstone roof sometimes are known to show a higher sulfur content due to the downward percolation of solutions rich in iron sulfides (Clark, 1979). Plants use sulfur in their growth processes. Much of this sulfur is bound organically during peat accumulation and coal formation (Cecil et al., 1978.) This suggests a spatial structure of some sort for the organic sulfur. However, it is not possible to test this hypothesis because the results obtained by the authors for the organic sulfur content are not given in this paper. For this reason, the conclusion that simple average of the nearby samples would provide the best unbiased estimates is questionable for organic sulfur and is not based on any substantial supporting evidence. It is suspected that no spatial structure was detected and this was due to high sampling and laboratory analysis errors. Before concluding that sulfur variability in the seam at the location of study was random, a more detailed study for the disseminated non-pyritic sulfur should have been conducted, not for the sake of scientific curiosity only, but also due to its utmost importance with regard to coal cleaning and emission control. Pyritic sulfur can be cleaned to a considerable extent, whereas organic sulfur can not, making the emission control strategies highly dependent on the spatial distribution of the organic sulfur (Knudsen, 1981). In the light of these facts, one wonders why Barbaro et al. (1990) did not present the results of their study for the sulfate and organic sulfur content. References Barbaro, R.W.. et al., 1990, "Short-Scale Spatial Variability of Sulfur in a Coal Seam,' Mining Engineering, Vol. 42, No. 11, pp. 1267-1269. Cecil, C.B., et al., 1978, "Geology of Ccontaminants in coal," report prepared for Environmental Protection Agency, North Carolina, 123 pp. Clark, W.J.. 1979, "An interfluve model of the upper Freeport coal Bed in part of western Pennsylvania," unpublished MS thesis, University of South Carolina, 57 pp. Journel, A.G., and [Huijbregls], Ch. J., 1978, Mining Geostatistics, Academic Press, London, 600 pp. Knudsen, H.P., 1981. "Development of a Conditional simulation model of a coal deposit," unpublished PhD dissertation, The University of Arizona, 109 pp.

Jan 1, 1992

By L. P. Meade

The need to feed an established talc mill from a crude are source located closer to the mill prompted the drilling in 1986 of a previously mapped talc-carbonate deposit. This talc-bearing rock had never been considered as a potential source of crude talc are because of the high carbonate content and other deleterious minerals that were observed in outcrops. Selective mining, in-pit grade control and creative processing has allowed this deposit to be developed into an orebody. By definition, an orebody has to be a source of positive cash flow. With industrial minerals, this is determined as much by market acceptance as by are tenor.

Jan 1, 1992