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By David A. Campbell

There has been a long history of ironmaking on the North East coast of England centered around the River Tees. The industry developed here because of the availability of good coking coals to the North in Co. Durham, and the discovery in 1851 of ironstone in the nearby Cleveland Hills, South of the .River. Cleveland ironstone is relatively poor in quality, with an iron content not exceeding h% and high proportion of sulphur and phosphorous. The iron exists in chemical association with alumina and silica, and physical beneficiation processes involve a serious loss in iron unless the upgrading is limited, when the economics of the process become doubtful. Over the years, richer foreign ores have replaced the local ironstone, and the last operating mine was closed in 1964.

Jan 1, 1982

By Nath S. Parate

With the extension of mining beneath residential and industrial areas, it is becoming increasingly necessary to extract coal and minerals in such a way that subsidence damage due to groundmovement is reduced to a minimum. Understanding clearly of the mechanism of subsidence development is a must in view of the environmental problems and the energy crisis today. This paper gives a simple analysis of various components resulting from subsidence and the influence of other factors on their development. An up-to-date review of the subsidence and strain profiles is presented, with particular references to the coal mining operations. The importance of this topic from mining damage to structures, buildings properties and environment in mining areas is undeniable. Field results are discussed.

Jan 1, 1982

By Samuel S. Adams

The Grants uranium region of northwest New Mexico is the largest uranium district in the United States (approximately 50% of U.S. production plus reserves) and one of the largest In the world, with approximately 900 million pounds U308 production plus reserves. Deposits of the region are unusual among sandstone deposits for their high content of epigenetic carbonaceous material, generally interpreted but not proved to be of humic origin--that is, co-extensive with uranium in the primary deposits. Virtually all production in the region has been from the Jackpile Sandstone and Westwater Canyon Member of the Jurassic Morrison Formation. The tabular uranium deposits contain, in addition to humate and uranium, significant authigenic phyllosilicates, quartz overgrowths, humate-replaced detrital silicates, and a trace-metal assemblage typical of other sandstone uranium deposit types. Surrounding the deposits in the two sandstone units of the Morrison Formation is an alteration zone within which iron leaching has altered detrital ilmenite-magnetite to residual masses of titanium oxides. Feldspar alteration is locally present within this zone, below deposits in the Jackpile Sandstone, and above those in the Westwater Canyon Member. The feldspar alteration increases in inten¬sity toward the Brushy Basin Member which separates the two sandstone units, ranging from partial replacement to replacement and dissolution of plagioclase and sanidine. Spatial relations among the epigenetic humate, authigenic silicates, and the broad alteration zones that extend from the Brushy Basin Member to and including the uranium deposits suggest that (a) the organic material was involved in the unusual silicate alteration, transport, and authigenesis, and (b) that the humates originated in shales of the Brushy Basin Member. Stratigraphic relations among the Brushy Basin Member and the overlying Jackpile Sandstone and underlying Westwater Canyon Member suggest [in turn] that there was continuous, interfingering deposition controlled in part by contemporaneous basement subsidence along northwest- and northeast-trending zones. Following minor erosion of upper Jackpile Sandstone and deposition of basal organic-rich Cretaceous sediments, the silicates of the Jackpile Sandstone were once again altered by organic-bearing fluids, this time permeating down from Cretaceous sediments and partly obliterated ore-stage alteration.

Jan 1, 2013

By W. T. Walter

High-G centrifuges from five preparation plants were sampled to determine and quantify the various operating factors affecting performance. The operating factors that were considered include feed rate and percent solids, size of feed material, screen-basket type, hardness of coal and age of the flights. The performance parameters that were measured include product surface moisture, recovery and degradation of the coal. Regression equations with good significance levels were developed.

Jan 1, 1982

By Jr. Abel

Subsidence is controlled by a complex combination of mining and geologic factors. For example, a world-wide compilation of data shows that, as the percentage of shale in the overying rock mass decreases and the amount of sandstone increases, the angle of draw (and the area affected by subsidence) decreases. Limestone in the overburden appears to cause as much as a three-fold decrease in the angle of draw compared to a like amount of sandstone. Increased amounts of sandstone were accompanied by a greater surface subsidence relative to the mining height. The total thickness of overburden did not appear to influence the subsidence magnitude above super-critical panels. The greater the thickness extracted the smaller percentage of that thickness that shows up at the surface as subsidence. The greater the percent of the seam extracted, the greater the subsidence reaching the surface. The maximum subsidence above room and pillar panels is dependent on the pillar height and minimum width as well as the other factors listed.

Jan 1, 1980

By R. L. Bleifuss

The object of this study was to evaluate the oxidized taconites of the western Mesabi iron range and to establish a correlation between the various basic taconite types and their concentratability. This study was made at the Mines Experiment Station of the University of Minnesota under the sponsorship of the Great Northern Railway Company. The initial work included a study of the original mineralogical and stratigraphic facies of the fresh taconite and traced the oxidation and leaching patterns developed during the conversion of this material to oxidized taconite. Subsequent studies have extended this work to include the semi- taconites and also the wash and heavy media ore types widely developed in the area. Each basic, original mineralogical facies or taconite type produces during alteration an equivalent secondary oxidized facies which has a unique mineralogical composition and texture. These control the concentratability of the oxidized taconites. Actually the influence of the original mineralogical composition of the iron formation extends even further and determines whether the most likely product of oxidation and leaching will be a wash ore or a heavy media ore and even to the direct shipping ores where the ratio of hematite to goethite is largely determined by the original taconite type.

Jan 1, 1964

By A. Vaillant

Classifiers that are used to separate granular materials into a coarse and a fine stream, are considered. Fundamental Equations are presented which apply to all, such Classifiers and all feed size distributions. The practical, real Classifier is compared quantitatively with the perfect. Classifier. A Formula is introduced for the Real Classifier Selectivity, that defines what portion of each particle size is sent to the coarse outlet duct. This selectivity function is characterized by three Parameters, one of which (b) is a numerical measure of the sharpness of classification. A new dimensionless variable (J) appears in Equations and Graphs for recirculating load, product size distribution and specific surface in the classified product. This variable combines the effects of sharpness of separation, Classifier setting and fineness of a Rosin-Rammler Type feed to the Classifier. Classifier efficiency is defined, based on Specific Surface.

Jan 1, 1967

By Edwarde R. May

The Flambeau volcanogenic massive sulfide deposit located in northwestern Wisconsin occurs within the southern lobe of the Canadian Precambrian Shield. The steeply dipping tabular body occurs in a complex pile of cyclic schistose intermediate to felsic fragmental volcanics. No chloritic alteration pipe is recognized but adjacent rocks have undergone magnesia metasomatism and subsequently were metamorphosed to the upper greenschist and lower amphibolite facies. Although modest in size the deposit is of special interest in that it has an extensive and well preserved supergene enrichment blanket. Economic minerals found within a pyritized quartz-sericite schist are chalcocite and bornite overlying primary chalcopyrite.

Jan 1, 1976

By G. Barbery

A review is given of the present applications of random sets and integral geometry in fragmentation and liberation models of ores and minerals. Although attempts have ben made in the past to apply such mathematical techniques to the comminution of solids, it is shown that it would not result in major progress. In liberation modelling, it is demonstrated that the approach can lead to fruitful results. Following a recent paper by Davy (1984), a model of liberation prediction is developped, which can be calibrated far ore texture and breakage using image analyzers. The model is demonstrated for the case of a Poisson polyhedra ore texture and monodisperse fragment size. The model enables to predict the complete composite particle distribution, and is thus valuable for integration of ore breakage models with minerals separation models.

Jan 1, 1985

By James F. Lemons

The potential production of cobalt from nickel sulfide deposits in Canada, from nickel laterite deposits in the Pacific Islands, and from the copper deposits of Zaire and Zambia will be a function of the cost of recovery of the primary nickel and copper products. This cost of production varies significantly for these deposits and is related to the differences in the cost of labor, energy, and supplies, to production technology, and to the grade and recovery of nickel, copper, and cobalt. This Bureau of Mines paper investigates these cost and technology differences as they relate to the cost competitiveness of the deposits in Canada, Zambia, Zaire, and the Pacific Islands.

Jan 1, 1984

By Harold L. Lovell

The current interest in sulfur recovery from coal measures is indicated by a recent report prepared for the Public Health Service (1) It was noted that the concentration of pyrites to a product containing 42-48 percent sulfur should be relatively easy with present equipment. It was also pointed out that a utility potential exists for the high-grade iron concentrate which results as a by-product of the consumption of pyrites in the acid-making process. However, economics, marketing characteristics, location, transportation, pyrite levels and coal characteristics all strongly influence the feasibility of fostering industrial development of such processes. The extent of pyrite recovery and product quality is intimately related to pyrite particle size and its degree of liberation, a consideration usually given greater emphasis in metal ore preparation than in processing coals. Consequently, fine crushing to nearly 20 mesh probably will be essential for maximum practical processing. It appears that any process separating pyrites from a coal must involve a reprocessing of the normal preparation plant refuse, although some yields can be attained from certain existing operations as products from, a shaking table or a jig. Further, the existence of millions of tons of coal refuse cannot be ignored as a mined source of raw materials. The recovery of saleable products from such wastes, although untried on a large scale under current conditions, not only offers a realistic source of sulfur but also would achieve a secondary refuse with the minimal contents of substances which incite and propagate the burning of organic and inorganic combustibles. These silicate materials, thus beneficiated, also offer some potential for economic utilization. Some significant tonnages of pyrites have been produced from coal measures in the past, but the experience was, in general, not consistent with current coal preparation practice. The processes involved did not include cyclones and heavy media; nor were they carries out under the sociological environment concerned with pollution as exists today.

Jan 1, 1967

By J. S. Aronofsky

The areas are identified where the techniques of operations research have been applied in the petroleum industry. Particular emphasis is given to the linear program models that have been used for solving management problems. Of the entire gamut of applications for linear programming, attention is focused on the models that represent underground reservoirs. Such models could be used to help schedule drilling rig operations and to schedule oil production. A framework is established for placing the model for underground reservoirs in the proper perspective along with the models which represent other facets of the oil business. One of the remarkable phenomena of this century is the rapid growth in the size and' complexity of human organizations. The mere size of modern business means that administrative decisions can affect vast quantities of capital and large number of people. Mistakes can be tremendously costly, and a single wrong decision can require years for rectification. Moreover, the pace of modern business is such that decisions are required more rapidly than ever before; the mere postponement of action can give a decided advantage to a competitor. It is not surprising that the increase in difficulty of decision making has been followed by efforts to put this activity on a more objective basis. The growing science of operations research, which relies heavily on the methods that have proved so successful in the physical sciences, is one aspect of these efforts.

Jan 1, 1962

By James M. King

Analytical models for transient groundwater phenomena, such as those of Theis, Cooper, and Jacob, are important but often limited tools for aquifer evaluation and drawdown prediction. Most were developed using simplifying assumptions which compromise their treatment of complex boundaries and most also contain functions that are mathematically complex and difficult to solve explicitly. Examples of such functions are the Bessel functions, the exponential integral, and similar well functions for leaky confined and water table aquifers. This paper describes the joint use of simple numerical techniques and numerical approximations of these functions to extend many analytical models beyond their conventional applications. The enhanced analytical methods represent many hydrologic problems more easily and realistically, permit a wider range of application, and often provide insight into the response of pumped groundwater systems without the need to resort to more complex numerical flow models. Use of the enhanced analytical methods usually requires the use of microcomputers due to the large number of computations. Examples presented here are the development and extension of type curves and the determination of drawdown distributions.

Jan 1, 1984

By R. Venkataramani

Even though the mining industry in 1966 produced more ore than ever before, current extraction rates are only a fraction of what is expected in the later years of the twentieth century. Nearly 90% of all metals and-mineral products consumed last year was recovered by open-pit mining. This has placed great pressure on this segment of the industry which has, consequently, resulted in some spectacular developments. With increasing size of projects, the need for increased sophistication of engineering, planning, management and administration of modern mining installations has never become more apparent. The design of complete systems for the mine and plant that fit the mould of today's business and social environments is undergoing an evolutionary process. Traditional concepts in mine development and operations are being sidestepped in favor of new ideas and principles. As the overburden thickness increases, materials handling presents a major problem to mining companies, especially those concerned with the mass production of ore and waste from low-grade deposits. The profit margin here is likely to be significantly less as to take chances with capital investment. 1 Constant efforts are needed to improve upon productivity if the ore is to be economically mined.

Jan 1, 1970

By G. C. Hambleton

There is sufficient indication of the existence of a basic misconception in the Coal Mining industry (on a world-wide basis) as to what computer control really does, what it costs, how it works and how and what it achieves as to make this presentation a welcome opportunity to present the case in what we hope is a simple, meaningful way. A plant cannot be said to be "automated" unless the control system has the capability to react automatically in accordance with predetermined programs under a great multiplicity of operational situations.

Jan 1, 1981

By Ronald G. Schmidt

AND SOME RIN UP HILL AND DOWN DALE, KNAPPING THE CHUCKY STANES TO PIECES WI' HAMMERS, LIKE SAE MANY ROAD MAKERS RUN DAFT. THEY SAY IT IS TO SEE HOW THE WARLD WAS MADE. Sir Walter Scott St. Ronan's Well - 1824 In the minds of many, geologic exploration has advanced little since the early nineteenth century. In truth, despite the development and refinement of new and potentially valuable technological tools, the approach or philosophy of the explorationist has received meager attention in professional literature. In many areas, the explorationist relies upon experience, subjective judgement and general intangible inspiration, often traveling together under the misleading pseudonym of "art," in achieving both an exploration plan and in making the myriad day to day decisions necessary to the execution of that plan. Without a solid, objective basis for decisions, exploration under this concept is little more than guesswork largely by intuition, and it is small wonder that many exploration programs flounder in a sea of over-expenditure inefficiency or fail to fulfill their expected goals within the funding which has been provided. From a rational management point of view, such a state of affairs is frustrating and inconsistent with the application of the same scientific principles which are presumed to be the basis for the exploration methods which are used. This somewhat presumptuous point of view cannot be extended as a general condemnation of the many exploration programs which are both technically and economically successful. On the other hand, the

Jan 1, 1968

By Levent Ozdemir, Charles Merguerian

Between 1996 and 1999, a high-performance Robbins TBM [235-282] excavated a 5 mile long, 23´2? wide, and ~700´ deep tunnel through the subsurface of southwestern Queens. Low penetration rates (~6´/hr [actual] vs. ~9´/hr [anticipated])resulted from changed rock mass conditions mostly attributable to high-grade metamorphism of the rocks. Over a three-year period, as-built circumferential geologic mapping (scale 1?=10´) and digital imagery of the tunnel, fracture and fault analysis, structural, lithologic, and petrographic studies have shown that the rocks of the Queens Tunnel consist of orthogneiss of mesocratic, leucocratic, and mafic composition. These metaigneous rocks developed coarse-grained fabrics during Grenvillian (~1.0 Ga) granulite facies metamorphism, and retained their nearly anhydrous, poorly foliated character during subsequent high-grade Ordoviciande formation. Lacking a penetrative foliation, the coarse granoblastic rock texture and extraordinary garnet content (up to 50% in some zones) together proved animpediment to efficient chip production and resulted in bimodal production of blocks and excessive fines. TBM excavation of the Queens Tunnel was also hindered by geological conditions that included unexpected lithology and rock fabric orientation, a zone of crosscutting hypabyssal rhyodacite dikes, and unanticipated extent of brittle faults. The dikes and brittle faults produced blocky ground conditions and a collapsing face condition that produced cutter damage and decreased utilization. Such fundamental textural, mineralogic, and lithologic control over hard-rock TBM penetration can be predicted by careful pre-bid geological analysis. To determine the causes of lower than anticipated TBM performance, a detailed investigation was carried out that included analysis of operational data from the TBM data logger and an extensive laboratory test program on cores retrieved from tunnel walls. Integrated laboratory testing included punch, point load, tensile strength, Cerchar abrasivity, and linear cutting tests, independent petrographic analysis and machine performance analysis. These allied investigations have provided quantification that the rock mass exhibited an unusually high degree of toughness and rock directional properties and established geological causes for decreased TBM penetration rates.

Jan 1, 2003

By Roger N. Kust

Because ammonia can form complex ions with certain of the transition metals, such as copper and nickel, it has long been of interest to extractive metallurgists interested in leaching or separating these metals. Although it is a relatively expensive reagent, ammonia is amenable to recycle because of its volatility. In development of processes utilizing ammoniacal leaching or separation schemes, information regarding solution vapor pressures, pH and solubility limitations is needed. There is voluminous literature on ammonia-water systems generated by the urea industry. However, frequently the systems of interest to metallurgists differ significantly in concentrations of ammonia used, the temperatures of interest. Furthermore, the differences arising from the presence of metal values in solution must be comprehended. There is surprisingly little information readily available regarding systems of practical interest to metallurgy. As a result, those interested in ammonia-based processes end up either doing expensive laboratory research to obtain necessary data or overdesigning the process. Another approach to obtaining desired information about ammoniacal systems is to attempt to calculate from first principles the various solution properties. This paper is being presented to illustrate what can be accomplished by estimating the state of equilibrium in an ammoniacal carbonate system from available thermodynamic information making simplifying assumptions when needed.

Jan 1, 1976

By J. C. Draper

The Duquesne Light Company and GAI Consultants, Inc. conducted a demonstration program aimed at establishing permanent vegetative cover directly on acidic, deep coal mine refuse. Several plots were treated with formulas varying in soil amendment application rates and plant species. Periodic monitoring of refuse chemistry has indicated when maintenance applications of seed and soil amendments were required. To establish drainage control, the site had to be regraded. The most successful formula was applied to the entire site. Specific treatment for acidic spots has been initiated. Results of the program indicate that adequate permanent vegetation has been established.

Jan 1, 1983

By D. R. Gladwell

This study examined the-feasibility of clay mineral identification and quantification by reflectance radiometry and subsequently developed a computer algorithm for deconvolution of the component spectra. Clay mineral analysis of 53 rocks and soils from Alberta, Saskatchewan, Ontario and Nevada by X-ray diffraction (XRD) compare favourably with the radiometric determinations. The application of the technique to precious metal exploration was examined at the Horse Canyon epithermal gold deposit, Cortez Mine, Nevada where low levels of illite and kaolinite are present alongside local silicification. Consequent on the success of the laboratory and field work a field portable clay mineral analysis system was designed and constructed.

Jan 1, 1985