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By K. O. Groves

Although chlorine oxidation has been found to be effective in destroying the CN ion, an excess of chlorine is needed to drive the reaction to completion. This often results in the formation of residual chloramines, which are toxic to aquatic life and often regulated by various states. The interhalogen, bromine chloride (BrCl), has been found to be just as effective but without the formation of persistent, residual chloramines. The hydrolysis and subsequent disproportionation of the highly-polar BrCl molecule essentially yields a solution of hypobromous acid (HOBr) and nonoxidizing hydrochloric acid (HC1). Studies have been carried out to directly compare the mechanism of CN destruction with chlorine and bromine chloride.

Jan 1, 1982

By R. W. Utley

The purpose of this study was to seek and evaluate possible relationships between the composition of coal refuse, as expressed by washability data, and factors affecting the product ion of a lightweight aggregate from refuse by bloating. The study was related to an intense program in the Department of Mineral Preparation at the Pennsylvania State University to study the possible elimination of air pollution from coal refuse fires by producing a low- carbon secondary refuse. Another phase of this program is considering possible uses of such a secondary refuse. Thus one study was to determine if a lightweight aggregate could be produced from this new refuse material and what effect the nature of refuse beneficiation would have upon the characteristics of a commercial aggregate product.

Jan 1, 1965

By Norman M. Junk

Following the wide-spread acceptance of ANFO as a useful, low cost blasting agent, studies have been made to adequately describe the physical and explosive properties of this material (1). As the quality of the AN blasting prill improved, reliability and sensitivity to initiation were greatly increased and many methods of priming were chosen from the standpoint of economics with little appreciation for the need to initiate so as to obtain the most efficient detonation. Under certain conditions, ANFO could be initiated with primers no more powerful than a No. 8 blasting cap (2). Research on primers for ANFO followed and it was demonstrated that this blasting agent was subject to extreme transient velocities upon initiation with wide variations in energy output depending upon the nature of the primer. For these reasons it was shown that powerful priming was economically justified (3). These studies helped to define the properties of an effective primer and the guides for its efficient use. In the vast surface coal mining industry, technological advances in earth moving equipment were paralleled by the development of larger and larger borehole drills (4). Even though ANM) was the major blasting agent used in this industry, investigations of priming techniques in these larger boreholes was almost non-existant. In 1962, Mr. Cleon Woolsey of Enos Coal Company disclosed to the industry that dramatic improvements in blasting production could be achieved with new priming and boostering methods (5). The research program at the Atlas laboratories was designed to explain these results and extend the study of initiation of ANFO with both high explosives and slurry explosives and to define the principles involved.

Jan 1, 1968

By S. E. Valji

Clay slurries are normally dewatered using flocculents like sulfuric acid or aluminum sulfate. This type of flocculation is based on the electrolytic mechanism. For certain clay dewatering applications, this method of flocculation is unsatisfactory. Flocculation, based on the bridging mechanism, using organic polymers has been utilized to overcome such problem situations. This method of flocculation offers solutions not possible by previous methods. Normally these flocculents are used to assist dewatering. In this case, not only is dewatering promoted, but also further processing is assisted by a change in the dilatant character of the filter cake that is formed. Discharge of filter cake is easier, extrusion of filter cake on to conveyor dryer is possible or improved, and heat transfer and drying rates of the extruded filter cake are substantially higher. Both natural and synthetic organic polymers have been utilized for this purpose. Selection, application techniques, and economics are described.

Jan 1, 1965

By S. S. Hsieh

The important carboxylic acid components of tall oils were tested individually as phosphate flotation reagents. These included C18 unsaturated fatty acids and C10 to C18 saturated fatty acids and resin acids. These experiments were conducted to evaluate such factors as the degree of unsaturation, hydrocarbon chain length, isomeric form, side-group modification, and cyclic structure. The effects of mineralogical characteristics on flotation response also were considered. The results of this systematic evaluation provide guidelines for selecting efficient substitute reagents and also provide fundamental data for further research on improved flotation technology.

Jan 1, 1980

By A. R. MacPherson

The procedure to arrive at an energy efficient autogenous grinding plant is carried out in the following steps: First Step - Determine power requirements to grind a particular ore. This work carried out on small samples ground in a 450 mm diameter Aerofall Hill and the results are checked against a standard Bond Index test. Second Step - A bulk sample from the ore zone is ground in a 1.8 m diameter pilot mill. This work is carried on until the power objectives as indicated from the first step have been realized. Third Step - Correlate the pilot mill data, with the data from the numerous samples ground in the small 450 mm mill and arrive at design criteria for the commercial plant. Ensure commercial mill design will be suitable to obtain similar results as those obtained in the pilot mill.

Jan 1, 1981

By Margaret Armstrong

The increasing cost of developing new mines and the need to mine more marginal deposits have led mining companies to use more sophisticated estimation methods such as kriging. But until recently, coal mining companies have shown little or no interest in these techniques. However, the stringent quality controls which are now placed on coal have led to a surge in interest in improved estimation methods. This can be seen from the -, number of research projects by private companies and governmental agencies on the application of geostatistics to coal reserve estimation. At present, most of these programs are centered on the problem of estimating the tonnage and the average grade (i.e. ash percent, sulphur content, calorific value, etc.) of the coal in-situ. See, for example, Sabourin (1975), Woods (1976, 1979), Pauncz and Nixon (1979) and Armstrong (1980). These studies show that the established techniques of linear geostatistics can be applied successfully to coal deposits. The study by Woods is particularly interesting because he had access to the actual production figures as well as the initial sample data from the no 2 seam in the Greenside Colliery owned by the Anglo-American Corporation. He showed that the estimates obtained by kriging were consistently closer to the actual production figures than those given by three other estimation methods. This confirms the superiority of kriging as a method of estimating block values for coal. Another advantage of geostatistics is that it can be used to determine the optimal spacing between drill holes. An example of this is given by Armstrong for the coking coal deposit in the Bowen Basin, Australia.

Jan 1, 1981

By L. S. Fountain

A national survey, 1978-1980, found 180,973 waste impoundments used by industrial mining, municipal and other interests. Possibly 27,000 contain hazardous materials. The potential hazard of leaks polluting water supplies is a growing concern. An electrical technique was developed to efficiently and speedily detect and locate leaks in geomembrane-lined liquid impoundments without emptying the contents. A potential applied between the liquid and earth causes electric current to flow through leaks in the insulating geomembrane material to ground. The cur- rent density around the leak is used to detect and locate the leak. Field tests show single and multiple leaks 2.54 cm in diameter or less can be detected and located to within less than 30 cm.

Jan 1, 1986

By M. J. Hrebar

Surface coal mine design has traditionally relied on graphic and analytic approaches for pit layout and equipment selection. A number of interactive graphic microcomputer programs have been written which aid in the design process in the academic arena and should also have industrial applications. The programs described include a dragline cut diagram and production index calculation program, a downslope load scraper cut diagram and volume program and an overburden volume and coal tonnage sequencing program.

Jan 1, 1985

By John L. Halls

Modern business practice dictates that in order to ensure the economic optimization of investment, the size of any investment venture must be such that every increment of capital invested in such a venture yields at least a corporate minimum acceptable rate of return. This practice is based on the premise that alternative investment opportunities capable of yielding the minimum corporate return are immediately available. If a mining corporation is to make the maximum use of its investment funds, any capital investment in a mining property must comply with the above practice. The most important parameter in estimating ore reserves is the cut-off grade which is used to separate material into ore or waste. The cut-off grade is calculated on the basis that material of cut-off grade produces sufficient revenue to cover the estimated costs of mining and processing through to sales, including depreciation and produce a pre-determined profit. Ore reserves so estimated are adequate for determining the magnitude of an orebody but do not provide a sound basis for determining plant size and therefore capital investment in a new property or for expansion consideration on an existing property. From a financial analysis of this one ore reserve it is impossible to ascertain whether each increment of capital investment is providing the minimum acceptable rate of return, Other difficulties associated with the calculation of a cut-off grade including the determination of depreciation and the amount of pre-determined profit to be included in the cut-off grade calculation are outlined in the text. The proposed solution to determine optimum ore reserves and plant size for new properties avoids the complication of calculating a cut-off grade by computing a series of ore inventories using arbitrarily selected cut-off grades. A comparison of the cash flows generated by production from such ore inventories using incremental financial analysis clearly indicates the ore reserve and plant size which will best serve the corporation's investment and metal production goals. Incremental financial analysis of a corporation's operating mines and prospects assists management in assessing the comparative expansion and investment possibilities of each property for increasing or maintaining metal production on a long term basis.

Jan 1, 1969

By Young C. Kim

Because of the tremendous technological advances achieved in recent years in microcomputers, it is not only technically feasible but also economically viable to develop an automatic truck dispatching system using a microcomputer. Such an effort was initiated by the Department of mining and Geological Engineering, University of Arizona in the summer of 1983. Up to date results and experiences prove that today's microcomputers can be economically employed for such a system to be used at small to medium scale open-pit mines. An IBM/XT microcomputer with 10 MB harddisk storage, together with automatic sensing capability of truck movements at several key locations in the pit, formed the core of this system. System software is written primarily in MICROSOFT FORTRAN with supporting subroutines in MACRO assembly language. The software is designed to automatically monitor truck movement throughout the pit, to make heuristic assignments based on expected shovel availability and truck travel times, and to record production statistics. It is currently dimensioned to handle 50 trucks, 10 shovels, 10 dump sites and 3 material types. Due to the lack of funds to purchase the necessary communications hardware, the work related to the automatic sensing of truck movements has not been performed to date. Otherwise, the automatic truck dispatching-system is fully operational on a realtime mode.

Jan 1, 1984

By F. G. Miller

It is generally accepted that sulfur exists in coal in three forms: (1) pyritic, (2) organic, and (3) sulfate sulfur. Sulfate sulfur usually makes up less than 1% of the total sulfur content. Pyritic and organic sulfur, make up almost all of the total sulfur and occur in varying amounts in different coals and can vary greatly in coal of the same seam Pyritic sulfurs of 20% to 80% of the total sulfur have been reported Other authors have shown that it is not possible to remove the organic sulfur without chemically altering the coal. Chapman and Jones (1) state: "Organic sulfur, unlike pyritic sulfur does not exist as discrete particles, but is intimately associated with the coal structure, and as such it is not possible to remove it or reduce its concentration by physical means." Any success in removing sulfur has come about by removing pyritic sulfur by physical means; therefore, removal of sulfur in the pyritic form is the subject of this investigation. The extent to which any impurities can be removed from a particular coal can be determined by a washability study. Outside of crushing coal, to finer sizes or chemically altering the coal, there are no known methods of changing this inherent washability characteristic. The efficiency of various methods used to remove impurities can be determined by comparison of results produced at a yield to the results as shown by a washability study. In recent years heavy media processes have proven their ability to wash plus 28 mesh coal and nearly produce results shown to be theoretically possible by the washability study. Therefore, it is the objective of this paper to show various methods of treating the finer fractions of the coal, in the hope of developing a process, which can effectively produce in the fine fractions the efficiency of heavy media devices in the coarse.

Jan 1, 1963

By P. E. Lenz

In Nevada, large deposits of diatomite were formed during the Miocene / Pliocene in deep, alkaline lakes. Associated sediments are predominately fine-grained lacustrine with varying fluvial-clastic layers. Tephra layers are common, and probably served as a source of soluble silica for the extensive diatom colonies. Four companies are currently producing diatomite from Nevada deposits. Nevada ranks second to California in annual domestic production. Nevada diatomite is used in filter aids, fillers, absorbents, catalyst supports, and many other products. Economics and mineral reserves indicate that diatomite production in Nevada will be significant well into the next century.

Jan 1, 1993

By Kostas Kaklis, Zach Agioutantis, Robin Flattery

Pillars are used as the primary support structures for underground mining to maintain stability by supporting the over laying strata. In the case of horizontal seams, the pillars are typically subjected to axial loading due to the weight of the overburden and/or abutment stresses, while in the case of inclined seams they are subjected to oblique loading due to both the vertical and horizontal in-situ stress.

By John W. Reddy

The C&NW Ore Dock at Escanaba, Michigan, is a major terminal on Lake Michigan for iron ore pellets arriving from the Marquette Iron Range located 112 km (70 miles) to the north. In an average year, the terminal handles in excess of 8 000 000 Mg (LT) of iron ore pellets consigned to a number of major steel companies. It is important to the steel companies for both cost control and operating efficiency that each cargo be sampled as accurately as possible in order to determine the physical and chemical properties of the pellets. This paper describes the equipment and operating procedures of the sampling facility and Presents some sampling data.

Jan 1, 1985

By V. T. McLemore

The Wind Mountain (WM) nepheline syenite deposit is part of the alkalic complex in the Cornudas Mountains, which ranges in age from 34.6 ± 1.5 Ma to 36.8 ± 0.6 Ma. The WM deposit consists of a complex, zoned pluton that ranges from syenite porphyry to nepheline syenite porphyry. The WM deposit has potential use for ceramics and dark-colored beverage containers and consists of nepheline, k-feldspar, albite, and varying amounts of other minerals. Analcime also is present locally but must be avoided because it is unsuitable for ceramic and glass. Chemically the deposit consists of 56-63 % SiO2 17-21 % Al2O3 and 4.0-5 % Fe2O3. Although initially iron is high, when the crushed rock is passed through a specialized magnetic separator, the iron content drops to below commercial maximum standards of less than 0.5% Fe2O3. The WM deposit is currently under exploration and testing to determine marketability.

Jan 1, 1994

By Robert J. Wright

The purpose of this paper is to propose a classification of uranium deposits that is believed to be well suited to the needs of uranium exploration and resource assessment. By way of background some observations are offered about mineral exploration in general, and uranium in particular. Attention is first given to the we of models in mineral exploration. Some general principles of mineral deposit classification, the basis for model formulation, are then considered. Finally, the uranium classification is presented.

Jan 1, 1979

By H. Sis

The pressure filtration behavior of dispersed and flocculated alumina slurries at high percent loadings is discussed with an objective to determine the effect of surfactant type and concentration on slurry properties. A high purity alumina powder was used as a model solid. Dispersion of the alumina was controlled by surfactants that are considered to act by electric and steric stabilizers. The effect of both the ionic and nonionic surfactants was investigated. Surface charge measurements of the slurries were carried out by electrokinetic sonic amplitude (ESA) method to understand the mechanisms. The effect of surfactant type and concentration on the kinetics of pressure filtration and final cake properties are discussed.

Jan 1, 1998

By George E. Summers

A salt dome appears to provide the basic medium requirements for the excavation of the 315 foot diameter, unsupported spherical cavity at a depth of 2700 feet required by the AEC in a proposed "decoupling" experiment. Tatum Salt Dome was a natural choice for a site because more geological and hydrological information has been accumulated on Tatum than any other salt dome on the Gulf Coast. The Tatum Dome is a mile in diameter, roughly flat topped, nearly cylindrical in shape and has some overhang at the top. The salt stock has nearly vertical layering of alternating bands of salt and anhydrite. In the vicinity of the dome, adequate fresh water for solution mining is available in surface streams and in subsurface aquifers. A saline aquifer is available for brine disposal. A tentative cavity location was selected near the center of the dome which meets the design criteria established by the AEC.

Jan 1, 1968

By S. S. Peng

High horizontal stress has been well recognized as a significant factor in roof control. It can adversely affect roof stability if the panel is designed improperly. Mining experience has shown that it can cause a cutter roof. The effects of high horizontal stress on roof stability depend on many factors such as magnitude and direction of the maximum principal horizontal stress, ratio of the maximum to minimum principal horizontal stress, structure and mechanical properties of the immediate roof and mining sequence. However, little is known about the intrinsic mechanism of high horizontal stress effect on roof stability except some conceptual explanations. In order to design a stable entry, the redistribution and concentration of high horizontal stress around the openings must be fully understood. Using the 3-D finite element analysis technique, this paper presents the redistribution and concentration of high horizontal stress field for a three-entry system with different orientations of horizontal stress. Based on the horizontal stress redistribution, possible roof failure for different orientations of horizontal stress is analyzed.

Jan 1, 1996