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By T. W. White

One of the objectives of today's mine superintendent is to increase his equipment availability. To this end we have seen improved scheduling procedures, preventive maintenance programs and extensive drive training and operating procedures. However, until recently, one area that has changed little in the past twenty years is the method of refueling and servicing mine equipment. In looking at mines across the country continually one encounters the hazardous oil soaked ground, the hand held fuel nozzle and the maze of hoses of the "traditional" fuel stop. By adapting technology developed in the construction and aircraft industry, current fueling and servicing practices can be easily improved. The result will be less nonproductive time, less downtime from engine failures and increased security from major refueling fires. The time saved almost amounts to having another truck in the fleet! One feature of the improved servicing practice is the implementation of high flow fueling. For trucks now on the market, a flow rate between 120 and 150 gam is feasible, about 90 gam greater than current practice. This flow rate could be increased even further as larger trucks come into use. A second idea borrowed from the aircraft industry is the use of positive lock type connection nozzles that automatically shut off when flow stops. These may be used for fuel, water, oil and hydraulic systems to eliminate spillage and assure that clean fuel, oils, and water are delivered to the vehicles. The reduction of fuel spillage lessens the threat of major fires resulting: in equipment damage and loss. Eliminating fire hazards will become even more important as the turbine engine with its lighter, more volatile fuels come into common use.

Jan 1, 1972

By T. Skodack

This presentation will compare actual work site results for the loading and transport of shot rock for two major tunneling projects in North America. "SCARMAR" (the Canadian subsidiary of S & M Construction) is operating a rail bound Hagglund continuous gathering arm loader in combination with a Hagglund nine car shuttletrain system at the West End of Table Mountain on the B.C. Railway project near Tumbler Ridge, Canada. Al Johnson Construction is operating a Hagglund rubber tired continuous gathering arm loader in combination with haul trucks at the Rocky Mountain Pump Storage Project near Rome, GA. This paper will compare: 1) tunnel and ground conditions, 2) the total work cycle as it relates to mucking and haulage 3) efficiencies and related problems with the two systems 4) mucking and haulage rates 5) operating costs, and 6) recommendations for future large tunnel excavations. Manuscript not received in time for publication.

Jan 1, 1983

By Floyd M. Thorman

Gypsum is the crystalline chemical compound CaS04?2H20. A close chemical relation - and frequently occurring with Gypsum ? is Anhydrite which is Cask. Gypsun has wide commercial use because relatively simple heat processing reduces it to Plaster of Paris. While Anhydrite can be converted to Gypsum and thence to Plaster of Paris, the procedure is not simple and is quite costly. Anhydrite, however does have use in the agricultural field and in the Portland Cement industry. Occurrence of Gypsum in the earth structure is usually near or at the surface. Most underground mining is at 60 to 100 feet although one mine in southwest Virginia reaches a depth of 1300 feet. Gypsum is one of our softest minerals, rating only 2.0 on the Mohs scale of hardness. Specific gravity is 2.3 to 2.4. It is soluble in water but only slightly so. Interestingly, it is more soluble in cold water than in hot. For example, one part Gypsum dissolves in 370 parts water at 106° Fahrenheit while at 212°F. the water requirement is 452 parts. Compressive strength of massive Gypsum runs about 3000 lbs. per square inch. Color ranges from grey and brownish-grey to white.

Jan 1, 1973

By G. W. Douglas

The need for dimensionally stable filled polymer composites has spurred the quest for materials that possess a negative coefficient of thermal expansion (CTE). Finding minerals and materials with a negative CTE large enough to counteract the substantial CTE found in polymers proves challenging. Much research has been per-formed over the last decade to uncover various materials that possess this unusual behavior. A list of materials that have demonstrated negative properties are discussed, as well as the experimental use of one such material (ZrW2O8), in a polymer matrix composite. Other negative properties, such as negative Poisson?s ratio and negative stiffness, are also examined. Key words: Negative properties, Coefficient of thermal expansion, Zirconium tungstate

Jan 1, 2010

By R. Venugopal, V. K. Saxena, Veerendra Singh

"Ore morphology plays a vital role during the milling and liberation of minerals. This study was carried out to understand the role of mineral crystallography and mineral interfaces on the milling and liberation processes. Data related to mineral crystallography, Vickers Hardness Number and beneficiation processes were collected from literature, and detailed statistical analysis was conducted to relate these parameters. Review of the crystallographic information of minerals present in ores indicates that molecular weight and cell parameters significantly affect milling and liberation characteristics. Mineral interfaces were classified into the three categories of coherent crystals, semi-coherent and incoherent crystals, and breakage behaviors were studied. The studied cases revealed that these material interfaces control the micropore properties that play a vital role in the initiation of intergranular and intercrystalline fractures which occur in siliceous manganese ores and dolomite as a result of thermal treatment. In contrast, banded hematite jasper and coal exhibited a much more complex fracture pattern due to their coherent interfaces and finer physical associations. This study explains the effect of the various types of interfaces on milling, and the approach can be helpful in developing a methodology to enhance mineral liberation with minimum energy consumption.IntroductionComminution is a vital unit operation in the mineralprocessing, cement-making, power-generation and pharmaceutical industries. Its importance in mineral beneficiation operations is increasing every year as a result of the growing need to exploit lower-grade ore bodies and process reject materials (Blazy et al., 1994; DOE, 2005). Low-grade ores require significant energy during grinding to liberate the valuable minerals, which are further separated from the gangues by various beneficiation methods. Various attempts have been made to enhance mineral liberation during grinding to minimize energy consumption. Most of these studies focused on the analyses of the compression mechanism, chemical additives, thermal treatment, microwave treatment and electric disintegration (Klimpel and Austin, 1982; Norgate and Weller, 1994; Bearman et al., 1997; Kumar et al., 2010; Wang et al., 2011; Singh et al., 2012). However, many of these efforts had limited success, and there is a need to see the problem from a fresh perspective."

Jan 1, 2015

By C. A. F. Pinto

In the present work compared flotation kinetics of apatite with four different collectors was established. Sodium oleate and rice bra~ oil were used to represent conventional collectors. The new collectors included a sulfosuccinate and a sulfosuccinamate. It was observed that the collection ability of each reagent was very dependent upon the mineral size ranges. The results-were analyzed in terms of size-by-size recovery curves. Flotation rates were also very dependent on size ranges of the mineral particles. One of the new collectors displayed higher flotation rates for coarser particles than the other reagents tested. Synergetic effects were also apparent when a conventional collector was mixed to a new collector.

Jan 1, 1991

By David G. Chedgy, Edward A. Zawadzki, Robert D. Stoessner

Extensive research and testing in commercial facilities has clearly demonstrated that heavy medium cyclones are the most effective process for cleaning a 0.6 x 0.15mm (28 x 100 Mesh) coal at low separating gravities, less than 1.35. This paper describes testing performed to deter- mine system characteristics at these lower gravities and the type of circuitry required to maximize performance. The results of these studies include both pilot and commercial scale tests of cleaning 0.6 x 015mm (28 x100M) coal.

Jan 1, 1988

By Walter C. Labys

This paper reports on recent modeling efforts to analyze the eastern U.S. steam coal market with a cross-sectional econometric as well as a quadratic programming approach. The background to coal modeling is examined first. The particular aspect of the steam coal market to be modeled are then presented and the corresponding coal model described. Both empirical results and rigorous mathematic pertubation analysis are presented. Conclusions are then drawn regarding potential modeling applications in the policy area.

Jan 1, 1979

By R. A. Ynchausti

In January 1993, Pyramid Resources began implementation of a supervisory expert control system at a U.S Cu concentrator. The objective of this control system was to improve plant profitability through unit operation optimization and integration. This paper documents the key aspects of the project, including: economic and associated benefits, system architecture, concepts of implementation, process control strategies, practical aspects of implementation and conclusions. The implementation of expert control at this concentrator has resulted in an estimated benefit of $50,500 per day. This is a net result of improved tonnage, reduced reagent consumption, improved concentrate grade and reduced energy per ton produced.

Jan 1, 1995

By James A. Clum

The shift to lower grade iron ores, e.g., magnetic taconites, resulted in a shift towards agglomeration practices which could effectively deal with the fine particle sizes generated in the liberation and concentration processes. If the iron bearing particles are not extremely fine, e.g., -1/2 in + 100 mesh, sintering is an adequate means of agglomeration.(1) For the more dispersed ores which result in fine concentrates (more than 80%,-325 mesh), the fine particles must be agglomerated by mechanical means before final hardening, e.g., pelletizing.(1) In the pelletizing process, the essentially mechanical step of balling is extremely critical since the strength of the pre-fired pellet determines the firing conditions. The ability of the proper amount of moisture to hold together a ball of the very fine ore concentrate particles has long been recognized. It is a charac¬teristic of the reaction at the interface between the ionic solid of the ore concentrate and the polar water phase which overlays the solids. The strength in such moisture laden balls, the green strength, is a strong function of the water content (Figure 1) and thus deteriorates rapidly for either a small excess or a small deficiency of moisture. For purposes of commercial practice, the control of green ball handling properties by accurate control of ball moisture is too demanding. Moreover, as the ball is heated towards its hardening tempera¬ture, e.g., 1300'C, there is a substantial drying reaction which would lead to such a low dry strength of the ball that it would not support its own weight much less the weight of other balls in a firing furnace.

Jan 1, 1976

By J. M. Goris

The U.S. Bureau of Mines, in cooperation with the Homestake Mining Co., and the University of Utah, is conducting a field demonstration to evaluate the behavior of rock masses supported with cable bolts. One of two rock masses being studied is supported with both conventional and birdcage cables. This rock mass is located between the 6500 and 6650 levels of the 45-4BN stope. 21 ledge. The second rock mass is the hanging wall of the D-limb stope between the 3500 and 3650 levels near the Ross Shaft and is supported with conventional cables. The primary objectives of the project are to monitor the behavior of the two rock masses during mining using extensometers and cable support strain gauges, after which the rock will be modeled using the finite-element code UTAH III. Field data will be used to verify the modeling. In addition. a comparison between the effectiveness of conventional and birdcage cables will be made.

Jan 1, 1991

By Yi Yang, CHENGLONG XU, HAORAN LI, YALI FENG, JINRONG JU

Steel slag is an industrial byproduct of steelmaking that is mainly composed of calcium, iron, silicon and magnesium. In addition, depending on the different raw materials entering the furnace, steel slag contains a certain amount of vanadium that is the main source of vanadium production, accounting for 69 percent of the species of the total vanadium raw material [1]. From experience, the production of one ton of steel will generate 1.0 to 1.5 tons of steel slag [2]. However, the utilization efficiency of steel slag is less than 30 percent, and a large amount of steel slag is identified as waste and stacked in tailings. The random stacking of steel slag not only wastes large amounts of limited steel and land resources but also exerts pressure on the environment [3], making it imperative to research the effective utilization of steel slag and recycling of metal resources.

By B. R. Pothini, H. von Schonfeldt

In underground coal mining many excavated openings have a relatively short projected life span. To ensure safety for men and materials at a minimum cost over the projected operating life, only pillars for overburden support and roof bolts for support of the openings are used extensively. Mining activity constantly changes the geometry of the mine producing load changes on the structural support members of the openings that often induce unstable deformations which can lead to roof falls or pillar failures. The paper describes how simple deformation measurements can be used to design primary and supplementary roof supports and to predict roof falls and possibly pillar bumps. Specifically, bed separations in the roof measured directly with the help of borescopes and calculated from differential convergence data are used to optimize bolt links or support requirements for chemical stabilization of mine roofs. Roof falls are predicted on the basis of admissible values for cumulative convergence between roof and floor, convergence rate, and the change of the rate of convergence. The pillar extraction operations convergence anomalies detected from contouring identify bump prone pillars, while convergence and pillar dilation determine the yield zone in a pillar to verify pillar softening and de-stressing. Manuscript not received in time for publication.

Jan 1, 1983

By Eivind B. Jensen

Introduction Though temporarily shutdown due to the depressed economy, the Henderson mine is a large underground molybdenite producer, using a continuous panel-caving mining system. The location of the ore body requires access from the surface through three shafts, the collars of which are located about 3.15 km (10,350 ft) above sea level. At this altitude, normal temperatures are such that heat must be added to intake-ventilation air for about half of each year. This prevents ice from building up in the intake shafts, waterlines from freezing underground, employee discomfort, and equipment-related problems such as pneumatic rock drill icing and cold starting of diesel engines. Because of topographic and environmental constraints, the Henderson mill and concentrator are located 24 km (15 miles) from the mine, on the west side of the Continental Divide. All ore from the mine is transported to the mill by an electrified rail haulage system, with 15.4 km (9.6 miles) of the trip being underground through a double-track tunnel. A shaft at the midpoint of the tunnel exhausts air drawn from the mine and from the portal that is at an elevation of 2.7 km (8,950 ft). Intake air at the portal must be heated for part of the year to prevent ice buildup. Mine Ventilation System The mine ventilation system uses three sources of fresh air and two exhausts. The primary freshair intake is No. 3 shaft. It is concrete lined to a diameter of 7 m (23 ft) for a total depth of 698 m (2,291 ft). An airflow of 755 m3/s (1.6 mil¬lion cfm) is supplied to this shaft by two vane-axial 932-kW (1,250-hp) fans on the surface. The air is distributed within the mine by means of fresh-air distribution levels connected to production and development levels by raises. A secondary source of fresh air to the mine is provided by No. 2 shaft, the primary man and material access. This shaft is concrete lined to a diameter of 8.5 m (28 ft) for a total depth of 946 m (3,105 ft). Downcast airflow is induced by a pressure differential produced by the fans in the system such that net intake and exhaust volumes are equal. The No. 2 shaft flow of 165 m3/s (350,000 cfm) enters the mine network from the production and haulage levels. Exhaust air is moved from the various working levels through connecting raises to exhaust col¬lection levels that return it to No. 1 shaft. No. 1 shaft is the primary mine exhaust. It is concrete lined to a diameter of 7 m (23 ft) for a total depth of 788 m (2,584 ft). Three vane-axial 932-kW (1,250-hp) exhaust fans are located at the collar of No. 1 shaft, producing a flow of 850 m3/s (1.8 million cfm). In addition, an airflow of 71 m3/s (150,000 cfm) from the intake distribution level is exhausted via the haulage tunnel, by means of No. 4 shaft located midway in the tunnel. The main features of the mine ventilation network are summarized in Fig. 1. Ventilation Air-Heat Plants No. 3 Shaft In the early design phase of No. 3 shaft, it was recognized that air heating would be required to maintain underground temperatures above 0°C (32°F) during cold winters in the Colorado mountains. When the air reaches the mining

Jan 1, 1983

By G. B. Misra

Heat transfer in partially wet mine airways has been the subject of study for quite some time. Of the available models some are quite empirical while some involve highly complicated computation. Models developed by Amano, Mizuta and Hiramatsu and Banerjee and Chernyak as well as that modified by Misra were evaluated for prediction of the rise in temperature and humidity (mixing ratio ) of partially wet mine airways at four different levels in the Mosaboni Mine of Hindustan Copper Ltd. Measurements of barometric pressure, virgin-rock temperature and changes in dry- and wet-bulb temperatures along a certain length of airway were made. The rise in dry-bulb temperature and mixing ratio of air over the sections were calculated using the three models. The study reveals that calculated values of temperature and moisture content agree within possible rage of experimental error with all the three models in case of three levels with low wetness factor, but the agreement was poor for the relatively more wet airway on the 30th level. Errors in the estimation of fw to the tune of 0.025 can lead to fair error up to 0.94 K in the estimated temperature while alternative ways of estimating the heat transfer coefficient [] can introduce errors up to 1.45 K.

Jan 1, 1987

By J. Richard Tonry

In portland cement manufacturing, the raw materials axe changed to clinker in the burning operation. Generally the rotary kiln is used for this purpose and involves many processes, including pelletizing and nodelizing. This transformation is called clinkering, and is analyzed as now generally practiced in cement making, from the raw material to the resulting clinker.

Jan 1, 1963

By Otto E. Zwanzig

You may think long before this talk has been completed that the speaker is belaboring the obvious. Please let me put to rest here and now any doubt which you may have in this regard by assuring you that is precisely my intent, and for a very specific reason. We all profess to know and recognize the obvious, but I am impressed increasingly how often we forget or fail to act upon the obvious. Shortly after starting my first job upon graduation from college, I was asked by my boss to participate in a course on practical communications, particularly as applied to conveying proposals effectively to the client -- be he customer or company president. The concept or philosophy underlying this program was so simple and obvious that in my youthful brashness I saw only a gross waste by the company of e good, solid $1930 in compelling me to take the course. The sequel to this experience occurred about five yews ago when I was directing a 300-man marketing group. At that time I enrolled a dozen of my department heads, and subsequently about a hundred other personnel, in the contemporary version of that sane program. Why? -- because they all knew the obvious, but I could see how imperfectly they were implementing it. Truly, a wide chasm exists all too often in our beliefs on the one hand and our practices on the other.

Jan 1, 1962

By Peter N. Yanker

The two types of dryers used in the drying of copper concentrates are the rotary dryer and the spray dryer. The rotary dryer has until recent history been the traditional drying method used, Although spray dryers have been used in the chemical field for many years it is only recently that they have been accepted for drying of copper concentrates. The comparison made here will apply in a narrower sense to the drying of copper concentrates as fed into the reverbatory furnaces of the Smelter. To compare a rotary dryer and a spray dryer, which are two totally different methods and pieces of equipment, it is best to view them as systems each made up of certain elements

Jan 1, 1976

By Harrison H. Roberts

A. We are aware that many who are in the audience have perhaps heard before some of the material which will be presented. Since our firm is more closely associated with the heavy construction industry our experience is more oriented in that direction. Notwithstanding this, the subject your program committee has asked us to present centers mainly in the earth-moving field. We find a common denominator between say, the stripping of a site to uncover an ore-body which will be developed by open-pit methods, and that of excavating & transporting materials for an embankment dam, airport or other project. Both are earth-moving problems and we offer for your consideration a means of determining the most favorable method, equipment selection and resultant cost. We do considerable studies involving rock excavation for tunnels, underground powerhouses, inclined and vertical shafts for penstocks, muck-removal, electrical cable & other related underground work. Hence, we believe we speak the same language.

Jan 1, 1972

By Fiona M. Doyle, Christopher R. Lubeck, Michael C. Chin

The fundamentals behind a novel approach for creating inorganic/polymer hybrids are described. The binding of +2 charged ions, specifically Cue-and Cat+, to ionic functional groups is explored through UV-Vis spectroscopy and zeta potential measurements. The novel approach uses an electric field to drive ions into a functionalized polymeric matrix, thereby inducing the precipitation of calcium phosphate species. Scanning electron microscopy images of the resulting composite illustrate the results of these precipitations with two distinct morphologies observed.

Jan 1, 2003