Blogs
Belts and Concrete Ore Passes
Conveyors were first used underground at Miami Copper Co., in the latter part of 1947. At that time some of the stoping area was too heavy and too close to the haulage level to use conventional haulage. To get the haulage drifts out from under the stoping area belt conveyors were used for the additional lateral transfer. Since 1947 more
Control Conveyor Belt Acceleration
Table of ContentsMathematical AnalysisStarting Time Control The part that acceleration plays in starting a belt conveyor and its effect on belt conveyor design are well understood in a general way. Its practical importance is easily overlooked, however, and under some conditions, it is absolutely necessary to give the problem of acceleration detailed study. Mathematical Analysis In working out the various
Dry Process Cement Plants
Table of ContentsRaw MaterialsGeneral Plant Layout and ConstructionDrying and Raw GrindingBurning and CoolingClinker Grinding The heavy postwar demand for Portland Cement has created shortages that are gradually being overcome by increases in plant capacity. In the postwar period, the Lone Star Cement Corp. has expanded several of its existing 15 plants and has built 2 new plants, now in operation,
Principles of Gravity Concentration
Table of ContentsMotion of a Particle in a Viscous FluidHindered SettlingClassificationOscillation PrincipleDense-Medium ProcessesJiggingLaundersShaking Tables Gravity concentration is a general term designating processes for separating and sorting granular material by means of forces that depend on the density, size and shape of the particles. When these forces are applied to the particles the latter are caused to move, those of a
Rod Milling Variables
Several constructive and fundamental studies have been made in the analysis of data obtained from experiments carried on with batch ball and rod mills. The operating characteristics of ball milling in small continuous circuits have also been appraised. It is from these analyses that some of the theories of comminution have been developed. Data presented in this paper are those
Acid Mine Water Drainage
Table of ContentsOriginal Mining Results in OxidationStream Pollution ProblemEffects of Discharges into River and Relative Reaction Acid mine-water drainage is a serious problem with many mines in the Tri-State zinc and lead mining district. Particularly is this true when large volumes must be considered in unwatering old mines that have refilled with water which has dissolved the products of oxidation
Factors Influencing the Performance of Single Retort Underfeed Stokers
Although the efficiency of coal utilization has improved steadily since the turn of the century as a result of continued research and development, little of this increase in efficiency can be credited to improvements in the single retort stoker. There are still numerous problems connected with the burning of coal on this type of unit, the solution of which would
Diamond Flotation
Experiments in the flotation of small diamonds from both kimberlite and alluvial deposits indicate the following conclusions: Water-repellent diamonds: Satisfactory flotation of —16 mesh diamonds, which are naturally water-repellent, may be accomplished using either Aerofloat 25 together with cresylic acid, or Du Pont B23 as frother together with kerosene as auxiliary oily conditioner or froth stiffener. The quantities of reagents
Sublevel Stoping in Small Mines
Table of ContentsApplicabilityStoping DetailsHaulage Level DevelopmentSublevelsStoping Sublevel stoping was first developed in the Michigan iron mines many years ago. Since that time this method, and modifications with long hole drilling, have been used in a number of non-ferrous mines and have been described in various papers and articles. With a few exceptions, the operations where sublevel methods have been applied
Metal Aging
Table of ContentsThe SequenceThe Contributing ReactionsProperties or the Coherent StateThe Property changes during AgingElectrical ResistanceLattice ParameterResistance to FlowDuctilityResistance to FractureAn Evaluation The correlation of property changes during precipitation with structure has progressed, sometimes rapidly but other times more slowly, since the fundamental discovery of Merica, Waltenberg and Scott. The predominant factor that hampered the progress has been limitations imposed by
What is Metallurgy
Table of ContentsMetallurgical EngineeringMineral DressingApplication MetallurgyPhysical Metallurgy Oh, please tell me what is metallurgy? There is no better way of paying tribute to the memory of a scientist than by developing and carrying forward those ideas which he has contributed to science and which are for us the very essence of his immortality. For a lecturer who has not had
Magnetic Roasting of Lean Ores
During the past few years a radically new process for the magnetic roasting of iron ores has been investigated and developed by Pickands Mather & Co. and the Erie Mining Co. in the Erie laboratory at Hibbing, Minn. This process, originally devised by Dr. P. H. Royster of Washington, D. C., involves the use of a roasting technique quite different
Coal Cleaning Equipment
Table of ContentsThe Correlation TheoryThe Correlation DataCapacity Comparisons The relative performance of coal washing equipment, or the effectiveness with which any type or make of equipment removes impurities from coal, has been most difficult to evaluate in the past. The most widely used yardstick is the Frazer and Yancey efficiency formula developed in 1922, but Yancey in a later article
Effects of Alkalinity on Lead Flotation
Table of ContentsAlkali Depression of Cerussite by Control of Carbonate Ion ConcentrationAlkali Decomposition of Lead XanthateAlkali Decomposition of Collector Coatings at Galena Surfaces Critical pH has been defined by Wark as that pH value below which a mineral will float and above which it will not float in solutions containing a given concentration of collector but free from other depressants
Pine Oil for Flotation Frother
Table of ContentsFrothability IndexFlotation with Pine Oil This paper presents the design and operation of a frothmeter capable of measuring the frothing characteristics of pine oils and other frothing reagents. The experimental data show that the frothability of pine oil is governed by: 1—rate of aeration, 2—time of aeration, 3—height of liquid column, 4—chemical composition of pine oil, 5—pH value
Mining Face Preparation
Table of ContentsAnthraciteEffect of Blasting Practices on Size in Run-of-mineEffect of Undercutting on the Sizes in Run-of-mineEffect of Mechanical Loading on Refuse in Run-of-mineBituminousChemical QualityVisible CleanlinessProcedureControl of SizesControl of MoistureExtraneous Impurities Anthracite Although the unmined anthracite will last for approximately 150 years, most of the thicker and cleaner coal beds have been almost entirely first-mined and pretty well robbed, leaving
Sinter Reduction
Table of ContentsPurification TheoryPrime Western Sintering CircuitHigh Grade Sintering CircuitSoft and Hard SinteringCottrells First, the relation between straight lime basic sinter’s susceptibility to disintegration and basicity was examined under various boundary conditions. Some selected results are shown in Figure 2: for variable fuel rates disintegration is governed by various influence factors: first, there is the well-known maximum as a function
New Solvent Extraction Techniques for Uranium Purification
This paper reviews several new applications of solvent extraction developed in conjunction with a research project carried out under the AEC Raw Materials Division by the Dow Western Division laboratories during the last two years. Several methods for direct solvent leaching of ores have been investigated by AEC contractors. The method studied at this laboratory is the only one that
How to Control Flotation Reagents
Reagent control in flotation is more an art than a science. Operators vary the amount of reagents used according to the metallurgy obtained. The amount of collector may be increased, for example, if tailings losses are high and decreased if concentrate grades are low. Often control decisions are based on only one assay, such as the tailings analysis by microscopic
Electric Furnace Melting of Copper
The final casting of refined copper has been restricted for generations by the following sequence of operations: Filling the reverberatory furnace, melting, skimming, blowing or flapping, and poling. The hoped-for 24 hr cycle, producing 300 tons or more, has been taken up largely with the necessary but time-consuming tasks of cleaning the bath, sulphur elimination, and in turn removal of
Metal Ethyl Xanthates Solubility
Table of ContentsExperimental MethodsExperimental ResultsDecomposition of Cupric Ethylxanthate The flotation system is usually distinguished from other physical chemical systems by the importance of interactions at the solid-liquid and solid-gas interfaces. In recent years, numerous quantitative studies have been made of the distribution of common collectors between the solid and aqueous solution phase. Although in flotation the main emphasis is placed
Morenci Smelter Arizona
Table of ContentsMetallurgySmelter Crushing Plant and Lime Burning PlantReverberatory FurnacesAnode PlantFlues and Stack Copper smelters of various kinds have operated in the Morenci district since 1872, but all have been abandoned with the exception of the present Morenci Smelter of Phelps Dodge Corporation, which was completed in 1942. During the five-year period starting in 1937, the Morenci ore body was
Arc Melting of Titanium Metal
Because of the reactivity of titanium metal with all known refractories and the common atmospheric gases, melting of the metal presents numerous problems. It is necessary to provide an inert atmosphere in the furnace as well as a crucible material that will not react with the molten metal, if a ductile ingot is to be produced. Two special furnaces have
Ultra-Fine Grinding and Classification
Fluid jet mills-employing a compressible fluid to grind materials to the sub-sieve range, was developed in the early 1930’s, and the subsequent acceptance of these units was the result of their ability to pulverize solids that, because of physical properties, could not be processed by other attrition methods, such as ball, pebble, and hammer mills. Also, the fluid energy pulverizer