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How to Test the Strength of Rocks
Table of ContentsBasic InvestigationsApplied Investigations: Relation Between Basic and Technological PropertiesCorrelation of Strength Properties with Density and AbsorptionCorrelation of Strength Properties with Rebound Hardness This paper reviews the progress made in testing the strength of rocks, ores, coal, salts, and other minerals as they are encountered in mine operations. It attempts to correlate the results of these physical measurements with
Mineral Jig Concentrator
Table of ContentsMINERAL JIG SIZING & DESIGN CAPACITY TABLESIMPLEX JIGDUPLEX JIGWORKING PRINCIPLE FOR EFFECTIVE JIGGINGTYPES OF JIGGING MACHINESJIG DRIVESHAND OF THE JIGJIG SIZES AND JIGGING CAPACITYHOW DOES A JIG WORKTYPES OF JIGSPRINCIPLES OF JIGGINGPrinciple 7—The Depth of a Jig Compartment Should be a MinimumIDEAL JIG STROKETHE BAUM JIGINSTALLATION OF THE BAUM JIGOPERATING SUGGESTIONS FOR THE BAUM JIGOTHER TYPES OF JIGSFaust JigElmore JigDenver
Gold Amalgamator
Grinding and amalgamating are practical and satisfactory methods for treating gold-bearing concentrates or black sands or for cleaning up a mill. The gold is brightened and made more amalgamable. The tailings might be rich enough for cyaniding. Figure 137 shows an amalgamation barrel. Laboratory ball- mills and the smaller of the ball-mills (amalgam gets behind liners in these) used in
Electrowinning
Electrowinning is defined as the cathodic deposition of metal, in this example copper, from a copper bearing solution by the passage of an electric current current using an insoluble anode. For copper the electrowinning reaction reaction is: CuSO4 + H2O ⇒ Cu + ½O2 + H2SO4 The overall reaction is the combination of two electrochemical half reactions. The cathodic reaction
How Centrifugal Forces Applies to Gravitational Classifiers
For many years gravitational classification has been employed as a basic tool in beneficiation of minerals and coal. While improvements have been made to increase efficiency and fields of application, the basic flow pattern has remained relatively unchanged in most gravitational classifiers. Feed slurry is introduced into a settling pool wherein the coarser solids settle against either an upward or
Ball Mill Capacity and Power Consumption Relationship to Mill Speed
The accepted basis of comparisons between mills of different diameter is the percentage critical speed. If n = actual mill speed, rpm, nc = calculated critical speed, rpm, np = calculated percentage critical speed, and D = inside diameter of the mill in feet, In the following analysis capacity, T, is expressed in short tons per hour, tph, and power
National Instruments NI 43-101 Technical Reports
Table of ContentsNI 43-101 ReportsContents of a 43-101 ReportSources of NI-43-101 Technical ReportsNational Instruments NI 43-101 Qualified PersonConsents of Qualified PersonsSources of Qualified Persons National Instrument (NI) 43-101 is a Canadian mineral resource classification system used to guide the disclosure of information related to mineral properties. Any company, foreign or domestic that lists on stock exchanges overseen by the Canadian
A Physical Explanation of the Empirical Laws of Comminution
The laws of comminution of Kick and Rittinger have been debated for many years. Certain data obtained from ball mill and drop tests are found to be in approximate agreement with Rittinger’s law while other data would seem to support Kick’s law. In all these tests the energy required to produce a wide variety of particle sizes has been studied.
Flotation Theory Molecular Interactions Between Frothers and Collectors at Solid-Liquid-Air Interfaces
Froth flotation is usually effected by the addition of a collector agent and a frothing agent to an aqueous suspension of suitably comminuted mineral ores. The action of collectors is to adsorb onto the surfaces of minerals to be separated, sensitizing them to bubble adherence. The action of frothers has, in the past, been accepted as that of froth formation
Theory of Comminution
H. J. Kamack (E. I. du Pont de Nemours & Co., Inc., Wilmington, Del.)—Rittinger’s law usually is stated to the following effect: “The work (or energy) consumed in particle size reduction is proportional to the new surface area produced.” The law has been stated substantially in this way by Taggart, Berry, Dalla Valle, Coghill and DeVaney, Richards and Locke, Gross
Surface Tension of Solid Gold
In the original Udin, Shaler, and Wulff technique for measuring the surface tension of copper, variously weighted wires were allowed to extend or contract in a copper cell held at elevated temperatures in vacuum. By plotting stress vs. strain for a wire array in one test, the stress at zero strain is obtained. This is the point where the contractile
Cadmium Recovery from Lead
Table of ContentsPreparatory ProcessingPort Pirie Works—Broken Hill Associated Pty., Ltd., Port Pirie, AustraliaLeaching and Purification PracticeSponge Precipitation PracticeMetal Recovery OperationsRefining and Casting Practice Greenockite is the only known cadmium mineral of importance. It occurs rather universally, in minor concentrations, as a secondary mineral in sphalerite deposits. The world’s cadmium output is obtained through the processing of metallurgical by-products, largely from
Re-solution of Precipitated Silver in Copper-Silver Alloys
During preliminary tests on the aging of a Cu-plus 5 pct Ag alloy, a specimen which had been overaged 24 hr at 550°C was annealed in a nitrogen-hydrogen atmosphere first for 2 hr and then for an additional 28 hr at 600° C. Conceivably, for Cu-Ag alloys, the matrix-transition-precipitate precipitation sequence is reversible for the re-solution of the precipitate caused
Flotation Characteristics of Pyrrhotite with Xanthates
Table of ContentsExperimental ResultsDiscussion of Results Pyrrhotite has long been considered a gangue mineral to be eliminated as tailing in the treatment of various sulphide ores. However, in recent years the world-wide lack of sulphur resources has called attention to this mineral as a potential source of both sulphur and iron. Its importance as an economic mineral, however, has not
Squeeze Cementing
Table of ContentsPreliminary StudiesField Investigation to Determine Proper Squeeze Cementing Methods Laboratory and field testing of various squeeze cementing techniques and materials revealed that many improvements could be made in squeeze cementing operations. The use of a slow-pumping squeeze cementing procedure permitted the control of the quantity of cement displaced into a formation and aided in obtaining a high final
Photoelectric Sorting of Optical Fluorspar
The crystal laboratory, Dept. of Physics, Massachusetts Institute of Technology, was confronted with the problem of obtaining a supply of optical grade calcium fluoride (CaF2) for use in growing synthetic CaF2 crystals. A search of the known fluorspar deposits did not indicate that any quantity of optical spar could be obtained. Even the best material had to be sorted by
Convertol Process
In the last several years the coal industry has intensified its effort to solve the growing problem of cleaning and recovering fine mesh coals. On one hand there has been increasing civic pressure for cleaner streams, and on the other hand there has been increasing production of fine mesh coal, resulting directly from adoption of the modern mining methods so
Low Melting Gallium Alloys
Table of ContentsExperimental ResultsAlloys Containing AluminumDilution of Ga-Sn-Zn Eutectic In recent years, the interest in liquid metals as heat-transfer media for power plants has been very great. The possibility of the development of nuclear power plants has increased this interest and served as the impetus behind much research on low melting metals and alloys for such purposes. The principal reasons
Effect of Rare-Earth Metals on the Properties of Extruded Magnesium
The effects of rare-earth metals on the properties of sand-cast magnesium were discussed in some detail in earlier paper by the author. The present paper deals with the effect of the same alloying elements on the properties of extruded magnesium. This investigation also had as its aim the development of a wrought alloy having a better combination of room-temperature strength
Comparison of Overflow and End Peripheral Discharge Mills
In a previous article the authors outlined a study of the variables in rod milling and also reported data from a series of open circuit grinding tests on a massive limestone in a 30-in. x 4-ft end peripheral discharge rod mill. As a second part of the experimental program, an analysis is now presented for the 30-in. x 4-ft overflow
Autogenous Roasting of Low Grade Zinc
Table of ContentsFurnace DesignDesign and Arrangement of Rabble TeethOperationRoasting Characteristics of Feed Components The operations of the Electrolytic Zinc Co. of Australasia Ltd. involve the preliminary roasting of zinc concentrate from Broken Hill, New South Wales, at a number of acid-making centers on the Australian mainland. The partially roasted material is shipped to the Tasmanian plant where it was formerly
How to Dry Coal
Table of ContentsDewateringHeat DryingVolume of Gases RequiredFurnace RequiredCold Air DuctsHot Gases DuctsRegenerationDrying Characteristics Moisture in coal must be considered as an impurity, just the same as ash, from the standpoint of utilization of the coal. Being incombustible, it reduces directly the heating value of the coal, and in addition absorbs heat for its evaporation. Its presence means useless expenditures in
Fractured Limestone Cores
Table of ContentsCore Analysis ProcedureFluid Saturations and PorosityPermeabilityFluid Saturations and PorosityPermeabilityAnalysis Results For Typical FormationsMatrix MeasurementsAverage Data for Several Formations A method is outlined for the analysis of large cores, developed primarily for the purpose of obtaining reliable data on fractured or vugular limestones. Porosity and fluid saturations are determined by a modified Dean-Stark extraction after initially bringing the samples
Dewatering of Tailing
Table of ContentsInitial ConsiderationsElectrical Dewatering TestsEffect of Deposition TimeEffect of Dispersant Chemical The phosphate ores mined in middle Tennessee typically consist of granular rock phosphate particles disseminated in a clayey matrix. In the TVA plant near Columbia, Tenn., the phosphate ore is mined, made into a slurry with the addition of a small amount of sodium hydroxide as dispersant, and