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Manganese Steel Allotropic Theory
Table of ContentsSteel UsedHeat TreatmentsManganese Steel Bar Heated to 1,100° C. Quenched in WaterManganese Steel Bar Heated to 1,100° Slowly Cooled in the FurnaceManganese Steel Bar Heated to 800° for 2 hr. Slowly Cooled in the FurnaceManganese Steel Bar Heated to 700° for 2 hr. Slowly Cooled in FurnaceManganese Steel Bar Heated to 600° for 2 hr. Slowly Cooled in
Conical Ball Mills VS Chilean Pan Mills
In view of the prominence which the conical mill has attained in the fine-crushing field within the few years since its introduction, the following comparison with its more mature forerunner, the Chilean mill, based on extensive tests, is submitted in the interest of the milling profession. Soon after designing the concentrating plant, the conical Ball mill made its appearance in the
Hardinge Conical Mill – Grinding Efficiency Compared
Table of ContentsBall Mill LiningSpeed of Ball MillsCompare a Hardinge Ball Mill to Chilean Pan MillPerformance Comparison: Conical Ball Mills VS Cylindrical Ball Mills Nearly every mining and metallurgical engineer will recall his early experience and method of producing step- or stage- reduction in preparing ore-samples for assay, in which he employed idea, step- or stage-reduction simply because it was a self-evident
Placer Gold Mining in Colombia
In giving my opinion of the importance of Colombia as a field for investment for those interested in mining for the precious metals, I must begin by quoting Sir Clement Markham, who, in one of his presidential addresses to the Royal Geographical Society of Great Britain, called the attention of its members to the fact that “ although Colombia is
How to Generate Steam Energy from Furnace Waste Heat
Table of ContentsSelecting a Boiler SystemWaste Gas Boilers for Directly Fired Heating FurnacesUtilization of Waste Heat from Regenerative Furnaces Technical progress takes place in two directions: the improvement of methods, affecting the quality of the product; and increase in the economy of operations, affecting its cost. In the iron-industry, practice is pretty well settled, and revolutionary changes of method are, for the present,
Gay-Lussac Assay Method of Silver Determination
This old and well-known method of determining silver is, in bullion work, so far superior to the furnace-assay that it is looked upon with reverential awe by many, if not by most, users, and its ease of execution, with proper equipment, commends it highly where much commercial bullion work on silver is required. The method is so thoroughly well known
Electrostatic Concentration Ores & Minerals
Electrostatic separation of ores in its present form is generally known as the Huff process, from the name of Charles H. Huff, of Boston, Mass., through whose constant and persistent labors (with the invention of Clinton E. Dolbear as a basis) the successful commercial process embracing separative machinery and the various electrifying devices has been developed step by step, and
Electric Miner’s Lamp
Torches were used by the early Romans for mine-lighting, and these were followed by open lamps or earthen jars filled with tallow or oil, and later by candles. In early coal-mining, explosive gases seldom occurred, and, if they were encountered, the danger of explosion was materially diminished by the absence of any ventilating-system and the consequent insufficient circulation of air
Assay Determination of Platinum in Ore & Gold Bullion
By the old method of determining platinum in ores and bullion, the silver-alloy first obtained in the regular course of assay is parted in strong sulphuric acid and the residual metal weighed. This is re-alloyed with silver by a second cupellation and parted in nitric acid, the residual metal being again weighed. Any difference shown between the two weighings is
Curves for the Sensible Heat Capacity of Furnace Gases
Table of ContentsExperimental Data on the Specific Heat of GasesSpecific-Heat Equations & DerivationHeat-Capacity CurvesConstruction and General ApplicationApplication in Metallurgical CalculationsExample 1Example 2Example 3Example 4Appendix AAppendix BDerivation of Formula Theoretical Temperature of Combustion Knowledge of the thermal capacity of gases is of great importance in making metallurgical calculations. The metallurgist is frequently called upon to investigate and determine furnace efficiencies in which the heat carried
Copper Smelting Furnace
The early development of the reverberatory furnace for smelting copper ores was the work of the Welsh smelters, particularly those of Swansea. The first record of a reverberatory furnace is made by Jars, who states that copper-smelting was effected in reverberatory furnaces at Middleton-Tyas, in Yorkshire, England. The first patent, of any importance, for improvements in reverberatory furnaces was granted
Chloridizing Leaching
Table of ContentsDevelopment of the Chloridizing Leaching ProcessThe PlantImportance of Proper MixingHolt-Dern RoasterLeaching ProcessLeaching CostsPrecipitationPumpsConclusions Outline of the Chloridizing Leaching Process: The Mines Operating Co.’s plant at Park City, Utah, was designed to treat the low-grade fillings in the old stopes of the Ontario mine. These fillings carry 6 to 14 oz. of silver, 1 to 2 lb. copper, 0.01 to
Assay of Gold and Silver by the Iron-Nail Method
Table of ContentsPreparation of the Gold-Bearing MaterialPreparation of Silver SulphideAssay of the Gold- and Silver-Bearing MaterialsConclusionsDiscussion The iron-nail method of assaying has been used for a number of years, but has not met with the approval of all assayers. The method possesses advantages which may be given as follows: (1) no preliminary treatment is required; (2) a lead button of
Assaying for Silver and Gold
From time immemorial the methods of assaying any materials for silver and gold were in reality nothing but laboratory smelting methods. The writer arrived in Butte, Mont., he found that these metals, contained in copper bullion, were still determined by the all-fire assay, both in the same charge. There seems to be no record as to when and where the
Copper Bullion Assay
Table of ContentsStock solutionsAssaying for Silver and GoldRemoval of Selenium and Tellurium Someone some time ago remarked that some chemists still insist on telling us how to determine copper by the electrolytic method. The writer must confess that he believes that everything is not known definitely as yet as to how the exact amount of copper is determined in such
Wood Burning Assay Furnace
Wood burning assay furnaces are made with single and double muffles and are much like the soft coal furnaces except that a larger firebox and grate are used. Wood is usually sawed in 2-foot lengths and with dry wood the muffle may be easily heated sufficiently for assaying. Hard wood is much to be preferred as it does not bum
How to Estimate the Tin Content: Assay Determination
Table of ContentsTin Fire Assaying MethodsWet Assay MethodsDetermination Method AdvocatedAlternative Determination MethodsMethods of Reducing Stannic SolutionsMethod of Titration with Standard Ferric ChlorideConclusion The object that the writer has mainly in view in presenting this paper is to draw the attention of those connected with the technical side of the industry to the unsatisfactory and by no means up-to-date methods employed in estimating the tin
Electrolytic Refining: Silver – Gold – Copper
Table of ContentsSilver RefiningHow to Refine Silver with ElectrolysisSilver Refining EquipmentOperation and ProductsGold RefiningRefining Gold with ElectricityGold Refining EquipmentOperations and ProductsCopper RefiningProcess for the Electrolytic Refining of CopperMint Processes The refinery takes the bullion purchased by the receiving department, and carrying more than 200 parts of precious metals in 1,000, or, in mint parlance, over 200 fine, and separates and refines
Solubility Of Gold In Mercury
Although three rather extensive researches on the system gold-mercury have been published within the last ten years, the disagreement in the various results is most remarkable, particularly at lower temperatures. Quite recently rather precise results on the system silver-mercury, using a new type of solubility tube, have been published by Sunier and Hess;* it has therefore been thought advisable to
How Collector Affects Flotation
It appears from all tests run to date that under otherwise constant conditions, increasing the concentration of a given collector increases R and decreases K in a uniform manner. This appears to be true for all collector types and is supported, e.g. by the data of Tables III and IV as well as Figure VIII from reference. This observation has
Heap Leaching Silver
Table of ContentsLoading the HeapPregnant Solution PondsPlant OperationTypical Operating Data Leach Pad Construction: After the site of this Silver Heap Leaching pad was prepared, a pad base consisting of about 15 inches of mill slimes or a fine bentonitic clay from an old nearby tailings pond was laid down. The pad was constructed slightly larger than the dimensions of the heap to
Underground Tunneling
Table of ContentsModern Alpine TunnelsThe Simplon TunnelPowerVentilationRock-TemperatureIlluminationDrainageTransportationMethod of ConstructionDrillingExplosivesMuckingGeological ConditionsRate of ProgressThe Loetschberg tunnelGeological ConditionsRock-TemperatureRate of ProgressPowerTransportationLightingDrainageThe Drill-CarriageExplosivesExcavationVentilationRock Temperature It is now generally admitted by experts that at least so far as rapid progress is concerned the Alpine system of tunnel-driving is superior to any other. This is perhaps natural in view of the record of experience in driving tunnels
Ammolite
Ammonite is an iridescent gem formed within an ancient marine fossil for which it was named—ammonite. Originally discovered by the Blackfoot Indians, ammolite is mined only in Southern Alberta, Canada. Most ammolite is assembled into doublets or triplets to increase durability because solid ammolite is usually thin and fragile, If it’s untreated and solid, ammolite is usually priced per carat and shaped as a freeform