Blogs
Diastrophic Theory
Table of ContentsThe Anticlinal TheoryThe Hydraulic TheoryThe Diastrophic TheoryRock PressureHow Capillary Pressure Seals an Oil Pool The writer has devoted a number of years to practical operations and to the study of geology in the oil fields. In consequence, he has been brought to investigate the theories advanced to account for the accumulation of oil and gas in commercial deposits.
Conveyor Belt Calculating Chart
The accompanying chart has been drawn for the convenience of engineers as a means of quickly determining the correct number of plies of conveyor belts operating under specific conditions. The calculations are based on the average safe strength (factor of safety, 15) of the various standard rubber conveyor belts. The calculations assume maximum loading conditions; that is, the belt is
Casting Metal Rods
In view of the circumstance that very few important changes have been made within the last 15 or 20 years in the equipment of rod and wire mills, the description of a new process introduced by Grenville Mellen, of Llewellyn Park, N. J., to take the place of the present laborious system of producing rods of lead, zinc, brass, copper,
Ore Dressing Methods
Table of ContentsGold Ore ProcessingTypes of Gold OresMethods of Ore TreatmentAmalgamationConcentrationCyanidationGold-Milling Data In this bulletin the subject of ore dressing is approached from the economic rather than from the technological standpoint, and the supporting data have been compiled with a view to their bearing upon the economic exploitation of ore deposits. Results obtained are stressed rather than the details of
Hardinge Conical Mill Capacity
The following conclusions on the work of the Hardinge mill are based on data furnished to the writer by the Hardinge Conical Mill Co. in the form of the mesh cards hereto appended. Energy units (E. U.) and relative mechanical efficiencies (R. M. E.) are computed by the “volume method” of Stadler. Screen apertures used are the average apertures of
Oxidizing Roast; Stibnite the Antimony Mineral
The leading antimony mineral is stibnite. In smelting stibnite ore two processes are available, precipitation and roasting-reduction. The former is suited, only for high-grade ores. As low-grade ores are more common than high-grade, roasting-reduction is of greater importance than precipitation. In the roasting process the aim may be to leave the oxidized antimony in the ore, or it may be
Smelting of Lead Ores using High Lime Slags
Anton Eilers, who was then interested in the lead smelting and refining business near Salt Lake City, Utah, made a somewhat radical departure from the regular practice at that time, which was to use but little lime in the slag, with a high percentage of iron. Lime was not only a cheaper flux than iron, but it enabled the metallurgist
Open-Pit Mining Methods
Open-pit mining methods are applicable to mining ore deposits that apex at or near the surface. If the deposit apexes below the surface, the overburden and barren capping overlying the ore must be removed in advance of open-pit mining. The removal of this material is known as stripping. The stripping-pit limits must be extended beyond the limits of the ore
Conveyor Stacker Controls
Stacker control devices can range from minimal stockpile level sensors to quite complex control systems depending on the desired degree of automation. For the simple fixed stacker, a basic stockpile level sensor to prevent the stockpile from getting too high is often the only stacking control required. This level sensor can be just a simple tilt switch connected to the
Zinc Dust Precipitation Tests
Table of ContentsImpurities in Zinc DustZinc OxideMetallic ImpuritiesOther ImpuritiesScreen Analyses of Zinc DustSubstitutes for Zinc DustConclusions The use of zinc dust for precipitating the precious metals from cyanide solutions is well established now in many places, and has many advantages over the shavings method of precipitation. Although much work has been done on methods of testing zinc dust, as yet
Hoisting Ore in Mining
Table of ContentsAuxiliaries Actuated by Oil under 135 lb. PressurePressure on Low-pressure Cylinder Automatically RegulatedCondenser Operates under Severe ConditionsHoisting Speed 1,300 to 1,600 ft. per MinuteRound Rope on Grooved Drums Now UsedUnderground Storage Bins Have Loading HoppersOre Loaded into Railroad Cars by Belt Conveyors and TrippersIncrease in Underground Storage Capacity ContemplatedCompressed-Air Hoists for Men and Timber at Most ShaftsAir Stored
Ore Tramming in Mining
Table of ContentsOld Haulage System UnsatisfactoryNew Plan Included Electric Haulage and Central HoistingElectric Haulage on Alternate Levels OnlyTrack is 20-in. GaugeDirect Current at 250 Volts Used UndergroundFactors Affecting the Choice of CarsSeveral Types of Cars UsedThree to 7-Ton Electric Locomotives in UseStorage-Battery Locomotive TriedSeveral Designs for Stope and Transfer ChutesSacramento Selected for Hoisting Shaft The ore deposits of the Warren
Maintenance Policy & Procedure
Maintenance Policy Area Level 1 (basic) Level 2 (controlling) Level 3 (improving) Level 4 (best) 2.1 MAINTENANCE MANAGEMENT LEADERSHIP 2.1.1 Maintenance Mission No mission Mission developed and understood by management Mission developed and understood by management & supervision Mission developed, understood and articulated by management, supervision, maintenance team personnel & support personnel 2.1.2 Maintenance Vision
Stamp Mill Cam
The cams at present universally used in stamp mills lift the tappets with an involute form of curve, to which the surface of the tappet is always tangent; moreover, the line of contact between tappet and cam, if produced, would pass through the center of the stem. This is no doubt a desirable feature, but the writer has long believed
Quicksilver Ore Mining & Reduction Method
Table of ContentsReductionChargingReinforcement of TilingChange in FiringCondenser PlantCosts and Profits The low cost of mining was the principal consideration, since, with mercury’s price per pound, the total gross value of the ore did not exceed too much per ton. Square setting and filling was out of the question, so various attempts with cheap methods were made, among them a shrinkage system. None
Sound Steel Ingots
Last year this Institute was good enough to accept some remarks by the writer regarding sound steel, entitled Plant for Hadfield Method of Producing Sound Steel Ingots, being a continuation of a research in which for some time the writer has been engaged, and full particulars of which were submitted in papers entitled A New Method of Revealing Segregation in
Rotary Rock Drill
In drilling for water and oil to reasonable depths through the generally soft yielding clay and sand formation of the Coastal Plain of Texas, Louisiana, and Mississippi, the rotating method of drilling was adopted, principally on account of the easy and quick penetration, and the low cost of the drilling plant. In favorable ground, free of heavy gravel and rock
CWi vs DWi
What is the difference between CWi and DWi: WiC measures fracture strength in coarse rocks, DWi measures matrix competence in medium-size rocks.
Mine Ventilation EXAMPLE
Table of Contentsmine shaftsConditions under Natural VentilationSeveral Mine Fires OccurredGeneral Working Conditions InvestigatedPressure and Exhaust Systems Reasons for Adopting Pressure SystemEquipment and General Arrangement for Mechanical VentilationCombined Natural and Mechanical SystemLower Temperature and Relative HumidityVelocity and Volume of Air IncreasedLowell and Sacramento Divisions Ventilated JointlyData Collected before Mechanical Ventilation System PlannedTwo Standards of MeasurementAverages Plotted on the Mine MapAmount of Air Necessary for Each District CalculatedNatural
Cost of Stoping for Underground Mining
Stoping cost is one of the largest of the items comprising the total cost of producing ore. The cost per ton of ore mined is important but may be overemphasized if the more important cost, that per unit of metal recovered, is thereby overlooked. A given stoping method may give a low cost per ton of ore but, by reason
Ore Dilution & Recovery in Mining
Table of ContentsRate of ExtractionEffect on Recovery in Ore-Dressing Plant Recovery and dilution usually are interrelated; with some methods of stoping a high recovery involves contamination of the ore from the walls or capping, and often clean ore can be obtained only by leaving some ore in the mine. In open-stope mines the greatest loss of ore is that tied
Mine Roof Stresses & Support
The stresses, in the simplest structures are often those we find most difficult to analyze. The most complex condition in mine stresses is found in simple tunnels where the roof, the sides, and the floor are a monolith. The functions of the parts are like the parts themselves not distinct and specialized, and the problems to be solved are like
Compare Stoping Methods of Mining
Table of ContentsFlexibilityPreparatory DevelopmentPercent Recovery of Ore and DilutionCost of Stoping The foregoing descriptions and discussion of the different stoping methods and practices and the accompanying tabulated data indicate the conditions under which they may be applied and serve as a basis for comparing them. Stoping costs will be presented later. Direct comparisons of the different methods are difficult because
Costs of Mining Methods
Table of ContentsCosts of Drilling and BlastingComparison of Stoping MethodsUnderground Mine LightingTimbering and Handling Ore in StopesSquare-Set vs. Top-Slicing MethodsHow Much does Tramming CostCost Breakdown of Tramming To compare properly two different methods of mining, it is not wise to attempt to calculate the total cost of each, but rather to compare the costs of those operations that are differently