Blogs
Microscope in Mining Engineering
The valuable results that have followed the application in recent years of microscopic methods of research to problems of ore genesis have been significant, but possibly the recognition of their practical importance is not as general as might be, and while, as a scientific method of investigating ores and rocks, the advantage derived through the use of the microscope is
Tunnel Construction Cost
Table of ContentsTunnelSummary of CostsDiscussion The Rawley property is located in the Kerber Creek mining-district, Saguache county, Colorado, at an elevation of 10,600 ft. (See sketch-map, Fig. 1.) Ore was found in this vicinity, and claims covering a large area were located and in many instances patented. The ores, however, being of comparatively low grade, and the nearest railway station,
Sampling Ore from Hammer Drills
The use of hammer drills for obtaining samples in underground work has increased in recent years. This method has advantages where holes are short, ground conditions preclude the use of diamond drills, satisfactory core recovery is impossible, or sludge samples are accurate enough for the purpose in view. Holes may be drilled at all angles from horizontal to vertical, up
Drill Core Sampling
The advantages of obtaining core samples that provide a visual record of the rocks and ores sampled and at the same time furnish samples for assay have been pointed out under the caption Exploration by Drilling. The diamond drill, which employs either carbons or bort as cutting media, has been the type of core drill most widely employed in metal
Grab Sampling in Mining & Drilling
Grab sampling usually consists in taking portions of ore at random from muck piles, chutes, or the tops of cars of ore. When done in this manner it is a haphazard method that can be relied upon only for roughly approximating the grade of the ore and often is employed merely for that purpose. The human factor or tendency to
Ore “Rock” Face Sampling
Face sampling is the cutting of pieces of ore and rock from exposed faces of ore and waste. The faces may be natural outcrops or faces exposed in surface trenches and pits or in the backs, walls, and floors of development openings and stopes. Face samples may be taken: by cutting grooves or channels of uniform width and depth across
How to Subsample a Large Bulk Sample or Soil, Ore, or Rocks
Before assaying, original samples must be cut down, often in several stages. Each cut involves, in effect, the sampling of a sample, the final portion comprising only the ore that actually goes into the crucible or flask and upon which the actual determinations are made. In cutting down samples to reduce the bulk to the final amount required for assay,
Pig Iron Manufacturing Process
Table of ContentsElectric Furnace Production of Pig SteelMaking Pig Iron by Electric FurnaceRegulation of CarbonPig Iron ImpuritiesLoss of Iron in the SlagAdaptability of the Process to Continuous OperationCost of Production of Pig IronPig Iron At the beginning of the use of the electric furnace, for the manufacture of calcium carbide and ferro-alloys, experimental work was conducted in it upon the production of
How Much is the Cost of Mining Exploration
Table of ContentsNorthern CanadaArizona In the preceding pages some unit costs of sinking, drifting, cross-cutting, and drilling have been presented, together with a few costs covering entire churn-drilling campaigns. Few figures are available covering the total cost of exploring a property before reaching a decision to develop it for production. However, figures are available covering expenditures for exploration and development
Exploration Drilling
Drilling is employed extensively, either as the principal exploratory method or to supplement exploration by underground and surface workings. Three principal types of drills are employed for this purpose—churn drills, core drills, and hammer drills. In ground too soft to core and in which a churn drill would stick, a rotary drill with a fish-tail bit is useful for obtaining
Prospecting Lode Gold Deposits
Prospecting for lode deposits begins with a search for mineralized outcrops, the key to the existence of which may often be found in mineralized float (pieces of rock from the lode that have been loosened by weathering and washed downhill). Geologists now generally agree that most valuable mineral deposits have a magmatic origin and, therefore, that the most promising areas
Prospecting Placer Gold Deposits
Table of ContentsPlacer MiningGeneral Geology of Placer-Gold DepositsCharacteristics of Placer Gold Prospecting for placer gold, except perhaps in the case of buried placers, is the simplest form of prospecting. Gold, platinum, and tin are the principal metallic minerals won from placers, but gold (alloyed with varying percentages of silver) is the only metal that has been recovered in commercially important
Exploration Drill Sampling Techniques
Table of ContentsDrill SamplingAccuracy Of Churn-Drill SamplesSampling With Core DrillsSampling with Hammer DrillsFace SamplingGrab SamplingCutting Down SamplesSummary Of Sampling A brief summary of the methods employed and the costs of prospecting and exploration has been presented in the preceding pages. The primary object of such work, as already stated, is to find ore and furnish information upon which to base estimates
Methods of Mining Metals
Table of ContentsMining DefinitionsProspecting & ExplorationProspectingEquipmentMining LawsPlacer DepositsLode DepositsReporting On ProspectsExplorationExploratory WorkingsExploration By DrillingCost of ExplorationExploration Drill Sampling Techniques This report summarizes mining practices of a large number of metal mines in the United States and foreign countries. The adaptation of mining methods best suited to the various natural conditions in mines is discussed, and comparative costs are presented. The basic
Agitation Leaching in Parral Tank System
Table of ContentsMeans of Effecting AgitationAnalysis of the Pachuca Tank and Its OperationsDefects of the SystemThe Parral-Tank System of Slime-AgitationExtraction of ValuesConclusion Of the treatment of the slime-pulp of gold- and silver-ores by cyanidation, agitation is an essential part. When prepared for treatment, this pulp, consisting of ore reduced to such fineness that approximately 80 per cent, of it will
Spectrochemical Determination of Beryllium
Table of ContentsBeryllium AlloysOutline Beryllium Assay MethodsFusion-Pellet-Spark MethodSustaining Alternating-Current Arc MethodEquipmentStandardsExperimentalBorates in GlassProceduresFusion-Pellet-Spark MethodSample and Standards PreparationExcitation, Exposure, and Development ConditionsPhotometrySustaining Alternating-Current Arc MethodSample & Standards PreparationSample Excitation, Exposure, and Development ConditionsPhotometryAnalytical ResultsDiscussion and Conclusions Spectrochemical methods were developed to determine beryllium in the concentration range 0.0015 to 4.0 percent in siliceous mineral beneficiation products. Two methods are described. They are (1) a fusion-pellet-spark
Determination of Beryllium by Fluorometric Method
Table of ContentsAssay Determination of BerylliumAcknowledgementsReagents & EquipmentBeryllium Assay ProcedureBorates in GlassExperimental Results And DiscussionInterfering IonsFactors Affecting Morin-Beryllium Fluorescence A fluorometric method using morin in an alkaline-buffered chelating solution has been developed by the Bureau of Mines for determining beryllium in ores and mill products. Apparatus for measuring fluorescence intensities of the beryllium-morin reaction is described. Preparation of the sample for
Oil Burning Systems of Liquid Fuels
Oil burners, oil furnaces, and methods of installation, have been the subject of many articles, but information concerning oil-burning systems, based upon scientific principles, is still in great demand, especially in the manufacturing districts of our country. Fuel oil, as it is termed (this being the residuum from oil refineries), has for many years been of great service to our
Mining Massive Porphyry Copper Deposits
Table of ContentsUtah Copper and Boston Consolidated MinesRay Consolidated MineMiami MineInspiration MineOhio Copper MineMine Development The past decade has witnessed the development and successful operation of a half dozen or more immense deposits of low-grade copper ore that occur in the Western States. In every case sufficient capital was available to carry out the development of the mines in the
Types of Underground Mining Method Comparison
Table of ContentsFactors Affecting Choice of MethodReview of Stoping MethodsUnderhand Stoping Mining MethodOverhand Stoping MethodLongitudinal Back, Flat-Back Mining MethodLong-Wall StopingmMining MethodRill-Cut Stoping MiningSaw-Tooth Back StopingShrinkage StopingMining by Combination StopingSide StopingBreast StopingSublevel StopingSquare-Set StopingFilling MethodsCaving Methods of MiningTop SlicingSublevel CavingBlock CavingBack Caving into ChutesCosts of Mining Methods In any discussion of Methods of Underground Mining Comparison, one is repeatedly confronted with the difficulty of dealing with so
Timber Support in Underground Mining
Table of ContentsApplication Of Rock BoltsBolting patternsBeams and roof tiesAnchorage capacity and bolt loadingProblems of bolt useAdvantages of roof boltsInstallation sequenceUsing Steel Timber Set Underground Support Use Of Concrete SetsDesign Of Concrete SetsOrdinary setLoaded drift set — capSpreader BearingBond, Shear, and Stirrup SpacingCalculation of concrete mixPlacing sets in driftChute setsSide laggingWooden HeadframesWooden Ore Bin When selecting a square-set design, one should adopt
Underground Mine Timbering & Support
Table of ContentsTimberingEstimation of Ground Pressure with Selection of SupportTimber Cap SelectionSelection of Standing PostsPost in bendingForce acting on spreaderSuggested Change in Working StressTreatment Of TimberFraming Of TimberInstallation Of TimberTimber RepairingDiscussion Of IllustrationsSimple Drift SupportsHeadboardsSqueeze SetsErection Of Drift SetsChute ConstructionShaft Bearing SetsCribbingApplication Of StullsLoose Or Squeezing GroundVertical And Inclined ShaftsSquare-Set Timbering No matter how limited their extent, few underground mining operations
Free and Hindered Settling
Table of ContentsFree and Hindered SettlingThe ConstrictionPermissible DensitySize of Constriction OpeningDesign of Classifier TopMethod of Designing a ClassifierSize of SpigotArea of Constriction OpeningSize of Sorting ColumnArea of Classifier Top In his paper entitled, Development of Hindered-Settling Apparatus, Dr. Richards has related the history of the development of the hindered-settling classifier and given illustrations of the several types of this apparatus