In the examination of an undeveloped prospect a decision must be arrived at from an inspection of the outcrops and the exposures in a few shallow pits. Prospects that are offered for sale rarely expose any important quantity of good ore, work having usually been stopped when the immediate exploration no longer yielded favorable results. … Read more

Diamond Drilling

Table of ContentsDiamond DrillsDiamondsUses of the Diamond DrillSupervisionPreparing a Prospect for Diamond DrillingControl of the Location of Drill HolesContracting the DrillingForm of ContractTesting Drill Holes for Vertical Angle and AzimuthWedging Drill Holes to keep them Nearly VerticalCementation of Drill HolesNew Standard Sizes of FittingsSludge CollectionCore and how to Handle itSampling and Classification of CoreCore Samples … Read more


Table of ContentsGenesis of a Typical Porphyry DepositNew CorneliaChuquicamataBraden Frequently the careful engineer puts the word porphyry in quotation marks or precedes it with “so-called,” when he writes of the Porphyry Copper mines. This is done by way of serving notice that he is aware that the term is not a precise one, though no … Read more

Metallurgy Problems

While reflecting on the subject of my present paper, I soon realized that it would be very difficult to say something really new about any special aspects of metallurgy. In consideration of the excellent scientific work that has been done in the United States in connection with almost all the fundamental questions that are of … Read more

Gold Alloy Melting and Casting

Table of ContentsMetals used in AlloyingGas and Electric MeltingDefects in IngotsSurface DefectsIngot ProportionsPorous IngotsDeoxidizersUse of Deoxidizers in Sterling SilverUse of Phosphorus in Gold AlloysCalcium Boride in Gold AlloysCasting TemperatureEffect of ImpuritiesSulfur in White Gold The problem of scrap is probably of greater importance in the production of gold, silver and other precious metal alloys than … Read more

Method for Estimating the Efficiency of Pulverizers

Table of ContentsImpact Grindability TestGrindability Test in Analysis of Mill PerformanceGeneral Discussion Grinding costs are an important item in cement manufacture, and the cost of power is one of the large items in grinding costs. Even where power is of secondary importance, cost items dependent on mill capacity are influenced by the efficiency with which … Read more

Screw Crusher

The Freeport Sulphur Co. built a portable crusher in 1944 that solved a problem that none of the crusher manufacturing companies contacted were able to do. Two of these crushers have now been in service for 6 years, giving satisfactory service in handling a million tons per year, and having a capacity of over 2000 … Read more

Hardness and Toughness of Rocks

The speed of drilling rock has become an important factor in mining operations, while the placement of holes, kind, and quantity of explosive used are equally important. These are a function of the rock hardness and toughness. Both of these factors must be considered in compiling a table that will enable a mine operator or … Read more


Table of ContentsConcasseurs PrimairesConcasseurs a MachoiresConcasseurs GiratoiresComparer Concasseurs PrimairesConcasseurs SecondairesConcasseurs a ConeTypes de Concasseurs de PierreCircuits de Concassage Le concassage constitue la premiere etape de la comminution. Son objectif n’est pas la liberation des mineraux, mais simplement la reduction de dimension afin de faciliter la manipulation ulterieure du minerai. II est normalement fait a sec … Read more