Blogs
Clarified Solutions by Reversible Cake Filtration
Table of ContentsReversible Cake FiltrationApplications In order to filter small amounts of fine slimy solids the reversible cake filtration process was developed. The filterable solids concentration in feeds can range from less than 1 ppm up to about 5%. The relative advantages of this process are usually the greatest in the range of.0.05% to 1.0% filterable solids. Filterable solids that
Bucket Wheel for Open Cast Mining
Table of ContentsWheel Excavator DesignControl CabOperation In deep strip mines the job of moving overburden may be so much bigger and more costly than the removal of coal or ore that the operation is often called dirt mining. Constant improvement in stripping machines and techniques of using them is needed to offset rising costs and to increase production in mines
Automatic Sampling at Dumping Points
Table of ContentsTest ProcedureComparison of ResultsDiscussion of Results One of the major problems in the purchase and sale of coal shipped in lake or ocean going vessels has always been, the difficulty in obtaining a true analysis of the shipped coal’s quality because of faulty sampling by manual methods. As long as coal was sampled according to standards set up
Undercut and Fill Mining
Table of ContentsGeneral Description of the MethodTimberingOre RemovalDrilling and Blasting Undercut-and-fill- mining is a method developed by the International Nickel Company to deal with abnormal-pillar mining conditions at one of its mines. Results have been such -that its use has been extended to normal pillar recovery operations in other mines of the Company as a replacement for conventional square-set pillar
Double Stage Filtration Circuit & Wash Thickener
Table of ContentsThe CircuitModified Circuit The operation of a series wash thickener-two stage filtration circuit determines the soluble loss in many hydrometallurgical operations. A study of this circuit yielded expressions which permit calculation of soluble loss for almost any condition of operation. The soluble loss over a range of the circuit variables is presented to illustrate and evaluate circuit performance.
Acid Leaching of Uranium
Compared to the uranium ores in Colorado Plateau and New Mexico, the uranium-bearing lignites in North and South Dakota are relatively difficult to process. This is due chiefly to the irregular mineralization of the lignites, and partly to the non-uniform distribution of uranium within the deposits. The three lignite samples used in this investigation were collected from Harding County, South
How to use Bond Work Index to Measure Operating Comminution Efficiency
Comminution efficiency can be expressed in three different ways. Theoretical Efficiency: actual energy consumed, in a comminution machine compared to the theoretical energy required to make the size reduction. Operating Efficiency: compares the operating work index, calculated from production comminution machinery operating data, to the Bond Work Index from bench scale comminution tests or calculated from pilot plant operating data.
Effect of Feed Size in Comminution
The feed size cannot be neglected in any case where the effective size modulus of the feed is not too much coarser than the size modulus of the product. This can be illustrated in the second experiment of Fuerstenau and Cohen where the feed is considered to be the original -6 +8-mesh material. However, one can also consider the product
Single Impact Testing of Grains of Brittle Materials
Table of ContentsImpact Test, Machine and Testing ProcedureExperiments on Identical SamplesExperiments on Materials with Variable Parameters A method and equipment have been developed for measuring the impact strength of grains of brittle materials. It is shown that brittle materials develop a characteristic particle size distribution when fractured by impact. A simple mathematical model has been found to describe this distribution, and
Rotary Percussion Rock Drilling
“Rotary percussion” implies two types of energy, rotary and percussion. Into these categories fall rock drills of varying sizes. The larger ones drill above 6″ diameter holes; the medium size, 2 ¾-” to 4 ½” holes; and the smallest, 1 ¼” to 2″ holes. Essentially, the larger holes are drilled with down-the-hole drills using tri-cone bits. Percussion energy evolves from
Ropes for Drum and Koepe Friction Hoists
Table of ContentsGeneral Characteristics of Six-Stranded RopesHoistsFactors of Safety and Bending Ratio RelationshipsDrum to Hope Diameter Ratio Four basic designs of ropes are now employed for hoisting duties: Six-strand, round strand ropes with fibre cores. Six-strand, triangular strand ropes with fibre cores. Non-rotating, multi-strand ropes. Locked coil ropes. Very solid and reliable ropes can be obtained with this simple geometric
Reagent Testing – How to Analyse Results by Statistics
In the operation of today’s large scale ore-processing mills, it is extremely important to have some way of making an objective evaluation of the performance of the available flotation reagents. While Reagent Testing the use of Statistics is necessary for Result Analysis. Attempts to do this may often result in inconclusive findings since the magnitude of the difference in the
Expansible Shale Prospecting
Field criteria are needed to help the prospector recognize a potentially expansible shale, clay, or slate. Certain criteria have proven useful in California even though the physical-chemical mechanisms of expansion are not. thoroughly understood. Three conditions must be satisfied before expansion can take place. The raw material must partially fuse at a low temperature (1800-2000°F.). Concurrently a gas must form.
Particle Size Reduction with Roller Mill
Table of ContentsRaymond Roller Mill Grinding PrincipleRange of Materials PulverizedSimultaneous Drying and Grinding For reasons well known to Mining Engineers, fine grinding in the wet form is quite universal in plants engaged in the extraction of metallic values from crude ores. In the processing of non-metallic and industrial minerals, however, fine grinding in dry form is the more common method.
Factors Affecting the Angle of Slope in Open-Cast Mines
Table of ContentsThe Relation Between Economy of Operation and Slope Angles in Open-Pit MiningSafety of Slopes of PitsGeological Factors Affecting the Pit SlopesThe Soil Mechanics ApproachThe Difficulties of the Soil Mechanics ApproachThe Rock Mechanics Approach The problems of slope stability in open-cast mines are examined. A criterion, the instantaneous stripping ratio, is suggested for use in the design of pit
Low Alkali Portland Cement
Table of ContentsThe Alkali-Aggregate ProblemThe Influence of Dust Collection SystemsWet Process Leaching SystemsDry Process Leaching SystemsKiln Conditions and Their Effect on Dust Leaching The concurrent observation of the phenomena of alkali-aggregate reaction and development of efficient dust collection systems on rotary-kilns made mandatory the process modifications to produce low alkali cements. Such low alkali cements as were available prior to
Cultured Quartz
The technique of growing crystals from the melt, such as KI, NaBr, was already commercially in use. Quartz could not be so grown, since its utility depends on the form stable below 573° C, and, even if it could be grown from an extraordinarily viscous melt, the higher form passing through this transition becomes twinned. Again, several crystals were being
Clinkering Process in Portland Cement Manufacturing
In portland cement manufacturing, the raw materials are changed to clinker in the burning operation. Generally the rotary kiln is used for this purpose and involves many processes including pelletizing and nodulizing. This transformation is called clinkering and is analyzed as now generally practiced in cement making from the raw material to the resulting clinker. Cement manufacturing may be divided
Kaolin Bleaching Process
A process for producing reductive bleach in-situ in kaolin slurries has been developed. The bleach is formed by mixing an iron sponge powder (-325M) with slurry treated with SO2. The process has been successfully demonstrated in production, and applied to several grades. The color, brightness, and viscosity of the bleached product is equivalent to or better than that of product
Automatic Hydraulic Takeups for Belt Conveyors
Since the majority of mines were then using direct current power systems, we were able to use controllers with 3 or more steps of starting resistance. The slow belt speeds coupled with relatively long starting cycles kept the rate of acceleration low and gave us smooth, easy starts. The conveyor belts in common use were usually rather thick; they were
Ammonium Nitrate Blasting Agents
The situation of The Consolidated Mining and Smelting Company of Canada Limited, or Cominco, may be somewhat unique in that the Company is not only a manufacturer of ammonium nitrate, but as a mining company is a major user of its own product. This situation has resulted in highly successful application of ammonium nitrate-oil explosives. Several noteworthy techniques have been
Seismic Refraction Equipment
Within recent years portable seismic refraction units have found their place in the industry for shallow investigations. Completely portable, relatively inexpensive and of proven accuracy, the portable refraction seismograph is an electronic tool in an electronic age. The seismic refraction theory is based on the ability of various materials to transfer shock waves at different velocities, depending upon their elastic
Remote Control of Longwall Operations
Table of ContentsThe SupportsAdjacent Chock ControlBank Control working in one DirectionR.O.L.FApplication It is truly remarkable how the image of longwall as a method of mining has changed. Today the world looks on longwall in the hope that it can produce the next really big break through in productivity. Three correlated machinery developments have made this possible, but it is not
Fly Ash Properties and Beneficiation Methods
Fly ash is extremely variable and heterogeneous in all respects except its fine size. Because of its production in huge quantities, it becomes significant as a potential raw material. Fly ash is a finely-divided, widely variable, heterogeneous material most of which is formed by the solidification of molten droplets of inorganic substances in the cooler portions of a furnace fired