Search Documents

By L. C. IlsLey

The increasing use of Diesel engines for operating equipment on trunk-line railroads and for power-plant units has stimulated interest in the use of Diesel engines for other lines of work, among which is the possibility of substituting Diesel locomotives for trolley locomotives for mines. The possibility of developing Diesel locomotives for duty in American mines is not as remote as it might seem, particularly in view of the fact that locomotives of this type are already used in considerable numbers in European mines. A study of Diesel locomotives in Europe is contained in Report of Investigations 3320, Diesel Mine Locomotives - Development and Use in European Coal Mines, by George S. Rice and F. E. Harris.

Jan 1, 1938

By Peter Greenhalgh, W. Baguley, R. P. Riley

The traditional impeller system for aeration and suspension of slurries, e.g., in bacterial oxidation plants, is the vertical flat blade turbine (VFBT) . This type of impeller is energy-intensive, which results in a heavy-duty design of shaft, gearbox and drive. The VELMIX bio-reactor development programme is designed to evaluate the use of the new generation of hydrofoil impellers which consume less power and thus have poten­tial for capital and operating cost savings as well as being possibly less damaging to the bacteria. The early tests on pyrite oxidation in a 300 litre laboratory pilot tank using the Thiobacillus ferro oxidans bacteria, showed that hydrofoil impellers had superior charc­teristics to the VFBT impeller and to air­ agitated pachucas, with lower energy input. The geometry of the sparge _ring was found to be very important in optimizing the system.

Jan 1, 1990

By P Jackson, J Rea, M D. Goodz

The Morning Star Gold Mine has operated over a 101-year period, producing gold from narrow quartz veins and sulfide stockworks hosted mainly within a dioritic-gabbroic dyke. The deposit has been developed over a vertical depth of 980 m with drilling extending the vertical depth to greater than 1200 m. Currently there is a total Inferred Resource of 4.6 million tonnes at a grade of 6 g/t for 910 000 ounces of contained gold resources, which comprises an underground project and a surface project. Significant variation exists between the grade of drill core intersections and that observed in face sampling and subsequent production reconciliation (250 - 650 per cent). Studies were carried out on ten major production reefs, where the grades of drill intercepts were compared with face samples collected during development and mining. The implications of this study have been used as justification to assign production or stope/development grades where applicable to resources that are direct extensions of the historical development headings. Grade assignment and its impact on sensitivity for gold resources are detailed and show a 40 per cent variation in the gold resource, depending upon whether a production or calculated stope grade is used in grade assignment for the major reef deposits. Recent diamond drilling has intersected approximately 40 new gold bearing quartz reefs and sulfide zones that contain all the key mineralogical and structural indicators, and traditional large variations in gold grades similar to the historical major production zones. The implications of grade factoring and grade assignment are the greatest challenges confronting the resource estimation team in defining grade for these new zones. Grade assignment is seen as a method of balancing known historical production observations with the irregular grade distribution inferred from drill core assay results. Ongoing mine development and bulk sampling works are planned to validate the grade assignment process. The first stage of this process is the trial mining of the newly discovered Maxwell Reef (MR). The stope drawpoints were completed in August 2008 and the MRS1 stope is scheduled for completion in September. The stope reconciliation results will be presented at the October 2008 conference.

Jan 1, 2008

By Ray Jambakhsh, John Okell, Frank Cook

"In early 1988, an experimental study was carried out at the Inco's McCreedy West Mine inLevack, Ontario. The objective was to develop blasting techniques which would allow themine to maintain production targets and reduce blast induced vibrations and overpressure.Due to its close proximity to the town of Levack (approximately 900 feet), particularconcern was expressed as to the vibration and overpressure resulting from the undergroundblasting operations."

Jan 1, 1993

By A. Prokopiev

The biological stage of reclamation is the third final stage in remediation the damaged mining terrains, which is carried out following the completion of the mining technical stage. The biological stage of reclamation is carried out through restoration of the vegetation layer. The biological reclamation includes all activities related to the introduction into the terrain of vegetation, microorganisms, insects, and animals, with the acceleration of the succession and creating conditions for a sustainable ecosystem close to the natural one. It comprises of all anti erosion and other activities such as the preparation of the land for growing agricultural crops, sowing grass seeds, planting seedlings, amelioration of the soil and further care for the vegetation until its final place on the land. Mineral and organic-mineral ameliorants for biological reclamation were studied. The basic mineral ameliorant is Bulgarian natural zeolites. The zeolitic-rich tuff samples provided from Golobradovo deposit was characterized by their chemical and mineralogical composition and ion exchange properties and X ray analysis. The average content of clinoptilolite was found to be more than 80%. The materials had ion exchange capacity (NH4+) varying from 100 to 110 meq/100g. Chemical modifications of natural clinoptilolites were made in order to form active phases of nitrogen, phosphorus, potassium, and microelements. Slow-acting mineral ameliorant was developed. Organic-zeolite substrate for biological reclamation was developed. This new product is a mechanical mixture of organo-matter and modified zeolites. Agro-chemical parameters of new ameliorants were determined. The substrates including studied overburden dump soil and mineral or organo-mineral ameliorants are produced. The grass growth test was performed. Keywords: biological reclamation, ameliorants, damaged mining terrains

Sep 1, 2012

By T. F. Mitchell, Walter J. Long

"SUMMARYThis report is one of a series giving results of laboratory and pilot-plant investigations of the concentration of western manganese ores begun in December 1940. Data given summarize results of laboratory investigation of three samples of complex oxide manganese ores from the Madeline property, Lake View, and Victory claims, Clallam County (Olympic Peninsula), Wash. The samples represented an extremely intimate and complex association of manga¬nese oxide minerals with silica and iron.Owing to the complex nature of the ores, no effective concentration by ore-dressing methods was possible. No high-grade manganese concentrates were produced and the highest recovery at minimum accountable grade was only 55 percent on one of the ores tested.Since the Clallem County ores did not respond to ore-dressing methods, leaching processes were investigated, results of which are to be published in a separate report.INTRODUCTIONOre-beneficiation tests were conducted on three samples of manganese oxide ere from the Madeline, Lakeview, and Victory claims, Clallam County, Wash. The ores are extremely complex because of the unusually small size of manganese mineral particles, their mode of occurrence, and relationship to the gangue. None of the three ores was amenable to the production of high-grade manganese products by ore-dressing methods."

Dec 1, 1945

By R W. Henley, L Knuefing, M Turner, Y Zhang, M Saadatfar, A Limaye, R Cruikshank, M A. Knackstedt, A Kingston, L Beeching, N Francois

A better understanding of ore fragmentation and the textural features of ore is a key to the energy efficient extraction of targeted minerals from low-grade ore deposits. In this study, X-ray microcomputed tomography (micro-CT) is employed to study mineral liberation during the tensile failure and onset of fragmentation of a copper ore. Our results show that X-ray micro-CT could inform new studies of ore micromechanics and fragmentation at the laboratory scale and may offer new avenues to address current challenges in the design of efficient comminution processes. We present the results of experiments based on a high-pressure apparatus enabling micromechanical studies to be carried out in situ (inside a micro-CT scanner). This platform produces high-quality 3D images of the evolution of a sample of porphyry copper ore during an in situ fragmentation test. A sequence of tomographic images enables mapping in 3D of both the deformation of mineral phases and the fragmentation process. The fragmentation occurs quasistatically through multiple stages starting with an initial tensile fracture splitting the ore diametrically, followed by tensile-activated nucleation and growth of multiple fractures producing a complex fracture network. Coupling breakage with microstructural information enables quantitative determination of the impact of ore texture heterogeneity on fracture patterns and mineral liberation. This microstructural information can be compared to key measurements of the ore mechanical behaviour such as the global deformation energy, strain deformation field and the stress relaxation response. The latter allows one to identify interesting precursor signals of the tensile failure. The copper liberation, fragment size distribution and breakage patterns are statistically characterised and related to comminution mechanisms which are clearly identified in the sequence of tomographic images. The two dominant mechanisms are rock-rock friction/compression induced by fracture closing and compression-driven fragmentation at rock-crusher contact points.

Aug 24, 2022

By Nabil F. Ismael, Khalid Farraj

"The axial load transfer along large diameter bored piles in very dense silty sand was examined by field tests. Two instrumented piles 1.2 m diameter and with embedded length of 18 m and 25 m were load tested in axial compression to failure in connection with the construction of a big tower building in Kuwait City, Kuwait. Instrumentation included vibrating wire strain gages at various levels, displacement transducers and extensometers. The purpose being to measure the axial load distribution, skin friction, and base resistance at various load levels. In addition the settlement of the piles and the elastic compression were monitored. The ultimate pile capacity, side friction, and base resistance were determined and correlated with the Standard Penetration Resistance values as determined from the boreholes. Most of the load was transferred as side friction and the pile settlements at the maximum loads ranged from 1.6% to 2.2% of the pile diameter.INTRODUCTIONLarge diameter bored piles are used with increasing frequency for heavy structures in Kuwait and the Gulf region in calcareous sand. The behavior of short piles ranging in depth from 8 m to 15 m was examined by field test (Ismael 2012). However, larger diameter and deeper piles are being used more frequently, including the project described in this paper which included piles with 1.2 m diameter and 18 m to 25 m depth. The design of these piles requires knowledge of the skin friction and point resistance in these soils. While field tests on driven piles are available (Ismael 1989, Ismael 1999), field test data on long large diameter piles installed through very dense sands or silty sands are very limited at present. The results of two load tests carried out recently on instrumented bored piles at one site in downtown Kuwait City have become available. In these tests the failure load was extrapolated from the test results. It is important to examine and analyze the test results for the benefit of the geotechnical research and design engineers."

Jan 1, 2017

The need for the hydraulic transportation of coal in the New South Wales coal industry, both from the coal face to the surface and from the coal mine to the consumer or the port for export, is explained. Details of research projects currently in progress and involving the hydraulic transportation of New South Wales coals are given together with information on the hydraulic transportation of coal in the United States of America. The potential of hydraulic transportation as a viable alternative to the proposed expansion and upgrading of the New South Wales railway system to meet the projected New South Wales coal production to the year 2000 is described.

Jan 1, 1980

By R. G. Treuting

Germanium single crystals strained in tension at 600°C slip on the {Ill} plane and, macroscopically at least, in the <110> direction. Deformation is in homogeneous: various localized rotations are observed, as is a banding consistent with secondary slip banding. The structure after deformation is polygonized with a domain size of about 2x1O-3 cm. In relaxation tests, an incubation period prior to flow is observed, of duration inversely related to temperature and applied stress. Under continuous loading, there is a sharp first yield point. A critical resolved shear stress therefore must be cited with respect both to temperature and to rate of loading. At 600°C, when loading proceeds at 2900 psi per min, it is 1310 psi. The yield point phenomenon is suggestive of Cottrell&apos;s solute atom atmosphere theory and five points of qualitative agreement with this theory are found. PLASTICITY of germanium at elevated temperatures has been reported by Gallagher,&apos; who ascribed it to slip on {Ill) planes and described some associated effects. Preliminary experiments with single crystals of silicon and germanium loaded as simple beams confirmed {ill) as the slip plane of both materials.V his was demonstrated by the standard technique employing traces on two surfaces of known angle on a deformed crystal of known orientation.3 These experiments did not fix the slip direction, since more than one glide system operated. Uniaxial tensile straining is preferred for this purpose in order to restrict slip to one predominant system and to provide an unequivocal determination of the orientation change with respect to the stress axis. Experimental Method Specimens were diamond-sawed from germanium crystals containing about 5x10-5 wt pct Sb prepared by the zone-leveling process described by Pfann and Olsen;4 these specimens measured about 81/2 in. long, 0.20 in. wide, and were of various thicknesses from 0.035 to 0.060 in. Prior to testing, a specimen was coated over 1 in. or more of length at each end with Apiezon wax, chemically polished (in a solution of 15 ml HF, 25 ml HNO,, 15 ml CH3COOH, and 3 to 4 drops Br2), and dewaxed in warm xylene. A brief re-etching after scribing through a complete wax coating with vernier dividers provided gage marks at 0.200 in. intervals on the polished surface. A specimen with grips soft soldered to the ends was passed through the furnace tube and the grips pinned to the tensile machine in series with a stress gage. The Schopper testing machine is best described by reference to the illustration on p. 107 of Schmid and Boas5 and is operated with the pendulum arm locked, fixing the upper head. Load is applied through the screw-driven lower head, manually or by reduced speed motor. The furnace is 21/2 in. long surrounding a 4x7/16 in. ID quartz tube and was positioned about the specimen to permit free motion. The inert or reducing atmosphere required was sufficiently provided by a flow of helium introduced at the center of the furnace tube, with the tube ends loosely plugged with asbestos paper. Surface corrosion was slight. The stress gage employs a Be-Cu strip with SR-4 units incorporated in a simple bridge network with provision for balancing and calibrating. The bridge output on loading is fed through a Leeds and North-rup dc amplifier to a Speedomax 10 mv recorder, and calibration is obtained by dead loading. Experiments of two types have been conducted. Most have been in relaxation at constant elongation. One stress-strain curve has been taken with the machine continuously driven. Following extension of a specimen, Laue X-ray photographs were taken to obtain the orientation change between deformed and undeformed regions, recorded on a single film by translating the specimen in a plane normal to the beam between exposures. Sequences of such multiple exposures were made on some specimens to include the entire orientation range on one film. Slip Direction To obtain a maximum orientation change with a single slip system, crystals of very closely <110> axial orientation were used. The classic determination of slip direction rests on establishing that direc-

Jan 1, 1956

By C. S. Boland

The Copper Range Company&apos;s mining properties are located in the Upper Penisula of Michigan. (Fig.). Early work indicated the presence of copper ore in a bedded deposit, confined to the base of the Upper Keweenawan Nonesuch shale, and exploitation of this deposit on a portion of the Company&apos;s property was undertaken by White Pine Copper Company. Diamond drilling of the White Pine orebody indicated that a major fault pattern terminated the values to the South-west. Further drilling Southwest of the fault zone proved a downward displacement of the ore bearing horizon some 1,500 feet and a lateral displacement of approximately 4,000 feet; and in this area an ore deposit was outlined in a large asymmetrical syncline locally plunging to the South-west. (Figs. 2 and 3)

Jan 1, 1962

By Nelson Severinghaus

Consolidated Quarries Corp. must conduct operations for an average sales price of $1.25 per ton, about the same price at which stone was sold 25 years ago when the dollar was worth twice what it is now. To maintain success in a competitive business, the company must solve the usual production problems, which will be discussed here in the order they occur in the flowsheet. Most crushed stone quarries must first remove soil and decomposed rock. Although seasons of lower sales sometimes release regular quarry excavating and haulage equipment for this purpose, overburden is often too extensive for this method to be used. In such cases, special equipment must be assigned or the job may be contracted. As many earthmoving contractors have heavy duty specialized equipment well suited to overburden removal, they should be seriously considered before the job is undertaken. Pockets of clay beneath peaks of hard stone sometimes defy mechanized removal. Pick and shovel laborers at this point might be supplanted by more ingenious use of pumps and water or some other mechanical means. Where overburden is extremely heavy or difficult to remove, underground mining must be considered.

Mar 1, 1956

By Joseph L. Uraco, Harry C. Verakis

The use of explosives in underground coal mines presents a potential risk for serious injuries and death to miners. Widespread disasters have occurred from the explosion of methane and/or coal dust initiated by blasting with explosives. Many of these disasters took place in the early 1900's when the use of black powder for blasting was prevalent. Historically, the investigations in the U.S.A. to develop and test safer explosives for blasting coal began in 1908 when a testing station was established in Pittsburgh, Pennsylvania. Since that time, great strides have been taken in the development of safer explosives. The use of safer explosives has significantly reduced blasting accidents in coal mines. Enactment of legislation, such as the Federal Coal Mine Health and Safety Act of 1969 and enforcement of regulations has also improved blasting safety. More recently, MSHA began a major revision of its regulations for blasting in coal mines. In 1988, MSHA published final rules for the approval and use of permissible explosives in coal mines. The approval requirements for explosives address testing and evaluation. The requirements include tests for sheathed explosives which represent a new technology. The use regulations provide increased safety protection for miners by including standards to address identified hazards. Major aspects of these standards, such as qualifications for blasters, multiple-shot blasting and the use of sheathed explosives are discussed.

Jan 1, 1992

By W. T. Turrall, D. Porter

The paper describes a machine developed for the purpose of concentrating clear optical grade fluorspar crystal from a feed material containing less than 1 pct impurities. The principle of concentration is based on the fact that in a liquid having an index of refraction equal to that of fluorite (n — 1.434) clear crystals are invisible, whereas crystals containing occluded impurities absorb a part of the light. As the crystals pass through a light beam, undesired crystals give themselves away by creating a shadow on a photoelectric receiver. .The shadow is converted by the photoelectric cell into an electric pulse. An electronic circuit amplifies this pulse and commands the operation of a mechanical concentrator. Hp HE crystal laboratory, Dept. of Physics, Massa--*- chusetts lnstitute of Technology, was confronted with the problem of obtaining a supply of optical grade calcium fluoride (CaF,) for use in growing synthetic CaF, crystals. A search of the known fluorspar deposits did not indicate that any quantity of optical spar could be obtained. Even the best material had to be sorted by hand to remove impurities. The process for growing CaF, crystals developed by Professor D. C. Stockbarger of the Dept. of Physics, M.I.T., necessitates very pure feed materials. Exclusion of impurities is required, even in amounts detectable only spectrographically. The impurities occurred as minute inclusions of SiO,, BaSO,, CaCO,, FeS2, water or air. Crystals up to 4 in. in diam and weighing several pounds are made by the Harshaw Chemical Co. in Cleveland. Since the time required to grow a 4-in. crystal is about one week, and since the cost of manufacture is high, removal of impurities by any concentration method appeared practical. The mineral engineering section of the Dept. of Metallurgy undertook to investigate the possibility of concentrating clear optical fluorspar, —4 mesh + 10 mesh, from a feed containing over 99 pct CaF,. Various innovations of the known methods of concentration were considered, but in each case the minute amount of impurities associated with the crystal produced such extremely small differences

Jan 1, 1953

By W. T. Turrall, D. Porter

The paper describes a machine developed for the purpose of concentrating clear optical grade fluorspar crystal from a feed material containing less than 1 pct impurities. The principle of concentration is based on the fact that in a liquid having an index of refraction equal to that of fluorite (n — 1.434) clear crystals are invisible, whereas crystals containing occluded impurities absorb a part of the light. As the crystals pass through a light beam, undesired crystals give themselves away by creating a shadow on a photoelectric receiver. .The shadow is converted by the photoelectric cell into an electric pulse. An electronic circuit amplifies this pulse and commands the operation of a mechanical concentrator. Hp HE crystal laboratory, Dept. of Physics, Massa--*- chusetts lnstitute of Technology, was confronted with the problem of obtaining a supply of optical grade calcium fluoride (CaF,) for use in growing synthetic CaF, crystals. A search of the known fluorspar deposits did not indicate that any quantity of optical spar could be obtained. Even the best material had to be sorted by hand to remove impurities. The process for growing CaF, crystals developed by Professor D. C. Stockbarger of the Dept. of Physics, M.I.T., necessitates very pure feed materials. Exclusion of impurities is required, even in amounts detectable only spectrographically. The impurities occurred as minute inclusions of SiO,, BaSO,, CaCO,, FeS2, water or air. Crystals up to 4 in. in diam and weighing several pounds are made by the Harshaw Chemical Co. in Cleveland. Since the time required to grow a 4-in. crystal is about one week, and since the cost of manufacture is high, removal of impurities by any concentration method appeared practical. The mineral engineering section of the Dept. of Metallurgy undertook to investigate the possibility of concentrating clear optical fluorspar, —4 mesh + 10 mesh, from a feed containing over 99 pct CaF,. Various innovations of the known methods of concentration were considered, but in each case the minute amount of impurities associated with the crystal produced such extremely small differences

Jan 1, 1953

By Raj K. Rajamani, Ilesh M. Shah

Maintaining pH, a routine requirement in many industrial processes, is by no means trivial. The control is troublesome because of the inherent nonlinearity and frequently changing process dynamics. Many researchers in the past have investigated advanced on-line estimation and/or adaptive control techniques to overcome these difficulties. Most methods require the development of a complex mathematical model. The present work deals with the use of a simple and elegant method for pH control, based on the use of fuzzy logic. First, a standard fuzzy-logic controller is discussed, followed by a self-organizing controller. The latter algorithm generates a set of rules based on observation of the process. Thus it is a learning algorithm. The development and application of the algorithms to a laboratory acid-base neutralization experiment are presented. This elegant technique is powerful and deserves attention in mineral pro- cessing.

Jan 1, 1990

By M. Rylatt, E. Legault-Seguin, C. Mohns

"With energy costs increasing and ore grades diminishing, the role of preconcentration in hard-rock mining operations has gained greater interest. Dense medium separation is a process that can be conducted at particle sizes from 250 to 0.50 mm with high separation efficiency, depending on liberation characteristics of the valuable minerals. Pilot-plant case studies conducted at the SGS Lakefield site are presented, including mineral systems such as spodumene, sulfide-bearing gold ores, and complex sulfide ores. These case studies demonstrate that, for amenable ores, mass rejection of 20–60% is possible while maintaining recoveries of greater than 90%.RÉSUMÉ Au vu de la hausse des coûts liés à l’énergie et du déclin de la teneur des minerais, le rôle de la préconcentration dans les exploitations minières en roche dure présente un intérêt croissant. La séparation (ou concentration) en milieu dense est un processus pouvant être mené sur des calibres de grains de 250 à 0.50 mm avec un rendement élevé de séparation, en fonction des caractéristiques de libération des constituants des minéraux métallifères. Sont présentées dans cet article des études de cas menées dans des usines pilotes du site de Lakefield de SGS, lesquelles incluent des systèmes de minéraux tels que le spodumène, les minerais aurifères sulfurés et les minerais sulfurés complexes. Ces études de cas montrent que pour les minerais présentant les caractéristiques de libération appropriées, il est possible d’atteindre un rejet en masse de 20 à 60 %, tout en maintenant des récupérations supérieures à 90 %.INTRODUCTIONPreconcentration is the process of rejecting gangue minerals while ensuring recovery of valuable minerals prior to more intensive, downstream processing. Preconcentration has been practiced in the industry for many years, and is gaining greater interest as the industry copes with processing lower grade, more difficult ores, which typically require finer grind sizes and incur higher energy costs.The benefits of preconcentration are:• lower mining costs, which allows for nonselective mining;• lower process capital and operating costs (e.g., resulting from reduced grinding, flotation, and fines disposal stages);• increased ore reserves, which provides the potential to treat lower grade ore;• increased mine production without expansion of the existing plant or concentrator;• reduced overall tailings impoundment by converting the reject into a byproduct (e.g., underground backfill or aggregate);• improved efficiency of downstream processes (e.g., silica removal in electric arc furnace feed, removal of softer sliming minerals prior to grinding);• potential application to brownfield operations and greenfield projects; and• a “green” process option, which reduces processing energy consumption;– reduces mill feed;– increases stage metal recovery (higher grade feed);– increases mill metal output per tonne processed;– reduces surface plant, tailings dump, and tailings pond requirements because the plant has a small footprint and can be installed underground; and– can be applied to retreatment of old tailings dumps to recover metal values and reduce environmental impacts (e.g., dissolved metal runoff, acid drainage)."

Jan 1, 2017

By Robert C. Horton

The Getchell Mine is located on the east flank of the Osgood Mountain Range in the Potosi Mining District, Humboldt County, NV. Mining in the area first began in 1883 for copper, lead and silver in skarn-related deposits. Tungsten was discovered in the skarns in 1916 and was mined sporadically until 1957. The first major discovery was made in 1933 when two Winnemucca prospectors, Edward Knight and Emmett Chase, found gold at the present site of the Getchell gold mine. In 1934, after a small amount of preliminary prospecting, the claims were purchased by Noble H. Getchell of Midas, NV. The Getchell Mine Inc. was organized and exploration and development work began on a broad scale. Major funding was provided by George Wingfield and investors he assembled. Laxalt described Wingfield’s immediate history prior to his financing of Getchell as follows.

Jan 1, 1999

By H. J. Struth

Gasoline is undoubtedly of major importance not only to the petroleum refiner but to the producer. To study the economic aspects of gasoline is, in a measure, a constructive effort to solve the problem of overproduction not only for the refiner but for the entire petroleum industry. After all, the prime object of producing crude petroleum is to supply motor fuel and lubricants to nearly 25,000,000 American motor vehicles, not to mention the increasing demand for these products abroad. Since gasoline furnishes the chief source of revenue to the refiner, it follows that this important product should veritably become recognized by all branches of the petroleum industry as an almost infallible index of day to day requirements of the producer and the refiner. A careful study of gasoline statistics over the past decade or more reveals that there is a definite correlation between world-wide gasoline requirements and the demand for crude petroleum, as well as all other petroleum products. This leads the writer to the conclusion that gasoline is literally the economic yardstick of the entire petroleum industry. Control of Operations That the refiner has begun to recognize the urgent need for controlling his operations is evidenced by the results of the past three years. Unfortunately, it is a difficult problem to convince the refiner that he cannot run crude in excess of the demand for gasoline, without incurring a consequent decline in the market value of this and all other products of distillation. Undoubtedly, he still has much to learn in this respect. Few commercial products have enjoyed such phenomenal growth in demand as has gasoline, and, at the same time, few products have failed, as has gasoline, to reap financial benefit from the popular demand for a national necessity. Perhaps this unprecedented demand was responsible for the overextension of retining facilities, which resulted in the excesses of recent times; at any rate, as the demand for gasoline grew by leaps and bounds, so the refining industry continued to increase its capacity for

Jan 1, 1929

By D. Erik Spiller

Mineral processing technologies are being used in the environmental arena for remediation and secondary recovery. Comminution and/or scrubbing for liberation, coupled with separation of the liberated particles, is known as soil washing. Other metallurgical unit operations have found application in remediation and recycling: size classification, gravity concentration, flotation, magnetic and electrostatic separation, eddy current separation, and liquid/solid separation. This paper presents specific examples of the use of these technologies to clean up contaminated soils and plant residues, and to recycle valuable materials from waste streams.

Jan 1, 1993