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By Frank C. Morris

This report presents the results of a Bureau of Mines study to identify clays found in several petroleum-reservoir rocks in the Tejon-Grapevine area, Kern County, Calif., and to determine the effect of water sensitivity of the clays on the permeability of the reservoir rocks. The clays in the porous rocks were examined in detail, and the clay-mineral types were identified by differential thermal analysis, X-ray diffraction, and optical and dye-staining methods. Fresh-water damage to the permeability of the oil-reservoir rocks was indicated by a study of 125 core samples from productive formations. The study indicated that, although clays were generally less than 5 percent of the reservoir rocks, they swelled in water, particularly fresh water, and nearly blocked the flow channels through which oil flows to the well, effectively reducing the permeability of the formations. The average permeability of rock decreased from 1,600 millidarcys in air to 620 millidarcys in salt water and 120 millidarcys in fresh water. The dominant clays in the oil-bearing sandstones were members of the montmorillonite group. They were associated with smaller quantities of clays found to be in the mica or illite group. None of the cores appeared to contain clays of the kaolinite group. In the lower section of the J.V. sandstone indications of what appeared to be the mineral sepiolite were noted.

Jan 1, 1959

The Bureau of Mines recognized the need for a demonstration program to distribute and apply existing information regarding the illumination of working places in mines. This report details the performance of illumination systems which were installed on several different types of mining machinery.

Jan 1, 1978

By Kenneth M. Maas

The Bureau of Mines inventoried the land in southwestern Alaska to classify ownership and availability and compared this land with known mineral terranes and mineral deposits. This report discusses and quantifies the potential for favorable location of mining claims for metalliferous (locatable) mineral deposits. Of the nearly 24 million acres that constitute the study area, approximately 3.6 million acres or 17% are available for mineral location, 3.4 million acres or 14% are available with restrictions, and 17 million acres or 71% are unavailable. Mineral terranes are known to underlie about 7.8 million acres or 33% of the study area; 3 million acres or 38% occur on land available for mineral location, 1.3 million acres or 17% occur on land available with restrictions, and 3.5 million acres or 45% occur on unavailable land. The State of Alaska has opened over 91 % of its land in the study area to mineral location; in comparison, the Federal Government allows mineral location on 0.07% of the land under its jurisdiction. There are 117 known mineral deposits or occurrences within the study area, including 77 lode deposits and 40 placer deposits. Of the 41 lode deposits occurring within a mineral terrane, 2 occur on available land.

Jan 1, 1988

By Madan M. Singh

This report presents the results of an investigation of inclined roof bolts, anchored over pillars, in room-and-pillar coal mines susceptible to shear failures of the roof. Although the field data do not support this contention, it is believed on the basis of analyses and other work that inclined roof bolts do offer potential under some circumstances.

Jan 1, 1978

By Nelson P. Hulst

COMMITTEES. DULUTH.-Nelson P. Hulst, Chairman; J. B. Adams, W. C. Agnew, M. H. Alworth, C. W. Andrews, R. Angst, William R. Appleby, C. E. Bailey, G. G. Barnum, E. F. Bradt, Mylie Bunnell, George L. Cheesebrough, Peter Christen¬sen, F. A. Cokefair, T. F. Cole, C. A. Congdon, N. Cowling, George H. Crosby, M. D. Cullum, C. d'Autremont, Jr., H. L. Dresser, C. T. Fairbairn. Walter Fitch, F. L. Gilbert, J. T. Hale, G. G. Hartley, E. B. Hawkins, M. S. Hawkins, J. H. Hearding, Louis Hill, L. J. Hopkins, F. E. House, J. C. Hunter, 0. D. Kinney, J. W. Kreitter, E. J. Longyear, Alexander McDougal, W. A. McGonagle, A. M. Marshall, W. N. Merriam, T. D. Merrill, John Millan, P. Mitchell, Clarence Moore, Hon. Page Morris, C. H. Munger, Henry Nolte, W. J. Olcott, A. L. Ordean, Thomas Owens, F. A. Patrick, H. M. Peyton; D. M. Philbin, Capt. Charles Potter (U. S. A.), L. W. Powell, Harry Roberts, Louis Rouchleau, George A. St. Clair, J. U. Sebenius, Joseph Sellwood, Amos Shepherd, W. B. Silvey, George Spencer, George C. Stone, H. B. Sturtevant, George D. Swift, Kirby Thomas, C. D. Thompson, A. D. Thomson, G. A. Tomlinson, Charles Trezona, R. R. Trezona, Maj. J. H. Upham, Charles Van Barneveld, W. W. Walker, J. L. Washburn, A. C. Weirs, H. J. Wessinger, A. B. Wolvin, Dwight E. Woodbridge. HOUGHTON.-W. E. Parnall, Chairman; W. D. Calverley, Secretary; W. B. Anderson, L. S. Austin, Jacob Baer, William Bath, F. J. Bawden., Simon Beahan, John Been, C. H. Benedict, Walter Bloomfield, S. H. Brady, Samuel Brady, Henry Brett, A. L. Burgan, F. I. Cairns, W. H. Cake, Arthur L. Carnahan, William Carpenter, Phillip Carroll, John J. Case, T. L. Chadbourne, W. A. Childs, B. F. Chynoweth, Captain James Chynoweth, H. P. Clausen, F. G. Coggin, H. D. Conant, J. B. Cooper, J. R. Cooper, John Cuddihy, Thomas Cummings, Robert Davidson, J. B. Dee, J. R. Dee, T. S. Dee, Theodore Dengler, M. M. Dennis, Captain Thomas Dennis,. F. W. Denton, A. D. Edwards, R. M. Edwards, C. S. Fales, Daniel Fisher, Henry Fisher, James Fisher, A. L. Floeter, Frank H. Getchell, M. C. Getchell, W. M. Gibson, W. M. Gilliland, James G. Glanville, George Goodale, H. S. Goodell, A. R. Gray, Edward Grierson, Homer Guck, H. D. Haddock, Captain Josiah Hall, John L. Harris, Captain S. B. Har¬ris, Enos Harrold, F. William Hartmann, George L. Heath, C. M. Hoar, Thomas Hoatson, 0. P. Hood, Captain Thomas Hooper, Captain Joshua D. Husking, Dr. L. L. Hubbard, Arno Jaelinig, E. D. Johnson, G. A. Koenig, Edward Koepel, C. H. Krause, R. H. Leach, A. W. Leonard, James MacNaughton, Edward McCormick, Thomas McDonald, R. T. McKeever, F. W. McNair, James McRae, John Mackey, John C. Mann, Major G. A. Marr, Captain Thomas Maslin, Harry Mercer, James Merton, Michael Messner, William F. Miller, Captain J. Milligan, Dr. J. W. Moore, Charles H. Moss, H. F. Nickerson, Charles L. Noetzel, P. H. Paine, John Penrose, Captain John Pentecost, Graham Pope, R. C. Pryor, James Ramsay, J. T. Reeder, Allen F. Rees, J. H. Rice, W. G. Rice, James

Jan 1, 1905

By Paul M. Tyler

Magnesite is of importance primarily as a refractory material for lining steel furnaces , although substantial amounts are used in the production of flooring compositions and other building materials and for certain chemicals , notably epsom salts . Since consumption for all of these purposes is largely in the eastern United States and domestic deposits are situated in California and Washington , this country's magnesite mining industry , which was created largely by war- time conditions , has subsequently been sustained by tariff protection .

May 1, 1931

By William W. Odell

Certain gas-making processes are in use in Europe, particularly in Germany, which differ radically from those in common use in America. A number of them are of particular interest because they are different. The questions naturally arise: Are any of them applicable to the making of gas in this country and, if so, with what particular type of solid fuel? It is a fact that some of them were developed with consideration of a particular set of conditions and for the utilization of solid fuels available in Germany. The latter fuels, in certain characteristics, are unlike the high-rank fuels commonly used for making gas in the United States; therefore, in attempting to evaluate the various foreign- developed processes with regard to usefulness here, one must give attention to the particular conditions that will prevail in any specified case and also the characteristics and requirements of the process and generator under considera- tion. Three of the processes that were developed and put into commercial operation in Germany, and which have some characteristics in common, are con- sidered in particular in this publication; they are: 1. Lurgi pressure gasification process. 2. Winkler process. 3. The Leuna slagging-type producer-gas process. Each of these processes requires steam and oxygen as gas-maiding fluids. For a number of years, oxygen, has been used in a relatively pure state,. along with steam, in making gas in Germany, and many of the difficulties initi-. ally encountered have been overcome. Although it appears that oxygen recovered from air was first used in this manner as a method of utilizing a byproduct in a plant that used the nitrogen complement in the manufacture of ammonia; more recently, the oxygen was made particularly for the purpose. The fuels - brown coal or lignite used in processes 1 and 2 were not suitable for use in the older and commonly used intermittent-type water-gas generators, and it was necessary, therefore, to devise a different process for gasifying them. A gas of higher heating value than producer gas, was desired, and the use of oxygen (not air) along with steam made possible the production of the desired gas without nitrogen dilution, which characterizes producer gas. Operating data presented herein are based upon observations by, members of the Technical Oil Mission at plants in Germany, on records, and on information vocally given to members of the lässion, including the author, while visiting those plants, and they are believed to be reasonably correct; however, certain hasic observations, comparisons, and conclusions are. made by the author.

Nov 1, 1947

By James R. Aggson

This paper summarizes the research effort that was conducted as part of a cooperative agreement between the U.S. Bureau of Mines, Denver Mining Research Center and the Pittston Company. The objective of this investigation was to further the understanding of the floor heave ground control problems that have plagued underground mining of the Beckley coalbed in southern West Virginia. Floor heave is both economically and structurally undesirable. Floor heave is accompanied by a redistribution of stresses and loads that are associated with an underground opening. This redistribution of stresses may cause roof or pillar problems that otherwise would not have occurred. The floor heave that occurs in the Beckley coalbed is not cons1dered to be caused by "squeezing" or plastic flow of the materials involved. The "squeezing" type floor heave is normally associated with relatively weak floor members that contain significant amounts of clay mineralization. The floor members in the Beckley coalbed are competent, relatively strong materials which fail in a manner that can best be described by the term "buckling." This buckling-type failure is indirectly related to the time-dependent deformation properties of the materials involved, but is considered to be more of a slender column, or panel, type failure than a "squeeze" or "flow"-related failure. The Beckley coalbed has had a history of floor heave ground control problems. The Glen Rogers mine, which opened in the 1920's, experienced extensive floor heave. In a report dated April 1929, James P. Keatley of the West Virginia State Department of Mines described the floor heave in the Glen Rogers mine. Several observations listed in the Glen Rogers report that appear to be consistent with current observations follow: 1. Water plays no apparent part in the floor heave process. 2. No evidence of gas has been found in the floor. 3. The thickness of the overburden, which varies from 183 to 396 m (600 to 1300 ft), has no relationship to the floor heave. In the conclusions of the 1929 report on the Glen Rogers mine, Keatley states, "A statement in brief as to the cause (of floor heave) would lie that an undetermined natural condition doubtless augmented by former and present mining methods causes the bottom to heave." As this report will show, Mr. Keatley's insight into the problem was most accurate. The "undetermined natural condition" is the existence of a biaxial, horizontal, compressive stress field. This stress field is in excess of that which would be expected from gravity loading. This stress field and the material properties of the floor rock combine to cause the floor heave that has been experienced. The floor heave that occurs in the Beckley seam generally occurs as arching, with a tension fracture, near the center of the floor span or as a break near the rib followed by vertical deflection (of the floor) at the rib and sloping of the floor across the entry. Examples of the floor heave are shown in Figures 1 and 2. The two types of floor heave are merely different manifestations of the same basic failure mechanism. When the entries experiencing floor heave were identified on a map of the mine under investigation, it was apparent that there was a relationship between the floor heave and the direction of the entries. The main entries, which are used for ventilation and haulage, experienced the majority of the floor heave. This directional relationship suggested a directionally related loading mechanism, or more specifically, a biaxial, horizontal stress field that exceeds what would be expected by gravity loading. Since the main entries were oriented at a bearing of N25oW, it was hypothesized that the maximum compressive component of the horizontal stress field was at 90° to these entries or at a bearing of N65oE. An in Situ testing program was developed to test this hypothesis and investigate the floor heave problem.

Jan 1, 1978

By L. B. Sand

Zeolite ores and protores occur in extensive deposits in the western United States. A recent paper1 describes the general geology and mineralogy of these deposits and their geographical distribution. The zeolites are alkali-and silica-rich varieties of mordenite, erionite, chabazite, phillipsite, ferrierite, and clinoptilolite. The zeolites were formed primarily by the alteration of Tertiary pyroclastics and in some cases by the alteration of Tertiary siliceous flows. The altered pyroclastics are of principal economic significance. The volcanic ash and tuff were deposited in restricted basins where saline lakes developed. The pyroclastic layers often are of uniform thickness and macrotexture for miles from the center of the basin and interfinger with detritals toward the edge of the basin. Thus, in addition to unaltered volcanic glass, the gangue minerals in these deposits include some combination of primary minerals in the pyroclastics, alteration products of the glass other than the zeolite of interest, and detrital minerals. The gangue minerals include quartz, cristobalite, tridymite, opal, orthoclase, micro cline, montmorillonite, hornblende, calcite, gypsum, thenardite, and iron oxides. The presence of one or two other zeolites in the layer in some cases also is considered as gangue. There are no quantitative mineralogical descriptions of these deposits in the literature; this: study was undertaken to obtain this information. As the zeolites occur as single crystals, crystal aggregates, zeolite-glass particles and in cemented aggregates, a method of study was chosen which would give the size distribution of the zeolite in these types of association. For this reason dispersion of the rock was achieved with a minimum of grinding action. This excluded those zeolite ores, silicified by hydrothermal altera¬tion which require grinding. A relative index of the ease of disaggregation of the zeolite ores thus is obtained, but the technique does not give absolute size distributions of the zeolite crystals. Samples were selected for analysis which do not necessarily represent the best ore horizon, but do represent a spectrum of zeolite occurrences from significant deposits. They are mordenite, erionite, and phillipsite from Rome, Oregon, clinoptilolite and chabazite from Reese River, Nevada, chabazite (and var. herschelite) from Bowie, Arizona, erionite from Jersey Valley, Nevada, and erionite from Pine Valley, Navada.

Jan 1, 1967

By Gordon T. Austin

The combined value of production of natural abrasives, which include tripoli, special silica stone, garnet, staurolite, and emery, increased in 1993. The increase in the value of tripoli production was the result of an increase in total production. Special silica stone experienced an increase in unit value but decrease in the quantity produced. Garnet showed a 19 % decrease in quantity and an 8 % decrease in value. Staurolite increased about 51 % in the quantity produced and 136 % in value compared with those of 1992. Staurolite's significant increase in value of production resulted from a 56 % increase in the unit value. The fused aluminum oxide industry showed an 8 % decrease in the quantity produced and a 13 % decrease in the value of production. The silicon carbide industry saw an 11 % decrease in the quantity produced and an 8 % decrease in the value of production. Combined, the industries decreased 9 % in quantity and 11 % in value compared with those of 1992.

Jan 1, 1993

By W. V. Swarzenski

In its, effort to combat waterlogging and coil salinity, the later and Soils Investigation Division of WAPDA (West Pakistan's Water and Power Development Authority) has carried out an extensive program of test drilling and water sampling, since 1954. Data collected during the past ten years have permitted the delineation of fresh and saline ground-water-zones in the Punjab Plain. Fresh ground water containing generally, less than 500 ppm (parts per million) of total dissolved solids is found in wide belts paralleling the major rivers and in other areas of fresh-water recharge. Locally, fresh ground water extends to depths of 1,500 feet and more. Saline ground water occurs downgradient from sources of recharge, particularly in the lower central parts of the interfluvial areas and, presumably, underlies most of the Punjab Plain. The ground waters of the Punjab are characterized by their evolution from calcium, magnesium bicarbonate waters, near sources of recharge, to waters containing a dominant proportion of sodium. The highly mineralized waters of the Punjab are generally of the sodium chloride type, whereas in Dera Ismail Khan District sodium sulfate waters predominate. The pattern of distribution of saline ground-water zones and the observed gradual increase in mineral content, downgradient from sources of recharge, can be explained best by a hypothesis stressing the processes of evaporation from the water table and solution of minerals within the alluvial aquifer.

Jan 1, 1967

By M. Onifade, O. S. Otuogbai, A. F. Mulaba-Bafubiandi, O. D. Eniowo, H. Grobler

Artisanal and small-scale miners in Nigeria struggle to attract formal financing to upgrade their operations to a more sustainable form of small-scale mining operation. Literature shows that for an investment to attract formal sources of financing; the business must be considered creditworthy by potential lenders. This means that the credit risks associated with the investment must be bearable for the potential lender. This study looks at how artisanal and small-scale miners can attract formal funding, which will help them take the leap from artisanal state to a form of sustainable small-scale mining operation. This study evaluates the creditworthiness of artisanal and small-scale mining operators using key credit risk parameters identified in the literature and through primary investigation. A quantitative study is conducted on a sample of 100 artisanal and small-scale miner establishments in Nigeria to evaluate the effect of these identified credit risk parameters on creditworthiness. It is shown in this study that being a member of a mining cooperative society, which is a form of social collateral, best improves the chances of access to formal financing for miners within the sample group. This underpins the role of social collateral, in both the formal and informal economy, and its influence in improving the creditworthiness of a typical artisanal and small-scale miner.

Jul 23, 2025

By Robert F. Mehl

Jan 1, 1944

By Eddie C. Chou

Phelps Dodge, Inc. (PD) is currently developing a lateritic nicke/Vcobalt deposit in Madagascar. Hazen Research, Inc. provides technical assistance to PD to investigate recovery processes for nickel and cobalt. Various process options were evaluated in laboratory experiments and pilot plant operations. The process selected for the feasibility study consists of feed preparation, high-pressure acid leach, countercurrent decantation wash, sulfide precipitation, sulfide dissolution, solvent extraction, ion exchange, and electrowinning. Among these unit processes, high-pressure acid leach, sulfide precipitation, and sulfide dissolution are applications of pressure technologies. Process development work and design criteria for commercial operations of these unit processes are presented in this paper. Concerns related to scaling in the high-pressure acid leach and the sulfide precipitation processes are discussed. Corrosion of various metal coupons under these environments was examined.

Jan 1, 2000

By W. K. Smith, V. P. Krueger, D. C. Mulder

"AbstractThis paper describes the geological procedures used to evaluate two mineable high-volatile C bituminous coal seams at Coal Valley , located in the outer foothills belt of the Rocky Mountain Eastern Slopes in west-central Alberta. Lexco Testing Ltd., the exploration arm of Luscos: Ltd., owns and operates an all -weather geophysical logging system which provides gamma, focused density , single-point resistance and caliper logs in a single pass. A mathematical analysis for a theoretical interpretation of the single-point resistance log confirms empirical research that bed boundaries are located at a point 10% from the bottom of the curve. A unique and efficient triple-tube, wireline rotary coring system cuts an undisturbed 0.076m- diameter core in a plastic liner at recoveries exceeding 90% . Although only 10% of the total footage is cored, it provides vital analytical and geotechnical data, and, when integrated with the geophysical logs, improves the quality and extends the usefulness of interpreting both sets of data. All data are programmed to produce computerized structure contour, isopach, isoratio and isoquality maps, and volume calculations.General IntroductionTHE COAL VALLEY AREA is located in the outer foothills belt of the Rocky Mountain Eastern Slopes, 60 miles (96 km) by road southwest of Edson, Alberta. Luscar Ltd. holds leases which total 49,000 acres (19,830 ha) , of which 18,300 acres (7,410 ha) have been assigned to the Coal Valley mine area (Fig. 1 ) . There are two Paleocene high-volatile C bituminous coal seams initially developed for mining within a total stratigraphic interval of 750 feet (230 m ) (Fig. 2 ). These seams strike generally NW, and in the undisturbed areas generally dip westerly from 10 to 30 degrees."

Jan 1, 1977

By H. S. Caldwell

A magnesium-base incendiary alloy, containing about 20 percent cadmium, 4 percent aluminum, and 0.5 percent zinc, was investigated in a series of vacuum-distillation experiments to determine the feasibility of recovering magnesium and cadmium as refined metals. Alloys prepared in the laboratory and actual bomb-casing alloy were studied at temperatures of 550° to 750° C. and pressures of 100 to 150 microns. Simple distillation and fractional distillation methods were only partly effective in separating the cadmium and magnesium. They were separated satisfactorily, however, with a special vapor baffle designed to condense the metals selectively. Magnesium and cadmium products were 99 percent pure and together comprised 82 percent of the total condensate. About 17 percent of the condensate was intermediate-grade alloy that could be recycled with new charge and contained about 70 percent magnesium and 30 percent cadmium.

Jan 1, 1959

By S J. Clarke, C S. Walker

The South West Rail Link (SWRL) project involved construction of a rail line to service new residential areas in south-west Sydney. The 11 km rail line is conveyed through a short tunnel at shallow depth where it crosses beneath the eight lanes of the Hume Highway. The underpass location is one of the most heavily trafficked within Sydney’s motorway network.The New South Wales Roads and Maritime Services (Roads and Maritime), as the owner of the highway asset, had the responsibility of managing the risks to the highway and traffic associated with the tunnelling project from the pretender stage through to completion. This paper considers the primary risks and mitigation measures employed, including geotechnical investigation, and development of appropriate construction constraints and concept design of an extensive real-time survey system to monitor pavement deformation during the tunnel works.The geology comprises fresh Minchinbury Sandstone in the tunnel invert and side walls, and variably weathered Bringelly Shale in the haunch and crown. Few tunnels have been excavated in these rock types in Sydney, and there is little information relating to the in situ stresses and stress-relief deformations in these materials.During tunnel construction the monitoring data indicated unexpected surface heave of up to about 24 mm. A multiparametric back-analysis of the deformation data is presented, which provides information on the deformation mechanisms and key geotechnical parameters, including rock mass modulus and in situ stresses.The approaches and methodologies developed for the SWRL underpass were effective in maintaining the safe operation and traffic capacity of the highway throughout the construction period, and the analysis of the monitoring data provides a useful reference for similar future projects, or projects constructed in similar ground conditions.CITATION:Clarke, S J and Walker, C S, 2014. Deformation mechanisms of the South West Rail Link underpass beneath the Hume Highway, in Proceedings 15th Australasian Tunnelling Conference 2014, pp 631–640 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 17, 2014

By Leon Y. Sadler

Equations which predict the unsteady-state response of the continuous froth flotation cell to changes in operating conditions are necessary for the rational design of an automatic flotation cell control system. Unfortunately application of automatic control to froth flotation separation equipment has lagged behind application to other types of separation equipment (for example distillation columns, absorbers, liquid-liquid extractors, etc). This may be due partly to the unavailability of suitable mathematical models for predicting the dynamics of continuous mechanical froth flotation cell. This paper presents the results of a comparison of four dynamic flotation models (in transfer function form) using the same set of unsteady-state continuous flotation data. One of the transfer functions tested has been presented previously in the literature (1), another (2) has been accepted for publication, and two are given here for the first time. In addition, data are presented which confirm earlier findings that the mixing in the rotor-stator type cell is nearly perfect. The specific purposes of this paper are to: (1) provide the automatic control systems designer with several alternative dynamic mathematical models of the continuous mechanical froth flotation cell (2) give some idea of the relative a¬bility of each model to predict unsteady-state behavior by fitting each model to the same set of experimental stimulus-response flotation data and (3) provide more insight into the macro-mechanisms prevailing in the continuous mechanical flotation cell. The dynamic models which are presented and tested here all relate the time variation of the concentration of a given floatable mineral in the tailings to a time-dependent disturbance in the same floatable mineral concentration in the feed to the flotation cell.

Jan 1, 1972

By A. Saigal

The effect of temperature on the cutting forces during machining of alumina reinforced aluminum composites was investigated, Aluminum 6061, 10% Al2O3 reinforced composite and 20% Al2O3 reinforced composite were tested, A 5/8-inch diameter high-speed steel end mill, a Micro 100 TiN coated single edge endmill cutter and a two-fluted solid carbide insert cutter were used for tooling, The results, in general, showed an increase in the cutting forces as the temperature of the material increased, From the raw data, there are temperatures ranges in which the force data did decrease but they were insignificant with regards to predicting a downward trend. A regression analysis was used to understand which variables had the greatest affect on the forces being generated, The correlation and regression analysis showed that at 600 rpm (velocity: HSS- 98,2 sfpm, Micro 100 cutter - 78,5 sfpm, solid carbide cutter - 192,4 sfpm) the tooling, the workpiece material, built up edge, and temperature were statistically significant factors in the test, Tooling was a significant variable in all testing, The smallest forces recorded during machining were generated with the solid carbide two-fluted endmill cutter, Visually, the solid carbide tooling produced a better surface finish during the testing which made it the tool of choice, In addition, the force data proved that as the cutting speeds were increased, the cutting forces decreased.

Jan 1, 2005

By S. W. Ip

Over the years, the importance of surface and interfacial phenomena has been neglected by the copper-nickel industry. As a result, little data on the surface and interfacial tension of the Ni matte and slag system are available in the literature. In view of the scarcity of information in this area, the surface tensions of the Ni-Fe-S system together with the Ni-Fe-S and fayalite type slag system were measured using the sessile drop technique. Drop images were obtained by X-ray radiography. For the Ni-Fe-S system, the results showed that the surface tension of the matte increases with matte grade. The surface tension behavior with changing matte grade showed a slight negative deviation from ideality. This indicated that FeS is slightly surface active in the nickel matte system. Results also indicated that small increase in sulphur content in the matte can decrease the surface tension quite significantly. The measured surface tension of the Ni-Cu-S system showed a linear relationship with the Cu2S content in the matte. The surface tension decreased with Cu2S content. Interfacial tension measurements showed a similar trend. That is, interfacial tension increased with increasing matte grade. The presence of MgO (-1.5%) and A12O3 (-6%) in the slag does not affect the interfacial tension value. Effects of matte surface tension on phenomena such as entrainment of matte in slag and infiltration of matte into refractory pores are discussed. The calculated flotation coefficients indicated that flotation of nickel mattes cannot be avoided by changing the matte grade. Filming of matte on bubbles can occur below a matte grade of about 19% Ni3S2. As for infiltration, refractory bricks containing high Cr2O3 will be easily wetted by matte regardless of matte grade. Therefore, bricks containing high Cr2O3 can easily be infiltrated by liquid matte.

Jan 1, 1993