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In 1987 the control strategies at the then ZC Mines' New Broken Hill Consolidated concentrator were a miscellaneous mixture of computer hardware and technology for ISA, grinding and residue thickener control. Field instrumentation was based on current-to-air technology of approximately the 1960s. Decisions were made to rationalise computer and field instrumentation technologies; the object being to consolidate control loops into one system to enable expansion of the system to include all facets of plant operation. The first stage was to install a DEC Micro PDP 11/23 computer and serial line communication as recommended by AMDEL Ltd, for the ISA system, as discussed by Walsh and Freeman (1988). The second stage was to select and install a distributed control system for the centralisation of the control loops into one system, and to replace field instrumentation with state-of-the-art technology. This paper deals with the second stage of the rationalisation, in an attempt to give an insight into what is required when personnel are faced with such a decision, details of costs involved in keeping a system functioning and utilised; and the requirement to train personnel for acceptance of further control strategies.

Jan 1, 1991

Francis Drake, Bulawayo, Rhodesia, So. Africa (communication to the Secretary *):—I should like to place on record some data in addition to those given by Mr. Canby in his paper. I regret that my notes have been destroyed so that I can give no accurate measurements of the water jacket that I am about to describe. This furnace mas erected in Cerro Gordo, Inyo county, Cal., early in 1875, and I think it quite possible that it was the first applied in lead smelting. It was made of plate iron and elliptic in shape, the inner dimensions being about 54 by 42 in. by 48 in. high. The distance between the inner and outer plates was about 6 in. Tuyere holes, one at the back and two on each side, about 12 in. in diameter, were made in this, and in these were placed cast-iron water tuyeres about 16 in. long, the diameter of the blast orifice at the point being about 3 in. The height from tuyeres to feed door was about 9 ft., but the top of the charge was kept about 5 ft. above the tuyeres. There was a space of about 12 in. between the jacket and the top brick-work. This brick-work was supported by a cast-iron plate resting on four cast-iron columns. At the beginning, the jacket was lined with air-dried radial bricks, made of crushed quartz and fire-clay, as it was thought that the jacket would not stand the heat on its bare plates. After a short time the practice was altered and no lining mas put in. The jacket was closed at the top and had a steam drum connected by two pipes at the back. This steam drum was connected to the boiler in which the steam was made for driving the Baker blower, the rock breaker and the pumps. The bottom of the jacket mas also connected to the boiler. The jacket was run under boiler pressure (80 Ib.) for some time, but eventually cracks developed in the inner plate between the tuyere holes,

Jan 1, 1913

By E. E. White

I DISAGREE with Mr. Brinsmade on several points, and I will discuss his remarks under the same six topics which he has used. 1. Rate of Interest Earned by Sinking-Fund.-I believe Mr. Brinsmade is confused in his ideas as to the effect of new gold on the interest earned on money. The flood of gold which he mentions certainly should not operate, to increase interest rates, but since it replaces and adds to liquid capital should reduce interest rates and counteract the destruction of liquid capital which he mentions. Furthermore, it is doubtful if the destruction of capital since 1897 by wars and catastrophes has been any greater in proportion than in similar periods before 1897. With regard to savings banks, I would say that only 3 per cent. is allowed on deposits through a large part of the West. As to bonds, they can be bought to yield any rate. of interest desired up to 6 per cent., but, a 5 per. cent. bond is not as safe as a 4 per cent. bond, nor a 4 per cent. bond as safe as a 3 per cent. government security. I do not understand why Mr. Brinsmade says that Mr. Denny's quoted opinion of a 3 per cent. rate is evidently based on English conditions before the Boer War. Certainly there is no reference to the Boer war or to English conditions in Mr. Denny's article. M. Howard Burnham, in his admirable work on mine valuation, says': ". For instance, redemption is taken at 3 per cent., because even 4 per cent. represents a greater risk, as is indicated by the purchase of Government paper to bear only 3 per cent., the great desideratum of the .latter being security." . Again, Mr. Burnham says:2 "The tables are calculated on the assumption that the dividends shall accumulate at 3 per cent. only, as in accordance with the general idea set out elsewhere, a rate greater than 3 per cent. involves appreciable risk with which it were inaccurate to saddle the sinking-fund if risks are to be segregated, this being the basis of all the writer's calculations."

Jan 6, 1914

By John P. Hager, Adolfo R. Zambrano

The thermodynamics properties of the liquid Pb-Ag-Au system have been determined from galvanic cell measurments five pseudobinary systems of fixed XAg/XAu ratio. The galvanic cell employed a molten PbO-SiO2 electrolyte and was operated between 775" and 1030°C. The thermodynamics properties of lead were obtained directly from the experimental data, whereas the excess integral molar properties and the activities of silver and gold were obtained by means of the Gibbs-Duhem equation. The calculated proper -ties of the Ag-Au system agree well with the published properties. The liquidus surface of the Pb-Ag-Au system has been determined at 1200°K. In Parts I' and 11' the galvanic cell Mo,Pb(l)|(PbO-SiO2)(l) SiO2(s) |Pb(alloy)(l), Mo [I] was used to determine the thermodynamics properties of the Pb-Ag and Pb-Au systems, respectively. The use of cell I, in which a molten oxide electrolyte is employed rather than the classical fused-salt electrolyte, was shown to result in more accurate ther-modynamic measurements in that the displacement reaction at the alloy-electrolyte interface (l/Zb)B(alloy) + (I/za)A+Za = (1/Za)A(alloy) + (1/Zb)B+zb [1] was minimized. For the Pb-Ag system, where B = Ag(l), the error in the activity of lead (aPd) re-sulting from Reaction [I] was calculated to be less than 1 pct.l For the Pb-Au system the error in aPb was calculated to be less than 0.5 pct.2 Also, electro-transport measurements on the PbO-SiO2 electro-lyte1,2 established that the conduction was entirely ionic and that lead was present only in the divalent state. In the present study the experimental technique is extended to an investigation of the thermodynamic properties of the liquid Pb-Ag-Au system. Five pseudobinary systems of fixed X Ag/XAu ratio were selected. The experimental results were then combined with the previous measurements on the component binary systems Pb-Ag1 and Pb-AU2 to calculate, by means of the Gibbs-Duhem equation, the molar and partial molar mixing properties for the liquid ternary solutions.

Jan 1, 1970

By N. Kyriazi

A performance study of oxygen self-rescuers from the United States and other countries was undertaken as an assessment of present worldwide technology. The apparatus were tested a an breathing and metabolic simulator in the Life Support laboratories of the Bureau of Mines. Parameters monitored during the testing were inhaled levels of C02 and 02, inhaled gas temperature, and breathing resistance. The metabolic demand placed on the apparatus represented the average demand of the 50th percentile miner performing a 60- min man-test 4, as described in 30 CFR 11H. Results presented include ;apparatus service life and subjective comments as well as averages and peaks of monitored parameters.

Jan 1, 1984

By P. F. Berry

X-ray fluorescence analytical techniques are fairly well established in the mining and metallurgical industries. In recent years, instruments utilizing radioactive isotopes have been developed which, owing to their more compact size, greater reliability and independence of substantial power supplies, are often preferred to X-ray tube installations. Analyses can now readily be carried out in the field, on the factory floor and in otherwise difficult locations. This paper describes many examples of radioisotope X-ray fluorescence for the analysis of metallic minerals, finished metals and alloys and also for the continuous measurement of metallic coatings, such as tin and zinc, on steel. Radiation scatter techniques are also described for certain analyses and for thickness and density measurements.

Jan 1, 1967

Prof. J. W. Richards, South Bethlehem, Pa. (in reply to several questions):—The cut representing some of the round briquettes which were under test shows that, at the brcaking-stresses, they break into lumps, and do not disintegrate into powder. The process is simplicity itself. I have followed the different processes for sintering iron-ores and flue-dust, am interested in all of them and wish them all success; but this process appealed to me strongly by its simplicity. It is in line with a method which I once tried to work out myself, but which never came to anything, namely, the agglomeration of fine iron-ores by means of Portland cement. As small an amount as 5 or 6 per cent. of Portland cement will enable fine ore to agglomerate and set into a briquette, but when I came to estimate the cost, I found it was a little too high. The Schumacher process, curiously enough, does not work well on iron-ore, but flue-dust thus treated does harden and give a strong briquette. In my attempts to find a reason for this difference, it has occurred to me that possibly the particles of flue-dust had been coated over with some sublimed silica, which might be an agent in the setting. But I found by experiment that neither sublimed silica, nor ordinary silica, nor ordinary alumina, would briquette. Chemically pure iron oxide briquetted quite hard; but the application of pressure is a necessary part of the operation. If simply moistened with the solution and allowed to stand it does not set hard, but the more pressure applied to it the hardcr it sets. Evidently the flue-dust particles must be pressed very close together in order to get the small proportion of active material wet, so that the particles shall act at their points of contact; for it is evident that only at the points of contact does the cementing action take place. The reactions are facilitated by considerable pressure, bringing the acting particles close together, and may go on with

Jan 1, 1913

By G. R. Webber, L. M. Azzaria

"The wide interest in the application of the geochemistry of mercury to mineral exploration is leading to the continued development of a variety of analytical methods for the determination of nanogram quantities of this element. The various methods have different degrees of reliability, sophistication and portability. In this investigation, two simple portable instruments were used in geochemical prospecting surveys -an ultra-violet absorption instrument and a similar one modified with gold for the removal of interfering substances. The results show the application of the method to the determination of mercury in soils of different organic content, and in rocks, sulphides and air."

Jan 1, 1969

By V. R. Burkhart

Pennsylvania Power & Light Company is an investor-owned public utility which was incorporated under the laws of the Commonwealth of Pennsylvania on June 4, 1920, with general offices at 901 Hamilton Street, Allentown, Pennsylvania. At the present time PP&L is operating five coal-fired steam electric stations, two hydroelectric stations and one steam heat plant which is being converted from anthracite to oil fired. In addition, PP&L is a partner in both the Keystone and Conemaugh mine mouth bituminous coal-fired steam electric stations in Central Pennsylvania and also part owner of a company which operates another hydroelectric station. PP&L plants, other than the two mine mouth stations, are located in Central Eastern Pennsylvania. (Figure 1) The company derives about 99% of its operating revenues from supplying electric service, while the balance is from the one steam heat plant serving the city of Harrisburg. The entire service area covering 10,000 square miles in 29 counties, has a population of approximately 2,300,000 people. The area served is mostly suburban. It includes 109 communities each having a population in excess of 5,000 people. The largest cities served are Allentown, Bethlehem, Harrisburg, Hazleton, Lancaster, Scranton, Wilkes-Barre, and Williamsport which range from 50,000 - 120,000 in population. So you see our service area does not include any major cities. The area has industrial, commercial, residential, agricultural and recreational activities that are linked with the Eastern Megalopolis by an extensive interstate limited-access highway system and railroad networks. We consider this Central Eastern Pennsylvania area we serve as the "heart of the market" -- an area with great growth potential.

Jan 1, 1973

By Drummond Earley III

The hydrology of in situ leach mining operations is being studied by the U.S. Bureau of Mines using a variety of techniques, and the Bureau has made significant advances in tracking and modeling the flow of leach solutions in rock formations. However, the influence that leach solution composition has on the hydrology of these systems is poorly understood, and geochemically-controlled changes in the hydrologic characteristic of ore deposits during in situ leach mining of porphyry-hosted, copper oxide ores have not been previously studied. The Cyprus Casa Grande in situ leach mining operation mines fracture-hosted and disseminated copper oxides (predominantly chrysocolla) hosted by granodiorite porphyry using a pattern of underground wells. The injection solution consists of sulfuric acid raffinate from a solvent extraction-electrowinning plant. Chemical analysis of representative injection and recovery solutions reveals that gangue cation concentrations in these solutions are high, and geochemical modeling shows that the solutions are saturated or nearly saturated with respect to gypsum, jarosite, and various amorphous oxides. Precipitation of these solids is evoked by calcium-exchange reactions, rising pH, and perhaps locally rising redox potential, as the leach solution reacts with the ore minerals, host rocks, and the atmosphere. Mass and volume balance calculations show that approximately 25 cm of precipitates are formed per gram of copper recovered at Cyprus Casa Grande. The results of geochemical modeling agree with petrologic examination of pre-and post-leach core samples from the leached horizon. Moreover, hydrochemical modeling and hydrologic field data suggests that chemical precipitation causes significant decreases in porosity and permeability during in situ leach mining of porphyry-hosted, copper oxide ore.

Jan 1, 1992

By H. C. Ko

Calorimetric determinations of low-temperature heat capacities and the standard enthalpy of formation were made by the Bureau of Mines for aluminum sulfide, A12S3. The standard entropy (S°), enthalpy of formation (?Hf°), and calculated Gibbs energy of formation (?Gf°) at 298.15 K are 27.93±0.05 call deg-mole, -155.6±0.9 kcal/mole, and -153.0±1.0 kcal/mole, respectively.

Jan 1, 1976

By Imre Gombköto, Zoltán Pap, Ákos Debreczeni, Sándor Nagy

Eddy current separators have become generally used in waste recycling industry during the last decade. There are many papers dealing with separation processes on eddy current separators, and also many article describes particle trajectory and different particle features affecting particle trajectory. These data are used in modeling as well. Within the frame of R&D project called ‚Fundamental research into the exploitation of the economic development potentials of critical raw materials in international co-operation - CriticEl?, authors are aimed for using Eddy Current Separator (ECS) as a mechanical separation step of high value critical elements recovery of selected WEEE’s like display panels, PCB’s. ECS, equipped with 305 mm wide belt, and a concentric magnetic rotor is used for experiments targeted development of methodology for determining separability of different particles on ECS. The subject of our work was to investigate the behavior of model particles with different shape, conductivity (aluminum and copper), orientation and size in order to separate Al and Cu according to the results of many experiments were carried out in this field. However it looks like that throwing distance of one particle is only possible to describe by a certain distribution for even the same particle within the frame of the same conditions. Sample mean and standard deviation are depending on some of the particle feature and acting forces. The paper is going to draft the first results on the relationship between distribution of throwing distance and particle properties.

Jan 1, 2014

By S. C. Flood, J. D. Hunt

"The columnar-equiaxed transition (CET) has been studied numerically under unsteady-state conditions using mathematical models that: (i) include a non-equilibrium undercooling at the columnar front;and(ii) describe the simultaneous evolution of the columnar and equiaxed zones.The results are discussed and compared with those produced by a steady-state analysis.IntroductionThe majority of the previous work on the columnar-equiaxed transition (CET) has concentrated on the production of equiaxed nuclei, regarding this as being the critical step in the formation of an equiaxed zone. Recently, the growth of equiaxed grains has been considered and this is not unreasonable because, for an equiaxed zone to be present, the grains must grow as well as nucleate. Since the growth rate of the grains will be determined by the thermal environment at and ahead of the columnar tips, it was decided to model the liberation and flow of heat during solidification to discover whether the various trends in the columnar range might be explained by their effect on the temperature profile throughout the casting. The models presented here for the solidification of a casting are the first to include the latent heat liberated ahead of the columnar front. Burden and Hunt (1) consider its effect only qualitatively, and although Lipton et al (2) adopt a criterion for the CET which is based on the thermal interaction of the columnar and equiaxed grains, they do not actually include the latent heat in their calculations.It can be argued that the latent heat liberated by the equiaxed grains in the bulk will retard the columnar dendrites in a casting: once the equiaxed grains are sufficiently well-established, the latent heat that they evolve could slow down the columnar growth to such an extent that the equi axed would dominate. Alternatively, the latent heat produced by the equiaxed grains might suppress further equiaxed solidification by raising the bulk temperature. The nature of the thermal interaction between columnar and equiaxed growth is not obvious, and because it is dependent on the material parameters and the dimensions of the system, it cannot be considered effectively in a qualitative way but has to be studied quantitatively: hence the need for the mathematical models discussed in the following pages. The results of the models are discussed in the light of a steady state analysis."

Jan 1, 1986

By Steven J. Page

Longwall double-drum shearers frequently have difficulty complying with the 2.0 mg/m3 dust standard and, therefore, require the use of effective dust controls. However, before dust controls can be implemented effectively, the major individual dust sources must be determined and their relative severity evaluated. The Bureau of Mines has recently developed a sampling strategy, based upon short-term gravimetric sampling, that can identify the major dust sources contributing to the shearer operator's exposure. This technique utilizes approved gravimetric sampling equipment already available to all mine operators and can be performed by two people in 2 days. Five examples, including data analysis, are discussed with respect to various cutting sequences. In addition, typical dust source contributions obtained from studies of double-drum shearer operations regularly in compliance are included. Mine operators can thereby compare their dust source evaluation results with those from these longwalls.

Jan 1, 1982

By John Malcolm Gray

Interest in X-80 linepipe steels emerged in the early 1980’s and it was first used in 1985 by Ruhr Gas [1]. The early steels were extensions of conventional Nb-V or Nb-Mo microalloyed X-70 steels but other alloying concepts emerged based on Nb-Mo-B alloying (NKSTAF [2] and ULCB [3]). The latter had acicular ferrite/bainitic microstructures and carbon contents below 0.05 percent. In parallel renewed interest developed in ultra low carbon (0.02 percent) higher niobium steels which had first been studied in 1962 [4]. Such steels exhibited excellent notch toughness when processed with high finish rolling temperatures (>950°C) which made them suitable for processing on weak, older rolling mills. With time such steels, designated “High Temperature Processed”, or HTP steels, were further optimized and produced in modern, very strong rolling mills due to their superior economy compared with traditional vanadium and molybdenum containing steels. The chronology of the HTP development is presented in the present paper. Full scale demonstration heats of a 0.06 percent carbon 0.10 percent niobium steel were produced by Bofors Steel Plant in 1972 and were converted from slabs to plates by nine different steel mills [5-7]. Commercial application in API Grade X-70 first occurred in Canada in 1974 [8,9] but the concept was only used sporadically after that until 1998 when it was applied for the API Grade X-70 Sour Service Cantarell Project [10] in Mexico. Soon thereafter, the El Paso Cheyenne Plains Project used a 0.05%C 0.095%Nb 0.27%Cr variant of the HTP steel [10-12]. Nowadays the HTP concept is being utilized for construction of approximately 6000 km of 48” OD x 18.4 mm X-80 per year in China. The metallurgical principles and history of the development are presented in details in this paper.

Aug 7, 2018

By John S. Stevenson

THE Twin "J" Mine, operated by Twin "J" Mines, Limited, represents an amalgamation of the old Lenora, Tyee, and Richard III mines (see Figure 1) on mount Sicker, eight miles by road, northwesterly, from the city of Duncan, on Vancouver island. These mines produced 253,000 tons of copper-gold ore between 1898 and 1909 (see Table I). During the more recent period of production from these properties, July, 1943, to May, 1944, Twin ?J? Mines, Limited, mined and milled ore with values mainly in copper and zinc, and minor values in gold, silver, and lead. Figures are not available for this later production. Field work at the property was started by the writer in 1941 and continued in 1943 and 1944.

Jan 1, 1945

By CHARLES W. BENTON

THE following paragraphs comprise such information as the Secretary has been able to obtain concerning the members and associates whose deaths have been reported. Further particulars or corrections of errors, and biographical data concerning deceased members or associates not already noticed in this way, are solicited. Charles IV. Benton was born at Kezar Falls, Maine, Nov. 12, 1843. We have no accurate knowledge concerning the early part of his career. In 1871 he engaged with the N. Y. Honduras Rosario Mining Co., at San Juancinto, Honduras, C. A., and later was employed at the Monserrat mine at Yuscaran, and at Santa Lucia, Honduras, with the Tenero Mining Milling Co. of Pennsylvania. In 1897 he became a member of the Institute. At the time he was stricken with his last sickness he was employed at the Paymaster mine at Tucson, Ariz. He died at Fairmount, Denver, Colo., Sept. 9, 1907. William R. Boggs, Jr.-The notice in the Bulletin for January was incorrect in saying that the murder of Mr. Boggs occurred while he was employed as metallurgical. manager by Mr. W. B. A. Dingwall, at La Maroma, San Luis Potosi, Mex. Mr. Dingwall writes that in March, 1907, Mr. Boggs left him, to return to his home at Winston, N. C., whence he. subsequently went to Durango, Mex., to take, with the Topia Mining Co., a position which he occupied at the tine of his death, Nov. 17, 1907. Mr. Dingwall says that, while in his service, Mr. Boggs never had any trouble with the workmen, but was esteemed and liked by them, as by all who knew him ; and adds, injustice to the State of San Luis Potosi, that the population, even in the mining-camps of that State, is orderly and law-abiding, and that the authorities are vigilant and just. Our

Mar 1, 1908

By P. R. Taylor

Laboratory experiments have been performed to evaluate the kinetics of roasting pyrite and arsenopyrite in air at elevated temperatures, in the presence of lime. The effects of temperature, time, air flow rate, particle size, lime type, and mineral/lime weight ratio on the rates of oxidation, lime sulfation, and lime arsenation were studied. The reaction products were identified using chemical analysis, x-ray diffraction, SEM analysis, and optical microscopy. The results are discussed in terms of the utilization of lime to capture sulfur and arsenic during the roasting of refractory precious metal concentrates. More than 99.9% of the arsenic and 98% of the sulfur are contained when roasting pyrite and arsenopyrite with hydrated lime under typical roasting conditions.

Jan 1, 1991

By V. N. Mackiw, H. Veltman

"A process is described which permits the separate recovery of lead and zinc from complex low-grade sulphide concentrates such as are produced from the New Brunswick type of disseminated pyrite ores. This process calls for the preparation of a lead-zinc bulk concentrate from the original ore by flotation. The bulk concentrate is then oxidized under pressure in autoclaves in aqueous sulphuric acid solution, such as return electrolyte from zinc electrolysis. This yields a zinc sulphate solution and a residue containing lead sulphate, unaltered pyrite and elemental sulphur generated during the oxidation. After the oxidation, the leach slurry is briefly heated to above the melting point of elemental sulphur and then cooled. Thus, pellets containing pyrite and elemental sulphur are formed, and they are separated from the lead sulphate by screening and/or flotation. Laboratory tests have shown that about 95 per cent of the zinc and lead can be separately recovered from complex bulk concentrates. Process possibilities are discussed."

Jan 1, 1967

By E. Taskin

Diasporic bauxite from the Mugla-Milas region was mechanically activated in a planetary mill for different activation times and the structural changes were examined by X-ray diffraction analysis (XRD), scanning electron microscopy (SEM) and specific surface area analysis (BET ? Burnauer, Emmett and Teller). Non-activated and activated bauxite samples were leached directly in alkaline (Na2O) solution at atmospheric conditions and the activation procedure led to the amorphization and structural disordering of the diasporic bauxite structure, which increased the dissolution efficiency. Effects of milling speed, liquid/bauxite ratio and leaching time on alumina extraction in direct alkaline leaching of diasporic bauxite were also studied. The alumina extraction was ~7% for non-activated bauxite and ~70% for activated (75 minute) bauxite. Key words: Diasporic bauxite, Mechanical activation, Alkaline leaching, Alumina extraction

Jan 1, 2009