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By H. S. Drinker

THE first discovery of zinc 011 the property now worked by this company was made by the celebrated mineralogist, Prof. William Theodore Rapper, in 1845. Different claimants kept the property in continual litigation till 1861, when everything was satisfactorily settled by the purchase of the land by the company, who have worked it ever since. The mines are situated in a valley, four miles south of Bethlehem, Pa., in Lehigh County. The valley is from two to three miles broad, and is bounded 011 the north and south by syenitic hills. Syenite underlies the valley, and upon this is deposited the Potsdam sandstone, then a layer of slate, and, finally, a dolomitic limestone, belonging to the Chazy or Black River formation, in which the zinc deposits are inclosed. The rocks occur in folds, and have evidently been subjected to tremendous pressure from below, the zinc deposit being found in an anticlinal axis, in nearly vertical veins. I t is supposed that the zinc was originally disseminated through the

By R. T. Hukki

THE accepted basis of comparisons between mills of different diameter is the percentage critical speed. [ ] In the following analysis capacity, T, is expressed in short tons per hour, tph, and power consumption, P, in kilowatts, kw. Accordingly power consumption per unit of capacity, Po, will be expressed in kilowatt hours per short ton, or kw-hr per ton. In all equations D refers to the inside diameter of the mill in feet and v to the peripheral speed of the mill in feet per minute inside the liners. Comparison between separate mills must be based on equivalent grinding conditions, i.e., same feed, same size distribution of feed, same size distribution of product, and same percentage of solids. In addition, comparisons between separate rod mills must be based on the same rods, same type of liners, and same percentage rod load. Comparisons between separate ball mills presuppose the same balls, similar liners, and same relative ball load. The practical np-range through which the equations apply varies, being narrower for fine grinding in ball mills and wider for coarse crushing in rod mills.

Jan 7, 1954

By M. R. Wormald

A real time data acquisition system has been developed for implementing standard radiometric analytical techniques, applied to the monitoring and control of mineral processing plants. The system uses standard ECB-bus microprocessors and peripherals, in conjunction with a specially designed nucleonic pulse ADC. It is being applied to the accurate on-line analysis of naturally-,occurring radioelements in processing plants, for example by simultaneously measuring the intensity of 1.46 MeV gamma-rays from the naturally-occurring radioisotope K-40, and the stream density by gamma-ray transmission of 662 keV gamma-rays. Gain stabilisation of the NaI(T1) scintillation detectors is maintained by the microprocessor in slave units, each of which may control up to four sample presentation systems. Data analysis - including corrections for bulk density, radioactive decay of the Cs-137 gamma-ray source, pulse pile-up, dead time and external background - is carried out in a master computer which is connected to the slave unit, and can be interfaced to the plant control computer via data links.

Jan 1, 1986

By Y. Yang, M. Zhang, X. Xia, S Shi, Z. Shen

A stepwise arrangement of flotation cells is the most common layout of a flotation circuit in the mineral processing industry. In such a design, slurry flows from upstream to downstream by means of gravity, and the middling products are returned to previous stages by pumps. This paper will introduce an alternative solution in which the forced-air and slurry-induced flotation cells are adopted so that all the flotation cells can be placed on the same horizontal platform and no pumps will be needed for middling product transferring. The technology of the forced-air and slurry-induced flotation cell will be described in detail, including unique features, the working principle and the related fundamental problems. The comparison of capital investment, operating cost and metallurgical performance will be made between the conventional stepwise arrangement and the samelevel arrangement technology based on industrial practice. Keywords: Forced-air and slurry-induced flotation cell, same-level arrangement, stepwise

Jan 1, 2020

By Ejike Emmanuel, Nwoye Chukwuka, Ogwuegbu Martin, Asuwaji Ayuk, Onyedika Gerald

"Microwave pre-treatment of cassiterite ore prior to leaching was carried out in an attempt to obtain high grade of Sn02 and to conserve the total energy expended during processing. Microwave treatment was selected due to the presence of associated minerals which behaves differently to microwave energy. Studies in this work showed that microwave pretreatment of cassiterite ore can be applied to increase the recovery of tin oxide within 5 minutes of leaching. Microwave treatment of the ore resulted in mineral liberation at all particle sizes. Tin oxide was separated from the major impurities via leaching in potassium hydroxide solution and precipitation, resulting in 98% Sn02 at pH 7.IntroductionIn the nineties, the available techniques used for ore processing and analysis in Nigeria was the solution methods of either alkaline fusion or acid digestion [1,2]. A process in which cassiterite is made acid soluble by reduction to SnO2 , which stabilizes by glass formation and the tin was extracted by leaching the glass with sulphuric acid, followed by electrowinning was reported [3,4]. In another study, Baba et al [5] studied the dissolution kinetics of a Nigerian casiterite ore in hydrochloric acid solution. The effects of acid concentration,temperature, particle size and stirring speed were examined. It was found that the dissolution rates of cassiterite depends on hydrogen ion concentration, H+, stirring speed and ore particle dimensions. These were believed to report low data due to incomplete solubilization of the ore minerals in aqeous medium [6]. Analytical chemists have used microwave heating devices routinely for the dissolution of metals, minerals and various chemical products in chemical analysis [7,8]. It offers faster heating rate and consequently faster dissolution rate than conventional heating. The principle of the dissolution of analytical samples has been applied to the leaching of various minerals contained in an ore or concentrate sample. Some researchers [9, 10] conducted microwave assisted leaching of laterite ores containing oxides of nickel, cobalt, and iron. The metals of these mineral components were converted into their chlorides by microwave heating (1200 W, 2450 MHz, Nz atmosphere) a mixture of the ore and ammonium chloride between l 77°C and 312° C for 4-5 min, followed by water leaching at 80° C for 30 min. Nickel and cobalt extractions were 70% and 85%, and respectively, and are comparable with roasting at 300°C in a conventional rotary kiln for 2 hours."

Jan 1, 2013

By L Gobbo

X-ray diffraction (XRD) provides useful information about the composition of an ore sample in terms of quantification of crystalline phases and amorphous content. The use of new, fast detection systems implemented in CubiX FAST industrial diffractometers creates the opportunity to use this technique in exploration and modern process control. Besides the chemical composition of iron ores, their phase composition is also an important factor for exploration, quality control and processing. In the analysis of iron ore, XRD can identify the phases containing iron, such as haematite Fe2O3, magnetite Fe3O4, and goethite FeO(OH), and any other mineral phases present, especially silicas. Quantitative analysis is possible by various classical methods such as straight line or polynomial calibration with standards, but modern quantification analysis techniques such as Rietveld analysis or full pattern autoscale analysis are attractive alternatives, as they do not require any standards. These methods offer impressive accuracy and speed of analysis. Another analysis technique offering great benefit to ore exploration and process control is cluster analysis. This technique greatly simplifies the analysis of a large amount of data, eg from drill core samplings, and automatically sorts closely related scans of an experiment into separate clusters and marks the most representative scan of each cluster as well as outlying patterns. This can facilitate multi-dimensional compositional mapping of ore deposits, identifying regions of favourable mineral composition and allows fast and reliable tracking of the process. It is the most economic procedure to have automatic data evaluation without involving any dedicated personnel in the process. Details of the techniques used, sample optimisation methodologies, results, data precision and limitations will be discussed. The approaches have enormous potential as an inexpensive, reliable tool, useful in the characterisation of iron ore materials in an industrial environment.

Jan 1, 2009

By Hanns J. Billmayer

Optimized Operator Compartment layouts based on previous Bureau of Mines activities in standardization and optimization of controls were designed and installed in three operating vehicles. Two National Mine Service 48A-36 TorKars were modified in production prior to delivery to the Quarto Mining Company. An Elkhorn AR-4 scoop owned by Adanac Coal Company was modified in a local rebuild shop. The modified vehicles were then evaluated underground under normal production conditions for a 60 day period. Vehicle operators and management appear well satisfied with the compartment modifications.

Jan 1, 1976

By A. G. Guy

IN the course of a research on steady-state diffusion it became necessary to make diffusion calculations for a finite solid. This problem was found to be sufficiently different from the corresponding problem for the semi-infinite solid for an entirely new approach to be necessary in obtaining a useful solution. The assumption of an exponential variation of the diffusion coefficient with concentration' was no longer a practical necessity, so that the new solution offered the possibility of handling diffusion in semi-infinite solids for arbitrary variations of the diffusion coefficient with concentration. In discussing the principle on which this method of calculation is based, it is convenient to consider the relatively simple problem of one dimensional diffusion into a matrix that initially contains none of the diffusing substance. The solution of the set- ond Fick Law,?C/?t=D0?2C/?x2, for diffusion into a semi-infinite solid is3 C/C=1-F(x/2vD0t [1] where C is the concentration of the diffusing substance at a depth x cm below the surface after dif- A. G. GUY, Member AIME, and M. GOLOMB are Professor of Metollurgicol Engineering and Professor of Mathematics, respectively, Purdue University, Lafayette, Ind., A. S. YUE, formerly with Purdue University, is now with the Research Laboratory, Dow Chemical Co., Midland, Mich. TP 4505E. Manuscript, July 18,1956. fusion has occurred for t seconds; C, is the concentration of the diffusing substance at the surface of the matrix; Do is the diffusion constant, expressed in sq cm per sec; and + represents the Gauss error function. The corresponding solution for diffusion into a finite solid of thickness, 1, is conveniently written for the change in concentration, C+, at a point midway through the matrix and for times, t, great enough for the following equation to be used4 c1/2/C1=(1/2-2/?e-?2D0t/l2) [2] In Eqs. 1 and 2 the diffusion coefficient is represented by the symbol Do (rather than by D) to emphasize that these equations are valid only for constant values of D. To understand how these equations can be modified to take account of actual variations of D, such as that shown in Fig. 1, first consider the fact that for a given time of diffusion theconcentration at a given point is determined, not by the D value alone, but by the ratio x/vD0 in Eq. 1 and by a similar ratio, l2/D0 in Eq. 2. Even though in fact D varies, it is possible to keep this ratio constant by using a special coordinate system, x,, that varies with D in the appropriate manner. The necessary character of this special coordinate system can be easily visualized by imagining that

Jan 1, 1958

"A sulfide ore containing 2.19 g/t Au and 13.13 g/t Ag was studied for the deportment and extractive metallurgy of pay metals. The ore is composed mainly of non-sulfide minerals with approximately 10% pyrite and minor amounts of marcasite, chalcopyrite, galena, sphalerite, and arsenopyrite. The deportment study using a comprehensive approach showed that gold and silver minerals in the ore are mainly native gold (Au), electrum (Ag, Au), petzite (Ag3AuTe2), hessite (Ag2Te) and volynskite (AgBiTe2) with minor amounts of acanthite (Ag2S) and argyrodite (Ag8GeS6). At current grinding fineness (P70@150µm), the majority of liberated native gold and electrum particles are larger than 20µm with 85% >40µm, some of them are even larger than 150µm, indicating that extended leach time may be required to dissolve these coarse gold grains to completion and gravity concentration needs to be considered. Petzite is relatively fine with all liberated particles being less than 80µm in size. Gold distribution and leach testwork results showed that liberated gold accounts for 50% of the head assay, exposed gold associated with sulfide and non-sulfide minerals accounts for 30% and 11% of the head assay, respectively. Gold locked in sulfide and non-sulfide accounts for 4.8% and 4.1%, respectively. Thus, it is recommended that cyanide leaching be considered for extracting gold in this ore. This paper presents the detailed results of the gold and silver deportment study and extractive metallurgy testwork, and discusses the impact on process selection and flowsheet development.INTRODUCTION Gold and silver have been found in various geological environments and ore types. In terms of the gold deportment and extractability, gold ores can be classified into two categories and 12 types. Their extractive metallurgy is largely driven by mineralogical factors such as particle size, association with other minerals, coatings and rimmings, presence of cyanicides, oxygen consumers and preg-robbers, presence of refractory gold minerals and locking of submicroscopic gold in sulfide and sulfarsenide mineral structures (Zhou et al., 2004; Marsden & House, 2006; Zhou, 2013a, 2013b). Compared to gold, silver mineralogy is more complex and metal extraction is more challenging due to its presence in over 200 Ag-bearing minerals (a silver-rich ore body would typically contain 5 to 10 different silver minerals) (Gasparrini, 1984), presence of refractory silver minerals (such as pyrargyrite, prustite and stephanite) and submicroscopic silver in sulphide minerals (such as galena and copper minerals) (Chryssoulis et al., 1985; Di Prisco et al., 2002). The presence of these issues often causes problems in Ag-bearing ore processing. Therefore, knowing the deportment of gold and silver in the ores and metallurgical products is important for flowsheet development and process optimization."

Jan 1, 2018

By B. P. Simser, R. K. Brummer, A. Mortazavi, P. P. Andrieux

"A large-scale panel destress blast was fired at Brunswick mine in the fall of 1999 in order to reduce the ground stresses in a critically important neighbouring mining region. This work, sponsored by the Mining Division of CAMIRO and Brunswick mine, consisted in heavily choke-blasting — and subsequently leaving in place — a massive waste sulphide pillar in the southwest end of the 1000 m level. This paper describes the approach and design methodology used to try to maximize breakage in the rock mass in the area to destress, while minimizing damage to critical infrastructures in the vicinity. The loading operations, as well as the results of the blast — in terms of its field performances, as recorded by near-field blast vibration monitoring equipment, visual postblast assessments and measured impact on the regional stress field — are discussed as well. A brief comparison between the measured stress changes and inelastic numerical modelling of the test site is also presented.Un tir à grande échelle de relâchement des contraintes dans un pilier a été effectué à la mine Brunswick à la fin de l’automne 1999 dans le but de diminuer les contraintes de terrain dans une très importante zone de production adjascente. Ces travaux, financés par la division minière de CAMIRO et la mine Brunswick, consistaient à tirer violemment sans aucune face libre, et à laisser en place, un pilier de sulphures massifs au sud-ouest du niveau 1000 m. Cet article décrit l’approche et la démarche conceptuelle utilisées pour tenter de maximiser les fractures dans le pilier visé, tout en minimisant les dommages collatéraux à des infrastructures critiques se trouvant dans les environs immédiats. Les opérations de chargement des explosifs et les résultats du tir — en termes de ses performances, telles qu’évaluées par de l’équipement de monitoring rapproché des vibrations de tir, d’observations visuelles, et de son impact sur les contraintes de terrain locales — sont également discutés."

Jan 1, 2003

The purpose of this paper is to provide some practical commercial advice in relation to issues of access and trespass during exploration. It is not my intention to provide a detailed analysis of the applicable law because this is not the appropriate forum for latin maxims and turgid case studies. Instead I will explain the issues in sufficient detail to enable those who are not familiar,with the legal concepts to understand their obligations and responsibilities in relation to exploration activities. Take as an example a situation where a company (for the sake of attempted light relief, called Rogue Mining) holds an exploration tenement adjacent to one held by Lamb Exploration. In conducting aerial exploration activities over its own tenement Rogue overflies the tenement held by Lamb, doesn't turn off its equipment and accidentally collects data in respect of the adjacent land. In analysing that data it becomes apparent to Rogue that there is a substantial anomaly on the adjacent land of which Lamb is apparently unaware. Rogue subsequently negotiates to purchase an interest in Lamb's tenement.

Jan 1, 1995

By D. N. Tallman

The electrokinetic properties of MgO have been utilized to simultaneously filter suspended solids and remove trace amounts of dissolved heavy metals from synthetic mine water. Greater than 95 pct removal of metals from influent at neutral pH containing 1 to 6 mg/L of dissolved Cd, Cu, Mn, Ni, and Zn can be routinely achieved by filtering through a granular bed of MgO at flow rates typical of rapid sand filtration (0.3 cm/s). Filtrate concentrations of most metals can be maintained below 0.1 mg/L for 160 bed volumes or more loading. The more mobile metals (those with larger solubility products) are more difficult to remove, and are strongly bonded to the MgO granules so that chemical stripping with chelating agent is required to clean the bed. Less mobile ions are easily removed by the filter and are effectively stripped by conventional filter backwashing. The fraction of metals recovered by chemically stripping the loaded MgO filters correlates to the zero points of charge of the metals. This process may be applicable to removal and recovery of trace amounts of heavy metals in mine drainage that is partly neutralized by liming. Also, since many of these metals are critical and strategic, the technique can be adapted not only to recycle process water from mineral and milling waste streams, but also to reclaim their metal values.

Jan 1, 1986

By Merwin Bernstein

Peru has been an important source of metals since Aug. 29, 1533. On that day Francisco Pizarro took charge of the 24 t (772,000 oz) of gold and silver that constituted Atahualpa’s ransom. At today’s prices, the value of that booty ranges between $100 and $150 million, depending on the proportion of gold to silver. Since then, Peru’s silver and gold production has been legendary. Current mine production Most of Peru’s metals are mined from the Andes Mountains and its foot-hills. The Andes run the length of the country parallel to the Pacific coastline from Ecuador to Chile, a distance of nearly 3000 km (I 875 miles). They are about 300 km (187 miles) wide and much of the range is more than 3000 m (9900 ft) in elevation. High plateaus (altiplanos) occupy a large part of the range. Both flanks are rutted by large valleys and canyons. Many of these peaks are prodigious. which make road building expensive and adds to the cost of mining.

Jan 1, 1993

By J. M. Camp

In conforniity with the design of the oficials of the United States Steel Corporation for the standardization of the methods employed in the sampling and analysis of all materials encountered in their various lines of manufacture, the Chemists' Committee presents this compilatioti of standard methods for the sampling and subsequent analysis of molten pig-iron. In selecting the methods, the Committee employed the same line of procedure as in former cases, viz., the careful consideration of all the methods employed in each laboratory of the Corporation, evolving therefrom the several methods herein described, the immediate adoption of which is desired. The services of Messrs. W. B. N. Hawk, William Brady, and C. H. Rich, a sub-committee appointed for the preparation of the present paper, are gratefully acknowledged. II. Introduction. A quite obvious cause of nonconformity of results of comparative analyses in the various laboratories of the Corporation has been an apparent lack of uniformity of method in the sampling and analysis of molten iron. This condition is particularly apparent with regard to the determination of the sulphur, numerous discrepancies in which would appear t.o indicate the absence of, and the necessity for, some uniform method of procedure. The estimation of the

Jan 1, 1913

By John Nell, Paul den Hoed

Carbochlorination tests were conducted with matched particle-size fractions of rutile, ilmenite and high-titania slag in a small bubbling fluidized-bed reactor. The effects of temperature, the type and proportion of solid reductant in the charge, and the fraction of Cl2 in the fluidizing gas were investigated. Tests confirm the need for solid carbon in the bed if chlorination is to run at high rates. With solid carbon in the bed, CO supplied with the fluidizing gas does not increase significantly the degree of chlorination after 75 minutes. Ilmenite is chlorinated more quickly than titania slag, which in turn is chlorinated more quickly than rutile. Rates of chlorination at 1100°C and 1000°C are much the same and significantly higher than at 900°C. Chlorination is associated with significant increases in particle porosity (even for rutile), which is brought about by the rapid initial chlorination of FeO and MnO (in ilmenite and slag) and (it is argued) by the chlorination of Ti2O3 which forms at high-energy surface sites. A reaction mechanism is presented; where possible, its validity is demonstrated by the support of empirical observations.

Jan 1, 2003

By Charles W. Huggins

A study of the high magnification of some inorganic fibers which are found in nature or produced in the laboratory, has been conducted with the electron microscope. This series of electron microqraphs shows the important morphological differences exhibited by potassium-lead silicate, lead-aluminum silicate, chrysotile, wollastonite, silicon nitride, potassium titanate, cobalt chrysotile, magnesio-fluor-richterite, fluor-richterite, refractory oxide fiber, silicon carbide, massive serpentine, and palygorskite. A ribbon or a thin lath 250-2500 A. wide is the structural form of potassium-lead silicate and lead-aluminum silicate. Chrysotile, cobalt chrysotile, and massive serpentine all have a tubular structure and a fairly uniform (150-300 A.) diameter. Wollastonite, potassium titanate, fluor-richterite, and magnesio-richterite crystals have a lath shape, and potassium titanate laths are laminated ribbons. Single fibers of silicon nitride and palygorskite are ribbons, and the silicon nitride sample contains many twins (branching fibers). Palyqorskite fibers are highly flexible and have cross-sectional measurements of 150-300 A. Silicon carbide fibers differ from other fibers because their structure consists of several different forms. The sample used in this study had, predominately, a margarite-type structure. The refractory oxide fiber lost, all its apparent fibrosity after being prepared for electron microscopic examination, and only irregular fragments are visible in the electron micrographs.

Jan 1, 1962

By Marco Olper

After two years of extensive research a new and innovative modification to the CX-EW process has been exploited. This process, called CX-EWS, avoids completely all the critical aspects of the previous process which affected the cost of the energy, of the chemicals and of The maintenance of the insoluble anodes. All these benefits reflect a saving of about 30% of The operating costs compared to the present traditional production and allow for a total operating costs of less than 6.5 cts/lb. lead (net of raw material cost). With this new technology it is allowed for the first time the treatment in the same plant facilities of both primary lead sulphide concentrate and spent batteries. The paper describes the technical and economical aspect of the new process with a feasibility study for 150,000 t/y spent battery facility throughput.

Jan 1, 1995

By S. F. Turcotte, B. J. Grierson

At the Q. I. T. ilmenite smelter, nine electric furnaces produce titania slag and iron At high power levels, a furnace requires either a slag or an iron tap approximately once an hour, using rail cars as slag receptacles and ladles for iron. The correct scheduling of taps is an important operational tool due to peak power load and operational considerations. Over recent years, large increases in furnace capacity have imposed severe strains on the product handling facilities. This situation results in loss of production when several taps are bunched, because of an in- ability to handle many taps simultaneously. An on-line computer program has been developed to generate schedules for tapping a single furnace. By improved scheduling, this program can en- large the tonnage of each tap and minimize the number of taps, while reducing traffic congestion and unit cost s. Future plans call for extension of this technique to all nine furnaces with addition of a master scheduling program to optimize the overall traffic flow in the smelter aisle.

Jan 1, 1969

By C. B. Davison

One goal of the Bureau of Mines is to conserve the Nation's mineral resources by developing improved performance materials. Consistent with this goal, the Bureau conducted studies on the formation of undesirable cristobalite in seven different fire clays used as refractories. The studies employed scanning electron micrography, chemical and X-ray analyses, and pyrometric cone equivalent determinations to examine the sample clays and determine the effect of thermal history and stablilizing additives on the amount of cristobalite in various calcines. This research has indicated that as fire clay calcining temperatures increased from 1390° to 1,490° C there was a gradual decrease in the percent of cristobalite present in the calcines and a progressive development of mullite crystallization. No cristobalite was found in fire clays calcined above 1,550° C, but cristobalite reappeared when the calcines were reheated to temperatures between 1,400° and 1,500° C. The research also revealed that additions of lithium fluoride (LiF) prevented formation of cristobalite in fire clay calcines.

Jan 1, 1979

The hoisting system at the Newcrest Telfer mine is designed for a final duty of 7.35 million tonnes per annum at a hoisting distance of 1450 m. In terms of hoisting capacity (t/h) times hoisting distance it is one of the largest friction hoist installations. Initially, the hoist will be equipped for hoisting 6.5 Mtpa from 1100 m depth. This new drive technology is now well proven by ABB for mine hoist applications with the first installation in commercial operation since July 2001. To date 17 systems for medium voltage drives and another five for low voltage drives have been purchased from ABB for mine hoists. This paper will also deal with skip design and powerful data loggers with diagnostics for local and remote monitoring that are installed in the Telfer mine hoist.

Jan 1, 2005