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By T. R. Ellis

The vast majority of valuations produced for mineral properties using the net present value method provide an estimate of investment value or use value. Such an estimate can be a long way from the price that the property would actually sell for if placed on the market. Indicators from the market need to be used to validate or modify the net present value calculation if market value is being appraised. The comparable sales and replacement cost methods used in the appraisal of urban buildings generally fail when used in the appraisal of mineral properties. Other methods of sales analysis are introduced. Guidelines for what a minerals appraisal report should contain are presented.

Jan 1, 2002

By L. Andrews

Keywords: mineralogy, phase-chemical, chemical-looping combustion, XRD, SEM, EDS, QEMSCAN, PGM, slag, matte, ilmenite Mineralogy, traditionally associated with concentrator studies, is being increasingly applied to problems in pyrometallurgy. Such investigations commonly make use of a number of techniques, and the results are combined for a meaningful interpretation, which can lead to a successful solution. Mineralogical applications are described from pyrometallurgical operations. Examples are given of studies and investigations involving mineralogy in chemical-looping combustion, feed monitoring to platinum-smelting furnaces, and losses to slag in base metal and platinum smelting.

Jan 1, 2011

By L. C. IlsLey

The cool drills that have received the approved of the Bureau of Mines may be divided into three general classes: (1) Hand drills, small drills that are held in the hands or supported against the body while in use; (2) post drills, drills that are too heavy or powerful for hand operation and therefore require some mechanical mounting when in use; and (3) drilling machines. Besides these three classes, drilling equipment has been incorporated in the design n of a number of permissible coal-cutting machines, but such drills are considered an integral part of the cutting machine and are not given separate approval. The hand drills have been described in Report of Investigations 3363, which is cite of several papers that have been published dealing with miscellaneous types of permissible motor-driven mind equipment not covered in bulletins. The present paper describes post drills and drilling machines approved by the Bureau of Mines up to July 1, 1937.

Jan 1, 1938

By L. C. IlsLey

[The cool drills that have received the approval of the Bureau of Mines may be divided into three general classes: (1) Hand drills, small drills that are held in the hands or supported against the body while in use; (2) post drills, drills that are too heavy or powerful for hand operation and therefore require some mechanical mounting when in use; and. (3) drilling machines. Besides these three classes, drilling equipment has been incorporated in the design n of a number of permissible coal-cutting machines, but such drills are considered an integral part of the cutting machine and are not given separate approval. The hand drills have been described in Report of Investigations 3303, which is cite of several papers that have been published dealing with miscellaneous types of permissible motor-driven mind equipment not covered in bulletins. The present paper describes post drills and drilling machines approved by the Bureau of Mines up to July 1, 1937.]

Jan 1, 1938

By Roderick G. Eggert, John E. Tilton

During much of the 1970s and 1980s, world metal consumption grew more slowly than during the 19505 and 1960s. The slowdown contributed to surplus capacity and low real prices because actual consumption was consistently less than expected as new mining and mineral processing capacity came on stream. Over the last year or so, however, world metal consumption has picked up noticeably, raising the question, Has metal demand returned to the long-run growth rates more typical of the 1950s and 1960s than of the 1970s and 1980s? This paper examines this possibility and, more generally, assesses the factors that will shape demand for the major metals over the longer term. TRENDS IN METAL CONSUMPTION The extent to which metal consumption has recaptured the brisk growth rates typical of the 1950s, 1960s, and early 1970s is shown in Figure 1. This figure traces the consumption of crude steel, primary aluminum, refined copper, refined lead, and refined zinc between 1960 and 1987 for the western world, consisting of the OECD countries (including the United States), and the developing countries. Consumption increased in 1987 for all five metals, and preliminary data for the first six months of 1988 suggest even more substantial increases, at least for the United States (U.S. Bureau of Mines, 1988). However, Figure 1 also shows that the recent increases in consumption are not untypical of similar surges during earlier periods of economic expansion and thus may reflect only cyclical or temporary factors. In short, the available data are unable to provide a clear indication of whether recent increases in metal consumption reflect the beginning of a new era of faster growth or simply a cyclical and temporary upturn associated with the expansionary phase of the business cycle. Consequently, to pursue this issue, we are forced to examine the underlying forces that will shape metal demand trends over the next decade. The approach we have taken involves two steps. The first examines the prospects for overall economic growth. The expectation is, the faster the economy expands, the faster the production of metal-containing goods grows.2

Jan 1, 1989

By H. K. Lin

During slow-cooling crystallization of iron-making blast furnace slags, most rare-earth elements in the feed recrystallize as cerite-calcium while scandium and europium concentrate in a sheet-like "mineral". The mineralogy of this "mineral" is studied with one of the objectives being the extraction of the "mineral" from the slag for recovery of Sc and Eu. This "mineral" has been identified as one of the mica group minerals and can be named as rare-earth-bearing barium fluorophlogopite. The mineralogical characteristics of this "mineral" are investigated and discussed. This "mineral" can be effectively recovered from the slag by flotation with dodecylammonium acetate or a combination of dodecylammonium acetate and sodium oleate as a collector.

Jan 1, 1996

By D. W. Frommer, M. M. Fine

Laboratory investigations have produced flotation concentrates contain- ing 91 to more than 92 percent titania, with fair recoveries, from the Christy property, Hot Spring County, Ark. The titanium-bearing ore on the Christy property occurs in a quartz-clay- iron oxide mineralization, which contains, on the average, about 6.0 percent TiO2, chiefly as the mineral brockite; brookite and rutile are different crys- talline forms of titanium dioxide. Recent work by the Bureau of Mines has shown that titanium chloride can be produced readily from the rutile-type mineral by reduction with coke fol- lowed by low-temperature chlorination. Metallic titanium is in turn derived etallic from the chloride by the Kroll process .

Mar 1, 1952

By D. Chakraborty, Neeraj Kumar

"The study provides the comparative analysis of the performance of water only cyclones and hydrocyclone for iron ore fines processing at Joda Iron ore processing plant, Tata Steel. Joda iron ore deposits have higher proportion of kaolinite in the finer fractions and are meant to be separated with cyclones. The iron processing flowsheet of Joda comprises of water only cyclone for beneficiation of iron ore fines. Water only cyclones are used for the beneficiation of fines in the iron ore processing industry and have a larger cone angle compared to that of conventional hydrocyclones to enhance the density effect in the separation. They are aimed to achieve better product quality of underflow however; the desired result could not be achieved at the Joda processing plant. The water only cyclones were operating at the corrected cut-size of about 60 micron with an imperfection of 0.40 and water split to underflow was approximately 10%. The overall Fe recovery from the water only cyclones were 60%. Since the quality of fines produced from the water only cyclone couldn’t be improved, an attempt was made to process the fraction in the conventional hydrocyclone to achieve the desired product quality. The trial results indicated better product quality with the Fe recovery of 72% at corrected cut-size of 70 microns and imperfection of around 0.29. In view of above results it was recommended to replace the water only cyclones with hydrocyclones to achieve higher product quality of about 60% Fe content.INTRODUCTION Water only cyclones were installed at wet plant, Joda to process the classifier fines where the cyclone underflow is considered as concentrate and overflow is discarded as slime. Because of the lower capacity of the cyclones 30% of the classifier overflow was bypassed directly to thickener. Apart from this the quality of fines produced from the water only cyclone couldn’t be improved further hence an attempt was made to process the fraction in the conventional hydrocyclone to achieve the desired product quality and quantity. Hydrocyclone was installed at Joda after replacing stub-cyclone and came into operation on 23rd Aug’ 2017.The process variables of water only cyclones and hydrocyclones are tabulated below:"

Jan 1, 2018

By C. W. Davis

"A copper-palladium-gold-silver ore is being mined at Salt Chuck, Prince of Wales Island, Alaska, from which a concentrate is produced that contains 40 to 50 per cent copper, and considerable amounts of palladium, gold and silver. There has been much difficulty in obtaining assays for palladium, gold and silver from the mine, smelter, sampler, and umpire that check within reasonable limits. While the results for copper content have not been unusual, the results for palladium have varied as much as 0c8 oz. on 3 oz. material, results for gold differed by 0.1 oz. on 1.6 oz. materials, and for a silver content of 7 oz., results differed by as much as 4.0 oz.The Bureau of Mines was requested to determine the causes of variation in the results of the different assayers, and to develop a satisfactory procedure for analyzing such ore.Three samples of concentrate were received for analysis, two small lots that had previously been assayed by the various laboratories, and one large sample. The large sample was dried and ground in a ball mill, put through a 150-mesh screen, and then returned to the ball mill for thorough mixing. The small samples were ground to pass a 150-mesh screen and then mixed on a mixing wheel.The large sample (No. 1) was analyzed by five different procedures, one of the small samples (No.2) by three procedures, and the other (No. 3) by two procedures (the two small samples being too small for further tests). The different procedures tried and the results obtained arc presented below. The samples of concentrate were from ore mimed and milled by the Alaska palladium Co. at Salt Chuck."

Feb 1, 1926

By Thomas W. Healy

Particles present in mineral processing systems that are termed ultrafine are those that are small enough to be unaffected by gravity or the flow conditions imposed on the pulp. As such, their interaction with one another and with other larger particles are controlled by specific attractive and repulsive colloidal or surface interactions. Electrostatic repulsion between ultrafines is dominated by surface potential, double layer thickness and specific adsorption potential effects - controlled by pH, salt and complexing ion concentrations. Attraction due to van der Waals interactions must be assessed in terms of bulk and surface coating effects and of particle size and shape. The net effect of attraction and repulsion must finally be related to the average kinetic energy of particles in the real system.

Jan 1, 1979

By A. C. Coetzee

Blinkpan Koolmyne is as ten voile gemeganiseerde steenkoolvoorsiener aan die 1 000 MW Evkom-kragsentrale in die Oos-Transvaal, onderhewig aan groat seisoenale produksieskommelinge. Die aanwending van 'n groat bogrondse oap opgaarhoop vir die uitstryking van hierdie wisselende aanvraag word beskryf. Twee produksierasionaliseringsfases wat hierop volg het besondere bemoedigende resultate gel ewer, beide in toerusting- en mannekrag-produktiwiteit. Die aanwending van 'n rekenaarprogram vir die simulering van ondergrondse afbouaktiwiteite met die oog op toerustingkeuse, word aangegee. Voorlopige resultate wat in die praktyk behaal is dui op 'n hoë mate van betroubaarheid vir die program, terwyl die gebruik van die nuutste tipe hoë -kapasiteit laaimasjiene, koolsnyers en wisselkarre, groat potensiaal inhou.

By K. R. Gardner, P. B. Altringer, R. H. Lien

The Bureau of Mines, U. S. Department of the Interior, is investigating biological and chemical reduction of selenate and selenite from waste waters. A mixed bacterial culture, isolated from agricultural waters, removed selenium from four oxidized cyanide solutions from precious metals operations containing 0.6 to 30 ppm Se and 13 ppm CN. Up to 85% selenium removal was attained using bacteria under controlled batch conditions in a 3-L stirred tank reactor and in small-scale continuous tests conducted in a rotating biological contactor (RBC). Fe(OH), reduction of the selenium reduced the effluent concentration to 0.02 ppm Se; however, the reagent costs were prohibitive. A final processing scheme may involve a combination of biological and chemical treatments.

Jan 1, 1991

By Michael Goldin, Jonathan Ladner, Thomas Peacock, Nathaniel Johnson, Patrick Haley, Kris van Nijen, Andrew Rzeznik, Pierre Lermusiaux, Matthew Alford, Carlos Munoz-Royo

Surface processing vessels for deep-sea nodule mining operations will produce dewatering plumes that will be released at some depth into the ocean water column. We are studying all aspects of this part of the nodule mining process. First, we have developed analytical and numerical models to determine the effects of highly non-uniform, realistic stratifications on forced, compressible plumes with finite initial size. The classical plume model is developed to take into account the effects of compressibility and thermal conduction through the dewatering pipe. Our results show how small-scale features of a realistic stratification can have a large effect on a plume, and provide a basis for determining at what depth dewatering plumes can be released. These results form the basis for our PLUMEX field experiments, in which we will study the dynamics of dewatering plumes over the course of one week of field tests from the vessel R/V Sally Ride. The field experiments will use a Remotely Operated Vehicle (ROV) and a Phased-Array Doppler Sonar (PADS) system to study the characteristics of the dewatering plumes. The subsequent transport of the material in the dewatering plume will be monitored via shipboard surveys and, potentially, Autonomous Underwater Vehicle (AUV) operations, and these studies will be integrated with near real-time, data assimilating numerical model predictions. The ultimate goal of this project is to develop a field validated, recommend strategy for the release and monitoring of dewatering plumes, to help inform the development of ISA regulations and the planning of industrial operations.

Jan 1, 2017

By M Fahey, A B. Fourie

Over the past ten years, the mining industry has witnessed the introduction of a new and innovative mine filling technique known as paste fill, which consists of placing full stream tailings with small amounts of binder and water into underground stopes. Paste fill has benefits over traditional backfill methods, such as higher solids contents than hydraulic fill and easier transportation than rock fill. From a geotechnical perspective, the behaviour of very fine material in a fully saturated state can be complex, particularly when binder is added. Previously, there has been no rigorous solution to understanding the paste fill deposition process, resulting in uncertainty regarding critical aspects such as barricade load calculations. This uncertainty has the obvious consequences of potential barricade failures (including at least 12 over the past four years), and for many operations attempts to deal with this uncertainty has led to excessively conservative filling schedules, restricting production. This paper presents an application of Minefill-2D, the first rigorous model capable of representing the paste fill deposition process. The model couples the processes of material accretion, consolidation and cement hydration to calculate the distribution of stress around a stope (including the total stress applied to barricade structures) during filling. Minefill-2D is a finite element numerical program, which has been verified using laboratory element tests, centrifuge tests and in situ measurements (Helinski, 2008). The authors present a sensitivity analysis, carried out using the model, to demonstrate some of the critical and less critical aspects relating to paste backfill deposition. The results of this sensitivity analysis are used to devise a fill management strategy that can be utilised to minimise the risk of barricade failures and maximise fill rates where appropriate.

Jan 1, 2008

A computerised influence function approach to subsidence and horizontal displacement prediction is described, with particular emphasis being placed on the applicability of the method to irregular- shaped mine workings. Based on previous work [1], this approach has been put for- ward for inclined seam situations. Examples of graphical output presenting surface subsidence contours, horizontal displacement vectors and principal strain vectors are given and their significance discussed in relation to current problems.

Jan 1, 1988

By L. Piga, G. Belardi, V. Alesse, N. Shehu, J. Freund

The physico-chemical interactions among minerals such as olivine, chromite and serpentine; the most commonly present ions in solution such as Ca and Mg; and flotation reagents such as EDTA and oleic acid were investigated. The study was conducted via release tests, electrophoretic measurements and microflotation of selected minerals coming from the Kukes deposit in Albania. The results were confirmed in beneficiation tests on two ores, one from the Kukes (Kalimash) deposit and the other from the Rizo deposit in Greece. It was demonstrated that, when Na-oleate is used as collector, chromite, olivine and serpentine can be separated at pH 2.5 and/or pH 5.5 when employing ethylenediamine tetraacetate (EDTA) on previously deslimed material. This approach ensures flotation concentrates with a Cr203 content better than 50% with a recovery of more than 75%.

Jan 1, 1998

By R. H. Grau, S. B. Robertson, R. B. Krog, T. P. Mucho

Stone mines represent the highest percentage of operating underground nonmetal mines in the United States. With the introduction of stricter Diesel Particular Matter (DPM) regulations, large-opening underground room-and-pillar stone mine operators are faced with implementing one or more alternative methods to reduce concentration levels including: install and maintain an effective ventilation system; install lower DPM emission diesel engines; the adding of DPM filters. The National Institute for Occupational Safety and Health (NIOSH) is actively researching various aspects of fan and stopping designs in an effort to improve the ventilation of these mines. NIOSH has identified and further developed three alternative ventilation methods for use in large-opening underground mines: split-mine, perimeter, and unit-ventilation. This paper describes the implementation of the three methods with respect to their use in mines of various levels of development.

By S. Veeramasuneni, C. D. Dunbar

The rate of hydration influences many important physical properties of gypsum. Previous research examined the rate of gypsum hydration and related this to compressive strength and microstructure development using BET specific surface area analysis. The analysis of gypsum porosity in combination with BET surface area and rate of hydration remains to be done. In the present study, mesoporosity is analyzed using the numerical method of Barrett, Joyner and Halenda (BJH) to gain a greater understanding of gypsum hydration and microstructure development. The rate of hydration has a significant effect on mesoporosity of the gypsum matrix. The results reveal the effect of mesoporosity and hydration rate on some macro physical properties of gypsum.

Jan 1, 2000

By Henry Leidheiser, Melvin C. Jr. Hobson

The rate of formation of the intermetallic compound, indium antimonide, at the interface between iudium and antimony at 100°C is greatly increased when a composite electrode of indium electrode -posited on antimony is made the cathode in an electrolytic cell. The amount of indium antimonide formed during electrolytic treatment at constant potential appeared to he proportional to the square root of time, but the scatter of the data, particularly at long times, makes it impossible to state this conclzlsi1:ely. The rate constant for the electrochemical synthesis was estimated to he 1.5 x 10-12 sq cm per sec. A similar- set of experiments was conducted in the absence of an applied potential but under otherwise similar conditions. The rate constant lor the thermal synthesis was less than 2 x 10-14 sq cm per, sec, at least two orders of magnitude less than obtained during electrolytic treatment. In a series of electrochemical studies it was observed that intermetallic compounds formed on the surface of polarized electrodes.1'2 The possibility of using this technique for the electrochemical preparation of intermetallic compounds was investigated and subsequently applied to the synthesis of the semiconducting III-V compounds. Gallium antimonide, indium arsenide. indium antimonide, and indium bismuthide were successfully formed by electrodepositing the Group III element from a boiling acid solution onto an electrode made of the Group V element. The following kinetic studies were undertaken on indium antimonide to obtain quantitative information on the rate of formation of this representative III-V compound under a potential gradient. EXPERIMENTAL The electrolytic cell for these experiments was a modified, three-neck, round-bottom, 500-ml distillation flask. Sealed into the side of the flask was a Luggin probe which monitored the surface of the working electrode and extended out of the flask to a small reservoir containing a saturated calomel electrode. The counter electrode was platinum. The three electrodes were connected to a Wenking po-tentiostat which maintained a preselected constant potential near the surface of the working electrode with reference to a saturated calomel electrode. All potentials noted in this paper are with reference to a saturated calomel electrode at 45° ± 5°C. The potential and the current were both monitored using Sargent Model MR recorders. The antimony electrodes were cast in graphite molds to form spheres about 15 mm in diameter with a shank 6 mm in diameter and 10 mm long. A heavy copper wire (12B & S gage) was soldered to this shank. Collodion was applied for protection to the shank and the connecting part of the copper lead. A snug-fitting O-ring was slipped over the shank and the electrode was then fitted into a teflon holder such that only the spherical portion was exposed. The electrode surfaces were cleaned and chemically polished prior to assembly and introduction into the electrolyte by etching in a modified CP-4 solution (50 parts glacial acetic acid, 10 parts concentrated nitric acid, 2 parts 48 pct hydrofluoric acid). The electrolyte was 10-2 M In+3 in 1 MH2So4 and its temperature was held constant by refluxing. The reflux condenser was open to the atmosphere and no temperature correction was made for changes in barometric pressure. The indium concentration in the electrolyte was checked from time to time by the analytical method outlined below for the determination of the amount of indium antimonide formed electrochemically. A schematic of the recorded potential is shown in Fig. 1. At point A the antimony electrode was introduced into the cell and the open-circuit potential recorded. At point B the potentiostat, preset at the desired potential, was switched on. It was switched off at point C and the potential fell to the open-circuit value of the electrodeposited indium. The

Jan 1, 1965

By Scott Gustfason, Richard N. Snyder

What is a safe stand-off distance? Recent mishaps using conventional blasting equipment have seen flyrock as distant as 3,750 feet from the blast area, or close to three-quarters of a mile, therefore, whether below ground, under water, in surface quarries or at a structural demolition site, data signals riding a radio wave promise a new horizon for the users of both electric and non electric blasting circuits.

Jan 1, 1987