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The following brief paper is intended, to apply to the concentration of the silver-lead ores at Broken Hill, New South Wales, generally, but more particularly to the process as applied to the ores in the Block 10 mine. The attached plans are similar inmany respects to those prepared, recently for the Block 10 company.Most of the information here given is already well known to those members who are conversant with the concentration practices of this field, but it is the writer's object to give just a few of those figures which he found difficult to obtain when first engaging in practical work. At that time no text-books were at hand from which it was possible to get sufficient details for practical working purposes.It is first supposed that the mine has been thoroughly explored and has been found to contain a lbde sufficient in size ·and quality to warrant the erection of a concentrating plant. The points then to determine are:-(1.) The quantity and cost of water available for steam-making and ore-dressing purposes.(2.) The most convenient site for the mill.

Jan 1, 1904

By T. A. Sullivan

The processing of sweated aluminum electronic scrap was investigated to develop methods for recovering the aluminum and concentrating the other metals, including copper, lead, gold, and silver, into a product that can be separated by known methods. Two molten-salt electrorefining processes were developed and tested. The first process utilized a three-layer refining cell with a BaCI2-NaF-AIF3 electrolyte, which operated at 750° to 850° C. The second process used an all-chloride electrolyte of NaCI-KCI-AICI3 at 750° to 800° C, with separate anode and cathode compartments. High-quality aluminum was recovered that averaged 99.8-percent pure in the three-layer cell and 99.6-percent pure in the compartment cell. Over 94 percent of the aluminum was recovered with cathode current efficiencies of approximately 90 percent in both methods. The copper, lead, tin, silver, gold, and other metals were concentrated threefold in an anode product. Separation of lead and part of the tin by liquation from this product seemed feasible. The anode product was smelted to prepare a 96-percent copper bullion that contained 690 ounces of silver and 65 ounces of gold per ton, with 98 percent recovery of these values.

Jan 1, 1972

By F. F. Skiba, P. J. Root

A mathematical model has been used to investigate crossflow effects in a stratified reservoir during an idealized displacement process. A process in which one incompressible fluid displaces completely another incompressible fluid of the same density and viscosity was considered. The reservoir was assumed to be composed of homogeneous layers which are discrete but interconnected. Approximate five-spot flow geometry was simulated by arranging two pie-shaped cylindrical (two-dimensional) wedges in series. Some of the common production methods rely, for their effectiveness, on the fact that the formation consists of isolated strata. This is particularly true of selective plugging and single-zone production-injection methods. The effectiveness of these techniques for several cases in which adjacent strata are in communication has been evaluated. The usual production-injection schemes for fluid injection processes involve using the same completion interval in both the production and the injection wells. The efficiency of this, as well as alternative productioz-injection procedures has been examined for some cases involving communicating strata. INTRODUCTION The performance of many fluid injection projects is marred by early breakthrough and by production of a high percentage of the displacing phase after breakthrough. This channeling effect, if it occurs in reservoirs which have large permeability variations, is often explained on the basis of a model composed of discrete, isolated strata. Corrective or preventive measures based on this same model are also common. The behavior of stratified models has been the subject of considerable study. An excellent review of the early literature was given by Seba.1 Studies of the depletion performance have since been made for continuous, unrestricted communication between strata2-4 and for production from one permeable bed in continuous but restricted communication with an adjacent permeable bed.5,6 Model studies of displacement processes in stratified systems with crossflow also have been reprted.7-12 Finally, methods which account for crossflow have been developed for computing displacement behavior in stratified systems.13,14 Most methods for controlling or preventing channeling involve some change in the interval open to production and/or injection. Although many variations of the selective completion problem have been studied in regard to the depletion of a reservoir, little attention has been given to the behavior of a displacement process under similar conditions. Sebal used a resistance network model to study the performance of a process in which one incompressible fluid displaces an identical fluid from a linear, stratified reservoir. He investigated the possibility of improving the vertical coverage by limiting the completion interval of the production well. This investigation deals with techniques in which selective completion of the production and/or the injection wells is used in an attempt to control channeling. At one extreme, selective plugging and single-zone isolation (assuming perfect execution) should be successful if the reservoir is actually made up of independent strata. At the other extreme, they can hardly be expected to be successful if the channeling is caused by a mechanism in which stratification effects are negligible even though there are extreme variations in the formation permeability and/or the injectivity profile of the wells is not uniform. By contrast, it is difficult to anticipate the effect that the amount of communication between the beds of a stratified system will have on the efficiency of selective completion techniques. The objective of this study is the quantitative determination of the effect of communication on the behavior of some particular stratified systems which will at least lead to qualitative conclusions.

Jan 1, 1966

Paper presented at the UK minerals industry conference and published in: Minerals extraction towards the millennium. UK minerals industry conference, 3-5 April 1995, University of Leeds. London: Institution of Mining and Metallurgy, 1995. The various types of risks that arise in minerals industry projects are usually financial, technical, or environmental, and the key to valid risk analysis is complete integration of all risks, both within and between categories. Geographical information systems (GIS) and geostatistical simulation methods can provide a means of integrating data and conducting realistic risk analyses. Risk can be quantified but there are limitations to numerical approaches to risk assessment. Realistic quantification requires adequate models of the processes that give rise to risk. Risk perception must also be taken into account when conducting risk assessment and reporting the results, especially in public forums. The modelling and visualisation capabilities of a combined GIS/simulation system can provide the means of dealing with perception in risk analysis

Jun 19, 1905

Characterization of ore and waste-rock material using automated quantitative micro-mineralogical techniques (e.g., QEMSCAN® and MLA) has the potential to complement traditional acid-base accounting and humidity cell techniques when predicting acid generation and metal release. These characterization techniques, which most commonly are used for metallurgical, mineral-processing, and geometallurgical applications, can be broadly applied throughout the mine-life cycle to include numerous environmental applications. Critical insights into mineral liberation, mineral associations, particle size, particle texture, and mineralogical residence phase(s) of environmentally important elements can be used to anticipate potential environmental challenges. Resources spent on initial characterization result in lower uncertainties of potential environmental impacts and possible cost savings associated with remediation and closure. Examples illustrate mineralogical and textural characterization of fluvial tailings material from the upper Arkansas River in Colorado.

Feb 27, 2013

By J. N. Van der Merwe

The principal goal of the research described in the paper was to determine, by measurement of pillar scaling on pillars that have not failed, whether the pillar life prediction method developed by van der Merwe (2003) was valid as it stood or whether adjustments were necessary to the rates indirectly derived from observation of failed pillars. To this end, measurements were taken on over 350 pillars at 13sites on 6 mines. The project was done as a collaborative effort between the University of Pretoria, the Nancy School of Mines and CSIR Miningtek. During the course of the investigation, it was found that the majority of pillars display maximum scaling at mid height, that there was no clear preferential direction of pillar scaling, and that pillar corners do not scale significantly more than the mid pillar areas. The most important conclusion was that the scaling rates found by measurement agreed with the inferred rates found in the previous work. The previously developed procedure for the prediction of pillar life spans consequently requires no adjustment, although the error span is in the region of 20%. It is recommended to do further research into the effect of sealing of panels and, possible chemical changes taking place in the pillars as they age on the scaling rate.

Jan 1, 2004

By Gilberto Yanarico Apaza

"El presente texto señala las pautas necesarias para realizar una evaluación técnica integral de la influencia del collar de bolas para las operaciones de molienda, afectando al desgaste de los revestimientos de los molinos convencionales. Para la determinación del collar de bolas es necesario realizar los análisis granulométricos con la finalidad de obtener el F80 y el P80 de las muestras obtenidas en la alimentación y producto de los molinos, definir el índice de trabajo (Wi) y consumo de energía. Asimismo, se debe considerar el porcentaje de la velocidad crítica, las dimensiones de los molinos, la densidad de los medios de molienda (bolas), el porcentaje de la carga de bolas, las características geométricas de las bolas para molienda y el diámetro real de bolas, que influye de forma inversamente proporcional en la tasa específica del consumo observada."

Jul 1, 2015

By H. S. Kennedy

THE HELIUM ACT (50 Stat. 885; 50 U. S. C. 161,163-166), as amended, places the responsibility for conserving, producing, and selling helium upon the Secretary of the Interior, acting through the Bureau of Mines-the only producer of helium in quantity in the world. It operates 4 plants-I each at Amarillo and Exell, Tex.; Otis, Kans.; and Navajo (Shiprock), N. Mex. The demand for helium has increased steadily since the decline immediately after World War II and is expected to exceed the capacity of the present plants in the near future. The Congress has appropriated $6,000,000 far constructing a new plant. In addition to providing additional capacity to meet increased demands for helium, the new plant will enable the Bureau of Mines to better conserve the helium in, the Government-owned reserves at Amarillo and Navajo.

Jan 1, 1958

By Taylor R. G

This paper reports a biogeochemical study of the Siberia lode of the Herberton tin field. Soil near the orebody contained high levels of Fe, Cu, Pb, Sn, As, Mld Mn. Polycarpaea spirostylis and Indigofera dominii were associated with these high levels but several other species apparently could not tolerate them. The potential of these species as indicator plants is discussed.

Jan 1, 1975

By Samuel Canchaya

Los paquetes medianos y grandes de software a minería contienen en sus módulos de estimación de reservas alguna forma de análisis variográfico geoestadístico. En esa perspectiva, el presente trabajo señala la optimización de métodos tradicionales utilizados en dicha estimación a través de los conceptos y parámetros de la caracterización variográfica y estadística psra así minimizar las limitaciones de los métodos tradicionales.

May 25, 1998

By K. J. Fair, H. W. Smith, D. R. Francis, J. M. Toguri

"Bench-scale batch milling and screening tests were carried out on secondary aluminum dross 10 produce an aluminum concentrate. To complement these tests, an analysis of a commercial plant was also performed by sampling dross at various stages in the plant's milling and screening circuit. These studies have indicated that benefits of increased capacity, grade and recovery of aluminum metal can be realized by addition of screens before the ball mill, longer grinding period and by grinding the smaller size fractions more efficiently.To test the predictions, a plant test was performed on the milling of100tons of secondary dross. The recycling of the large size fraction (+1/8 in.) of aluminum dross through the impact mill rather than through the rate limiting ball mill resulted in a comparable aluminum grade. The ball milling of the _1/ 8 in. + 10 mesh size gave a dross grade of71% AI. A lower feed rate to the ball mill resulted in a higher final grade. With minor modifications, secondary dross can be processed in 22% of the time it takes with the present circuit without a sacrifice in grade.IntroductionSecondary aluminum dross is a mixture of metallic aluminum, aluminum oxides and salts (alkali halides). Any comminution process deforms or slowly grind s the malleable metal phase and reduces the size of the friable, brittle, oxide-salt phase relatively fasterr(1).The milling of aluminum dross is performed to upgrade the metallic aluminum fraction. Figure I shows a flowsheet for the milling of secondary dross as presently practised at Metals and Alloys Co. Ltd., Toronto, Ontario. At point A, large acceptable grade material is hand picked for refurnacing, the unacceptable off-grade material is sent to the sweat furnace and the remaining, + 2 in. fraction is recycled through the 3.9 ft by 4.1 ft impact mill. For simplification, three ball mills are shown. However, in reality there is only one, a 5 ft by 10 ft ball mill used in a semi-batch mode. The 2 in. + 3/8in. and 3/8 in. + 10 mesh products are remilled in the ball mill. The -10 mesh material is discarded as waste."

Jan 1, 1987

By E. R. Maize

[In report of Investigations 3452,5/ baling with roof movement in the Crucible mine, reference was made do to the fact tart timber decay was being studied at the time of writing. This roper, written after completion of that study, describes s the work and summarizes the data obtained. When the study of roof movement as begun at Crucible two ideas were advanced on decay Of timber by some of the officials: (1) That timber decay vas unusually rapid in the Crucible mine, and (2) that timber coated with rock dust decayed more rapidly than those teat were not so coated. There yore no records by which these ideas could be tested, and it appeared wise to make a limited; investigation particularly of the effect of rock dusting on decay, as rock dusting is an important means of preventing coal-dust explosions.]

Jan 1, 1940

By William M. Camp

An extensive design phase testing program in which 10 piles and 2 drilled shafts were instrumented and statically load tested to failure, was undertaken to establish relevant foundation design parameters for two bridges in Charleston, South Carolina, USA. The bearing strata at both test sites was a calcareous, overconsolidated, firm to very stiff, slightly sandy, clayey silt (locally known as Cooper Marl). Confirmation dynamic and static loading tests on production piles indicated only 50 to 60% of anticipated pile capacities; including consideration of time effects. Supplemental subsurface explorations did not reveal any significant variations in marl properties. Ultimately, 22 static and 75 dynamic tests were performed on production piles for a 2 mile section of the project. Pore water pressures in the marl were also monitored during and after pile driving. A study of unit skin friction in the marl as a function of time revealed two distinct trends: piles driven in areas with a sand overlaying the marl gained more capacity significantly faster than those driven through a clay or silt. Although the insitu marl properties are apparently similar across the site, the material immediately above the marl evidently has a large effect on pile capacity. This effect of overburden on pile capacity was verified by testing piles over a period of two years.

Jan 1, 1993

By Irving Hartmann

[The explosability of coal dusts has been the subject of many investigations studies have been conducted in laboratories, in galleries and in coal faire; of several countries to obtain information on the causes, development, and prevention of mine explosions. Early laboratory experiments on it American colas dealt with pressures developed in test bomb by explosions of dust clouds and with, the effects of gas in the dust atmosphere.5/ Later, the emphasis shafted to evaluation of the relative fleet flammability and the ignition temperatures of coal dusts.6/ Much worthwhile effort was devoted to the development of Laboratory apparatus and test procedures that gave good correlation with large-scale explosion tests in the Experimental cost mine. In recent years a number of special problems were studied, mostly with bituminous Pittsburgh coal dust]

Jan 1, 1954

By P. R. Brenchley

Main ore pass systems should last the life of a mine, and too often expensive and hazardous remedial measures are required to repair a damaged ore pass in an attempt to extend its life. In order to maximize the life expectancy of all ore passes at Moab Khotsong, ?wearing blocks? and ?softer support? systems, combined with basic rock engineering principles, have been implemented. Failure of an ore pass can have severe financial implications, both indirectly because the ore pass cannot deliver the broken rock either from level to level or directly in the shaft ore pass system to the required level for tramming to take place, and directly due to the cost of the repair work that is required. Several factors need to betaken into consideration so that production interruptions are eliminated or minimized. Investigations of damaged ore passes at Moab Khotsong and surrounding mines revealed some interesting mechanisms of damage, and some innovative methods of reducing or eliminating the damage have been implemented at Moab Khotsong. The system design was based on 30 years, experience in main shaft rock passes. The design was to counteract scaling, hang-ups and dust problems associated with main rock passes, and the objective was to increase the life of rockpasses. These problems, including the initial design aspects to try and eliminate the repair measures, are discussed in detail.

Jan 1, 2006

By B. S. Terry, C. L. Harris

Reduction kinetics from slags containing CuO(0.5), ZnO, PbO, NiO and SnO into a Cu-based metal phase were subjected to computer simulation using a previously developed model for the kinetics of metal-slag-gas reactions that assumes mass-transfer control in all phases. The effects were examined of changing bulk Fe oxide activity, gas reducing potential, temperature, Fe content of the Cu phase and metal/slag ratio. The results permit practical conclusions to be drawn about industrial slag-cleaning practice, but the model is still limited in terms of thermodynamic inputs and the idealisation of reaction conditions

Aug 1, 1995

By A. G. Doll

"Multi-stage crushing plants, including high pressure grinding roll (HPGR) circuits, require more materials handling equipment than SAG and ball mill circuits. A temptation exists to neglect the energy consumption of materials handling when doing desktop comparisons of HPGR versus SAG milling circuits because estimation of materials handling power requirements can demand significant general arrangement drafting that is not available when performing preliminary scoping or ""desktop"" studies.The largest component of materials handling power is consumed by conveyors when lifting material between stages of crushing, meaning that a simple potential energy model can be used to evaluate conveying specific power consumption. This potential energy consumption for conveying can then be factored to provide overall materials handling specific energy consumption suitable for desktop studies of HPGR and other multi-stage crushing circuits. The technique also permits different crushing circuit flowsheets to be evaluated, at a preliminary level, by simply counting the number of times a conveyor must ""lift"" ore from ground level up to a bin or other equipment mounted up high.INTRODUCTIONTrade-off studies of multi-stage crushing plants involving high pressure grinding rolls (HPGRs) versus semi-autogenous grinding (SAG) mill circuits typically focus on the operating cost savings of crushing plants versus the capital cost savings of SAG mill plants. Very high-level (or desktop) studies of this type do not include a great deal of engineering work, meaning that the details (and costs) of ancillary systems are often not captured when doing the comparisons. The more complicated nature of the multistage crushing plants means there are more ancillary systems than a SAG mill plant, risking a skewed analysis of the operating costs, benefiting the HPGR option.One of the ancillary systems that may be overlooked is the more complicated conveying systems inherent in multi-stage crushing plants. Due to the mass of material being handled in large mining operations, these conveyors become a significant portion of the operating costs. A simple way to estimate the specific energy consumption of conveying systems without requiring engineering drawings and a site layout would allow high-level studies to capture this operating cost."

Jan 1, 2015

By Karsten Beckhaus

"Abstract Tremie concrete for special geotechnical works needs special properties, especially during the casting process. Today’s execution standards for bored piles and diaphragm walls, EN 1536 and EN 1538, as well as the draft version of concrete standard EN 206, all comprise regulations for deep foundation concrete which have not been changed for decades. Considering the recent development in concrete technology at the same time and its actual state-of-the-art, it is essential to develop new normative specifications and specification requirements.GeneralTo allow the required integrity and quality after placing and hardening, concrete for structural elements like bored piles or diaphragm walls, used as foundations of high-rise buildings or as retaining structures for large and deep building pits, must have adequate workability and stability.In addition to requirements on mechanical properties and on durability, both of which have increased within the last decades, concrete must be suitable for being cast in deep or extremely deep excavations, see figure 1. Today’s specialist foundation engineering machinery makes it possible to drill or cut down to in excess of100 m depth. Concrete technology has developed and allows the use of high performance concrete for deep foundations. But is this capability represented by actual regulations?It has become very common for the industry to supply or use concrete with low water cement ratios, nevertheless highly flowable and set-retarded for several hours if needed. Very low water cement ratios allow design strength of 60 MPa or higher (Larisch, 2011), and a very low porosity which is required for a long service life in aggressive conditions, e.g. by chlorides.To achieve best performance, it is obvious that the concrete must completely fill the excavation and fully embed the reinforcement. As vibration of deep foundation concrete is (usually) not allowed and was anyway inefficient, deep foundation concrete must be designed to self-compact under hydrostatic pressure. Generally, it must be considered that after placement the concrete’s quality cannot be influenced anymore. Therefore, both the pouring procedure and the concrete quality must be adequate."

Jan 1, 2014

"Gravity concentration remains the main separation method for fine iron ore and is used extensively for treating various minerals. Gravity concentration methods separate minerals of different specific gravity by their relative movement in response to gravity and one or more other forces, the latter often being the resistance to motion offered by a viscous fluid, such as water or air (Wills, 2006).Spirals concentrators are one of the gravity concentration equipment used for beneficiation of minerals. Spirals are typically used for processing of fine minerals (-1mm) size fraction. The main operating variables for a spiral concentrator are the feed rate, the solids concentration, the wash water addition and the position of the cutters or splitters used to separate the tailings, middling and concentrate streams (Sadeghi, Bazin & Renaud, 2014).The aim of this study is to investigate the effect of feed rate, solids concentration and wash water on grade and recovery on iron ore material. The Multotec SC20HC/7 WW spiral was used for the experimental test work. The spiral was tested at varying solids concentration and feed rate. The wash water rate was also varied to establish the best washing rate. The splitter positions were kept constant. Optimization of these variables is expected to provide optimum conditions for a good compromise between grade and recovery.INTRODUCTIONSpiral concentrators are simple low energy consuming devices that separate minerals mainly on the basis of density. Spirals are widely used in mineral processing as a method for preconcentration and have proven to be metallurgically efficient and cost effective.Spirals have a wide application, they are used in iron ore processing, coal, gold, chromites, mineral sands, glass sands, and in soil cleaning.Separation on a spiral is achieved through a combination of forces that act on particles as they move down the trough of the spiral. The main forces known to act on the particle on a spiral are the gravitational forces, centrifugal force, hydrodynamic drag, and lift and friction forces (Kapur & Meloy, 1998). Apart from the forces acting on a spiral, the properties of the slurry flowing on a spiral including, solids concentration, feed rate and wash water also plays an important role in the separation on the spiral.The relationship between separation efficiency and feed rate was shown to be linear, with a decrease in efficiency at higher flow rates. Previous work on flow profile by Holland - Batt (1990) indicated that any increase in the feed rate to a spiral results in a greater part of the additional flow volume reporting to the outside of the trough. The flow on the outside of the trough becomes energized and consequence to that the heavy particles find it hard to settle and escape this region to the inner region. This effect has a high impact on recovery of heavy minerals, since any increase in volumetric flow on the spiral is not made available for recovery in the inner region of the spiral."

Jan 1, 2015

FOR rapidly marking in geological and topographical features on parish plans, the author has used the Veeder cyclometer with very satisfactory results. A simple Veeder cyclometer, usually retailed at cycle depots at 4s., is fixed to the axle of the front wheel of an ordinary bicycle. The cyclometer is desigued to read in miles and tenths of miles, which are recorded through gearing actuated by a striker on a spoke of the bicycle wheel engaging one of the vanes of the cyclometer once every revolution.By using 80 strikers the reading would be in chains and tenths of chains; therefore the use of 8 strikers gives the reading in chains, utilizing all the figures. The cyclometer is designed to be placed on the right-hand side of the bicycle, and takes up a minimum of space, being only about the size of the top joint of the thumb. With some makes of cycles there is insufficient clearance, so the cyclometer must then be placed on the left side, and the 8 strikers made to engage the top vanes, as shown in the sketch (Fig. 1).Very accurate readings can be obtained by this instrument. The author has found by numerous tests that the maximum error...

Jan 1, 1916