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By W. J. Birch, R. Farnfield, L. Bermingham

Whilst a significant body of research has been carried into air overpressure levels that arise as a result of the use of explosives, few published studies have actually tried to relate the movement of a quarry face to the resulting air overpressure produced. The aim of this preliminary investigation was to monitor a number of quarry blasts at two different limestone quarries. The first using multiple separately initiated deck charges in a multi borehole blast, the second using single column charges in a multi borehole blast.

Jan 1, 2008

By B. Erdem

This article introduces a computer model, which emphasizes panel design for draglines deployed in direct side-casting mode. The study covers flat and inclined coal-seam conditions with the dragline operating along the strike-line. Two casting methods are embedded in the model: material is placed in the open set adjacent to the one on which the dragline is located (the DNS method) and material is placed in the open set adjacent to the one the dragline excavates (the DND method). While in the first method the unproductive walking time is reduced as the set is enlarged, in the second method the cycle time is lessened as the dragline swings along an acute angle. The side-casting model is shaped so as to provide several panel configurations instead of a single one to conform to the characteristics for an opencast mine. This is achieved by assigning the pit width an interval of values ranging from a minimum to a maximum. The model includes solutions to other critical design parameters such as: set length, swing angles at key cut and main cut positions, and required dragline reach at key cut and main cut positions. The model outcomes reveal the following: the stripping operation is largely affected when the coal-seam is inclined. The downhill spoiling mode should be applied wherever possible. The DNS pattern allows wider pit width intervals as well as longer sets and longer reaches.

Jan 1, 2004

Experimentally determined and theoretically explained phenomenon of zonal disintegration of rock around the development working brings about the radical changes in existing ideas about the mechanism of interaction rock massive with engineering constructions.The essence of the phenomenon consists in the fact, that forming of non-elastic deformations zone goes on by way of more intensive deformation and destruction of rock simultaneously in several zones, covering partially or fully output circuit and divided by zones of destructed rock. Under the influence of change of massive strained-deformational condition of depositional rock an accidental deviation of zones of supplementary expansion and compression of rock from the previous positions take place. One can observe multiplicational change of the outline, size and form of all disintegration zones in the time within the area of the working influence at massive. This phenomenon was named "fluctuation of zonal disintegration of sedimentary rock around development working".

Jan 1, 1991

By Rob Morrison, Andrew Scott

"Long before a modern mine commences operations it has already become a wealth of information. After start up, it can generate enormous quantities of data – especially with semi-automated data acquisition by instrumented mine equipment. Much of this data is of limited use for evaluation of (potential) performance unless it links in some way to the site business model.An underlying reason for this waste of data is that the different cultures, financial, technical, community, environmental, etc, not only have many areas of interest but also have very different conceptual models by which they evaluate performance.It is too ambitious to attempt to bring all of these cultures together – in a single step. However, the success of the Mine to Mill ™ project has demonstrated that substantial operational value can be added by using a more integrated approach to comminution. The next logical step is to integrate measured data and then to track performance from ore body model to saleable product and waste disposal.The path from resource to product also represents a path from very sparse, highly variable data to much more detailed measurement and more representative sampling. However, in both cases the data collected is usually strongly focused on the technical requirements – not on the business model.This paper emphasises the difference between data and information. There is considerable potential for confusion between the two as both data and information are often expressed as numbers. For the purpose of this paper, data and information are distinguished by their uses.A data point (or datum) is a measurement. By way of contrast, information provides a basis for decision making."

Jan 1, 2003

By Christoph Mueller

Mining operations are characterized by cost pressure and cycling product prices. A high potential for enhancing efficiency is the integration of all single steps of the mining working chain into a production process structure to make advantage of an optimized flow of material and information through the ?moving ore factory?. As modern mining machinery today is controlled electronically and even already operated autonomously, a smooth and cost efficient flow of data in the mining process will be crucial for cost efficient future mine operations. Therefor, the International Rock Excavation Data Exchange Standard (IREDES) was launched by major players in the industry. The task of this initiative is to define a ?common electronic language? for easy and standardized data exchange between mining machines and central computer systems. As in other industries, this standard is expected to have significant impact on the use of automated equipment. It shall provide easy ways of using multi vendor machine installations in data controlled mining processes. At the same time it reduces cost for individual development of interfaces for all parties involved. Standardized data exchange is also a crucial precondition to integrate the mining process into enterprise level modeling, cost analysis and decision finding systems. The standard?s technical architecture is open and flexible for future applications. It uses modern XML technology enabling easy data exchange with commercial databases as well as open on line networking. The IREDES work is carried out by the initiative members working jointly together in the technical work groups. Prototyping implementations of the Drill rigs profile are currently going on. Further profiles under development cover LHD?s/Loaders/Trucks and Explosives Chargers. The first official release covering the Drill Rigs profile is planned for the end of 2002.

May 1, 2002

By J. C. Griffiths

There are two kinds of problems concerning the elements of a population : the first is to estimate the proportion of some specific kind of element in the population, e.g. the amount of gold in a block of ground (equals population) or the proportion of mercury in a sample; the second is to estimate the length, breadth, volume, etc., of a specific kind of element, e.g. the grain size of quartz grains in a beach sand or the size, shape and arrangement of lenses of ore in an ore deposit. Given a specific objective, a bounded population, identified elements and the element characteristics of interest, it is then necessary to select a sample of the elements from the population and the problem of sampling requires a decision on how to select the sample. It is also necessary to establish, either by heuristic analysis or empirically, based on long experience, the model frequency distribution of the desired element characteristics: in general, constant-probability models are used as models, the binomial or Poisson for count data and the normal distribution for measurements (or their transformed equivalents). The objective of sampling then becomes to obtain an appropriate statistical estimate of the desired population parameter: for example, the estimators may be the mean (X) and variance (a2): these should be unbiased sufficient estimators of their corresponding parameters (u, a2, respectively). Statistical tests are performed in order to determine that the estimators are of the appropriate kind: all statistical tests are designed to test against bias of a specific kind, although they are stated as tests against randomness. Given a random sample of some population, the estimators are usually stable and adequate to solve the sampling problem. Random samples are simple to define but exceedingly difficult to achieve in practice: in selecting a sample, if every element in the population has an equal chance of occurring, then the sample is a random sample. Interaction between the arrangement of elements in a population, i.e. its structure, and the sample selection process frequently introduces bias—that is, some elements have more chance than others of appearing in the sample and, hence, the sample is not random. An algorithm for dealing pragmatically with this aspect of the sampling problem offers one way of achieving random samples and, therefore, adequate estimators. Examples of the use of this algorithm on various kinds of geological populations, in both field and laboratory, illustrate the requirements for solving sampling problems and the achievement of appropriate estimators.

Dec 1, 1971

By D. R. Nagaraj, Napoleon Tercero, Raymond Farinato

Historically, as for most reagents used in flotation, the wide-spread use of dialkyl dithiophosphinates as collectors in practical applications has preceded a detailed scientific understanding of how they work. Dialkyl dithiophosphinates are a technologically and commercially important class of collectors used in the flotation processing of Cu-Au, complex polymetallic, and precious metal ores. Plant usage has demonstrated that dithiophosphinates exhibit higher selectivity and flotation rates for Cu sulfides, galena, and precious metal values in the presence of other gangue sulfides, than the traditionally used collectors such as dialkyl dithiophosphates and xanthates. They also have an attractive health, safety, and environmental (HSE) profile. Although dithiophosphinates received little attention in the past in the flotation research community, recently, there has been significant interest in this chemistry, and numerous studies have been conducted to understand the fundamental interactions of dithiophosphinates with several base metal sulfides and precious metals. A critical overview of fundamental studies, laboratory ore flotation, and plant practice of dithiophosphinates is given in this paper. The findings from these studies are rationalized and explained by drawing on concepts and insights from coordination chemistry. A comparison between the interactions with various minerals and metals of dithiophosphinate and dithiophosphate analogues brings out some of the subtleties that seemingly minor changes in collector chemistry can make. The critical overview and analysis given here is useful in identifying gaps in knowledge regarding this important class of compounds. This in turn can provide a basis for the design of studies to advance our understanding of dithiophosphinate flotation performance.

By Mark Sanders

This report compares a proposed 10/60 "piggyback" 02 generating self-rescue unit to the standard CO self-rescue unit with respect to work task interference. A simulated low seam coal mine was constructed and subjects performed locomotion, shoveling, cart pushing, and timbering tasks with the 10/60 or self-rescuer attached to their belts. Task completion time was longer on all tasks when wearing the 10/60 unit, although only locomotion was statistically significant. The 10/60 unit was bumped over 100% more often than the standard self-rescuer. Implications for design of the proposed 10/60 container are: 1) unit?s container must be extra durable to withstand the added abuse it is likely to receive by low coal miners; and 2) extra consideration must be given to preventing the device from slipping on the belt while working, especially in low coal.

Jan 1, 1980

By C. H. Lee, K. Adham, D. Lemieux, J. P. Mai, A. M. S. Hussein, S. Francey

Copper concentrates contain an increasing amount of arsenic, as the older sources of cleaner ores are depleted. At the same time, the market-determined price penalties on arsenic rich concentrates are rising due to limited arsenic treatment capacity at smelters and increasingly stringent environmental emissions limits, necessitating arsenic removal from the copper concentrates. Heating the concentrate to about 700°C can remove significant amounts of arsenic (as elemental and/or sulfide); however, it is important to achieve that removal economically and with due consideration to post-roasting arsenic (toxic waste) treatment. A comparison is made among different roasting options (kilns, multi-hearths and fluid beds) to qualify their potential application to arsenic roasting of copper concentrates. Both direct and indirect methods of heating as well as inert, air and oxygen atmosphere options are considered. Technology comparisons are made with respect to the roaster’s operation, its off-gas treatment and arsenic stabilization. INTRODUCTION In the last twenty years, the arsenic content in globally produced copper concentrates have risen steadily due to the depletion of cleaner ores and the increase in complex concentrate production. Smelter contracts typically limit arsenic to less than 0.5wt%, with a penalty paid per unit of additional arsenic and other contaminants such as antimony. While penalties can vary, they can be on the order of $70/dry metric tonne of concentrate per 1% of arsenic. Strategies used by miners to avoid the price penalties have been to blend clean and complex concentrates, and to remove arsenic from complex concentrates to achieve smelter limits. Arsenic can be removed from copper concentrates by the heat-induced decomposition of the predominant enargite mineral (Cu3AsS4) at ~700°C. Roasting at such elevated temperature is a commercially proven option, but still suffers from process, cost and environmental challenges. After roasting, the released arsenic sulfide fumes can be separated from most of the entrained concentrate dust in cyclones. Then, the As2S3 laden off-gas can be oxidized to generate a still volatile oxide (As2O3), which can be further separated from the residual concentrate dust in a hot electrostatic separator. Next, the off-gas can be cooled with air or water, to either deposit the arsenic oxide in a dry or dissolved state. Dissolved arsenic acid can be oxidized to As(V) and reacted with iron to yield a stabilized ferrihydrite precipitate or scorodite that can be safely disposed. In the case of dry arsenic trioxide, it can be mixed with reactants (e.g. iron) and fluxes before thermal stabilization in a glass matrix, thus eliminating the need for costly oxidation.

Jan 1, 2019

By Lutz Markworth, Wolfram Jaspers, Johannes Kottmann

PNEUFLOT® technology has been applied for the past 20 years in coal, ore and other minerals processing plants. During the last two years this technology has achieved a breakthrough with some 42 units being sold signifying a rising trend. »Humboldt Wedag Coal & Minerals Technology« has performed extensive research and development work over the last five years. The results of which were used to design a new fourth generation aerator. Humboldt Wedag, through its association with EKOF, can offer a holistic solution encompassing both flotation equipment and reagents. It is the only company in the world able to offer such a package. The association with EKOF strengthens the Humboldt Wedag product offering, especially as the company in-troduced pneumatic flotation cells to the South African market in the form of the PNEUFLOT®. Before starting pilot scale test work, a mineralogical analysis has to be carried out to determine the mineral com-position as well as the liberation grade. HW-CMT works together with independent institutes. Different reagent regimes can be tested in laboratory scale. Pilot machines, each packed in a 20? container, are available to carry out extensive test work at customers? processing plants. A group of engineers from HW-CMT is involved in the pilot test work. The flexible pilot machines are designed to cater for coal, ores and other minerals. The small feed rates of 7 ? 12 m³/h only means the pilot machines do not disturb the operation of process plants. Batch tests have to be carried out to determine the numbers of PNEU-FLOT® stages. New applications in iron ore, copper ore, platinum group minerals, rock phosphate and potash were suc-cessfully tested in the last three years. In applications where the feed material is very fine, PNEUFLOT® technology is able to achieve high recoveries with particle sizes where conventional technology failed.

Jan 1, 2007

By Wilbert J. Huff

[This is the fifth of a series of annual reports of the explosives Division, Bureau of Mines, United States Department of the Interior.3/ It deals particularly with work done during the period July 1, 1939, to June 30, 1939. The writer and the respective unit leader to whom credit is indicated have directed the various studies outlined.]

Jan 1, 1940

By G. R. Brough

"Today it is more important than ever to get the maximum possible return on capital invested in the processing industry. To this end the plant is often operated continuously and the choice of equipment is, consequently, extremely important.Screening spans a wide range of particle sizes and there are many different types of screening elements. The following types are common:1. Cloths and elements of rubber.2. Wire mesh screens with round wires.3. Wire mesh screens with profiled wires.4. Perforated steel plates.5. Elements of plastic.6. Gratings of steel beams.7. Gratings of iron rods.We would like to deal with two of these types namely rubber and briefly on plastics.We first introduced rubber screens to the Canadian Mining Industry in November, 1963. This stemmed from a conversation with the superintendant of one of Canada's largest screening plants containing 48 vibrating screens, with an average wire cloth life of 10 to 12 days. We contacted the manufacturer of rubber screen cloths who had supplied rubber screens to a mine in Northern Sweden for a 50,000 ton per day plant in 1951."

Jan 1, 1983

By J. B. Gayle

PRESENT flotation processes depend almost entirely on the buoyant properties of air bubbles to effect separations of mineral and gangue, but there is no convenient method for measuring aeration in flotation cells. Consequently the relation between aeration and cell performance has not been definitely established. In connection with a comparative study of kerosene and froth flotation processes, a modification of the displacement method' was developed in which air escaping from the cell surface is measured with a wet-test meter. The arrangement shown in Fig. 1 is satisfactory for use with a number of cells and is not critical, except that care must be taken to use connections and tubing large enough to avoid excessive back pressures. Attempts to use smaller tubing resulted in back pressures that caused displacement of the liquid level in the receiver, so that some air was lost around the sides, an occurrence readily visible when measurements were taken with only water passing through the cell. With the arrangement shown, the manometer indicated an average reading of about 1/2-in. water pressure. No loss of air was evident. Fig. 2 presents typical data for a standard Denver sub-A 24x24-in. unit cell operated at impeller speeds from 0 to 710 rpm. Each plotted point represents the average for five readings distributed over the entire cell surface. Readings were taken with only water passing through the cell. Results of this type have been used in a study of the influence of operating variables on cell performance and in detecting inherent differences in the operating characteristics of cells of various kinds. Although the information presented in Fig. 2 resulted only with water passing through the cell, the apparatus is suitable for use during flotation of coal when various reagents are present. Possible modi- fications that might prove convenient under special circumstances include varying the size and shape of the receiver and substituting a calibrated, inverted, water-filled carboy or other gas-measuring device for the wet-test meter. If such modifications result in excessive back pressures, some form of draft should be applied at the discharge end of the measuring system.

Jan 1, 1959

By J. L. Eakin

Systematic flooding was introduced into Nowata County, Okla., in May 1931. The results of this means of stimulating the nearly depleted Bartlesville reservoir in the county has been the subject of four Bureau of Mines Reports of Investigations.2-5/ This report presents a discussion of four full-scale water-flooding projects in the Delaware-Childers field and 1 pilot project in the Curl Creek field (fig. 1). All five plants have been in operation for only a few months. Although substantial increases in the rates of oil production have been obtained 1 by the injection of water, the projects are of particular interest at this time because of the novel methods of operation and new equipment that are being employed. One project utilizes a portable "package" plant designed for a pilot operation. All of the controls for this project are centrally located. The design makes it possible to remove the test plant to another location if the project is unsuccessful or if the unit is to be replaced by a larger plant. This project also utilizes diatomaceous-earth filters successfully for the first time and makes use of plastic pipe. Another novel feature of the operation is the aeration of Arbuckle limestone water through an airlift in the supply well.

Jan 1, 1955

TABAKOTO / SEGALA ? Annual gold production approximately 100,000 oz ? Debt free ? Unhedged ? Combined surface reserves 949,000 oz ? Combined 9 year life Tabakoto open pit reserve 568,000 oz (3.4m tonnes @ 5.26 g/t Au) Segala open pit reserve 381,000 oz (3.98m tonnes @ 2.98 g/t Au)

May 1, 2006

By M. Barsky, A. Govorov, E. Barsky

A study was conducted to determine the structure and lifting capacity of a two-phase stream in a vertical pipe at different distances from the point of introduction of the material into the instrument. Stream velocity was set at 2.8, 4.0, 4.8, 5.6 and 6.25 m/sec to ensure separation regimes. It was found that the llifting capacity of the two-phase stream exceeded that of pure air by a factor of three or more, and that in a turbulent regime the velocity curve displayed marked deformation, becoming more rounded and tending towards a parabola. The following formula was obtained for entrainment of a given size fraction under turbulent, laminar and transitional particle flow regimes:

Jan 1, 2003

By Michel C. Frippel

This section of the Minerals Yearbook reviews the minerals industries of 27 countries: the 12 nations of the European Community (Belgium, Dermark/Greenland, France, Germany, Greece, Ireland, Italy, Luxembourg, the Netherlands, Portugal, Spain, and the United Kingdom); 6 of the 7 nations of the European Free Trade Association (Austria, Finland, Iceland, Norway, Switzerland, and Sweden); Malta; the 8 Eastern European economies in transition (Albania, Bulgaria, Czechoslovakia, Hungary, Poland, Romania, and Yugoslavia); and the U.S.S.R. Western Europe Western Europe [loosely defined to include the 12 nations of the European Community (EC) and the 7 nations of the European Free Trade Association (EFTA)] is the single largest trading area and consumer of raw materials in the world. If Western Europe was at one time an important mining sector, it has now increasingly relegated the role of supplying minerals for its minerals processing industry to the more minerally endowed countries in North and South America, Africa, and Australia. In this regard, Western Europe is the most important determinant of raw materials consumption (and thus, indirectly, raw materials production). Western Europe has significant reserves of industrial minerals but has limited availability of metalliferous raw materials. It, therefore, imports significant quantities of the latter and ranks along with the United States and the U.S.S.R. in the production of refined metals. Nonetheless, there is an inherent tendency to underestimate the importance of Western Europe in the world of minerals, both as a minerals processor and raw materials buyer. The reason for this is that Western Europe is generally thought of on the basis of individual nations rather than as a whole. Viewed in this limited context, the United States, the U.S.S.R., and Japan appear to dominate the world economy. Viewed as one regional area, however, Western Europe includes the fourth (FRG), fifth (France), sixth (United Kingdom) and seventh (Italy) largest economies of the world, all bordering on one another. With the remaining 15 EC and EFTA countries, Western Europe has a land area approximately 40 % of that of the United States, exceeds the U.S. population by 50 % and has a gross domestic product about the same as that of the United States.

Jan 1, 1993

By SANDEEP KUMAR JENA

This paper reviews the recovery of potassium from different rocks and mineral sources. Global demand for potassium is rising steadily due to the growth of agricultural production. Fertilizer manufacture consumes the majority of the world’s potassium production, with other uses including those in the pharmaceutical, glass, ceramic, food and detergent industries. The availability of soluble potash (K2O) minerals, such as sylvite, kainite and carnalite, in countries like Canada, the United States, Israel and Russia makes them major potash producers, whereas agriculture-based countries like Liberia, Somalia, Central African Republic, Thailand, Indonesia, Malaysia and India meet their potassium requirements through imports only. In these countries, the huge availability of potassium-bearing rocks/minerals like nepheline syenite, feldspar, mica and glauconitic sandstone, containing around 4 to 17 percent K2O, brings up the prospect of commercial production of potassium. Potassium recovery from minerals/rocks is complicated due to the uniform distribution of potassium throughout the crystal structure. Different physico-chemical separation methods like bioleaching, chemical leaching, flotation and roast-leaching have been discussed for the successful recovery of potash values from these rocks/minerals. Although seawater is vastly available, the recovery of potassium from seawater using chemical precipitation, solvent extraction, membrane separation and ion-exchange methods is not cost-effective due to low concentration of potassium.

By B. J. Schat, A. W. O. Bots, O. S. Langhorst

Amsterdam City Council is building a new metro line, the North–South Line. The line passes under Amsterdam Central Station (a listed building) about 18m below street level. The retaining wall that has to be built underneath the existing building is an innovative construction consisting of two rows of steel piles interspersed with a solid mass of overlapping jet grout columns: a composite ‘sandwich’ wall. This paper gives an overview of the approach taken to designing (computational models) and building the retaining wall. Special attention is paid to the observational method used for the construction of the jet grout columns.

Jan 1, 2007

By Jon Y. Kaneshiro, Eric Dawson, Pooyan Asadollahi, Steven Hunt

This paper provides updates to the paper published by the lead author at RETC 2011 with a summary of developments in technologies, products, and approaches to corrosion analyses of gravity sewer tunnels and microtunnels. This paper presents approaches in evaluating degradation of reinforced concrete liners. Also, the carbon footprint of conventional concrete liners and alternative “green” liners are compared and their life cycle costs are considered. A few case histories from the past decade are provided indicating the latest and emerging trends in liner protection.

Jun 13, 2023