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By Harvey S. Mudd

WHEN talking about Europe it is well to endeavor to keep politics and economics apart but they have become so intermingled in recent years that the discussion of one topic inevitably leads to the other. Economic influences formerly prevailed over politics but today national and international economies are governed by political forces. Commerce in raw materials, food, and manufactured products is now so restricted by governmental controls that the capacity of the world to produce and to consume, to exchange goods and to pay for them, cannot be gauged by the past or predicted by a multitude of experts. In prewar days there were some yardsticks but today there are none. Thus it is hazardous to make forecasts, for in all fields of human effort the world has been cast upon an uncharted sea.

Jan 1, 1947

By Thomas A. Wheeler

The reagents commercially used in coal flotation and their roles are reviewed and discussed According to their function the reagents are divided into often overlapping groups: 1. Collectors 2. Frothers 3. Conditioning Reagents Frothers have by far the largest effect on the amount of coal recovered They act not only in their traditionally accepted function of “bubble makers”, but in coal flotation they serve in a seldom acknowledged role of collectors. A lab flotation study on four samples of different coal ranks shows how these react to various frother families and proves that no froher is the optimum reagent for all types of coal. The advent of new technology in flotation equipment in the past decade has resulted in various novel designs of column cells, Jameson and Centrifloat™ cells, air-sped hydrocylones, etc. All should require special frothers or blends of frothers to meet their specific needs.

Jan 1, 1994

By A J. Daniels

Macraes Mine is a large-scale open-cut and underground gold mine located in Central Otago, on the South Island of New Zealand. This paper presents the role of geological mapping in the grade control process at Macraes Open Pit as a case study, and demonstrates how systematic geological mapping can add significant value to the mining cycle. Geological mapping has proved to be a valuable foundation for orebody interpretation and analysis.Practical applications and lessons learnt are summarised, including predictive control of the orebody, improvement of geotechnical modelling, and identification of further exploration targets.

Aug 22, 2011

By G. T. Lineberry, L. Adler

Due to safety-imposed constraints on clearances for mobile bulk handling equipment, it is necessary to optimally select a unit based on speed and size. The unit cannot be both large and fast. Since output is proportional to both size (or capacity) and speed, the combination must be carefully examined to maximize output. A simple graphical procedure and a calculus-based solution are presented to accomplish this. While the procedure applies to all mobile bulk handlers, as an example of the solution technique, attention is focused on shuttle cars. Background Major variables To fully define a bulk handling problem, the conditions, equipment, and activities must be characterized. The conditions and activities, when lumped together, are termed "encumbered space," since they "act to impede motion, as with a burden" (Lineberry, 1979). The insertion of mobile bulk handling equipment into what is already a difficult set of conditions and activities compounds the state of encumbrance, as limited space is competed for by many normal and life support systems. Long (1972) recognized the effects of design criteria, including road width, on haulage vehicle speed and, therefore, on production. Velocity -clearance curves Velocity-clearance curves are either available or can be constructed in the field. A preliminary set of curves for average conditions and activities is shown in Fig. 1, where clearances are only for the side of the vehicle (Lineberry and Adler, 1984). These curves set the safe speed limits for a vehicle operating at given clearances, under given conditions and activities. When feasible, velocity-clearance curves should be constructed through field measurement and observation. Curve construction should also consider haulway roughness, distances, and operator skill, as well as loading and dumping characteristics. It should be noted that haulage capacity determination is a total systems problem, not one just dependent on velocity and clearances. Production requirements and company capabilities also influence capacity determination.

Jan 10, 1985

By J. G. Thompson

IRON, iron everywhere, but hardly a particle of pure unadulterated iron for the metallurgist to use as a base for the protean characteristics that he develops in the alloys of iron-the modern steels. Iron, next to aluminum the most abundant metal in the crust of the earth; one of the oldest metals known to man and serving him as the most indispensable metal in both war and peace; yet man's knowledge of its properties is based on specimens that are not pure and hence probably differ considerably in their properties from the truly pure metal. Purification of iron has brought about startling changes in its electrical and magnetic properties and has modified its behavior in changing its crystal form with temperature, the basis of the heat-treatment of iron. So both the research metallurgist and the metallurgist of the steel plant are intrigued by the possibilities that might unfold were 100 per cent pure iron available in sufficient quantities to determine its properties.

Jan 1, 1940

This paper describes the new iron and steelmaking process recently commissioned at NZ Steel. Ironsand mined and concentrated at Waikato North head is slurry pumped 18 km to the company's Glenbrook works. Ironmaking includes the direct reduction process pioneered at Glenbrook in the 1970s and a new continuous electric melter. The molten, high carbon pig iron produced is then fed to a vanadium recovery unit and on to the KOBM oxygen steelmaking vessel. Steel is cast into billets or slabs. The new plant, which is the first stage of a fully integrated works at Glenbrook, raises New Zealand Steel's production capacity from 150 000 t/y to 750 000 t/y.

Jan 1, 1986

By Forrest T. Moyer

THE injury data and experience in this bulletin are presented in three general sections. The first section contains general and detailed data relating to 1948 injury experience in bituminous-coal and Pennsylvania anthracite mines, separately and combined into totals for all coal mines. The related employment, worktime, production, and productivity data are given in each breakdown of the statistical data. Tables 1 through 22 constitute a subsection and present statistics on number of injuries, frequency and severity rates, average severity, detailed and major causes of injuries, injury records of the coal-producing States, distribution of injuries by part of body, and distribution of injuries by days of disability. Tables 23 through 45, the second subsection, present injury experience in bituminous-coal mines by various selected factors of physical or operating conditions that ma contribute to the occurrence of injuries. The degree of mechanical loading, productivity, size of mine by number of men working and by tonnage mined, thickness of bed, length of shift, number of shifts, type of cap lamps, rating of mine as gassy or nongassy, type of ventilation, and combinations of these factors influencing mine safety are presented in this group of tables. Similar data on Pennsylvania anthracite mines are listed in tables 46 through 63, which comprise the third subsection. The second section of the report contains the generalized annual injury records of bituminous-coal, Pennsylvania anthracite, and all coal mines from the earliest available data through 1948. Tables 64 through 97 list the number of fatal and nonfatal injuries, injury rates, and causes of injuries on an industry basis, the long-term injury records of each coal-producing State, and the related employment, worktime, and production data.

Jan 1, 1952

By M. Cai

Transformation of the measured borehole deformations induced by stress relief relies on the traditional assumption that the rock is continuous and homogeneous. Systematic and quantitative tests were carried out to check the performance of devices commonly used for measuring borehole deformations within different types of discontinuous rock conditions. Test results provide a reliable basis for considering the influence of discontinuities on in situ stress measurement and for choosing the best measuring device for a given rock type and condition.

Jan 1, 1998

By P. Gelfi, J. Vanderbeek, J. Enriquez

"The Cerro Verde copper-molybdenum mining complex is located near Arequipa, Peru. A 108,000 t/d copper concentrator (C1 concentrator) commenced operation in late 2006 and was debottlenecked to a 120,000 t/d capacity in 2011. A feasibility study, initiated in May 2010, assessed the potential for expanding the processing rate of the large Cerro Verde sulfide reserve via the installation of a second, stand-alone, concentrator (C2 concentrator) capable of processing a nominal 240,000 t/d ore. The feasibility study was successful and the project advanced through engineering, permitting and construction. Ramp up to nameplate capacity was ahead of schedule. The overall project was completed on schedule and within budget. The details of the project and supporting components are described. The design philosophy and design basis of the concentrator facilities are discussed as are factors that influenced the concentrator layout. Risk mitigation features included in the design are reviewed. The factors that drove the successful and rapid ramp up to nameplate capacity are discussed. Operational experiences in the first year of plant operation and project lessons learned are described. INTRODUCTION/BACKGROUND Sociedad Minera Cerro Verde S.A.A. (SMCV) operates a copper mine near Arequipa in southern Peru. Small scale operations operated intermittently until 1970 when the deposit reverted to the ownership of Minero Perú S.A (Peruvian government). Minero Perú S.A. commenced mining and processing of oxide reserves in 1972 and placed an SX-EW plant into production in 1976. The ownership of the property has changed hands several times over the years. Minero Perú sold Cerro Verde to Cyprus Climax Metals in 1994. Cyprus was acquired by Phelps Dodge in 1999. Freeport-McMoRan (FCX) acquired Phelps Dodge in 2007. Several studies were undertaken during the 1990’s that tried to establish the economic justification to process the large primary sulfide resource that underlies the surface oxide deposit. None of these studies produced an economic conclusion until a feasibility study was completed by Phelps Dodge and SMCV in 2004. This study provided the economic justification for the construction of a 108,000 t/d concentrator during 2005 and 2006. The key to the success of this study was identifying a water source that was sufficient to support processing economies of scale. Concentrator operations commenced in late 2006. The original design production rate of 108,000 t/d was achieved on a 30 day moving average basis on the 266th day after ore was first introduced. During 2009, studies and evaluations were performed that had the objective of addressing observed concentrator bottlenecks to allow a production rate of 120,000 t/d to be achieved. The 120,000 t/d figure represents the sustainable production limits associated with the installed primary crusher and tailing thickeners which would have been prohibitively expensive to upgrade. Debottlenecking activities were implemented during 2010 allowing sustained production rates of 120,000 t/d to be achieved."

Jan 1, 2017

By J. M. Bowen, P. Wemyss

"Gold losses to natural carbonaceous matter during cyanide leaching have been investigated for over a century. The variation in the severity of the problem from one ore to another has led to a range of different processes being implemented at different mine sites. Most commercial options utilise one or more of the following processes: roasting, carbon pre-flotation, organic blinding, CIL, chlorine passivation, pressure oxidation, biological passivation, elevated temperature CIL, RIL and thiosulfate. This paper provides a background to identify the most appropriate process or combination of processes for a particular ore. It also presents information on how these processes may be implemented, drawing on information in the literature and from current or recent applications at operations such as the following: Stawell, Kumtor, Penjom, Twin Creeks, Macraes Flat, Kittilä, Fosterville, Inata, Carlin, Goldstrike, and Jerritt Canyon. Various process options have been dismissed, or deemed unsuccessful due to limited knowledge available on the strengths and weaknesses of the different options and their implementation. The authors have collectively been involved in flowsheet development and project implementation in four commercial plants that have treated preg-robbing ores.INTRODUCTION Cyanide processing has been the mainstay of gold recovery for well over a century. It is generally a very effective process with over 90% recovery on free milling ores, but complex and refractory ores may only give 0–50% recovery with conventional processing (La Brooy et al., 1994). People have written about gold losses to natural carbonaceous matter during cyanidation for over a century e.g. Feldtmann, (1915). The earliest reports related to African operations, but the issue has since been reported in Canada, North and South America, Australia, Russia and China. The phenomenon is usually referred to as ‘preg-robbing’ dating from the times before the use of granular activated carbon for gold recovery, when gold was lost from the pregnant solution before it could be separated from the leach solids and recovered by cementation. Many excellent reviews have been published e.g. Dunn et al. (2013), summarising the options considered and where they have been applied commercially."

Jan 1, 2017

By R L. Brathwaite, R Carver

The REGCHEM (Regional Exploration Geochemistry) database of open file mining company data, managed by GNS Science, has recently been upgraded with the compilation of additional data, especially for the Otago region (see http://maps.gns.cri.nz/website/minmap). In June 2007, data compiled for the Otago region included more than 2000 stream sediment samples from 19 surveys, more than 800 BLEG (bulk leach extractible gold) samples from 12 surveys and a few pan concentrate samples. The stream sediment samples were typically analysed for Au and As, and in many cases for other elements including Cu, Pb, Zn, Sb, W and Mo. The BLEG samples were analysed for Au and in some cases also for As. The main exploration target was mesothermal gold deposits in the Otago Schist, although one survey of the Otago Peninsula targeted potential gold deposits associated with the Dunedin volcanic complex. Geochemically, the mesothermal gold deposits are characterised by anomalous As and Au, with some also characterised by anomalous W and Sb, and these four elements are the best pathfinders in stream sediment geochemical surveys. The introduction of lower detection limits in Au analyses in the more recent stream sediment surveys and in the BLEG surveys enables the use of this element as the primary pathfinder for mesothermal gold deposits.

Jan 1, 2007

By R. Gensemer

A number of state and federal agencies are calling for development of aquatic life criteria for conductivity. These aquatic life criteria or ?benchmarks? are based on observed correlations between conductivity and benthic macroinvertebrate community composition, generally measured by composite metrics or indices. However, development of an aquatic life criterion for a composite variable like conductivity is made difficult by a number of factors. Based on a database from West Virginia, observed patterns of invertebrate community composition versus conductivity may instead be related to a combination of abiotic (e.g., ionic composition, habitat) and biotic (e.g., life history, colonization potential) factors. Many benthic invertebrate taxa also do not respond to increasing conductivity in a consistent relationship. Many states have determined that a composite variable, like conductivity or TDS, is not appropriate for criteria development, as many studies have shown that toxicity varies as a function of ion composition and can be mitigated by elevated hardness. We conclude that the relationships between conductivity and changes in benthic macroinvertebrate community composition are neither strong nor reliable enough to warrant derivation of a criterion based solely on conductivity.

Jan 1, 2011

Geophysical Abstracts 1 - 86 wore issued in mimeographed form by the Bureau of Mines; Abstracts 87 - 111 were published in bulletins of the Geological Survey; Abstracts 112 - 119 were issued in mimeographed form by the Bureau of Mines as Information it ion Circulars 7256, 7257, 7267, 7273, 7285, 7292, 7303, and 7310. 1. GRAVITATIONAL METHODS 7786. Barton, D. C.3/ Case Histories and Quantitative Calculations in Gravimotric Prospecting. Am. Inst. Min. and Meat. Eng., New York, Tech. Pub. 1760, 1944, 49 pp.

Jan 1, 1945

By S. A. Richards

Business planning in the coal' industry revolves around the production and quality forecast. It is difficult to accurately estimate costs and revenues until the production forecast is made. At mines where production comes from multiple sections, quality is tied to each section's production. Blending becomes a part of the planning process. In order to respond to rapidly changing business climate, a reliable program is needed to accurately forecast the effects of changes in key parameters affecting the production. This paper discusses an efficient, intuitive, and economical approach to underground coal mine planning program which uses a PC-based relational database as the programming platform to forecast production and quality. The program was developed at a major coal company. The relational nature of the production planning data, the programming algorithm, and the underlying principles are discussed in this paper.

Jan 1, 1994

By I. AITKENS

The basic mining law of Cuba is contained in the basic Spanish mining decree having the effect of law December 29 , 1868. This legislation has remained substantially unchanged , with the exception of a few minor administrative changes made by the present Government . These changes provide for the register of mines , oil wells , and operations of such nature , and also provide for the keeping of records showing the value of minerals taken out . By Royal decree of April 17 , 1883 , the law of mines enacted for the Peninsula ( Spain ) on July 6 , 1859 , and the General Bases of December 29 , 1868 , were declared in force in Cuba . In order to encourage the mining of iron org , in 1883 the Crow of Spain issued a royal decree to the following effect.

Jul 1, 1931

A series of laboratory evaluations examined the impact of water spray pressure, curtain setback distance, and external and underboom spray use for controlling respirable dust levels and sulfur hexafluoride tracer gas concentrations around a continuous mining machine. This mining machine was equipped with a flooded-bed dust scrubber and was positioned in the box or slab cut. Exhaust line brattice was used for all tests. Dust levels were measured in the return airway and at locations representing the operators of the continuous mining machine and the standard and off-standard shuttle cars. Increasing water pressure or using the underboom sprays produced no significant impacts on dust levels, although their interactions did produce some significant impacts. Increasing curtain setback distance often elevated dust levels, likely by reducing the amount of airflow reaching the face. Use of the external sprays created additional airflow around the mining machine that pushed the dust cloud past the scrubber inlets. This significantly increased dust levels at all sampling locations. Tracer gas levels were measured on the off-curtain and curtain sides of the cutter head and in the return airway. Increasing water pressure generally led to significantly increased gas levels on the curtain side, although a slight decrease was observed on the off-curtain side with the machine in the box cut. Increasing setback distance elevated gas levels on both sides of the cutter head and in the return by limiting the quantity of ventilation airflow reaching the face. Use of the external sprays provided additional airflow along the off-curtain side of the machine, significantly reducing gas levels in this region. These sprays adversely impacted the dilution and removal of gas on the curtain side of the cutter head. Use of the underboom sprays adversely impacted gas levels on both sides of the cutter head. Use of the external sprays provided the best control of respirable dust and face gas concentrations. The smaller increases in miner operator dust levels produced by these sprays were offset by larger reductions in face gas levels on the off-curtain side of the cutter head. Although the underboom sprays minimally impacted respirable dust levels, use of these sprays was not recommended because they increased face gas levels.

Jan 1, 2007

By R. E. Wagner

Consistent increase has been the mark of North American potassium (K) consumption. In 23 of the last 25 years there was upward progress The pace of usage has quickened in the past three or four years This, together with a predicted accelerated future demand, has created unprecedented interest -and activity in the potash industry. Potassium enjoyed a ninefold increase in consumption from 1940 to the present time in North America (Figure 1). Since 1950, it increased from just over a million tons of potash (K20) annually to nearly three million tons in 1964. World-wide usage exclusive of mainland China is now about 10 million metric tons. Some predictions call for another doubling in consumption in the next 10 to 15 years, About 20 percent of the four million tons of K20 produced in North America is now exported overseas and this percentage is likely to increase in the years ahead. Ten years ago, exports represented only 3-1/2 percent of total K2O production from this continent.

Jan 1, 1966

By A. Timur

Fluid flow properties of porous media have long been of interest in such varied disciplines as geology, geophysics, soil mechanics, and chemical, civil, and mechanical engineering. This interest has resulted in numerous models of porous media that have been proposed, tested, and found to be useful under, at best, only special circumstances. A critical review of most of these models is given by Scheidegger. 1 The application of each new tool to the study of porous media has helped to test some of the existing theories and to form new ideas based on the new parameters being measured. In the application of nuclear magnetic resonance (NMR) techniques to the study of the properties of fluids in porous media, the theoretical studies of Korringa et al.2 resulted in a model for the relaxation of spin polarization of protons in a hydrogenous fluid in a pore of a solid. Seevers3,4 verified this model, established a method for measuring the surface-to-volume-ratio distribution in a porous medium, and proposed a technique for determining specific permeability in sandstones. In the present investigation, the uses of NMR methods are extended and a simple model of porous media is developed from an analysis of pulsed NMR measurements. In this model, the pore spaces of a porous medium are divided into three groups on the basis of their surface-to-volume ratios. To evaluate predictions of the NMR model, laboratory measurements of spin-lattice relaxation time, porosity, permeability, and residual (irreducible) water saturation were conducted on more than 150 sandstone samples obtained from four oil fields in North America. Applications are discussed for estimating the volume of movable fluid, ?p, and the specific permeability, k, of sandstone samples. The former parameter, which can be considered as producible porosity, is expressed by ?p = [1 -- (Swr/100)]? , .... (1) where + is porosity in percent of bulk volume and Swr is the residual (irreducible) water saturation in percent of pore volume at a capillary pressure of 50 Psi. Fast, nondestructive laboratory methods are described for determining porosity, movable fluid, and permeability of sandstone samples from measurements with a pulsed NMR (spin-echo) apparatus. Procedures are given for adapting these methods to samples of irregular shape and small size. Theory General In the Korringa, Seevers, and Torrey2 (KST) model the observed decrease in the spin-lattice relaxation time, T1, of protons of a hydrogenous liquid contained in the pore spaces of a porous solid is attributed to an increase in the correlation time for the random motion of the water molecules and to the presence of paramagnetic centers at the liquid-solid interface. This KST model predicts the observed relaxation time of a hydrogenous liquid in a pore of a solid through

Jan 1, 1970

By Forrest T. Moyer

The National Safety Competition was inaugurated in 1925 by the Bureau of Mines, U.S. Department of the Interior, in cooperation with the Explosives Engineer. In the first nationwide contest, 210 mines and quarries were enrolled. In 1962, the thirty-eighth anniversary of the competition, 910 mines and quarries were enrolled. These participating plants were worked a total of 133,292,989 man-hours. Of the enrolled plants, 415 achieved injury-free operations for the year, the largest number of perfect safety records in the history of the contest.

Jan 1, 1964

The key issue which determines the use of imaging for explosives and mining research is the question - `What information will I gain by using imaging technology?' This paper will address that question from the point of view of a researcher and cameraman working in industrial imaging and photography. The paper will establish a common set of reference standards for high speed imaging and photography which researchers can apply when deciding which type of imaging technology is appropriate. It will present an overview of current image analysis technologies and practices in use across a range of appropriate scientific fields and draw lines of commonality of approach between these fields and the field of explosives and mining analysis and research. Further to this, the paper will examine the different technologies from an image quality reference point, ease of operation, cost, and reliability parameters. Finally this paper will present an argument for the hybridisation of established and new technologies which could provide a more beneficial approach to the use of imaging as a tool of research and analysis in the explosives and mining industries. This will include a novel approach to high speed filming and analysis in the field which should deliver high quality images in a time frame which is more appropriate to urgent action and solutions.

Jan 1, 1995