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This report is the 25th in a series summarizing Bureau of Mines research and technologic work on coal and related investigations, and the 7th of these reports to be issued on a calendar-year basis.3 It reviews briefly work in progress during 1960, and furnishes references to publications by Bureau personnel during 1960 and also to a few older papers that were not cited in prior reports of this series. Details about some of the researches mentioned can be found by referring to the publications cited in the footnotes or in the further list in the Miscellaneous section; other phases of work are reported here for the first time and will be covered in more detail by later publications, Coal programs of the Bureau of Mines extend over the wide range of theoretical and applied studies indicated by the table of contents. Fundamental research on coal structure and on the properties of coal will, over a period of time, increase the general knowledge about coal Which scientists and engineers may use in answering practical questions and in solving problems in the mining and utilization of coal. More applied studies are conducted in connection with the developement and evaluation of new mining techniques and the effective processing and utilization of coal and of coal products. Health and safety activities, analyses of coal being mined, and technical advice and assistance to Federal agencies in connection with fuel and boiler-water problems are among the practical services handled by the Bureau.4 5

Jan 1, 1962

By Rolf B. Pedersen, Ana Filipa Marques, Ingunn H. Thorseth, Ingeborg Okland

"Deep sea mining of polymetallic sulphides will change the physical and chemical conditions at the seafloor by creating scars when sulphides are removed, and potentially also by deposition of mine tailings at the seafloor. These changes will impact the existing ecosystems at the seafloor in and around the mined areas. Seafloor Massive Sulphide deposits that have been exposed to oxic seawater weather into Fe-metal-oxyhydroxides. However, the rates of weathering and release of heavy metals and other toxic compounds to the environment from freshly exposed sulphides in a deep-sea environment are not well studied.During a cruise to the Arctic Mid-Ocean Ridge in the Norwegian-Greenland Sea in July 2014 we will initiate in-situ experiments investigating the microbiological and geochemical processes involved in the weathering of freshly exposed massive sulphides deposits in a natural environment. This will be done by creating scars in naturally occurring sulphide deposits and by deploying weathering experiments at the seafloor. The sites will be revisited and re-sampled in 2015. The mobility and fate of heavy metals will be one of the main concerns of the study as well as constraining the time it will take for exposed sulphides to return to the chemical state present prior to mining. In this presentation we will present the experimental framework and the preliminary results from the July 2014 cruise. This project is part of the EU funded MIDAS (Managing impacts of deep sea resource exploitation) project."

Sep 1, 2014

Application of Kriging in Approximations of Grained Materials Characteristics Distribution Functions

Sep 13, 2010

By Rossiter W. Raymond

(Canal Zone Meeting, November, 1910.) THE death of Professor Blake removes the oldest of American economic geologists and mining engineers, and deprives this Institute of one of its, earliest and most illustrious members. To many of us it brings a personal loss also, the loss of a friend. William Phipps Blake was born June 21, 1826, in New York City. -His father, Elihu Blake, was a surgeon-dentist of eminence, a direct descendant of William Blake, who settled in the Massachusetts Bay Colony about 1630. He was prepared for college at private schools in New York, and entered the Sheffield School of Yale, where he was graduated as Ph.B. in the chemical course, class of 1852, the first graduating-class of the institution. In the same year he became chemist and mineralogist of the New Jersey Zinc Co., and chemist of chemical works at Baltimore, Md. In 1853, lie started the Department of Mineralogy of the World's Fair at New York City. In 1854, 1855 and 1856, he was mineralogist and geologist of the United States Pacific Railroad Surveys of Williamson, Pope, and Whipple, and for the War Department at Washington. His writings, during this period comprise reports on the geology and mineralogy of California and other parts of the Southwest, and constitute well nigh the earliest scientific accounts of the regions described. One of them. was a translation of the Resume and Field Notes of Jules Marcou, of Whipple's expedition. From 1856 to 1859, he was engaged in explorations of the geology and mineral deposits of North Carolina, :and other parts of the country. In 1859, he became editor and proprietor of The Mining Magazine. This was a monthly periodical, founded in 1853 by W. J. Tenny, who conducted it until 1858, when it passed into the hands of Thomas McElrath, a New York publisher, and appeared in May of that year as The Mining and Statistic Magazine, with the name of

Sep 1, 1910

By A. J. Romeo

The Old Hickory heavy mineral ore body, which lies within the Fall Zone of south central Virginia, has been mined since 1997. There are many differences in this deposit when compared to humate-laden mineral sands mines of southern Georgia and Florida. These differences include an abundance of kaolin-rich clayey sands, highly concentrated and iron-colored heavy mineral sand units, and a base of mineralization that is undulating. For these reasons, the selective approach of dry mining with track excavators is ideal. Grade control in this deposit uses traditional panning techniques and requires an intimate working knowledge of near-by drilling data. Mine geologists train equipment operators to recognize the base of mineralization by such characteristics as a stark color change, significant changes in grain size, and/or considerable, recognizable shifts in the concentration of heavy minerals. The regular pattern of mine site drilling does not always prepare the geologist and digging crews for occurrences of near-vertical contacts between the saprolite basement and the ore sands. These deformed areas, combined with undulating and pinching ore zones, require close monitoring and flexibility by the geologist and the mine operators.

Jan 1, 2005

By J. D. Miller

Characterization of feed material with respect to expected concentrate grade and recovery is fundamental to the design of improved separation efficiencies and to achieve sustainable development in the utilization of our mineral resources. An important reference point for this characterization is the liberation-limited grade/recovery curve which represents the perfect separation, the best separation which can be achieved for a given feed material limited only by the extent of liberation. Now, liberation-limited grade/recovery curves can be determined based on 3D mineral liberation analysis of feed material. Thus, actual separation efficiencies can be compared to what might be expected for a perfect separation limited only by the extent of liberation. It is shown that 3D mineral liberation analysis based on X-ray micro CT (XMCT) is preferred to 2D section analysis which overestimates the extent of liberation. By way of example, procedures and experimental results are presented and discussed for feed material in the case of phosphate rock flotation.

Jan 1, 2009

By Hans von Michaelis

"INTRODUCTIONThe renaissance in gold and silver recovery technology has continued to unfold and it is appropriate to review some of the useful new technologies as well as try to identify some of the industry's future needs and frontiers.The remarkable strengthening in the US dollar has resulted in a relatively low gold price in US Dollars of around $310/oz at the time of writing and silver at $6.25/oz. This general softening in the dollar prices and the recent confusion as to environmental compatibility of cyanidation tailings and effluents, has led to a slowdown in announcements of new operations. Another reason for the slackening off in the USA is that in the past few years a large part of the capital has come from oi I and gas companies that now seem to be losing interest in mineral ventures, and foreign investors for whom the dollar is becoming out of reach. In the author's opinion this represents an unprecedented window of opportunity.Elsewhere in the world where local currencies have weakened, the price of gold is at or close to its all time high.For example, in South African Rands, the gold price was R571.00/oz when the rand was US$1.47 and the gold price reached US$800. Now at US $309/oz and with the Rand at US$0.51 = Rl .00, the local gold price is R600. The price of si Iver in Mexican pesos is not much less than it was when silver reached US$50/oz. Gold, and silver prices in local currencies outside North America are still buovant and at levels where additional investment in new projects is more encouraging.Even in Canada where the dollar is worth about US$0. 75, this provides a smaller but significant cushion compared with US operations. Considering the present strength of the US dollar and even the Canadian dollar relative to many other gold producing countries, there should be significant investment opportunities at today's prices. Mining companies have started to descend on Brazil, for example, where in a matter of just a few years annual gold production has increased from 10 to 70 tons. In South Africa, a Canadian company backed by Swiss financing has been able to take over a Witwatersrand gold mining operation and is installing a huge new tailin9s retreatment plant to process about 1 million tons per month of tailings."

Jan 1, 1985

By F. Parada Torres

Xstrata Tintaya S.A. opera el yacimiento a tajo abierto y procesa el mineral en dos plantas: Planta Concentradora de Sulfuros y Planta de Lixiviación de Óxidos, donde anteriormente consideraba al mineral mixto complejo como intratable en la planta concentradora, por lo que se le destinó a ser tratado como óxido marginal en la planta de lixiviación. En este sentido, el presente texto describe el nuevo tratamiento al mineral complejo en la planta concentradora. De forma que se busca definir las variables geometalúrgicas del mineral de Chabuca Norte, optimizar los procesos metalúrgicos del mineral mixto mediante la investigación geometalúrgica, así como correlacionar el entendimiento de la geología y alteraciones del yacimiento con los procesos metalúrgicos y crear valor mediante la optimización de la tasa de tonelaje de tratamiento y el incremento del porcentaje de recuperación de cobre en el proceso.

Sep 12, 2011

By Olli Aulio, Outokumpu Oy

"GENERALThe Outokumpu Company is today an important European producer of metals from its own mines: copper nickel cobalt, ferro chrome and zinc being the main products. In 1972 about 4 million tons of ore was hoisted from eleven mines.Outokumpu Oy has gained experiences on the various aspects of on line computer control since 1968. This knowledge has been combined to develop a standard computer control package for concentrator control. Before the development of computer control package was started Outokumpu Oy had three large computer control systems. The first system was at the Pyhasalmi Concentrator, thee second at the LokkolaPlant, and the installation of the third system at the Vuonos Concentrator was just started.The characteristics of general computer software packages - both control and executive ones - were thus well-known as well as the practical usage of control theory. Furthermore Outokumpu had developed the Courier analyzer which included a so-called minicomputer. This project had given experience both 1n totally self made real tire executives and in computer hardware and peripheral d=vices. The instrumentation of the Outokumpu concentrators was designed and installed traditionally by the engineers of Outokumpu themselves."

Jan 1, 1973

By L. J. Olivier

The possible closure and subsequent flooding of South Deep Gold Mine?s (SD) neighbouring Randfontein Estates Limited No. 4 Shaft (REL 4) necessitated the construction of five concrete plugs in the connecting tunnels to prevent the ingress of groundwater into REL4 from flooding SD. This paper describes the proposed controlled flooding of REL 4, the planned in-service monitoring of the five plugs and the water barrier between REL 4 and South Deep Mine, and the long-term maintenance of the plugs and rock mass in the immediate vicinity of the plugs.

Jan 1, 2006

By D. Shin

The gold leaching using cyanide from ore or waste has been almost universally in use [1]. Recently, biological gold bioleaching using cyanide producing bacteria, e.g. Chromobacterium violaceum, Pseudomonas fluorescens, or P. aeruginosa, has been investigated as environmental friendly and cost effective method. Among them, C. violaceum has been reported as effective cyanide producing bacterium on gold leaching [2, 3]. C. violaceum produces cyanide using glycine as a direct precursor and subsequently detoxify the cyanide by ß-cyanoalanine synthase [4]. However, until today only 0.026 ? 16.9 mg/L of cyanide production in YP medium has been reported in the literatures by C. violaceum [4-6]. Comparing with adding cyanide chemical, biogenic cyanide concentration is lower than the cyanide concentration added in traditional cyanidation. Since cyanide also forms complexes with a number of other elements such as iron, nickel, zinc, silver, copper, and platinum, it is very important for gold recovery to investigate the enhancement of biological cyanide production and set optimal experimental condition. Most of early studies on gold bioleaching by C. violaceum have been performed to investigate gold leaching mechanism using gold powder, and recently various resources such as ores, electronic scrap, and printed circuit boards of waste electronics [7]. Few studies have dealt with gold bioleaching from low-grade ore. In this research the feasibility of gold bioleaching by C. violaceum from low-grade ores containing gold was evaluated and fundamental study was performed for further scale-up study. The aim of this study was to improve the potential of gold bioleaching by C. violaceum from gold-containing ore; in particular, enhancement of biological cyanide production.

Jan 1, 2012

The corrosion behaviour of a low carbon steel was investigated in synthetic seawaters with and without Sr2+. It was found that strontium substitutes for calcium in aragonite, rather than precipitating as discrete strontianite (SrCO3). The aragonite deposits that formed in the presence of Sr2+ were finer than those that formed in the absence of Sr2+. It is believed that an increase in the strontium content of aragonite induces a decrease in its solubility, which in turn results in a higher nucleation rate of the precipitates. Furthermore, the growth rate of aragonite is decreased by the presence of Sr2+in the solution. It is concluded that Sr2+is an essential ingredient in any artificial seawater when calcareous deposits are investigated on steel. Keywords: corrosion, seawater, calcareous deposits, strontium, aragonite.

Jan 1, 2007

By M. Abdellatif

Keywords: Magnesium, pyrometallurgy, Mintek Samples of crude magnesium produced by the Mintek Thermal Magnesium Process were refined in two stages. The first stage consisted of co-melting of batches of the crude metal and MgCl2-KCl flux (cleaning), followed by stirring at 30 rpm for 30 minutes and settling of the sludge (mixture of molten salt and solid impurities) from the magnesium melt. The operating temperature was 680?730°C. Most of the contained calcium and significant proportions of iron and silicon were transferred into the sludge phase, which left a metal containing, on average, 950 ppm Si, 470 ppm Fe, and 230 ppm Ca. In the second stage, small-scale refining tests were conducted on cleaned samples from the first stage, as well as on crude magnesium. FeCl3 was used as the refining agent. These tests were carried out at 715?760°C with various amounts of the refining agent. The refined metal was suitable for the production of various magnesium alloys, particularly AZ91D.

Jan 1, 2006

By J. Allaire, P. N. Muteb

The Meadowbank mine is operated by Agnico-Eagle Mines Ltd. and is located in the Kivalliq District of Nunavut in northern Canada. The process plant operates presently at a throughput of 11,500 tpd with gold grade varying between 2.9 and 3.6 g/t. The ore supplied to the process plant come from two different open pits and it expected to come from a new open pit early 2014. The ore is mid-hard materials so the feed size ore have a bigger impact on the throughput. The average gold recovery is 94.0% with about 15-30% of gold recover from the gravity circuit. The Meadowbank mine commissioning started in February 2010 utilizing a flowsheet consisting of one stage of crushing followed by primary and secondary grinding. The commercial production began in March 2010. During the commissioning several difficulties were observed to reach the designed throughput of 8,500 tpd. It was evaluated to insert a second stage of crushing. The insertion of the secondary crushing have two objectives, first to reach easily the process plant design throughput as well as to evaluated the mill capacity increasing. The process plant team evaluated various expansion alternatives eventually deciding to install a secondary crusher, increased the SAG and Ball mills motors capacities and maintain the rest of the process unchanged. Early 2011, with the improvement in the gold markets, decision was made to install the secondary crusher between the primary crusher and the primary grinding. The process plant continued to operate on the initial design until early June 2011. This paper presents the SAG mill throughput increasing from the designed tonnage of 8,500 tpd to 2012 targeted tonnage of 11,500 tpd, secondary crusher commissioning and the difficulties to operate in Canada Artic (Nunavut).

Jan 1, 2013

By Wilson D, Kirkland J

Compressed air energy storage (CAES) uses low cost off-peak energy to compress air and pump it into pressurised underground storage. Expanding the air through a modified form of gas turbine generates electrical energy when required. While generating power, a CAES station consumes approximately one-third of the gas required for the equivalent installed capacity of a conventional gas turbine. Air can be stored in underground rock caverns, caverns in salt domes, or in aquifers. Existing CAES power stations use caverns mined out of salt domes. Aquifer storage for CAES has been proposed, but not yet implemented. The groundwater in the aquifer would be displaced during air injection and when required the air would be extracted using the natural hydro-static pressure. Victoria has no salt domes, but has aquifers onshore in the Gippsland Basin with geological dome structures of suitable depth, discovery pressure, porosity, permeability and caprock for CAES development. Field tests costing several million dollars would be required to prove the suitability. The most suitable aquifer is near Seaspray, where several dome structures exist. The aquifer, comprising of coarse sands capped by coal and mudstone, is some 600 metres deep with a hydrostatic pressure of 6.3 MPa. Computer simulation of injection and extraction of air from the aquifer under various combinations of horizontal and vertical wells, permeability and tubing head pressures indicated the largest aquifer structure had the capacity to sustain a 300 MW station. A well field comprising of 24 directionally driven wells with a horizontal exposure to the aquifer would achieve the air flow rates required. Using plant similar to that recently installed at McIntosh Alabama USA, would mean high capital costs compared to standard gas turbine plant. However, a review of modem gas turbines indicated that they could be easily and economically adaptated to CAES duty. Adapting a 120 MW gas turbine would give 344 MW output. A separate air compression plant would be used. Economic evaluations indicate that, for gas prices above $1.95 per GJ, a 344 MW CAES plant is more economic for intermediate/reserve load duty than simple cycle gas turbines.

Jan 1, 1992

By J. F. Curtis

In the synopsis, the author concludes that ?high levels of seismicity do not coincide with high rockburst rates?. Implicit to an appreciation of this statement is the necessity of a common understanding of what is understood by the terms: ?high level of seismicity? and ?high rockburst rates?. With respect to the former term there is no difficulty in that the level of seismicity is traditionally measured in terms of the Richter Scale. The latter term however presents a problem in that the author defines it as a particular sort of seismic event?viz: ?Rockburst? is understood as a seismic event that causes damage to an underground excavation with subsequent injury, loss of material/equipment or production shifts? (p. 322). No scale is given of the amount of: ?excavation damage ?level of injury ?material/equipment loss ?production shifts lost whether separate or cumulative, for a particular seismic event to be classified as a rockburst. A further difficulty arises in that in common usage the words ?rockburst?, ?seismic event? and ?earthquake? are all used to describe the same event.

Jan 1, 1999

By Gordon R. Sima

The contract is concerned with feasibility studies, design and fabrication of a group of prototype hand-held test instruments and machine-mounted test instruments for measurement of electrical shock hazards of mining machines. An instrument for use in open pit mining machine ground wire verification was proposed, developed, built, and tested. This report presents the design and operational theory of the open pit instrument as well as information on the program to improve the original prototype hand-held machine-mounted test instruments.

Jan 1, 1977

By B. H. Clemmons, B. G. Saunders, R. H. Stacy

"INTRODUCTION This investigation was undertaken to determine the response of Birmingham (Alabama) red-iron ore to heavy-medium concentration. Specifically, the work involved a study of the efficiency of the process in separating coarse gangue diluents from the ore and an endeavor to evaluate the potential economic results. The investigative work was not intended, nor is it to be construed, to be adequately exhaustive in scope to enable immediate plant construction. Rather, the primary objective was to determine the grade of ore that could be produced by heavy-medium treatment and the resulting indicative or tentative benefits to be derived from such treatment. The latter, in turn, would determine the merits of the more exhaustive study that would be required for an ultimate decision on the heavy-medium treatment of the ores.The problem of avoiding excessive contamination of red-iron ores by shale and/or ferruginous sandstone has been before the operators of the iron mining industry of the Birmingham, Alabama, district for many years. Within the last two decades, increased mechanization of mining methods has increased this contamination to a considerable degree. In fact, general utilization of scraper loading and other mechanical methods of mining, in conjunction with small increases in the natural insoluble content of the ores, in some cases has actually resulted in the production of ""acid"" or excessively insoluble ore, where ""basic"" or excessively lime ores were produced formerly.The contaminating materials are derived largely from roof spells and natural parting seams in the ore, a condition that to some extent has been aggravated by the irregularity of the ore beds. The latter have been subjected to both primary and secondary folding in many places. Considerable faulting has taken place, also. In many localities these conditions render virtually impossible complete avoidance of ore contamination from the over and underlying sandstones and shales. However, in a few localities, where the ore beds are less disturbed and shale partings are absent, mining can and is being accomplished with relatively little dilution."

May 1, 1948

7253. Arkhangelsky, A. D. Geological Results of the General Magnetometric and Gravimetric Surveys of the U.S.S.R. (in Russian). Internat. Geol. Cong., Rep. of the 17th Sess., Moscow-Leningrad, 1937, vol. 1, Moscow, 1939, pp. 241-250. Geophysical methods have been used in the U.S.S.R. to study geological problems. Such is the case of the general magnetometric and gravimetric surveys made jointly by the Main Physical Observatory, Main Office of Geodesy and Cartography, Institute of Terrestrial Magnetism, and Main Office of Geophysical Prospecting. Some institutions supplied the data, others processed them. Geological interpretation was made by the author. (1) Regional magnetic anomalies in the plains of the U.S.S.R. are traceable to the folded substratum overlain by sedimentary rocks; these anomalies promise to yield data characterizing the substratum in respect to strike and depth. Anomalies in European U.S.S.R. suggest that the pre-Cambrian -substratum of the East European plateau consists of elements of different ages. In the most ancient of them, the main strike of the folding is almost latitudinal; in the younger ones, the folding is oriented in the meridian. (2) The Faye and Bouguer gravity anomalies are caused primarily by differences in the density of rocks composing the upper crust and by unknown processes producing changes of density at depth; these processes are not connected with isosiatic movements. The anomalies in the European and adjoining Asiatic U.S.S.R. promise to indicate the volume of the pre-Cambrian massif of the east-European plateau and to clarify the interrelations between the Ural, Tian-Shan, and Donetz Basin folding systems, as well as between the Dnieper-Donetz depression and the mid-European depression. - V. S.

Jan 1, 1944