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By Oliver Bololes

UNDER the able leadership of Samuel H. Dolbear, the Committee on Nonmetallic Minerals furnished a program of sixteen papers comprising three sessions. An outstanding accomplishment in technology presented at the first session by Benjamin L. Miller and C. H. Breerwood is the application of flotation to the purification of limestone used in cement manufacture. In place of selective quarrying to provide high-grade raw material, the quarry-run stone is pulverized and treated in froth flotation cells for removal of free silica and mica. Some advantages are cheaper quarrying, more complete utilization of quarry rock, avoidance of purchasing high calcium stone, lower fuel cost and improvement in the finished cement. Paul M. Tyler presented the general subject of milling methods as applied to nonmetal lies. He pointed out the importance of some of the more recent refinements in ore dressing, and urged the need of a wider appreciation of their possibilities. The gypsum industry of Canada was described by L. H. Cole. Crystal growth during the setting process was illustrated by moving pictures. The Coastal Plain and interior salt

Jan 1, 1935

By AIME AIME

AWIDE variety of subjects was discussed at the Wednesday sessions on Non-metallic Minerals. W. M. Weigel as chairman, presided at the morning session, and W. M. Myers, vice-chairman, in the afternoon. In the morning session a paper by W. N. Logan on "Mineral Wool Resources of Indiana" was read by H. H. Hughes. Mr. Logan explained that as Indiana is the principal source of mineral wool, the paper might well he entitled "Mineral Wool Resources of the United States."

Jan 1, 1932

By J. Tavares

It is no mystery why the mining industry has such lofty safety standards. In dealing with Mother Nature and gravity, the combination of the two can create significant hazards from high wall and tunnel collapses to huge landslides. The loss of production from a major disruption could be enormous. The price tag on the loss of human life is immeasurable. The evolution of geotechnical instruments and software has been ongoing for years. But the biggest innovations have occurred during the era of cell modems, internet, and wireless networks, allowing for real time data and alarms to be delivered globally anywhere and anytime to one?s computer, laptop and smartphone. Yet in some ways you can thank the urban construction projects for developing much of the technology in use by today?s mines. Due to the density of population and the billions in dollars of structures and infrastructure in cities throughout the US and the world, urban projects have faced intense scrutiny for years. Out of this scrutiny was born the necessity of real time automated monitoring of instrumentation and sensors, a defence against catastrophic failures, and real time early warning systems through alarms that can and do saves lives. It is also possible to identify areas of concern with subsequent remediation prior to failure.

Feb 23, 2014

By John P. McDonnell

Coal mine bounces and bursts are major problems facing U.S. mine operators. Bounces and bursts have the potential to inflict severe injury on mining personnel, damage equipment, and cause mine closures. High- stress conditions, at or near the working face, are the common denominator in the burst problem, If mine operators can locate high-stress and potentially burst-prone zones, they can then use stress-relief methods to control the burst condition. One method of locating the high-stress zone is the probe-hole-drilling or drilling-yield method. Probe-hole drilling is used frequently in Europe, the U.S.S.R., and Japan as a means for locating potential burst zones. Consequently, the Bureau of Nines performed tests in the laboratory and in a deep, burst-prone western mine to analyze probe-hole drilling. The in-mine method, very simply, involves drilling a hole into the coal seam and measuring the volume of cuttings obtained. A certain volume of cuttings can be expected from a certain diameter and length drill hole. A significant increase in the volume of cuttings means the zone around that particular hole is highly stressed. In-mine use of the drilling yield method has shown it to be a useful tool for locating highly stressed and potential burst zones. Results from laboratory testing confirm that high stress applied tri-axially to a cube specimen will cause a significant increase in the volume of cuttings from a small-diameter drill hole in the specimen.

Jan 1, 1988

By Eric Bain Wasmund, Lance Christodoulou, Julio Jairo Carmona Franco, María Fernanda Castillo, Jose Concha

"A number of technologies are in practice for selectively removing coarse gold from conventional grinding circuits. These circuits are often designed so that the grinding mill output is size classified, with large (or high density) particles being removed before the tails are returned to the mill. Because of the high relative SG of gold, and the fact that some forms of gold such as free gold do not break apart during conventional grinding, coarse gold can accumulate in the circulating load, and eventually be lost.Eriez has developed a flotation cell that uses fluidized water to enhance flotation of coarse particles. More than 40 units have been sold in industrial minerals, and we are now exploring applications for the HydroFloat® in the gold industry.Mineros S.A currently produces approximately 120,000 oz of gold per year by gravity concentrating alluvial gold ore with a mean particle size of 330 microns, followed by further concentration using a Falcon separator. A 400 mm diameter pilot-scale HydroFloat® was added to the tails of the Falcon to test whether additional gold could be captured. Enrichments of 50-600 times and recoveries normally in excess of 95% were achieved. This allowed direct smelting of the gold concentrate. Metallurgical results and operating parameters such as water addition and power will be discussed during the presentation.This result opens the possibility that the HydroFloat® could be used directly in the grinding circuit, for removing coarse gold in the circulating load. This work also shows the possibility that the HydroFloat® can produce a throwaway tail, which will reduce the size of the circulating load stream and the grinding requirements of the circuit."

Jan 1, 2015

By Jeffrey M. Listak

This U.S. Bureau of Mines report describes the implications of in-mine ground control on the automated or remotely controlled operation of longwall mining equipment, Perhaps the greatest challenge to longwall automation researchers is the development of systems that will continuously function in the complex and unpredictable underground environment. The high degree of environmental variability, together with conditions brought about by the extraction process, makes complete automation of longwall mining a difficult task. The intellectual thought processes and split-second decision making required to avert disasters are lost when workers are removed from the face. As many mine operators can attest, minor problems, left unresolved, can eventually accumulate and lead to catastrophic consequences. The automation process will have to assess and manage various routine problems that are otherwise resolved through worker observation and experience.

Jan 1, 1990

By Charles E. Locke

CONTINUED expansion of gold mining in 1935 led to further developments in treatment methods. In base metals and non-metallics progress is also noted, coincident with greater activity. Statistics are not available yet for 1935 but the trend is shown by 1934 when nonferrous ore mined in the United States was 35,840,737 tons, or 45 per cent more than in 1933. The amount concentrated was 27,167,530 tons or 75.80 per cent of the ore mined, and flotation was used in whole or part on over 96 per cent of the ore subjected to concentration. In the crushing field a new model of the Fahrenwald crusher is promised soon. The Symons fine-reduction cone crusher and Traylor secondary crusher continue to gain as intermediate crushers. A new book entitled "Crushers for Stone and Ore" by William T. W. Miller appeared. The Hadsel mill has been improved still further and a number of installations are in satisfactory operation showing economical power consumption and low wear. An attempt in a

Jan 1, 1936

By W. A. Lang

COAL of sub-bituminous rank underlies much of the plains area of Alberta. This coal is geo-logically young, and occurs in Belly River and Edmonton strata of Up-per Cretaceous age. Generally, the seams are flat-lying, but in some areas they may dip as much as 5 degrees. The overburden, composed mainly of glacial clays and sand-stones, may vary in depth from a few feet to several thousand feet. Recovery of the coal has 'been by drift, slope, and shaft underground mines, and by open-pit stripping operations. Production has been obtained from a large number of mines, most of which have been relatively small and with preparation equipment limited to a loading tipple with screening facilities, and a picking belt where high-ash materials can be removed from the larger sizes. The coal has been sold for domestic and industrial space-heating, for production of process steam, and for power generation. In re-cent years competition from natural gas, propane, and oil has seriously interfered with the production and marketing of sub-bituminous coal, especially with the disposal of the smaller sizes at a realistic price.

Jan 1, 1958

By Andrej Šubelj

The paper tries to determine all which are interested or involved in collecting, evaluating, processing and distributing data on mineral resources, either "economic" or "uneconomic" and for what purposes. It shortly describes some of the most known classification systems, CMMI and UNFC, and their features, and discusses their advantages and weaknesses. Author also tries to define all the properties, a system should have to be declared as "World Code". Perhaps the ,integration of both systems would best accomplish the task and leave the “interest groups" the freedom to use only those parts of the system, they are interested in.

Jan 1, 2002

By N. S. Dalal, X. Shi, V. Vallyathan

"Electron spin resonance (ESRJ spectrum of the hydroxyl (· OH) radical spin adduct with .the spin trap 5,5-dimethyl-1-pyrrolintt-N-oxide has been obtained in suspensions of freshly ground quartz particles. The concentration of the spin adduct (and hence of the • OH radicals) increases with the amount of grinding. The dust's potential for the generation of the· OH radicals is maximum when fresh (i.e., immediately after grinding) and decreases to 50% in about a day on storage in air. Studies involving metal chelates .indicate that the • OH radical formation involves mainly the silica surface and H20 rather than the Fenton reaction. The results suggest that hydroxyl radical reaction(s) could be important in the lipid peroxidation and fibrogenicity by quartz dust, particularly .in acute silicosis. INTRODUCTIONIn this paper we report on our electron spin resonance (ESR) detection of the formation of hydroxyl (·OH) radicals in aqueous suspensions of freshly crushed quartz particles. This work was undertaken with a view to find possible clues to the role of free radicals in the pathogenesis of quartz-induced fibrogenicity, commonly known as silicosis. We noted that while silicosis is one of the major health hazards in coal and mineral industries, the mechanism by which the quartz particles exert their toxic action on cells and the process(es) by which these actions progress to fibrogenesis are still poorly ·understood (Reiser and Last, 1979; Singh and .Rahman, 1987). It is generally thought, nevertheless, that the action of quartz particles on the biological membranes is the starting point of the silicotic process (Parazzi et - al., 1968). A possible clue to the mechanism of the membrane damage by quartz particles, in terms of the role of oxygenated free radicals, is suggested by the following observations. A suspension of quartz particles in contact with alveolar macrophages has been reported (Gabor et al., 1975; Koike et al., 1982) to initiate an enhancement of lipid peroxidation, defined broadly as the oxidative deterioration of polyunsaturated components of lipids. Hydroxyl (· OH) radicals are known to be capable of peroxidation by abstracting hydrogen atoms from cell-membrane lipids (Halliwell and Gutteridge, 1985) and of initiating lipid peroxidation in lysosomal membranes. (Fong et al., 1973). Arong other lines, it is known that exposure of cell membranes, fatty acids, and unsaturated food oils to ionizing radiation, which generates· OH radicals, causes rapid peroxidation (Halliwell and Gutteridge, 1985). Thus • OH radicals (and also other oxygenated species such as Oi, 10 2, and H20 2) might be expected to play a role in the toxicity of quartz. Earlier studies of the aqueous chemistry of quartz suspensions have reported detection of H2O 2 (Kalbanev et al., 1980), implicating the formation of ·OH radicals as transient species. However, we are not aware of any report of the detection of • OH radicals in quartz reactions, and thus the present study was undertaken. Since it-is known that, because of their high reactivity (hence short lifetime) in aqueous media, the • OH radicals cannot be detected via ESR directly (Finkelstein et al., 1980; Buettner, 1982) we have used .ESR combined with the spin-trap methodology (Finkelstein et al., 1980) for studying the· OH formation. The results show that· OH radicals are indeed formed in aqueous suspensions of freshly ground quartz; thus pointing to ·a possible new clue to the cytotoxicity of freshly formed quartz particles and thereby to silica fibrogenicity."

Jan 1, 1988

By Ernest Bohnet

Each mining operation is unique in some aspect ownership; ore body location, size, geometry, grade, mineralogy, hydrology, or geotechnical parameters; or constraints such as environmental regulations. However, all mining operations are alike in one aspect; the prime objective of any mining project is to maximize the return on the investment. This is the golden rule, or in the language of mining, the investor?s law of conservation. A mineral resource, by definition, does not become a minable reserve unless the mineral or minerals can be extracted economically (and legally). The three preceding sections have covered the various types of surface mining options. The choice of the most economic method is dictated primarily by the type of de-posit to be mined, the mining rate, and the physical characteristics of the deposit.

Jan 1, 2008

By P. Halsall

Smelters of medium or low grade tin concentrates must recover a high proportion of tin from iron-bearing slags or concentrates; the volatility of tin sulphide makes possible the production of iron-free tin fume. Laboratory work defined conditions which would promote the sulphidisation of tin slags and concentrates melted with them, to result in tin recovery as fume, and a residue of less than 0.5% Sn content, which could be controlled to vary with the value of tin. Subsequently pilot-plant work on 6-tonne and 15-tonne scale led to a commercial plant of 45 tonne. capacity (1962), for melting and fuming primary and secondary low-grade tin materials by submerged combustion. Some factors contributing to the rate of Working expressed in terms of the 'half-life and the amount of work done, the 'half-life-tonne' are studied, leading to the design and operation (1972) of the 100-tonne water-jacketed unit, presently in use, treating a wide range of slags and low tin-content ores and residues.

Jan 1, 1983

By Yasushi Arai

"Among Tokyo Metro’s approximately 200km of subway lines, the Tozai Line that connects Chiba Prefecture and mid-Tokyo experiences congestion of up to 199% at worst and relief of this has become urgent. Therefore, as it is imperative to increase the number of trains operating in the exceptionally congested area from mid-Tokyo going east, a large-scale renovation work is planned between Iidabashi Station and Kudanshita Station that will facilitate turn-back via 3 tracks. While ensuring the safe and stable operation responsible for about 1.35 million passengers daily, this highly difficult work of inner wall demolition and reinforcement of the side walls and floor slabs will only be implemented for 3 hours during late night. This paper discusses large-scale plans to improve turn-back facilities, and the methods of construction therein as an example of operational improvement of a subway network. 1) INTRODUCTION The Tokyo Metro Tozai Line (“Tozai Line”) opened over the entire 30.8 km distance from Nakano to Nishi-funabashi on March 29, 1969. It has the longest operating length of the nine Tokyo Metro lines, and was the first subway line to extend past the borders of the Tokyo Metropolis. Through train services with two other railway companies are available from the Tozai Line. Tozai Line trains join the Sobu Line of the East Japan Railway Company (“JR East”) and the Toyo Rapid Railway Line of Toyo Rapid Railway (“TR”) from Nishi-funabashi Station, and the JR Chuo Line from Nakano Station. The line is structurally distinctive in that 51% of it was built using the open-cut method, 43% of it is elevated and the remaining 6% was built when we used the shield method for the first time 1)2)3)."

Jan 1, 2016

By Mayfield P. L J, Honeyands T. A

BHP's two million tonne per annum nominal capacity Hot Briquetted Iron (HBI) plant at Port Hedland in the Pilbara region of Western Australia is based on FINMET¦¦ direct reduction technology. The FINMET¦¦ process produces direct reduced iron (DRI) by reacting fine iron ore with reformed natural gas in a series of fluid bed reactors and then hot briquetting this DRI into dense, high quality iron briquettes. The Port Hedland HBI project represents a major investment in the chemical processing of Australian minerals to higher value products prior to export to Asian markets. This paper describes the FINMET" process and technical aspects of the high-quality HBI product, and provides an update of the current status of the project.

Jan 1, 1999

By E. S. Machlin, C. W. Chen

THIS investigation is concerned with the origin of the intercrystalline voids and cracks formed in metals and alloys subjected to stress at elevated temperature. There have been many suggestions in the recent literature relating to this problem. Greenwood' suggested that the voids may be produced by vacancy condensation. Zener has stated that shear-stress relaxation across grain boundaries could initiate high tensile stresses at the regions blocking grain boundary slip and thereby cause the formation of cracks. Chang and Grant3 have described the formation of cracks at grain boundary triple points and have experimentally verified Zener's mechanism for the grain boundary regions in the vicinity of a triple point. Subsequent to the completion of this investigation, Gifkins4 developed a model which made use of Stroh's5 mechanism of fracturing to produce sub-microscopic fractures that subsequently grow by grain boundary slip. Chen and Machlin,6 in answer to Gifkins, described a model deduced from the present investigation, in which grain boundary slip provides both the stress to fracture at grain boundary jogs and the deformation required to separate fractured jog surfaces. The possibility of gas condensation to form intercrystalline voids and cracks is eliminated as a basic mechanism because such voids and cracks are developed in vacuum melted material containing minute amounts, if any, of gaseous impurities. In a theoretical evaluation of this problem, Machlin7 concluded that void nucleation by vacancy condensation during creep-rupture is improbable but that vacancy condensation on supercritical sized voids to produce growth is probable. This investigation was begun to evaluate the suggested mechanisms for intercrystalline fracture. In particular, in order to correlate vacancy supersaturation ratios produced in creep with those determined by Bal-luffi and Seigle8 as critical for , the nucleation of voids, specimens were obtained from the same heat of brass as used by the latter authors, through the courtesy of Dr. Seigle. The experiments conducted in this investigation fall into the following categories: 1) Brass—observation of voids produced under a variety of conditions, including creep under compression, to evaluate the mechanisms of void nucleation and growth. 2) Bicrystal experiments to check the mechanism of void nucleation deduced in this investigation. 3) Morphology of intercrystalline voids produced in a variety of metals. Each set of experiments will be described and discussed separately. Experimental Techniques A special creep-rupture test rack was constructed which made it possible to apply the stress to the specimen in a controlled atmosphere of inert gas, reducing gas, or vacuum. All the creep-rupture tests on a-brass (30 pct Zn) were conducted in nitrogen under a pressure slightly above atmospheric. Either dead weight loading or constant elongation rate loading could be applied with the load measured by means of a strain gage dynamometer. In order to obtain a coarse-grained crystal structure stable at

Jan 1, 1958

By Leonard Obert

THE CRACKING AND POPPING of rock, often heard by men working underground, for years has been interpreted as a warning of danger and unstable ground. However, not until 1939 was it discovered that rock under stress generates subaudible and sometimes audible seismic disturbances (referred to as "micro-seismims" 4), which can be detected with the use of a suitable seismic apparatus. Since that date laboratory and field investigations have been in progress to ascertain to what extent this phenomenon can be utilized to detect, localize, and determine the magnitude of areas of instability in and around mine openings and to predict if and when failure will occur. These investigations have included a determination of the types of problems to which the method is applicable and the effect of rock type, geological defects, such as joints, fractures, faults, and other uncontrollable factors, on the reliability of results. Six reports have been prepared covering the investigations conducted between 1940 and 1952 (4-9). 5 These reports describe some of the characteristics of micro-seismims, as determined from both laboratory and field tests; the equipment used to pick up and record micro-seismims; the general test procedure and method of analyzing results; and applications of the method to specific mining problems.

Jan 1, 1957

By Thomas. L. O.

Apart from a few sketches and incomplete maps, mainly topographical, and one or two detailed maps of placer-creeks, there is little information on the topography and geology of most of the country adjacent to the sections of the Alaska Highway in the Liard River area, particularly that part east of Kechika river. In 1943, the Geological Survey of Canada made a recon-naissance from Fort Nelson clown the river of that name to the Liard, thence up the latter to Hell Gate, and also up Beaver river for a distance of fifty miles. The whole of the area covered was found to be underlain by sedimentary rocks, not a single igneous dyke being seen. The British Columbia Department of Mines began reconnaissances near the highway both in and north of the drainage basin of Prophet and Muskwa rivers with a view to finding structures favourable for the accumulation of oil. In Liard River valley near the mouth of Smith river and at intervals from there clown to Devil' s Portage occur warm springs whose character and origin are not definitely' known, since they have not been investigated (21, p. 38A). Similar springs are said to occur at several localities over a broad belt extending from Muskwa river across the Liard to the Nahanni River country (26, p. 11). On Liard river below the mouth of Dease river, stratified sands, gravels, and clays of Pleistocene (?) age are constantly met with and in one or two places are underlain by sandy clays. The distribution of the latter, however, is very limited in the section cut by the river west of the Rocky mountains. The only range of these mountains that reaches the Liard is the high limestone ridge which approaches the mouth of Vents river from the southeast and then almost vanishes a few miles to the northwest of it (27, pp. 43-45). In general, the ranges of the Rockies in the area under consideration have been but little explored, but they are undoubtedly very largely sedimentary and, with the exception of some volcanics and intrusives on their western flanks, are probably almost entirely so. Unlike the high, deeply incised ranges in southern British Columbia, they dwindle in elevation north of Terminus mountain to low-wooded ridges separated by wide swampy valleys, and practically lose their identity between it and the Liard. The foothills, which, along the Liard, have a width of 38 miles (from near the mouth of Trout river to Hell Gate) are composed of a great series of alternating shales and sandstones, with some limestones, all folded closely together, which resemble those found in the foothills farther south (27, pp. 50, 19-20).

Jan 1, 1944

By Alexander Burns, David Dreisinger

The kinetics of the oxidation of uranium(IV) by oxygen gas in aqueous systems is dependent on acid concentration, oxygen partial pressure, and temperature. In order to better understand the relationship between these variables and the speed of oxidation, a series of experiments have been conducted where each parameter has been varied in turn. Data were collected continuously using UVVis spectroscopy, allowing for a detailed examination of the reaction rate over the course of each experiment. The data fit an overall apparent rate law that is 1.5order in uranium(IV), -2order in H+, first order in oxygen, and unaffected by uranium(VI). This relationship does not appear to hold for solutions with <0.2 mol/L initial acid, where a different kinetic mechanism appears to be dominant.

Jan 1, 2014

By N Tyson

Throughout Australia and the world, there have been in recent years a number of incidents involving the reaction of ammonium nitrate based explosives with ground containing certain types of sulphides. This paper presents a comprehensive strategy designed to identify, assess and mitigate the risks involved with blasting in areas of reactive ground. Undertaking blasting in reactive or potentially reactive ground involves a degree of risk, the level of which is dependent upon the controls in place for specific sites; this in turn depends upon the degree of sound reasoning and judgement behind the implementation of these controls. Implementation of controls to minimise the risk of incidents also involves a measurable increase in production and blasting costs. To achieve a balanced solution to this matter, decision-makers need to understand how the risks eventuate, how they should be evaluated, and how control measures reduce the risk. Also required is an understanding of how the problem affects the economics of the operation, and the magnitude of this effect. It is the aim of this paper to provide a structured approach to gaining this knowledge, so that mine management, the workforce and explosive suppliers may jointly develop more effective economic and safe blasting systems for potentially reactive ground. Using a combination of fault/event tree risk assessment and semi-quantitative analysis, a structured approach to dealing with the issue will be illustrated.

Jan 1, 2001

By R. S. Kasper

This paper reviews the procedure used to quantify the conveyor frictional resistance on a 3.9 km (2.4 mile) long overland conveyor belt. Field torque measurements of the three drives were used to help fine tune a computer simulation of the conveyor. This enabled the prediction of the effect on various conveyor components that cold temperatures will have on increasing the throughput tonnage.

Jan 1, 1995