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By J. N. Adamson

The Alcan Smelter project at Lynemouth on the Northumbrian coast draws cooling water for the power station through shafts and tunnels from the North Sea. The sea at this part of the coast is frequently very rough and even in calm weather the coastal currents are strong. The adjacent coal mine makes use of these currents to disperse colliery waste and discharges into the sea some thirty thousand tons each week. In consequence the sea bed is continuously shifting and the sea is black and turbid. Construction of sea shafts under these conditions presents difficulties as drilling from a floating vessel is hazardous and sea bed activity of divers is greatly hindered by the entire absence of visibility. After considering several alternatives a method of construction was agreed with the Consultants in which the drilling and also the lining of the shaft would be completed in sequence from an eight legged work barge (GEM 126). Each shaft would be drilled to full depth and a steel cylinder, with its ends closed temporarily, would be lowered into the hole and grouted into the formation to form a full-length permanent lining. The bell mouth for each shaft would be constructed in advance to form part of the cylindrical casing. On interception of the shaft by its appropriate tunnel the lower end of the cylindrical casing would be cut away and the internal walling of the shaft installed from below. After completion of construction the shafts and tunnels would be flooded and the bell mouth sealing covers removed by divers.

Jan 1, 1997

By Thomas M. Drown

THE means relied on to attain uniformity in Bessemer steel may be enumerated as follows I. The appearance of the flame. II. The appearance of the slag. III. The spectrum of the flame. IV. Examination of the steel itself. At present, I wish briefly to bring forward a few considerations with reference to the last two mentioned, namely, the conditions favoring the employment of the spectroscope and examination of the steel. From the amount of careful investigation which has been devoted to the examination of the Bessemer flame by the spectroscope, both on the part of scientists and practical metallurgists, one might reasonably expect some results definite and satisfactory in their nature, first, as regards the nature of the flame, and second, as to the practical value of the spectroscope as a guide in conducting the process. We find, in fact, however, that uncertainty and confusion still exist. In Germany, where this subject has received the greatest attention, it is now very generally conceded that manganese is the cause of the well-known groups of dark bands that characterize the Bessemer spectrum. Nor is it easy to see how we can avoid accepting this conclusion, when Wedding and Von Lichtenfels have produced the manganese spectrum and found it to correspond closely with that shown by the Bessemer flame. But it is evident, on a moment's reflection, as Roscoe has recently brought forward, that manganese cannot be the only cause of the Bessemer spectrum, for we notice the characteristic bands quite as

Jan 1, 1873

By Richard Moldenke

ONE of the gravest problems of the iron foundry today is the accumulation of sulfur in commercial scrap and its effect on the castings made therewith. The ordinary jobbing castings today show a sulfur content of 0.18 per cent., and occasionally as high as 0.22 per cent. The product of the foundry during the war is undoubtedly .to blame for this rapid increase and conditions will become worse as the millions of tons of gray-iron castings of the war period return to the foundry in the form of commercial scrap. In the ordinary cupola remelting of pig and scrap, at least 0.02 per cent. sulfur is taken up; often double that amount. The high cost and difficulty of obtaining pig iron during the war period compelled the use of considerable scrap in the mixtures; frequently charges containing. 90. per cent. of bought scrap were melted. Naturally the sulfur content of the castings increased. Until the advent of the basic-hearth electric furnace, the only method of holding the sulfur within reasonable limits was to use high percentages of pig in the foundry mixtures. Pig iron seldom contains over 0.05 per cent. sulfur, if well made. With pig iron forming 60 percent. of the .charge and the gates, runners, rejections, and bought scrap the other 40 per cent., the sulfur content of the castings can easily be held down to 0.10 per cent. Pig iron, however, costs more than scrap even when melting loss differences are considered, hence as small a percentage as possible will be used.

Jan 2, 1921

Australian coal mines have spent considerable capital on dragline improvements over the last two years. This has included ~$30 M on UDD conversions, >$20 M on new buckets, boom upgrades, electrical upgrades, etc. This is a natural part of the response of mining companies to technology and replacement programs. Capital expenditure is a normal part of the ongoing success of most companies. There is however, a tendency for some people to rely on the capital alone to provide the ongoing improvements in equipment productivity. Implementing new technology through capital expenditure is only part of the equation in continuous improvement. For 80 - 90 per cent of the year, the operator controls the productivity achieved by the dragline. Variation between operators is huge. The average standard deviation in productivity is 12 per cent and maintenance impact is over 40 per cent. Robbins 2003, states: Contrary to what we were taught in grade school, we werenÆt all created equal. Most of us are to the left of the median on some normally distributed ability curve. Further, he states: The issue is knowing how people differ in abilities and using that knowledge to increase the likelihood that an employee will perform his or her job well. There are two options for reducing variability between operators; improving operator ability and getting the machine to take over what the operator is doing (automation). Dragline automation will be discussed, however, this paper will focus more on the æhuman factorÆ and how to establish a dragline with minimum variability between operators.

Jan 1, 2005

This paper describes the new legislative regime that will apply to the regulation of the minerals industry in New Zealand. The reform of New ZealandÆs minerals legislation was initiated in January 1988 when the Minister for the Environment, Rt Hon Geoffrey Palmer, announced the Governments intention to review all the major laws governing New ZealandÆs resources. The Resource Management Bill is scheduled for introduction to the House in December 1989 and its date of enactment is scheduled for June 1990. With some matters still to be determined (at the time of writing), this paper cannot be a definitive review and description of the new legislation, it is instead an attempt to outline the major features of the Bill, to date, that are seen as important to the mining industry.

Jan 1, 1990

By Randhir Sehgal

Heavy media processes have been used for cleaning +28 mesh coals for a number of years, Two applications, i.e., the vessels and the cyclones are widely used in the U. S. for this purpose. The basic reason for the popularity of these systems is their extremely high efficiencies for particle sizes above 28 mesh, However, application of heavy media technology to fine coals below 28 mesh, has been limited due to the following reasons: o Inability to make size separations effectively at sizes below 28 mesh o Necessity of feeding large quantitites of magnetite to the separators o Difficulty of recovering magnetite in the presence of large quantities of coal o High levels of coal contamination in the recovered media, leading to high circulating loads and ineffective control of media gravity

Jan 1, 1981

By S. Nafisi

Permanent mould casting may be regarded as a near net shape manufacturing process where simple to very complex shaped engineering components are fabricated with high degree of precision in a metallic mould, In this group, High Pressure Die Casting (HPDC), have attracted more attention because of its production rate, where both liquid and semisolid metals (SSM) can be cast with high degree of precision and versatility. The SEED process, Swirled Enthalpy Equilibration Device, the new process for semi solid metals slurry production route, consists of two steps: The initial step involves extracting specified amount of heat from the molten metal to generate liquid-solid slurry, i.e, mushy structure, followed by drainage of remaining liquid to produce a compact free standing feedstock for rheocasting operation. In this paper, microstructural evolution during the process and some initial casting results of automotive components an also reported.

Jan 1, 2005

By M. J. Coolbaugh

Mining of potash more than 3000 ft beneath the water-bearing sediments in Saskatchewan presented the unique challenge of designing stable mine workings and assuring protection from overhead water in a material that was believed to flow plastically, but whose behavior as a plastic material was not sufficiently known. Under the stress conditions ordinarily encountered in mining most rocks behave as elastic materials; that is, they compress slightly under pressure, and rebound when the pressure is released. Salt and potash, however, are different. Even under the relatively low pressures encountered at shallow depths, these materials become slightly plastic and yield to stress by flowing.* The plastic properties become more pronounced at greater depth and pressure, and the question arises as to whether or not the plastic flow will be rapid enough and exert enough pressure to destroy underground structures or interrupt the mining process.

Jan 5, 1967

By W. W. Hartley

Following a Major underground coal mine incident there followed a review of the role of mines rescue ? the Queensland Mines Rescue Brigade. It wasn?t until 2002 that the real change started to happen. The issue of geographical distance was addressed by mines rescue sub stations being located on the mines sites with parent rescue stations in a central location. The funding was by means of a levy on the mining industry with legislative standards and performance included. The previous Rescue Brigades were not well organised (central districts) and the application of recognised quality management practices within local management was lacking. The structure was based on other nations models and miners managing miners was an issue for the organisation. The reform was some what painful and the QMRS organisation will still evolve with continuous improvement. Queensland has the National Champion mines rescue team for the eighth year. QMRS is participating at the level in the industry of influencing emergency systems and training senior mine management in ?Emergency Mine Management? coaching the industry in emergency response systems. We have come a long way. We have had some success and there is always the challenge of setting the standards, those we should aspire to and the courage to influence the industry to higher goals of a safer future.

Jan 1, 2010

By David Weiss

There is significant interest in magnesium alloy castings because of their low density and high strength-to-weight ratio. Lightweight, structural materials are in demand for aerospace components, hand tools, electronics enclosures and have found increased use in automobiles. Increased use of magnesium will depend on the resolution of a number of materials issues and development of more robust and economical casting processes. Most magnesium components are produced via high-pressure die-casting. High levels of porosity generally prevent die-castings from being used for structural applications. Structural castings are usually produced using sand casting, a relatively expensive casting process. Some work has been done on development of lower cost structural casting processes, such as lost foam casting, permanent mold casting or low-pressure casting. New programs are also emphasizing improvements to the die casting process. Research and cost reduction needs are discussed with respect to current programs and future components.

Jan 1, 2006

By Geo. A. Brown

This paper was written from conditions existing in the Cumberland Mines of The Union Pacific Coal Co., with my impressions and cause of same. These mines are located on a branch line of the 0. S. L. R. R., about sixteen miles south of Kemmerer, Wyoming. The mines are the property of The Union Pacific Coal Company with headquarters at Rock Springs, Wyo. There are two mines, No. 1 and No. 2, located about two miles apart in a seam of coal averaging about 16 feet thick which is split with a parting of rock from 4 feet to G feet from the bottom, averaging from 4 inches to 5 feet thick, mostly of soft fire clay, with an average pitch of 21 degrees to the west. The lower coal below the fire clay band being of a soft nature, much softer than the coal above it. The cover or roof next to the coal is of a massive sandstone formation from 4 feet to 60 feet thick while the floor of the seam is of a soft fire clay as far down as has been prospected. These mines are also of a dry and dusty nature, they generate lots of fire damp and are subject to fires from numerous causes. These mines were opened up in 1900 with five openings each, Main Slope, North and South Manways and North and South Aircourses driven parallel directly on the pitch of the seam which is fairly regular, entries being turned North and South at right angles off the slope about 300 feet apart. The entries were driven double 10 feet wide with chain pillars from 20 feet to 30 feet thick. The main entries are used for haulage and main intake, back entries for return aircourses. Rooms are turned on 50-foot centers and 20 feet wide, directly on the pitch Galvanized sheet iron chutes are used in the rooms. The slopes were driven down in No. 1 mine about 4,000 feet, in No. 2 mine about 5,000 feet where the cover would be about 1,400 feet in No. 1 mine and about 1,700 feet in No. 2 mine approximately. When a point about 2,000 feet on the slope had been reached with cover, 600 or 700 feet squeezing became noticeable on the entries and room pillars with slight bumps which extended clear to the upper entries of the mines and continued to get worse as the mines got deeper and with more cover as no pillars had been removed at this time. It should be stated here that faulty ground was found on the south side of No. 2 mine and on the north side of No. 1 mine, in some places looking like a fault of a down throw, some places like a want and other places like an erosion. The latter theory seems to be correct from prospecting and drilling. The mining of entries and rooms became more difficult with more squeeze and bumps of increased pressure which closed entries and aircourses and finally caused the lower workings of the mine to be abandoned. It was then decided to open up the entries from the 6th up, or approximately half way up the slope. The opening of these entries was started with the intention of extracting pillar coal but considerable danger was met with for the entries .were squeezed tight and when they were disturbed, bumps and squeeze conditions had to be contended with, also gas and fires due to the continued grind on the pillars due to overhead pressure bringing on friction which caused innumerable fires to start in the bottom coal. Bumps being so extensive at times as to close up aircourses for 500 or 600 feet, also discharge timber, coal and rock from the rib of slope and entries for hundreds of feet, dislodging tracks and throwing mine cars around just as if an explosion had taken place, filling places with gas and throwing dust into the atmosphere so that you could cut it with a knife. It became necessary to discontinue the use of black powder and naked lights entirely as a safety precaution. Permissible Powder Monobel No. 5 and Wico Electric Safety Lamps were installed. All coal was shot off the solid whenever it was necessary to shoot. ' In opening up these entries it was found that practically all of the weight was centered on room pillars up to the first crosscut chain pillars and barrier pillars between top of rooms of entry below and the one above which averaged 30 feet thick and in all practically 120 feet of ground. The rooms were mostly open from the first crosscut up to the face which showed that the points mentioned had taken the weight. It was found impossible in some of these entries to drive double entries again as the bumps and squeeze made it impossible to maintain them. This made ventilation quite a problem, small booster fans and flexoid tubing being used for ventilation until one entry could be connected with the one above which has solved most of our ventilation problems so far.

Jan 1, 1924

By N. Loganathan, Tan Boon Tee, Joe O’Carroll, Richard Flanagan

In recent years, tunnelling activities in Singapore have increased considerably with the construction of extensions to the existing sub-surface transport system, a deep tunnel sewerage disposal system, and tunnels for the laying power cables and other utilities. These tunnels are excavated through urban areas, adjacent to high-rise buildings, depressed road structures, beneath other tunnels, and buried services. Earth pressure balance (EPB) tunnel boring machines (TBM) have been used extensively in Singapore with great success. The risk associated with soft ground tunnelling, including tunnelling through Old Alluvium, can be minimized with an understanding of the geology, geotechnical parameters, and the tunnelling-induced behaviour of Old Alluvium (OA The purpose of this paper is to present some design and construction aspects of EPB TBM tunnelling through Old Alluvium.

Jan 1, 2005

By S S. Kahlon

India is a large and growth market for explosives and accessories, which has dramatically changed from complete import dependence to self sufficiency, and now has an exportable surplus. The largest single user is coal mining which is continuing to show a healthy growth with opencast mining becoming increasingly dominant. The explosives industry has kept pace with mining and today all the well renowned explosives technologies of the world are available in the country. While slurry explosives are popular in large diameter, NG based explosives continue to be preferrred in small diameter usage. Emulsion explosives have had a good market response. ANFO usage is limited due to local reasons. As the mine size is increasing, the demand for bulk-on-site explosives is growing. Prices of explosives and accessories are cheap compared to international levels. The user industry is mainly Government owned mines whose profitability is not satisfactory. Explosives industry is over licensed in terms of manufacturing capacity, which is likely to put pressure on the viability of some of the explosives manufacturing units. Scope exists for optimization of blasting parameters through the use of computerized blasting models. The explosives industry is faced with new challenges and opportunities.

Jan 1, 1987

By S. K. Kawatra

A growing concern for pyrometallurgical operations is the generation of airborne particulates. These particulates can be generated by combustion processes, or by materials handling. Regulation of these particles by the EPA has become progressively more stringent, first for particulates finer than 10 micrometers (PM10), which are particles fine enough to be inhaled into the lungs. Then, restrictions were introduced on emissions of particles finer than 2.5 micrometers (PM2.5), which are fine enough to become embedded in lung tissues. The next stage of regulations is likely to be ?nanoparticulates,? particles finer than 100 nanometers, which are in a size range where their very high surface area leads to enhanced reactivity. While all of the health effects due to nanoparticulates have not yet been determined, there have been enough studies to indicate that there is a problem, and restrictions on nanoparticulate emissions are only a matter of time. In this paper, it will be demonstrated that dry handling, comminution, and combustion sources represent a significant concern for both PM and nanoparticulate emissions. In regards to dry handling, the effects of utilizing effective dust suppressants on PM and nanoparticulate emissions will be explored.

Jan 1, 2006

LIEUTENANT MARTIN F. BOWLES Martin F. Bowles, born Apr. 25, 1893, at Bonne Terre, Mo., and graduated from the Neodesha, Kans., High School, had finished all but one month of a four-year course in metallurgical engineering at the Missouri School of Mines, Rolla, Mo., when on May 12, 1917, he entered LIEUTENANT MARTIN F. BOWLES. the first Officers' Training Camp at Fort Riley, Kans. At the close of the training period, he was commissioned a Second Lieutenant and as¬signed to Co. B, 355th Infantry, 89th Division, and stationed at Camp Funston. He left this camp with his company on May 21, 1918, and sailed from an eastern port on June 4, arriving in England on June 15, 1918. After a short stay at a rest camp there, he proceeded to France. On August 14, he wrote that he was with Battalion Headquarters as Scout Officer, 1st Battalion, 355th Infantry, 89th Division. The last letter received from him, dated September 2, was written in his dugout and contained the following: "Here it is 2.45A. M. Sitting in a dugout

Jan 1, 1919

By Hans Neuberger

INTRODUCTION IN our everyday life, visual perception plays perhaps a more important role than any of the other senses with which we are equipped by nature. It is, therefore, quite understandable that the average person associates 'with the term "atmospheric pollution," clouds of dust, palls of smoke or deposits of soot, phenomena which are so familiar to the residents of industrial cities. On the other hand, "air" is usually considered the prototype of the invisible, of the intangible, and any suspensions in the air which do not conform to this concept, are regarded as foreign to the atmosphere and thus as "pollution." According to Webster, the term "pollution" implies uncleanness, impurity, in short, something undesirable. Although the scientist often accepts popular concepts, he is generally inclined to suspect that apparently "obvious" phenomena imply, literally, "more than meets the eye." To show that this suspicion is also justified with regard to atmospheric pollution, is the objective of this discussion. It will be shown that what seems foreign to the air at first sight, is by nature an integral part of it, and that the more important aspects of pollution generally escape attention. THE ATMOSPHERIC CONSTITUENTS We can distinguish two classes of atmospheric constituents: the permanent gases, chiefly nitrogen, oxygen, traces of argon, neon, and others, and the variable constituents which include water in its different states, carbon dioxide, ozone, and various suspensions, either in gaseous, liquid or solid form. These suspensions, known by the collective term "Aerosol,"20 will be considered in detail. DUST There are two general types of aerosols: the first type is represented by the socalled "neutral" particle 3, commonly known as dust and experienced by everyone, as it is the more conspicuous type of suspensions. . It often represents a special problem to the mining engineer, the mechanical engineer, the industrial engineer, and many other professional men. Dust consists of finely divided solids derived from weathering, drilling, handling and preparation of rocks and coal. Dust may also consist of organic or inorganic particles resulting from manufacture of a variety of products such as flour, rubber, lime and steel, from traffic on land be it on the highways, on rails or in city streets, from decomposed vegetation or from volcanic eruptions. Perhaps the most reviled member of this class of suspensions is the soot and fly ashes from coal fires and other combustion processes. The cosmic source of dust, namely the injection of meteoric matter into the atmosphere, is of minor significance because the concentration of particles is exceedingly small despite the relatively large mass of material invades the earth’s atmosphere from space

Jan 1, 1948

By E. A. Haack, L. A. Warren

Microbial biofilms are essentially biologically driven, geochemically reactive interfaces between solid surfaces and aqueous solution. Field investigation of acid rock drainage (ARD) associated biofilms at the Onaping nickel mine (Onaping, ON, Falconbridge Ltd.) characterizing: (1) micro-geochemical gradients (pH and 02) (2) metal fractionation amongst biofilm solid components, and (3) microbial communities; over both seasonal and diel timescales, indicates biofilms are highly metal reactive. Results show that biofilms accumulate metals seasonally within two microbially controlled solid fractions: amorphous hydrous manganese oxide (HMO) biominerals and the organic biofilm matrix. The biofilm geochemical microenvironment, driven largely by microbial activity, dynamically impacts biofilm metal behaviour over diel timescales. These results indicate that microbes can play significant roles in bulk system reactive metal transport. On-going investigation seeks to characterize the microbial players and the microbial-geochemical linkages involved in Mn oxyhydroxide formation and subsequent metal sequestration, with the goal of engineering this microbial activity as a bioremediative approach. This approach will have utility beyond specific application to the Falconbridge Onaping site to ARD mine environments in general, as the likely microbes involved in these processes are typically common across ARD systems.

Jan 1, 2004

By John F. Abel

In Silver Plume, Colo., there is a bachelor miner who offers individualized tours of his mine, The Silver Cloud. It is an interesting tour because he drove the mine himself and the view from the shack up there is spectacular. Beside that, he will probably invite you into his kitchen to sit around the old cook stove and drink coffee. When Andy first started his tour business he put a sign on the main street to advertise the fact. The sign read in part: "Women not welcome, but they will be tolerated at $3.00 a head”- the usual fee is $2.50. The sign lasted about 48 hours. Andy had to take it down because "all the ladies in town got mad at me. Now I take them all for $2.50 right across the board," he says. The mining industry is not only reticent about hiring women but traditionally does not even permit women to enter some mines. It would appear, what with the recent action on an equal-rights-for- women amendment in Congress, that we may be wise to examine the prospect.

Jan 1, 1970

By A. K. Bakshi, K. J. Shoop, Komar S. Kawatra, T. C. Eisele

Slurry rheology can have significant impact on the performance of autogenous grinding circuits. A viscous slurry can act as a cushion and retard impact forces between the media and the ore, which reduces grinding efficiency. On the other hand, a dilute slurry will not be viscous enough to hold slurry in the impact zone of the media, which will lead to inefficient use of impact energy. An unfavorable rheology can also lead to overgrinding or centrifuging of the slurry inside the mill. Slurry rheology also affect classification, with higher viscosity increasing the cut size. In this article, the causes of the rheological effects on autogenous grinding and hydrocyclone classification have been discussed. Both plant and pilot scale data from autogenous grinding have been provided to show the effects of viscosity on specific energy con- sumption and other breakage characteristics of the ore. It is shown that: (1) high viscosity, produced by low temperature and high fines content, significantly increases the specific energy consumption and the production of critical size material in an autogenous mill; (2) In hydrocyclone operation, increasing the viscosity causes the d50(c) size to become coarser.

Jan 1, 1998

By L. W. Saperstein, W. W. Kaufman

Stimulated by the hearing protection clauses in the 1969 Coal Mine Health and Safety Law, attempts were made to determine what safety hazards, in terms of warning signal discrimination, are attendant upon the wearing of hearing protectors. Warning signals of dangerous roof conditions were collected and analyzed from 11 different coal mines in four different coal seams. Primarily, signals of audible level emanating from roof, floor, or coal were recorded. The interpretations of these signals were seen to be very dependent upon coincident visual and tactile signals. Acoustic character of such signals is shown to be dependent upon the spectral energy distribution of the pulses. Roof talk signals generally have broad-band spectra concentrated below 5 kHz. Reverberation times of acoustic pulses are generally less than 0.5 sec in duration. Indications have developed which link the coal mine entry dimensions with the nature of noises recorded there. Related experiments suggest that roof talk can be discriminated from background noise equally well when wearing protection as when not. This conclusion is only appropriate when noise levels warrant the wearing of protection. When quiet, the wearing of protection somewhat reduces discriminatory ability.

Jan 1, 1976