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By D. Harrington

"Up to the last 10 or 15 years, responsibility for accidents in mines was generally, though not universally, placed upon the person or persons immediately involved. Present-day thought is rapidly veering toward holding the industry responsible for accidents, with ultimate payment of the bill by the consumer, if financial expenditure should be necessary. While it is undoubtedly correct in principle that responsibility for accidents in and around mines should be shouldered by the employer and while it is probable that as time passes the burden will become even more definitely than now that of the mining companies, on the other hand it is an undeniable fact that large numbers of accidents occur through acts of omission or of commission of some person, very frequently the victim of the accident being the offender.Out of about 3,000 persons killed every rear in our -mines and quarries, nearly half or approximately 1,500 of the fatalities are due to falls of overlying material or of persons, about 500 to haulage, about 350 to fires and explosions, about 125 to explosives, approximately the same number to electricity, and about 300 to various miscellaneous accidents.Generally the accidents from falls involve but one or two persons at a time, and the tendency is now as it always has been to charge the victim or possibly a coworker with the responsibility. Usually this sort of accident occurs at or near a working face (statistics indicate that about 80 per cent of fatalities from falls of roof or rib occur near the face), and as it is Generally agreed that it is the duty of the worker to keep his working place safe, the worker and especially the face worker is given the blame in case of accident."

Apr 1, 1930

By J. de V. Lambrechts

A critical comparison of specific cooling power and the wet kata thermometer in hot mining environments By J. de V. Lambreehts. D.Sc. (Eng.) (Rand) A new formula for the wet kata thermometer has been established in place of the currently used one which is believed to be fundamentally wrong and the new formula is compared with the recently proposed specific cooling power concept. Apart from a constant multiplier, it is concluded that the difference between. the two concepts lies solely in the value of 'n' in the function vn and that this value for the cooling power of air on the sweating human body remains to be established reliably. The kata thermometer might yet be found to be a reliable predictor of heat stress in hot environments.

By Sylvia S. Eskander, Sherif S. AbdelSalam, Mona B. Anwar

Expanded Polystyrene (EPS) geofoam has long been used in numerous geotechnical applications due to its lightweight and durability. Among these applications is the use of EPS as an alternative fill material to conventional roadway soil embankments. This study investigates the benefits of using EPS roadway embankments to reduce the induced stresses and strains on the underlying peat and soft clay. Firstly, mechanical and interface properties of the EPS were acquired from a companion study that also considered the cyclic loading and creep effects. In order to determine the actual stress-strain distribution within the EPS blocks, a physical prototype was developed in this study with overall dimensions of 1.2 x 1.0 x 0.5 m, with a density of 35 kg/m3. The prototype EPS blocks were subjected to cyclic loading with intensities ranging from 10 to 50 kN. Then, a numerical model was developed to simulate the behavior of EPS roadway embankments. The numerical model outcomes were verified against the prototype measurements. A parametric design study was also conducted to develop a correlation between EPS embankment height and the stress-strain that occur in the underlying strata. Results showed that EPS embankments could reduce stress and settlement in the underlying soil by about 40% and 54%, respectively. EPS APPLICATIONS AND BACKGROUND Expanded Polystyrene (EPS) geofoam blocks have been effectively used during the past several decades in numerous geotechnical applications. EPS static and dynamic properties as well as interface behavior were extensively characterized in various published studies such as that conducted by Horvath, 1994; Stark et al., 2004; Zarnani and Bathurst, 2008; Trandafir et al., 2010; Athanasopoulos et al., 2012; AbdelSalam and Azzam, 2016; and others. However, to be able to use locally produced EPS blocks, its physical and mechanical properties must be thoroughly determined. The lightweight and compressible material of EPS geofoam makes it suitable both as a backfill and for absorbing pressure in both the vertical and horizontal directions. Kim et al. (2010) adopted EPS as an alternative for soil backfill around buried pipes; their model showed a reduction in the vertical stress acting on the pipes by up to 36%. Oshati et al. (2012) presented a case study of a field-instrumented box culvert with EPS blocks on top, which reduced vertical stress by 58%. Meguid et al. (2017) used an EPS inclusion to surround culverts and achieved up to 72% stress reduction, depending on the EPS density and the culvert depth to width ratio. AbdelSalam et al. (2017) used a relatively thin EPS inclusion behind flexible cantilever retaining walls, verifying that the lateral pressure can be significantly reduced by 25%; they also developed a design chart for this application. Moreover, AbdelSalam et al. (2019) investigated the use of EPS as a lightweight alternative for soil backfill above shallow tunnels. It was found that EPS had created a differential movement between the wedge located above the tunnel and the neighboring soils, which accordingly reduced the vertical stress acting on the tunnel by 85%, due to the use of lightweight EPS material and positive soil arching.

Jan 1, 2019

By Gregory M. Rumbaugh, Todd Kostecki, Christopher Mark

From 2015 to 2021, five massive pillar collapses occurred at four underground stone mines in the eastern United States. These events resulted in powerful airblasts that damaged mine infrastructure and mobile equipment, seriously injured miners, and disrupted underground travelways. Each of these pillar collapses propagated through the overlying strata, causing a subsidence basin on the surface. Pillar collapses are particularly hazardous for miners because they can occur with little warning and can affect miners that are far from the pillar collapse area. The following case studies show that certain factors may increase the likelihood of a pillar collapse. For instance, each of the five events involved the collapse of at least twelve benched pillars with width-to-height ratios (w/h) of 0.8 or less. This study elaborates on

By D. Lauriski, E. D. Thimons, A. C. Smith, D. C. Fredley

The National Institute for Occupational Safety and Health (NIOSH) and Northwest Barricade LLC (NWB) conducted a study to evaluate the effectiveness of a novel fire blocking gel for use in underground coal mines to extinguish or retard the growth of a coal fire. The gel agent was subjected to controlled laboratory testing to assess its ability to delay coal ignition. It was then evaluated to determine if manual fire hose application could be used to apply the agent to mine roofs and ribs to provide a safe egress for mine rescue teams from a fire area. The gel agent was also evaluated in a water sprinkler system to determine its potential for use in conveyor belt fire suppression systems. The agent was then tested in live-fire exercises to examine its effectiveness in retarding and extinguishing a deep-seated coal fire and wood fire. Lastly, the ability of a mine rescue team to quickly and safely apply the gel agent to a mine entry during a simulated mine fire exercise was determined.

Jan 1, 2011

By Thirnbeck M, Sione T, Petrie P, Leach TM, Mori W, Digan K, Harry K

Gold and lesser copper mineralisation are associated with porphyry-related vein systems periph-eral to two separate inferred intrusive centres north of Kainantu, Papua New Guinea (PNG). The intersection of NW trending structures, formed parallel to the Markham Fault, with NE trending transfer structures localise porphyry intrusions, and control vein distrib-ution.The Arakompa veins intrude pre-existing fractures in Akuna granodiorite, located proximal to an inferred porphyry. These veins are characterised by early quartz and later pyrite-chalcopyrite. Gold mineralis-ation is associated with Bi-Te phases in the sulphide veining. At Maniape, en echelon gash veins occur within the imbricate portion of a regional structure. Maniape is a high level carbonate-base metal gold system formed distal to the same porphyry source as Z ?-;4 kmmna

Jan 1, 1994

By Darío Zegarra

El control de leyes es una de las operaciones mineras más importantes puesto que genera especificaciones exigentes para los productos finales, así como minimiza la contaminación, manteniendo los límites de ciertos parámetros de calidad. Sin embago, existe un problema con el método de programación lineal durante el planeamiento de mina. En ese sentido, el presente texto destaca dichos problemas - en tanto existe un manejo estricto de los precedentes en la operación minera y hay una falta de flexibilidad y fácil manejo. Por ello, se han desarrollado sistemas que superen las deficiencias generadas por las firmas proveedoras de equipos como CATERPILLAR, GEMCOM, DATAMINE y VULCAN, combinando las ventajas de un software gráfico con la estrategia de perfeccionamiento de la Programación Lineal.

May 25, 1998

By Eldridge Haynes

IF you ask the average American to define 'total war' he is apt to fumble for an answer. But in Britain everyone knows the answer, because Britain has mobilized its total labour force, including women. If we were to match, proportionately to our population, Britain's mobilization of labour, we should have 60,000,000 people working full time in the armed services, civilian defence, and war industries. Actually we have fewer than 35,000,000 so employed. In Britain two out of every three persons between the ages of fourteen and sixty-five are so engaged. For the first time in the history of any democracy Britain conscripts women for service in the army, navy, and air force. Two hundred thousand British women have been conscripted for the army, known as ATS, meaning Auxiliary Territorial Service. There are more women in the air force than the total personnel of the RAF at the outbreak of the war and almost all of the land base jobs of the British navy are now handled by women. In addition to cooking and office work, Britain's women soldiers and sailors are driving trucks and motorcycles, repairing motor vehicles, packing and repacking parachutes, installing, inspecting, and maintaining gun equipment and ammunition of combat planes after each raid, raising and lowering barrage balloons, forecasting weather, manning harbour craft, sending and receiving radio messages. A normal ack-ack unit is composed of 229 women and 189 men. The women man the gun height finders and predictors, give bearings, and signal to fire.

Jan 1, 1942

By R. J. Zagrocki

Rekindled public concern about lead toxicity has intensified the awareness of lead-bearing materials in contact with the environment and the human population. Lead's common association with other metals makes the increasingly restrictive lead standards a primary concern for a large number of metal and metal-related industries. In commercial scale demonstration tests with lead-bearing wastes, the HRD Flame Reactor process has a demonstrated ability to separate and recover over 95% of the lead as a recyclable oxide, while rendering the remainder of the material as vitrified, non-leaching, and nonhazardous co-product. Recent Flame Reactor process tests and preliminary cost data for secondary lead soda slag are highlighted.

Jan 1, 1992

By Guy Bridges, Elton Ko, Cheng Ting Ning, Owen Ng, Giovanni Chang, Robert Anderson

"PROJECT OVERVIEWThe Liantang/Heung Yuen Wai Boundary Control Point (BCP) and Associated Works will be the seventhland crossing between Shenzhen and the Hong Kong Special Administrative Region (HKSAR) of China.The project includes site formation of about 23 hectares of land for the development of the BCP and anapproximately 11-kilometre (km) long dual two-lane trunk road (the “Connecting Road”), connecting theBCP with the existing Fanling Highway. The route alignment is within a relatively rural area of HongKong, with very limited similar infrastructure works carried out nearby. It passes beneath bothmountainous terrain, and alluvial plains, and falls within an area of several major regional faults andassociated metamorphism, resulting in a complex variety of ground conditions.ALIGNMENTThe Civil Engineering and Development Department of the Government of the Hong Kong SpecialAdministrative Region carried out extensive public engagement in selecting the alignment of theConnecting Road. Over 70 consultation forums with public bodies, including the District Councils, RuralCommittees, local representatives, etc. were held during the alignment design process. In order toalleviate the concerns of various nearby villages, and to minimize land clearance and environmentalproblems, the original alignment of 10 km long (3.5 km of tunnels and 6.5 km of viaducts) was revised toits final alignment of 11 km long which comprises 5.7 km of tunnels, 4.3 km of viaducts and 1.0 km of atgrade roads.The finally adopted alignment commences at the southern end with an interchange with the existingFanling Highway, part of Route 9, which is a dual three lane expressway currently being widened to dual4 lane. Alongside the expressway is the main rail connection to the mainland of China, and theinterchange viaducts connecting to the southern portal of the Lung Shan tunnel must cross over thisrailway. The southern portal is located in the foothills of Lung Shan, and the 4.8km long tunnel is alignedin a north-northeasterly direction. The southern half passes under mountainous terrain of Lung Shan,and then crosses a valley containing the Kwan Tei river. The northern section comprises low hillsseparated by an alluvial plain and Tan Chuk Hang village area. At the northern end, the tunnel turns tothe north-west to connect with Sha Tau Kok road, an existing single carriageway road, with a newroundabout interchange. Mid-way along this tunnel there will be a ventilation building, connected to the main tunnel by a 330m long ventilation adit. To the north-western side of this interchange is the900m long Cheung Shan tunnel, and after this the remaining 4.3km of the highway connecting with theBoundary Control Point is to be constructed as an elevated viaduct. The alignment is shown in Figure 1."

Jan 1, 2016

By D. Minson, G. Lindner, S. Miskovic

Thickening is an essential process in the mining industry and currently one of the most costeffective technologies for recovering water from tailings streams. Improved performance of thickeners can lead to significant energy savings, and increased recovery of water close to the mill. Its performance is directly affected by the rheological properties of slurry at the raking zone. To further understand the dynamics of slurry inside thickeners, a multiphase particle-in-cell method (MP-PIC), is used to investigate its behaviour on a sliding channel. Parameters like particle-size distribution (PSD), rheological properties, and domain discretisation were benchmarked to study its influence on highly dense flows. The slurry concentration by weight of the samples ranged between 60 to 70% of solids by mass, under which conditions it is known to behave like a non-newtonian fluid. An experimental flume, 0.2 m wide and 2 m long, was used for validation under different angles and slurry composition. Visual analysis of the slurry height and shape, as well as velocity measurements, were compared with numerical data. The preliminary results show the ability of MP-PIC method to represent different types of highly dense flows, while still being computationally affordable and practical for industrial use. Keywords: High density thickener, CFD, MP-PIC, multiphase-flow

Jan 1, 2020

By Chris A. Minnucci

In 1978, the U.S. Department of Energy funded a 2-year study to identify and quantify causes of the post-1969 coal mine productivity decline. A large number of factors hypothesized to have affected productivity during this period were analyzed using regression techniques. The results were particularly interesting for two of the factors--mining method and shift scheduling. The study results indicate that the use of longwall mining has an insignificant impact on overall mine productivity, compared to other methods, and mines operating on a two-production shift per day schedule are more productive than mines employing other shift schedules.

Jan 1, 1984

By N. H. Jensen

SINCE the sixties, Utah has been one of the leading metal mining states of the Union. During the last fifteen years its mines have supported the largest smelting center in the world. Its rank as a metal producing state is reflected by its 1924 production which had a value in excess of $65,000,000 making it the leading silver producing state, third in both copper and lead and sixth in gold production. During the past year, metallurgical developments for the recovery of zinc contained in lead ores has made rapid progress so that the future zinc output will be of substantial importance. The largest silver mines of the nation and the world's largest open cut copper mine are within its borders. Settlement of Utah started in 1847, with the advent of the "Mormons," and originally the area of the state was much greater than now. The first metal mining

Jan 1, 1925

By R. Hurman Eric

The flow of molten slag and matte and the estimation of the mass of settled matte in electric furnaces is discussed and the action of the electric furnace as a settler is considered. Particle size of the concentrate and its grade are major contributors to settler dimensions. Discussion on the production capacity of the electric furnace with reference to operating current, power input, furnace dimensions such as width and length and electrode diameter are given. These discussions are based on considerations derived mainly from experimentally determined properties of the slag such as its resistivity, viscosity and liquidus temperature. Extension of the design and operating considerations to circular furnace symmetry is also discussed.

Jan 1, 1995

By CIM CIM

Why Workplace Important! ?We need Diversity is to do more in the industry as a whole to encourage and support diversity. It has long been an industry of white dudes and we?re not going to survive if that?s how we continue to think.? ? Mark Scott, HR Superintendent, Vale Inco PURPOSE OF MINING FOR DIVERSITY ? Share best practices in the areas of HR Development ? Support industry in attracting, recruiting and retaining a diverse workforce ? Raise awareness of industry HR challenges and collaborate with stakeholders to develop sustainable HR practices

May 1, 2009

By Alfred Goldberg

The paper is founded on the results of an investigation on the softening behavior of a cold-rolled low carbon steel. This specimen, originally cold rolled 15 , 30 , 50 and 75% reduction in thickness, were annealed at several temperatures ranging from 481 to 687ªC. A temperature-time range was encountered over which strong competition between these processes was evident. An interpretation on the effect of test variable on determining which one of the competing processes dominated during annealing is presented.

Jul 20, 1961

By Wilson. D.

The Vaal Triangle Branch of The South African Institute of Mining and Metallurgy was established on 20th November, 1986, at a meeting enthusiastically supported by local members. In attendance were special guests Dr H. Wagner (President, SAIMM) and Dr O.K. H. Stefen (Junior Vice-President, SAIMM).

Jan 1, 1987

By Jurgen Weissflog

Why, where and since when using shiftable conveyors? Advantages of this equipment The ever increasing demand for bulk materials such as ore, coal, lignite, oilsand, oilshale and bauxite requires mainly an opencast operation. To exploit these materials huge amounts of overburden and partings must be transportes by means of conveyors, trucks or trains. When analyzing the various opencast mines it can be established that there exist only two basic types of mining systems, i. e., the discontinuous strip mining system as used in the USA (Fig. 1) and the continuous mining system as is commonly applied in Europe. The reason why these two mining methods have been developed parallel to and independently of each other to such a high technical standard results from the varying geological conditions of the mineral deposits.

Jan 1, 1983

By M. G. Benz, J. F. Elliott

The austenite solidus of the iron-carbon system has been determined using a series of diffusion couples, each of which consisted of a specimen of austenite held in contact with a melt saturated with austenite. After the equilibrium distribution of carbon had been established by diffusion at a specified temperature, i.e. the austenite specimen had become austenite of the solidus conzposition, the diffusion couple was cooled, sectioned and anazlyzed for carbon. The solidus was found to be a straight line: A revised iron-carbon temperature-composition diagram is presented, COMPOSITION has a marked effect on the temperature at which austenite begins to melt and the austenite solidus of the iron-carbon system describing this effect has been the subject of many investigations.1-10 The significant results of these investigations are presented in Fig. 1. The experimental methods and purity of the materials used in them are summarized in Table I. In plotting the data in Fig. 1 no attempt has been made to convert these results to the International Temperature Scale of 1948," except for the data of Adcock,5 as this conversion would do little to reduce the uncertainty that exists as to the position and shape of the solidus. A point of major concern in evaluating these data is that the alloys studied, except those used by Adcock, were not binary alloys of iron and carbon, Table I. Also, it would appear that several of the methods did not permit equilibrium to be established through the system being studied. All that can be said for the results of these investigations is that they indicate only approximately the location of the solidus with the uncertainty as to its location at 1 pct C being approximately 100°C. The current investigation was undertaken to provide reliable data by which the austenite solidus could be established. It was hoped that information on the liquidus also could be developed at the same time, but experimental limitations prevented this as austenite segregated from the liquid on cooling. After a careful study of possible experimental methods and extensive laboratory tests, it was decided that the use of a series of austenite-liquid diffusion couples would provide the most reliable results. This paper describes the method and its results and also includes a complete iron-carbon temperature-composition diagram based on what are considered to be the best available data. EXPERTMENTAL METHOD The diffusion couple used for this investigation consisted of a small cylindrical pellet of austenite held in contact, at a specified temperature, with a melt saturated with austenite. The composition of the cylindrical austenite pellet was chosen to be approximately 0.1 wt pct C less than the estimated

Jan 1, 1962

By Dian Adisty, Leiv Kolbeinsen, Eli Ringdalen

In Si and FeSi production, the main Si source is SiO2, in the form of quartz. Reactions with SiO2 generate SiO-gas that further reacts with SiC to Si. During heating, quartz will transform to other SiO2 modifications with cristobalite as the stable high temperature phase. Transformation to cristobalite has been investigated and shown to be a slow process where the rate varies between the investigated quartz types. The effect of quartz versus cristobalite as SiO2 source has been studied for reaction (1) 2SiO2 + SiC = 3SiO + CO, by heating of pellets with SiO2 + SiC in Ar-gas. The reaction was faster with cristobalite than with quartz. Initial experiments indicates that this is the case only in Ar and not in CO-atmosphere The higher specific surface area of cristobalite is believed to contribute to the higher rate. The industrial consequences of the observed difference between quartz types are discussed.

Jan 1, 2014