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By Vasundhara

Underground coal mining in soft floor environments has often led to strata control problems ranging from small scale issues such as floor heave which disrupts traffic and ventilation, rib spalling and induced fractures in pillars, through to large scale instability and long term subsidence. Past investigations of the problems encountered in Newcastle Coalfields of New South Wales, Australia, have revealed that the soft floor unit comprises of claystone which is very sensitive to moisture. It is prone to swelling, reduction in stiffness and loss of strength in the presence of moisture. Long term stability of mine panels in such an environment is governed by the extent of deterioration of the floor strata. The paper reports the field investigations conducted at Cooranbong Colliery to assess the extent of softened floor zone in the roadway and under a pillar.

Jan 1, 2001

By J. C. Pandey

The paper highlights the experimental investigations to characterize texture and plastic strain ratio r-Bar in auto grade steel sheets by ultrasonic measurements, whereas attempts were made to characterize interlamellar spacings in pearlite, tensile stresses and torsional properties in prestressed concrete wires by eddy current measurements. Good correlations were obtained between the testing parameters (such as ultrasonic attenuation and velocity in case of steel sheets as well as eddy current out put voltage and phase angle in case of steel wires) and the materials properties (such as texture, plastic strain ratio r-Bar, interlamellar spacings in pearlite, tensile stresses and torsional properties). 15 MHz normal direct contact and 20 MHz delay line normal shear wave probes were used for ultrasonic measurements. Eddy current measurements were done using an absolute coil probe with variable frequency selection. The experimental results show the possibility of nondestructive on line measurement of the above microstructures and properties.

Jan 1, 2010

Today computers are accepted as a standard item in industry and they perform a variety of tasks over a wide spectrum of activities from mine planning and CAD to data processing and spreadsheet work. However many problems particularly in the. area of decision making where there are no clear mathematical models available and usually the output or answer is dependent to some extent on a heuristic approach, don't lend themselves to conventional solutions using standard procedural algorithms. Recently a number of techniques have evolved primarily from the enhanced capabilities of modem equipment, which are capable of solving these problems. This paper is a brief overview of these rather unconventional developments of computer technology in the area of artificial intelligence with reference to their application in mining.

Jan 1, 1993

By Donald Carlisle

El presente texto describe las relaciones entre costos, utilidad, cantidades y velocidades de "recuperación" de la mena, así como se consideran las leyes marginales y su velocidad de la recuperación en las minas.

Jan 1, 1970

By Dale Preece, Ayman Tawadrous

This paper presents a number of examples of three-dimensional blast modeling in both surface and underground environments that include time-delay explosive decking. These examples include: 1) quarry blasting, 2) coal seam protection blasting, 3) mineral mine blasting with high energy time delayed decks, and, 4) underground single-level/single-shot drawbell blasting.

Jan 1, 2014

By Tim O’Neil

The earthmover tire shortage has been a case of bust and boom for the tire industry. Tire producers were unwilling to invest ahead of the mining boom. In their defense, though, the metals sector of the mining industry tends to be cyclic, tire manufacturers are not prescient. Until two years ago, low tire demand depressed prices. The incentive to invest in new, big-tire capacity was almost nonexistent, according to Prashant Prabhu, president of Michelin Earthmover Tire worldwide. “There has been very poor anticipation or a miscaluation of the amplitude of the (tire) demand on the part of just about everybody,” said Prabhu. What a turnaround. The earthmover tire market has grown by 30 percent over the past two years. Now there are not enough earth-mover tires and likely won’t be for the next two years. Goodyear said it was offering customers bias-ply tires when it could not supply enough radial-ply tires. Komatsu said it lost equipment sales because it could not provide the tires that customers requested. Volvo and Caterpillar said they are delivering some vehicles without tires, either promising tires later or leaving the customers – mine operators – to find their own rubber.

Jan 1, 2006

By Donald M. Ulbrich

Any of you who served in the military remember the admoniton to "get the lead out," In the military environment, where cost wasn't always a factor, "get the lead out" was more often a call for activity of any sort than activity of a particularly productive nature. As a result, when the top sergeant yelled "get the lead out," lots of people started moving.. . usually to get out of his way. Now there's a new cry, ..one that comes not only from the military but from an entire nation threatened with dependence on foreign sources for its energy needs. That cry ...get the coal out, Like the earlier order, it's a call to activity. A signal that the coal reserves of the United States must be tapped so that Project Independence can succeed by 1985, But it's more than a mere call to activity; it's also a call to achieve productivity. ,a call to produce coal both efficiently and acceptably. And that leads us to the key questions of where the coal is going to come from to meet that 1985 goal, and how can it best be mined. Where will the coal come from? There's no doubt much of it must come from surface mining in the West. How can this coal be mined? There are several options available but there is an excellent case to be made for using mining shovels and haul trucks due to their versatility in stripping, loading and reclamation, We'll explore this approach in this talk today.

Jan 1, 1976

By H. W. Mead, C. E. Birchenall

SELF-DIFFUSION of cobalt has been investigated by Ruder and Birchenall,1, 2 Nix and Jaumot,3 and Gruzin.4 The results for a given tem- perature differ by a factor of about six in the extreme cases with no really close agreement between any two sets of data. The first two groups of investigators employed the decrease of surface activity method. Since Ruder and Birchenall have shown that the values obtained from this method are sensitive to the surface preparation, it seemed desirable to perform a few check experiments by a method not open to this objection.

Jan 1, 1956

By Huimin Lu, Lian Zhou, Panpan Wang

"For the low concentration C02 exhaust gas from coal-fired power plant, steel plant emission trapping and recycle problem, a pressure swing adsorption process was studied, using a porous imidazolate framework materials (ZIFs) as adsorbent, separating carbon dioxide from fuel gas mixture. In the carbon dioxide reduction condition by electrochemical method, using ionic liquids as electrolyte, the oxygen and carbon products could be obtained, including carbon nanotube, nano carbon fiber and amorphous carbon. At last, a new C02 collection, recycling and reuse technology was formed.IntroductionDuring the combustion of fossil fuel in coal-fired power plant or steel plant, large amount of carbon dioxide has continuously emitted into the atmosphere. The phenomenon has resulted in the melt of arctic glacier and the frequent emergence of abnormal climate. How to reduce the emission of carbon dioxide and protect human living environment has become a worldwide challenge. Recently, there are three routes to resolve this problem: The first one is to adjust the energy structure and develop new energy, such as solar, wind, hydrogen; the second one is to improve energy efficiency and avoid waste; the third one is to research capture and sequestration of carbon dioxide (CCS). But many researchers have come to realize that the recovery and utilization of carbon dioxide are more important than the sequestration of it. Because the captured carbon dioxide just buried under the earth maybe cause secondary pollution if carbon dioxide leak out from the adsorbent."

Jan 1, 2013

By H. J. McQueen

Mineral and energy resource consumption were continuously reduced by process improvements as chemical understanding was developed and applied. During the past two centuries, technological improvements increased human productivity that was accompanied by social advances and labour saving products; however, these sometimes proliferated to endanger sustainability, e.g., automobiles. In the steel industry, precisely controlled rolling of HSLA steels required little extra mineral consumption but reduced weight and heat-treating energy. Continuous casting of slabs reduced scrap compared to ingots and energy for the homogenizing soaking pit. Al alloy extrusions were improved by retaining the strengthening in the near-surface substructure, of high strength textures and of press quenching that is suitable for direct age hardening. Continuous bar casting of Al-0.65Fe, coupled with rod rolling and followed by wire drawing with only a final recovery anneal, yielded electrical wiring for households to replace less plentiful Cu and later for light-weighting use in autos and aircraft Looking backwards, the 1970 decade saw the first oil crisis and inspired Ottawa to undertake a campaign to develop an energy strategy that would decrease dependence on imported fuels. One significant undertaking under Energy Mines and Resources was the organization of industrial energy conservation, managed by each industry association,that collected detailed current statistics and set the goals for a 2-year campaign. The metal producing industries, as compared by E.C.N. Perryman to about 7.2 exajoules (EJ) for the nation, consumed about 0.8 EJ, being about one third of all heavy industries. While manufacturing consumed 30.2% of total energy, it created 87.3% of total national dollar value. Within the industrial envelope, smelting and refining utilized 28% (0.67 EJ, mining beneficiation 6.7%, 0.16 EJ); there was a significant contribution to exports: 80% of iron ore and 70% of aluminium in 1973. A general concern was that decreases in ore grade would lead to a rise in energy expenditures countering benefits from processing efficiency.

Jan 1, 2012

By Marco Herrera

Con el objetivo de minimizar los impactos ambientales respecto a la generación de sedimentos y de no impactar ni la vida acuática ni a los usuarios de las referidas cuencas de contribución, la minera Yanacocha desarrolló el plan integrado de manejo de aguas superficiales para identificar fuentes de impactos potenciales en la generación de sedimentos y analizar qué medidas de mitigación requieren ser implementadas. En ese sentido, el presente texto señala un sistema de control de sedimentos y erosión aplicado a la minera Yanacocha, donde se desarrolle un monitoreo permanente de los trabajos de disturbancia de una área de terreno, de forma que se garantice el impacto sobre la erosión de las áreas afectadas, se protege la vida acuática de las cuencas de distribución de la minera y no se genere sedimentos.

Sep 12, 2005

By D A. Manhire, R M. Flores

The commercial develop of coalbed methane from the Powder River Basin has demonstrated that low-rank coals can be a viable source of gas. Currently over 20 000 coalbed methane wells exist in the Powder River and it is predicted that there will be 50 000 wells by 2010. What makes the Powder River Basin successful is the thickness of the coal (in excess of 30m) as well as the low ash content (

Jan 1, 2002

By Jin Qiu

Experiments were performed to determine the extent of minor element elimination that occurred when mixtures of copper smelter dust and copper concentrate, were calcined under vacuum. Almost complete removal of the As, Sb, Bi and Pb occurred due to the conversion of the minor element compounds of these elements into their highly volatile sulphides by reaction with sulphur from the concentrate. Heat and mass balance calculations of the slag-blow in a copper converter found that ~30 tonnes of the vacuum calcine could be used to produce 100 tonnes of copper as white metal. The use of dirty concentrate as the sulphidizing agent in the vacuum calcination means that the minor element treatment capacity of the smelter complex could be increased by 60 %. Also the productivity of the converters may be increased by up to 8 % due to the supply of copper values and oxygen in the calcined mixture.

Jan 1, 2005

Jan 1, 1892

By John V. Beall

The "free form life," The Wall Street Jourlzal called it. That is what the young people are practicing who have dropped out after successfully completing a college education. The ones described were first-rate students who did not embark on careers but instead selected such nonintellectual jobs as delivering mail, short- order cooking and the like. We couldn't help thinking that it wasn't so long ago, that we had the ideal setup in mining for folks of this persuasion when most college grads were started out as muckers. Actually there isn't much new in this business of doing your own thing. Being a type that takes westerns seriously, we jumped at the chance to catch the rerun of the wide-screen flick "How the West Was Won." There was Jimmie Stewart playing the part of the mountain man, with a canoe full of furs going east down river. Coming west up river, is a settler with his daughters. This mountain man had on his fringed buckskins, his two-year growth of long hair and a tremendous thirst. He had been doing his thing and planned to keep right on doing it. However, one of the pretty settler girls had other ideas. The same fate probably awaits today's individualistic youths.

Jan 1, 1970

By A. D. Davis

Naturally occurring arsenic has been detected in water from inactive mines and several wells in the Keystone area of the Black Hills. Keystone City Well #4 showed a total arsenic concentration of 69 parts per billion (ppb) during pumping in 2004. The well is not used currently except for arsenic-removal research. Water also can be pumped from a mine shaft in the abandoned Keystone ? Columbia ? Bullion gold mines, whose interconnected workings flooded after mining ceased in the 1930s. This water has been considered for local supplies, although it would require treatment or blending because of arsenic concentrations. According to historical records, the Bullion Mine produced 100,000 pounds of white arsenic. An aquifer test on the mine workings was performed at a pumping rate of about 550 gallons per minute. The arsenic concentration in pumped water was 33 ppb. In addition to wells within Keystone, samples from the water supply at nearby Mount Rushmore National Memorial have shown arsenic concentrations greater than 10 ppb, the U.S. Environmental Protection Agency?s maximum contaminant level for arsenic in drinking water. Limestone-based technology for removal of arsenic from drinking water is an innovative and promising method that has been considered for treatment of water at Keystone. In batch testing with water from Keystone Well #4, limestone removed about 65% of arsenic from solution. A related problem of arsenic removal from drinking water involves disposal of the waste product, which is critical for commercial viability of removal technologies. Current research is investigating thermal stability of the waste in order to determine the potential for recycling of the material during manufacture of cement.

Jan 1, 2010

By C. R. Knopp

Gas-oil relative permeability ratio is an important relationship in oil reservoir predictive calculations. A correlation has been developed from 107 gas-flood k/k tests on Venezuelan core samples. The correlating parameter is based on restored-state water saturation tests and' is applicable to both consolidated and poorly consolidated sandstone reservoirs. Data of the correlation show that there are no distinguishah1e differences between the mass-data groupings for the two c1assifications A procedure is recommended for running .sufficient relative. permeability analyses to compute a geometric mean of the sample group. The geometric mean is more representative of the total core, and probably the entire reservoir. For example, while only one in four of the k,,/k,., test curves agreed closely with the resultant correlation of this report, the geometric mean curves of the 16 suites (three samples or more). showed good agreetment ill three cases out of four. INTRODUCTION The gas-oil relative permeability ratio is an important, fundamental relationship in most oil reservoir predictive calculations. Predictive calculations are made to estimate future reservoir production characteristics and ultimate oil recovery. The k1,/k2, relationship is specifically needed to relate the surface gas-oil ratio to the reservoir oil and gas saturation, and to calculate the relative movement of these phases within the reservoir whenever some of the more complex driving mechanisms are present. Laboratory k1/k2, tests are not generally run as a routine analysis. Consequently, k1/k2 data often are not available when needed because the cost of laboratory work could not be justified or the need for such data had not been properly anticipated. When laboratory k1/k2, data are available, they are often very difficult to interpret. For example, wide divergence is sometimes shown in a family of k1,/k1, tests representative of the producing horizon in a single well. With these considerations in mind, a study was made to determine if a relationship might exist between the k1,/k2, curve and some other simple laboratory test criteria. The most probable k1/k2, curve correlation for Venezuela described in this paper is the result of the investigation. The presented correlation defines the most probable gas-flood k,,/k,, curve through the medium of air-water capillary displacement and centrifuge water saturation tests. The laboratory procedures of these tests are. relatively simple, and inexpensive; test data should be. widely available- from routine analysis. DATA AVAILABLE, LABORATORY METHODS The report correlation utilized 107 gas-Hood k1/k2, tests run on sandstone cores of Venezuelan reservoirs. Table 1 is a general tabulation of data pertinent to the tests, while Table 2 summarizes the data. Thetests include 96 from Western Venezuela and 11 from Eastern Venezuela. Eighty-two- of the 107 test samples were sandstones that varied from poorly consolidated to-unconsolidated; 25 were consolidated. The average sample porosity was 26.7 per cent and the average permeability was 1,121 md; these values typify the better sandstone reservoirs of' Venezuela. The Welge gas-flood technique,' based on fundamental Buckley-Leverett frontal displacement theory, was introduced in about 1952 and is widely accepted in the industry. The laboratory procedure is relatively simple, rapid, and can be performed on small core samples. While there have been some minor variations in sample preparation and laboratory procedure in the tests used for the correlation, these tests can be generally summarized as follows. The core sample was first sol vent-extracted and dried. Connate-water saturation was restored by the oil-flushing or evaporation-blow down methods. At the beginning of gas flood the hydrocarbon pore volume was completeiy saturated with the test oil phase. Unsteady-state gas-oil displacement then began with the injection of nitrogen or helium. while the displaced oil and gas phases were incrementally metered at the out-flow face. From the test data, the k,,/k,, curve was calculated by the Welge method.' The individual oil and gas relative permeabilities were also calculated." CORRELATING PROCEDURES In attempting to establish a basis of correlation, we found that broad mid-range sections of 105 of the 107 k,,/k,, test curves could be closely duplicated by a straight line. Only two curves did not show a degree of linearity in this region. Correlation-curve definition parameters were subsequently developed from this observation of consistent mid-range linearity. Possible correlating variables were limited to the physical properties measured on core samples that (1) were widely available as common test data and (2) could be easily and cheaply obtained through future laboratory work. The more obvious possibilities were porosity, permeability and

Jan 1, 1966

By E. M. Stiles

THE Wellington Lake power plant of the Consolidated Mining and Smelting Company of Canada, Limited, about 25 miles from Goldfields, Saskatchewan, is the second hydro-electric project operating in that Province, the first being the Island Falls plant of the Churchill River Power Company which serves the operations of the Hudson Bay Mining and Smelting Company at Flin Flon, Manitoba. The Churchill River project develops 90,000 h.p. at 56-ft. head; the Wellington Lake plant 3,300 h.p. at 75-ft. with pro-vision for an additional 3,300 h.p. unit. Churchill River power is trans-mitted at 110,000 volts over a 58-mile line of steel towers to Flin Flon and an additional 45 miles over a wooden pole-line to Sherritt-Gordon. Our steel tower-line is 22 miles long, and the voltage is 60,000; this choice be-cause certain such equipment was available from Trail. The diversion of 15,000? second-feet at 56-ft. head for 90,000 h. p. at Churchill river dwarfs our 500 second-feet flow at 75-ft. head for 3,300 h.p. In both cases, the main obstacles to be overcome during plant construction were the lack of transport facilities and the short open season. Let it be noted here that this paper deals mainly with those phases of plant construction which were particularly interesting to the writer. With-out these variations from the ordinary routine, this is just another power project whose story is better told by the accompanying charts and pictures. To many members of the Institute it is still just that; but I am writing for those who, like myself, have been too seldom responsible for major under-rakings at an appreciable distance from a railway siding. When it was planned in early 1937 to erect a 1,000-ton mill at our Box mine, both hydro and Diesel power were discussed. With ten years' ore in sight, even an expensive hydro project, such as ours turned out to be, produces kilowatts materially below the 2-cent operating cost of a Diesel plant using fuel-oil at 14 cents a gallon.

Jan 1, 1940

By C. Robinson

The Diavik Diamond Mine is located in one of the most remote and forbidding places in the world, 220 kilometres south of the Arctic Circle and on the bed of a vast northern lake, Lac de Gras. A single road, built out of ice and crossing frozen lakes, connects the mine with other operations and Yellowknife, the capital of the Canada's Northwest Territories. Diamonds were first discovered in the Lac de Gras region in the early 1990s, and construction of the Diavik Diamond Mine was completed in 2003. Diavik currently mines three kimberlite pipes. Open pit mining has now concluded and all three pipes are mined using underground mining methods. In early 2010, Diavik began mining and processing initial ore from its new underground mine; underground mining operations are expected to continue beyond 2020. The initial mine ventilation system was an exhausting (pull) system with fresh air supplied by a fresh air raise and a main ramp. Return air was exhausted via two raises and a secondary ramp. The system had a total flow capacity approximating 401-411 m3/s. With planned increased production and with changes in mining method, it has been proposed to change the mine ventilation system to a positive (forcing) ventilation system in order to meet projected increases in flow requirements of 566-708 m3/s. Extensive engineering work was developed in order to successfully achieve the changes in system configuration. In the proposed configuration, the main ramp is in an exhaust configuration and exhaust raises are converted to fresh air raise. A number of system implementation options were investigated and phased plans for system execution have been developed. The proposed changes to the ventilation system are substantial and involve extensive construction work. Work was commenced in 2011, each planned phase has been successfully completed to date, and system changes continue today in order to achieve complete system flow reversal and increased flow distribution. This paper details the design of the modified ventilation system and commissioning work which will allow the mine to meet its future production targets.

Aug 1, 2013

By E. R. Morgan

A series of manganese-rich ferromagnetic alloys has been studied. The alloys are based upon an interstitial solution of carbon in manganese. In each of the systems investigated, the ferromagnetic phase was found to be face-centered-cubic in structure. This magnetic phase is based upon the composition (Mn, X)4C; where X is a metallic element which has both a positive size factor with respect to manganese and a high positive valence. Typical elements of this type are aluminum, indium, and tin. Preliminary magnetic measurements indicate that the effective magnetic moment of manganese in the alloys is at least 1.0 Bohr magneton per atom. It is emphasized that the critical atomic separation beyond which ferromagnetism can occur will be governed by the electronic configuration of the manganese atoms. Lattice parameter measurements show that the ferromagnetic condition in the present alloys is associated with an increased atomic separation of only 3 to 6 pct compared with a hypothetical face-centered-cubic lattice of pure manganese. MANGANESE which is paramagnetic and not ferromagnetic in the pure state can become ferromagnetic if suitably alloyed. Under favorable conditions manganese can have an effective ferromagnetic moment of the order of 3.41,2 or even 4.0 compared with a moment of 2.2 Bohr magnetons for iron. The incidence of ferromagnetism is believed to be controlled by the degree of atomic separation.4,5 This is consistent with the fact that the atomic separation, when considered in terms of the ratio of the atomic diameter R to the diameter r of the 3d-shell, is larger in the ferromagnetic metals. The values of R/r calculated by Slater,' for metals of the iron group are given in Table I, and Slater has suggested that the critical ratio of R/r is 1.5. Consideration of the criterion of atomic separation alone would suggest that there are three classes of possible ferromagnetic manganese alloys: 1— Ordered structures, of either solution or compound types, such that manganese atoms are not near neighbors; 2—Structures in which the separation of near-neighbor manganese atoms is sufficiently increased by the presence of suitable solute atoms; and 3—Dilute solutions of manganese. Typical ferro- magnetic alloys of types 1 and 2 are the Heusler alloys and Mn4N, respectively. There are no recognized ferromagnetic alloys of type 3. In view of the proximity of the ratio R/r for manganese to the critical ratio of 1.5, the present work was concentrated on manganese-rich alloys rather than on ferromagnetic alloys of low manganese content, several examples of which are already known. Calculation of the distance of closest approach of manganese atoms in each of its allotropic forms, Table 11, indicates that the high temperature ? phase provides the most suitable basis for ferromagnetic alloys of high manganese content. However the high temperature forms of pure manganese cannot be retained on quenching, although a face-centered-tetragonal form apparently can be produced by electrodeposition. Since the critical separation which must be exceeded in order to obtain ferromagnetism is dependent upon the number of electrons in the d-shell, no exact critical value of R/r can be assumed. Not only will this separation vary from one pure metal to another, but it will also vary with the valency of the given type of atom when it is in an alloy. Raynor8 has shown that metals of the iron group probably

Jan 1, 1955