Search Documents

By Becerra J. O

HYL developed a direct reduction process (DR) that does not require a reformer; it is called self-reforming process. Typically, direct reduction processes based on natural gas utilise a reformer unit to transform the natural gas into reducing agents (hydrogen and carbon monoxide). The reforming reactions are: CH4+H20-?3H2+CO CH4 + CO2 - 2H2 + 2CO These reforming units require a catalyst agent to promote the kinetics of the reforming reactions. The catalyst for these reactions is typically a metallic element such as nickel in a ceramic matrix; iron is also an excellent catalyst for the reforming reactions.

Jan 1, 1999

By Tang Chaobo

Employing manganese carbonate ore and zinc oxide dust as material, Mn-Zn compound oxide powder for soft magnetic ferrite was prepared by a serial methods, as follows: leaching by using sulfuric acid, removing aluminium and silicon by neutralization and flocculation method, using ammonium bicarbonate to co-precipitating Mn and Zn, calcinations and washing to removing impurity content. The optimal technical condition was obtained by experiments. The difficulty of removing impurity such as Si, Al, Ca, Mg, from leaching solution was solved. The impurity content in the production meets with the preparation standard of high quality soft magnetic ferrite. The compound oxide powder obtained in the experiment was made into lower power loss magnetic ferrite, the quality of magnetic ferrite meet the standard of PC40 which was established by TDK corporation.

Jan 1, 2006

By Jean Habimana

The Detroit Upper Rouge Tunnel CSO Control Project will capture and store up to 201 MG of combined sewer overflow from 28 outfalls in Detroit, Dearborn Heights and Redford Township during wet-weather events. The history of rock tunneling in the area is associated with high groundwater inflows, artesian pressure, and hazardous and combustible gases. This paper presents the geotechnical considerations for designing the 11.28-km (7-mile) long, 9.14 m (30-ft) finished diameter tunnel and its associated adits, chambers and shafts, including the discussions of geotechnical investigations, rock mass characterization, estimated groundwater infiltration during construction, and the selections of excavation methods and lining system based on anticipated ground behavior to be encountered.

Jan 1, 2008

By James E. Adler, Timothy C. Richmond

The Stillwater District is located in south central Montana approximately 75 miles southwest of Billings, the state's largest city. It lies along the northeast front of the Beartooth Mountains and is within the boundaries of the Custer and Galatin National Forests. The first white visitors in the district were the early trappers, who were soon followed by the prospectors. These early prospectors were drawn to the area by gold and silver discoveries at Cooke City in 1870 as well as by the large gossan formation in Verdigris Creek near the west bank of the Stillwater River and by several scattered smaller gossan exposures throughout the area. The first patented mining claims were recorded in September, 1886.

Jan 3, 1974

By Roger A. Kauffman, Dean Van Dyk

Feldspar is the earth's most abundant mineral group. The feldspars are aluminum silicate minerals belonging to the tectosilicate class. Feldspars are the most widespread of any mineral group and are estimated to constitute 60% of the earth's crust. They make up a large percentage of the exposed rocks as well as soils, clays, and other unconsolidated sediments. Feldspars are widely used in the glass and ceramic industry and are principal components in rock classification schemes. Feldspar minerals and their production are important contributors to the domestic and world economies and standard of living. In 1990, the United States produced 630 kt of feldspar minerals, and world production was estimated to be more than 5 Mt. Feldspar mineral production in the United States has a long and interesting history (Feitler, 1967, Rogers Jr. et al., 1983). The first commercial production in the United States occurred in about 1825 and came from pegmatite bodies located in Connecticut, where feldspar was mined, hand sorted, and shipped to England. Feldspar production grew during the 19th and 20th centuries with important developments in production location, integrated mine and processing facilities, and the development of the flotation process for feldspar by the US Bureau of Mines and the feldspar industry. The first commercial feldspar flotation plant began operations-in Kona, NC, in 1946, some six years after this process had been developed. In 1990, the domestic feldspar industry consisted of 12 operating companies with mines and processing plants located throughout the United States (see Table 1). During the last 25 years, the domestic feldspar industry has been dynamic, marked by new plant construction and capacity expansion at older plants. The industry has also seen plant closures, changes in ownership of existing operations, the consolidation of the Canadian nepheline syenite industry, and the increase of imported feldspar products. The industry has been affected by contractions in its major end-use markets brought about by economic cycles, product substitution, and environmental effects, such as recycling, land-use controversy, and air and water pollution. Despite problems, the industry remains mature and highly competitive. GEOLOGY Mineralogy The common feldspar group of minerals form a single crystalline phase or solid solution series of minerals. Fig. 1 is a ternary phase diagram that shows the feldspar mineralogy-KAlSi,O8, NaAlSi3O8, and CaAl2Si2O8. The end-member compositions are also referred to as potassium, sodium, and calcium feldspar. The feldspars whose chemistry ranges between the potassium and sodium end-members are known as alkali feldspars, while those between the sodium and calcium end-members are plagioclase feldspars. These feldspar groups can be further subdivided based on structural and compositional features within the alkali or plagioclase feldspar series. The distinction between and the proportion of members of the two feldspar groups are important to the classification of igneous rocks (Deer et al., 1966). Perthites are the exsolution product of an initially homogeneous potassium-sodium feldspar solid solution which forms (in an environment of decreasing temperature) a heterogeneous intergrowth of sodium-rich feldspar lamellae in a host crystal of potassium feldspar. Antiperthites are exsolution products in which the host mineral is sodium-rich plagioclase feldspar and the intergrowths are potassium-rich feldspar.

Jan 1, 1994

By F. M. Makarinsky

"SynopsisThe Kanichee open pit mine and milling complex is situated approximately four air miles north-west of Ternagami, Northern Ontario, in Strathy Township. Mining and milling production commenced in January 1974.Milling throughput currently is at a rated capacity of 500 tons per day, seven days per week. A bulk nickel-copper sulphide concentrate is produced, and is trucked daily to the smelter at Falconbridge Nickel Mines Limited, Falconbridge, Ontario, some 120 road miles from Kanichee. Concentrate grades produced are in the order of 4.0% Ni and 8.0% Cu, with corresponding recoveries of 68-70% nickel and 86-90% copper. Stage additions of 100% guar-gurn solution reagent to the flotation cells for depression of talcose minerals, proved to be the major break-through for optimizing metallurgical performance.2. HistoryThe present Kanichee Mining property is known to old-timers in the Temagami area as the former Cuniptau Mine. Several attempts were made in the mid '30's and 40's to extract the ore at a profit, but each effort resulted in failure.In 1933-36, Cuniptau Mines Development Co. Limited, later called Cuniptau Mines Limited, sank a 245-foot vertical shaft and completed 2,200 feet of lateral work on the 100-140 and the 225 foot levels. Fifteen tons of ore were sent for testwork to the Mines Branch, Ottawa, Ontario.Cuniptau Mines Limited, in 1936, milled some 3,000 tons, and the resulting concentrate was put through a pilot smelter situated on the present mine site. Metallurgically, the smelting results were not encouraging, primarily due to the high melting point of the talcose minerals in the concentrate. From the period 1937-48, minor exploration work was done by Ontario Mining Corporation, Ontario Nickel Mines Limited, and Trebor Mines Limited. During the period 1948-49, 128 diamond drill holes, totalling 40,900 feet were evaluated by Trebor Mines Limited. In 1961, the name was changed to Ajax Minerals Limited, during 1968, five diamond drill holes were sunk, totalling 1,700 feet. Since that period the property has remained idle."

Jan 1, 1975

By Fiona Campbell

"Modern history is full of breakthroughs in technology, all striving to increase productivity and efficiency. What are the elements that should be taken into consideration in the design and implementation of modern automation systems in a control room? Both industry and international standards are now demanding that Human Factors be considered as part of the design of control rooms to maximize efficiency and minimize the potential of human error which can lead to downtime and a loss of profit as a result of interruptions in production. As the current workforce ages and the younger generation matures, this is also becoming a key element when planning a control room. New standards are helping to address some of these challenges that are facing the mining industry today. With an increased focus on the operator, an intelligent and ergonomic workspace can both mitigate risk and optimize production. Optimization is money. We will examine how to analyze and implement innovative control room planning to maximize mineral processing production and minimize risks that can impact overall production and profit.INTRODUCTIONIn this day and age, optimization of production in an industrial environment is becoming more and more of a challenge. With ever changing technology as well as other external factors, this can be especially daunting. There are several key elements that may not be immediately obvious when planning a control room design or renovation, most notably the role of the human in this environment. Fatigue, stress, distraction, reaction times and situational awareness are all critical in a 24/7 environment. With the growing need to include human factors when considering and designing an optimal work and production environment, it is becoming even more important to design a control room that can address as many of today’s challenges as possible.The standard definition of the word “optimization” is “an act, process or methodology of making something (as a design, system, or decision) as fully perfect, functional or effective as possible.” (www.merriam-webster.com). If we apply this to business, what it really means is finding the most cost effective way to achieve the highest level of performance while considering constraints, both external and internal, by maximizing the desired factors and minimizing undesired ones. Sometimes, however, we can get caught up in the day to day processes, without taking a moment to step back and objectively review what it is we need to achieve, and more importantly, the steps that can facilitate our success."

Jan 1, 2016

Production of crude oil in Bahrein Island during 1938 reached the new high of 8,297,998 bbl., an increase of 535,734 bbl, over the 1937 production of 7,762,264 bbl. The monthly average during 1938 was 691,500 bbl. and the daily average 22,734 barrels. To the close of December 1938, a total of 52 producing wells have been drilled. During the year 13 producing wells were completed and 11 wells were drilling or partly completed as of Dec. 31, 1938. The total footage drilled as of Dec. 31, 1938, amounted to 165,339 ft., of which 60,739 ft. was drilled during 1938. The production from the main pay comes from a depth of approximately 2200 ft. and the gravity of the oil is 33" A.P.I.

Jan 1, 1939

Production of crude oil in Bahrein Island during 1938 reached the new high of 8,297,998 bbl., an increase of 535,734 bbl, over the 1937 production of 7,762,264 bbl. The monthly average during 1938 was 691,500 bbl. and the daily average 22,734 barrels. To the close of December 1938, a total of 52 producing wells have been drilled. During the year 13 producing wells were completed and 11 wells were drilling or partly completed as of Dec. 31, 1938. The total footage drilled as of Dec. 31, 1938, amounted to 165,339 ft., of which 60,739 ft. was drilled during 1938. The production from the main pay comes from a depth of approximately 2200 ft. and the gravity of the oil is 33" A.P.I.

Jan 1, 1939

By Forrest T. Moyer

Injury experience in the coal-mining industry was worse in 1965 as both the frequency and severity rates of injuries increased 2 and 6 percent, respectively, over comparable data for 1966 (tables 1-8). The retrogression in the safety record during; 1965 resulted frog the less favorable record at bituminous-coal mines, which more than offset the improved injury experience at anthracite mines. The 259 fatal and 11,138 nonfatal injuries occurred at a rate of 45.77 per million man-hours of exposure and resulted in a severity rate of 8,960 days lost per million man-hours. Although the number of fatalities was the second lowest annual total in the recorded history, it was 17 higher than in 1964. At anthracite operations the total of 6 fatalities in 1965 was the lowest annual figure in statistical history. The annual numbers of nonfatal injuries at ill coal mines and the resulting rates of occurrence have varied little in the past 5 years (table 1). The total days lost from all injuries rose from 2.1.3 million in 19b4 to 2.23 million in 1965 (table 5). Fatal and permanent total injuries, with a standard time charge of 6,000 days each, accounted for 1,650,000 days; Permanent partial injuries, 191,932 clays; and temporary total disabilities, 383,911 days. The severity rate for fatal injuries was 6,241, 8 percent higher than in 1964, and the nonfatal severity rate of 2,718 days lost per million man-hours was 2 percent higher than in the preceding year. The average severity of permanent partial injuries ire; 730, or 48 days fewer per injury than in 1964. The average days lost for each temporary total injury was 36 days in each year.

Jan 1, 1968

By C P. de Jager, J J. Taljaard

Over the past 75 years, the mining of platinum has predominantly focused on the Merensky Reef horizon in the western Bushveld region of the Bushveld Igneous Complex (BIC) of South Africa (Figure 1). The orebody is relatively flat dipping at 10¦ to 25¦, narrow tabular in shape and has been mined to a maximum depth of some 1600 m within Anglo Platinum. This has resulted in the installation of up to four generations of shaft systems as mining progressed into reserves at greater depth. In recent years, with the improvement in processing technology and improved economics, in particular with the improved price of palladium, the mining of the UG2 Chromitite Reef is proving economically viable. The UG2 Chromitite Reef occurs below the Merensky Reef in the succession and the normal separation varies from 15 m to 400 m, with the largest separation between the reefs occurring in the eastern region of the BIC. The UG2 Chromitite Reef horizon is now being accessed from existing Merensky mining infrastructure by cross-cutting back through the stratigraphy where appropriate, or by establishing new decline cluster systems from surface, along the extensive strike length of the various mining properties. These declines are generally established utilising mechanised mining techniques. This paper gives an overview of the techno-economic approaches considered and evaluated for the selection of the optimum mining and shaft systems. More specifically, the paper reviews the design parameters used, techno-economics, conveyor versus haul alternatives, logistics simulations, capital costs, system performance, time to market or ramp-up success, important system differences and lessons learnt.

Jan 1, 2005

By Guy R. Johnson

Like many other similar plants the ore-washer of the Longdale Iron Company has been a growth of years. In its principal features there is probably nothing new, as the type is that of the well-known " log-washer." Some of its minor details may, however, be of interest to those members who have to deal with the washing of large quantities of brown iron-ores, the principal gangue of which is clay. * Until 1883, the ore at Longdale, being of unusual purity, needed no washing, and was charged to the furnaces as it came from the mines—both lump and fine—the only attempt at cleaning being the' picking over a screen of 1½-inch iron bars, 3½ inches from center to center, set in the top of the bins through which the cars for the furnaces were loaded." In 1883 it was no longer possible to win the ore by open cuts, and regular underground work became necessary. It was very

Jan 1, 1895

By Charles Rich, Robert Munson, Leonard Obert

Improved methods of predicting the caving characteristics of ore bodies is discussed. Experiments were conducted at Climax mine, Climax, Colo., on varied rock compositions. The cavability of adjacent areas, as well as seismic energy absorption proved to be good factors in determining cavability. Seismic velocity, core recovery, and rock quality designation (RQD) were found to be not as reliable.

Jan 1, 1977

By Jehan Rondot

Les bancs de quartzite inhabituellement purs et epais decouverts lors de la cartographie geologique de la region de Charlevoix sont maintenant entres au stade de !'exploitation et se revelent etre une richesse naturelle durable pour cette region. Les etudes stratigraphiques effectuees dans cette partie (Quebecia) du bouclier canadien indiquent que la succession: lo. complexe a amphibolite et leptynite a la base, 2o. quartzite et gneiss a sillimanite, muscovite et gneiss calcosilicate et conglomeratique au sommet est constante sur de grandes distances (de Charlevoix a la Basse Cote Nord) et represente une sedimentation continentale et de plateforme, peu epaisse, du proterozotque inferieur. La purete et la grande epaisseur du quartzite s'expliqueraient par un processus de sedimentation continentale complexe ou se succedent climat tropical-humide et glaciaire-aride et transport fluviatile et eolien. Parmi la multitude de depots de quartzite qui existent dans le monde, peu sont de qualite superieure. Or, de par sa composition chimique, le quartzite de La Galette se compare avantageusement a ceux des meilleurs gisements des Etats-U ni s, de l'Europe de l'Ouest et de I' Afrique du Sud. D'acces facile pour l'exploitation, les gisements ne sont qu'a une quarantaine de kilometres de Baie Saint-Paul ou de La Malbaie, sur le SaintLaurent. L'utilisation en metallurgie du quartzite de La Galette comprend la production de silicium, de ferro-silicium et d'autres alliages de silicium . La composition du quartzite est en outre appropriee pour la production de carbure de silicium et de silicate de sodium. Les fines peuvent etre utilisees pour la fabrication du verre et comme matiere de charge.

Jan 1, 1984

By Stanley Dempsey

Mine developers commonly undertake projects that require more funds than they can invest themselves. From that point until they are able to complete a "bankable" feasibility study, they require access to venture capital. In the United States, most venture capital has been provided to the small mining segment of the industry through tax advantaged limited partnerships. Recent changes in Federal tax law makes other forms of financing competitive, and the use of corporations and private and public offerings of shares may soon become more popular ways of securing venture capital. A number of new financial services firms have entered the mining finance business in recent years. They provide mine developers with access to venture capital.

Jan 1, 1987

By Faan Bornman

"Reeves and Platt1 stated that dense medium separation is one of the most complex unit processes in mineral processing today particularly if cyclones are used. It is also the most efficient gravity concentrating process available to process engineers. The complexity of the process and large number of design and operating variables means that the process has largely remained more an art than a science. Dense medium separation is well established in the diamond, coal and iron ore industries but is gaining popularity as a pre-concentration step in other industries. The maintenance issues are addressed that will affect the efficiency of the operation.INTRODUCTION The purpose of the dense medium separation (DMS) process is to separate the valuable material from the waste based on gravity differences. However, the specific gravity difference between the two fractions must be large enough to achieve high efficiencies. Heavy particles sink through the dense liquid and light particles float. DMS is also used for the pre-concentration of minerals before further downstream processes like communition, in order to minimise the treatment costs. Examples are the pre-concentration of diamond ores or metalliferous ores like nickel, copper and cobalt. Dense medium separation is also used to upgrade the material to meet different market specifications, for example in coal and iron ore applications. A typical dense medium separation process for a diamond application is shown in Figure 1."

Jan 1, 2014

By Eric M. Klein

As part of the Woodrow Wilson Replacement Bridge project several damaged wetland and environmental areas were to be mitigated. One of the mitigation projects consisted of constructing a Denil fish ladder around Peirce Mill Dam in Rock Creek National Park, Washington, D.C. The dam is a historic structure operated by the National Park Service. The fish ladder is located between the east abutment of the dam and Beach Drive, a major collector road. Construction of the fish ladder required removal of a portion of the east abutment and an excavation that extended about 22-ft below the pavement of Beach Ave. It was not possible to close Beach Drive except for very brief intervals or at night; therefore, a support of excavation system that would minimize disruption to the public was required. The high groundwater required that the groundwater be cut off prior to excavation; the random rubble and soil fill, and shallow but erratic rock surface precluded driving sheet piling. A jet grout system was selected because the grout probe could penetrate the rubble fill, stabilize a variety of soil conditions, and cut off the ground water prior to excavation. It was not possible to construct a stable wall without tiebacks or soil nails. Given the schedule and tight working conditions it was decided that soil nails through the jet grout wall facing would be the most cost effective method, as it did not reduce the working space as rakers would and would be more cost effective than prestressed tiebacks.

Jan 1, 2006

By P. D. R. Maltby

"The Canadian Institute of Mining and Metallurgy has undertaken to host the XIV International Mineral Processing Congress to be held in Toronto at the Royal York Hotel from October 10 to 16, 1982. The theme of the Congress will be ""Worldwide Industrial Application of Mineral Processing Technology."" The program will include 10 sessions and numerous field trips to the different mining areas of Canada.For prospective authors, the preliminary program includes sessions on,1. Flotation - plant practice, equipment design, simulation, control and economics.2. Comminution - plant practice, equipment, design, simulation, control, wear, energy consideration and economics.3. Round table seminar on large grinding mills.4. Round table seminar on modern and future plant design.5. Mineral processes to recover precious metals.6. Mineral processes to recover energy minerals (coal, uranium).7. Mineral processes to recover industrial minerals.8. Round table seminar on the environment and ecology and how the different countries cope with associated problems.9. Materials handling with an emphasis on agglomeration techniques ereconentration methods, solid-liquid separation.10. Open session to deal with topic emerging from general demand."

Jan 1, 1980

By G. S. Jenkins

The statistics set forth by Professor Mitchell in a proceding paper very carefully brought out the points that indicate that a marked amount of consideration must be given to" the haulage problem to adapt it to local conditions as encountered. Professor Mitchell's paper showed a spread of from 10 tons per man to 50 tons per man on the production crews, which spread can be recognized as entirely too large when one considers that the product is being sold at a price within very close limits. While a portion of this spread may be explained by different methods in cost accounting as to what employees are applicable to the production crew, it cannot all be blamed on an accounting method. A good portion must be explained by the improper application of equipment to the needs incurred by the local conditions. It is in an endeavor to go into this phase that this paper is given. It will be necessary to qualify the points covered in order to keep the subject from becoming too wide in scope. Along this line, conditions will be only those involved in bituminous coal mine practices and only the haulage of coal that is loaded with mobile loading machines in seams 4 ft thick and better. Haulage Methods Employed The Consolidated Coal Co. (Illinois) has been operating on a modernized basis for about 20 yr. By modernized we mean the loading of coal with mobile loading equipment. In review of haulage methods, it must be remembered that the main line electric haulage locomotive has been in service for some 40 or jo years. To augment this main line haulage, the mule did a quite satisfactory job during hand-loading days, but was later replaced by the gathering locomotive, either battery or cable-reel operated. This type of haulage was the method in common use at the time the mechanical loading of coal became of major importance and the success or failure of loading machine installations may be largely accredited to haulage facilities in the early days; that is, in the period around 1930. The Consolidated Coal Co. had its struggle with this problem beginning in about 1927 or 1928. We were somewhat fortunate in that we were already using gathering locomotives powered by storage batteries at the time we introduced mechanical loading. This meant that we did not have to spend as much time training motormen and trip riders as many mines did that utilized only mules for their secondary haulage. This was all advantage, and our efforts could be focused on ways and means of providing adequate car service to the loading machine. Like most operations, we endeavored to gear the car service to the capacity of the machine, with a large crew endeavoring to load the maximum tonnage that the machine would handle. Toward that end our first move was to install switches

Jan 1, 1949

By Ted Klemetti

Roof deterioration in weak moisture-sensitive rock leads to roof falls in coal mines. An observation site was set up in intake air at an underground coal mine in central Ohio to evaluate the time-dependent deterioration of moisture-sensitive roof rock. By periodically collecting and weighing the rock falling from the roof, the National Institute for Occupational Safety and Health (NIOSH) was able to quantify the deterioration of the moisture-sensitive shale roof. The measurements showed that more roof rock is falling in the dry winter months. Movements in an intersection were monitored in order to determine if deformation correlated with seasonal changes in temperature and humidity. The rate of intersection roof-to-floor convergence was found to be cyclical and related to seasonal changes, with more convergence during the months of April through September. At the study site intersection, the roof beam did not show deflection indicating movement most likely due to mine floor deformation. The bolt load also increased in the warmer months before shedding load, possibly due to rock failure. Temperature and relative humidity sensors, placed in holes in the roof show that mine air does not mix with the air in the holes. Consistent saturation levels of relative humidity were measured in the holes and it appears that high levels of moisture may have migrated into the bolt holes from roof shales. A roof sealant applied to a portion of the test roof appears to be preserving the roof and reducing the amount of rock fall into the entry, while the screened area virtually eliminated rock falling from the roof.

Jan 1, 2009