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By J. Utt

Recent developments in circulating fluidized bed (CFB) once-through supercritical technology (OTSC) have enabled this technology to be offered as a utility-scale alternative competing head-to-head with pulverized fuel (PF) OTSC offerings. One clear example is the CFB supercritical unit at the Lagisza Power Plant in Poland, owned by PoludniowyKoncernEnergetyczny SA (PKE). This unit has now been in commercial operation for three full years, exhibiting very good performance, and has validated Foster Wheeler?s performance model at this utility scale as well as for units in the 600 MWe and 800 MWe size ranges offering net efficiency of ~43 per cent (LHV basis). This operating unit has also proven the use of the world?s first FW/BENSON? vertical-tube OTSC low mass flux technology. Since the Lagisza original international tender specified OTSC PF technology, it is important to note that the alternative selection of CFB OTSC technology over conventional PF technology is of historic significance, not only for the validation of the CFB supercritical platform as a viable alternative to conventional PF technology, but it also positions the CFB OTSC with fuel flexibility for offering of sizes up to and including 800 MWe units. This paper explores the differences between CFB OTSC technology and standard PF OTSC in utility power generation. Selection criteria, fuel burning range in both technologies, and other selection drivers are discussed. Economic analysis of both technologies, based on existing cases, is also provided. Also discussed are the technical advantages and uses of each technology. Foster Wheeler has recently been awarded a contract for four units of CFB OTSC technology, which utilizes a 2 on 1 configuration of two 550 MWe CFB OTSC boilers on two single 1000 MWe turbines. Essentially this provides a fuel-flexible low-emissions alternative to a 2 × 1000 MWe solid fuel power block.

Jan 1, 2012

By J. Utt

Recent developments in circulating fluidized bed (CFB) once-through supercritical technology (OTSC) have enabled this technology to be offered as a utility-scale alternative competing head-to-head with pulverized fuel (PF) OTSC offerings. One clear example is the CFB supercritical unit at the Lagisza Power Plant in Poland, owned by PoludniowyKoncernEnergetyczny SA (PKE). This unit has now been in commercial operation for three full years, exhibiting very good performance, and has validated Foster Wheeler's performance model at this utility scale as well as for units in the 600 MWe and 800 MWe size ranges offering net efficiency of -43 per cent (LHV basis). This operating unit has also proven the use of the world's first FW/BENSONTM vertical-tube OTSC low mass flux technology. Since the Lagisza original international tender specified OTSC PF technology, it is important to note that the alternative selection of CFB OTSC technology over conventional PF technology is of historic significance, not only for the validation of the CFB supercritical platform as a viable alternative to conventional PF technology, but it also positions the CFB OTSC with fuel flexibility for offering of sizes up to and including 800 MWe units. This paper explores the differences between CFB OTSC technology and standard PF OTSC in utility power generation. Selection criteria, fuel burning range in both technologies, and other selection drivers are discussed. Economic analysis of both technologies, based on existing cases, is also provided. Also discussed are the technical advantages and uses of each technology. Foster Wheeler has recently been awarded a contract for four units of CFB OTSC technology, which utilizes a 2 on 1 configuration of two 550 MWe CFB OTSC boilers on two single 1000 MWe turbines. Essentially this provides a fuel-flexible low-emissions alternative to a 2 x 1000 MWe solid fuel power block.

Jan 1, 2012

These proceedings consist of an overview of the underground metal and nonmetal mina fire protection research currently being conducted by the Bureau of Mines. The following papers address the areas of prompt, reliable fire detection, fire planning and warning, fire suppression, and personnel protection. Selected topics are included here that cover fire protection systems for shafts, underground fueling areas, and mobile underground mining equipment; spontaneous combustion, improved stench, and product-of-combustion fire warning systems; computer-aided ventilation modeling; fire doors; and an investigation of fire hazards in mine timbers. The projects described provide a current documentation of problems being addressed.

Jan 1, 1981

By Thomas L. Ochs

The Bureau of Mines is investigating the fundamental behavior of electric arcs in electric furnace operations. The electric arc is a poorly understood phenomenon. If the arc in a steelmaking furnace can be more carefully controlled, it should be possible to increase heat transfer to the melt, reducing both electrical and acoustical noise. As a first step toward a better understanding of the are, voltage and current signals from operating furnaces were analyzed. The results of the initial analysis show that instrumentation used in monitoring and controlling furnaces, such as meters and strip-chart recorders, gives incomplete or erroneous information to the operator and therefore leads to less than optimal control. Advanced instrumentation and analysis techniques, such as the waveform analysis used in these investigations, can improve the understanding of operation and the control of electric furnaces. This report describes the instrumentation and the numerical analysis methods used and compares these methods with standard metering and recording techniques.

Jan 1, 1986

By James A. Wasson

Because of the danger to life and property in a coal mine if an oil or natural gas well should be accidentally intersected during mining operations, certain precautionary measures should be carried out prior to entering previously unmined areas. The locations of all wells both at the surface and at the depth of the coalbed should be accurately determined. The condition of the well should be learned from surface observations, and more importantly, from subsurface examination by geophysical logging devices where possible. It is also desirable to learn the physical properties of the hydrocarbon-bearing rock formation and the hydrocarbon fluids. The major hazard presented by oil or natural gas wells to mining operations is that of explosion and fire due to the rapid release of gas into the mine atmosphere. Wellbore pressure, the principal index of danger, should be determined by one or more of the methods described and by a service company such as those listed in the appendix. Because of high pressures involved and the consequent hazard, much emphasis has been placed on underground storage of natural gas in areas containing minable coalbeds. Maps are shown of the principal coal producing areas and the locations of currently active gas storage reservoirs. A checklist has been included of factors to be considered when mining coal in an area where oil or gas wells exist.

Jan 1, 1973

By Richard A. Winters

There are no producing or developing mines or active mining claims in the Deschutes Canyon RARE II study area. Only two prospects were found; they have no identified potential for mineral resources. Thin diatomite deposits occur in the Pliocene Madras Formation. Development of sand and gravel deposits in the area could not favorably compete with similar deposits in the surrounding area which are closer to points of use. By mid-1982, active oil and gas lease applications covered about 25 percent of the area, a reduction from nearly 100 percent in early 1981. No holes were drilled for oil and gas exploration. INTRODUCTION Personnel of the Bureau of Mines, Western Field Operations Center conducted a mineral investigation of the Deschutes Canyon RARE II area during the summer of 1982. The area, about 10 mi (16 km) southwest of Madras, Oregon, covers 10,890 acres (4,407 ha) in the Crooked River National Grasslands (fig. 1). The Deschutes River has incised a deep canyon into the north sloping elevated lava plain near the transitional boundary of the High Lava Plains and the Deschutes-Umatilla Plateau geomorphic divisions (Baldwin, 1964, p. 20).

Jan 1, 1983

By F. P. Haver

Primary lead is produced in the United States by the pyrometallurgical smelting of lead sulfide (galena, PbS) concentrates, which poses sulfur dioxide and lead air pollution control problems. The Federal Bureau of Mines has investigated an alternative hydrometallurgy procedure that does not generate gaseous sulfur oxides and diminishes the potential for the escape of lead into the atmosphere. The procedure involves leaching galena flotation concentrates with ferric chloride (FeC13) solution to obtain lead chloride (PbC12) and elemental sulfur as expressed by the following chemical reaction: PbS + 2FeC13 ? PbC12 + 2FeCl2 + S°. At 100° C, over 99 pct of the PbS in the concentrate is converted to PbCl2 in less than 15 min. The leach solution, composed of brine (NaCl) containing slightly more than the theoretical required amount of FeC13, dissolves the PbC12 as it is formed, leaving a residue of elemental sulfur plus gangue. High-purity PbC12 (>99.9 pct) crystallizes from the leach filtrate on cooling and is electrolyzed in a low-temperature, fused-salt cell to obtain corroding-grade metal (>99.94 pct Pb). Spent leach solution (FeC12) is regenerated for further use by reaction with the chlorine obtained in the electrolysis of lead chloride. Other values, such as Ag, Cu, Zn, and S°, are recovered by additional treatment of either the leach solution or leach residue.

Jan 1, 1976

By Syd S. Peng

Mountaintop removal (MTR) mining started in West Virginia nearly 30 years ago. This surface mining method can extract multiple coal seams as thin as a few inches in whole and minimum rock dilution in very steep mountainous terrain. MTR is highly efficient, even if coal seams are in close proximity and small in a real extent. Consequently, MTR has been widely used in the Central Appalachian coalfield (mainly Kentucky, Tennessee, Virginia and West Virginia) with great success. In that respect, there has been no demand for research and little scientific research has been performed to investigate its impact on the surrounding area. During the past two years, however, the debate over MTR mining has grown quickly and has become very intense. This article describes chronologically issues raised by various parties, legal actions, impacts on mining permit applications and research projects developed to address the issues.

Jan 1, 2000

Edward Keller, Baltimore, Md. (communication to the Secretary): When, at the New Pork meeting, February, 1899, Mr. Douglas gave an abstract of his highly interesting paper on the Copper Queen mine, he invited the members of the Institute, in his usual progressive spirit, to make a full scientific investigation of the region of that mine during the prospective excursion to Bisbee, Arizona. I volunteered to examine some of the metallurgical processes and products of the works, and obtained from Mr. Douglas a valuable series of samples. Upon the issue of his paper, however, I found that he had already a considerable volume of analyses of those products, and that little was left for me to do in that respect, except to duplicate his results, the importance of which work would not have been commensurate to the time and labor involved. I selected, therefore, only some points which he had not made entirely clear, or concerning which I was skeptical. The details of most of my work will appear in a future paper. From Mr. Douglas's figures I have calculated the values for the elimination of impurities in the so-called Leghorn converter, introduced by him at the Copper Queen works, and have found them to be as follows: Percentage of Elimination of Impurities in Pour Blows of a Converter. No of ' Selenium Sulph'r Iron. Zinc. I Nickel. Lead. Antimony Arsenic. and Blow- ! Tellurium .. 1.......... 99.4 99.6 88.0 92.6 94.4 81.6 83.8 40.3 2.......... 99.0 99.6 98.1 92.5 96.8 71.9 76.6 38.1 3.......... 98.8 99.5 93.5 91.4 96.3 63.8 80.6 25.3 4.......... 99.8 99.5 95.8 95.8 97.5 65.3 76.9 36.3 Average 99.2 99.6 93.8 93.1 . 96.2 70.6 ! 79.5 35.0

Jan 1, 1900

Technical Challenges in the Flotation of Molybdenite from Porphyry Copper Ores

Sep 13, 2010

By W. R. Leeder

"The Quintette coal property lies in the Rocky Mountain foothills of northeastern British Columbia (see Figure 1). Quintette and the adjacent Bullmoose property of Teck Corporation are soon to become the first commercial coal mines in the Peace River Coal Field, which is estir1ated to contain 10 billion tonnes of metallurgical coal reserves.Denison Mines Limited acquired the original Quintette coal licenses in 1969 and 1970. Exploration began soon after and the first feasibility study was conducted in 1975. Denison devoted the following six years to extensive planning and feasibility studies of the project. During this period, the provincial and federal governments also undertook studies to assess infrastructure requirements and economic viability of development in this part of the province. Many of the proposed mine sites such as Bullmoose and Quintette were at least 100 to 150 kilometres from the towns of Chetwynd and Dawson Creek, the nearest centres serviced by good highways and a railroad, and a complete network of services would have to be provided if such mines were to be developed. The overall project became known as the North East Coal Development.Concurrently with the feasibility studies, numerous technical and sales missions to Japan were made by representatives of Canadian industry and government, culminating in January 1981 with agreements for Quintette Coal Limited and Teck Corporation to supply a total of 115 million tonnes 8 million tonnes per year for 15 years of primarily metallurgical coal to the Japanese Steel Industry."

Jan 1, 1983

Further discussion at the North of England Institute of Mining and Mechanical Engineers' general meeting held in Newcastle-upon-Tyne, 3rd June 1916, on the paper published in Trans. I.Min.E., vol.L, 1915, p.179, consisted of the author's written response to Mr. Hare's comments at the April meeting

Dec 1, 1916

By Keith Schaeffer

This paper presents a history of the planning, engineering and construction completed for the railroad tunnel crossing part of the West Elizabeth Avenue Storm Drainage Project, undertaken to relieve flooding within the West Elizabeth Avenue area in Linden, NJ. The Railroad Crossing Contract is part of the larger Linden Drainage Improvements Project consisting of a new gravity storm sewer system. The improvements are required to provide additional storm drainage for the City of Linden and the Merck Pharmaceuticals manufacturing facilities in the City of Linden.

Jan 1, 2008

By Charles H. Greene

This paper will describe briefly the steps taken in the development of a Central Florida phosphate ore deposit from acquisition to mining. Further, the design and early operation of the mining and beneficiation facilities will be depicted. During the 1950's, with confidence in the continually increasing requirement for phosphate fertilizer materials essential for producing food, I'. R. Grace & Cc acquired the Hookers Prairie tract containing approximately 45 million metric tons o. (50 million short ton~ of potential phosphate rock product. In 1973, at a point when the Grace captive need for rock was being greatly enlarged by a planned doubling of its Bartow phosphate chemicals plant capacity, the decision was made to expand existing phosphate rock production by building a new mine and plant. The initial annual capacity was to be 2.3 million tons (2.5 million st); however, subsequent investigation pointed to a higher than estimated dragline operating factor 'and the forecast of annual capacity was set at 2.5 million tons (2.8 million st).

Jan 1, 1977

By Charles W. Carter, Alfred H. Bell

In 1943, Illinois produced 82,256,000 bbl. of oil, or 5.5 per cent of the total for the United States, and ranked sixth in the nation in oil production. This represents a decline of 23 per cent from 1942, when the total Illinois production was 106,ggo,o~~ bbl. and Illinois ranked fifth. The daily average production for 1943 was approximately 225,000 bbl. Daily averages by months were as follows: Jan......... 238,000 July......... 218,000 Feb......... 240,000 Aug......... 216,000 Mar......... 237,qoo Sept........ 220,ooo Apr......... 230,000 Oct......... 220,000 May....... 221,000 Nov......... 223,000 June......; . 222,000 Dec......... z18,ooo This shows that most of the decline during the year took place between March and May, and that for the last eight months of 1943 production has been essentially steady. This means that there has been enough production from new wells drilled to balance the natural decline of the Older wells. The trends of drilling and production are shown in Fig. I and Table 3.

Jan 1, 1944

By Alfred H. Bell, Charles W. Carter

In 1943, Illinois produced 82,256,000 bbl. of oil, or 5.5 per cent of the total for the United States, and ranked sixth in the nation in oil production. This represents a decline of 23 per cent from 1942, when the total Illinois production was 106,ggo,o~~ bbl. and Illinois ranked fifth. The daily average production for 1943 was approximately 225,000 bbl. Daily averages by months were as follows: Jan......... 238,000 July......... 218,000 Feb......... 240,000 Aug......... 216,000 Mar......... 237,qoo Sept........ 220,ooo Apr......... 230,000 Oct......... 220,000 May....... 221,000 Nov......... 223,000 June......; . 222,000 Dec......... z18,ooo This shows that most of the decline during the year took place between March and May, and that for the last eight months of 1943 production has been essentially steady. This means that there has been enough production from new wells drilled to balance the natural decline of the Older wells. The trends of drilling and production are shown in Fig. I and Table 3.

Jan 1, 1944

By Christopher J. Bise

INTRODUCTION The control of nuisance water in a mine is extremely important; left uncontrolled, nuisance water can have a severe effect on haulage, ventilation, production, and the health and safety of miners. To control water in mines, a four-step process is followed: (1) prevention, (2) collection, (3) transportation, and (4) treatment. This chapter will be devoted to the collection and transportation of mine water because prevention is usually dictated by pre-mining conditions and initial planning, while treatment is variable and highly site specific. A mine drainage system is nothing more than a collection of gathering points (sumps), machines that impart energy to the fluid (pumps), transportation ducts (pipes), and control devices (fittings, valves, etc.). A pump does not pull the fluid up the suction pipe; atmospheric or external pressure pushes the liquid up the suction pipe to the pump. All references in this chapter will be to centrifugal pumps, due to their popularity for mine drainage. PUMP CHARACTERISTIC CURVES The performance of a pump is plotted on a graph as an indication of its characteristic. To develop the data points, a test facility similar to that shown in Fig. 1 is established. The calibrated Venturi meter is used to measure quantity, the Bourdon gage measures pressure, and the wattmeter measures power input. Various discharge pressures are obtained by throttling with a gate valve in the discharge pipe. Quantity and power are measured at each of these pressure levels, giving the necessary data for plotting the characteristic curves. Fig. 2 shows a typical characteristic curve for a centrifugal pump. Notice that pressure is measured as so many feet of vertical water column above the outlet level, or head. Knowing the quantity (in gallons per minute), head (in feet), and power input (brake horsepower), the pump's efficiency can be plotted based upon the following relationship:

Jan 1, 1986

By X Tian, J Forster, A Olmsted, E R. Bobicki, M Goldbaum, D Boucher, C A. Pickles

As the global demand for metal values expands, it becomes increasingly important to create more sustainable mining operations. Consequently, considerable research and technology development is required to produce processes which are both more energy efficient and have a minimal environmental impact. One potential technology is the utilisation of microwave pre-treatment to reduce the energy requirements in comminution. Microwaves can preferentially heat the valuable mineral phases in an ore and the resulting differential thermal expansion leads to the formation of microfractures along the grain boundaries. As a result of the preferential heating, ore competency is reduced, mineral liberation is enhanced, a coarser grind size can be employed, and plant throughput can be increased. Furthermore, microwave pre-treatment can be combined with advanced ore sorting, to decrease the quantity of gangue material processed downstream and hence reduce tailings production. Previous studies on the microwave treatment of ores over the last 30 years have mainly been limited to low power bench-scale studies and there is a paucity of information on pilot and/or commercial scale studies. In the present research, the microwave heating behaviours of over 40 ores have been studied at the bench-scale. These results were used to generate a database, from which a unique classification system was developed. This system was used to rank the amenability of any given ore for microwave pre-treatment. This knowledge can be employed to predict the performance of the ores in the high-power pilot scale tests and thus can be used as a pre-screening tool. The effects of high-power microwave pre-treatment on grindability and liberation were reported. Additionally, the ore sorting potential was evaluated using a combination of X-ray transmission (XRT) and microwave infrared (MW/IR).

Aug 24, 2022

By J M. Santini, I C. A Streimann

Arsenic is a naturally occurring element in the environment and is toxic to biological systems. Arsenic can exist in the environment in the following redox states, arsenite (+3), arsenate (+5), arsine (-3) and elemental (0) (Oremland and Stolz, 2003). Arsenic is released into the environment by natural and anthropogenic activities such as rock weathering and ore mining, respectively. Such activities result in the release of the soluble inorganic arsenic oxyanions, arsenite and arsenate. The redox state of arsenic in the environment is influenced by a number of factors including, redox potential, pH and microorganisms (Irgolic et al, 1977; Genc-Fuhrman, Tjell and McConchie, 2004). Recently, the ability of microorganisms to influence the cycling of arsenic in the environment has attracted much attention. Microorganisms that can oxidise arsenite and reduce arsenate have been isolated and the mechanisms of arsenic metabolism are currently being investigated. The differences between arsenic resistance and arsenic metabolism are being revealed. The role of microorganisms in the release of arsenic into the environment is of particular importance with arsenic contamination of waters causing the death of millions of people worldwide, due to the consumption of contaminated water (Vasken Aposhian et al, 2003; Islam et al, 2004).

Jan 1, 2004

By W. P. Yant

A previous report of the Bureau of Mines dealt with the toxicity of dichlorodifluoromethane5, a new refrigerant that has a remarkably low toxicity. Continued research by the Prigidaire Corporation6 and toxicological experiments performed in the Laboratory of Applied Physiology of the University of Cincinnati7 revealed another organic fluoride, dichlorotetrafluoroethane, whose toxicity also appeared to be of a very low order and whose physical-and chemical properties make it suitable for refrigeration purposes. In addition to low toxicity, safety in its use is further enhanced by its physical properties, which permit the design of equipment that operates at comparatively low pressures and hence mitigates the dangers and problems of leakage. The investigation described in this report was performed by the Bureau of Mines at the request and with the cooperation of the Frigidaire Corporation.

Jan 1, 1932