Search Documents

By Chen Z, Dong H

This paper describes the autogenous carrier flotation of 0 - 20 ¦m ilmenite using 40 -- 80 }tm ilmenite as carrier. Investigation is made of the influence of main technological parameters on autogenous carrier flotation. The mechanism of autogenous carrier flotation is discussed using extended DLVO theory. The main conclusions are as follows: 1. the smaller the fine particles the more easily they adhere.to carriers; 2. the selectivity of autogenous carrier flotation depends on the selectivity of adsorption of collector. In the autogenous carrier flotation of ilmenite/plagioclase mixture assaying 15.35 per cent TiO2, a concentrate containing 47.17 per cent Ti02 can be obtained by primary separation with a recovery of 93.05 per cent. KEYWORDS: Autogenous carrier flotation, extended DLVO theory, ilmenite, styrylphosphonic acid.

Jan 1, 1993

By A. M. Elmahdy, T. Hirajima, M. Farahat

"Separation of molybdenite from chalcopyrite is mainly achieved through flotation technique to raise their grades up to 25% to be extracted in smelters. However, molybdenite recovery and grade obtained from this process is not satisfactory in most cases due to the natural hydrophobicity of both minerals. The influence of conventional heat treatment on pure chalcopyrite and molybdenite minerals was investigated. X-ray diffraction, TG-DTA and XPS techniques were applied before and after heat treatment. The results showed phase changes for both minerals. Magnetic separation experiments of single and mixture of both minerals at several magnetic intensities were made. For single mineral experiments, 100% molybdenite recovery was obtained at all experimental conditions as non-magnetic fraction whereas ca. 100% chalcopyrite recovery was achieved under certain conditions. In case of 1:1 binary mixture, 87% and 83% molybdenum and copper recoveries, respectively, were obtained. The increase in chalcopyrite magnetic recovery is related to the formation of more magnetic phases as confirmed by characterization techniques.The objective of this study is to increase the magnetism of chalcopyrite to make its separation from molybdenite by magnetic separation possible and to understand the mechanism behind it. These results indicate that it may be possible to upgrade molybdenite ores using heat treatment followed by magnetic separation to the required grade by smelters which is difficult to attain by froth flotation and the other techniques."

Jan 1, 2016

By Takashi Sasaoka, Hiroshi Takamoto, Kikuo Matsui, Hideki Shimada

"Indonesia is the second largest coal exporter to Japan. Almost all the coal is produced from open cut mines. However, a great deal of coal is left in the highwalls of the mined-out pits. The use of highwall mining systems has increasingly come into play in the U.S. and Australia, when overburden depth exceeds economical recovery in an open cut mine. However, the stability of the highwalls is always a major safety concern in such mining. This paper describes the characteristics of the highwall mining system and discusses the appropriate highwall mining system for use in Indonesia.INTRODUCTIONIndonesia produces over 200 Mt of clean coal and is the second largest coal exporter to Japan, accounting for about 32 Mt of coal annually. Over 99% of the coal produced in Indonesia comes from surface mines. More open cut mines will be developed and more coal will be mined in order to fill the great demand both in Indonesia and the rest of the world.In open cut mines in Indonesia, there are many sites where mining operations have developed long highwalls that have been abandoned due to the current economics. Mining operations have been transferred to lower stripping ratio blocks of coal or overlying seams. In some cases, coal lies buried beneath spoil heaps or is covered with mud and water. It is estimated that there is a great deal of coal beneath abandoned and working highwalls. Considering these situations, it seems to be worth introducing highwall mining systems into Indonesian open cut mines.Final highwalls of open cut mines can form the starting point for other mining methods, such as highwall or underground mining. In its basic application, highwall mining is a technique utilized after an open cut portion of a reserve has been mined, sometimes prior to the introduction of underground mining (Seib, 1993). In this system, the coal seam is mined by remotely operated equipment, such as an auger machine or a modified continuous miner incorporated into a highwall mining system. The major problems with highwall mining systems are less coal recovery due to leaving coal as the pillars and the instability of openings and highwalls due to the pillar and roof failures."

Jan 1, 2010

By E. R. Pantos

US coal production increased 3% to a record 832 Mt (917 million st) in 1987, according to preliminary Energy Information Administration (EIA) data. Most of the increase was due to the unusually warm summer and the increased coal-fired electricity demand for air conditioning. Drought conditions in the Northwest lowered hydroelectric generation, contributing to the higher use of coal by electric utilities. However, excess production capacity and increased competition from natural gas added further downward pressure on delivered coal prices, continuing the declining price trend of the last several years. Coal production by region Appalachian coal production reached 402 Mt (443 million st) in 1987. This is about 3% more than in 1986 and just short of its 1984 peak. Virginia produced 7% more than its 1986 level, due to increased coal-based electricity demand. Smaller percentage increases were attained in eastern Kentucky, Pennsylvania, and West Virginia. Ohio and Alabama were the only major coal-producing states in Appalachia that produced less coal in 1987 than in the previous year. In the Interior region, 1987 coal production reached a record 182 Mt (201 million st), about 2% above 1986. Illinois is the largest coal-producing state in that region. Production there fell about 3.7%, primarily because of lowered demand at electric utility plants in Alabama and Tennessee. However, this was more than offset by production increases in western Kentucky, Texas, and Indiana. After falling slightly in 1986, coal production in the West resumed its upward trend to a record 248 Mt (273 million st). Wyoming is that region's dominant coal producer. It mined 7% more coal than in 1986. Wyoming's increase offset the 11% decline in New Mexico production and smaller declines in other Western states. Coal consumption and prices Domestic coal consumption reached a record 759 Mt (837 million st) in 1987. Most of the increase resulted from the unusually warm summer that led to higher than normal peak demands for electricity in the third quarter. Electric utility coal consumption was also boosted by the below-normal hydroelectric generation that resulted from low water levels in the Northwest. These factors more than offset the effects of increased nuclear power generation and competition from natural gas. As a result, coal provided 56.9% of electric utility generation in 1987, compared with 55.7% in 1986. Electric utilities consumed a record 651 Mt (718 million st) of coal. While electric utility coal consumption increased, the average cost of coal to utilities was down, from $1.58 per million Btu in 1986 to $1.52 in 1987. The average price of coal delivered to utilities in 1987 was $35.09/t ($31.84 per st), the lowest since 1981. Coal prices were held down by a glut of coal supplies and by a decline in the average price of natural gas to electric utilities. Coal consumption at coke plants in 1987 was 2.6% above the 1986's 32.5 Mt (36 million st). This increase reflects steel's recent resurgence. Coking coal demand, though, was reduced by the increased use of continuous casting and electric furnace technologies. The average price of coal delivered to coke plants fell from $56.02 to $51.35/t ($50.83 to $46.59 per st). Coal consumption in the industries other than coke plants amounted to 68.2 Mt (75.2 million st) in 1987, slightly less than in 1986. Coal lost part of its market share to natural gas, which was priced favorably relative to coal. The average price of coal delivered to manufacturing plants was at its lowest level of the current decade. It fell from $39.50/t in 1986 to $37.27/t ($35.84 to $33.81 per st). Residential and commercial coal consumption fell to 6.2 Mt (6.9 million st) that is 9.8% below 1986 and the lowest since 1980. This decline is also attributed to the relatively low price of natural gas in 1987. Coal stocks Coal consumers held 169 Mt (186 million st) of coal stocks at the end of 1987, 5.9% above the 1986 year-end level. Most of this increase was due to stockpiling by electric utilities in anticipation of a possible strike by the United Mine Workers of America early in 1988. Stocks at electric utilities increased to an estimated 154 Mt (171 million st) at the end of 1987, 5.6% higher than the previous year. This was much lower than 1984's stock buildup. Coke plants increased their coal stocks by 30% in 1987 to 3.5 Mt (3.9 million st), rebounding from the unusually low inventories of 1985 and 1986. Other industries increased their stocks slightly in 1987. Coal producers and distributors ended 1987 with 25 Mt (28 million

Jan 5, 1988

By Pierre Gouvin

This paper describes the design, installation and monitoring of a state of the art real time geotechnical/structural instrumentation monitoring system to facilitate tunnel construction under Interstate route I-5 in Seattle, Washington, USA. The project involved removal of existing highway foundation substructures on both North and Southbound lanes as well as the underground reversible high occupancy vehicle lanes. The system utilized state of the art 3-D pulsed laser scanning, wireless sensor networks, automated robotic total stations, tilt beam sensors, narrow angle tiltmeters, and in-place inclinometers. Dedicated real time data loggers, with a web based graphical interface, provided 24/7 access to critical measurements. In addition to the instrumented sections of wall and roadway subsurface which monitored physical measurements at known points, the pulsed laser scanning allowed complete site monitoring coverage where physical sensors were not located. This data allowed post processing at any location enabling the contractor and designer to respond to unforeseen structural responses to construction. Use of the instrumentation system resulted in the early detection of wall movement, and provided feedback to the designers to facilitate construction process changes in order to minimize further movement.

Jan 1, 2010

By Alan G. Mayton

The Bureau of Mines conducted a study to (1) determine from laboratory tests the feasibility of a photographic method for determining reflec-tances that may be applied to measuring in-mine mineral reflectances and (2) formulate a procedure for collecting and analyzing the data. The method uses a 35-mm camera with automatic flash and a gray-scale re-flectance standard to collect on film the reflectivity data in under-ground mineral mines. After the film is processed, the data on the photographic prints are analyzed in the laboratory with a photometer. Test results show the photographic method can provide values of reflec-tance to within ±5 pet of full scale (full scale = 100 pet). The method's usefulness for determining reflectivity values, within similar limits of absolute percent error at the lower end of the scale, however, has not been completely resolved by the study and consequently warrants further investigation. The method offers an acceptable means for collecting and analyzing reflectivity data for reflectivities at the higher end of the scale, i.e., 50 pet or above; it should be used with caution when reflectivity values are below 50 pet. Four films were evaluated; all gave relatively satisfactory results.

Jan 1, 1987

By D. J. Jr. McAdam

PART I. OUTLINE OF INVESTIGATION, DESCRIPTION OF MATERIAL AND METHODS RESULTS of investigation of corrosion-fatigue of metals at the U. S. Naval Engineering Experiment Station, Annapolis, Md., have been discussed by the writer in several recent papers.1,2,3,4 In those papers references were also given to the work of Haigh in 1917.6 Efforts by the writer to obtain a better understanding of some of the factors involved in corrosion-fatigue finally developed into a general investigation of the effect of time and cyclic stress on corrosion of metals. Corrosion fatigue of Metals As described in the papers mentioned, rotating-cantilever specimens, conically tapered so that the stress is nearly uniform over a length of about 1.5 in., were subjected to simultaneous fatigue and corrosion. For this purpose a stream of water was diagonally applied so as to sweep the specimen from the outer to the inner fillet and surround the stressed surface with water. The fresh water is a calcium carbonate water, the composition of which has been given in a previous paper.2 The salt water is Severn River water having a saline content about one-third that of sea water.

Jan 1, 1928

By Ian M. F. Arnold

"Occupational health programs and their role in improving the quality of working life in the mining industry are discussed. Attention is directed to some problems peculiar to the Canadian mining industry. Factors affecting program development are reviewed, as well as parameters affecting cost-benefit analyses.IntroductionThe quality of working life in the mining industry is a more important consideration than in many other industrial environments because of the very nature of the undertaking. It was a strange paradox of the 1960s that preventive maintenance programs for machinery and equipment were well accepted, whereas the concept of ""preventive people medicine"" was basically ignored. Fortunately, there seems to be a swing toward the development of occupational health programs in many sectors of the business community; however, there is a noticeable lack of consistency and uniformity for thought among the members of the mining industry. The blame for this lack o f progress in the occupational field cannot be entirely attributed to the industry, but must also rest with (for the most part) apathetic and inadequately trained physicians. This latter problem is slowly improving with the growing recognition that a well-planned and executed occupational health program may improve the quality of working life for mining employees and their families.There are a number of factors which relate to occupational health in mining, and its effect on working life quality. Included among these are:1. Community isolation.2. High accident risks.3. Occupational disease risks.4. Production demands and the state of the economy.5. Government regulatory requirements.6. Travel demands.These, and others, reflect on all levels of the mining industry. To examine how these factors can be moderated by an occupational health program, it is necessary to first review the rationale for such a program and some of the costs related to it."

Jan 1, 1983

By P. Kolettas

The development of novel methods for the investigation of the subsoil contributes to the improvement of geotechnical research, enhances the obtained geotechnical characterization and may reduce the investigation cost by reducing the number of required tests. Non-destructive testing methods, performed either in situ (i.e. electrical tomography, seismic refraction, etc) or in the laboratory can provide initial data and perhaps estimates of rock/soil properties. This study focuses on the development of rock material properties and/or characteristics based on non-destructive laboratory testing of a number of stones, ranging from porous (bioclastic) limestones to impervious marbles. Seismic velocity measurements as well as attenuation signals were digitally recorded using a digital oscilloscope. Data were processed using a novel technique of spectral analysis available through special Matlab packages employing Fourier transform methods. More specifically, the NFFT (Non Equispaced Fourier Transform) transformation was applied to seismic waves traveling through the subsoil using the Autosignal program (by Seasolve) and the Specgramdemo program included in the Signal Analysis toolbox of Matlab 6.5 (Mathworks). Results indicate a definite relationship between the frequency content of the signal and the rock type as well as the degree of saturation of the specimen.

Jan 1, 2008

By Jon C. Volkwein

The U.S. Bureau of Mines has developed a method to measure methane and other gases during the auger mining of coal. An intrinsically safe commercial gas detector with a built-in data logger was mounted in the center of the hollow conveying auger. A sampling head through the wall of the auger conducted a gas sample to the detector. Results showed that gas levels can be monitored on a continuous basis during the auger mining of coal and the data retrieved upon completion of the hole.

Jan 1, 1994

By J. McCreedy

"The addition of Portland cement to hydraulic sand fill has resulted in the production of stable and self-supporting cemented sand fill. The use of cemented fill in the mines of The International Nickel Company has resulted in substantial economies in timber requirements, de-creased dilution of ore and greater flexibility in mining methods.Coupled with special mining techniques, it has permit-ted mining by both cut-and-fill and shrinkage stoping methods to much greater depths than heretofore. The use of cemented sand fill has permitted revisions to undercut-and-fill mining which have significantly improved the efficiency of this method.Automated mixing systems have been developed for preparing cemented sand fill in surface sand plants on a continuous throughput basis. Control of cement-sand mixtures is obtained by the use of a mass flow measuring system and weighing cement feeders."

Jan 1, 1966

By Perry Olcott .

THE Taka oil field is in the northern part of Titus and Franklin Counties, in north- eastern Texas. The small town of Talco, from which the field derives its name, is on the P. & Mt. P. R. R., about 15 mi. north of Mt. Pleasant, the county seat of Titus County. The oil field extends east and west from the town of Talco, the approximate center. In May, 1924, R. L. Cannon, while doing surface geology for the Humble. Oil & Refining Co., mapped the surface trace of this fault structure as evidenced by Upper Midway faulted down against Lower Midway. In the interval of sixteen years between the original surface work and the recent productive well completion, approximately eight wells were drilled into the Woodbine sand without success. The structure was well defined by those tests and all of the wells en-

Jan 1, 1936

By John B. Hastings

Ten miles from Hartsel, near Antelope springs, in Park county, Colorado, there is a large area of unconsolidated lake-beds, which are interesting because at least a part of the lacustrine sands contains in the aggregate an immense amount of gold. During 1906, one of the arms of this dessicated lake was fairly well prospected with shafts and cuts by an Eastern company to test its value, as favorable amounts of gold had in some instances been found upon it. The claims of the company contain about 5,000 acres of the beds; bat this is only a small portion of them, a south branch from a main body, which is at least 7 miles in diameter, with other and very wide lateral gulches, paralleling the one herein described on the east and west. A certain amount of digging and sampling was done in the outside areas; but the result was evidently unsatisfactory, since the work was discontinued. This section of Colorado has not been studied geologically, and the age of the ancient lake is unknown. It is probably Quaternary. I spent two weeks on the ground, in September

Jan 1, 1909

I. THE ENERGY CRISIS STILL EXISTS A. ALTHOUGH IMMEDIATE SHORTAGE IS NOW ALLEVIATED BY: 1. Increased imports through lifting of Arabian embargo; a. Imports were 6.5 million bpd during the week ended January 17, or 1.3 million bpd higher than last year. b. 1.7 million bpd higher than March '74. 2. Decreased demand resulting from higher prices and conservation. a. January 1975 demand was 17.9 million bpd, 0.1 million bpd lower than January 1973 and … b. 2.0 million bpd, or 10% under originally projected demands for January 1975. c. Gasoline (excluding tax) went up 59% from 27d/gal in August 1973 to 43c/gal in September 1974. d. Gasoline demand for January 1975 was 6.3 million bpd, 0.1 million bpd higher than 1973 but 0.7 million bpd ( 10% ) under projected demand. 3. Increased crude and major product inventories. a. January 17, 1975 crude and major product inventory was 794 million bbl, 99 million bbl higher than the same date in 1973. b. 105 million bbl increase since April 12, compared to only 38 million bbl increase during the same period in 1973.

Jan 5, 1975

By J. T. Carlson

Dolomite [CaMg(CO3)2] is an intolerable impurity in phosphate ores, due to its MgO content. The need to develop a cost-effective method for the removal of dolomite from high-MgO phosphate ores becomes increasingly important as high-grade reserves become depleted. The jigging process has been investigated as a method for the beneficiation of phosphate ores. A laboratory-scale jig was constructed and tested using a semicontinuous, ?through-the-screen? jigging process. Two types of sedimentary phosphate ore were used; a sample from Plant 1 in the 4.00 x 0.85-mm size range, containing 1.55% MgO, and a sample from Plant 2 in the 3.40 x 0.85-mm size range, containing 3.07% MgO. These were tested, using previously optimized jigging parameters, at high and low feed rates. For the Plant 1 phosphate ore, a phosphate concentrate that contained 0.89% MgO was achieved with a bone phosphate of lime (BPL) recovery of 32.0%. For the Plant 2 phosphate ore, a phosphate concentrate that contained 1.38% MgO was achieved, with a BPL recovery of 74.7%. Minimum achievable MgO grades were also determined by analyzing hand-separated phosphate samples.

Feb 1, 2012

By Robert W. Hunt

Delays in the completion of the alterations to the plant at the works of Messrs. Oliver Bros. and Phillips, in Pittsburgh, coupled with the increased demand for metal made from regular Bessemer pig, placing the firm many hundreds of tons behind in their deliveries, prevented Mr. Henry W. Oliver, Jr., from redeeming his promise to place his works at my disposal for further tests of high-phosphorus irons, until May 5th. Upon that date, I assumed charge of the operations in his steel-plant. Mr. Oliver had purchased Neshannock pig as a basis for a supply of phosphorus. My information is to the effect that this iron is made from low-grade Lake Superior ores and mill-cinder, the latter "ore" being utilized to about 40 per cent. of the total mixture. At all events the pig had quite as much phosphorus, and in as varying quantities, as the most exacting could desire. My experiments of last fall had well satisfied me as to the effect of from 0.35 to 0.55 per cent. of phosphorus in the Clapp Griffiths metal. Hence at this time my first trials were directed to

Jan 1, 1886

By I. A. Menshikh, S. A. Kotov, N. L. Shinkarkin

All the cycle for conversion of natural and reprocessed uranium of ROSATOM’s “TVEL” Fuel Company is concentrated at the Siberian Chemical Plant. Conversion capacities are located on two sites, i.e. the Radiochemical Plant, which refines feedstock, and the Conversion Plant, which produces uranium oxides and uranium hexafluoride. Liquid radioactive waste arising in the process, after pretreatment, is transferred to a dedicated national operator for underground disposal. Environmental strategies pursued by the Fuel Company involve the introduction of process solutions intended to eliminate liquid radioactive waste and convert it into a solid phase. In the 5–7 years coming, work will be performed to refurbish and upgrade conversion facilities of the Siberian Chemical Plant that will principally change its radioactive waste management scheme. This paper describes the current waste management scheme and sets out planned schemes for management of natural and reprocessed uranium waste, which will be implemented in the refurbishment of conversion facilities of the Siberian Chemical Plant. The new technologies for the management of liquid radioactive waste from uranium conversion described in the present paper have an undeniable advantage over the current technology mainly due to significantly less environmental harm.

Jan 1, 2020

Iran possesses very large copper resources, estimated to contain around 4-5% of the world's known copper inventory. There are several small private sector copper mining operating in the country, but Iran's copper industry is dominated by the state-owned National Iranian Copper Industries Company, which operates the world-class Sar-Cheshmeh open-pit Mine. This mine was developed in 1970s before the 1979 Islamic Revelation by the Atlantic Richfield Company (ARCO), the former Anaconda Copper Mining Company. Current Iran?s copper cathode production is about 250,000 mtpa and recently it is targeted to reach to 700.000 t by 2014. The required finance for this target is estimated US $2.25 -b, i.e. US $5000 for each tonne capacity. The copper content of the mineable reserves of the country is estimated about 19 Mt. It is not unlikely this amount increases in close future. Currently, almost 30 projects consist of mine, concentrator, smelter, refinery, acid plant, leaching, bio-leaching are underway. These projects are a golden opportunity for the local and foreign companies, but the recent sanctions are very challenging that all studied in this paper.

Jan 1, 2012

By J. C. Tremolada

El proceso de recuperación de los metales preciosos, minerales, concentrados y relaves refractarios, implica un desafío en la hidrometalurgia en la actualidad. En este sentido, el presente texto señala la biolixiviación como tratamiento preliminar para la extracción de oro en concentrados refractarios piritosos. Para tal fin, se estudiaron los parámetros críticos que influyen en la velocidad de oxidación de un concentrado refractario de oro encapsulado en pirita, concluyendo que la adaptación del Thiobacillus Ferrooxidans Atcc 19859 en la superficie de la pirita a PH 1.8, influyó en la cinética de oxidación de la pirita. Asimismo, su aplicación se expande al tratamiento de la arsenopirita y pirrotita cuando poseen oro encapsulado.

Apr 1, 1991

By E. F. Jr. Young, H. E. Steinman, G. C. Smith

Through a progressive laboratory and pilot-plant program Jones & Laughlin Steel Corp has analyzed and corrected mine drainage pollution problems at all of its coal mines. In conducting this program, the company found no "typical" drainage discharge. Each discharge point at each mine was unique, so that varied approaches were needed to eliminate stream pollution. To illustrate the variety of these approaches, the treatment of drainage from foul, discharge points at three mines in Pennsylvania will be considered here. The flows and critical analyses of the drainage sources and treated effluents arc shown in Table I. Hydrated Lime Works at Thompson Borehole The discharge stream from the Thompson bore- hole at the Vesta No. 5 mine flowed into a small branch creek where it created a "yellowboy" deposit and affected aquatic life. Investigation indicated that hydrated lime would neutralize the acid and precipitate ferric iron without aeration. Treatment of the 150.000-gpd flow, however, created about 4000 gpd of wet sludge for which there was no nearby accumulation site. With State approval, this sludge was deposited through an unused borehole into an abandoned section of the Vesta No. 6 mine several miles away.

Jan 1, 1970