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By John L. Halls

INTRODUCTION In this section, it is assumed that the reader is an engineer with sufficient training in underground mining work, preferably with budgetary control, to understand the mining methods outlined in other sections of this handbook. The mining-method descriptions are not repeated herein; only sufficient information is provided to enable the reader to comprehend the development of the costs presented. All costs are in 1977 US dollars, except where explicitly stated otherwise. CAPITAL INVESTMENT The capital investment in the underground mining portion of any mining property includes the following: 1) The development of original access involving adits, shafts, declines, etc. It includes the necessary equipment for transporting men, materials, and rock. 2) The purchase of mine equipment including loaders, underground haulage equipment, fans, pumps, electrical distribution, surface facilities associated with the underground mine, etc. 3) Sufficient preproduction mine development to assure steadily increasing production after startup. De- pending upon the mining method used, the preproduction development should provide a supply of three months to one year of ore that is developed and is ready to be stoped. Underground development also includes excavations other than shaft stations, loading pockets, sumps, etc., which usually are associated with the means of access and are excavated by the contractor. These excavations could include a crusher cavern, an ore- storage pocket, and underground workshops that may or may not be included by the shaft-sinking contractor. Portions of these could be delayed until after production begins, but it is preferable to complete them during the development phase, so there is no interference with the production buildup. 4) The staff and labor costs for all phases from inception through final production. 5) The provision of mine-surface equipment and facilities strictly applicable to the underground portion of the operation. The required facilities include a changehouse with a lamp room, a first-aid station, compressors, an electrical substation, workshops, a ware- house, water pipelines to the concentrator, water storage tanks, explosive storage, etc. A concrete-batch plant, a sand-fill plant, and boilers for heating may be required. 6) Other direct and indirect costs. 7) Engineering, design, and procurement costs. 8) Contingency allocations. 9) Contractor's fees, startup costs, and owner's costs. Original Access As part of a study for the US Bureau of Mines, Dravo Corp. conducted an extensive literature research survey covering underground operations in the United States between 1963 and 1973. Table 1 is compiled from the section of that study pertaining to the types of access to underground mines. Table 1 does not include distances attributable to the deepening of existing shafts, nor does it include shafts bored by raise drills or downhole machines that need existing underground workings for the disposal of the cuttings. During the period under review in the report ( 1963 through 1973). concrete-lined circular vertical shafts were the predominant means of providing the first access to a new underground mine; these shafts accounted for 80% of the original access in terms of the number of accesses completed, and 75% in terms of the total verti- cal linear distances. The inside diameters of the conventional circular shafts ranged from 3.7 to 7.0 m (12 to 23 ft). Most (72% ) of these conventional shafts were for production,

Jan 1, 1982

By F. D. Everett

This report summarizes the results of a nationwide investigation completed in 1964 to determine the nonferrous base metal ore reserves and potential sources of ore and to evaluate criteria for their ultimate exploitation. Engineers of the Bureau of Mines contacted mining company officials, reviewed reports and Government records, and where necessary made personal appraisals in arriving at the results. The estimates are presented by metals in ores in geographic regions and include some of the problems affecting the reserves and potential sources. The recoverable metal in the measured ore category and in the total ore reserves was estimated as follows: [ ] At the 1963 rate of domestic mine production these total reserves would be adequate to provide copper for 62 years, lead for 121 years, and zinc for 42 years. Data also are given for gold, silver, and other coproducts. Reserve estimates greatly exceed those of previous investigations; some prior estimates of copper reserves are included for comparison (table 23). Projections of requirements for base metals indicated the United States will need approximately 45 percent more copper in 1970 and 110 percent more by 1980 than was consumed in 1960; similar projections for lead indicate increases of 20 percent by 1970 and 45 percent by 1980; zinc projections are 40 percent more by 1970 and 90 percent by 1980. Much of the production of gold and silver is a coproduct of base metals recovery and the projected need for the precious metals exceeds all the United States can produce. Some problems of the industry are mentioned. A graphic evaluation of the economic availability of the reserve and potential sources is shown.

Jan 1, 1967

By Eric R. Bauer

The ground control aspects of extended depth-of-cut mining are presented in this U.S. Bureau of Mines report. A trend analysis of extended cut approvals was performed. A comparative review of roof fall fatalities for extended and nonextended cut mining is included. Current ground control guidelines for extended cut approval are summarized. The problems and concerns of this extraction system are addressed, and typical extended cutting face operations are described.

Jan 1, 1993

Shane is enjoying his new work. Six months ago, he was stocking shelves at his local supermarket and decided to make the big move to a job in mining with more challenge and, of course, more dollars. He's been through his inductions, received his training tickets and is now working in a crew of eight underground at a fly-in, fly-out (FIFO) operation. There are many more systems and processes here than in his retail job, and Shane's comfortable that his safety is being looked after. He is enjoying the continually changing work and conditions, it makes the job interesting. It's taking some time to get used to the roster and he is worn out by changeover, but he gets more time with friends and family during R & R.   Generally, the mining industry has a maturing safety culture and well developed systems. This sometimes lulls people into a false sense of security. Safety systems cannot anticipate every possible situation, nor can they replace people's perception, thinking and decision-making. To manage safety, it's critical to find the right balance between dependence on systems and a healthy fear and respect of risks we face.   As safety standards are raised, systems tend to get more thorough and complex. When a new person joins a mining crew, we induct and train them to provide the information they need. As labour availability again becomes short, and many new people join our industry, we shouldn't assume they know the fundamentals. We need to explain not only what they are expected to do, but why doing what we ask and expect will keep them safe. We must equip people to deal with both the routine and the unexpected.   This presentation explores the challenges of balancing a structured, systematic approach to safety with the need to also equip people to deal effectively with risks everyday in dynamic and extraordinary situations.   Session purpose Introduce participants to a way of looking at risk from a different perspective, as a force for change and progress, if managed well. Demonstrate that risk is something we need to engage with emotionally as well as physically, if we want our risk management efforts to be successful. This purpose will be achieved through an entertaining and engaging presentation, using photos and case studies. The session will initiate interest to explore new ways of thinking about risk and generate discussion about the balance between people and systems. What is the right balance and why getting it right enhances the safety culture, while getting it wrong can impact on safety, business performance and sustainability.

Jun 1, 2010

By J Lane, D J. Barker, B Pei

Queensland Alumina Limited (QAL) is the worldÆs largest producer of smelter grade alumina, located in Gladstone, Queensland, Australia. The plant employs evaporative cooling towers for waste heat rejection. Process water requirements include red mud residue disposal, steam venting to the atmosphere and Calcination feed moisture. Raw (untreated) water consumption in 2001 was 37 700 m3/d or 3.8 m3 per tonne of production. The Gladstone region experienced a water shortage in the period 2001 to 2003, resulting in progressive water restrictions. Industry operated under a ten per cent restriction from April 2002 and in November 2002 a 25 per cent restriction came in force. The maximum restriction level of 50 per cent was anticipated for the middle of 2003. Water restrictions of these magnitudes have the potential to result in significant production limitations, which would have major economic consequences for QALÆs owners, customers, suppliers and employees. Therefore it was imperative that measures be found to mitigate the impact of these restrictions. Furthermore, as one of the largest water users in the Gladstone region, QAL had an obligation to the community to minimise water usage as much as possible. A thorough analysis of water usage on site was conducted, focussing on all water streams leaving the plant. The philosophy used was that by minimising water outputs, the inputs would follow suit. Where possible, preference was given to solutions that provided lasting water savings. This occurs when the value of the water saving justifies the project cost, irrespective of water restrictions. By June 2002 an average water saving of 19 per cent was achieved, almost double the required saving. By end November 2002 further projects had increased the total water saving to 29 per cent, mainly through the re-use of GladstoneÆs municipal treated effluent as wash water. Further measures to reach the target of 50 per cent reduction were investigated. The evaporative cooling system was to be replaced with seawater cooling, using cooling towers to minimise the seawater pumping cost. Another benefit of this concept was the ability to dispose of the cooling tower bleed stream with the existing system for neutralised red mud disposal. This would avoid the need for an additional environmental outfall from the plant. In February 2003 the Gladstone region received over 500 mm of rain, which boosted water reserves to five years supply at forecast usage rates. This led to the lifting of all water restriction. As most of the implemented water savings measures are economically viable in the absence of water restrictions, raw water usage at QAL is still less than 75 per cent of pre-2002 levels.

Jan 1, 2003

By AIME AIME

REGISTRATION and licensing of engineers is now being given consideration by a special committee of the Institute, authorized at the March meeting of the Board of Directors. The subject is one that has recently been or is now actively before engineering organizations in many of the States of the Union. In Washington, D. C., the Washington Society of Engineers and the local sections of ten national engineering societies, including the A.I.M.E., recently had a joint committee investigate the subject: this committee formulating a proposed law that has been presented to Washington engineers for their consideration. At the same time, the committee has summarized the reasons for and against registration of engineers in Washington, D. C. As many of these reasons are of more than local application, they are here reprinted so that all members of the A.I.M.E. may be informed on the subject. It is expected that some report of the Institute's Committee on Registration, State Councils and Professional Development will he made at some forthcoming meeting of the Board of Directors.

Jan 1, 1932

By J. Visman

FOR more than 25 years evaluations of coal cleaning units have appeared in many publications, and during this time considerable progress has been made in developing the theory and techniques of calculating washery results. A variety of characteristics have been defined over the years, many receiving general recognition during the first post-war Coal Preparation Conference in Paris in 1950. Coal preparation has become a science, and the approach to preparation problems is being revolutionized. Formerly, for example, if a coal operator wanted to know the performance of a given cleaning unit for a particular grade of his run-of-mine, he either shipped a carload to the manufacturer for a test run or relied on a report of a test carried out on a coal similar to the one he intended to clean. In modern practice the expensive, time-consuming test work generally can be avoided if the washability curves of the coal in question and the error curve of the cleaner are known. Normally a guarantee can be given on the strength of this information. General acceptance of modern standards has thus reduced the need for pilot-scale models of existing types of coal cleaners. Needless to say, the method requires exhaustive and accurate information on the cleaning unit and on all the additional circumstances affecting its results, in- formation that ultimately can be secured only from actual tests made in the laboratory or in the washery.

Jan 10, 1954

By C. T. Yavuz

Higher environmental standards have made the removal of arsenic from water an important problem for environmental engineering. Iron oxide is a particularly interesting sorbent to consider for this application. Its magnetic properties allow relatively routine dispersal and recovery of the adsorbent into and from groundwater or industrial processing facilities; in addition, iron oxide has strong and specific interactions with both As(III) and As(V). Finally, this material can be produced with nanoscale dimensions which enhance both its capacity and removal. The objective of this study was to evaluate the potential arsenic adsorption by nanoscale iron oxides, specifically magnetite (Fe3O4) nanoparticles. We focused on the effect of magnetite particle size on the adsorption and desorption behavior of As(III) and As(V). The results show that the nanoparticle size has a dramatic effect on the adsorption and desorption of arsenic. As particle size is decreased from 300 nm to 12 nm the adsorption capacities for both As(III) and As(V) increase nearly 1000 times. Interestingly, this increase is more than expected from simple considerations of surface area and suggest that nanoscale iron oxide materials sorb arsenic through different means than bulk systems. The desorption process however, exhibits some hysteresis with the effect becoming more pronounced with small nanoparticles. This hysteresis most likely results from a higher arsenic affinity for magnetite nanoparticles. This work suggests that magnetite nanocrystals and magnetic separations offer a promising method for arsenic removal.

Jan 1, 2006

By Larkings RH

The high gas emissions associated with the depth of mining and very high coal extraction at some Australian Collieries have provided a need to investigate the influence of geological and mining conditions on levels of gassiness. The introduction of longwall extraction in particular is associated with complex strata control problems and quick changes in gassiness. To this stage of Australian coal mining, no standard method has been developed to predict the different levels of gassiness associated with the various geological and mining conditions; and the relationship between coal output and total methane make has not been established. For local conditions, with a large number of coal seams lying in close proximity to the working seam, the significant contribution of gas emissions from adjacent strata was expected, especially as strata relaxation occurred during longwall mining. This depends mainly on geological conditions, strata control and coal production. For the deepest of the B.H.P. Collieries in the Newcastle region, the relationship between coal output and total methane make has been investigated by systematic gas balance measurement during longwall extraction. The computer method of iteration was used to approximate the mathematical equation from the initial graphs of coal production versus quantity of methane in the ventilation system for various strata conditions. The angle of caving was established for local geological and mining conditions, for planning and design of the positions of cross measure boreholes.

Jan 1, 1986

By Mathews K. E, Willstead T. V C

Initial glory holing was followed by sublevel stoping, with a small proportion of total production mined by shrink and cut-and-fill methods.The sublevel stoping method was successfully modified to cater for altering ground conditions encountered at increasing depths. At present, 94 per cent of production comes from sublevel stopes. The evolution of this mining method and current techniques and practices is outlined. A combined shrink and,sublevel benching method was also developed to increase the mining rate of narrow orebodies over the standard stoping lift of 380 ft. Pillar recovery and stope filling operations have been continuously modified to suit the relIuirements of a rapidly developing mine.INTRODUCTIONOre production commenced at Mount Isa Mines in June 1931. Since then production has increased from approximately 2,500 tons of lead ores per mine day to the current 11,000 tons of sulphide ores per mine day comprising 3,100 tons of lead ore and 7,900 tons of copper ore. The early planners selected sublevel stoping with ring drilling for ore breaking as the most efficient and economical for Mount Isa conditions: This method satisfied requirements for:1. a low cost mining method for the comparatively low grade ores,2. a stoping sequence allowing development, stope preparation, breaking and drawing of ore to proceed concurrently,3. a method of extraction in which broken ore in the stopes would be kept to a minimum because of adverse effects of oxidation on mill metallurgy and...

Jan 1, 1961

By Waldemar Lindgren, Clyde P. Ross

To the miner, as well as to the geologist, the eastern part of Cuba is a most interesting region. Here we find, in contrast to the moderate relief predominating elsewhere in the island, an imposing mountain range, the Sierra Maestra, extending east and west parallel to the coast, its precipitous front facing the blue Caribbean Sea. In a geological sense this range is largely an unknown land, the only well-explored region being that in the vicinity of Santiago. The range also contains the most important mineral deposits of the island. They comprise, first, a series of iron deposits yielding a partly hematitized magnetite with low content of phosphorus; second, a remarkable copper-bearing vein at El Cobre; and third, various manganese deposits. Probably more deposits will be found, for the larger and western part of the range is as yet little explored and its slopes are covered by a thick tropical jungle. The following notes are based on a short visit by the senior author in January and February of 1914 to the mines at Daiquiri, El Cobre, and Mayari. For many courtesies and great assistance he is deeply obliged to Charles F. Rand, President of the Spanish-American Iron CO.; to George W. Pfeiffer, General Manager, and to the several members of his staff. Geological Features of the Sierra Maestra For our knowledge of the geology of the Sierra Maestra we are indebted to reconnaissance work by Fernandez de Castro, R. T. Hill, Mr. C. Hayes, T. W. Vaughan, and A. C. Spencer. The summary by the latter three geologists furnishes the best guide to the region.' The range is undoubtedly outlined by a great east-west dislocation. Its southern slope drops abruptly to the sea, while on the north side a much gentler declivity leads down to the rolling plateau of Tertiary limestone which occupies much of the adjacent part of the island. Viewed

Jan 1, 1916

By Marvin J. Udy

THE preparation of this paper is in response to many requests for in-formation on the mining and smelting developments which have been carried on for the past three years or more by the Chromium Mining and Smelting Corporation of Canada. By way of introduction, the following paragraphs, relating to the early history and present status of the chrome-mining industry in the United States, are of interest. They are quoted from Bulletin No. 76 of the California State Mining Bureau, published in August, 1918: 'Chromium was discovered about 1797 by a French chemist, Louis Nicolaus Vauquelin, in ore from Siberia. From that time until 1827, the Urals, in the region of Ekaterinburg, supplied the chromium used in . Europe. In the summer of 1827, as the historian advises us, Isaac Tyson, Jr., saw in a Baltimore market-place a cart containing a cider barrel, which was held from rolling about by some heavy black stones. He had made a study of such stones at the first-known American locality, the Bare hills near his father's home, six miles from Baltimore, and he recognized the black stones as chromite. On inquiry, he found the chromite came from the Reed farm in Harford county, 27 miles northeast of Baltimore. At this time, Tyson was one of the very few men in the country who knew the value of chromite, and in the next few years he took full advantage of this knowledge. He immediately bought the Reed farm. He found about 30 tons of float-ore on the surface, but there was no outcrop of ore in place. Never-theless, he sank a shaft, and at a depth of eight feet struck an ore-pocket which proved to be 80 ft. long, 25 ft. wide, and 8 ft. in maximum thickness. His next discovery was of placer chromite in the sands in the beds of brooks on an estate called Soldiers' Delight, 16 miles northwest of Baltimore. Thus far, Tyson's observations had shown him that chromite occurred apparently only in serpentine areas. His explorations were now leading him farther afield. In 1828, he found on the Wood Farm, in Lancaster county, Pennsylvania, a deposit of float chromite which led him to lease the ore-right of the farm, which he finally purChased in 1832. Here he developed the famous Wood mine, the largest single producer of chromite in the world.

Jan 1, 1938

By Osvaldo A. Bascur, J. P. Kennedy

Companies have installed powerful desktops for their personnel and instrumentation and control systems in their plants. These desktops are, in many cases, connected to a company intranet. Still, process engineers have to obtain their data manually. Engineers use process calculations from manually calculated averages from the plant; field operators collect equipment data on log sheets; and maintenance engineers collect critical information on log sheets. All of this information resides in individual machines. What are the strategic tools that will enable collaboration between them? How can operators, engineers, and managers access plant information to proactively increase their effectiveness in process troubleshooting, plant debottleneclung, aligning with business strategic and customer demand, satisfying environmental and safety regulations, developing capital projects, and implementing control strategies? A nonintrusive environment at the desktop is required to provide the process information to these workers. How can value be added to MS Windows technologies with the legacy systems at a minimum cost? There is no straight answer; however, there is a proven framework to leverage the large investments in new technologies. Objects and components are changing the way everyone relates to their computer and networks. Three examples will be described to demonstrate paradigm change. Today, process engineers can access data at the required level of detail for analysis of critical process variables at their desk or remotely. 1. Process Troubleshooting and Analysis: The engineer can develop an inferential calculation, trigger a process advisor to deter- mine the behavior of the units for the last day, and get the population of a set of batches (heats, blocks, rolls, sheets, etc). 2. Process Control and Optimization: The engineer can connect to a process simulator at steady state or a dynamic simulator of the process to evaluate new control strategies or process unit line-ups and use the process simulator as a process observer for fault diagnosis. 3. Collaboration with Accounting and Maintenance: The engineer can review reconciled data and the process mass balances, suggest maintenance cleaning or recalibration of flowmeters, and evaluate key control performance of all advanced controls.

Jan 1, 1999

By D. S. Hutton, W. C. Leslie

Thermal etch patterns developed on poly crystalline 3.5 pct Si-Fe by heating in hydrogen or in argon have been examined. The most prominent feature of the etching is the development of striations on grains with (100) planes near the plane of the surface. These striations are probably produced by the resoution of a random, high-energy plane into (100) facets of lower energy. THE thermal etching of iron and iron-base alloys has a long history. The phenomenon was observed by Osmondl more than 70 years ago. The literature on thermal etching between that time and 1951 was reviewed by Olney,2 and a briefer review appeared in 1958. 3 The only articles which have been found dealing with the thermal etching of silicon iron are those of Dunn and Lionetti4 and of Dunn, Daniels, and Bolton,5 and they reported only grain boundary etching. EXPERIMENTAL PROCEDURES A cast 3.5 pet Si-Fe alloy was given a metallo-graphic polish and etch, then placed in flowing purified hydrogen for 6 hr at 2200°F. The same specimen was later repolished and etched to remove the thermal etching. The specimen was then held in flowing purified argon at 2200°F for 72 hr. In both instances the specimen was rapidly cooled by being pulled up quickly into the cold zone of the furnace. All photomicrographs shown are of the surface as removed from the furnace. Oblique illumination was essential for observation of the thermal-etching effects with a light microscope and was used for all the photomicrographs. RESULTS AND DISCUSSION Grain boundary etching, grain boundary movement, and contouring within grains are illustrated in Fig. 1. The contours within a single grain followed behind the advancing grain boundary. To determine the average contour interval, or step height, white light was used in an interference microscope. The steps were of the correct magnitude to separate while light into its spectrum of colors. A green light was focused at the top of a contoured area, shifting to red across the field. By using the difference in the dominant wave length of red and green light,6 and counting the number of steps across the area, it was possible to obtain a value of about 80A for the average step height. Laue back-reflection patterns of four grains with contour lines showed that the grains had a (100) plane slightly inclined to the plane of the surface (± 5 deg). Insofar as this could be determined from their irregular traces, the contour lines within a grain had a common direction, <100> ± 5 deg.

Jan 1, 1961

Albert Sauveur, Cambridge, Mass. (written discussion).— In his introductory paragraph, the author states that he has come to bury Beilby, not to praise him. The paper, however, gives the impression that while he may have dug the grave, Beilby is still at large. I am not one of those whom the author calls enthusiastic supporters of Beilby&apos;s amorphous theory and in support of this claim quote from a book I am writing: "Attractive as the amorphous theory is, and notwithstanding the ability with which it has been presented and the renown of its sponsors and supporters, it should not be accepted without reservations as a demonstrated fact.... So long as it explains more satisfactorily than other theories a greater number of phenomena in which it may play a part, we should use it in preference to others as the best available. Let us avoid the danger, however, into which too many fall, of accepting as indisputable truths, statements and theories emanating from those whom we hold in great esteem. It is not what those men themselves would wish us to do. I am entitled, I think, to occupy a position in the middle ground. Neither should Howe be classified with the enthusiastic supporters for he has written that the theory should be classed rather among the precious working theories than among those firmly established," a very wise and prudent statement. Jeffries, on the other hand, I would not hesitate to describe as an enthusiastic supporter. The author reproaches the advocates of the amorphous theory with having taken whatever properties they needed and with having assigned them arbitrarily to the hypothetical amorphous phase. He then applics their method to small crystals. If the existence of an amorphous phase is assumed, its greater tenacity and greater hardness is satisfactorily explained in the words of Howc: &apos;(This greater strength is natural, because the amorphous state lacks the cleavages and slip planes which weaken crystalline substances." Can the greater strength and hardness claimed for small crystals be as satisfactorily explained? Nor do I think that the cold deformation of metals through successive slips within the crystalline grains can he accounted for as acceptably by the "small crystals theory."

Jan 1, 1923

Albert Sauveur, Cambridge, Mass. (written discussion).— In his introductory paragraph, the author states that he has come to bury Beilby, not to praise him. The paper, however, gives the impression that while he may have dug the grave, Beilby is still at large. I am not one of those whom the author calls enthusiastic supporters of Beilby&apos;s amorphous theory and in support of this claim quote from a book I am writing: "Attractive as the amorphous theory is, and notwithstanding the ability with which it has been presented and the renown of its sponsors and supporters, it should not be accepted without reservations as a demonstrated fact.... So long as it explains more satisfactorily than other theories a greater number of phenomena in which it may play a part, we should use it in preference to others as the best available. Let us avoid the danger, however, into which too many fall, of accepting as indisputable truths, statements and theories emanating from those whom we hold in great esteem. It is not what those men themselves would wish us to do. I am entitled, I think, to occupy a position in the middle ground. Neither should Howe be classified with the enthusiastic supporters for he has written that the theory should be classed rather among the precious working theories than among those firmly established," a very wise and prudent statement. Jeffries, on the other hand, I would not hesitate to describe as an enthusiastic supporter. The author reproaches the advocates of the amorphous theory with having taken whatever properties they needed and with having assigned them arbitrarily to the hypothetical amorphous phase. He then applics their method to small crystals. If the existence of an amorphous phase is assumed, its greater tenacity and greater hardness is satisfactorily explained in the words of Howc: &apos;(This greater strength is natural, because the amorphous state lacks the cleavages and slip planes which weaken crystalline substances." Can the greater strength and hardness claimed for small crystals be as satisfactorily explained? Nor do I think that the cold deformation of metals through successive slips within the crystalline grains can he accounted for as acceptably by the "small crystals theory."

Jan 1, 1923

By Vladimir Grujic, Milorad Grujic, Ivan Djurkovic, William Riggs

"In this paper, we have studied efficiency of different chemical structures of frothers on copper ore Majdanpek. The goal was to find out the best suitable chemical structure, which allows good bubble formation, size and interaction, forces on mineral surface. The particle size distribution was between 10 and 100 µm. Our research was oriented on three groups of frothers: alcohols, poly glycol ethers and poly glycols.We also used different collectors based on similar or less similar alcohol group in chemical structure as in frothers, expecting higher stability of air bubble in contact with copper minerals. Minimal potential energy was determinate in the hydrodynamic conditions for different particle sizes. It was founded that it is proportional to air bubble volume on 0.88° and contra proportional to the kinematics viscosity of pulp.Analyzing the results, we find out that poly glycols decreased surface tension the most. Also, it increased amount of coarser particles to the top of pulp. This group is less sensitive to pH value compared to the others too.From the class of frothers with higher efficiency in flotation process, we pointed OrePrep X-75 and X-133 as frothers with expressive frothing characteristic in the alkaline and low alkaline circuits. Special suitability of those frothers for floating copper minerals makes their hetero polar molecules with more than one hydrocarbon radicals connected to one polar group. However, those froters have no nether high or low solubility and are non-ionization. Those froters indicate some small collecting characteristics too. In dispersion systems, those two frothers make two types of bubbles: smaller di < 1.2 mm; V = 0.0008 cm3 and middle di < 16 mm; V = 2.2 cm3 (di – Bubble diameter, V – Bubble volume). Transportation speed of air bubbles it is possible to calculate based on equation: ?s = 27.5 * di 1.4 cm/s. Distribution of free surfaces for chalcopyrite is average 80% in the class –74µm +10µm and 20% in the class -10µm. If we get all class sizes, we find that recovery (R) depends from the time by equation:"

Jan 1, 2003

By M. J. Bennett

"The Quemont mill is primarily a differential flotation plant in which copper, zinc ·and pyrite concentrates are recovered. Native gold and silver are associated in the form of very small particles with all the minerals contained in the ore: chalcopyrite, sphalerite, pyrite, pyrrhotite and even with the gangue rock.The proportion of the precious metals associated with chalcopyrite is such that the best recoveries we can obtain in our copper flotation concentrate are about 68 percent of the gold and 51 percent of the silver in the ore. In order to improve the total recoveries of precious metals it is necessary for us to float a pyrite concentrate and treat it by cyanidation for the extraction of whatever gold and silver we can obtain in this manner. In spite of the fact that we regrind this concentrate to 75 percent minus 325 mesh, it is difficult to extract much more than half of the gold and silver present in the pyrite concentrate by cyanidation, due to the extremely fine association of the precious metals with the pyrite.In 1963 we produced 86, 853 ounces of gold by flotation alone, and 14, 581 ounces by cyanidation. These amounts are equivalent to 67. 74 percent and 11. 37 percent respectively of the total gold in the mill heads. Comparable figures for silver are 325, 598 ounces by flotation and 99, 448 ounces by cyanidation; and 51.37 percent and 15.69 percent respectively.The total annual value of these metals (ie. $4, 000, 000) qualifies Quemont as a precious metal producer of some note. On the other hand, it is evident that by far the greater proportion of our gold and silver production is contained in copper flotation concentrates. When the income from our copper and zinc values is also considered, the much greater importance of flotation compared with cyanidation in our operation may be appreciated. This explains why most of our work on controls has been carried out in our flotation mill, rather than in our cyanide plant. Some of the controls installed there could, of course, be employed in either type of operation."

Jan 1, 1964

By Robert D. Pehlke, Robert G. Blossey

The solubility of nitrogen in liquid iron alloys containing chromium and nickel has been measured in the temperature range 1550° to 1700°C at nitrogen pressures to 1 ah. The solubility surface has been determined for the iron corner of the liquid metallic ternary to 21 pct Cr and 11 pct Ni. The nitrogen solubility increases markedly with increasing chromium concentration. The effect of nickel and the bilinear effect of chromium and nickel are less pronounced. The solubility data are presented, and interaction coefficients are determined from them. THE solubility of nitrogen has been determined in liquid Fe-Cr-Ni binary and ternary alloys. The work in this laboratory has been directed toward a relatively limited composition range, that is to 20 pct Cr and 10 pct Ni. Humbert and Elliott1 studied the entire ternary; but their investigation was, understandably, limited in this region. The region considered here is of the greatest commercial interest. Knowledge of the solubility in these alloys is important for accurate control of the nitrogen levels in various stainless alloys. Also, the solution behavior is of theoretical interest because of its deviations from ideal dilute solution rules at moderate chromium levels. The nitrogen solubility in the iron binaries has been reviewed extensively by Pehlke and Elliott,2 particularly with respect to the dilute solution interaction parameters. More recently, there has been some interest in accurate descriptions of solute interactions in non-dilute solutions. Most of the investigators have adopted a power series fit to accommodate any non-linearity of the data. The Taylor series expansion is adopted here, using Scimar&apos;s notation3 for the interaction coefficients. An alternate method, instead of requiring higher-order expansions, is to restrict the range of the composition variables. A planar solubility surface may be fitted to the data and its range of validity determined. If the axes of this region are displaced from the usual origin—the solvent pure iron—a change in standard state is required for the solution reaction. The standard state for nitrogen in iron is commonly taken as the hypothetical 1 wt pct solution of nitrogen in pure iron. However, for an alloy of appreciable solute concentration, e.g., 13 pct Cr or 18 pct Cr-8 pct Ni, it would be convenient to use that base composition as the solvent and redefine the solution reaction in terms of that particular solvent. A brief derivation follows, defining the free energy of solution in an alloy solvent. Following the treatment by Darken and Gurry,4 for a nitrogen pressure of 1 atm: N (pure component) = N (1 wt pct in solvent) [l] AG=RT ln100/ wt pct N in solvent Taking this reaction for an alloy solvent less the same reaction for a pure iron solvent the relation between nitrogen in pure iron and an alloy is: N (1 wt pct in Fe) = N (1 wt pct in alloy) [2] AG = RT[ln(wt pct N in Fe) - ln(wt pct N in alloy)] Adding ½ N2(g) to each side and subtracting N (1 wt pct in Fe) = ½N2(g), the total free energy for solution of nitrogen in an alloy, referred to nitrogen at infinite dilution, is given by: ½N2 (g) = N (wt pct in alloy) L3] AG°3 = -RT ln(wt pct N in alloy )PN =1 atm Interaction parameters have their usual meaning when ?G°/RT is differentiated with respect to the proper composition coordinate. If desired, the dilute alloy treatment may be utilized with the new reference composition as the solvent. This has. indeed, been done by Small and pehlke5 in their analysis of nitrogen solution in liquid 18-8 alloys. The Sieverts&apos; technique was used for this investigation on an apparatus previously described.6 The materials used in this program were: Ferrovac-E iron, 99.95 pct, Crucible Steel Co.: chromium, 99.95 pct, Union Carbide Metals Co.; nickel, 99.9 pct, International Nickel Co. Recrystallized alumina crucibles were used with no evidence of crucible-melt reaction. RESULTS The locations of the ternary compositions investigated are shown in Fig. 1. The data of Turnock7 and small8 have been alluded to in other papers.5&apos;6 There were no departures from Sieverts&apos; law observed for

Jan 1, 1969

By J. M. Dean, R. L. Grayson

Introduction With the continued downward pressure on coal selling prices, mine management must make its operations as efficient as possible. The problem is the same one throughout the mineral industries, streamlining operations to maintain competitive min¬ing costs (Born, 1991). There has been a great deal of research into better using production manpower. But the story is different for operations support personnel. Traditionally, planning man¬power requirements are done annually, with modifications to the operating plan occurring generally quarterly. On the other hand, the demands on manpower are often dynamic, being responsive to changing productivity levels, mine conditions (including water influx, bad roof, poor floor) and unanticipated project requirements (responses to machine breakdowns or a new section setup requirement because of a drop in coal quality in another area). Such changes may impact the manpower structure significantly. At times they may cause serious labor relations problems concurrently. Realignments and the generation of instability in the workforce because of active job switching (bidding) are a result. Most responses by coal operators are reactive rather than proactive, a situation that could be mollified by more accu¬rate and detailed planning of predictable manpower require¬ments. A manpower planning tool is needed that takes into consideration such things as changing productivity levels and conditions as manhour requirements for different work areas are planned, rather than blindly allocated through traditional staffing modes. Mine Management Support System The Mine Management Support System (MMSS) is an integrated decision support system that was developed using Sun Microsystems hardware according to the contract be¬tween the US Bureau of Mines and West Virginia University. The software used in the development of MMSS included X¬ windows (Scheitler and Gettys, 1986) for the user interfaces, LASER (Raman, 1985; Hayhurst, 1990) for the expert sys¬tem and graphics components, and the C language for general programming requirements. Sun DOS was used to allow the use of IBM-compatible applications software on the Sun networks. Sun OS is the operating system. It can be viewed as an enhanced version of UNIX. One of the components of MMSS that was developed to address the many specific objectives outlined in Grayson et al. (1990) is the work scheduling system. MMSS accom¬plishes work scheduling by using a mathematical (goal) programming approach to minimize the amount of switching of workers from their regular jobs to perform other jobs (Grayson and Nutter, 1991). Manpower support program The main objective of MANSUPP is to plan a detailed manpower structure for a mine by incorporating a production schedule, condition-modified work standards and manage¬ment preferences to predict required manhours for various support activities, for example, belt moves. This is accom¬plished by gathering and processing planning information the same way a mine planner would. The program is menu¬driven with the selection of a particular menu item locating the user in the appropriate area within the spreadsheet to review/add information. All of the interactions between productivity, section conditions and management prefer¬ences and their effect on the amount of support work required must be considered. Information regarding the productivity of a particular section, the geometry of the section, work standards for individual activities and section conditions must all be gath¬ered for input into the program. In the initial stages of development, it was decided that the program be developed in an environment that mine planners were familiar with in order to accommodate the use of the program. Lotus 1-2-3 or a compatible (Quattro Pro) met this environmental need. Other reasons included ease of calculation due to built-in functions, powerful command language and macro capabili¬ties. Each of the major components of the program defined are summarized. Production schedule This area allows the user to input a production schedule for the entire mine over 12 periods. Space has been provided for five sections, advance or retreat, and two longwall sections. There are several calculations occurring in this area that do not apply to the determination of manpower, but serve as an aid in production planning. Section description The section description area of the spreadsheet is shown in Table 1. The first three items are calculated in the production schedule area of the worksheet and then transferred to this location. The remaining information is input by the user to be used in later calculations.

Jan 1, 1996