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By E. H. Jr. Dix

DURING an investigation of high-strength manganese bronze by the Engineering Division of the Air Service, at McCook Field, Dayton, Ohio, particles of a "blue constituent" were noted in the microstructure of most of the bronzes examined. The constitution of the simple copper-zinc base alloy is still a matter of dispute in spite of the fact that the copper-zinc series is one of the oldest industrially important groups of alloys, and has received the early consideration of scientific research. The diagram, according to the most recent work,1 is shown in Fig. 1. The disputed questions involve the termination of the beta field and the line at 470° C. The earliest experimenter, Roberts-Austin, detected an arrest in some of his cooling curves at approximately this temperature and ascribed them to the formation of a eutectic; it has since been proved that there are no eutectics in this series. Shepherd2 was unable to detect any thermal arrests at this temperature; his diagram was essentially as shown in Fig. 1, except that the line at 470° C. was omitted and the beta phase carried down to normal temperatures. Later, Carpenter and Edwards,3 by a very painstaking research, definitely established the authenticity of the line but attributed it to the breakdown of the beta constituent into a eutectoid of alpha and gamma. Microscopic evidence of the formation of the eutectoid is doubtful and it seems more likely to be due to an allotropic change in the beta constituent as shown by Fig. 1. At least for practical purposes, it is more convenient to think of the structure of a 60-40 brass as a mixture of alpha and beta prime crystals rather than alpha plus an unresolvable eutectoid of "apparent beta" as it has often been called.

Jan 5, 1922

By A. McKenzie

During the late 1990s Anglo American PLC was evaluating the Gamsberg zinc deposit in the Northern Cape Province. As the primary South African metallurgical technology provider, Mintek became involved in the evaluation of a pyrometallurgical process for the recovery of zinc from the Gamsberg deposit. eloping DC arc furnace technology for the metallurgical industry. This includes the patented Enviroplas® process for the treatment of zinc bearing waste materials. As a consequence Mintek has developed extensive expertise in the pyrometallurgical processing of zinc bearing materials. However, Mintek?s technologies stopped with the production of Prime Western Grade (PWG) zinc. Early on in the evaluation of the Gamsberg project, it became evident that the refining of PWG zinc would play an important part in the economic viability of the project. At the time the only pyrometallurgical technology available for the refining of PWG zinc to Special High Grade (SHG) zinc was the New Jersey process. This process represents 50-year-old technology and has not undergone significant refinement since the technology was developed. In order to provide a complete pyrometallurgical flow sheet for possible implementation at Gamsberg, Mintek assessed the New Jersey process with a view to either improving the technology or developing a new technology appropriate to the 21 century. In 1998 Mintek convened a consortium consisting of Mintek, the University of Cape Town, Eskom Enterprises, Bateman Metals and Anglo American PLC. The consortium successfully applied to the Innovation Fund for funding to develop a new process for the pyrometallurgical refining of PWG zinc to SHG zinc. The main aims of the project were to develop a new technology for pyrometallurgical zinc refining that conformed to the following: ?Decrease the production cost of SHG zinc metal to stimulate the development of the Gamsberg deposit. ?Be compatible with the current Enviroplas® process, preferably as an add-on to that process. ?Should use electrical energy to benefit from local price tariffs. The project commenced at the beginning of 2000 and consisted of three phases: ?an initial technology search and assessment of the fundamental aspects of zinc distillation. ?the design of a pilot plant for zinc refining. ?the manufacture, commissioning and operation of the pilot plant. A new technology based on a DC arc boiler feeding a packed distillation column was developed and during 2003 the project culminated in the successful operation of a 200 kg/h pilot plant. Ultimately, all of the aims of the project were met and the main outcome is that an advanced process for the pyrometallurgical refining of zinc (the Zincref process) has been developed. The main innovation of the technology was the switch from an energy transfer limited process to a mass transfer limited process (for which a patent has been registered).

Jan 1, 2004

By J. M. W. Mackenzie

The interactions between oil drops and mineral surfaces have been examined for the cetyltrimethylammonium bromide (CTAB)-quartz and sodium dodecyl sulfate (SDS)-hematite systems. The results have been interpreted using a electrical double layer interaction model, a "sweeping-penetration" model based on steric interactions and a free energy of adhesion model. The adsorption of long-chain ions at the mineral interface was also studied and found to follow a Fuerstenau-Modi model of combined Coulombic and chain-chain interaction forces. The basis of the emulsion flotation process and the feature which makes it differ from conventional flotation is: encounter, followed by adhesion, between oil drops and mineral particles which are suspended in an aqueous environment. The manner in which the adhesion between these two phases contributes to the flotation process may be through the formation of min-eral-oil drop-mineral linkages, mineral-oil drop-air bubble linkages, or a combination of both. Possible flotation mechanisms derived from these adhesion processes are shown schematically in Fig. 2 while Fig. 1 shows an example of the first mechanism for quartz particles which have been floated using a cetyltrimethyl-ammonium bromide (CTAB)-Nujol emulsion as collector. In Fig. 2 the three phases, mineral, oil, and air, for convenience have been shown as having approximately equal size. This would not always be the case in an actual emulsion flotation operation. For the flotation of sand-sized particles of approximately 0.5 mm diam, the mineral particles would be at least ten times the size of the largest emulsion drops present in the system, while in the flotation of —10u slime particles, the mineral phase may be of the same order of size as the oil phase. The air bubbles in a flotation cell are normally about 1 to 2 mm in diam and therefore, in general, would be larger than the oil drops. Although the relative size of the three phases does not alter the basic adhesion processes between oil drops, mineral particles, and air bubbles, which depend on the physical and chemical properties of the interfaces involved rather than on the extent of these interfaces, it does alter the degree of deformation of the oil drops and air bubbles which will occur on adhesion. For mechanisms 1 and 2 to take place, the oil-water and mineral-water interfaces must be partially replaced by a mineral-oil interface while in mechanism 2 there is the additional requirement that the oil-water and air-water interfaces must be replaced by an oil-air interface. In view of the importance of the oil drop-mineral particle encounter and subsequent adhesion stages to both of the emulsion flotation mechanisms discussed, a study has been made of some physicochemical factors which control these processes for Nujol-cetytri-methylammonium bromide (CTAB)-quartz and Nujol-sodium dodecyl sulfate (SDS) -hematite systems. Experimental Electrokinetic Measurements.—The zeta potential of mineral particles was measured using a streaming potential technique similar to that described by Fuerste-nau.1 The streaming potential was measured using a multirange electrometer while the plug conductivity was measured using a 50 cycle sec1 bridge. Measurements were made on 28 x 65 mesh particles. Contact Angle Measurements.—A captive bubble technique was used to measure the contact angles for air bubbles and oil drops. The angles were measured on fracture faces of unmounted minerals which proved easier to clean than polished mounted specimens and should more closely represent a flotation system. Reagents: These have been described in a previous publication.0 Minerals: Rock crystal quartz from the New England district, N.S.W., was used for contact angle and streaming potential measurements. The quartz was hand

Jan 1, 1971

By T. J. Durbin

At some surface and underground mines, control of ground-water inflow involves significant costs. These costs include the capital costs for installing a dewatering system, power and other costs to operate and maintain the system, and costs to treat and dispose of the water that is collected. To minimize these costs, design of a dewatering system utilizing wells has been formulated in terms of a nonlinear operations research problem using quadratic programming. Using this formulation, the locations, depths, pumping rates, and pumping schedules of wells are selected so as to minimize the total costs of the dewatering system.

Jan 1, 1993

By Norman Lecuyer, Jacque Nantel

"The Chadbourne Project, located within the limits of the town of Noranda, Quebec, will make use of backfill materials to fill the voids left by the mining of stopes and pillars. A series of tests were conducted on different mixtures of slag and pyrrhotite tailings materials to evaluate their properties. The tests are described and some pertinent results are given in the paper.IntroductionThe Chadbourne Project is located in the centre of the Town of Noranda, Quebec, with houses as close as 120 m from the blasting operations. The ore is mined using the vertical crater retreat method. The voids left by mining activities will be filled. A program of pillar recovery will follow.Considering the proximity of houses and the need to recover pillars, the backfill program must be carefully laid out. No subsidence can be tolerated on surface.With these objectives in mind, a test program was undertaken by Nantar Engineering Limited and Queen's University to evaluate the possible ba ckfilling alternatives available to Chadbourne. One of the possibilities retained was the use of a backfill composed of broken slag material from the Horne Smelter and pyrrhotite tailings deposited on the Horne's pond a number of years previously.The back fill used at the Horne Mine until the mine closed in 1975 was composed of a mixture of 97% granulated slag and 3% pyrrhotite tailings. The tests leading to its use underground at the Horne Mine were described by Patton in 1952. The structural properties of the Horne backfill were ""intuitively"" known; it was agreed by all at the Horne Mine that the backfill was behaving remarkably well. Some were labeling it ""the best backfilling material in the world"". Its strength was said to be that of a weak concrete. All of the preceding indicate that the Horne backfill had never had its structural and other properties determined in the laboratory."

Jan 1, 1983

By D J. Black

The process of excavating and mining coal causes fractures in the overlying and underlying strata. The fractures provide pathways for gas released from coal seams and other gas-bearing strata to flow into the mine workings. Coal seam gas typically contains high concentrations of methane with lesser concentrations of carbon dioxide. Low concentrations of other gases such as nitrogen, hydrogen sulfide and ethane may also be present in some coal seams. In certain geological settings, particularly in close proximity to geological structures, such as faults and dykes, the concentration of gases contained in a coal seam can vary significantly between methane-rich to carbon dioxide-rich.In mine design and planning it is vital that mining engineers gather sufficient information to accurately determine the content and composition of the gas present in the coal seam and develop an understanding of changes in these parameters within the planned mining area.The longwall method of mining coal causes fracturing of the overlying and underlying strata behind the retreating longwall face. Where coal seams and other gas-bearing strata are present within the caving zone, gas will be released from the strata leading to contamination of the mine workings. If the rate of gas emission exceeds the diluting capacity of the mine ventilation, the concentration of gas in the mine may exceed the statutory limit, resulting in production delays and potentially unsafe conditions.CITATION:Black, D J, 2016. Planning effective management of gas emissions in an underground coalmine, in Proceedings Life-of-Mine 2016 Conference, pp 44–47 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jun 28, 2016

By C. E. Brown, D. C. Helms, O. W. Shimer

The early history and progress of anthracite stripping, from the first known operation at Summit Hill in 1821 through 1917, was covered in 1917 in a paper by J. B. Warriner,1 then chief engineer, now president of the Lehigh Navigation Coal Co., and stripping methods between 1917 and 1931 were the subject of a paper in 1931 by H. H. Otto,2 of the Hudson Coal Company. . The present paper is confined to methods used today on pitching beds in the western middle and southern anthracite fields. The anthracite industry, not unlike other large industries, had been affected for more than a decade by the adverse economic conditions of the country. High development and operating costs and the competition of other fuels caused some collieries to be closed temporarily, while others were permanently abandoned. In order to obtain a larger tonnage at a lower development cost, a larger stripping program was put into effect by many companies. In 1932, stripping operations accounted for 3½ million tons, or 7 per cent of the total anthracite production of the year, and in the next 10 years this increased until more than double that amount, or over 14 per cent of the total production, was from stripping operations. These figures represent the total production of the entire anthracite region; unfortunately, the figures have not been separated from the different fields. There are some operations in the southern and middle western fields where the tonnage obtained from stripping amounts to more than 30 per cent of the total colliery production. Stripping operations on pitching beds present difficult problems. Owing to the various geological formations, a different situation is encountered in nearly every stripping pit; and because of the proximity of an overlying bed, it is very often necessary to load the entire overburden into trucks and haul it out of the pit to the dump area, although back filling and casting is done whenever possible. Beds in the areas described in this paper pitch from 20" to 90 and some are on the invert in many sharp folds and faults. Planning The more successful strippings have had adequate engineering analysis. Some work is being done without much preliminary planning, but many strippings would have failed completely if close supervision by the engineering department had not been . maintained. Locations of stripping areas are determined as follows: I. By constructing cross sections over the areas and drilling sufficient diamond-drill or well drill holes to study the strata and to determine the location, thickness

Jan 1, 1944

By Park Wright

The fact that granite has been encountered by the drill by those in search of oil and gas in Kansas is becoming more and more a matter of interest, not only to the oil producer but to everyone directly and indirectly connected with the oil business. It is, therefore, time that someone should offer an explanation for its presence and form a definite opinion, based on all the data available, in regard to the effect it will have on the future prospects of the area affected as probable oil-and gas-producing territory. At present there seems to be no consensus of opinion. To the writer's knowledge, only one attempt has been made to explain ; by Erasmus Haworth, State Geologist of Kansas, in a paper entitled Bulletin Number Two on Crystalline Rocks in Kansas. The purpose of the present paper is to offer a theory for the presence of the granite, and to draw conclusions which will aid in determining the prospective oil and gas value of the area in question. In taking up this question it will be well to consider first the tests in which granite has been reported, with a general history of each. The accompanying map (Fig. 1) shows the location of all wells described. The first well in which granite was reported was that drilled just south of Zeandale in section 27, township 10 south, range 9 east, by a local company which had taken up a block of leases in that vicinity. At a depth of 958 ft. (291.99 m.) granite was encountered. Drilling was continued to a depth of 1093 ft. (333 m.) in the same formation, at which depth the hole was abandoned. Another well was started 1 mile east of the first well and the same rock was found at a depth of 945 ft. (288 m.). Drilling was continued to a depth of 1200 ft. (365.76 m.) with the bit in the same formation. Samples of the drill cuttings have been examined and they are undoubtedly crushed granite. The next well in which granite was found was that drilled by DeLaat and Shepard, independent wildcat operators, in section 34, township 19 south, range 7 east, near the town of Elmdale. Granite was struck at 1707 ft. (520 m.) and the hole was abandoned in the same formation at 2525 ft. (769 m.). Mr. DeLaat watched the drilling of this well very closely and he has described to me in some detail the formation immedi-

Jan 1, 1918

By Wm. Bleloch

SYNOPSIS The feasibility of rejection of nitrogen from stack gas by recycling of top-gas with cold-blast 95 to 98 per cent oxygen is assessed. It is concluded that nitrogen could be removed to a level below 3 per cent of the stack-gas using recycled cleaned cold top-gas and 95 to 98 per cent oxygen produced by a single-column air separation plant with liquid-air reflux instead of liquid nigroten reflux. The partial pressure of carbon monoxide in the stack-gas could be doubled without top pressure and the deposition of carbon and reduction of iron oxides by the stack gas could be markedly increased. It is concluded that rate of stock descent could be doubled compared with present-day practice and an iron make of 4400 kg/m 2 of hearth area/hour may be attainable with a working volume of 129 m2/m hearth diameter by this method. Oxygen consumption is estimated at possibly 280 m2 (0.4 t)/t iron made and carbon consumption at possibly 280 kg/t iron. Power consumption for oxygen including auxiliaries is estimated at 304 kWH/t 100 per cent oxygen as 95 to 98 per cent gas. The air separation cycle due to Schuftan is discussed in some detail, and the components of a 1 600 metric ton/day separation plant are briefly discussed. The paper is a theoretical essay.

By J. E. Tress

The Bureau of Mines has developed a process to utilize waste heat from electric arc steelmaking furnace gases to preheat the ferrous material charged to the furnace. Four heat exchangers were designed, tested, and operated successfully on 1-ton electric arc furnaces. Briquets and pellets were charged continuously, both countercurrent to the hot furnace offgasses and at ambient temperatures. A comparison of the electrical energy consumed in each situation showed that preheating can lower energy requirements as much as 15.6 percent.

Jan 1, 1975

By Pan Gu, Zhen Zhang, Jiang Diao, Bing Xie, Hongyi Li

Viscosities of FeO-SiO2-V2O3-CaO-P2O5 slags have been measured at the temperature range of 1673 K to 1773 K (1400°C to 1500°C). This investigated system represents the major components of basic vanadium slag that is an important intermediate product of a novel vanadium extracting process, in which removal of phosphorus and extraction of vanadium can be achieved from the vanadium-containing hot metal simultaneously. It was found that higher CaO/SiO2 ratio resulted in lower viscosity in the composition range of interest. Also, the viscosities increase with the increasing P2O5 concentration. The varying viscosities can be attributed to the modification in complexity and polymerization of the slag network. The variation of apparent activation energies are in tune with the viscosity measurements. The results of this work revealed the effect of CaO/SiO2 and P2O5 on the viscous properties of FeO-SiO2- V2O3-CaO-P2O5 slags and therefore provide the theoretical foundation for the control of the coupling de-P and V-extraction process.

Jan 1, 2016

By James E. Harding

AT just about the geographical center of the peninsula of Lower California is the El Arco gold mine. It is small and spotty, and three separate attempts to operate it in the past have failed. The only reason the present operation is possible is because of the higher price of gold and because the previous operators had spent about $300,000 developing the property with shafts, four levels, machinery, and a complete mill, all of which was acquired at a bargain price. All the known ore in the mine, to say nothing of the cost of recovering it, is

Jan 1, 1937

By T. H. Davis

Twelve laboratories from the Western United States and Canada participated in radon progeny intercomparison measurements at the U.S. Bureau of Mines radon calibration facility in March 1987. The participants intercom pared grab-sampling and automated equipment methods at high and low concentrations of radon progeny and condensation nuclei (CN). The objective of this intercomparison was to determine if the measurement procedures and equipment of the North American facilities are equivalent. The sampling results showed good agreement among all participants. The standard deviation for the working level measurements was less than 3.5% for 1.70 working level (WL) and less than 8.8% for 0.21 WL. This relatively good agreement was achieved by using alpha standards calibrated by National Bureau of Standards (NBS) and by closely checking and monitoring airflows.

Jan 1, 1989

By Jean-François Dorion

La corrosivité des environnements miniers souterrains est un phénomène peu étudié au Canada. En plus de détériorer les systèmes de soutènement, la corrosion s?attaque aussi à divers installations et équipements souterrains. Cette étude, débutée en janvier 2007, est l?établissement d?une banque de données afin de caractériser les environnements miniers souterrains selon leur potentiel de corrosivité pour les systèmes de support de terrains. Pour ce faire, cinq (5) mines ont été sélectionnées afin de comparer les environnements : Laronde, Géant-Dormant, Niobec, Mouska et Doyon. À chacune des mines, trois (3) endroits ont été étudiés. Les résultats préliminaires démontrent une grande variabilité des conditions d?une mine à l?autre ainsi qu?à l?intérieur même d?une mine. La minéralogie des roches et du gisement influence la composition des eaux souterraines et la présence des sulfures joue un rôle important sur l?agressivité de l?eau et de l?air des mines de l?étude. Afin de déterminer le potentiel de corrosivité, plusieurs paramètres doivent être considérés et la mine doit être zonée selon l?agressivité des endroits.

Feb 1, 2008

By Cristian Rodriquez, Fernando Fernandez, Rodrigo Fuentealba, Tom BoBo, Maria Rocha, John Kemeny

This paper describes a case study that was conducted at a new mine in South America. This mine has significant geologic variations that will result in different distributions of hard and soft ore being mined at different periods of time over the mine life. A study was conducted to determine the optimum blast design that will meet the mill throughput requirement of 95,000 tonnes (104,720 tons) per day for the first 10 years of the mine life. As part of this study, field rock mass characterization and laboratory tests were conducted. This includes standard rock mechanics tests as well as rock breakage tests used in mill simulations. The geology of the ore body was broken up into four Geologic Units, and statistical variations in the properties were determined for each unit. Using this data along with the data on the occurrence of the different geologic units over time, simulations were made of the run-of-mine (ROM) fragmentation due to different blast designs, and these results were used in simulating the resulting throughput after crushing and grinding. Four blast designs were considered with powder factors of 0.44, 0.54, 0.64 and 0.94 kg/t. The results of this study show that determining the proper blast design is important in ensuring that the mill throughput requirement will be met over the mine life.

Jan 1, 2015

In November 1992, the Internal Revenue Commission (IRC) was formed from the rperggr of the Papua New Guinea Taxation Of- fice (PNGTO) and the Bureau of Customs, and now has the re- sponsibility for the administration of direct and indirect taxes on a national basis in Papua New Guinea (PNG). Since that date we have undertaken many initiatives to make the new organisation more efficient and responsive to clients' needs. Income Tax The mining industry is catered for, in respect of income tax, un- der a separate taxation regime within the Income Tax Act (ITA), Division 10, as well as some general provisions within that Act as may be applicable. Division 10 is itself broken up into subdi- visions to cover the different types of mining leases, namely Spe- cial Mining Leases (SMLs) and Mining Leases (MLs), and peri- ods of time during which those sub-divisions apply. Ring Fencing Income tax assessed on the mining industry, with the exception of Mining Leases (these will be explained later), has a project basis of assessment, that is, each project is assessed separately as if the taxable income of the taxpayer from operations attributable to the project was the only assessable income derived by that taxpayer. This is often referred to as "ring fencing". This is an important point to consider because losses from unsuccessful projects cannot be set off against income from those that are suc- cessful, except in very limited specific circumstances, such as where an unsuccessful exploration licence is cancelled or surren- dered. The project basis of assessment applies to both resident and non-resident companies. A relaxation in the 'ring fence' provisions was applied from 1st January 1995, where ten percent of exploration expenditure, in- curred in areas outside of Special Mining Leases and Petroleum Development Licences in a particular year of income, can be claimed as an outright deduction which is limited to ten percent of the tax otherwise payable in that year. This was introduced to encourage exploration in PNG.

Jan 1, 1997

By E. R. Maize

This report is the third of a series on convergence of roof and floor in coal mines and subsidence of surface that accompanies it. The first paper5/ dealt with extraction in a mechanized mine (Montour 10) having relatively short rib lines that retreat rapidly. The second dealt with extraction in a mine (Crucible) in which coal was loaded. by hand and in which the rib lines wore long and slow-moving. The present report deals with a mine (Gibson) in which conditions approximated those in the Crucible mine, except that the distance between room centers was considerably less and the pillars were narrower in consequence. Moreover, the average cover was less and the studies were made under the steep hillside of a stream valley compared with a gently rolling surface over the portions of the second mine studied. Gibson mine lies in the east-central hart of Washington County, Pa. , approximately midway between the Montour 10 end Crucible mines on a north-south line. A cooperative agreement covering the work was made with the Hillman Coal & Coke Co. through W. L. Affelder, vice president. This paper describes the methods used in the investigation, gives excerpts from the data obtained, and offers such generalizations as appear to be justified.

Jan 1, 1940

By B. V. Driga

The paper presents the evaluation method of the thermal power potential of the salt lakes developed in collapsed salt mines in Romania. It is well-known that the hydro-chemical stratification of these lakes favors warmer internal layers. The degree of heat varies during the year, but, taking into account the large number of genetic lakes of this type, it can be used as a local utilizable power source. The authors analyze the correlations between the physico-chemical parameters of the water and the degree of heat stored as a function of the morphological parameters of the lakes, as well as the technical parameters for capitalizing on this power.

Jan 1, 2008

By David Schroeder, John Chipman

Jan 1, 1964

The Fifty-ninth Regular Meeting of the Rocky Mountain Coal Mining Institute convening at the Hotel Colorado in Glenwood Springs, Colorado, was declared in session at 10:30 a.m., by Past President Charles M. "Dock" Schloss, Schloss and Shubart, Inc., Denver, Colorado. Dock introduced Mike Zakotnik, Jr., General Superintendent, The Kemmerer Coal Company, Frontier, Wyoming, President of the Institute. His introduction of President Zakotnik follows: Fellow Members, including our charming and beloved secretary, Gussie Whiteside, and our lovely Mrs. Cerise: It is now the appointed time to convene the Fifty-ninth Regular Meeting of the Rocky Mountain Coal Mining Institute which I now declare in session. At our last meeting we elected Mike Zakotnik, Jr., President, and lie has served the Institute intelligently and industriously since his election.

Jan 1, 1963