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By E. J. Eisenach, Edward Matsen

AT the present time the Climax Molybdenum Co. is the largest molybdenum producer in the world and the operator of the largest underground mine in North America. It has grown steadily and rapidly since its beginning in 1917. Only 250,000 lb of MoS2 were produced during the first year from 1917 to 1918 when the company was formed. Operations were suspended shortly thereafter because of the lack of a market and knowledge of the uses of molybdenum. During World War I it was used as a substitute for some rare metals and for minor chemical purposes. After 5 years of intensive research and sales promotion, Climax metallurgists succeeded in finding proper applications for the newly discovered metal and the mine was reopened in 1924. Demand for molybdenum increased gradually and in 1930, 3.5 million lb of MoS2 were produced. In the meantime, research work for additional uses of molybdenum continued until it had established itself as one of the most important alloying elements in producing high quality steels. After the start of World War 11, from January 1942 to October 1953, 43 million tons of molybdenum ore were mined and 484 million lb of MoS2 were produced. Climax mine is located in Colorado, 100 miles southwest of Denver and 12 miles northeast of Leadville on the Continental Divide of the Rocky Mountains. The principal mine workings range from 11,170 to 12,000 ft in elevation. Topographically, it lies in the base of a large cirque that is surrounded by Mt. Bartlett to the north, Clinton Peak and McNamee Peak to the east and Ceresco Ridge to the south. This cirque opens to the west and to the Ten Mile Valley.

Jan 3, 1954

By R. E. MacAfee

THERE have been great changes in the design, capacity, and pressure of steam generating units over the past fifty years. If we go back as far as 1890, the plants then existing were largely horizontal return tubular boilers, hand-fired, with the boilers supported on the brick sitting which was com-posed of red brick with, probably, a refractory lining one brick thick in the combustion chamber. About this time, the water tube boiler began to supplant the H.R.T. boiler and, where new plants were being constructed of any size, water tube boilers were largely installed. In those days, say from 1890 to 1905, a 250 h. p. water tube boiler was considered a large unit. These boilers were largely the straight tube type and were set with the first row of boiler tubes three to six feet above the grates. The brick setting was a combination of red brick and fire-brick. The fire-brick lining in the furnace proper was usually 9 in. thick and in the first pass 4 1/2 in., while the rest of the setting was entirely red brick. These units were largely hand-fired and were expected to produce about 100 per cent rating as a maximum. It may be well at this point to define rating, which is the evaporation of one boiler horse power per hour by each ten square feet of heating surface in the boiler. A boiler horse power is the evaporation of 34.5 pounds of steam from and at 212°F. Consequently, a boiler containing 2,000 square feet of heating surface is rated at 200 h. p. and the evaporation at 100 per cent rating is 200 X 34.5, which equals 6,900 pounds of steam per hour from and at 212°F.

Jan 1, 1939

Up to 19 chemical parameters were studied in flotation pulps in six Australian lead-zinc concentrators with the aim of obtaining a better understanding of the nature of, and changes in, the chemical environment. This paperdiscusses pH, redox potential, and oxygen concentrations, which were all measured continuously.Two plants operated at natural pH in slightly acid circuit and one at natural pH in alkaline circuit, and pH was stable at all these plants. In two plants varying amounts of cement fill were present in mill feed and pHwas variable. At the other plant pH was controlled with soda ash and lime.Redox potentials became more positive as the pulp passed through the plant. The minimum change was 20 mV and the maximum about 250 mV. Potentials tended to be variable at any point early in the circuit, but were more stable later on. In some plants reagent additions had no noticeable effect on redox potentials. However in the two plants operating in acid circuit the redox potential of .zinc rougher feed was markedly affected by changes in copper sulphate addition rate. Sodium sulphite additions had an effect at other plants.Oxygen concentrations in grinding circuits tended to be low (30 per cent of saturation) and very variable. Flotation was usually conducted in pulps at least 90 per cent saturated with oxygen. Addition of sodium sulphite had a marked effect on oxygen content in one plant, but less effect in two others.Statistically significant relationships were found in some plants between pH and redox potential, redox potential and oxygen saturation, and oxygen saturation and pH.Improved control of copper sulphate and sodium sulphite additions could result from applications of this work.

Jan 1, 1970

1. Book review Economics of mineral exploration in Australia, by Brian W. Mackenzie and Michel L. Bilodeau. Australian Mineral Foundation (Private Bag 97, Glenside, South Australia 5065). 198pp. $A58. $A45 for students. Reviewer: D.G. Krige 2. Recent publications Combustion of coal liquid mixtures, by G.F. Morrison. London, lEA Coal Research, 1983, 52 pp. Hafnium: physico-chemical properties of its compounds and alloys. Vienna, International Atomic Energy Agency, 1981. 408 pp. 620 Austrian schillings. Canadian mines handbook 1984-85, edited by CD. Gardiner. Toronto, The Northern Miner, 1984. 500 pp. $24. Drilling equipment in Canadian mining and exploration- opportunities for the industry, by AJ. Jakubek. Toronto, Micromedia Limited (144 Front Street, Toronto M5J IG2, Canada), 1984. Research report 1984. Port Melbourne, Division Mineral Chemistry, Commonwealth Scientific and Industrial Research Organization, 1984. 190 pp. Surface engineering Wear is an unavoidable problem in virtually all products of the engineering industry, from the minute bearings of instruments to the cutting surfaces of earth-moving plant. Safety in mines About 50 papers will be presented at the 21st International Conference of Safety in Mines Research Institutes at Sydney from 21st to 25th October, 1985. Some 250 delegates from 30 nations are expected to attend. Professional development seminars March 18th-21st, 1985 Underground Blast-hole Mining May Ist-3rd, 1985 Mineral Processing of Gold Ores May 6th-10th, 1985 Mineral Comminution Systems May 13th-15th, 1985 Processing of Metallurgical Residues Analytical chemistry The Second Symposium on Analytical Chemistry in the Mining, Exploration and Processing of Materials is to be held in Pretoria from 15th to 19th April, 1985.

Jan 1, 1985

By G. S. Walker, W. van Bronswijk

The accurate determination of free cyanide and metal cyanide complexes is of increasing interest to Carbon-in-Pulp (CIP) gold extraction operations as cyanide consumption is an important economic factor in the processing of complex ores. Characteristically complex ores are high cyanide consumers and these ores usually contain a range of sulfide minerals e.g. covellite (CuS), digenite (Cu1,S), chalcocite (Cu, S), Pyrrhotite (Feci-x)S), marcasite (FeS2), arsenic and antimony sulfides and zinc sulfide. These minerals can consume significant quantities of cyanide, e.g. various copper(!) cyanide complexes such as CuCN, Cu(CN)2·, Cu(CN)/ and Cu(CN)/ can form, depending on the cyanide to copper ratio in solution. Measurement of free and complexed cyanide is thus a prerequisite for efficient cyanide dosage control. Free cyanide can be determined potentiometrically or amperometrically but the methods are prone to error and are laborious [1]. Metal cyanide complexes can be determined by reverse phase HPLC, however, the species ofa single cation (e.g. Cu(CN)i-, Cu(CN);2 and Cu(CN)/) elute as one species [2]. Additionally the high amount of suspended matter in CIP leach solutions tends to introduce errors. Raman spectroscopy has the potential to be used as an in­line or on-line method of analysis. Free cyanide and the cyanides of gold, silver, copper and iron have been studied in aqueous alkaline solutions with a view to developing such a method. Spectra were obtained with a Bruker RFSl00 FT-Raman spectrometer using a 1064 nm laser delivering 800 mW of power at the sample. Depending on the solution, 250, 1000 or 4000 scans at 4 cm-1 resolution were accumulated. The cyanide stretches observed were relatively narrow (10 15 cm-1 full width at half height) and well resolved (Figure 1 ).

Jan 1, 1995

By Luciano Ramos, Daniel Santos

Igarape Bahia Mine, which is currently the largest gold producer in Brazil, belongs to Companhia Vale do Rio Doce - CVRD and is situated 250 miles south of Belem, state of Para, Brazil. It came into operation in 1992 with the startup of the CIP plant, fed with high grade ore, presently at 3.4gAu/t. The ore is totally oxidized, containing extremely fine particles of free gold. The ore is soft and low cyanide consumer, with a maximum work index of 12kwh/sht. In 1993 a Heap Leaching Plant was set into operation, handling low grade ore of · 1.s g Ault. The Heap Leaching Plant has undergone two major expansions. In 1994 its capacity was raised from lMtpy to 2,2Mtpy and in 1998, with a thorough remodeling of crushing operations, it was raised again to 3.5Mtpy. The CIP plant, which was originally designed with a capacity for l. lMtpy of ore, was expanded to a 2.2Mtpy capacity in 1994. Presently, the CIP plant accounts for most of Igarape Bahia's total gold output, with approximately 220,000oz per year. Igarape Bahia's annual output is around 360.000 oz. Over the last three years, work has been intensified to improve performance of both processes, aiming at maximizing productivity of the two industrial plants. Reduced costs and increased revenues have been given a special emphasis in the unified improvement program. Cost · reduction has involved developing methodologies to rationalize consumption of materials and inputs, while increased productivity has been given top priority as a means of generating increasing revenues. Thus, all of the improvement and development efforts have had a common goal: to increase operating income.

Jan 1, 2000

By R. D. H. Wigmore

"The title of this paper probably sounds quite simple and self-explanatory. The problem, however, was not a simple one, and proved somewhat baffling and expensive over a period of years. After outlining the problem, and the methods which were used to overcome it, we will present our solution, or perhaps it would be more accurate to say the partial solution which we reached.We have in the cyanide circuit at Upper Canada two Dorr Single Tray Thickeners with 30 ft. diameter wood stave tanks 12 ft 4 1/ 2 in. deep. In the years prior to 1948, when the tonnage was 250 to 280 tons per day, two stage thickening was practised. As the tonnage was increased to 450, 500, and finally 560-600 the thickeners were used in parallel.Some settling problems were encountered, and in those days the means to combat these problems were very few. The only remedy was to dump in pounds and pounds of lime. Then along came a few reagents, and the writer remembers one in particular, - 11 Carboxel11 (carboxymethlycellulose). When water or solution was added to this reagent, the result was a gooey mass somewhat resembling tapioca. One drawback was that it stayed in this state, and didn't go anywhere. A method was finally developed of containing the mass (or mess) on a fine screen, and dissolving some of it was a fine spray of solution. The only thing the writer recalls was that it was not a very effective settling agent.Shortly after this time, along came the new flocculents, first a few, and then many, and our settling problems were over.But when the settling problem was solved at Upper Canada, some other problems were creeping up on us."

Jan 1, 1965

By P. Harris, N. Heywood

An existing 1 800 m long pipeline, which carried waste mica slurry from kaolin processing, is to be recommissioned. The mica solids throughput is to be substantially increased from 5.2 t/h up to a maximum of9.53 t/h, but with a typical throughput of around 7.5 t/h. Because of this throughput increase, it was unclear whether the existing 80 mm diameter pipe would be adequate. In addition, the pipe route is to be extended by 250 m to 2 050m, and its elevation at discharge to settling lagoons increased from 66.2 m to 80 m. The pipeline hydraulics of waste mica slurry were investigated for the 80 mm diameter pipe using the Saskatchewan Research Council?s (SRC) Two-Layer Flow Model, for the maximum mica solids throughput of 9.53t/h. The pipe operating velocity was compared with the predicted deposit velocity for several mica concentrations, ranging from 20% to 50% by weight. Estimates were made of the total differential pressure across the proposed2 050 m long pipeline, as well as the power imparted to the slurry by the pump, and the specific energy consumption (SEC). Two pipe diameters were assumed: 80 mm when no mica wall deposit is present, and 70 mm when there is a 5mm mica wall deposit. This parameter has a significant effect on the determination of the appropriate pipe operating conditions. For the pipe operating velocity to remain adequately above the deposit velocity (and therefore for the heterogeneous flow pattern to prevail in either horizontal or inclined pipe), it was concluded that if the newly commissioned pipeline contains no mica wall deposit, the pipe should initially be operated at a mica concentration of between 20% and 25% by weight, probably with a target mica concentration of about 23%. A 23% mica

Jan 1, 2007

The Mount Isa mine in North West Queens- land produces a total of nearly 10 million t/yr from separate copper and silver lead zinc orebodies. Sampling information is mainly obtained from diamond drilling on 30 to 40 metre centers in both types of orebodies. For the copper orebodies the majority of the core is analysed for copper content using a non-destructive bulk analyser developed by the Australian Atomic Energy Commission. The diamond drill core in the silver lead zinc orebodies is usually sam- pled as sawn half core and assayed in the com- pany laboratory using a variety of methods dependent upon the level of metal content and/or the elements required. Underground development is sampled where additional information is required to improve the ore reserve estimate. The copper areas are sampled using a standard 2.0 m by 2.0 m chip sample of the wall. The chips are taken on a 250 mm spacing. Lead areas are sampled using a 100 mm wide by 4 mm deep channel over intervals determined by the area geologists. The massive, irregularly shaped copper ore bodies are mined as large sublevel open stopes and pillars. Ore reserve estimation on both a production unit and global scale is routinely carried out using a geostatistical system developed in-house and running on a Sperry 1100 mainframe computer. Copper grade, tonnes and the Kriging var- iance are estimated at points on a user defined grid. The Kriging program uses 10 m assay composites from diamond drill core and underground chip samples. One average (rela- tive) variogram is used throughout the main copper orebodies. The validity of using an average variogram was verified by the original geostatistical study undertaken in the late 1970's.

Jan 1, 1987

By C. Max Bauer

THE most important development in the petroleum industry in Montana, during 1924, was the bringing in of the Hepp well on May 12, by the Midwest Refining Co. This followed three years of active prospecting and drilling in the state by this company. The well is located 35 miles west of Billings, in Stillwater County, and makes a high-grade paraffin oil from the Dakota sand at a. depth of 3825 ft. After flowing for several months at the rate of 150 bbl. per day, the well has been shut in for lack of storage, awaiting further development in the field. TABLE 1. Production Cat Creek and Kevin-Sunburst Fields Month Kevin-Sunburst Pipe- Estimated Cat Creek Pipeline Estimated line Runs Fuel Oil Used Runs Fuel Used January 3,214 0 133,400 140 February 3,250 0 134,248 490 March 11,989 595 163,129 910 April 116,897 1,155 125,918 980 May 179,726 2,310 152,179 770 June 126,131 2,697 122,270 910 July 132,173 2,170 118,034 770 August 202,001 2,695 142,313 1,120 September 187,201 2,135 110,012 350 October 162,589 1,995 121,683 350 November 130,392 2,520 139,900 350 December 107,465 1,780 124,169 0 Total 1,363,028 20,052 1,581,255 .7,140 There are two producing oilfields in the state-the Cat Creek and the Kevin-Sunburst, which produced a total of 2,971,475 bbl. in 1924. The only other field of proved value is Soap Creek, which contains a heavy black oil and is shut in for lack of marketing facilities. Gas is produced for local use at Havre, Chinook, and Baker, and a carbon-black plant is located at Baker.

Jan 3, 1925

By Thomas Schemmel, Bertram Kesseiheim, Helge Jansen, Uwe Kreme

"During the last decades the refractory life time of the different aggregates of the secondary aluminium production was improved significantly. However, each repair and installation of refractory material affects the operating schedule and can cause costs in the million range. The downtime of just one melting furnace generate costs of 100.000 to 400.000 $ per day. Besides cooling down of the furnace and its repair, the heating-up procedure accounts for the longest time of the shutdown. Usually, heating-up of low cement or ultra low cement castables takes 120 to 150 hours. In order to reduce such expensive downtimes Refratechnik developed a unique and novel product series: Nanobond. These materials can be heated-up in only a third of the usual time. This paper talks about the theoretical aspects, as well as the mechanical and physical properties and especially practical experience of using Nanobond.Theoretical Aspects and Laboratory ResultsCement containing castables such as RCC, MCC, LCC or ULCC are considered standard in many refractory applications. Over the years a wide range of possible raw materials and practical installation methods were developed. However, all of these cement bonded refractory mixes possess one main important drawback. Such materials are characterized by the hydration of the cement bonding. As a result the physical bonded and the hydraulic water has to be removed in a relatively complicated drying procedure. The hydraulic water specifically demands a very careful and cautious heating up procedure. Most of the dreaded steam explosions can occur at a furnace temperature of approx. 250 oC. [1] To avoid such destructions, the heating-up of a new lined or repaired furnace can be very complex and slow. Depending on the furnace or the casted part a drying time of several days with long curing times are common."

Jan 1, 2012

By V. E. Suter

Anyone with geothermal experience can readily attest that geothermal operations are a natural extension of oil and gas operations. A geothermal company and an oil company need the same type of people to do the same kind of work. In the geothermal industry, geologists and geophysicists define prospects through surface geology, analysis of surface seeps, magnetics, gravity, and resistivity surveys - techniques similar to those used in the petroleum industry. In addition, shallow (250-ft) temperature gradient holes often are used in geothermal operations. Landmen take geothermal leases that are patterned after oil and gas leases. Exploratory drilling is done with the same drilling contractors and same drilling rigs, with minor modification. Drilling foremen and drilling engineers share the same objective of making the most hole, in the shortest time, at the least cost, with a proper completion. Petroleum engineers test the wells, design the completions, determine the reserves, make economic calculations, work with the tax assessor, and manage the reservoirs. Production engineers build roads, locations and pipelines, install gas/liquid separators and meters, and operate production and injection facilities. A contract to sell steam to a public utility is required. Various governmental regulations, permits, environmental concerns, and public affairs pose similar problems in both industries. Also required of both are top management people who are acquainted with geologic risk, prepared to accept million dollar dry holes, willing to bid competitively at lease sales, and able to invest large sums based on a technology not yet fully proven. Successful geothermal development requires in-depth financial ability similar to that required for petroleum development. A high capital investment is required early for leases, geological and geophysical work, and exploratory and confirmation drilling. After

Jan 1, 1980

By D. Turnbull, A. M. Turkalo

It is well known that if copper that has been severely cold-worked by rolling (70-98 pct) is heated to high temperatures a small number of large grains are formed at the expense of the fine grained structure that appears upon primary recrystallization. Dahl and Pawlek,' Cook and Mac-Quarie,2 Ward,3 and Boas and Bowles4 have studied this phenomenon in copper. It has been reported as taking place with measurable velocities in the temperature range 700-1080". Boas and Bowles have reported that the time necessary for the transformation is of the order of days at 700°C. According to Ward3 the number of secondary grains which appear in OFHC copper decrease with increasing perfection of cubical alignment after primary recrystallization; also the perfection of cubical alignment increases with decreasing grain size prior to the final reduction. In this investigation two heats, A and B, of especially high purity copper (99.999 pct) supplied by the American Smelting and Refining Co., were used. The behavior of samples prepared from the two heats was qualitatively very similar providing that the grain sizes established prior to the final reduction were about the same. We observed that in specimens prepared from bars which were relatively coarse grained prior to final reduction secondary recrystallization took place at a rapid rate at temperatures as low as 500°C. This is about 200-300°C lower than the temperature necessary to obtain fairly rapid transformation in OFHC copper. A 0.22 in. thick rectangular bar of lot B was cold-reduced 60 pct by straight rolling and given a penultimate annealing treatment at 250°C. Following this it was cold-reduced 90 pct and heated to various temperatures in the range 450-1040°C. The specimens were about 8 mils thick

Jan 1, 1950

By George A. Bell

THE mine and milling plant of Demonstration Gold Mines, Ltd., is near the city limits of Baguio, Mt. Province, P. I. The mine road connects with the main highway to Manila. The nearest railway point is near sea level, approximately 40 miles distant. The Baguio district is very mountainous and has one of the heaviest rainfalls in the world. It is therefore difficult to maintain roads or to impound tailings and mine dumps. All supplies are trucked into the district direct from Manila or the nearest railway point, which means uncertain deliveries and high freight rates. Installation of equipment is difficult and costly. The average elevation at the mine is 4000 ft. and the climatic conditions are ideal except for a three months rainy season. The company generates its own power for mining and milling operations with three 400-hp. Ruston Diesel engines direct connected to 250-kw. General Electric alternating current generators. Labor conditions have been excellent, although at present social security laws are causing some unrest. Labor receives a higher average wage rate in this district than other labor in the Islands. The company also furnishes free living quarters, hospitalization and work- men's compensation. Taxation has been reasonable up to the present time, but some of the new mining legislation may make it difficult to operate and pay dividends. The future depends largely upon the continuation of $35 gold and the political outcome in the Islands. HISTORY The Demonstration ore body was worked by the Igorots for many years, as evidenced by old stopes and fill encountered in present operations. Attention of Americans was first attracted soon after the Spanish- American war. During the building of the Benguet road to Baguio, the engineers and foreman became interested in the geology of the district.

Jan 1, 1939

By A. J. Weinig

The Liberty Bell cyanide precipitate is unique in that it is apt to vary widely in composition in the course of very short periods of time, and a method of refining and melting that would prove highly satisfactory at one cleanup would yield7almost a hopeless "mess" at a second. Table I gives a general conception of the wide range in grade and composition of those raw precipitates. It is evident that no one standard flux could be expected to produce a high-grade bullion with such a widely variable precipitate, and that any method of treatment with acid requires most careful consideration. Refining by Acids Naturally, our first efforts to improve our precipitates were directed along the lines of acid treatment. Table II embodies the results of careful sampling and analysis of one cleanup at the time when wet refining reached its maximum development at this mill. We have now discarded all methods of wet refining, successfully replacing them by a more scientific method of flux calculation described herein, but it is believed that a general description of this wet refining is warranted as it throws some interesting side lights on acid refining in general. Table I.—Range of Composition of Raw Precipitates Per Cent. Gold and silver.................................... 25.0 to 75 Zinc.............................................. 18.0to 30 Lead............................................. 0.5 to 52 Copper........................................... 0.5 to 20 Silica............................................ 1.0 to 5 Calcium oxide...................................... 4.0 to 8 Sulphur.......................................... 0.5 to 8 Column A gives the analysis of the raw precipitate; column B, that of the precipitate after heating with steam, with frequent addition of hydrochloric acid until a point was reached where the batch had a strong tend-

Jan 1, 1917

By Howard S. Bryant

The year 1928 has recently.passed from the picture and it is at this time that the various divisions of the oil industry are giving thought to plans for the present year. The outstanding characteristic of the industry in 1928 was the successful curtailment of oil production to the market's needs. It has been thought advisable to look ahead and endeavor to anticipate the oil demand for the coming year, and thus determine the volume of oil that can be safely produced without causing major additions to surface stocks. The year has been one of smaller additions to stocks than in 1927, a record demand for oil products, and a further developed spirit of cooperation among oil producers, as well as various other achievements. It is well to pause and take stock of ourselves. Present Status of Crude Oil Supply and Demand The total daily new supply of oil is at this time1 about 2,960,000 bbl. per day, made up of 2,585,000 bbl. domestic crude production, 125,000 bbl. casinghead gasoline, and 250,000 bbl. of imports. With the present low consumption, due to the falling off in the winter season demand, it is estimated that about 150,000 bbl. a day are now being run to storage, and that the first three months in 1929 will see large-sized additions to storage. Consumption plus exports of oil have increased at a regular rate from year to year, and although oil production in 1928 passed the 1,000,000,-000 bbl. mark for the second time in the history of the United States, with a production of 25,000,000 bbl. more than in 1927, only 30,000,000 bbl. were added to storage during 1928. This is compared to an addition of 65,500,000 bbl. in 1927.

Jan 1, 1929

By L. H. de Wald, J. Walter Scott

It is usual practice in the copper industry to use open horizontal molds for casting tough-pitch copper wire bars.' A wire bar cast in this manner is partly characterized by heavy wrinkles and a comparatively deep skin of oxide on the top of the bar, corresponding to the open side of the mold. On the theory that the rough, high-oxide surface might have an adverse effect on the rolling and drawing properties of a wire bar and might account for some of the irregularities of mill behavior, several bars which had been planed to remove the wrinkled surface were processed into wire. These bars responded to mill treatment more satisfactorily than did the regular wire bars. Realizing that machining the surface of one face of each bar would not be commercially feasible, it was decided that casting the metal into a vertical mold and cropping off the pouring end would accomplish approximately the same result. Several wire bars of commercial size (250 Ib.) were so cast and processed into wire for comparative test with bars cast in the usual horizontal molds. It is the purpose of this paper to present the results obtained from this investigation, in which commercial bar sizes and processing technique were used throughout. The results show that in general copper wire bars cast vertically are superior to those cast horizontally. Experimental Procedure A horizontally cast bar and a vertically cast bar were obtained from each of several regular reverberatory furnace heats of copper which had been refined and poled to tough-pitch metal in accordance with usual methods.' Both bars were cast from the same part of the melt and within five minutes of each other, in order to produce as nearly as possible, in each case, wire bars of identical composition.

Jan 1, 1930

By E. C. Dominguez, H. B. Scharf

THE Sparrows Point plant of Bethlehem Steel Co., southeast of Baltimore, is the largest Bethlehem plant, with an annual rated capacity of 6.2 million ingot tons. There is considerable diversity of product, but a high percentage is sheet, tin plate, galvanized sheets, and rod and wire. The large amount of light-weight end product requires a number of pickling installations that necessarily consume large quantities of sulfuric acid. In the coking operations sulfuric acid is also consumed in recovery of ammonia as ammonium sulfate and in treatment of recovered light oil derivatives. Total sulfuric acid consumption in the plant is currently approaching 10,000 tons per month, of which 55 to 60 pct is required for pickling. In 1951 the acute sulfur shortage caused grave concern as to future sulfuric acid supply for the Sparrows Point plant. Raw materials for acid making were already at hand in the form of hydrogen sulfide and pyrites sufficient to produce nearly half the sulfuric acid required at that time. It was also known that the Bethlehem mining activities would produce additional pyrites in the future. Late in 1951 Bethlehem management decided to build a 250-ton sulfuric acid plant at Sparrows Point to utilize these raw materials. The plant was built and put in operation in May 1953. The steel plant has expanded considerably since 1951, and it is now necessary to operate the acid plant far over rated capacity in order to supply plant demand. Production of acid in 1954 amounted to 93,000 tons. Raw Materials for Acid Making: Coking operations at Sparrows Point produce a residual fuel gas in large quantity which has a net heating value of 525 to 545 Btu. Prior to 1950, plant surplus coke oven gas was sold to the local utility company. In

Jan 1, 1957

By A. E. Harnsberger

IT is obvious that details such as the physical and chemical properties and methods of heat-treating of the materials mentioned must be omitted in a paper on the subject of materials used in oil-refinery pumps1. Only sufficient identification is given to enable the reader to find additional information from already published data. Also, the subject covers many operating conditions, but only the most important services can be discussed here. To the oil refiner, the pumping equipment is of vital interest. Practi-cally every refinery operation, from the charging of crude oil to a dis-tillation unit to the shipping of refined products, involves some form of pumping machinery. Intermediate refining stages involve a great variety of pumping machinery to carry out successfully the aims of the refinery technologist. Temperatures at which oils are handled vary from -50° F. to 900° F. Pressure may vary from subatmospheric to 2000 lb. per, sq. inch. The selection of the proper materials involves a careful consideration of the conditions under which the particular pump must operate. The four most important considerations are temperature, pressure, corrosion, and abrasion or wear. Consideration of temperature may be divided into three parts: (1) extremely low temperatures of the order of -50° F.; (2) temperatures at atmospheric or slightly above; (3) temperatures from 200° to 900° F. Pressures fall into two groups: (1) pressures reached by ordinary trade pumps of the order of 200 lb. per sq. in., (2) extreme pressure conditions involving pressures as high as 2000 lb. Noncorrosive and corrosive oils can be treated differently. Under the latter falls corrosion in the presence of water, which will occur up to 250° F. The second type of corrosion occurs in high-temperature pump-ing equipment, with temperatures from 450° to 900° F., largely caused by sulfur compounds. There are also other corrosive conditions met with

Jan 1, 1935

The Telfer main dome open pit is operated by Newcrest Mining Limited at a current production rate of 50 Mt/a from a pit dimension compromising 2 km strike length, 1 km width and 250 m depth. As part of the refeasibility of the Telfer operation undertaken early this decade, Newcrest identified that an underground sublevel cave (SLC) operation along with an increased scale of open pit would support a new plant targeting the processing of gold and copper ore at 17 Mt/a rates. The SLC was initiated in late 2006 and broke into the open pit in late 2009. This situation is unique across the mining industry where a cave breakthrough was planned and occurred within an active large open pit operation. The SLC broke though into the west side of the Main Dome open pit into a specially prepared bench that was left at the 5384 RL of cut-back stage 3. A main haulage ramp is within 100 m from the edge of the cave breakthrough zone and this ramp passes down to the active levels which are progressing toward the 5200 RL. This paper presents insight into the mine planning and risk management associated with continued operation of the open pit operation while an active SLC breaks through. The cave breakthrough presents unique areas for risk management as there is potential for rapid propagation and subsidence. To support the undertaking, mine design and major hazard management planning has been carried out. Focus areas include; dual ramp system design, preloading the breakthrough area, monitoring of cave propagation and air gap using a seismic system and deep hole extensometers, wall stability and subsidence monitoring using radar and prism systems, and key trigger and response planning.

May 1, 2010