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By Brad Bjornson, Geoff Stevens, Mike Ashar, Cliff Britch

"LocationThe facilities are located 30 km north of Fort McMurray, Alberta (or 470 km northeast of Edmonton, Alberta).Brief Description of OperationThe operation includes the mining of oil sands, extraction of bitumen from the oil sands, and upgrading of the hydrocarbon fraction prior to shipment via pipelines to refineries.HistorySuncor was initially called Great Canadian Oil Sands. It was started by Sun Oil of Philadelphia. Construction began in 1965, with the first production coming on September 1967.Details of Present Milling Practice (Plant 3)Plant 3 recovers bitumen from the oil sand using the Clark hot water process. The basic steps in the process are conditioning, primary recovery, secondary recovery and tailings oil recovery.Oil Sand Feed SystemThe oil sand feed from the mine is transferred to the feed bin in extraction by two conveyor systems. Oil sand analyzers on each conveyor system measure the amount of bitumen and fines in the ore. Cones at the bottom of the feed bin distribute the oil sand to five process lines. Feed flow from each cone is regulated by an apron feeder which transfers the oil sand to conveyors that discharge into the conditioning drums. Weightometers on each of these five conveyors measure the rate at which the oil sand is delivered into the drums. The oil sand feed rate to each drum can be adjusted by varying the speed of the apron feeders."

Jan 1, 2000

The Shortage of Mining and Metallurgical Engineers I N many parts of the Western World attention has recently been drawn to the acute shortage of mining and metallurgical engineers produced by the universities. Naturally, the reasons for this shortage have been discussed, and various remedies for it have been proposed. In this paper, I want to examine some of them. It is now fairly generally ac-cepted among mining men that the easy attractions of modern urban life have left the career of mining in the metaphorical as well as in the literal backwoods. The industry finds it increasingly difficult to recruit adventurous and intelligent young men; for such men now seek their intellectual, if not physical, adventure in more glamorous occupations from a safe social base in suburbia. The salaries, opportunities and security offered by the mining industry do not complete effectively with the rewards offered by other industries and by commerce, taking into account the social disadvantages of a mining life. The excitement and other non-material attractions of mining

Jan 1, 1965

By Lyle F. Smith

With the demand for larger diameter raises under all ground conditions and the increasing price of drill rods and operating costs, it was evident that there was a need for a raise borer with a variable-speed drive and fast-response torque limiting control. The raise boring machine described in this paper was developed after several years of market research and discussions with mine operators and construction contractors. This paper discusses the Ingersoll-Rand raise borers with the solid-state controlled DC motor drives. These machines have gained wide acceptance in the five-year period since being placed in operation and are designed to accommodate the range of raise diameters and lengths most required today.

Jan 1, 1978

By G. H. Agnew

When water floods are initiated after gas-oil ratios have increased, the transition period from the start of injection until" the gas-oil ratios are returned to the solution gas-oil ratio may be important for either economic or technical reasons. The transition period is longest, and consequently most critical in water floods where injection is equal to withdrawals. This paper describes a theoretical basis for predicting the behavior of such a system and outlines a procedure for making the necessary calculations. The calculation procedure is illustrated for two actual cases: a line drive water flood and a five spot water flood. In each case there is a reasonable similarity between the actual and calculated performance.

Jan 1, 1960

By The Mill Staff

"IntroductionCOMMENCEMENT of operations at the new No. 7 shaft and 10,000-ton mill at Creighton mine was a major step in the programme of conversion to all-underground mining by the International Nickel Company of Canada, Limited. Planned ten years ago, the orderly transition has been greatly speeded-up to offset the heavy drain on production imposed by World War II and also to meet the increased demand for nickel caused by the current international situation. Development of new mining methods, and process changes in the reduction plants, have made possible the economic recovery and utilization of ore of lower grade than formerly used and of varying metallurgical characteristics. By 1953, when the Company's open-pit mining operations are scheduled for completion, the hoisting capacity of its five underground mines in the Sudbury district will have been increased to 13,000,000 tons per year, compared with 5,700,000 tons of underground ore hoisted in 1950.Two types of ore occur at Creighton. One is a breccia and stringer type that contains a high percent-age of massive sulphides and is located in sheets along shears and in large and small pockets on the underside of the main norite mass; the other type, forming the main part of the ore zone, is mineralized norite that occurs as a •sheet up to 400 feet thick overlying tl1e breccia ore. In both types of ore the minerals of economic interest are pentlandite, which is intimately associated with pyrrhotite, and chalcopyrite. Early mining was confined to the breccia ore; this ore was mined by open stoping methods. The hanging-wall was later allowed to cave, with the result that the old stopes are now filled with caved low-grade ore."

Jan 1, 1952

By M. Turner-Jones, N. Steenekamp

"The Lonmin Base Metal Refinery treats converter matte from the Lonmin Smelter to produce nickel sulphate crystals, copper cathode as well as a concentrate containing the platinum group (PGM) metals. The original process employed a Sherritt design and utilizes atmospheric and pressure leaches for the dissolution of base metals. This paper describes the original flow sheet and the improvements made to enhance PGM recoveries, product quality and to increase capacity. Changes include the introduction of flash recycle cooling on the autoclave, batch leaches to improve the quality of the PGM concentrate and the implementation of solid-liquid separation with centrifuges. INTRODUCTIONThe Lonmin Base Metal Refinery (BMR) is about 100 km north-west of Johannesburg and treats converter matte from the Lonmin Smelter to produce nickel sulphate crystals, copper cathode and a concentrate containing the PGMs. The plant was commissioned in 1985 based on a Sherritt design to treat 12 tonnes converter matte per day. The original flow sheet consists of a milling circuit, an atmospheric leach and a pressure leach to produce a PGM concentrate which is despatched by helicopter to the Lonmin Platinum refinery in Brakpan, about 40 km east of Johannesburg. The liquor from the atmospheric leach is treated by crystallization to produce a nickel sulphate hexa-hydrate crystal. The leach liquor from the pressure leach is treated by a selenium removal step followed by electro-winning to produce copper cathode. The spent solution from the copper electro-winning is recycled to both the atmospheric and pressure leach steps to provide sulphuric acid for the leaching reactions.Modifications were made to the original circuit to increase the plant capacity, to improve the PGM recoveries and to improve the quality of the PGM concentrate. Capacity increases included all the unit operations, new mill, new first stage, additional autoclaves, additional nickel sulphate crystallizers, new copper electro-winning and new batch leach reactors for upgrading the PGM concentrate. The current circuit is described in this paper and not the detailed history of each plant change."

Jan 1, 2012

By B. Panton, J. Carvalho, E. T. Brown

High-capacity, post-tensioned anchors have found wide-spread use in initial dam design and construction, and in the strengthening and rehabilitation of concrete dams to meet modern design and safety standards. Despite the advances that have been made in rock mechanics and rock engineering during the almost 80 years in which post-tensioned anchors have been used in dam engineering, some aspects of the rock engineering design of high-capacity rock anchors for dams have changed relatively little over the last 30 or 40 years. This applies, in particular, to the calculations usually carried out to establish the grouted embedment lengths required for deep, post-tensioned anchors. These calculations which involve a number of aleatory and epistemic uncertainties, usually make simplified assumptions about the distribution and values of rock-grout interface shear strengths, the shape of the volume of rock likely to be involved in uplift failure under the influence of a system of post-tensioned anchors, and the mechanism of that failure. The resulting designs are generally conservative. These aspects of the rock engineering design of large, post-tensioned rock anchors for dams could be improved by making greater use of modern, comprehensive, numerical analyses in conjunction with 3D models of the rock mass structure, realistic rock and rock mass properties, and the results of prototype anchor tests in the rock mass concerned.

Jan 1, 2015

Iron control and iron residue management and disposal are significant issues in all zinc production processes. This paper briefly reviews the most important primary zinc production routes and discusses the challenges posed by iron control in each of them. The technologies and strategies that have proven successful in controlling and managing iron are discussed. SNC-Lavalin's experience in designing and commissioning zinc plants provides a unique perspective from which to review this aspect of zinc production.

Jan 1, 2006

By A. Ehsani

"Seas and oceans constitute about 70% of the earth’s surface. They contain an enormous stock of various mineral resources such as sedimentary (marine placers), massive sulfide ore deposits, manganese nodules and cobalt-rich ferromanganese crusts. Sea and ocean floor ore deposits could well contribute to the meeting of ever-rising demand for raw materials in the metal industry. In this regard, more research and development in science and technology appear to be required to ensure maximum benefit from the mineral resources of seas and oceans. Since the 1960s, a variety of mineral and metallurgical processes have been studied and developed to deal with marine ores and to extract metals such as gold, nickel, copper, cobalt, manganese, tin, platinum group metals (PGM), zirconium, thorium, etc.In marine environments, there are many parameters which can affect the selection of the mineral and metallurgical processes. These include the extent and grade of the deposit, mineralogical and chemical properties of the deposit, and physical properties of minerals present with particular reference to particle size distribution and mineral liberation size.In this paper, we briefly review the latest trends in processing and extraction of marine mineral resources. Mineral processing technology is mostly applied for recovery of precious metals i.e. gold and PGM, in particular, from marine placers. In general, pre-treatment (sizing, classification, dewatering), gravity concentration techniques (shaking tables, spirals, jigs, etc.,), flotation, magnetic, and electrostatic separation are the options for enrichment of marine placer ore deposits. In the case of massive sulfides, manganese nodules/cobalt-rich crusts, hydrometallurgical and pyrometallurgical methods (as proven technological methods) can be exploited for extraction of metals from concentrates after physical separation or directly from marine ores. The hydrometallurgical treatments involve acid (e.g., sulfurichydrochloric) and alkaline (e.g., ammonia) leaching with different reducing agents and pre-treatments such as roasting. Alternatively, pyrometallurgical treatments involve mostly smelting, chlorination and segregation processes."

Jan 1, 2016

By M. Gyenge, O. F. Coates, K. Barron

"It is suggested that artificial supports might be used to increase, with safety, the angle of hardrock open-pit slopes. Guidelines for designing such a support system, based on a simplified analysis, are given. The installation, construction and instrumentation of a trial support system is described and a breakdown of the construction costs is given. On the basis of this cost analysis, the economic benefits derived from reduced waste-rock excavation are compared with the support costs for a typical mine. In an example, it is shown that the slope angle in an open-pit mine 500 ft deep, with benches 50 ft high by 30 ft wide, could be safely increased from 37Yz degrees without support to an optimum of 53 degrees with support. In this case, the support costs would be approximately $900 per linear foot of pit wall and the savings due to decreased excavation of waste rock (at $0.34/ton) would be approximately $1,900 per linear foot, yielding an increased margin of profit of approximately $1,000 per linear foot of pit wall. This figure could be increased to $6,000 per linear foot if the steeper slope were used to extract more ore.More than 50 per cent of the support costs are accounted for by diamond-drilling the holes for the deep cable anchors. The use of percussion drills for this purpose would seem to offer a means of significantly reducing the support . costs and thus further increasing the profit margin available."

Jan 1, 1971

By Mohamad Kharseh

There is general acceptance that climate change, which is the most important challenge facing humanity, is anthropogenic and attributed to fossil fuel consumption. Therefore, improving the performance of our existing energy systems and deploy more renewable energy resources is an urgent issue to be addressed. Geothermal refers to existing of heat energy in deep rock and sedimentary basins. This energy can be used to drive a power turbine to generate electricity. Traditionally, geothermal has been exploited in places with the plentiful hot water at relatively shallow depth. In the light of fact that ground temperature increases with the depth everywhere on the Earth, engineered geothermal systems (EGS) can be installed in any place to exploit the geothermal in generating energy. Unfortunately, the high exploration and drilling costs of boreholes is the main barrier to commerciality of EGS worldwide. In addition, there are technical problems associated with drilling big depth. In oil producing countries such problems can be addressed by utilizing whether active or abandoned oil or gas wells and, consequently, EGS can produce power at profit. The current study presents an analysis of a binary geothermal power generation system for commercial electricity generation in Qatar. For this purpose, two binary cycles are assumed the main difference between them is that the first one is air cooled while the other will be water cooled. The performance of the two cycles and the possibility of improvement has been shown. Economic analysis the power plant shows that the levelized costs of electricity is 3.6US¢/kWh and the pay-back time is less than 8 years.

Aug 1, 2013

By D. C. Fraser

Copper occurs invisibly in a geo-logical environment characterized by swampy conditions and an accumulation of forest peat. This swamp, located in southeastern New Brunswick, contains up to ten per cent cop-per (dry weight), in the organic sediments. This occurrence appears unique in that the metal is apparently organically combined in a chelate compound. Unlike the acidic nature of most peat bogs, the pH of the cup-riferous peat is nearly neutral. Analyses of the peat and associated soils have indicated that the bulk of the copper is contained in the organic sediments. It appears that the cop-per distribution is affected by capillarity, evaporation and the growth of frost crystals, and that the copper fixation is effected by organic sequestration resulting in the metal being bound to the nitrogen or oxygen components of the forest peat. While such a fixation mechanism is not definitely established as responsible for the immobilization of the metal, the facts at hand are compatible with

Jan 1, 1961

By Bennett McLaughlin

The Penna Shaft is the deepest single?lift shaft in North America. AGNICO-EAGLE started sinking the Penna shaft in 1995 with a hoisting plant capable of hoisting 1 800 tonnes per day from a 2 240-metre deep shaft. Exploration success at depth lead to the replacement of the existing double drum hoist by another double drum hoist capable of hoisting 7 000 tonnes per day. The use of another double drum hoist, instead of a Blair Multi-Rope winder, to hoist 24,5-tonne skips was only made possible by lowering the safety factor. This paper describes recent experiences at Penna and in South Africa, and examines the possibility of extending the double drum hoisting system to a depth of three kilometres.

May 1, 2003

By J. L. Miller, R. W. Burns

This paper sets out the various phases of bringing a merchant bar mill into operation from feasibility consideration through financing, design and scheduling to completion.

Jan 1, 1967

By E. Engelbrecht

"A pressure non-oxidative leach is employed at Anglo American Platinum Base Metal Refiners to extract nickel from a slow cooled matte. The design base requires two 80 m3 autoclaves in parallel to achieve a nickel extraction of 60% at the nameplate capacity of 32.4 ktpa nickel plated. Isothermal modelling of mineralogical and chemical concentration profiles, through a reactive mass balance, permitted rate constant parameter estimation and selection of the most probable reaction pathway. The model was validated with plant data up to a capacity of 26 ktpa Ni plated and suggested by extrapolation that nameplate capacity may be viable through one 80 m3 autoclave.INTRODUCTION Anglo American Platinum Base Metal Refiners is situated on the outskirts of Rustenburg in the North-West province of South-Africa. The refinery produces nickel cathode, copper cathode, cobalt sulphate powder, covellite rich copper pressure leach residue and bulk sodium sulphate through an integrated circuit that refines slow cooled converter matte. The converter matte is milled, non-magnetics are separated as solid nickel copper matte (NCM), and the magnetics are leached yielding a pressure vessel liquor (PVL). The remaining solid platinum group metals (PGM) concentrate after leaching is sent for downstream processing in the Precious Metals Refinery (Hofirek & Kerfoot, 1992). The work presented here is applicable to the base metals refinery which receives the two base metals feed stocks NCM and PVL. In 2009 the capacity of the refinery was upgraded from 21 ktpa nickel cathode plated to 32.4 ktpa. This paper deals with evaluating the capacity of the pressurised non-oxidative nickel leach (NOX) process which accounts for at least 28% of the nickel leached from NCM by design. The NOX design base requires two 80 m3 autoclaves divided into four compartments operated in parallel at 155°C and 600kPa(g). Elevated temperature is required to speed up the leach kinetics of particularly nickel and iron which are trapped in slow leaching mineralogical phases namely millerite and bornite, (Dinham, 2006). The stated equivalent capacity for the NOX configuration was 32.9 ktpa nickel plated at first pass nickel and iron leach efficiencies of 60% and above 80% respectively and is a key step for the selective removal of iron (Bryson, Hofirek, Collins, Stiksma, & Bereaowsky, 2008)."

Jan 1, 2017

By Claude Hubert, Robert Sansfaçon

"The Malartic gold camp includes the Malartic Gold Fields, Barnat, East-Malartic, Canadian Malartic and Sladen mines. From 1935 to 1984, these mines have yielded 212 403 kg of gold. They occur within a 900 m wide belt of highly sheared, dislocated and faulted volcanic and sedimentary rocks (Piché and part of the Pontiac groups) herein named the Malartic Tectonic Znne (MTZ). The zone trends WNW-ESE and separates two lithotectonic sedimentary domains, the Cadillac to the north and the Pontiac to the south. The sedimentary domains are characterized by their coherent fold generations consisting of open to tight reclined and recumbent F1 folds that have been refolded into series of asymmetric upright F2 folds. A flat-lying schistosity (S1 ) and a vertical pressure-solution cleavage (S2) are ubiquitous throughout. Discrete sets of brittle and brittleductile faults are synchronous and parallel to each of these two fabrics.The MTZ trends N320° in the northwestern sector of the town of Malartie, changing to N2800 at its easternmost extremity. The Malartie and Sladen faults constitute its northern and southern boundaries respectively. These two faults also bound another set of faults oriented N305°. Throughout the MTZ, the faults at N280° and N320° and those at N305° outline a series of anastomosed motifs that constitute the principal structural feature of the Malartic district. Locally, a fourth set of minor faults at N065° combines with the other three prominent sets. All these faults have disrupted the gold-bearing volcanic, sedimentary and intrusive rocks encountered throughout the MTZ.The MTZ comprises numerous lozenge-shaped blocks of komatiites and basalts or greywackes and black shales which are cut by disjointed dikes, sills and small intrusions of felsic and mafic rocks. The latter includes gabbro, diorite, lamprophyre, monzonite and pegmatite. They frequently fill conjugate sets of fractures. In some areas, they are clustered into coalescent intrusions. The present morphology of these intrusive bodies( cube, chocolate-tablet boudin, parallel epiped and cigar) is not representative of their primary forms but the result of late shearing and faulting indicative of a major tectonic event subsequent to their emplacement. The intrusions were injected during a brittle stage of deformation related to the F1 folding but prior to the development of the F2 folds and subsequent tearing and shearing by late brittle and brittle-ductile faults . The ultramafic and mafic rocks are intensely altered to serpentine, tremolite, actinolite, carbonate, biotite, hematite and pyrite according to the nature of their proto/it h. In the vicinity of the MTZ, all lithologies exhibit mineral assemblages indicative of the upper greenschist or lower amphibolite facies of metamorphism.The structural evolution of the MTZ involved superimposed folding, shearing, transposition, mylonitization, brittle and brittle-ductile faulting. Each lenticular motif results from the combined effect of conjugate sets of shear zones that outline lozenge-shaped blocks where strain markers indicate different strain states from cores to margins. Bedding in ultramafic flows and/or sedimentary rocks is either NW-SE or NE-SW within the blocks but, in the vicinity of the Malartie and S laden faults, it has been rotated to become subparallel to the faults.Ore shoots are most commonly associated with altered and deformed bodies of diorite and monzonite, or some mafic and ultramafic schists and, at the Canadian Malartic, Sladen and East Malartic mines, with metasedimentary rocks. The shoots occur in close proximity to the various faults of the MTZ but the gold itself is intimately associated with pyrite, biotite and carbonate in halos bordering fractures crisscrossing the different host rocks. The density of fractures and the width of their altered zones have been significant parameters in the production of economic ore shoots. Grains of gold are visible in some veins of quartz a"

Jan 1, 1990

By H. Jung

The microstructures and grain sizes of nanocrystalline Co and Co-1.1 wt % P alloys were characterized by X-ray diffraction. The corrosion properties of as-deposited and annealed Co-l.l wt % P alloys and pure nanocrystalline Co were studied in a deaerated 0.1M H2SO4 solution using electrochemical measurements and XPS surface analysis. Potentiodynamic polarization testing and impedance measurements revealed that an addition of P to pure nanocrystalline Co improved the anodic-corrosion resistance, however, this enhanced corrosion resistance was compromised by the heat treatment process at 350 and 800°C. The corroded surface of annealed nanocrystalline Co-1.1 wt % P at 350°C exhibited a more porous P-enriched layer compared with the as-deposited case. A sample annealed at 800°C corroded uniformly showing second-phase precipitates. The enhanced corrosion resistance of as-deposited nanocrystalline Co-1.1 wt % P was attributed to the elemental P on the surface that acted to hinder the anodic dissolution kinetics of surface Co following an initial selective dissolution of Co. However, at a higher anodic overpotential region, the superior corrosion resistance of Co-l.l wt% P alloys did not last because of the formation of a non-protective surface film consisting of mainly hypophosphite and phosphate as well as elemental P.

Jan 1, 2005

By R. Stach, S. Gola, P. Zgrzebski, K. Soroko

"At the moment climatic conditions are a primary problem of the exploitation of copper ore. The efficiency of preventive actions in order to improve climatic conditions is connected with the knowledge of changing air in underground excavations. This article demonstrates the analysis of types of ventilation dams which are used in sealing abandoned areas on the maintenance of climatic working conditions in excavations has been conducted at the exploitation in Polish copper ore mines. INTRODUCTION The basis for mining activity performed by KGHM Polska Miedz S.A. is mining copper ores from the deposit lying at depths between 600 and 1,200 m below ground level. Activity has continued since 1963. The copper ore deposit is mined in ‘Lubin’, ‘Rudna’ and ‘Polkowice-Sieroszowice’ mines, where difficult climatic conditions occur. The major factor moulding the climatic conditions in headings is the original temperature of rocks, being the result of geological conditions of the lying of the deposit and the existing geothermal degree. In the faces of present opening-out and preparatory headings, driven from mining areas of ‘Rudna’ and ‘Polkowice-Sieroszowice’ mines in order to open out deeper parts of the deposit, the original temperature of rocks reaches 45°C. Excluding the original temperature of rocks, the following are additional factors affecting the deterioration in the climatic conditions: • thermal properties of deposit rocks, • employed room-and-pillar mining systems, which are characterised by a large surface of exposure of rocks, • using self-propelled mining machines with diesel drive, • a high concentration of mining works, • setting up high-power electrical equipment in headings, • complex structures of mine ventilation networks, • a limited number of ventilating shafts, • constantly longer air-transport routes, • a significant accumulation of water increasing the humidity of supplied air. According to the valid Polish provisions (§21, 2013), the primary criterion of assessment of a climatic hazard is the occurrence at a workstation in an underground mining heading of an equivalent climate temperature of more than 26°C, which temperature is determined according to the following dependence:"

Jan 1, 2019

By V. G. Papangelakis, G. A. Moldoveanu

"Rare earths adsorbed on clay minerals are easily recovered via ion exchange during leaching with inorganic monovalent salt solutions. The leaching efficiency of various salts at 0.5M and 25°C was investigated as a function of cation type and salt system (sulphates vs. chlorides). (NH4)2SO4 was identified as the lixiviant of choice and a procedure was established to investigate the influence of lixiviant concentration, temperature, pH and agitation on desorption kinetics and REE extraction levels. It was determined that the kinetics were fast and the optimum leaching conditions (for >80% total REE extraction) required pH below 5 and moderate temperatures (<50°C). INTRODUCTIONRare earth elements (REE) are at the core of numerous advanced applications due to their various uses in high strength permanent magnets, lasers, automotive catalytic converters, fiber optics/superconductors, and electronic devices (as phosphors in TVs and display screens for computers and cell phones). Because of the ongoing development of new technologies, there is an increased demand for REE in the international market, with emphasis on identifying new resources to insure an adequate supply for present and future use. World production of rare earths is dominated by China, the United States and Australia; however, in terms of resources, China dominates the world potential with reserves estimated to be over 90% of the total (Chen, 2011).The main commercially significant REE sources, as reviewed by O’Driscoll (1991) are bastnasite (carbonate) and monazite (phosphate) minerals, containing up to 70% wt. rare earth oxides (REO). In spite of being high grade, these ores are associated with elevated recovery costs due to difficulty in mining, separation and beneficiation. Moreover, aggressive conditions are required to solubilize the REE from the mineral, such as leaching with hot, concentrated acids or baking in 70% NaOH (Gupta & Krishnamurti, 2005)."

Jan 1, 2012

By D. J. MacKinnon, Kazi E. Haque

Ammonia present in a variety of mine/mill waste waters was almost completely oxidized to nitrogen by chloride mediated electro-oxidation. A closed circuit operation of preconcentration of ammonia on a suitable adsorbent (e.g. zeolite or a resin) followed by brine stripping of ammonia and electrolysis of the strip liquor seems to have sound technical, economic and environmental merits. The removal of ammonia, cyanide, cyanate or thiocyanate from a mine/mill waste water (e.g. gold mill), either individually or collectively, is also feasible by chloride mediated electro-oxidation technique. Further R&D investigations are necessary for the development of a closed circuit operation for the removal of ammonia, cyanide and thiocyanate; and also to obtain technical data for process cost estimates

Jan 1, 1996