Search Documents

By Karl J. C. Harries

"7.1. INTRODUCTIONThis chapter addresses the joint venture and examines a number of general concepts of the joint venture relationship. Chapter 8 looks at some specific concepts related to the provisions of a joint venture agreement, which are equally applicable to a shareholders’ agreement or other contractual relationship. The term “joint venture” is used because the author is a common law solicitor (a matter of convenience for which apologies are offered to civil law readers), but it should be noted that, in many aspects, the legal structure of an entity is irrelevant. It is the relationship of the parties, be they venturers or shareholders, that is important, and the areas of concern are surprisingly similar (except for terminology).The details of the joint venture relationship and agreement could fill several books. Accordingly, this chapter and the next focus on selected topics that appear to have caused problems or confusion or to be the basis for disputes. And remember that, although the following discussion is in the context of a joint venture, many of the comments apply, either directly or indirectly, to virtually any common undertaking and the agreement defining it.For interest’s sake, this chapter starts with a summary of some of the earlier types of agreements and arrangements that have evolved into the joint venture agreement of today in Canada, the philosophy of their format, and the reasons for their demise.7.2. EVOLUTION OF THE CANADIAN JOINT VENTUREThe Early DaysMuch of the opening up of Canada’s north is due to exploration for and development of mines. The early discoverers were relatively free to roam and explore at will and, if they were fortunate enough to find something, they dealt with the appropriate government to acquire exploitation rights. The early interests lay in gold or silver. Workings were small, usually worked by the owner alone or with only a couple of helpers to extract the native gold or silver. If the owner wanted to move on, he could sell his property outright and use his stake to look elsewhere.As logging and mining camps were opened, the development of better roads and railways made access easier. Entrepreneurs saw the opportunity to make money by assembling large parcels of land and working them as a single operation. In order to do this, some owners who were not ready to sell out had to be convinced to do so through more attractive offers"

Jan 1, 2003

By J. C. O'Rourke

"Gibraltar Mines Ltd. has been operating its open pit copper mine for fifteen years. In that time, over 140 million tons of waste and low-grade material has been placed on the mine waste dumps. Laboratory and in situ testing indicated that enough leachable copper was recoverable from the dumps to justify a leaching operation which would include the construction of a solvent extraction-electro winning plant. The plant, which was commissioned in October 1986, was designed to process 3000 USGPM of dilute copper solution to produce 5000 tons per year of high-quality cathode copper.This paper deals with the start-up and initial year of operation of this plant. The three areas: leaching, solvent extraction, and electrowinning are presented with emphasis on the innovations which were made to help overcome the problems unique to the Gibraltar operation.The Leaching CircuitThe mine waste dumps are leached to produce a pregnant copper solution as feed to the SX-EW plant. To achieve this the dumps are sprinkled with a mildly acidic solution which percolates through the dumps. In travelling through the dumps the solution contacts the surfaces of the liberated copper minerals and dissolves the soluble copper into the form of copper sulphate. The leaching reaction is achieved by a combination of bacterial action to oxidize the sulphides and solubilization of the copper into the acid solution.For the bacterial action to occur the dumps must be near the ideal pH of 1.9 to 2.1 and the necessary elements of the reaction must be present. Because a bacterial reaction is involved there is a lag time between the time when the conditions for bacterial growth are achieved and when the bacteria are in their active growth phase. Laboratory leaching tests with Gibraltar ore indicated that bacterial action takes two to three months to reach its maximum rate (Fig. I).The expected lag time for the planned rate of bacterial leaching prompted Gibraltar to start irrigating the dumps in late June 1986 for a plant start in early fall. The lag time proved to be longer than expected and the dumps took until November to start producing copper at the expected rate (Fig. 2)."

Jan 1, 1988

I N the introductory chapter to "Man and Metals," T. A. Rickard wrote "Five hundred thousand years ago the first footfalls of man's oncoming echoed down the corridors of time." This phrase has always appealed to me, not only for its resonance but because it seems to place in some perspective man's place in the cosmos. As we go about our daily occupations and as we meet here tonight, we must agree that we have come a long way slowly at first through the ages of change but with a quickening pace that has brought to man's know-ledge and use, within the last hundred years, more ideas, more material advantages, more opportunities and more comforts than were ever imagined or dreamed of in those long corridors of time. Looking back to the dawn of his-tory, a mere five thousand years ago, there is one aspect of the birth and growth of civilization that has particular significance for the miner and the metallurgist.

Jan 1, 1965

By Maurice A. Roche

Introduction Most of the Flin Flon ore-body, like many others in northern Canada, was covered by water. The original discovery was made where the ore-body outcropped on a strip of land jutting out into Flin Flon lake. The outcrop could be traced for a distance of 600 feet across the strip of land, but disappeared under the lake on both sides of the peninsula. Following the discovery or location of the property, in 1915, and subsequent to its examination by the H.P. Whitney interests in 1925, an extensive diamond-drilling programme was completed, which proved the existence of an ore-body at least 2,600 feet long and 900 feet deep. In plan, the central part of the ore-body at surface attains an overall width of about 450 feet; including waste horses, and gradually becoming narrower to the south. To the north, it stretches out as a much narrower tongue. The main body is a solid sulphide ore containing gold, silver, copper, and zinc. Adjacent to, and on the footwall side of, the solid sulphide ore-body, there are considerable widths of talcy disseminated copper ore, particularly in the upper 300 feet of the deposit, where the maximum widths occur. The ore-body occurs in a greenstone area, the rock being quite hard on the hanging-wall side, with the footwall schisted, talcy, and much softer. The greater part of the ore-body was overlain by 12 to 15 feet of water and from 15 to 90 feet of mud and clay, this material requiring eventual removal, regardless of the system of mining adopted. The total of mud and clay overburden was estimated at 1,000,000 tons. After considerable study, it was decided to mine the upper 300 feet of the ore-body by open-pit methods; the balance of the ore to be recovered by underground mining . The present paper gives an account of the methods adopted in both operations, and of the problems encountered.

Jan 1, 1935

By R. Le Houillier, M. Nagamori, A. J. Plumpton

"Asbestos tailings are a typical serpentine, hydrated magnesium silicate, consisting primarily of antigorite and a few per cent of unrecovered fibrous chrysotile. Serpentine has unique thermal properties in that dehydroxylating calcination at 600 to 700°C can yield an amorphous structure in which most of the magnesia is liberated from the original bond with silica and thereby rendered chemically active. The amount of activated magnesia can be quantified by selective leaching with a weak acid such as acetic acid. Many wet processes have been proposed to extract magnesium values from calcined or natural serpentine by means of various acids and their ammonium salts. However, the only commercial utilization of serpentine today is found in dry processes such as the production of fused magnesium phosphate fertilizer .The present paper reviews the physical chemistry of the dehydroxylation of serpentine and also various wet and dry processes in order to provide a general view regarding the chemical transformation of asbestos tailings.IntroductionAsbestos fibers occur as chrysotile, a serpentine polymorph. More than nine tenths of mined asbestos ores consist of massive non-fibrous serpentine, primarily the polymorph antigorite, which is discarded as tailings after fiber extraction. For many decades, Quebec has been a world leader in the production of asbestos fibers. As a result, colossal tonnages of serpentine have accumulated in the Eastern Townships'!'. Serpentine minerals are found in large deposit s throughout the world, and significant research efforts have been made, particularly in Japan and the USSR, mostly in attempts to extract magnesia or silica values therefrom.The chemical composition of serpentine (chrysotile and antigorite) may be ideally expressed as Mg3Si2Os(OH). which corresponds to 43.7% MgO and 43.3% SiO2. Natural serpentines often contain a few per cent of Ni-bearing magnetite and other impurities, and therefore the contents of MgO and Si02are both about 40% or lower.Serpentine (hydrated magnesium silicate) is virtually insoluble in weak acids. However, when dehydroxylated under controlled conditions, ' it decomposes to an amorphous state in which magnesia and silica are isolated and chemically active. The magnesia so activated is readily soluble in weak acids. This unique characteristic of calcined serpentine, first discovered in 1942,, has since attracted the attention of innumerable researchers, whence many processes have been proposed."

Jan 1, 1980

By Hu Harries

WE RECENTLY completed a study for a client, who is an applicant to export gas from the Province of Alberta, on the effects of gas export on Alberta's economy. This study was part of the client's application ?before the Conservation Board, and, no doubt, some of you are familiar with it. Submissions by other applicants in earlier hearings before the Board and before the Royal Commission on Energy, as well as claims made by parties opposing export, have also brought forward a number of other opmwns regarding possible economic effects. Ali of these studies have been on a piecemeal basis. They have dealt with particular aspects of particular applications, and only indirectly and by inference with the overall question of gas ex-port. We have prepared this paper to review the overall picture and ex-amine, as far as time permits, all sides of the question. While the paper is entitled Economic Effects of Gas Export on Alberta, we felt that the area considered should in-elude northeastern British Columbia, not only because Westcoast, the first major gas export project, is essentially a northeastern B. C. project, but because this area has historically been, from the point of view of economic, if not of political, geography, part of Alberta. In this paper, when we talk of export, we mean export from the Province or, in this case, from Alberta plus northeastern B. C. Sales to other parts of Canada have exactly the same effect on the economy of this area as l1ave sales to the United States, provided, of course, they are made on equal terms.

Jan 1, 1958

By P. C. Lighthall, D. W. Zandee, W. Shukin

"IntroductionThis chapter deals with the on land disposal and storage of fine tailing in slurry form behind dams. Other types of tailing, such as coarse dry cobbs from magnetic separation of iron ores and other dry materials, have special problems and are not addressed in this paper. The disposal of mine waste is not included, except as such materials may be of value in the construction activities related to tailing disposal.In earlier North American mining, mines were smaller and frequently disposed of their tailing by direct discharge into neighbouring streams or bodies of water. Where that was not practical or not permitted, the solids were collected in tailing ponds and only the effluent liquids were released or decanted. The dams used for these early impoundments were fragile structures and failures were common. With the advent of large, low-grade open pit mines, and increasing awareness of environmental and safety considerations, recently established mines have carefully-designed tailing disposal systems, with wellconstructed dams and attention given to protection of the environment. Older mines are being improved or at least being examined critically with a view to upgrading as necessary to meet the new standards.Modern tailing disposal systems are highly variable and unique to each mine. Tailing pond selection and design is dependent on available topography as also is the design of transport and water reclaim systems. Suitable sites that are at higher elevations than the mills or distant from them may require that the tailings be pumped. Dams, either earth or rock structures built of the most convenient and economic material, are usually a suitable mix of local borrow, mine waste and coarse tailings. The most economic structures are those built mostly of coarse tailing."

Jan 1, 1989

By S. K. Kawatra, S. J. Ripke, T. C. Eisele

It was determined by the authors that the water that remains in the filter cake after filtration in iron ore concentrators can contain several hundred times greater concentrations of calcium ions and other cations, due to surface chemical effects carrying the ions along with the water. Filter cake from two plants was analyzed. The water retained in samples of magnetite concentrate filter cake in Plant 1 contained 5088 ppm calcium and 5995 ppm magnesium, while the Plant 2 filter cake contained 231 ppm calcium and 119 ppm magnesium. These levels were dramatically elevated compared to the water that was removed from the concentrate by filtration for recycle to the plants (9 ppm calcium/15 ppm magnesium for Plant 1, and 11.9 ppm calcium/9.3 ppm magnesium in Plant 2). In addition to possible effects on agglomeration performance, the presence of these cations also affected the efficiency of filtration. In order to reduce the effects of these cations on filtration in Plant 2, carbon dioxide was injected into the slurry before it entered the filter press. This was found to increase filtration rates by up to 23.7%. Comparison of the results from the two plants shows that the concentrations of cations present in the filter cake will vary greatly from plant to plant, with correspondingly large variations in their effects on plant operations.

Jan 1, 2004

By A. E. Soregaroli, H. D. Meade

"The Keystone porphyry molybdenum deposit, located in southcentral British Columbia, is hosted by intrusive rocks of the Cretaceous Mount Lytton batholith and the early Tertiary Keystone quartz diorite stock. The molybdenite mineralization is associated with rhyolite porphyry dikes flanking a large 1300 m by 2100 m breccia complex. Recognition of the potential for the buried molybdenum porphyry system was based on quartz-molybdenite vein fragments within the hydrothermal breccias.The full extent of the molybdenum mineralization is not known. The few deep drill holes along one comer of the breccia complex defines strong metal zoning of molybdenum and associated elements of F, Mn, Zn, Pb, Au, Ag, Fe and W about the molybdenum stockwork mineralization that may be useful for guiding additional exploration. The best mineralization occurred near the base of the deepest drill hole with 0.114% Mo in rhyolite porphyry near the edge of the breccia pipe at a depth of 1350 m.The exploration history of the deposit has been complex, focussing on both porphyry-style mineralization and precious metal veins and stockworks on the periphery of the porphyry system. Exploration to date has defined an attractive porphyry molybdenum system with uneconomic grades at great depth; however, there remains significant potential to define economic mineralization elsewhere in the Keystone porphyry system and adjoining occu""ences."

Jan 1, 1995

The Cadia mine is shifting from the open pit operation to the Cadia East underground block cave. The resulting increase in milled tonnes and the decrease in fines production through shifting to block caving require an increase of over 25% in installed power. This expansion is being accomplished via the installation of up-front crushing and HPGR milling of the ore, with the SAG mill receiving a secondary crushed feed. This design, criteria and rationale for selection is presented. Over the coming years, the mine will further expand capacity. The target is to accomplish this with minimal addition of installed power or use of fresh water. This presents a challenge that epitomizes the future constraints on our resource dependent and intensive industry. The approach and proposed options to this longer-term expansion are also presented.

Jan 1, 2012

By W. Hunka

PACIFIC PETROLEUMS, Ltd. first discovered commercial quantities of gas in the Peace River area in 1952. Development of gas wells in this area is quite ex-pensive due to low penetration rates. To improve the economics, the potential of the wells in many cases had to be increased. At that time, well stimulation was still in its infancy in Canada and in this area, in particular, no treatment of any consequence had been attempted. Therefore, trial-and-error was the only means available to determine the stimulating technique that would give optimum results. Various fluid treatments were available and these were used wherever the application was warrant-ed. This paper covers acid fracture and explosive treatments as carried out on various gas-bearing horizons.

Jan 1, 1958

By Michel Dostie

Un séchoir à vis chauffé par induction électromagnétique a été développé et implanté chez Mines Niobec pour le séchage d?un concentré de niobium. Ce séchoir a permis une réduction des émissions de poussières et des gaz à effet de serre de l?usine. Il offre une grande souplesse de contrôle, une meilleure efficacité énergétique et peut être utilisé pour le séchage de granulats, de poudres ou autres substances habituellement traitées dans un four rotatif ou à l?aide de vis chauffées par un caloporteur. Le principe de fonctionnement du séchoir est simple. Trois inducteurs opérant à la fréquence du réseau électrique assurent le chauffage des parties métalliques du séchoir, dont des vis qui servent à convoyer le matériel. Le contact du matériel avec les parties métalliques chaudes permet le transfert de l?énergie requise pour le séchage. La conception de ce type de séchoir requiert un équilibre adéquat entre les besoins associés au chauffage par induction et ceux liés au transfert de chaleur par contact et au transport du matériel dans le séchoir. Cette première implantation industrielle a nécessité des efforts de développements importants et une collaboration des différents intervenants. Une revue des principes de conception, des difficultés rencontrées et des performances obtenues sera présentée.

May 1, 2007

By Maria Agostina Cinellu

Some aspects of the reactivity of the two different kinds of gold(III) oxo complexes [Au2(N,N)2(?-O)2][X]2 [N,N = 2,2'-bipyridine (bipy) (1), 6-alkyl-2,2'-bipyridine (bipyR) (2), R = Me a, CH2Me b, CHMe2 c, CMe3 d, CH2CMe3 e] and [Au2(C,N,N)2(?-O)][X]2 [HC,N,N = 6-benzyl-2,2'-bipyridine (bipyR') (3), R' = CHMeC6H5 a, CMe2C6H5 b] (X = BF4, PF6) have been studied. Treatment with water converts the unsubstituted bipyridine complex [Au2(bipy)2(?-O)2][PF6]2 (1) and the cyclometallated derivatives [Au2(C,N,N)2(?-O)][PF6]2 (3) into the water soluble monomeric hydroxo species [Au(bipy)(OH)2][PF6] (4) and [Au(C,N,N)(OH)][PF6] (5), respectively. These hydroxo species, likely the intermediates in the formation of the oxo complexes, are quantitatively reverted to the latter ones by reflux in anhydrous solvents. Both kinds of oxo complexes react with PPh3 to give OPPh3, the gold(I) complex [Au(PPh3)2][PF6] and the free bipyridine ligands. The reaction of the dioxo complexes [Au2(bipyR)2(?-O)2][PF6]2 (2a, 2b, 2c, 2e) with different alkenes gives the unprecedented alkene complexes [Au(bipyR)(?2-alkene)][PF6]. The styrene adduct [Au(bipyip)(?2- CH2=CHPh)][PF6] (7) (bipyip = 6-iso-propyl-2,2?-bipyridine c) has been characterized, inter alia, by X-ray diffraction analysis. Organic products arising from olefin oxidation are also found in the reaction mixture.

Oct 1, 2003

By N. R. Paterson, D. G. MacKay

"The geology of the Mattagami mining camp, while of particular economic significance, is unfortunately obscured by a very thick mantle of overburden. For this reason geo-physical methods have been relied upon heavily in exploring the area. Geophysical data over five important sulphide discoveries show how targets are selected for drilling and how effective geophysics has been in assisting subsequent development programs."

Jan 1, 1960

By Cheng-Ting Chiang

Information integration and exchange for the entire building life cycle is one of the most important issues in the AEC industry. Although the Building Information Model (BIM) technology is widely utilized to address them, BIM is mainly concerned within the design and construction (D&C) phases. In the operation and maintenance (O&M) phases, however, the information integration and exchange issue becomes more complicated because software applications here require not only BIM but other information outside of the AEC domain, e.g., disaster mitigation. Nowadays, most BIM-related research focuses on the D&C phases and pays less concern on the O&M phases, hence there is a research need that can help seamlessly transfer the information between the D&C and O&M phases. In this research, a software framework using ontology was designed to deal with aforementioned problems. The BIM data from the D&C phases were used as a foundation to generate new models for different software applications for the O&M phases. The ontology technique was employed to assist the model transformation process between the original BIM and the models for applications. Finally, a disaster mitigation example was chosen to validate the framework, in order to make sure that the transformation process is comprehensive and useful from domain experts? perspective.

Aug 1, 2013

By Richard Simon

This paper presents an ongoing study on the use of borehole breakouts to estimate in situ stresses at depth in a Canadian underground mine. Breakouts were identified using an acoustic televiewer (ATV) probe. Rock samples were tested in a laboratory to determine their failure curve. Breakout analyses were performed using a 2D failure criterion and a multiaxial failure criterion. Analyses were carried out using both short-term (peak) and long-term strengths (the latter considered here as being represented by the damage initiation threshold DIT). The analyses have shown that the use of the longterm strength and a multiaxial failure criterion leads to results that are more consistent with stress measurements performed in the field, in the vicinity of the mine.

Jun 1, 2012

By G. Goodall, R. Jabbar, S. Muinonen, A. Cummings

"Glencore’s Sudbury Integrated Nickel Operations in Falconbridge, Ontario, has been in operation since 1930. Many new technologies and practices, now common in the industry, have been implemented at the site and contribute significantly to the industry’s understanding. Since the last update on the Smelter operation published at the NiCo 2005 conference, the Converter Aisle has undergone significant changes in the operation of vessels. The Aisle continues to consist of 4 Peirce-Smith converters, but the Slag-Make Converter, and the Slag Cleaning Vessel have been re-tooled or re-built as Hybrid Vessels (HV), each generating matte for the two Finishing Converters and clean slag for disposal. The complicated scheduling and the overall benefits to the Smelter are reviewed here as part of the on-going tradition of industry support.INTRODUCTION The Glencore Nickel Sudbury Smelter operates a Roast Reduction Smelting (RRS) flow sheet with a specialized Converter Aisle operation that maximizes metal recovery to Bessemer matte. The main process equipment consists of a pair of Fluid Bed Roasters, a submerged-arc Electric Furnace and four Peirce-Smith converting type vessels (Figure 1). In the RRS flow sheet, concentrate is roasted with air to remove sulphur as SO2. Calcine from the Roasters is mixed with petroleum coke upon addition to the six-in-line rectangular Electric Furnace. The coke back reduces the metallic oxides, producing a matte and a discard slag.Gases from the Roasters are sent to a single pass absorption Acid Plant where the SO2 is converted to acid. Under the previous operating targets, approximately 70–75% of the sulphur in the incoming concentrate was fixed as acid with the balance going to the Electric Furnace in calcine for Bessemer matte production. Off-gases from the Electric Furnace and Converters are combined in a balloon flue, treated for particulates in electrostatic precipitators and discharged to the Smelter stack without any SO2 fixation."

Jan 1, 2017

By Michael Bauer

Increases in productivity and improvements in mining occupational safety and health are intrinsically linked. Over the past years, the German Hard Coal Mining Industry has been able to accomplish both: an increase in coal production and, at the same time, a significantly reduction of accidents. This success has been achieved by advances in technology, better organization and investment in people. Since 1990 productivity has more than doubled, while the total number of accidents has been reduced by more than 90%. Further development started initially with the mechanisation of the winning and drivage technology. Innovative technology and standardisation of the mining equipment were one reason for the increase in productivity and reduction of the accident rate. Therefore this technical development was not only one important pillar of the TOM model explicated later but also the requirement for the successful development of the other pillars. In addition to further developing this innovative technology it was possible to realise procedural and organisational improvements. As a result, the above achievement is based on implementing the three pillars of the so-called "TOM" model (technology, organization, ?Mensch? = human). To increase safety, improve performance, raise awareness and change of employees? attitude, the following technical and organizational requirements have been introduced: ??New innovative technology and procedures, standardized techniques and better equipment. ??Measures to revise or redefine the organizational structure, processes and systems of work, which were then integrated into the company policy and procedures as a company management tool. ??Personnel measures (investment in people). These include, improving motivation and behaviour, training, communication to raise and to change awareness of safety issues. Success in Occupational Health and Safety is not an automatic or self-regulating process. It needs hard work to make improvements and it must be treated as a recurring cyclic process. As a result of the above, occupational health and safety has become a natural part of daily work in the German Hard Coal Mining Industry. This could only be achieved by the unconditional "commitment" of all managers and employees to the issues, coupled with discipline and responsible action. Further improvements towards the ultimate aim of "zero" accidents are only possible by mutual involvement in implementing the ?TOM? (technology, organization and ?Mensch? human) model.

Aug 1, 2013

By E. M. Stiles

Introduction The papers that follow deal with recently completed major improvements in practices at the Sullivan operations in Kimberley. The papers have been prepared by members of the Consolidated Engineering Staff and outline the construction programme which has been in progress for the past three years, entailing an expenditure of some millions of dollars. Four major operational changes have been brought about in the mine and concentrator. They are: (1) A change in backfill procedure for filling stopes below the 3900 level. (2) A 12,000-ton,per-day sink-float plant at the concentrator. (3) A new haulage system from the mine to the concentrator. (4) A completely new crushing plant and ore storage facilities located underground. A brief outline of the background and history leading up to this overall project will be given to show how each started as an independent betterment and how they were finally co-ordinated into one major programme. The first of these, namely, the necessity for backfilling stopes below the 3900 level, was the most pressing problem. All filling to date bad been done above the 3900 level, where mining was carried on in an irregular pattern of open stoping. Stopes below the 3900 level were first opened in 1940 and are being worked on a regular pattern of panel sub-level open diamond drill stopes. The two areas are separated by a sill pillar traversing the entire length of the vein at the 3900 level elevation.

Jan 1, 1950

By J. W. Gregg, P. M. Dranchuk, D. L. Flock

"From preliminary investigations it has been observed that although evaporation losses may be estimated by comparing single values of certain physical properties of crude oils and their evaporation residues, such techniques possess little accuracy unless both the evaporation process and the variation of the property as a function of the process are completely known. The accuracy of estimation may be increased somewhat through the comparison of property mid-per-cent curves. Further increases in accuracy are possible if bottoms yield •curves rather than mid-percent curves are used. The use of both the mid-percent and bottoms yield curves however involves a prohibitive amount of effort in most cases. Examinations of distillation bottoms from Hempel type distillations carried to end points just short of the cracking point have indicated that these bottoms are not appreciably affected by the evaporation process. It was further observed that bottoms of identical API gravity, obtained from a crude oil and its evaporation residues behave as if they were pure components which were unaffected by evaporation. Based on these observations Hempel distillation bottoms of equal API gravity were obtained for a crude oil and its various evaporation residues from API gravity bottoms yield curves. The volume percent of these bottoms in the crude oil and its residues were used to calculate the evaporation losses suffered by the crude in order to yield the various residues. The results indicate that, although further refinements in technique are required, it is possible to calculate evaporation losses with an accept-able degree of accuracy through the use of this method."

Jan 1, 1960