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By A. Güney, G. Önal

"Karagedik Chromite Concentrator of the ETI Holding Co., which is located in Fethiye (south Turkey), has been producing chromite concentrate assaying 47-48 % Cr2O3 from the chromite ores containing 30-35 % Cr2O3 by using gravity separation methods since 1920. The tailings having 13-14 % Cr2O3, which had been removed from this plant, were accumulated at the stockpiles amounting about 1.2 million tons. In order to recover the ultra fine chromite particles from the Karagedik Concentrator tailings, the new process including Wet High Intensity Magnetic Separation and column flotation, was developed and the Karagedik Research Pilot Plant based on this process was commissioned in 2000. At this plant, the final concentrates assaying 46-48% Cr2O3 were produced and overall plant recoveries are about 60-65%.At the chromite concentrators using gravity separation methods, if their material size is about minus 1.0 mm, chromite particles especially pass to fine fractions according to their mineralogical structures and the ore-genesis (Önal and Güney, 1990). Generally, after crushing and grinding, the shaking tables and spirals are used at the chromite concentrators; therefore fine size chromite particles (-0.038 mm) are removed as tailings. Cr2O3 content of the -0.1 mm size fraction with 52.3% of the total amount is 19.58 % with Cr2O3 distribution of 82.6%.In order to upgrade the minus 0.1 mm size fraction of the tailings, assaying about 20% Cr2O3, Karagedik Research Pilot Plant (KRPP), which includes Wet High Intensity Magnetic Separator (WHIMS) and Column Flotation units, was installed by Istanbul Technical University (ITU), Mineral Processing Section in 2000.Feeding material of the KRPP having 5 tons per hour capacity is obtained from stockpiles amounting 1.2 million tons. After attrition scrubbing, the feed is sent to a screen with aperture of 1.0 mm. The screen overflow, assaying 5-6 % Cr2O3 is removed as tailings. Screen underflow is classified to –1.0+0.1 mm and minus 0.1 mm size fractions by using cyclone and sieve bend. –1.0+0.1 mm size fraction assaying 6-7 % Cr2O3, is sent to existing gravity separation plant. Minus 0.1 mm size fraction is firstly fed to WHIMS for pre-concentration and non-magnetic product assaying 10-11 % Cr2O3 consisting of serpentine, talc and olivine minerals are separated as tailings. Also magnetic product (25-30 % Cr2O3) obtained from WHIMS is fed to the two stages conditioners after dewatered to 30 % solid ratio."

Jan 1, 2003

By D. M. Beeson, G. D. Ortloff

Water-propelled banks of carbon dioxide recovered both high- and low-viscosity crude oil substantially in excess of that recovered by water flood in linear flow model experiments. The increase in oil recovery is explained by oil swelling and viscosity reduction. Additional oil was recovered by solution gas drive at the end of the carbon dioxide floods when the model systems were depres-sured. This study was an investigation of the use of a water-driven carbon dioxide bank to recover crude oil. Techniques involving the injection of carbon dioxide have aroused con-siderable interest in recent years among methods considered for increasing oil recoveries. A number of investigators have studied the process in the laboratory1-' and in the field.7,5 Laboratory studies referenced indicate that carbon dioxide in conjunction with water flooding recovers more oil than does water flooding alone. These re- ports diverge widely, however, in stating magnitude of improvement. We believed that a water-driven carbon dioxide bank would increase recovery of crude oils by two mechanisms: viscosity reduction and oil swelling. Due to reduction in the oil viscosity caused by solution of carbon dioxide, displacement efficiency should be improved. In addition, the residual oil should be highly swollen by the carbon dioxide held in solution. Thus, the final residual oil saturation, in terms of stock-tank oil, would be lower than in the absence of carbon dioxide. To test this hypothesis, experi-

By Helmer Hedstrom

GRAVITY surveying with the torsion balance or the pendulum for ore prospecting purposes has generally not been considered practical or even possible. It is the intention of this paper to show that a fast and sensi-tive gravimeter can be very useful in ore prospecting, as an auxiliary to the electrical and magnetic instruments. A number of gravimeters have been constructed and put in practical use in the last seven or eight years; for instance, by Ising, Lejay-Holweck, Haalck, Hartley, Thyssen, Noergaard, the Humble Oil and Refining Co. and the Gulf Production Co. Their main application, apart from their use for geodetic surveys, has been for structure mapping in oil prospecting. There is no record that any of them have been used for ore prospecting. About the middle of 1934 the Boliden Mining Co., in Sweden, began experiments in constructing a static gravity meter sensitive enough for ore prospecting. Calculations and considerations that will be discussed later in this paper showed that this would necessitate an accuracy in the measurements of 0.1 milligal-roughly, one ten-millionth part of the total force of gravity. The first successful practical field tests of the instrument were made in January 1936. About the middle of 1937 the Boliden gravimeter was perfected. Ore prospecting with this instru-ment is now regular practice in Sweden, especially for the testing of indications given by geoelectric and magnetic methods.

Jan 1, 1938

R. B. BRinsmade, Ixmiquilpan, Hgo., Mexico (written discussion").—how far ahead of the United States are the self-governing British colonies in their application of economic democracy is well illustrated by Mr. Godson's paper. To prove this, I need quote only two of his assertions, the italics being mine: "lt is a stern fundamental principle that a11 natural resources are the inalienable property of the crown.'' "The right to a claim should only exist as long as it is worked or taxed to insure work. Once depart from that sound maxim, there results improper control of the natural resources of the country, which primarily belong to the people." These assertions formed the basis of my criticism1 of Dr. Raymond's paper in 1913, and they should be inscribed in letters of gold above the entrance to the office of every county recorder in the United States. I venture to assert that the existing United States mineral land laws are essentially unfair to the nation and a hindrance to the legitimate miner, because they fail to embody the above quoted principlca; and this applies both to state laws east of the Mississippi and to federal laws in the West. That these laws favor the forestaller and the monopolist, defraud the government of its fair share of the profits of mineral production, and tend to industrial feudalism must be evident to any competent unbiassed observer. The fact that no serious political movement arose to change them, until the conservation agitation of the last decade, may be largely explained by two salient conditions. First, as stated by President Winchell, "for a long time there was such a vast surplus, or excessive amount of unwanted, undesirable land in the West that the land offices did not scrutinize the claim sought to be located;" second, that the millions of individual farm owners throughout the country could easily be aroused, by the special pleaders hired by the great land speculators and monopolists, to use their vast political power for the suppression of any statesmen striving to incorporate in our semi-feudal land laws any such principles as those quoted from Mr. Godson. While agreeing with Mr. Godson that a freehold or fee-simple title, if coupled with obligatory continuous work, may have the same practical effect as a lease, it seems to be the experience of the most active and

Jan 1, 1920

For the last 4 years political leaders have found a new subject on which they can safely generalize wihout creating opposition. That sub- ject is commodity prices. Since the four-fold increase in OPEC crude oil prices, public atten- tion has focussed as never before on the subject of commodity prices. To advocate stabilizing com- modity prices is akin to supporting motherhood or peace or better schooling. Everyone gives lip service to the concept that stable commodity prices are desirable. It is easier to state the principle than to achieve it. Prices that are stable in terms of one currency may be clearly unstable in terms of a different currency. This has become a troublesome matter since 1971, when the world's leading trading currencies were set free to float in relation to each other. To illustrate: consider copper prices in the interval between the end of 1974 and the end of 1977. During those 3 years, the copper price in pounds sterling on the London Metal Exchange rose by 25 per cent. During that period, however, in terms of the USA dollar equivalent, the price was unchanged. And during that period, in terms of the German mark equivalent the price shrank by 13 per cent while the Japanese yen equivalent f.11 1k

Jan 1, 1978

By Ham G. I, Just G. D

The model considers a range of design parameters and operating condit- ions and evaluates the significance of these in the ultimate design of a mine. It also considers organizational features associated with the mining method and examines the inter-dependence between operations. An important characteristic of the model is the use of both stochastic and deterministic methods to study the behaviour of the complete mining system. The simulator selects the appropriate unit operation, computes and records its time, performs it and then calculates the production and cost data. Output is in the form of shift, day, week or period repor-ts. These reports will indicate problem areas such as restrictions in the production network for a given set of conditions. The likely effects of alternative means of solving these problems can be evaluated by changing the original input. Such information could be used by the mine management to select an

Jan 1, 1974

By C. W. Kempton

IF New England were located in some distant and almost inaccessible region, there is no doubt that its mineral resources would have been ere this well developed and generally acknowledged, but laboring under the disadvantage of nearness, it has been neglected. Its surface, moreover, is not cut up by mountains and canons, and the remnants of many of the old ridges are extensively covered by glacial drift. Having for the past ten months been engaged in the development of a. mineral district in Southeastern Maine, I would take this opportunity to lay before the Institute sketches of results, and try to give some idea of the formations as found. The Sullivan Mining District extends from the town of Franklin, through Hancock, Sullivan, and Gouldsborough, from northwest to southeast, about sixteen miles. A general idea of this locality may be gathered from the map accompanying. (Fig. 1).

Jan 1, 1879

By M. Stefanakis

Respect for the people is one of the main values of S&B. Such respect needs to be manifested by actions ensuring the bodily and spiritual integrity of personnel in pursuing their work. The ultimate target is to achieve zero accidents by developing the culture and infrastructure required to support it. Within this framework, the following proactive safety practices were introduced in 2004 and are implemented at S&B Greek sites: (a.) Management Safety Visits (MSVs) of shop floor operations to address safety attributes of work guidelines, (b.) Monitoring compliance with critical work guidelines, using a ?safety barometer? tool. The proactive nature of both above systems, facilitates communication with employees on safety behaviors and their adoption in our facilities at Milos and Fokis, has been successful. Above all, these practices corroborate the management?s concern for the people and its commitment to continuously improve the working environment.

Jan 1, 2007

By T. Cuscino, D. D. Lane, C. Cowherd, T. E. Baxter

Three types of commercially-available dust suppressants, commonly used in the surface mining industry to control fugitive particulate emissions from unpaved roads, were tested in the laboratory for cohesive strength and resistance to reduced effectiveness by large water addi¬tions. Results indicate that each product tested varies in cohesive strength with a range of 34-300 kPa (5-44 psi). Total cohesive strength depends on the aggregate moisture content and the means by which the sample is dried. Results show that laboratory testing can be used as a decision¬making tool concerning the type of dust suppressant for a particular mining operation. Also, the road surface aggre¬gate moisture content u critical to successful dust suppres¬sant performance. Large water additions to the aggregate road surface after initial suppressant application can pro¬duce nondesirable results. A modified wet sieving analysis is presented to test the effect of water addition.

Jan 1, 1984

By Scott G. Britton

In the real world of coal mining, the bottom line for almost every support project decision is economic (i.e., what is it going to cost?). Up to this point, I have discussed the methods to improve the performance of typical support projects by better installation, materials, and techniques, thus lowering the impact of the bottom line cost. In this chapter, 1 shall explore what costs are relevant in mining construction, and how these costs are developed. The chapter centers around two major discussions: (I) developing cost accounting techniques, and (2) cost-estimating procedures for support construction. Each focuses on the fundamentals of practical cost considerations necessary for decisions on construction projects underground. Since cost accounting, economics, and investment planning are all subjects which warrant complete discussions on their own, this chapter will focus on distilling the important concepts required by a planning engineer into an easily understandable presentation.

Jan 1, 1983

By Waters A. G, Nightingale R. J

The quartzite added at the blast furnace for the purpose of adjusting the chemistry of the burden inputs is shown to have a disproportionate impact on both the level and the variability of the hot metal silicon (HMSi). This conclusion is supported not only by direct correlation involving data from five blast furnaces, but also by mass balances. In one case the R2 correlation coefficient was 0.96 and the mass balance was accurate to within five per cent for a wide range of quartzite additions. The results indicate that as much as 43 per cent of the silicon in the added quartzite reports directly to the hot metal. Indeed, silicon from quartzite was found to be much more likely to report to the hot metal compared to silicon from regular sources (eg coke and sinter), reflecting differences in the activity of the silicon source.

Jan 1, 1994

By O. C. Blade

This report on the properties of motor fuels sold through service stations In the United States was made In accordance with a cooperative agreement between the American Petroleum Institute and the Bureau of Mines of the United States Department of the Interior. By agreement with the American Petroleum Institute, identification of the items Is confidential. 1t presents analytical data for 4, 802 samples, representing the products of 117 companies. The samples were collected during December 1954 and January and February 1955. As in previous surveys, the gasolines covered 6y this survey Include those from both large and small suppliers. The data were obtained by laboratories of various refiners, motor manufacturers, and chemical companies and submitted to the Bureau of Mines for compilation, A list of the National Motor-Gasoline Survey reports published during the past 10 years is given on page 5.

Jan 1, 1955

By N. A. Barcza

This paper describes the development of large-scale thermal-plasma systems, which was motivated, in general, by the potential cost savings that could be achieved by their use as a replacement for the more conventional methods used in the generation of thermal energy. The anticipated cost savings arise not only from the use of plasma-generating devices but from the manner in which they have been interfaced with a furnace to process particular materials, mostly as fines. Thermal-plasma systems fall into two categories: non-transferred-arc and transferred-arc devices. In general, transferred-arc devices have been interfaced with open-bath furnaces in which melting or smelting processes carried out, while non-transferred-arc devices have normally been applied to shaft furnaces. Water-cooled transferred-arc devices are somewhat limited in power (about 5 MW) because of the relatively voltages (300 to 500 V) that can be attained in open-bath furnaces, where very long arcs are undesirable, and because only relatively low levels of current can be carried. Graphite electrodes can overcome the restriction current, and power levels of 30 to 50 MW seem feasible, even with one electrode, if direct current is used. Multiple water-cooled devices are capable of attaining similar power levels, but the capital costs are much higher. Costs due to electrode wear are lower for water-cooled systems, but expensive gases are needed for transferred-arc devices. Mintek conducted extensive pilot-plant work in which water-cooled devices were used initially but graphite electrodes were used subsequently to produce ferochromium from fines. Transferred-arc open-bath configurations were used. This work led to a decision by Middelburg Steel & Alloys (MS&A) to install a 16 MVA furnace of semindustrial scale to produce ferochromium aloys based on the ASEA d.c. arc furnace developed for the Elred process. Non-transferred-arc devices have atained reasonable scale-up to the 6 to8 MW power level, and high-voltage operation, which is inherent in such devices, has enabled lower currents to be used. Nevertheless, multiple systems are still necessary to accommodate large-scale applications, and this can be costly from a capital point of view. The cooling requirements are large, and can represent a considerable loss of electric energy. Shaft furnaces equipped with non-transferred-arc devices are suitable for the processing of materials that have volatile species, e.g. silica or manganese, or where the shaft is used to prereduce oxides that are amenable to gas-solid reactions. It is probably in the treatment of light and refractory metals that plasma technology will achieve its greatest development in the years to come. The energy requirements for the production of these metals are high, and very low oxygen potentials are necessary. These are factors that favour thermal plasma. Much developmental work is still needed in this interesting field. It should be remembered that electrically generated thermal energy is a unique temperature source that, in many instances, cannot be replaced technically or economically by the combustion of a fuel.

Jan 1, 1986

By S. D. Warriner

ONE of the most, if not the most, difficult of the problems associated with the mining and distri-bution of anthracite is to get clearly into the minds of the consumers and of the editorial and reporto-rial writers in the public press the relationship between the cost of production, the price at the mine and the price that the consumer pays for his coal, delivered in the cellar. One sees in his morning paper a statement to the .effect that out of the $12 or $13 per ton that his dealer charges him, the miner gets only $2 or even less, and he asks himself or the paper asks for him, "Who gets the difference?" Not infrequently the amount that the miner gets is given for run-of-mine bituminous coal while the price quoted is that of prepared anthra-cite, egg, stove, or chestnut, as the case may be, delivered to the bin of the consumer; and the difference stands out with all the more prominence; and it sticks in his memory with a persistency which no manner of explanation is able to efface. A recently published official report for the year. 1921 of one of the State Bureaus stated the total production of anthracite in net tons of 2000 lb., and included not only the output recovered by washeries from old culm banks and by dredges from creek and river channels, but also the colliery consumption;, i.e., the coal used by the companies in the operation of the collieries. This resulted in a total production of 90,509,075 net tons for which the labor cost was stated at $283,961,300, or $3.13 per net ton, equivalent to $3.50 per gross ton. This figure of $3.50 was immediately seized upon as representing the labor cost per gross ton of fresh-mined commercial coal. It is almost a hopeless task to try to correct such errors of statement in the first place, and, in the second place, to correct the misapprehen-sions that arise from them. As a matter of fact, the report was misleading in regard to the labor cost of the entire production shipped, as the coal used for colliery consumption should be deducted. Correctly stated, the report should have shown, calculated in terms of gross tons of 2240 lb., the legal weight in Pennsylvania, as follows: Gross production 80,607,359 tons Less colliery fuel 8,757,137 tons Commercial production 71,850,222 tons Total labor bill $283,961,300.00 Labor cost per ton...: 8 3.952 The foregoing figures" of tonnage are obtained from the State Department of Mines. Even these include the quantity recovered from calm, banks by washeries, and consequently the $3.95 arrived at as the average labor cost is somewhat less than that actually involved in the mining of fresh-mined coal. Unfortunately, the figures of washery production and the cost of producing it are not available.

Jan 7, 1922

By J. R. Vilelia

IN accordance with the custom of this society, we are gathered here, as we have every year since 1924, to honor the memory of the eminent American metallurgist and teacher, Professor Henry Marion Howe. Unlike many of the distinguished metallurgists who have preceded me as a Howe lecturer, I cannot bring to you reminiscences of his personality, for it was not my privilege to be associated with Professor Howe, or to be directly one of his students. Yet, Professor Howe and Professor Albert Sauveur, through the medium of their books, were my first teachers of metallography, as they have been of almost all American metallurgists of my generation. As a teacher, and for many years the acknowledged leader of American metallurgists, he exercised a profound influence in the growth of our science and was held in honor by the men of science of his time. I can speak no words of technical appreciation that will add luster to his fame, for by his prophetic vision, his teachings, and his researches he stands among the immortals in the memory of all metallurgists. In 1926, the third Howe Memorial Lecture was presented by Professor William Campbell' of Columbia University, who entitled it "Twenty-Five Years of Metallography." He took as a starting date for his chronology the turn of the century, which coincided with his arrival from England to work in association with Howe at the Columbia School of Mines. In that informative lecture Professor Campbell enumerated the important advances in metallography achieved during the first quarter of the century, and, it now appears, may have established the custom of reviewing such progress every twenty-five years. The scope of Professor Campbell's lecture was as broad as his metallurgical knowledge, for it embraced a wide portion of the field of metallography, both ferrous and nonferrous. Twenty-five years later, the Howe Memorial Lecture Committee saw fit to assign to me the honor of writing a lecture that would commemorate the work of Henry Marion Howe and would at the same time constitute the 25th anniversary of the lecture by Professor Campbell. The Committee suggested that this lecture might properly be called "Twenty-Five More Years of Metallography," a suggestion that I have adopted. I must confess, however, that I have not followed the precedent established by Campbell and have narrowed the scope of this lecture to an appraisal of those achievements which in my opinion have contributed most to the progress of microscopical metallography during the past twenty-five years. Progress in Metallography The metallographic methods most widely used today, with the exception of the electron microscope, were firmly established more than twenty-five years ago. In general, our specimens were prepared for microscopic examination in those days in much the same manner as they are today. It is true that new details of technique have been introduced from time to time, and that superior equipment is available today, but on the whole, these improvements have been in the nature of refinements, often a matter of personal preference, and none can be considered essential to the attainment of the ultimate goal of the art and science of metallography, which is to reveal the structure of metallic specimens with unequivocal clarity so that they may be interpreted correctly. Mechanical metallographic polishing, which was the only method available in 1926, is still universally practiced and still consists of abrading the metallic specimen with a series of abrasives of increasing fineness until a specular surface is attained. We have now the alternative method of electropolishing, but it is not widely used because, except in a few special cases, its results are inferior to those of competent mechanical polishing. Likewise, most of the etching reagents preferred today were in common use more than twenty-five years ago and were applied in the same manner as they are today. Valuable improvements have been made in the optical and mechanical performance of metallurgical microscopes, but there was no dearth in those days of excellent instruments equipped with achromatic and apochromatic objectives capable of yielding micrographs comparable in quality with the best that we can make today. In fact, it would be a difficult task for any metallographer today to make optical micrographs at magnifications in excess of 3000 diameters that would surpass those made by Lucas more than twenty-five years ago. One of these is shown in Fig. 1. Yet, it is unquestionable that on the whole, the micrographs appearing in the metallurgical literature today are vastly superior to those

Jan 1, 1952

By G. K. Manning, M. C. Udy, L. W. Eastwood

Those who have examined beryllium and beryllium-rich alloys under the microscope have noted the results of the difficulties encountered when preparing these materials for examination. Hard constituents are readily chipped and pulled out of the matrix, and the soft ones are easily gouged out or embedded with abrasive or other material. The matrix is easily deformed, which makes it very difficult to remove the effects of scratches. Furthermore, the matrix and some of the constituents are also readily pitted during etching, which makes the structure difficult to develop. The metallographic techniques designed to avoid these difficulties are neither radically new nor necessarily the best possible procedures. They were developed at Battelle to fill immediate requirements as part of a study of the preparation and pouring of beryllium melts as described in a separate paper. A part of the research program on the causes of gas unsoundness in beryllium castings entailed a study of the effects of such gases or gas formers as oxygen or oxides, nitrogen or nitrides, and carbon or carbides. These gases or gas formers, if dissolved in the melt, might be an important factor in the study of unsoundness caused by gas evolution in beryllium. Because it was necessary to be able to distinguish these gases or gas formers, if present as alloy constituents, from metallic phases also present as alloy constituents, a series of alloys was prepared with additions of the various possible metallic and non-metallic constituent formers. It should be emphasized that the constituents referred to as gases or gas formers are important in the study of gases in beryllium only if they form a part of the alloy, that is, if they dissolve in the liquid or solid metal. During the first part of the development of metallographic techniques, the Massachusetts Institute of Technology, unpublished report (TC 3315, Nov., 1945) by Paul Gordon, describing various microconstituents in beryllium, was quite useful. Of particular interest in this report is the confirmation of one of the conclusions drawn from the present investigation, that is, that a distinct oxide phase apparently does not occur in beryllium. The Preparation of Metallographic Specimens GRINDING PROCEDURE The original specimen is either sawed or cut on an abrasive wheel to a convenient size. For best results, the surface to be polished should not be more than about 1/4 in. square, and it is convenient to mount the specimens in bakelite to facilitate handling. Two alternative grinding procedures have been developed. As one alternative, specimens are ground successively on 120-, 240-, and 400-grit, wet-or-dry metallographic discs. The abrasive discs are revolved at 1750 rpm on a conventional pedestal grinder. The coarsest disc (120 grit) is used either wet or dry, and in most instances, it can be eliminated from the procedure. Grinding on the two finer discs (240 and 400 grit) is accompanied by the application of kerosene. The technique consists of holding an oil can, containing kerosene, in one hand and the mounted specimen in the other hand. While the grinding is being done, several drops of kerosene are applied every few seconds close to the center of the disc. Carbon tetrachloride serves at least as well as kerosene as a lubricant; perhaps it is slightly better, but it volatilizes so readily that an additional health hazard is involved. Light oils and water are not satisfactory for the finer grinding operations. The second procedure is perhaps slightly slower than the first and requires a more careful technique, but it eliminates the use of kerosene. The specimen is first ground wet on a 240-grit disc, followed by dry grinding on a 400-grit disc. Finer grinding does not appear to be necessary with either of the two alternative procedures. The pressures used throughout either grinding operation must be extremely light, that is, barely sufficient to hold the specimen in contact with the disc; otherwise, flow and chipping are almost certain to occur. In both procedures, it is essential that the discs be sharp and that they be discarded as they show evidence of becoming dull or loaded. In general, not more than four or five specimens can be ground on a disc before the disc becomes dull enough to warrant discarding it.

Jan 1, 1950

By John Freer

The time 06h30 in midwinter is a little early to set out on an excursion from Johannesburg. Yet this was the hour that members, many accompanied by their wives, started to assemble in the parking lot adjacent to the squash courts at the Wanderers Club, Illovo, for a visit to Premier Diamond Mine at Cullinan. All fifty were checked in and aboard the coach by 07hOO. Coffee and sandwiches, served en route by Doris Gardner and Pam Binstead, were most welcome. IMM awards Given below are details of the trust funds, etc., to which applications are invited for grants, etc., payable in 1985. Application forms, which must be returned to the Secretary before 15th March, 1985, are available on request. Applicants should note that, in general, preference will be given to members of the Institution.

Jan 1, 1984

Factors influencing Cost, systems available for transporting minerals, particularly on land, and methods used for comparing costs are reviewed. A case study presents comparative costs graphically for coal haulage, assumed in Queensland, by 31-6" gauge rail, belt conveyor, 120 ton road train, slurry pipeline, and transmission of electrical energy by transmission line. The effect on comparative results of alternative methods of including initial capital and capital replacement costs is considered and approximate break-even points between systems, bearing in mind the assumptions taken, are discussed.

Jan 1, 1973

By Richard C. Williams, Herman Pieterse, Ken Thomas, K. S. Fraser, Ron H. Colquhoun

"The Banick Goldstrike Mines Inc. (Goldstrike) operation is located in Eureka County in north-central Nevada on the Carlin geological trend. Gold in the sulphide mill feed, occurs primarily as submicroscopic inclusions or possibly solid solution in a pyrite and marcasite matrix. Sulphide mill feed is pretreated in a pressure oxidation plant allowing gold recoveries of 90 per cent and greater to be achieved. Anticipated 1994 gold production for the sulphide gold facility is approximately 1,500,000 ounces.In January 1989 American Banick Resources Corporation (Banick) announced the US$365 million Betze Development Plan for the Goldstrike property. The Betze plan was based on a three (3) staged expansion of the original 4,500 STPD oxide gold plant. This expansion would involve addition of ore and gold processing capacity and the total conversion of all ore handling facilities to treating Betze sulphide ores.Phase 1 of the Betze Development Plan involved the construction of a pressure oxidation circuit, including a single autoclave and supporting ancillary services. The pressure oxidation circuit was commissioned in February 1990. Currently a throughput of 2,000 STPD is being achieved.Phase II of the Betze Development Plan, commissioned throughout April and May 1992, included the expansion of grinding, leaching, and gold recovery facilities enabling the treatment of combined oxide, and sulphide ore. Pressure oxidation capacity was increased by the addition of two (2) autoclave circuits each treating 2,600 STPD of sulphide ore and other required ancillary services. By June 1992, the Phase II gold facility had achieved a combined throughput of 15,000 STPD of oxide and sulphide ore.Phase Ill, the final stage of the Betze Development Plan, was successfully commissioned in February and March 1993. This final stage of development increased the design throughput of the pressure oxidation plant to 15,000 STPD by the addition of three (3) autoclave circuits with combined capacity of 7,800 STPD."

Jan 1, 1994

By Lawrence Cheng-Kwang Hu

"Since the only available delay detonator in Taiwan is electric delay detonator, which can beaccidentally initiated by fire, i impact force, friction, static electric, lighting, radiotransmitter, and stray current etc., that always represent fatal threatens to the blasting crew.Fire, impact, friction can be Prevented by handling carefully; lighting also can be detectedwith proper instruments. But when a blaster find an unknown extraneous current in his welllaid down blasting cable; what a horror scence will be expected especially the electricdetonators have been connected already."

Jan 1, 1993