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By A. J. Nicol

Field experience in uranium has shown it is most economical to ram through a drilling program to obtain maximum footage per drill hour. Drift surveys can then determine the course of the holes. Using this method is generally cheaper than paying the additional cost involved in using the drilling technique and equipment necessary to maintain straight holes. Factors Affecting Direction of Bit Travel: In all rotary-drilled holes there is an interplay of forces or conditions affecting the direction of bit travel. Rarely is a straight vertical hole obtained. One of the major factors is weight on a drill string. In looking at a joint of drill stem it is hard to imagine its being quite flexible, but flexing of the steel increases when many joints are made up together, and even a slight weight added to the upper portion causes a buckling or spiraling effect in the hole. The result is that the bit deviates from the vertical.

Jan 1, 1959

By Richard S. Kunter

Artech Recovery Systems, Inc has developed a low pressure and temperature? leach process called the "Cashman Process" to extract metals from arsenical flue dusts and residues and fix the arsenic in an environmentally stable form as ferric arsenate (scorodite). The process was pilot tested at Hazen Research in an integrated plant including continuous recycle from August 1989 to October 1989 during which several tons of flue dust were processed. Based on this pilot program, the process was deemed technically feasible and produced commercially salable products. Residues from this pilot program were subjected to a long-term stability test jointly designed by PTI environmental services and the USEPA. The process, its versatility, and the nature of the products is discussed in some detail.

Jan 1, 1992

By D Connelly

Silver and gold bearing ore from the Troy Resources NL Casposo Gold-Silver Project, located within the San Juan Province of Argentina contains a complex mix of gold, silver, electrum and silver sulphides in the ore. Casposo is a typical low sulphidation epithermal style gold–silver deposit where mineralisation is hosted within rhyolite – andesite flows and breccias. Veins are typically banded quartz–chalcedony colloform - crustiform banded with quartz - carbonate infill. Mineralisation is associated with an assemblage consisting of quartz, chalcedony, adularia, calcite, illite, sericite and trace sulphides. Gold and silver occur as electrum, native silver, sulfosalts and silver sulphides. This paper presents a case study that describes the process selection, development and engineering of a tailored process plant for the recovery of gold and silver from this ore.The original feasibility study, modelling, metallurgical testwork and engineering studies are outlined. The final flowsheet was based on minimising capital cost, operability, recovery and minimising technical risk.The process flowsheet uses the traditional Merrill Crowe route because of the high silver to gold ratio in the feed and achieves maximum gold and silver recovery while providing a common facility for future ore body treatment.

Aug 8, 2011

By K. Dewar

The catalytic converter industry is composed largely of global multinational manufacturers who supply to vehicle manufacturers (original equipment manufacturers ? OEMs) from facilities strategically located internationally, including plants in South Africa. The South African catalytic converter production facilities were established at the request of the OEMs and commenced manufacture in the early 1990s. This near 100 per cent export focused industry exists in South Africa because of the incentives offered by the Motor Industry Development Programme (MIDP), which ultimately provide the OEM with import duty rebates. The South African catalytic converter industry is a complex vertically-integrated supply chain with a local content in excess of 85 per cent, substantially more than any other exported automotive component. The industry remains one of the very few downstream manufacturing industries where South Africa has a significant global footprint. This is even more important when it is considered that this industry is the key end-user for two of South Africa?s most important mineral resources, namely platinum group metals (PGMs) and chromium, and is in an industry which will see massive global growth as the developing nations of the BRICs grow their auto industries. In over 15 years of existence in South Africa, the catalytic converter industry has achieved remarkable growth, averaging compound growth in the region of 14 per cent per annum. The industry is the highest contributor to automotive component export revenue. South Africa holds >8 per cent% of global PGM reserves. During 2011, South Africa supplied 59 per cent, 29 per cent, and 72 per cent of the global demand for platinum, palladium, and rhodium respectively, as well as over 50 per cent of the global chromium demand. Global autocatalyst production remains the largest consumer of PGMs, and South Africa alone beneficiated 15 per cent of locally mined PGMs in the production of catalytic converters ? all is converted from PGM sponge (powdered metal) into PGM solutions for coating onto catalysts. Beneficiation of PGMs also takes place via the production of jewellery and electronic goods; but compared to catalytic converters, this volume is negligible. The industry is also the largest consumer of locally produced stainless steel (>50 000 t/a), exceeding 38 per cent of local consumption. The industry is a substantial generator of highly skilled employment, with over 5 000 direct jobs (excluding OEMs and stainless steel manufacture) and an estimated more than 30 000 indirect jobs resulting from upstream and side-stream suppliers. The industry places a high focus on skills transfer and development, with all companies providing high-tech training and education both locally and overseas. The industry has invested in excess of R5 billion in plant, equipment, people development, and process development over the last 15 years to support transfer of production and new technologies to South Africa. This has resulted in significant skills development in the support industries as well as within the catalytic converter industry. The current projections for local PGM beneficiation via catalytic converters reflect a downward trend as a result of production being moved to other global locations due to uncertainty around changes to government incentive programmes. The industry is currently capacitated to support 23.7 million units per annum. During 2011 it utilized about 70 per cent of this capacity, but forecast projections suggest that this will be at 46 per cent of this level by 2016. At full capacity the industry would represent 19 per cent of global autocatalyst production compared with the current 13 per cent in 2011. The industry believes that there is potential to make South Africa the preferred location for catalytic converters worldwide, given suitable support from the mines and Government.

Jan 1, 2012

By Tomás Vargas

The catalytic role of Thiobacillus ferrooxidans in the dissolution of chalcopyrite was studied by leaching pure massive samples of this sulfide with a pure strain of Thiobacillus ferrooxidans (ATCC 19859). Monitoring of the bacterial activity showed that an important fraction of the total bacteria generated during leaching remained attached to the chalcopyrite surface. Bacteria grown in the system, which were the offspring of bacteria adhered to chalcopyrite, was well explained as the result of the utilization of ferrous ion and sulfur as energy sources. The potential for indirect and direct action was fully utilized by the existing bacteria and the leaching process was controlled by the kinetics of chalcopyrite dissolution.

Jan 1, 1990

By Pieter-Jan Kleiterp

Caterpillar has been involved in highwall mining since the purchase of Bucyrus in 2011. The Cat® HW300 is a continuation of the Superior Highwall Miner that was first sold in the USA in 1994. Currently, there are more than 80 machines supplied worldwide, and Caterpillar envisions increasing the population steadily in the coming years. The Cat highwall miner product group, based in Beckley, WV, has been involved in the sales of all miners to date. With the dealer model that Caterpillar is using, more people, dealers in particular, need to be trained on the application of highwall mining. A site investigation is a highwall specialist?s work, and Caterpillar assists dealers and customers in determining the technical feasibility of highwall mining on mine sites. With the ever-increasing amount of requests, it proved to be important that people without highwall mining expertise, yet who are familiar with mining, could perform a very quick analysis of a potential highwall mining site to determine at an early stage if it is worthwhile to invest the time and money of all parties?customer, dealer, and Caterpillar?in further follow-up. Therefore, Caterpillar would like to introduce the Cat HW300 QuickScan tool.

Jan 1, 2014

By R. Tunold, Y. J. Zhang

"The cathodic kinetics of aluminum deposition from aluminum chloridealkali chloride melts was studied by use of electro-cnemical transient techniques at 700 °C. Aluminum deposited as an insoluble product on a glassy carbon electrode and as a partly soluble product on a tungsten electrode. The deposition was found to be a simple diffusion controlled process involving the exchange of three electrons. The diffusion coefficient of aluminum chloride was calculated - 4.sx10-s cm2 ·S-I in AlCl3 -NaCl-LiCl melts and 2.6x10-s cm2 ·S-' in AlCl3 -NaCl-KCl melts. For AlCl3 -NaCl-CsCl system the diffusion coefficient exhibited some uncertainty due to nucleation. The determined rate constant of aluminum deposition reaction was on the order of 10-' -10-2 cm'S:' Constant potential electrolysis was carried out. TiB2 was well wetted by aluminum. The species of melts penetrated into graphite and glassy carbon but not into tungsten. The diffusion coefficient of species in glassy carbon was evaluated.IntroductionAluminum chloride electrolysis is attractive for its power saving of 30%. Different process to circumvent the conventional chlorization to obtain aluminum chloride economically, such as directly chlorizating mixture of Al~03 and C in a cell with A-shaped laminated bipolar electrodes by rising chlorine (1), or by use of a composite anode (2), will promote the electrolysis technology to be realized industrially. With the appearance of the Alcoa process periodically there are studies on the kinetics of aluminum deposition. Some discrepancies seem to exist on the mechanism of aluminum deposition. Borne studies (3,4,5) showed that the deposition of aluminum was hindered by diffusion process in the melts. M.Gabco et a1. (6) claimed a preceding dissociation of a complex being the rate controlled step. This paper presents our results on the mechanism of aluminum deposition from the study by use of transient techniques and some results from constant potential electrolysis."

Jan 1, 1988

By WM. G. Heeley

This paper will describe the experience gained and explain the deductions made from the phenomenon of the great squeeze which occurred at Brule Mines. The first indication of the commencement of the squeeze was the breaking of posts on the high-side rib of the slope. At first we thought this was due to a lateral pressure only, and we renewed the broken posts with new ones, the result being that the new posts also were soon broken. A noticeable bending and breaking of the collars occurred, with a corresponding reduction in the height of the haulage slope. These symptoms were also evident on the counter above the slope, indicating that the trouble was of an exceptional nature. In the meantime, we had concentrated a large force of repair men, renewing broken timbers and brushing the roof and floor, but in spite of all our efforts we could not overtake the damage being done. Our next problem was to find the cause of this trouble. We were in a new basin of coal (No. 2) which had only been opened a few months, as we had worked the previous four years in another basin (No. 3) where no such trouble as this had ever been encountered. Naturally our first thought concerned the adequacy of the size of the pillars. We had worked in the No. 3 south basin for the previous four years. without any such experience, with 60-feet pillars between slope and counters; whereas we had established 100-foot pillars in the No. 2 south basin between the slopes and counters with an 80-foot pillar between counter and first line of cross-cuts, and 100-foot pillars between the breasts.

Jan 1, 1924

The phenomena of nature cannot present themselves to any thinking wild without claiming from it some solution. The earth, as it has often been observed, is laid out like a well ordered cabinet, presenting to us, in measure, some means of judging how the laws of nature and the essential properties of matter have worked out all we see before us. "That there have been depositions of strata gradually laid down aud stocked with the remains of the living objects, vegetable and animal, that flourished when they were being imposed, is an universally acknowledged fact. It speaks of a constantly maintained series of operations whereby the globe has been brought to its present condition, and which are ever advancing it to stages that are still before it. That immeasurable ages have been consumed in effecting these developments is also conceded. We witness the very graduated rate of the existing advances and can see that the past action must have been conducted in the same slow deliberate manner. There are many questions, however, upon which inquirers are not agreed, hence they are still within the domains of fair discussion.What has led to those great climatic changes whereby the same portions of the earth have had at various times climates that were glacial, temperate, and tropical? What causes the constant contortions and dislocations of strata and the upheaval and depression of land levels, and that there is a tendency to alternation in the parallel areas undergoing opposite kinds of movement as if the sinking of one area balanced the rIsing of another? What is the reason that the centres of volcanic action are continually shifting, and that the line of greatest activity is always upon the rising areas? That portions of the earth have been subjected to intense alid long continued volcanic action, and again to long periods of repose, and that the periods of activity and repose are·recurrent at long intervals of time? What the mountain chains of the world are in broadly parallel bands? What has caused the stratified rocks to be tilted from their original?

By T. F. Witherbee

IT is proposed to give, first, a description of the works ; second, a report of the first six months of the present blast; and third, such improvements as have been suggested by the practical working. The site selected for this furnace was, at the time of commencing work, October, 1872, entirely covered by the navigable waters of Lake Champlain. A coffer-dam was first built of cribs of round timber filled with stone, forming three sides, while the shore answered for the fourth. Considerable excavating was done with a steam-dredge, a hole being left for it to pass out. The opening was then built up, and the cribbing banked up with blue clay from the bottom of the lake, to render it water-tight and the dam pumped out; the remainder of the excavating being done by hand. All of the foundations, with the exception of the elevator-tower, and fifteen feet of the east side of hot blast, rest on the Potsdam sandstone, which forms the shore line, dipping into the lake at an angle of fifteen degrees. Owing to jogs in the formation, a much greater depth was found necessary than was at first anticipated, the foundation under the stack

Jan 1, 1876

In accordance with the new concept described in the paper presented at the TMS annual meeting in 1989, 1 a new zinc cellhouse was constructed and successfully operated. The new concept was proposed in order to reduce energy requirements and to mechanize the electrode handling in the cellhouse. Major modifications involved the use of an electrode unit consistfog of assembled anodes and cathodes with frame bodies between each cathode and anode. The space between a cathode and an anode could be halved by this unit structure. In this paper actual operation data are summarized and discussed in comparison with the calculated figures.

Jan 1, 1990

By Paul H. Johnson

The CH Leaching process is a new, more sophisticated, form of gold, silver, uranium and sulfide copper heap leaching wherein each layer of a multi-layered heap is divided into a number of independent cells, each of which are successively formed and leached in the top layer of the heap to their maximum economic recoveries, and then rinsed and sealed from further leaching. Triangular earth berms form the outside walls of the heap and a gridwork of rock-filled berms on top of the bottom pad form independent under- heap solution storage zones. The high degree of solution recirculation and staging that occurs in this process produces a relatively small volume of very rich pregnant solution. The cellular heap design and its mode of operation result in a uniform, intensive, long-term leach for all of the ore particles in the heap. Besides improved metal recoveries, the process appears to have several cost and operating advantages. In the CR2MR process, sulfuric acid and a soluble sulfide are added to a gold and/or silver pregnant leach liquor to precipitate most of the contained silver, mercury, copper, etc. as sulfides at a pH below 2.5. The other product of the reaction is solubilized HCN. Following a liquid-solid separation step, cyanide is regenerated in the supernatant solution by raising the pH to a level above 9.0. This process regenerates a portion of the cyanide used in the leaching step, removes contaminant ion species (silver, copper, mercury, etc.) from the leach solution and, in a subsequent step, recovers the gold in an enriched form. It is believed that substantial cost savings may be experienced by the use of this process in some gold and/or silver leach systems.

Jan 1, 1984

By Luis Elek

DEVELOPMENT of the cement industry in Mexico began some 40 years ago. It has gradually reached great importance in the economic life of the country and has contributed greatly to the technical and economical advances which have been so noteworthy, particularly during the last 15 years. From a modest start, the industry now comprises 18 cement-producing plants having a potential annual capacity of approximately 14 million bbl. About half the plants were built and equipped with second-hand machinery during the last world war when no new machinery could be procured. They will hardly attain full production before being modernized and reconditioned, a job now under way in several of the plants. At present, the yearly consumption is only about 8 to 9 million bbl but is steadily increasing. This is only a fraction of the cement consumed in the U.S.A., which is about 250 million bbl per year, although on the basis of consumption per capita per year, the figure is 1/3 bbl for Mexico and 1 2/3 bbl for the U.S.A. Cement consumption in Mexico is well above the average of all other Latin American countries, with the exception of the Argentine, and considering the potentialities and undeveloped riches of Mexico, the road construction and irrigation works, it is fair to assume that the Mexican cement industry will still prosper and expand in spite of temporary setbacks in the future caused by-local events of economic or political nature. Portland cement is manufactured by burning a mixture of raw materials, one of which is mainly composed of calcium carbonates and the other of aluminum silicates. The most typical materials answering this description are limestone and clay, both of which occur in Mexico in many varieties. To be usable for cement manufacture limestone should contain at least 77 to 80 pct calcium carbonate. Lower grade limestone can be used for cement manufacture only if the lime content is increased by the beneficiation process, which has not yet been adopted by the Mexican cement industry. Most of the limestone used by Mexican cement plants has a calcium carbonate content of 90 to 95 pct and therefore requires addition of one or several correction materials. A typical composition of raw mix for cement manufacture is 85 pct limestone and 15 pct shale, clay or volcanic materials. Occasionally it is necessary to add a smaller amount of sand or other siliceous material to increase the silica ratio in the raw mix. Likewise, it is sometimes necessary to add 1 or 2 pct iron ore to facilitate fusion in the kiln and to obtain proper relation between alumina and iron oxide. After calcining and

Jan 1, 1952

By Roy A. Grancher

HAPPY BIRTHDAY Not only is 1971 the Centennial Year of the AIME, but it also marks the One Hundredth Anniversary of the United States Portland Cement Industry. On September 26th in 1871 David O. Saylor of Allentown, Pennsylvania, received his patent Numbered 119,413 for the manufacture of portland cement. "Cement" had been used in the United States before that. This was, however, natural cement - a direct product of rocks as found in nature, usually burned at low temperatures in open kilns. During the early 1800s this natural cement played an important role in such projects as the building of the Erie Canal. It was only after the Civil War that small amounts of high priced portland cement was imported from Europe. The successful use of this material in construction led to Saylor's experiments and subsequent patent for the manufacture of a scientifically controlled product in this country. These one hundred years have witnessed four major "ages" of cement . . . three of them occurring in the last quarter century since World War Two. The first age was the "Age of Development", a seventy-year period which saw the growth of cement and its concrete end uses as major construction materials. Next followed a period called the "Age of Demand" when, after the war, cement became in short supply relative to large building requirements. In effect a cement shortage existed. The decade of the Sixties proved to be the "Age of Reaction", with its courses of action coming in response to the problems that arose when the industry's expansion programs provided too much capacity. Today cement, and the concrete industries, find themselves entering the "Age of Reason". Overcapacity, low price, rising costs, and poor returns are several of the reasons behind that name, As these industries face the construction challenge of the Seventies, and beyond, the application of basic management principles (otherwise known

Jan 1, 1971

A rotating disc geometry was used to provide a uniformly accessible surface for a kinetic study of the cementation of cadmium, lead, and silver from dilute aqueous solutions. This work is an extension of studies carried out on the Cu-Zn and Cu-Fe systems for which the reaction rate was found to be completely solution phase mass transfer controlled.When the amount of material deposited was greater than 0·2 to 0·4 mg/cm2 there was an apparent enhancement in rate which is attributed to the formation of a roughened deposit. This same phenomenon was observed in the Cu-Zn and Cu-Fe systems. Again, the rate of reaction of each system investigated was found to be solution-phase mass transfer controlled.

Jan 1, 1971

By Lawson F

A rotating disc geometry has been used to provide a uniformly accessible surface for a kinetic study of the cementation of the metals cadmium, lead and silver from dilute aqueous solutions. This work is an extension of studies carried out on the Cu/Zn and Cu/Fe systems for which the rection rate was found to be completely solution-phase mass-transfer controlled. When the amount of material deposited was greater than 0.2 to 0.4 mg/cm2 there was an apparent enhancement in e which is attributed to the formation of a roughened deposit. This same phenomeon was obseived in the Cu/Zn Cu/Fe systems. Again, the rate of reaction of each system investigated was found to be solution-phase mass ,..~sfer controlled.

Jan 1, 1970

By N. A. Sareyed-Dim

Nickel ores may be classified into two major categories : sulphide ores, and oxidized lateritic ores, these latter containing nearly 80% of the known reserves of the metal (1). Two types of lateritic ores are recognized; ores high in iron but low in magnesia and silica are known as "limonitic", while ores low in iron but containing high percentages of magnesia and silica are called "silicate" (see Table I). Sulphide ores can be beneficiated readily by conventional ore dressing techniques and the technology for nickel recovery from such ores has been well tested in a number of commercial processes (1-4). Unfortunately, no economically viable process for the concentration of nickel from low-grade deposits has yet been developed, and so only the high grade ores are able to be worked profitably. Silicate ores have been treated pyrometallurgically for the production of ferronickel (2) (3) (5); limonitic ores have been processed hydrometallurgically to produce nickel metal (2) (3) (6) (7).

Jan 1, 1975

By D Connelly

The Iron Road Limited Central Eyre Iron Project (CEIP) area, located on the Eyre Peninsula of South Australia, covers extensive Archaean iron formations that occur as coarse-grained magnetite bearing gneiss. The cumulative strike length, estimated from aeromagnetic data, is at least 95 km.The project is located in a grain growing area 185 km west of the existing iron ore and steel making operations of OneSteel at Whyalla. A narrow gauge railway built to transport agricultural products to the deep-water port of Port Lincoln, 175 km to the south, traverses the project area. A number of well-serviced rural townships are located nearby. Current activities include resource expansion drilling, extensive metallurgical test work, community consultation and a Prefeasibility Study (PFS) that commenced in April 2010.The PFS has encompassed the Central Eyre Iron Project, comprising the three significant iron occurrences (Warramboo, Kopi and Hambidge) and was completed in early 2011. Extensive test work programs and metallurgical modelling confirmed viable process options for the project, using simple off the shelf processing technology.Preconcentration by coarse cobbing yielded promising results, and is the key to reducing not only the capital expenditure but also the operating cost, in particular the power cost, which is the highest operating cost component of a magnetite benefi ciation plant. The ore is also amendable to high pressure grinding rolls (HPGR) processing. This offers a potential for further reduction of the energy requirements.Test work also confirmed that a high grade blast furnace quality concentrate (~68 per cent Fe) can be produced at a relatively coarse grind (P80 106 µm).

Jul 11, 2011

By Harrison Schmitt

SINCE the U. S. Geological Survey published the data on the Central Mining District collected by Lindgren and Graton1 and by Paige2 much new information has been obtained by development and mapping, but none of it had been published until recently when Kniffin3 published on Fierro, Lasky4 on the Ground Hog mine, Thorne5 on Santa Rita and Landon6 filed a thesis on the Fierro-Hanover-Santa Rita area at the Uni-versity of Chicago. During the years 1927-1930 much of the writer's time was spent in mapping the geology and ore deposits of this district, particularly in the area of the zinc deposits at Hanover. Some of the data collected are presented here. Previous publications have been freely drawn upon and additional data used that were generously supplied by L. M. Kniffin, Wilfred Wright and Gerald Ballmer. Thanks are due Augustus Locke, Samuel G. Lasky, Kniffin, Wright and Ballmer for suggestions and critical readings of the manuscript, and to the Empire Zinc Co. (a subsidiary of the New Jersey Zinc Co.) for the privilege of publishing material compiled largely at its expense. The relation of the Central. or the Santa Rita-Hanover-Fierro district to the Silver City district is shown on Paige's geologic map in the Silver City folio.7 Granodiorite porphyry and quartz-monzonite porphyry

Jan 1, 1933

By Percy A. Robbins

I. INTRODUCTION. THE central power-station. of the De Beers Consolidated Mines, Ltd., was designed and built under my supervision about five years ago. Since no detailed description of this plant has ever appeared, it may possess sufficient interest to warrant its publication, even at this late date. Although some additions may have been Blade to the plant, the following account, prepared from my notes, and accurate up to May, 1905 (at which time I severed my connection with the De Beers Com¬pany), will, I think, be found substantially correct. Certain local conditions governing the design of this plant should be stated first. If. GENERAL CONSIDERATIONS. The climate is hot and dry. The .region around Kimberley is arid and water is very scarce. The supply obtained from the mines contains so much material in solution that it is unfit for use in boilers or condensers (although tests recently made with a water-softening plant, built by Hans Reisert, of Germany, would indicate that water thus treated is suitable for boilers). And the amount of water required for concentrating about 30,000 tons of ore per day is so large that the question of adequate water-supply for this power-station had to be carefully considered. The rainy season extends from December to April, and the rainfall averages about 15 in. per year. Droughts are frequent; and in some years there is scarcely any rain at all. The water-supply for the town of Kimberley is brought from the Vaal river, 16 miles distant, and pumped into town by a private water company. The charge made for water, which is

Mar 1, 1908