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By Peter J. Stewart

My first experience with carbon reactivation in the gold industry was at Whim Creek, Meekatharra some 15 years ago. Very little was known, in fact, carbon reactivation kilns in the gold room were a complete mystery. Ten years ago at conferences such as this the mystery was more as to why field kilns would not reproduce activities achieved in the laboratory. A carbon reactivation kiln manufac­turer was thought to be brave or stupid to speak at a venue such as this. Reactivation kiln design has improved dramatically in the past 10 years and with a few exceptions, most kilns operate well. May I suggest that now, the focus is on plant practice rather than kiln design, and that the basics of plant practice as it relates to carbon activity needs revisiting. As metallurgists like to talk on engineering, accountants on the Economy and vice versa, my presentation on Carbon Reactivation will focus on plant design and operation as it effects carbon reactivation. There have been some excellent papers published over the past 15 years on the basics of carbon reactivation in relation to gold processingl,2,}. Taken that kilns operate and are effective to a greater or lesser degree, plant design and operating practise have an enormous bearing on carbon activity, solution tail, carbon loss and other cost items. This presentation will not argue the merits of equipment used for the thermal reactivation of organically fouled carbon, questions on this subject are welcome over a drink after this session.

Jan 1, 1995

By Hans von Michaelis

It is difficult to fail if one has a great deposit, but 'great' ore deposits are few and far between. More often one hears that a mine has been 'made' rather than found. This is particularly true for industrial minerals and for gold and silver projects. Even the best ore deposit can often be improved through innovative technology, e.g. the Escondida copper mine in Chile, where a novel ammonia leaching process is yielding a fabulous DCFROI. Consider the case of a small high grade gold mine. Previous owners had found inadequate reserves to justify the capital cost of developing the mine and installing a mill. Lower grade resources had been ignored because the owners were looking only for grades that would be high enough to support a small underground mine and mill. Randol, assisted by Kappes Cassiday & Associates, determined that the ore was amenable for heap leaching. Secondly, existing drillhole data indicated a significant lower grade resource that appears to be accessible to open pit mining methods. In this case, the appropriate selection of off-the­shelf technologies has literally 'made' the mine. At the Randol at Vancouver '94 conference on Latin American Mining Opportunities, papers on innovative technolo­gies for exploration, mining, metallurgy and environmental management were presented in non-technical terms for managers and resource developers. It was surprising how few of the exploration- and finance-oriented delegates participated in these sessions. Numerous technologies were presented that could be added to one's arsenal of tricks to 'make' a mine, i.e. to convert resources into ore reserves through knowledge.

Jan 1, 1995

By W. D. Grimsley, R. P. King, J. B. See

Samples (15 to 20 g) of pre-calcined Mamatwan manganese ore or pure Mn 304 smaller than 48 mesh were reacted at temperatures in the range 1000 to 1300°C with samples of spectrographically pure graphite smaller than 325 mesh. Samples (1 g) of ore or pure Mn02 smaller than 48 mesh were reacted at temperatures of 1000 and 1200°C with pure graphite fines in argon, with graphite in carbon, .'1onoxide, and with carbon monoxide alone. In each case, the loss of mass as a function of time was recorded with a hermobalance. The rate and degree of reduction were found to increase with additions of carbon and with increasing temperature up to 1300oC, when they reached their maximum. The shape of the reduction curves, together with the results obtained from examination of the products of reaction by microscopy and X-ray diffraction, were used as the basis for a postulated reduction mechanism. Some details are given of an initial kinetic model that was used to verify the proposed mechanism. It was found that the reduction of Mamatwan ore by graphite at temperatures in the range 1000 to 1300°C occurs in two stages: (i) an initial stage during which the higher oxides of manganese are rapidly reduced to MnO with concurrent formation of CaMn2O4 and (ii) a longer stage during which CaMn2O4 and MnO are reduced to carbides by carbon dissolved in the ferromanganese phase.

Jan 1, 1978

not weaken. I saw him shortly before he was killed; his conduct under fire was splendid and an inspiration to his men. His loss is felt deeply by all ranks. Thanks to him and to others, who like him, paid the full measure of devotion to their country, our line was held until the critical situation in that vicinity was at an end. He died the true death of a soldier, with his face to the enemy. As we now look back, it is easy to believe that this holding of the line of defense intact by General Carey and his men was a determining factor in the outcome of the war. To have played so important and noble a part in this vital effort as that taken by Perry is assuredly the privilege of few. Our lives, it seems, are like capital entrusted to us to be expended as wisely and effectively as we may. With them we purchase whatever of accomplishment the stuff that is in us permits. It is impossible to escape profound regret that a career so full of the highest promise, and a personality so overflowing with all that is fine and lovable, should have been cut short at the age of thirty-one. Yet who can doubt that in a few months Perry bought with his life the fullest achievement of a life-time—a glorious part in the salvation of Liberty and Justice and Decency, indeed of Civilization itself! L. C. Graton.

Jan 1, 1920

By L. W. Helle

In this investigation, which was conducted at the Metallurgical Research Plant, Lulea, Sweden, a series of experiments were carried out using a water-model to simulate the gas rinsing of a ladle containing liquid metal. The factors examined include the effect of gas flowrate, the position of a porous plug or lance, the immersion depth of the lance, and the geometry of the bath at the time of complete mixing. Mixing times were recorded by conductivity measurements. The results showed that there is a threshold level for mixing above which no advantage is to be gained from an increase in the gas flowrate. It is suggested that the results can be applied to rinsing ladles in working situations, the levels being approximately 270 dm3/min for 40 t ladles and 780 dm3/min for 150 t heats. The optimum siting of the lance or porous plug is a position that is three-quarters of the internal radius from the centre of the ladle with the lance penetrating as deeply as possible into the ladle. The best design of liquid bath is that having a diameter-to-height ratio of I. An equation was developed for the calculation, by dimensional analysis, of the time required for mixing during gas rinsing, and a comparison of the calculated mixing times with the results from production trials shows a satisfactory agreement (with a correlation factor of 0,91). Thus, an equation is available for the calculation of the stirring time needed to completely mix the bath in production situations.

Jan 1, 1981

By Roswell Johnson

THE Manual of the Oil and Gas Industry, under the Revenue Act of 1918, published by the Treasury Department for the guidance of oil companies in preparing their estimates of future recoverable oil for the purpose of calculating depletion, gives the first large public collection of comparative decline curves for the whole country. It is a matter of both scientific and practical interest to so arrange these data that the pools can be readily compared. There are certain difficulties in such a comparison, however: 1. The economic limit varies from 50 to 2000 bbl. a year in different pools taken. (2) Because of this variation in economic limit, the range of data shown makes comparison possible only for wells of intermediate size. In order to be as inclusive as possible, I have taken as an expression of the rate of decline the amount of oil produced in the period during which a well drops from 3000 to 2000 bbl. a year.. No period of smaller production could be used because of the high economic limit in California; and no period of larger production and yet include the small well areas of the Appalachian. As it is, the Lima-Indiana wells are excluded. In a few instances, curves were extrapolated to obtain the reading, where the curve seemed regular enough to warrant it. In general, the amount of oil, in barrels, produced while a well declined from 3000 bbl. to 2000 bbl. a year is shown in Table 1.

Jan 1, 1920

By S. L. Crouch

This paper describes a numerical procedure for the computation of the displacements and stresses induced by the mining of a tabular ore deposit in faulted ground. The numerical procedure is based on the displacement discontinuity method, which can be regarded as an application of Salamon's 'face element principle' to cases in which the reef plane is faulted into several sections, or even folded in an arbitrary way. An element of a fault is modelled in the same manner as an element of the reef, except that a fault element is allowed to undergo permanent inelastic deformation (i.e., slip) if the stresses transmitted through the fault-filling material satisfy a Mohr-Coulomb yield condition. An iterative technique for the incorporation of a Mohr-Coulomb yield condition in the general displacement discontinuity method is explained. This technique is illustrated by means of a simple example involving the mining of a flat-lying reef intersected by a fault. The displacements and stresses at selected locations along the fault are examined as the reef is mined, element by element. A consideration of the energy changes reveals that the occurrence of slip along a fault leads to a sudden increase in the energy release rate due to mining as the excavation intersects the fault. The energy release rate then falls off abruptly to a value less than that which would occur in the absence of any slip, and gradually builds up to re-establish the conditions that would exist in unfaulted ground.

Jan 1, 1979

I HAVE told you of two parts of the mould for guns. You lack the third, which is the one for making the breech. This, in addition to being a part that is always ornamented with some piece of sculpture to make the gun beautiful, is that part which forms the bottom and closes the whole mould. It is also the one that sustains the entire burden of the bronze, and it must therefore be made with great consideration and diligence, taking care to make it strong with clay and with iron bands. Various methods are used in making this. Every master does as he knows how, either preferring to do it quickly or delighting to make his work ornate and beautiful. His choice also depends on whether they are to be just artillery or occasions for artistry. There are some who, if the guns are of a round form, make the pattern for the breech on a lathe, either of wood or of clay. If they are fluted, they make the flutes by hand in wood or clay, following the pattern of the board. In a part that perchance might not come out of the mould, they put some tallow underneath or make it entirely of tallow or wax so that it will come out. Likewise, if they wish to make cornices or other projections these can be put on either in wood or in clay. In the same way they also apply leafwork of clay or wax so that it can be taken out by hand or with the fire.

Jan 1, 1942

By James J. Brady

The basic story at Bear Swamp was how to excavate an underground chamber 79 feet wide by 227 feet long and 150 feet high, along with the related access, tarbrace, leads, power tunnels and shafts, do it under cost and ahead of schedule and still have just about everybody love you. The isometric sketch of the overall project follows. I won't go into any of the details of the physical scope at this point. Instead, we'll bring out the sizes, grades, particular problems of the different areas as we cover them. First of all, let's establish that Bear Swamp was a Target Estimate - Fee with Incentives type of contract. Gates and Fox's contract was with the project's general contractor, J. A. Jones. We were one of three contractors who submitted proposals and estimates to Jones. After much negotiation and many submittals, Gates and Fox was notified we had been selected to do the underground excavation on April 12, 1971. We had our first people back on site in two days, set up a temporary office, made our first steel order for jumbo erection, pacing our jumbo construction to meet the date when J. A. Jones would have the access portal ready for us. The shops, yards, dry house, compressor building were all erected as sites were designated for our use. At last, on Thursday, June 3, we trimmed the face and moved our 9-machine Euclid jumbo up a hastily constructed haul road and started our portal preparation of the access tunnel.

Jan 1, 1974

not weaken. I saw him shortly before he was killed; his conduct under fire was splendid and an inspiration to his men. His loss is felt deeply by all ranks. Thanks to him and to others, who like him, paid the full measure of devotion to their country, our line was held until the critical situation in that vicinity was at an end. He died the true death of a soldier, with his face to the enemy. As we now look back, it is easy to believe that this holding of the line of defense intact by General Carey and his men was a determining factor in the outcome of the war. To have played so important and noble a part in this vital effort as that taken by Perry is assuredly the privilege of few. Our lives, it seems, are like capital entrusted to us to be expended as wisely and effectively as we may. With them we purchase whatever of accomplishment the stuff that is in us permits. It is impossible to escape profound regret that a career so full of the highest promise, and a personality so overflowing with all that is fine and lovable, should have been cut short at the age of thirty-one. Yet who can doubt that in a few months Perry bought with his life the fullest achievement of a life-time—a glorious part in the salvation of Liberty and Justice and Decency, indeed of Civilization itself! L. C. Graton.

Jan 1, 1920

By Pramod C. Thakur

Tunnels are defined as underground passages made without removing the overlying materials. From time immemorial men have driven tunnels for mining purposes. Even today tunnels are the building blocks for underground mines. The total length of such a network of tunnels in a mine may add up to 10-100 miles! In addition to this, rapid development of vehicular traffic, needs for air raid protection and metropolitan traffic problems have given a great impetus to underground tunnel construction. But for the successful drivage of any tunnel an adequate air environment has always been and remains an essential prerequisite. This is particularly true for tunnels in mines which are driven in gas bearing strata often at a substantial depth from the surface. An adequate air environment is designed to promote the health, safety and comfort of workers which results in greater productivity and efficiency. Its legal definition varies from country to country but, in general, it means the provision of sufficient circulating air, often at specified velocities, to maintain: (i) at least 19% oxygen in the working areas (ii) Concentration of pollutants, e.g., methane, carbon monoxide, respirable dust, etc. below specified limits. Table 1 shows the maximum allowable concentrations for some of these pollutants.1 (iii) Temperature and relative humidity below specified limits. Ventilation of tunnels in mines assumes ever. greater importance today because of increased mechanization and concentration of output which leads to higher rate of production of inflammable gases and respirable dust. Efficient management of the tunnel air environment, however, depends heavily on a thorough knowledge of how

Jan 1, 1974

By John Chipman, Daniel Dutilloy

The equilibrium of gaseolis H2O-H2 mixtures with liquid iron-phosphorus alloys in the range 0 to 3 pct P is used to establish the increuse of the activity coefficient of oxygen, in the presence of phosphorus. Two different sampling techniques are used. THE importance of oxygen as a refining agent in steelmaking operations makes it desirable to improve our understanding of its behavior. Phosphorus which is always present in the ores has adverse effects on steel properties and its removal is necessary. The present study was undertaken to evaluate the interaction of oxygen and phosphorus in molten iron. Bookey, Richardson, and welch1 have studied the phosphorus-oxygen equilibria in liquid iron in the presence of lime. They used a mixture of hydrogen and water vapor to control the oxygen potential and worked with crucibles made of tetracalcium phosphate and lime. At low phosphorus concentration, i.e., at high oxygen, they observed a marked deviation in their results. They tentatively ascribed this to a large negative effect of oxygen on the activity of phosphorus. This was then included by chipman2 in his review of interactions in liquid iron. Pearson and Turkdogan 3 have later reported an interaction parameter They equilibrated a mixture of hydrogen and water vapor with an iron-phosphorus alloy contained in an alumina crucible and sampled the melt by suction in a silica tube. The solubility of oxygen in iron-phosphorus alloys has been studied by Levenets and Samarin.4 They reported an interaction parameter

Jan 1, 1961

By Robert D. Talvensaari

It is indeed an honor for White Pine, as a member of the copper mining industry, to participate in this Rapid Excavation Conference. Although our presentation, as the title indicates, is not a success story, we foresee, through our experience, future application of boring machines and rapid excavation equipment in the hard rock mining industry. One might ask what a copper mining company would be doing with boring machines and why the gamble on a high-cost, capital investment for a relatively untried application. Perhaps a little background on the White Pine mine and its geology will explain our daring and speculative motives. THE WHITE PINE MINE The White Pine Copper Company, a wholly-owned subsidiary of Copper Range Company, operates a mine, mill and smelter at White Pine, Michigan in the western Upper Peninsula approximately 6 miles due south of Lake Superior. We employ approximately 3,000 people from the surrounding area and mine approximately 25,500 tons of low grade (1%) copper ore per day. The orebody is contained within several distinct sedimentary horizons that comprise the lower 20 feet of a Precambrian formation known as the Nonesuch Shale. Numerous articles and reports have described many aspects of the White Pine operation and the geology. I will brief you only on that criteria which precipitated our interest in rapid excavation equipment and techniques, specifically, boring machines. Mineralogical and optical studies have demonstrated that the siltstones, sandstone and shale beds all contain relatively barren and discrete particles of quartz (25%), feldspar and mica, bonded with

Jan 1, 1974

By F. A. Forward, J. Halpern

A new process is described for extracting uranium from ores containing sulphidic minerals, which comprises treating an aqueous pulp of the ore with air or oxygen at elevated temperatures and pressures. The acid required to dissolve the uranium is generated during the leach through oxidation of the sulphides. The chemistry of the process is discussed and laboratory results are presented to illustrate the operation of the method and the variables which control it. With most ores, leaching at a temperature of 130°C and an oxygen partial pressure of 10 psi provides uranium extractions of 90 to 95 pct in 4 to 6 hr. The acidity and level of dissolved impurities in the leach liquor can be kept fairly low. The method is characterized by a number of advantageous features including low reagent cost, short retention times, and high recoveries. RECENTLY there have been developed several processes for extracting metal values from ores by pressure leaching techniques;' -' an example is the carbonate leaching process for uranium ores which has been studied in this laboratory.' Leaching is carried out under oxygen pressure to ensure oxidation of the uranium to hexavalent compounds which are soluble in carbonate solutions. During the course of investigations relating to this process, it was observed that sulphide minerals, such as pyrite, usually were oxidized under the conditions of the leach treatment resulting in the formation of iron hydroxides and sodium sulphate, i.e. 2 FeS= + 7Vz O2 + 8 Na,CO3 + 7 H,,O -* 2 Fe(OH)3 + 4 Na2SO4 + 8 NaHCO.,. [1]

Jan 1, 1956

By E. L. Bruce

THE district of. Patricia, in the province of Ontario, lies northwest of the Albany River and extends northward to Hudson's Bay. Formerly this was the unorganized district of Keewatin, the southern part of which was divided in 1912 between the provinces of Manitoba and Ontario. The interprovincial boundary now runs north from Lake of the Woods for 275 mi. and thence northeast 375 mi. to Hudson's Bay. This district is comparable in size to all the older part of Ontario south of the Canadian Pacific Railway east of Lake Huron-thus it is roughly one-third of the whole of the present provincial area. The central part of this great triangle is one of the least accessible parts of Canada. From it streams flow southward to the English River, southeastward to the Albany, northward to Hudson's Bay and the Hayes River, and westward to Lake Winnipeg. None of the streams is large and canoe travel is not easy. The only industry it has ever had is the trade in furs. Until the development of the airplane on a commercial basis, the only means of travel was by canoe or dog-train. There is not a mile of railway in the whole district. The two areas to be dealt with lie in the southwestern part of Patricia. Red Lake is 50 mi. east of the Manitoba boundary and 75 mi. north of the transcontinental railway from Cochrane to Winnipeg. Woman Lake is 50 mi. farther east and slightly farther north. The late Dr. D. B. Dowling, of the Geological Survey of Canada, visited Red Lake and spent some time there during his exploration survey from Lac Seul to Berens River in 1893. He also visited the Woman Lake basin during the same journey, but his examination of it was much less detailed, the great area covered by him during the one field season making it impossible to make more than a hurried reconnaissance. Some prospecting in the Red Lake district followed Dowling's exploration, but the distance from railway was too great for any systematic work to be done.

Jan 1, 1928

By David deVries, James Rajith, Paul Mascrenhas, Nurzhan Dyussekenov, Lawrence Hanschar

Kansanshi Copper Smelter commenced operation in March 2015. The smelter features four Peirce- Smith Converters (PSCs) operated in a three hot, two blowing configuration. This paper describes some of the process automation and design features implemented to maximize operational and environmental performance. To ensure that the converters were easy to operate, efficient, and were protected in emergency situations such as power failures or loss of tuyere air supply a significant focus was placed on automated sequences initiated by “one button” operator commands or otherwise automatically by the Distributed Control System (DCS). Examples include: main converter roll-in and roll-out sequences; emergency roll-out in the event of power failure; and the charging sequences for reagents (silica and reverts). Other automated features configured for the PSCs were specifically aimed at maximizing converter capacity and reducing the environmental impact from fugitive emissions. These features include: “one button” in-stack charging; automated restriction of blowing rate based on the available acid plant capacity; and fully-automated control logic for the Secondary Ventilation System. In-stack charging allows anode furnace oxide slag to be poured into the PSCs while the converters are still blowing and still sending off-gas to the acid plant. PSC Secondary Ventilation control logic was configured to require minimum input from the operators while ensuring maximum utilization of the available draft from the ventilation system. Highly automated PSC controls contribute to high utilization, averaging 41.2 in-stack hours per day. INTRODUCTION Kansanshi Copper Smelter (KCS) is located near Solwezi at Kansanshi copper mine in Zambia's Northwestern province. The smelter treats concentrate produced at Kansanshi mine as well as Sentinel mine located 150 km west of Solwezi. Four Peirce-Smith Converters (PSCs) are installed at KCS. The nominal capacity of each converter is to treat 350 t of copper matte and produce up to 250 t of blister copper per batch. Normally three PSCs are hot, with two able to operate (produce off-gas), and the third converter on hot standby. The fourth converter is normally under cold repairs. The blister charge size is relatively low for the matte charged due to the unavailability of tank house or other high copper scrap.

Jan 1, 2019

By Warwick D. Bullen

Gold mining in the Yellowknife area of the Northwest Territories started long before the concept of sustainability entered the academic literature and by the time the term enjoyed widespread public acceptance, the Yellowknife gold mining industry was in its sunset years. Nevertheless, the city of Yellowknife will long outlive the gold mines that it was founded on, demonstrating that not only can mining build sustainable communities, but that sustainable mining as a concept is an entirely valid precept. To this effect, the authors examine the complex economic and social aspects of the gold mining industry in the Yellowknife area over the last 70 years.

May 1, 2004

By W. B. Plank, A. C. Callen

WAR and normalcy do not walk hand in hand, whether it be in industry, the educational field, or in the daily lives of individuals. Schools and departments offering curricula in mineral engineering have been seriously disrupted, beginning with 1942 and reaching a low during 1944. Selective Service regulations and voluntary enlistments have effectually stopped the flow of college-trained men into the mineral industry, and the flow into the colleges is little more than a dribble. The year just closed has been a most serious one for our institutions. Until March many of our faculties had been kept reasonably intact because of the large training programs of the Army and Navy. Although the number of

Jan 1, 1945

By L. B. Phelps

Industrial mineral production is basic to life in these United States. Production techniques of these minerals are part and parcel of the training that mining engineering educators must, and do, impart to their students. This paper deals with the basic mining engineering program required by all accredited engineering schools and the specific way the Pennsylvania Scare University presents and builds upon them. The manner in which these concepts provide the student with the necessary tools to function as a mining engineer in me realm of industrial minerals extraction is discussed.

Jan 1, 1981

By F. B. Plummer

GEOLOGICAL engineering as applied to oil fields, or production geology as some prefer to designate the profession, is designed to fill in the border line between pure geology and pure petroleum engineering. Therefore the production geologist may, and frequently does, reach out to grasp much in both professions. Where once the oil geologist was content to pick samples out of a mud ditch and try to identify oil formations from the color or appearance of flakes of rock bailed out of a well, now he has to deal with graphic electrical logs obtained by intricate and highly technical electrical apparatus and to make exact determinations to the fraction of an inch of the depth and thickness of an oil sand 2 miles below the surface.

Jan 1, 1944