Search Documents

By Franklin Moeller

THE application of electric power for driving, mine hoists handling heavy loads at high speeds has recently been extended by the installation of what is probably the largest electrically driven hoist in this country at the Granite Mountain shaft of the North Butte Mining Co., Butte, Mont. While the weight of rock which is hoisted by this machine is not the largest now being handled by electric mine hoists, the speed of hoisting is so, and the combination of the high speed with the heavy load has resulted in a machine of considerable interest to all those actively engaged in mining. Aside from mere consideration of size, this installation deserves attention because of the careful attention given, not only to the question of economy of operation, but to the details of construction and installation of the entire equipment. The conditions to be met in this installation were as follows: Weight of rock to be raised per trip, 7 gross tons 15,680 1b. Weight of skip 8,0001b. Weight of cage 1,8001b. Maximum depth of hoisting 4,000 ft. Diameter of rope 153 in. Total weight suspended on one rope from drum 42,000 1b. Normal hoisting speed 2,700 ft. per minute. Maximum hoisting speed : 3,000 ft. per minute. Desired capacity-200 tons per hour from 4,000 ft: depth. The ore is mined in several levels and hoisting is carried on from the 800-ft. level down to the 2,700-ft., which is at present the maximum depth from which the ore is raised regularly. Development is proceeding and a depth of 2,900 ft. has already been reached. The rock is handled underground in cars holding ¾ ton, and about 10 cars are the usual load for a skip. All of the ore is clumped into underground bins, which are of different capacities varying up to 250 tons. From the bins the ore is fed into the skips without passing into measuring pockets. At the surface the

Jan 2, 1916

By John T. Norton

In recent years, the damping capacity of metals has come to be recognized as an important index of certain types of structural change. In a number of instances, this property has proved to be particularly sensitive, but insufficient work has been done to permit a general interpretation. There is considerable question at the present time as to just what factors are responsible for the internal dissipation of energy when a metal is carried through a cycle of stress, and these factors must be ascertained if the value of the damping method as a metallurgical tool is to be determined. Since internal stresses are among the chief causes of dissipation of internal energy, or damping capacity, it was thought that a study of the changes in damping during the recovery and recrystalliza-tion of a cold-worked metal might throw some light upon the subject, particularly if the damping changes were correlated with other properties that are better understood. Probably more work has been done on the recrystallization phenomena of alpha brass than on any other metal, so this was chosen as the material for the present investigation. Damping measurements on brass have been made by Förster and Köster.1 They showed that the annealing of a brass that had been cold-drawn to 50 per cent reduction produced a rapid fall in the damping, a flat minimum occurring at approximately the temperature of recrystallization. The damping remained at a low value until grain growth was well under way and then it increased rapidly with increasing grain size. Köster and Rosenthal2 continued the work in greater detail. They pointed out that the damping decrease does not correspond to the hardness drop but occurs at a lower temperature, suggesting that the relief or redistribution of internal stresses has a large effect while the actual recrystallization effect is small. They also show the increase in damping at the higher annealing temperatures. Their curves are reproduced in Fig. 1.

Jan 1, 1940

By Mozley R

Contaminated sediments are a multinational problem. A crucial factor in solving an environmental problem is knowledge of, not only the amounts of polluted soil, the contaminants involved and their concentration, but also the historical background of the problem. Processing polluted soil is a tailor made activity based on rational decisions resulting from a detailed treatability study. Lack of information about characteristic properties of a specific sludge/pollution combination is the main obstacle in the route from first ascertaining that a particular harbour subsoil is polluted, to final identification of the full scale treatment plant. In the first instance, information must be generated regarding the distribution of pollutants in relation to the distribution of the original geophysical components. Based on this information rational decisions can be made on separation at a particular cutpoint and what sequential techniques should be involved for a certain fraction. For this purpose a `fingerprint method' is presented especially developed for investigation of polluted soil and sediments. The heart of the fingerprint method is a series of sequential hydrocyclone separations, by which a series of products is generated. The objective of the fingerprint method is to select an optimised treatment procedure in which the pollutants are concentrated in as small a volume of material as possible, leaving the bulk of the material clean. The pollutants can then readily be destroyed or isolated from the environment. The philosophy and advantages of the fingerprint method are demonstrated for a harbour sludge containing heavy metals as main pollutants. Hydrocyclone separation combined with flotation of both the coarse and fine fraction resulted in reusable and dischargeable products. Flotation of the fraction of fines was carried out by means of an experimental flotation cyclone enabling the selective recovery of mineral particles with diameters less than 10 microns. The overall conclusion is that design and engineering of treatment flow schemes for polluted dredged materials is a tailor made activity based on rational decisions resulting from the fingerprint information.

Jan 1, 1993

By Blamey Stevens

(Butte Meeting, August, 1913.) THE following paper aims to make a full explanation of the phenomena of rock jointing: It may be unnecessary to give any general description of what are termed joints in rocks, but Professor Geikie's clear and faithful generalizations are so illuminating that no excuse need be given. for introducing the following and other quotations into this paper "Almost all rocks are traversed by vertical or highly inclined divisional planes termed joints. These have been regarded as due in some way to contraction during consolidation (fissures of retreat) ; and this is no doubt their origin in innumerable cases. But, on the other hand, their frequent regularity and persistence across materials of very varying texture suggest rather the effects of internal pressure and movement within the crust." 1 General Explanation.-In this paper I show that the phenomenon of jointing may to a large extent be accounted for by the pressure of the water contained in the pores of the rock. To understand this, each constituent grain of the porous material may be considered to be separately compressed by the water which submerges it. As all the grains are held together by cohesion, the whole mass is contracted by this pressure. In an indefinitely extended mass, however, there must be a limit to the possible contraction without rupture, because the material is restrained from moving freely by other material around its boundaries. The mass of rock thus becomes broken up. This phenomenon is known as '" shrinkage " jointing. The term " shrinkage " is an apt one, if it be understood that the shrinkage of the rock is often brought about by change of stress. Stresses.-The compressive component of water stress on the individual grains is evidently the same as that of the water with which it is in contact. This is so, both before and after the jointing is formed. Before the jointing is formed there is, however, a tensile stress in one or more directions which keeps the material from contracting. .

Jan 7, 1913

By N. E. Holden, R. R. Goodrich

TheRe is a small area about Murray where bedded gold quartz veins occur in Prichard slate. The ore taken from the upper levels, during the early days, was free milling and was treated by stamp milling and amalgamation. There was likewise a considerable placer working. The report is current that tungsten (scheelite) was encountered, which interfered with the amalgamation in the stamp mills and which, in placering, collected in the riffles in the sluice boxes and clogged them. Consequently, in the quartz mines, the scheelite, when encountered, was rejected, being thrown into the waste, sometimes inside the mine and at other times outside on the dump. The free surface ores became worked out and as the ore in depth became pyritic and rebellious to amalgamation the mines closed down. Last spring tungsten ore brought a high price, near $80 per unit, 60 per cent. W03 and up. This so stimulated the output of tungsten ore that old dumps were explored and waste stored in the mines was gone over. Tungsten was likewise mined from virgin ground. So the district produced quite heavily for a time. The condition now is different. The price is not so high, about $20 per unit WO3, which makes profits questionable when mining in new ground. The accumulations from early day mining have been exhausted and the output has greatly declined. The Golden Chest mine was the heaviest producer of tungsten. The months of June and July were spent at this mine studying the problem. Since the mine had produced both gold and tungsten, we looked forward to the problem of recovering both from what might be called a gold-tungsten ore. A study of the Golden Chest vein showed this was not to be the case. While gold ore and tungsten ore come from the same vein, the tungsten ore is confined to a more or less disturbed or distorted portion

Jan 1, 1918

By Alexander Gakner

Since the end of World War II the Soviet Union has made great strides toward economic development of the country. Today it is firmly established as the world's second largest industrial power after the United States and it has committed itself before the people on both sides of the Iron Curtain to catch up with and to overtake us within a few decades. No nation could achieve such a degree of industrialization or aspire to become the world's industrial leader without a large supply of many basic mineral raw materials or at least easy access to such resources. In addition, it requires technical competence, a large skilled labor force, and a high rate of capital investment. Why should we concern ourselves with these Soviet aspirations? The Free World's yardstick of measuring a nation's well-being is the standard of living of the people in that country. Presumably even Communist governments are committed to some, however gradual, improvement in the standard of living of their people. The population of the USSR is 20 pct greater than that of the United States. Hence, if they ever achieve a standard of living equal to ours, they must by all logic reach a greater overall industrial output. However, in the U.S.S.R. the standard of living of the masses has not kept pace with the expanding industrial production and is still far behind that of the United States. Our concern, therefore, is with what the USSR intends to accomplish with its expanding industrial power: Will they produce large mineral raw-material surpluses and manufacture products to compete with us for world markets and attempt to put us out of business if not use it directly to wage war; or will they use their resources merely to produce more consumer goods for the Soviet people; or will they, along with other Communist nations in the not-too-distant future, compete with us for the world's sources of mineral raw-materials to maintain a high level of mass consumption?

Jan 6, 1960

By C. R. Austin

Tan investigation described in this paper deals with the development of high-temperature alloys of the Konel series over a considerable period of time at the Research Laboratories of the Westinghouse Electric and Manufacturing Co. The word "Konel" has been coined to designate a class of alloys which are essentially nickel-cobalt-iron with other elements added, usually in small quantities. Most of these alloys contain titanium, usually about 2.5 per cent. The main consideration related to strength at high temperatures but the thermionic characteristics of the alloys was also of considerable importance. It is, however, with the mechanical properties at elevated temperatures that we are herein concerned. Much attention has also been devoted to their age-hardening characteristics. There is little need to stress the utilitarian aspect of this subject, as it has been discussed frequently. Alloys exhibiting superior properties at normal or elevated temperatures rapidly find many suitable applications. There may be some question, however, as to what constitutes a "superior alloy, " or an alloy that may have good service possibilities at high temperatures. The problem is complex and various means have been employed to predict the useful life that may be expected of a material. In recent years the "creep limit" has been used as the best means of evaluation. Such tests necessarily are prolonged and hence collection of data is very slow. In a general survey of many alloys therefore the creep test is not desirable and recourse must be had to much shorter time tests in order more rapidly to select alloys which appear to show promise. For this reason the present survey has been made using the high-temperature tensile test and a bend test developed by Howard Scott.1 In the tensile test the conditions have been standardized for all tests, so that values obtained are at least comparable, one alloy with another, although the absolute values recorded merely indicate the mechanical properties at the given temperature under a definite rate of loading.

Jan 1, 1931

By C. Y. Wang

China now leads the world in antimony production, having contributed during recent years something over 60 per cent. of the world's production. The history of the antimony industry of China dates back to 1897 when the Tai Shing Co. was formed, under contract with the Hunan Bureau of Mines, for the smelting of the ore to crude; and in 1908 the Wah Chang Mining & Smelting Co. was formed for the smelting and refining of the ore and crude to regulus. The writer was then asked to take charge of the erection and control of this first plant for regulus production in China and has, since then, been more or less connected with the antimony industry in this country. This paper contains the results of many years' experience in connection with the Wah Chang Mining & Smelting Co., Changsha; the Pao Tai Mining & Smelting Co., Wuchow; the Loong Kee Smelting Works and the To-Cheng Smelting Works, Hankow; as well as information gathered from various other small smelters, scattered in different parts of the Provinces of Hunan, Hupeh, Kwangsi, and Kwangtung. An idea of the growing importance of regulus production in this country can be gleaned from the fact that, within a period of about 8 years, the export of regulus from Hunan alone jumped from 3 tons in 1908 to about 6000 tons in 1915; that a production of about 23,000 tons of regulus per year could easily be effected from all the smelters, as tabulated below, most of which were erected a year or two ago under the stimulus of the war booms, if the price at Hankow were to stay somewhere about $900 (Mexican) per ton, half of what it was at its height, thus enabling the utilization of ores from the hinterlands of the provinces; and even under the present ruling of prices and the closing of the less favored smelters, the production of regulus should not be less than 12,000 tons per year.

Jan 1, 1919

By J. E. Johnson

OF the many items of information necessary to the successful management of the blast-furnace, few are more important than knowledge of the location and movement of the stock: line:—whether the furnace is full and has been kept so; whether the stock is settling regularly or slipping; and, if slipping, how often it has slipped, at what times, and how far at each time. To obtain these data, a man is sometimes stationed at the top of a pair of mechanically-filled furnaces, sim-ply to watch and gauge them by hand in the old-fashioned way. A more recent practice is the suspension of test-rods from ropes leading over pulleys to the ground-level, where the ropes are mound on small drums with graduated peripheries and provided with crank-handles, whereby the skip-man or some other person can quickly and conveniently gauge the position of the stock-line in the furnace. I believe the credit for this great improvement belongs to Messrs. McClure $ Phillips of Sharon, Pa., who were, as far as I know, the first to apply it, and who have a patent for it. The valuable indications gained by application of the Uehling pyrometer to the down-comer are not to be ignorcd; but the information thus furnished is somewhat indirect, and there is no scale for the translation of " top-temperatures " into " feet down." Moreover, this apparatus, as a whole, is delicate, and the cost of installation and maintenance is high. If the record furnished by the Uehling pyrometer is not in the most desirable form, the test-rods, on the other hand, give no record at all, except through the memory or notes of a man who, to say the least, is not gauging continuously, and who may omit to report an improperly low stock-line, if it be due to a fault of his own.

Jan 1, 1906

By William B. Phillips

The concentration of natural magnetites has been carried on in this country for several years, and more or less information has been collected on the subject. Various inventors, availing themselves of the magnetism which is inherent in such ores, have devised machines for separating the impurities from the ore by means of the electric current; and a greater or less degree of success has rewarded their painstaking and persevering efforts. We are now fairly in position to judge of the value of the process as applied to such material. It is not my purpose to speak of this matter further than may be required by the emergencies of the case. I shall assume that most engineers and metallurgical chemists are already acquainted with what has been done at the Chateaugay mines, at Mineville, at the Benson mines, at the Weldon and Ogdensburgh mines, and at Cranberry; although, at this latter place, there has not been so much done as we could wish. I shall not now speak of the various types of separators. From the time of William Fullarton, to whom was granted an English patent, in 1792, for separating iron-ore by the application of magnetic attraction, down to the present time, a great. many devices have been suggested, and a great many patents taken out for this purpose; but it is not necessary now to enter upon a discussion of their merits. Perhaps, at some future meeting of the Institute, after we shall have experimented further with some of the machines on the market, there may be an opportunity to contribute something to the current knowledge of the efficiency and economy of separating-machines. In this paper I propose to give, as briefly as possible, the results already reached in converting a non-magnetic ore into magnetic ore, and then concentrating it over a magnetic separator of the alternate-polarity type. I am aware of the work

Jan 1, 1896

By G. S. Scott, H. G. Turner, W. L. Kleene

It is well known that different forms of carbon show differences in chemical behavior under apparently identical conditions. It is fairly well known that these differences persist, although to a lesser degree, in a single group of carbons, such as the anthracites of Pennsylvania. It is the purpose of this paper to show the extent of these variations for Pennsylvania anthracites from actual quantitative measurements of the amount of carbon dioxide reduced under the standardized test conditions employed. As the amount of carbon dioxide reduced to the monoxide (under comparative conditions termed, for convenience, the "reactivity") is important in combustion, gas production and metallurgy, it is hoped that this paper will be a useful contribution to the store of knowledge on these subjects. In carrying out the investigation, considerable time and thought were spent in obtaining what seemed to be the best possible design of apparatus. The next step consisted in making a number of trial runs on the same sample, varying temperature, particle diameter, etc. and then outlining a standardized procedure to be followed in testing all samples. Fifty anthracites were tested. As a matter of interest, some 10 miscellaneous samples were also tested. The data show initial reaction temperatures (abbreviated I.R.T.), reaction velocity constants at 900" and 950" C., some effects of added substances, and a few additional tests designed to throw some light on the causes of differences in reactivity. The sample of charcoal, as was anticipated, proved to be easily the most reactive of any sample tested. The anthracites as a group came second. The five samples of gas and by-product cokes, obtained from five different coke manufacturers, came third, and a single sample of Rhode Island anthracite ranked fourth, with respect to reactivity as above defined. Although the five coke samples do not necessarily represent the average market coke, and five samples constitute a rather small number of samples to serve as a basis for comparisons, the fact that none

Jan 1, 1934

By C. D. Gilpin, Franklin Moeller

The application of electric power for driving mine hoists handling heavy loads at high speeds has recently been extended by the installation of what is probably the largest electrically driven hoist in this country at the Granite Mountain shaft of the North Butte Mining Co., Butte, Mont. While the weight of rock which is hoisted by this machine is not the largest now being handled by electric mine hoists, the speed of hoisting is so, and the combination of the high speed with the heavy load has resulted in a machine of considerable interest to all those actively engaged in mining. Aside from mere considcration of size, this installation deserves attention because of the careful attention given, not only to the question of economy of operation, but to the details of construction and installation of the entire equipment. The conditions to be met in this installation were as follows: Weight of rock to be raised per trip, 7 gross tons........... 15,680 1b. Weight of skip.......................................... 8,000 1b. Weight of cage.......................................... 1,800 1b. Maximum depth of hoisting.............................. 4,000 ft. Diameter of rope.......................................... 15/8 Total weight suspended on one rope from drum............. 42,000 1b. Normal hoisting speed.................................... 2,700 ft. per minute. Maximum hoisting speed.................................. 3,000 ft. per minute. Desired capacity-200 tons per hour from 4,000 ft. depth. The ore is mined in several levels and hoisting is carried on from the 800-ft. level down to the 2,700-ft., which is at present the maximum depth from which the ore is raised regularly. Development is proceeding and a depth of 2,900 ft. has already been reached. The rock is handled underground in cars holding % ton, and about 10 cars are the usual load for a skip. All of the ore is dumped into underground bins, which are of diffcrent capacities varying up to 250 tons. From the bins the ore is fed into the skips without passing into measuring pockets. At the surface the

Jan 1, 1916

By Cyril Smith

ALTHOUGH not of the same importance as electrical conductivity, the capacity for conducting heat is nevertheless a very important property of metals and alloys. A knowledge of thermal conductivity is of value in selecting alloys for many purposes and in the calculation of the efficiency of apparatus which is being designed. Unfortunately, the determination of thermal conductivity is extremely slow and tedious, consequently few data have been obtained. A further reason for the lack of information is that there has long been an impression that the thermal conductivity of an alloy is directly proportional to the electrical conductivity and that it can therefore be calculated from the latter. The Wiedemann-Franz-Lorenz law of constant ratio of the two conductivities holds with a considerable degree of precision for all the pure metals, but appreciable deviations occur in certain alloys-particularly those containing nickel-and it seems difficult to predict exactly what the ratio will be. Therefore direct determinations of thermal conductivity should be made whenever the results are, needed with any accuracy. This research is intended eventually to cover all the alloys of copper that are of commercial importance, including the binary alloys of copper with zinc, tin, aluminum, nickel, silicon, manganese, cadmium and phosphorus, and the ternary alloys copper-nickel-zinc, copper-nickel-silicon, copper-manganese-silicon, copper-zinc-tin, etc. Most of these alloys are customarily used in the wrought condition and therefore were tested in the form of annealed rods. A limited number of sand castings were also obtained and examined. This paper contains a complete review of all the previous work that has been done on copper alloys, and includes a detailed description of the apparatus and method of procedure used in the present research, together with the new results obtained on the copper-zinc series, which is the only one completed at the present time. Subsequent papers describing the other alloys will contain the experimental results and discussion only.

Jan 1, 1930

Good morning ladies and gentlemen, and may I extend a particularly warm welcome to our shores to those of you who have travelled from overseas to attend this conference. I trust that you will find your visit to New Zealand both rewarding and enjoyable.   This is now my fourth appearance at a New Zealand minerals conference, the second of which has been jointly co-hosted by AusIMM and Crown Minerals. Since taking on the role of Associate Minister of Energy, I have had the opportunity to meet most of the industry players, and to visit a good number of the major mining operations. Through all of this I have become increasingly aware of not only how dynamic the minerals and coal industry is but also the array of factors that affect investment decisions in this business. Many of these factors, such as commodity prices and availability of investment funds, are determined primarily on the international stage. Others however, such as the allocation, regulatory and the fiscal regimes for minerals, are closer to home and are directly influenced by government policy decisions. I will talk more on what the government proposes in this area shortly.   But first, I would like to commend you all on your industryÆs continuing contribution to New Zealand Æs economy. 2004 has seen New Zealand Æs mineral and coal output top $1 billion for the second consecutive year. To put this achievement in perspective, it represents a staggering 47 per cent increase over the national output value recorded just five years ago. Notable contributions over the year came from gold which increased production to 10.2 tonnes (up nine per cent), ironsand production at 2.3 Mt (a 20 per cent increase), and industrial rocks and building stones (up six per cent) with rock for building, cement and roading showing significant rises on the back of strong regional growth and infrastructure development. Many regions, in particular Auckland, Bay of Plenty, Wellington and Southland, recorded significant increased regional activity with supply often struggling to meet demand. By contrast the coal sector had a relatively steady year with production remaining stable at just over five million tonnes for the second year running. Coal exports however are now consistently exceeding two million tonnes annually, generating export earnings of over $200 million, and could well be higher with rail capacity improvements. Many countries throughout the world are now importing our high quality bituminous coal for steel manufacturing and other industrial uses.

Jan 1, 2005

IN the western mines, the boss, engineer, geologist, or nipper in making rounds have a password which usually guarantees safe entrance to a working place from below the working miner. Most men won't climb a raise or enter a stope from below where a miner is working until they have shouted "nothin' down" and heard those words shouted back by the miners above. "Nothin' down" is a safety pledge as necessary and as binding as the truce flag to the soldier. It implies mutual confidence that work will be suspended until the person below has come abreast of the workers; and also confidence that the miner who replies "nothin' down" is reasonably sure the place is safe to enter. Like truce flags which are not infallible, so is this password subject to human errors or unexpected falls of rock, tools, or timber. Everyone knows these unavoidable hazards, but what is important to the exposed man is that in that precise moment of time when he has heard the reassurance of "nothin' down," he knows that safety is uppermost in the minds of the men above him. With such assurance we would go anywhere and so would most mining men. If that period of safety consciousness, procured by the utterance of two words, could be multiplied to equal the hours in the working day, there would not be any accidents but those by "the act of God." It is the aim of every safety program to make safety as natural as breathing. That is the reason for the posters, the conferences, instruction periods, safety engineers, and the inspections. But none of these are as effective as one accident, which keeps men on their toes for weeks to come. This is not the price we want to pay for safety consciousness. This Annual Review number of Mining Engineering is full of talk about production. Production for defense, production for profit. In this tremendous surge of industrial might . to make this nation and our very families safe S from the predatory forces abroad in the world today; let us not lose sight of the fact that the . safety of our manpower is more precious than any commodity. Production without safety is detrimental to the national interest, to that of the company, and to the individual. If the words "nothin' down" can give us the best human guarantee of safety, for however brief a time, let us adopt them at least in principle as our slogan in 1952. Production for preservation in '52 - but NOTHIN' DOWN!

Jan 1, 1952

The US Bureau of Mines' dictionary of mining terms defines productivity as "the efficiency with which economic resources (men, material, and machines) are employed to produce goods and services." Or, the relationship between the physical outputs and the physical inputs used to produce those outputs. As demand for mine materials dropped, mining companies and equipment manufacturers discovered that ratios between the inputs and the final products were disproportionate to the profits realized. Some companies are fighting for survival. The US, while still the most productive country in the world in absolute terms, is looking over its shoulder as other industrialized nations continue to exceed its yearly productive growth rate. According to John Belcher, Jr., of the American Productivity Center in Houston, TX, the US has seen a steady decrease in productivity growth since the mid-1960s. During the post World War II period, the US labor productivity growth rate was 3.2% annually. The slowdown began in 1965 and by the mid-1970s, the country's annual growth rate was 1%. By 1978, labor productivity growth ceased to gain at all and from 1978 to 1980 a 2% decline occurred. Solutions to the productivity decrease are increasing product prices or improving productivity. By increasing prices, though, the producer runs the risk of pricing himself out of the competitive market. To maintain an acceptable profit level, prices must increase proportionately higher than required to offset production cost increases, Belcher says. Many companies are turning to in-house productivity improvement programs as an answer to increased costs and declining profits. These programs are geared toward management commitment and employee awareness of what productivity means. Companies are finding ways of measuring productivity levels in financial reporting, budgeting, and planning. Organizational teams have been formed to coordinate activities and oversee product management, and improve productivity of materials and capital investments. This special issue of Mining Engineering examines productivity in the mining industry. First, there are articles about various, and different, factors that affect productivity in each of ME's five main readership areas - exploration, mining, processing, coal, and industrial minerals. There is also a look at mining industry productivity from the manufacturer's view. The next section of this special issue is devoted to some topics that affect all areas and sectors of mining: research, management practices, computers, maintenance, and energy management. Then follows case studies in exploration, coal, and iron and steel. These studies provide examples of practices and strategies used by companies and operations to boost productivity.

Jan 11, 1983

Dr C. M. van Staden (Fellow): Mr President, ladies and gentlemen, thank you very much for this opportunity to contribute to the paper by Dr Stander, and Messrs Henzen and Funke. First of all, my congratulations to Dr Stander on being re-elected President of the International Association of Water Pollution Research. We in South Africa are proud that this honour was again bestowed on our leading scientist in the field of water research. Furthermore, my congratulations to the authors of this paper. The growth of the pollution problem caused by acidic water discharged from abandoned collieries, is known to most of us. However, I am not aware of any case where an abandoned gold mine is directly discharging polluted underground water. I think it is also a debatable point as to what the quality of underground water being discharged from abandoned gold mines would be in the long run. Any reduction works on a gold mine which practises only fairly good housekeeping, should not cause any water pollution by cyanide. First of all, any cyanide solution before gold precipitation would be too valuable to lose. Secondly, the precipitated solution, which contains the cyanide, is used to pump slime to slimes dams. Any cyanide pollution that may occur at the slimes dam, must come from the top and, fortunately, the days when pen stock water was discharged directly from the top of dams into public streams, have gone. Run-off and seepage is usually acidic, thus decomposing the cyanide. The code of practice by the Chamber of Mines is quite clear on the point as to how the tops of dams should be secured, to prevent any process water or storm-water polluting public streams. The general standards are given on page three of the paper. To my knowledge, under certain circumstances a degree of relaxation can be given regarding the faecal coli count; namely a permissible count of 1 000 per 100 ml. I feel very strongly that research aimed at inhibiting the activity of acid-producing bacteria should be encouraged. Success in this field would be of great benefit to the mining industry. I am very thankful that the authors have mentioned vegetation of dumps as a method to combat water pollution, with the full awareness that the key objective in vegetating dumps is to prevent air pollution. A problem that I have not heard mentioned before and on which I would appreciate the views of the authors, is the pollution that may be caused by power-stations discharging

By C. H. Mathewson, M. R. Pickus

The study of the plastic deformation and recrystallization of metals has been the subject of many investigations. In regard to the simple deformational processes, such as tension and compression, the early knowledge gained from studies of polycrystalline material has been supplemented by many significant researches on the behavior of single crystals. Unfortunately, this has not been true for more complicated deformational processes. As far back as 1927, G. I. Taylor1 wrote: It is impossible in the present state of knowledge to do more than give a possible reason why (face-centered cubic) crystals set themselves with a (110) direction in the plane of rolling, and at right angles to the direction of rolling. The explanation of why the orientation of the crystal axes round the transverse direction is what it is, must be left till the distortion of metals, and particularly single crystals of metals in the process of rolling, has been studied in greater detail. That this gap in the systematic study of deformation and recrystallization has not yet been filled was indicated by C. H. Samans, who wrote in 1934 that "only four investigations upon cold-rolled single crystals of any of the face-centered cubic metals have been reported in the literature." Of these four studies, only those of S. Tanaka3 and T. Sakaoj4 both of whom worked with aluminum crystals, had quantitative significance. The other two, carried out by F. Wever5 and W. G. Burgers16 were of a qualitative nature. It is our hope that the present investigation may contribute something to the knowledge necessary for a rationalization of the origin of rolling textures in terms of the known behavior of single crystals, and may add pertinent information concerning the recrystallization characteristics of deformed single crystals.

Jan 1, 1939

By S Miller, A Neale

As part of a long-term acid rock drainage (ARD) mitigation study, PT Freeport Indonesia has completed the construction of a highly instrumented, full-scale, experimental, overburden stockpile to further evaluate the behaviour of the waste rock system at Grasberg mine. A total of 24 lysimeters, 30 sets of thermistor strings and 48 oxygen-sampling ports were installed at select locations during stockpile construction. ARD flow rates and chemistry have been recorded since the start of overburden rock placement in April 2000. Measurements of in situ temperatures and oxygen concentrations quantify reaction rates and the oxygen pathways that control oxidation kinetics deep within the waste rock profile. Direct field observations show the significance of advective oxygen flow with respect to the onset of oxidation kinetics. Oxygen measurements show that the rubble zone that forms at the base of a waste rock bench provides a critical pathway for oxygen entry to the waste rock profile. Furthermore, rapid oxidation as evidenced by measured temperature increases deep within the panels of waste rock is observed to occur. The observations presented in this paper provide critical insight for understanding the mechanisms and behaviour of full-scale waste rock stockpiles with respect to ARD generation. The results of this program will assist in the future selection, testing and evaluation of appropriate mitigation measures with respect to surface and face treatments to reduce long-term ARD generation. This project is a work in progress, and at least another two-years will be required to fully understand site-specific ARD generation and ARD mitigation mechanisms. This paper will discuss various design and construction considerations, provide an overview of results achieved to date, and some preliminary interpretation of what is happening within the overburden stockpiles.

Jan 1, 2003

By M. R. Pickus, C. H. Mathewson

The study of the plastic deformation and recrystallization of metals has been the subject of many investigations. In regard to the simple deformational processes, such as tension and compression, the early knowledge gained from studies of polycrystalline material has been supplemented by many significant researches on the behavior of single crystals. Unfortunately, this has not been true for more complicated deformational processes. As far back as 1927, G. I. Taylor1 wrote: It is impossible in the present state of knowledge to do more than give a possible reason why (face-centered cubic) crystals set themselves with a (110) direction in the plane of rolling, and at right angles to the direction of rolling. The explanation of why the orientation of the crystal axes round the transverse direction is what it is, must be left till the distortion of metals, and particularly single crystals of metals in the process of rolling, has been studied in greater detail. That this gap in the systematic study of deformation and recrystallization has not yet been filled was indicated by C. H. Samans, who wrote in 1934 that "only four investigations upon cold-rolled single crystals of any of the face-centered cubic metals have been reported in the literature." Of these four studies, only those of S. Tanaka3 and T. Sakaoj4 both of whom worked with aluminum crystals, had quantitative significance. The other two, carried out by F. Wever5 and W. G. Burgers16 were of a qualitative nature. It is our hope that the present investigation may contribute something to the knowledge necessary for a rationalization of the origin of rolling textures in terms of the known behavior of single crystals, and may add pertinent information concerning the recrystallization characteristics of deformed single crystals.

Jan 1, 1939