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By Rainer Kahrger, Guenter Ewald

The topic of this paper is to demonstrate the development of mobile crushing installations from throughput capacities of 200 tons per hour, to mobile and semi-mobile large- scale crushing installations with throughput capacities of 3,500 up to 10,000 tons per hour. Basis are approximately 140 mobile and semi-mobile crushing installations which have been built since 1956 or were on order in 1987. [FIGURE 1. Total Number of Mobile or Semi-mobile Crushing Plants] Sixteen of these approximate 140 mobile and semi-mobile crushing installations have a throughput higher than 3,500 metric tons per hour. Mobile crushers were developed more than 25 years ago in Europe for the quarry industry, which had special requirements - fairly low capacity, mostly softer and less abrasive material (limestone) and full mobility. So the majority of the units up to about 1980 were fully mobile, having a fairly small capacity and utilizing mainly hammermills, double roll and impact crushers. It was only when the mining industry and large quarries picked up the concept in the early 1980's that a drastic increase in capacity took place. Even though the first mobile crusher in a true mining application went into service in 1971, it took another 10 years before it proceeded in a larger scale. This trend was obviously supported by the drastic fuel price and energy cost increase in the mid 70's. Since the cost of conveying material is substantially cheaper than trucking it, the increase in energy cost, combined with increasing haulage distances provided a strong incentive. Figure 1 shows clearly the throughput distribution of all crushing installations and it also shows the sharp increase in the throughput capacities within the last few years.

Jan 1, 1989

By Kadri Dagdelen, Thys B. Johnson, Salih Ramazan

Long-term production scheduling design is a very important part of mining because it determines the economic outcome of a project There have been many attempts to solve the optimum pit scheduling problem, but there has been no success in developing a scheduling method to give optimum results in maximizing net present value of a mining project. Open pit production scheduling problem can be formulated as a mathematical programming problem and solved using Mixed Integer Programming technique. However, it is not possible to solve the formulation within a reasonable time since the number of integer variables required for the mathematical model is too great to do that by today's available computer technology. There- fore, a methodology is required to combine, or aggregate, the mining blocks and to decrease the number of integer variables in scheduling without losing the optimality. Therefore, the fundamental tree concept was developed in this paper to combine the blocks. A fundamental tree is defined as any combination of blocks such that: 1. the blocks can be profitably mined, 2. the blocks obey the slope constraints and, 3. there is no subset of the chosen blocks that meets 1 and 2. A Linear Programming (LP) formulation is developed as a mathematical model to find a set of fundamental trees that exist for a deposit. Since the blocks are combined to form the fundamental trees, the number of variables required for the scheduling model is decreased significantly. This decrease in the number of variables makes it possible to mathematically formulate the multi-time period scheduling problem as a Mixed Integer Programming (MIP) model. A case study is performed on a multi-mineral copper deposit in Peru, South America. NPVs of annual after-tax cash flows generated based on the schedule provided by the "Fundamental Tree Algorithm" is compared with NPVs resulted from the schedules coming from three of the computer packages presently available to the mining industry. These are Mintec's M821V, Earth- work's NPV Scheduler, and Whittle's Milava open pit mine schedulers.

Jan 1, 2002

By John D. Katsllometes

In the mining and processing industry, the maintenance plan has often evolved rather than being consciously set up resulting in an overreliance on breakdown and fixed-time maintenance (planned maintenance). Historically mining and processing plant equipment has been robust and less automated than modem equipment, making it relatively easy to work on. Mining and processing plants have relied on large and expensive maintenance departments to enable rapid attention to breakdowns. Maintenance itself can result in excessive downtime and costs. This results from the requirement to take the machinery off-line to carry out (possibly unnecessary and invasive) maintenance. The danger of infant mortality after it has been put back on line again and also the cost of the maintenance action itself contributes to costs. A goal of any well-run maintenance program is to have the lowest cost while providing 100% capacity 100% of the time to operations. When maintenance investments are at a minimum, the cost of lost production is at its highest. As maintenance effort and investments are intelligently increased, the production loss gradually decreases until the lowest combined cost is achieved. This is the maintenance goal. A road map is needed to achieving maintenance excellence. This article addresses a "Road Map" to achieving maintenance excellence. INTRODUCTION Mining and processing industry maintenance is big business. A world-class maintenance program is characterized by maintenance excellence.

Jan 1, 2004

By C. E. Agnew

The Eastern district, composed of New Jersey and eastern Pennsylvania, with its native ores, was the cradle of the iron industry of the United States. The district attained and held the leadership in production of pig iron for over 100 years, from pre-Revolutionary days to approximately 1875. The first shipment of Lake hematite ore was made in 1853. It was a small shipment, transported by a sailing vessel and a canal barge, but it was the beginning of the end of the supremacy of the Eastern district, although at that time the ore was supposed to be too rich to be successfully smelted with the block coal then in use at western furnaces. The iron made from the first shipment of Lake ore was worked into nails by the Sharon Iron Co., at Sharon, Pa. The writer's great-grandfather, David Agnew, and his brother, John P. Agnew, owners and operators of the Sharpsville furnace, Sharpsville, Pa., worked the shipment through a furnace. Because of this, the writer feels some satisfaction in having been one of a group that solved the problem of making profitable an operation using Eastern district ores exclusively. With the development of Lake mines, and the production and use of coke, the Middle West district gradually assumed the position of leadership in production; because, even though the ores were transported 1000 miles by water and rail, its cost figure on pig iron was better than that of the eastern producer whose furnace was next to his mine. Such a cost figure was possible because the ore was naturally rich in iron and reduced easily. It was possible to carry a heavy burden on the furnace, which resulted in large tonnage and low coke per ton of iron. This paper is in no sense a technical one. The purpose is to show that with the proper physical preparation of the Eastern magnetites they will reduce as easily as the Lake hematites, and because of the high iron concentration give the Eastern producer just as much advantage as formerly he was at a disadvantage in comparison with the Middle West producer.

Jan 1, 1938

By F. T. Cawood

This paper reviews the Mineral and Petroleum Resources Royalty Bill of 2006, identifies potential areas that require further consideration by the National Treasury and, where appropriate, offers alternatives. At its basic level a royalty regime consists of two elements: the base and the rate that must be applied to the base. Deciding on an acceptable royalty rate is a complex matter and can be done only after extensive analysis of all variables affecting the competitiveness of the regime. The proposed royalty rates are in the range of zero to five per cent and are based on sales revenue. It is argued that future investment patterns are more likely to be influenced by market cycles and commodity prices than policy events. Inevitably the current boom in the minerals sector will come to an end and the success of the proposed regime will be known only when profit margins are under pressure. Policy makers must therefore have the long run in mind when developing policies that affect the ability of industry to do business, without the need to renegotiate each time there is a change in the market. A long-run policy must be sufficiently flexible to allow for consistently fair sharing ratios and splitting of revenues between government and industry. Although broadly in line with international practice, the current version cannot be regarded as internationally competitive and efficient. In order for the royalty bill to become internationally competitive, promote beneficiation of mineral production and adequately compensate the State for the loss of a national resource, the National Treasury should heed the following main recommendations in this review: 1. Abandon the notion that each mineral product must have its own royalty rate; 2. Introduce an NSR type royalty that allows for value-addition costs to be deducted from the base; and 3. Provide for automatic relief through the use of a sliding-scale mechanism based on ability to pay, e.g. the X-Factor used in the gold mining tax formula.

Jan 1, 2007

By Strathmore R. B. Cooke, William F. Stowasser

RESULTS presented in a previous paper1 have shown that the strength of fired pellets made from eastern Mesabi magnetite concentrates containing 8 to 9 pct Si02 as quartz and silicates is due to several processes which occur during firing. These are: l-recrystallization and cementation of the fragmented magnetite grains; 2-formation of slag from reaction between the quartz, silicates, and available ferrous iron, followed by slag-bonding of the magnetite grains; and 3-oxidation of the magnetite to hematite and subsequent recrystallization and grain growth of this constituent. Microscopic examination of all magnetite pellets fired in one operation in small and large-scale pilot plant furnaces and possessing normal strengths shows that the processes 1,2, and 3 have taken place; where strengths are low and the pellets are otherwise sub- normal, one or more of the processes has not occurred. For example, soft and friable red pellets may contain a central core of slag-bonded recrystallized magnetite which is strong enough in itself, but the shell contains only slightly recrystallized hematite, indicating that the maximum temperature reached was too low. Processes 1 and 2 can occur only under reducing conditions, as for example, when coal is intention- ally added to the original pellets; under neutral conditions, when pellets are fired in an inert atmosphere; or when pellets are brought so rapidly to temperature in an oxidizing atmosphere that oxygen diffusion to the core lags behind the recrystallization and slagging effects. This last-mentioned process has occurred in all pilot-plant shaft fur-

Jan 1, 1952

IT does not seem practicable to review all the other specialized curricula that have developed in the mineral industries field in so much detail as has been given for petroleum. Nor is it easy to draw a definite line between true curricula, leading to a designated degree in the special subject, and options, which may range from the mere substitution of one or two courses for others in the final years to differences so extensive as almost to amount to separate curricula. Even to attempt to catalogue all the options that have been offered at one time or another would require too much space. The remainder of this discussion, therefore, will be confined to three topics which seem to be of major importance. Mining and metallurgical curricula will be covered in a later chapter. GEOLOGY The first, from the historical view, is geology in its relation to the mineral industries. Previous chapters have made clear that in the early years of mineral industry instruction in the United States economic geology and mining engineering so overlapped one another that men who were by, training and experience economic geologists were appointed professors of mining, while men who had graduated as mining engineers sometimes developed into professors of geology. Even today men whose basic training was in geology as a pure science, and who perhaps took a doctor's degree in that subject, have attained such distinction in the mineral industries as to be universally accepted as "mining men," and their right to be regarded as mining engineers would- not be questioned, even though they did not take a degree in engineering. Nevertheless the distinction does exist, and has been made a concrete reality in recent years by the enactment of

Jan 1, 1941

By J. E. Zeilinger

This Bureau of Mines report describes the preparation characteristics of three samples collected from the Kidney seam, in the Northern Field of the anthracite region. Removal of the sink 1.70 specific gravity material from the samples collected would result in greatly reduced ash contents at yields in excess of 90 percent. The Kidney seam, in the locations sampled, proved to be a low-ash anthracite containing an unusually high percentage of float 1.45 specific gravity material.

Jan 1, 1970

?Introduction to the Delphi Group ?Why is carbon important to your organization ?Key elements of a carbon management strategy ?Inventory ?Risk & opportunity scan ?Mitigation options and financial mechanisms ?Identify targets and develop policy ?Communication and improvement ?Manage for success

May 1, 2009

By John Wellington Finch

In August, 1927, the writer examined certain copper deposits in New Mexico1 which occur in beds of sandstones and shale, and in connection therewith reviewed the literature upon deposits of this type. Such deposits are known and have been reported upon at various points in Texas, Oklahoma, Arizona, Colorado, Wyoming and Utah, but in New Mexico they have been given more development than elsewhere and apparently occur there more conspicuously than in the other states. Some 25 years ago the writer examined deposits of similar origin in northern Arizona and more recently other deposits in western and southwestern Colorado, and these examinations have led him to realize how widely scattered are the deposits and how generally noncommercial they are. On superficial development, to one without a comprehension of their geologic nature, they are alluring on account of occasional small amounts of high-grade ore and much misplaced capital has been expended upon them. This paper, therefore, aims to present briefly certain theories of genesis, some details of which may possibly be new, and to lead up to practical conclusions which may be useful to other geologists and engineers. A bibliography of the more important literature upon such deposits is given below.2 Coffin's Bulletin upon the Radium, Uranium and Vanadium Deposits of Colorado, published in 1921, is a particularly clear discussion. The most comprehensive recent statement is Butler's.

Jan 1, 1928

By Sunder S. Saluja

Man had to learn to break rocks as early as the Stone Age, when they formed his main source of raw material. He started with chipping and over the years has reached a stage where he can employ atomic blasts and break, with one blast, millions of tons of rock. In between these two extremes there have been several stages of development including firesetting, use of the expansion of water on freezing in chipped cracks in cold climates, the use of low or deflagrating explosive black powder in about the 17th century, the use of high explosives with the discovery of nitroglycerine in 1846 by Sobrero, followed by the monumental discoveries of the great Swedish scientist Alfred Nobel in the latter half of the nineteenth century. The attempts to develop a stronger and still stronger explosive force were accompanied by investigations to understand the mechanism of failure of rock so that the force could be used to the best advantage; the latter, of course, have lagged far behind the former. This is mainly due to the fact that the chemical reactions involving high explosives as well as the processes resulting in the breakage of rock take place at too great a rate to be studied with the equipment that has been only recently available. Moreover, the development of stronger explosive forces was prompted by military necessities in the past and competition, at present, among highly developed nations. With the development, however, of the new techniques such as micro- second photography, microsecond flash radiography, extremely high-speed movies, strain gage assemblies, electronic chronographs and other improved electronic techniques, the investigator has in the last decade or

Jan 1, 1968

By Robert W. Hyers

Electromagnetic levitation has proven important in a wide range of experiments, all affected by fluid flow. For some experiments such as viscosity measurements, only whether the flow is laminar or turbulent must be established. For other experiments, however, quantitative assessments of velocity, shear stress, or shear strain rate are required. In most cases it is difficult or impossible to measure the internal flow in levitated droplets directly. The samples are usually small, opaque, reactive, high-temperature, metastable, or all of these. Furthermore, recirculating flow limits the utility of tracking surface particles, since they collect in stagnation points ratherthan following the flow. Most research groups have chosen mathematical modeling to assess the internal flow in levitated droplets. A variety of analytical and numerical methods have been applied, including both laminar flow and various turbulence models. A number of these models are reviewed and their impact on different containerless experiments is assessed. Much of the research reviewed here was performed by alumni of Professor Julian Szekely, and by others using similar methods.

Jan 1, 2006

By Robert Linton

In 1898, Joseph L. Giroux and J. A. Snedaker organized the Pilot Knob Copper Co. and began developing the Pilot Knob mine at Kim-berly, Nev., for high-grade copper ores, carrying good gold and silver values, that the formation had disclosed. At that time the nearest railroad was over 150 mi. distant. The high-grade ores did not prove to be extensive at this point—at least to the depth (240 ft.) to which the work was carried—but development of neighboring claims indicated extensive deposits of sulfide porphyry ore of concentrating grade lying at shallow depth, and deeper deposits of direct-smelting oxidized ores occurring in limestone near the limestone-porphyry contact. The properties passed through the hands of several organizations, with only meager development, until acquired in 1913 by Consolidated Coppermines Co., whose holdings now comprise 3480 acres of mining claims in the Robinson district. Since that time development has been prosecuted more actively; and for the purpose of determining the most efficient and economical method of treating the ores, considerable testing work has been done during the past three years, both in the laboratory and in actual mill operations. At first, the shipments were of ore high enough in grade to be profitable even with the long wagon hauls to the railroad and prevailing freight and smelting charges. In 1905, a blast furnace and a concentrator were erected at Kimberly. On account of insufficient ore supply, the blast furnace was never blown in and later was dismantled. The concentrator as originally equipped was operated for only about two months, both because the ore supply at that time was not sufficient and because gravity concentration did not yield satisfactory extraction. The location and arrangement of the mill further entailed high operating costs. In 1908, the Nevada Consolidated Copper Co. began to mill successfully, on a large scale, its sulfide porphyry ores, which are similar in character to the adjacent Coppermines ores. After that time, all of the ores and concentrates produced by Coppermines Company were smelted and a considerable part of the Coppermines low-grade ores concentrated at the Steptoe works of the Nevada Consolidated Co.

Jan 1, 1921

By Charles Pack

Extensive progress has been made in the metallurgy of alloys for die castings. Enthusiastic proponents of some alloys are inclined to make extravagant claims for their materials, which may be justified by physical tests on test bars made from the respective alloys but are seldom justified by the results obtained with commercial die castings made from those alloys. Chemical analysis of the test bars and castings fails to determine the cause of these variations, since they are due to other physical factors entering into the commercial production of die castings. In this paper, an attempt will be made to outline some of the factors in commercial die-casting practice to which these variable results may be attributed, in the hope that the manufacturer of die castings, recognizing the importance of these factors, will devote more attention to them in the design and construction of dies and equipment. In 1914,l the author defined die castings as "metal castings made by forcing molten metal, under pressure, into metallic molds or dies." This definition was given in order to differentiate die castings from other molded metal products such as "permanent-mold" castings, L'slush" castings and similar products that are sometimes erroneously termed die castings. The term "die casting" could be interpreted to include all castings made in metal molds or dies; but since this term, like most of our technical nomenclature, has been developed by commercial practice we must look to this practice for its proper definition. The Germans, with their usual devotion to desecriptive names, have adopted the name of sprilzguss (squirt cast) for die castings. Undoubtedly this name is more descriptive of the die-casting process, where the metal is literally squirted into the die and serves to differentiate this process from other metal mold processes, where the metal is poured into the die. In the earlier paper mentioned, the author also emphasized the fact that the definition given for die castings indicated clearly that the satisfactory operation of the process must comprise three factors, all of which must be considered of vital importance to the successful operation of the die-casting process:

Jan 1, 1931

By Griffiths J. B

From its mining lease at the northern end of Cohens Reef at Walhalla in the North Gippsland Mountains, the Long Tunnel Extended Gold Mining Company produced 13,695 kg of gold, which at 1980 prices represents a value significantly in excess of $200 million. In the period 1885 to 1908 the mine was one of Australia's principal reef gold producers, being top Victorian producer in six of these twenty-four years. Prior and subsequent occupants of the lease produced an additional 160 kg of gold. The Extended and the other mines on Cohens Reef whilst contributing importantly to the financial resource of Victoria, were the sole important support for the substantial town of Walhalla that had grown up around them. When the mines closed, Walhalla gradually reduced from a bustling developed town to the present attractive mountain village so favoured by tuurriSts. To allow the visitor to obtain a better ;ri.icrstanding of Walhalla's mining past, important parts of the Long Tunnel Extended Gold Mine workings and site are being

Jan 1, 1981

By John Marshall

Silverton was the queen city of the western mining towns in the early 1900s. Located high in the San Juan Mountains, the town constantly grew and changed. Yet, it was subject to the vagaries and whims of economics, politics and disasters, natural or otherwise. Breweries, smelters and sawmills serviced Silverton's swelling mining population, which reached several thousand at its peak. Two trains a day ran from Durango to Silverton, in addition to trains running from Silverton over the top of Red Mountain on to Ironton. They ran up Cement Creek to the little town of Gladstone and up the Animas River Valley to Howardsville, Eureka and Animas Forks. During these prosperous times, construction flourished. There were plenty of wooden structures, and many of these stand today. The first brick buildings were built by bricklayer Patrick Stanley in 1877. It took quite a while for the first car to arrive. Almost 28 years passed from the coming of the first train to the arrival of the first car. It was brought over 3,840-m (12,600-ft) Stony Pass from Creede, CO, in an incredible journey retold years later by Louis Wyman. "Dad's daydreams were not the idle musings or the fantasies of a mystic," Wyman said. "They had a way of erupting into reality. He advocated and built good roads," he said. "During the summer of 1910, he was up to his sweatband in a project that took in half the state of Colorado. He envisioned an automobile highway, unheard of at that time, running southwest from Denver through the scenic grandeur of the high Colorado Rockies. The road would traverse a thousand miles or more of the state's finest recreational land finally circling back to Denver. Years later, when all of the county roads had been connected, it became known as 'Colorado's Thousand-Mile Circle Route.' Of course, Silverton and the San Juans were bright stars along the way."

Jan 1, 1997

CONTENTS PAGE ANDERSON, ROBERT J., and ENOS, GEORGE M.-Corrosion of Brass as Affected by Grain Size. Discussed by Henry S. Rawdon, Robert J. Anderson, Francis B. Coyle, William B. Price, and W. R. Webster 1 RAWDON, HENRYS., and MUTCHLER, WILLARD H.-Effect of Severe Cold Working on Scratch and Brinell Hardness. Discussed by W. H. Bassett, John Livermore Christie, John R. Freeman, Jr., W. R. Webster, William B. Price, Norman B. Pilling, D. J. McAdam, Jr., F. G. Smith, Zay Jeffries, F. E. Carter 3 WILLIAMS, ROBERT S., and HOMERBERG, VICTOR 0.-Relation of Heat Treatment to the Microstructure of 60-40 Brass. Discussed by 0. W. Ellis 14 Corrosion of Brass as Affected by Grain Size Discussion of the paper of ROBERT J. ANDERSON and GEORGE M. ENOS, presented at the New York Meeting, February, 1924, and issued as Paper No. 1282, with MINING AND METALLURGY, December, 1923. HENRY S. RAWDON,* Washington, D. C. (written discussion).-So numerous and so varied are the factors that affect the corrosion of metals that particular care is necessary in corrosion tests to eliminate so far as possible all extraneous factors. It appears to the writer that the question may well be asked as to whether all the necessary precautions have been observed in this investigation. It may be that the points to be mentioned were considered by the authors and found to be insignificant; however, there is nothing in the report to show this.

Jan 5, 1924

By C. D. Young

IN an effort to employ cast steel of a stronger structure than that found in the annealed steel castings, the possibilities of heat treatment which will increase the strength without materially decreasing the ductility may be resorted to. The following abstracted report (which is a brief outline of what has already been clone by the Pennsylvania Railroad Co. at its shops and Test Laboratories at Altoona, Pa.) is of material interest, as it indicates what may be done with steel castings when properly treated, thereby permitting in railway service greater strength of cast steel parts without any increase in weight or space. The question of the heat treatment of alloy steel castings is not taken up in this paper. The obscurity formerly surrounding the heat treatment of steel has been for the most part removed by the development of our knowledge of the critical points of steel, pyrometers, furnace construction, and the testing of the finished product. The operations of the heat treatment proper will be taken up under the heads of (1) heating for quenching; (2) quenching; (3) drawing. (1) Heating for Quenching.-Heating for quenching is best conducted slowly, especially in the case of castings of variable thickness. Cracks may occur either in heating or in cooling, clue to different temperatures at different points of the casting. The castings should be thoroughly soaked at the maximum temperature (generally 1,500° to 1,600° F.), 1 hr. being sufficient for sections 1 ft. in thickness. The minimum temperature which will produce the desired hardening effect will, in all cases, be found to be the most satisfactory, as the grain coarsens when the critical range is exceeded to too great an extent. All temperatures should be governed by a checked pyrometer with the hot junction to the heated object, and with several couples in a large furnace to insure a uniform temperature.

Jan 2, 1914

By T. H. Jones

Fall of ground is a leading source of worker injury and fatality indicating a persistent need for ground monitoring technology. The HRTMM is an experimental convergence monitor utilizing a digital camera and custom software to track the position of one or more lasers across the target. Apparent laser movement is proportional to target convergence. The HRTMM was installed in an underground mine near active operations to test its response to the mining environment. This included intense blasting vibration and mine fog. Results and potential of the new monitoring technology will be discussed.

Jan 1, 2008

By B. B. Zavoico

The oil industry in the Soviet Union closed the 1929-1930 operating year fulfilling its assigned program. During this period of time, however, no basic improvements were noted within the industry. A careful study of the conditions indicates that disorganization in most branches increased continually; that supply and transportation problems are approaching a state of breakdown; that labor problems become increasingly difficult and that the estimates for 1931-1933 period are too large. The production of all Russian fields increased by 27,200,000 bbl., as compared with the 1928-1929 operating year, while the next year's program anticipates a further increase of 46,000,000 bbl., and the 1933 plans call for an amazing total of 330,000,000 bbl., or over 150 per cent, more than the production of the operating year that has just closed. Table 1 shows petroleum production in Russia by individual areas and fields from 1916, and furnishes estimates for the three coming years, which constitute the balance of the Five-year plan. A brief analysis of Table 1 will show that the Soviet Planning Commission anticipates that the fully developed fields of the Apsheron-Baku will double their production by 1933, .as compared with 1929-1930, and that the old Grozny fields, which are already showing a tendency to decline, will increase their output from 44,110,000 bbl. in 1929-1930 to 68,000,000 bbl. in 1933. Furthermore, in 1933 new fields are slated to produce not less than 100,000,000 bbl., a figure which even under most favorable conditions in Russia would be hard to achieve. Of course, Russia could develop such production, because the country is not lacking in the prospective reserves, but the transportation in the country today (as in the past.) is in such poor shape that neither the supply of a gigantic oil industry nor the movement of its products is within the realm of possibility. Table 1 shows the future estimated crude oil production as required by the Five-year plan, and also as reasonably estimated by the author, taking into account natural declines in old fields, slow development of new areas and the deficiency of the transport. While in the 1929-1930 operating year only two major fields underproduced (Surakany and Maikop) and the plan was fulfilled to the extent of 97.4 per cent., the production of the last three months of 1930 ("Shock Quarter") indicated

Jan 1, 1931