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By C. L. Workman-Davies

Noise is a form of pollution arising mainly from the activities of man. One such activity is mining, in which man, as in many of his other activities, uses machinery of various kinds to achieve safe, healthy, and economic production. Trackless mining makes use of an advanced state of technology over that required In traditional mining methods. One of the advantages of the former, as distinct from any disadvantages it may have, is a reduction in noise levels, the number of people exposed to noise, and the duration of their exposure to noise. This paper briefly examines why noise is a problem and what various countries are doing about it in terms of standards, codes of practice, and regulations. It also investigates the extent to which noise is a problem in mining and how trackless mining alleviates this problem. The question is then posed as to whether South Africa is not setting too high a standard at this stage of its national development by comparison with what is being done by other, more-advanced countries.

Jan 1, 1989

By Agustín Arias

El presente artículo describe brevemente la historia, métodos de explotación, mecanización, energía eléctrica, las plantas de preconcentración y flotación y el consumo de reactivos de la compañía minera Milpo.

Nov 1, 1954

The following notes have been compiled to assist authors in the preparation of papers for presentation to the Institute and for publication in the Journal. STANDARDS FOR ACCEPTANCE To merit consideration papers should be of sufficient high standard and contain matter that is new, interpretations that are novel or of new significance and conclusions that cast a fresh light on old ideas. Their publication should be of real interest to technical men and of benefit to mining and industry. Authors must realize that because a mine shaft is new or the mine itself is newly established, this in itself does not justify a paper unless significantly new techniques or processes were involved in the opening-up procedure. A few well selected diagrams and illustrations are often more pertinent than an amorphous mass of less well chosen material. Over-statement and dogmatism are jarring and have no place in technical writing. The amount of textbook material included in a contribution should be the minimum essential to the argument. The length of a paper is not the criterion of its worth and it should be as brief and concise as possible, consistent with the lucid presentation of the subject. Avoid the use of the first person, be objective and do not include irrelevant or extraneous matter. Papers should be submitted at least three months prior to the intended date of presentation. The text should be typewritten, double-spaced, on one side only of foolscap paper, leaving a left-hand margin of 11/2 inches, and should be submitted in duplicate to facilitate the work of the referees and editors. Galley proofs are sent to the authors for the correction of printers' errors and not for the purpose of making alterations and additions which may be expensive. Should an author make alterations which are considered excessive, he may be required to pay for them. ORTHODOX SEQUENCE Title and author's name together with author's degrees, titles and position Summary, abstract or synopsis Introduction Development of the main substance Conclusions References. Title: This should be as brief as possible, yet give a good idea of the subject and character of the paper. Style: Writing should conform to certain prescribed standards. The Institute is guided in its requirements by: Collins, F. H. Authors' & Printers' Dictionary-Oxford University Press. Hart, H. Rules for Compositors and Readers. Humphrey Milford (familiarily known as the Oxford Rules). Fowler, H. W. & F. G. The King's English-Oxford University Press. Generally: Avoid unnecessary use of capitals and hyphens, while punctuation should be used sparingly and be governed by the needs of sense and diction. Sentences should be short, uninvolved and unamiguous. Paragraphs should also be short and serve to separate basic ideas into compact groups. Quotation marks should be of the 'single' type for quotations and "double" for quoted matter within quotations. Interpretations in the text should be marked off by parenthesis ( ), whereas brackets [ ] are employed to enclose explanatory matter in the text. Words to be printed in italics should be underlined singly. For small capitals they are to be underlined DOUBLY and for large capitals TREBLY. Abbreviations and symbols are laid down in British Standard 1991 and proof correction symbols in British Standard 1219c. Abbreviations are the same for the singular and plural, e.g. ft for foot and feet, lb for pound and pounds. Percentages are written in the text as per cent; the symbol % is restricted to tables. Likewise ft and in. should be used, x' y" only being permissible in diagrams and plans. Drawings and diagrams are to be in black India ink and should be about 6 in. wide. Numbering of tables should be in Roman numerals: 1, 11, etc. and figures in Arabic numerals: Fig. 1, Fig. 2, etc. Photographs should be black and white glossy prints. As a guide to the printer the author should indicate by means of notes in the margin of the typescript where drawings and diagrams, etc. are to appear in the text. When submitting graphical representations avoid a fine grid if possible. Curves should be in heavy line to stand out. Lettering too should be bold as a reduction in size is often involved in the printing process. SUMMARY ABSTRACT OR SYNOPSIS It is most important that the summary should provide a clear outline of the contents of the paper, the results obtained and the author's conclusions. It should be written concisely and in normal rather than abbreviated English and should not exceed 250 words. While the emphasis is on brevity this should not be laboured to the extent of leaving out important matter or impairing intelligibility. Summaries simplify the task of abstractors and therefore should present a balanced and complete picture. It is preferable to use standard rather than proprietary terms. FOOTNOTES AND REFERENCES Footnotes should be resorted to only when they are indispensable. In the typescript they should appear immediately below the line to which they refer and not at the foot of the page. References should be indicated by super-script, thus . . .1 . . . 2. Do not use the word Bibliography. When authors cite publications of other societies or technical and trade journals, titles should be abbreviated in accordance with the standards adopted by this Journal.

By Oliver Bowles

Sandstone, a widely distributed siliceous sedimentary rock, is the third most popular building stone in the United States. It is formed by the breaking down of preexisting rocks by weathering, subsequent segregation of the detrital quartz grains into discrete deposits by the sorting action of water or wind, and finally cementation of the quartz sand into a coherent rock. The homogeneity and resistance to weathering of the resultant sandstone make it suitable for exterior construction. Its excellent wearing properties explain its popularity for flagging and stair treads. However, quarrying and dressing methods and costs are adversely affected by the abrasiveness and hardness of sandstone especially as compared to limestone.

Jan 1, 1963

In Munich's peculiar hydrogeological conditions (water bearing sand strata between layers of impermeable clay, silt or marl) are proper functioning groundwater lowering methods of decisive importance for underground construc- tion. Shield tunnelling with compressed air has al- ready proved to be successful. In view of growing application of shotcrete tunnelling it was obvious to consider the use of compressed air even here. After a preliminary research-project the first subway section "shotcrete under compressed air" was 1979 awarded in Munich and since that time five sections have been awarded, respectively completed. On the basis of the experiences meanwhile obtained reports will be given stating the frame conditions in which this new construction method can be applied. The tunnels consist of two shells. The outer ist driven by shotcrete under compressed air. In order to keep the air overpressure low, the groundwater often is previously detensioned or partially lowered. The inner shell of watertight concrete is built under atmosperic pressure.

Jan 1, 1987

By John W. Stevenson

At Jim Walter Resources Alabama coal property, the first of twelve projected longwall mining systems started to operate In March, 1979, at the No. 3 Mine. The second longwall started to mine adjacent to the original workings in June, 1980. At the end of 1980, 2 ½ panels had been extracted using the same basic ventilation plan. A single split of air ventilates each longwall panel with intake air traveling the headgate across the face to the tailgate where it is directed and controlled to a 1500 foot deep fan shaft specifically located to exhaust from the longwall area and the gobs associated with longwall extraction. The simplicity of the system makes it easy to understand, apply and control In a relatively gassy coal bed.

Jan 1, 1981

By Mark R. Svinkin

Construction-induced vibrations may be detrimental to adjacent structures and sensitive electronics operating nearby. Construction vibration sources have a wide range of energy and velocity, as a function of time, transmitted on the ground. Analysis of existing methods for predicting ground and structure vibrations shows that empirical equations provide calculations only of amplitudes of vertical soil vibrations with insufficient accuracy. This paper presents the application of the impulse response function concept to solve the geotechnical problem of predicting ground and structure vibrations before installation of vibration sources. Impulse response functions reflect real behavior of soil and structures without the investigation of soil and structure properties. A procedure is presented to compute predicted ground and structure vibrations. Good agreement is found between predicted and measured records.

Jan 1, 1999

By S. Konetschnik, Lux Degel, R. Degel, T. Haslinger

UrbanGold and its partners from Mettop and SMS group have developed a novel technology for the recovery of valuables from all non-ferrous metals’ fractions of WEEE (Waste Electrical and Electronic Equipment), with a special focus on low qualities which are commonly landfilled or incinerated. The technology is marketed under the brand name “UrbanGold Flex” to illustrate the high flexibility in respect of plant design and raw material portfolio, allowing also the processing of low grade material and materials with high caloric values. The process of the technology’s centrepiece, a modified and enhanced bath smelting furnace called “HENRI”, was investigated in numerous pyrometallurgical trials as basis for a scale-up towards a capacity of up to 100,000 tons of WEEE-concentrates per year. All relevant facility components have been evaluated in respect of references, fall-back options, as well as exit strategies (alternatives) to minimize risks when establishing a novel technology. A spin-off within the development is the “UrbanGold Compact” technology which can be seen as optimization of state-of-the-art smelters by using an optimized TBRC as primary processing unit. As an UrbanGold Compact plant will be the first industrial scale reference of UrbanGold’s technologies, it is also explained in the publication. As precious metals recovery is of major (economical) importance when recycling WEEE, major attention has been given to minimize the losses of these valuables. These measures, as well as a sophisticated way of utilizing waste heat as far as possible, result in interesting business cases with gross profits of up to 20% or even more. INTRODUCTION Over the past years, the demand of electrical and electronic equipment has increased dramatically with technological progress. Innovations on the technology of electronic devices led to a shorter usage and lifespan and thus boosted the generation of Waste Electrical and Electronic Equipment (WEEE). WEEE is one of the fastest growing waste streams, growing at 3 to 4% per year worldwide and is expected to reach more than 52 million tons per year by 2021. Currently, about 45 Mt of these wastes are estimated to arise worldwide, and the trend is rising (Baldé et al., 2017).

Jan 1, 2019

By J. Hu, F. Lin, R. Chen, F Peng, S. Yang, W. Yu

"Microseismic monitoring technology has become one of the most effective method of mine ground pressure monitoring after decades of development. But safety assessment of mine ground pressure by using microseismic monitoring is still in the development stage, it needs to be perfected continuously in practice, and choose the optimal assessment indexes and methods. The definitions and physical meanings of wave velocity, b value, and EI-VA value are introduced in this paper. Statistical calculation of the microseismic events in Luomu Mine is finished by using these indexes, then the functions and calculation results of V, b value, and EI-VA value with the variable of time are also given in the paper. The preliminary safety assessment method is established in Luomu Mine, and it has achieved good results in practical application.1.1 Engineering background The Luomu Mine is a super large molybdenum and tungsten production base in China, ore reserves is up to 2 billion tons, first in Asia and third in the world. It begins mining since the 1960. and bases on underground mining until 2002. In order to recover resources more effectively, it began to use opencast mining method and formed a production of 30000t/d in the early 1990. After about 30 years of underground mining, a large mined out spaces was formed under open pit mine, up to area of 1.2 million m2 and volume of 18 million m3, as shown in figure 1. The large number of mined out spaces seriously affects the normal production, mining and handling of mined out spaces are in the high risk. In the past years, several rock mass collapsions happened, and it caused a serious security threat to persons and equipments. According to the distribution characteristics of mined out spaces, Luomu Mine is divided into A, B, C, D and E mining area. The stability of D mining area is studied in this article. D mining area mainly includes 1376,1350,1340,1317 mined out spaces and 1280 deep large mined out area, as shown in figure 2. The mined out spaces of D mining area is extremely complex and high-risk. Therefore, a microseismic monitoring system was built to monitor the stability of D mining area, a large number of valuable datum has been obtained, and it has a striking effect (Cheng & Peng, 2013; Peng et al., 2013)."

Jan 1, 2015

The following officers and committee chairmen were elected: Honorary Chairman, Herbert Hoover; Chairman, Elmer A. Sperry, New York; Vice-Chairman and Chair-man of the Executive Committee, John W. Lieb, New York; Vice-Chairman, C. E. Grunsky (Pacific Coast), San Francisco; C. F. Kettering (Middle West), Detroit; Execu-tive Secretary, Maurice Holland; Executive Committee: Gano Dunn, George W. Fuller, Maurice Holland, Frank B. Jewett, John W. Lieb, H. J. McGraw, Calvin W. Rice, W. E. Wickenden, all of New York; Dugald C. Jackson, Cambridge, Mass.; 0. C. Merrill, Washington, D. C.; Charles F. Scott, New Haven, Conn.; Elmer A. Sperry, Brooklyn, N. Y.; Finance Committee. John W. Lieb; Technical Program Committee: D. C. Jackson; Transporta-tion Committee: F. B. Jewett; Entertainment Committee: 0. C. Merrill; Publicity: J. H. McGraw; Promotion and Attendance: George W. Fuller.

Jan 5, 1928

1876, PROF. RICHARD AKERMAN Stockholm, Sweden. 1913. DR. FRANK DAWSON ADAMS Montreal, Canada. 1909. PROP. RICHARD BECK Freiberg, Germany. 1905. ANDREW CARNEGIE New York, N. Y. 1906. DR. JAMES DOUGLAS New York, N. Y. 1888. PROF. HATON DE LA GOUPILLIERE Paris, France. 1966. SIR ROBERT A. HADFIELD London, England. 1888. PROF. HANS HOEFER Leoben, Austria. 1917. HERBERT C. HOOVER San Francisco, Cal. 1915.. JAMES FURMAN KEMP NEW York, N. Y. 1905. PROF. HENRI LOUIS LE CHATELIER Paris, France. 1913. EZEQUIEL ORDONEZ Mexico City, Mexico. 1909. ALEXANDRE POURCEL Paris, France. 1911. DR. ROSSITER W. RAYMOND New York, N. Y. 1911. PROF. ROBERT H. RICHARDS Boston, Mass. 1909. DR. ING. H. C. EMIL SCHROEDTER Dusseldorf, Germany., 1906. JOHN E. STEAD Middlesbrough, England. 1902. PROF. DIMITRY CONSTANTIN TSCHERNOFF Petrograd, Russia. 1910. PROF. TSUNASHIRO WADA Tokyo, Japan. 1907. CHARLES D. WALCOTT Washington, D. C.

Jan 1, 1917

By R. S. Dean

THE numerous theories of hardening which have been advanced in recent years are all satisfactory in accounting for some of the phenomena observed in hardening metals, but none so far presented account for all of the facts observed. Some years ago one of the authors, R. S. Dean,1 presented a theory to account for some of the properties accompanying work hardening. The present paper develops this theory further in the light of recent experimental, work and extends it to other forms of hardening. Many of the ideas included have come from the writings and personally communicated thoughts of others. We have attempted to give proper credit in every case, but it is possible that we have not always done so. As an historical basis it is desirable here to review very briefly the hardening theories which have been current. The first comprehensive theory of work-hardening phenomena was due to Sir George Beilby.2 He contributed the idea that with cold work part of the structure of the metal was rendered amorphous and that it was to this amorphous material that the cold-worked metal owed its difference in properties. According to Beilby's theory this amorphous material was a super-cooled liquid and, therefore, had the characteristics of a vitreous material. That such a theory is not capable of explaining the property changes in metals has been repeatedly pointed out. This theory also allowed a slip to take place only once on a given plane, which, as has been pointed out by Jeffries and Archer,3 is not consistent with the observed length of an individual slip and the amount of elongation which can be obtained by wire drawing. The modifications, which have been proposed to this hypothesis to make it coincide with the experimental facts, have to a considerable extent robbed the theory of its clean-cut characteristics. The commonest of these modifications replaces the amorphous phase with an

Jan 1, 1927

By R. I. Jaffee, J. W. Roberts, D. N. Williams

DISPERSION hardening as an alloying process has aroused increasing interest in the past few years. This alloying procedure, in which an insoluble phase is dispersed randomly through a metal or alloy, is believed to be especially suited for the attainment of creep strength at elevated temperatures since the dispersed phase is metallurgically stable. Another advantage is that the physical properties of the matrix phase, such as electrical conductivity, remain relatively unaffected by alloying. These two characteristics resulted in interest in the applicability of dispersion hardening to copper and copper alloys. A study of copper alloys prepared by powder metallurgy methods has shown some strengthening from oxide dispersions.' However, powder metallurgy processing would not be economical for large scale production of dispersion hardened copper-base alloys. Therefore, the research described in this article was initiated to examine methods of forming dispersion alloys which would not require powder metallurgy processing. If powder metallurgy processing is to be avoided, a method must be found by which the dispersion material can be introduced into and dispersed through the melt before casting. When the dispersed phase is an oxide or similar nonmetallic, it is extremely difficult to form a satisfactory liquid: solid dispersion since successful mixing requires that the melt wet the dispersed phase. It is almost impossible to force a nonwetted particle beneath the melt surface. This difficulty can be avoided, however, if the oxide particles are produced in molten copper by reaction within the melt. The problem would then reduce to maintaining randomness until solidification. Four procedures were considered for producing an oxide particle within molten copper by reaction. In all cases, the intent was to react oxygen (0) with a reactive metal (X) to form an oxide (XO) within the copper melt. These reactions were as follows: 1) (Cu-X), + (O)g (Cu)1 + (XO)S [1] 2) (Cu-X)1 + (Cu2O)s (Cu)x + (XO)S [2] 3) (Cu-OK)1 + (Cu-X)1 (Cu)1+(XO)9 [3] 4) (Cu-OK)1 +(X)s (Cu)1 +(XO)s [4] The reactions were carried out in an 8-lb melt of 99.98 pct Cu maintained in the vicinity of 2200oF by induction heating. Where possible the amount of the reactants was controlled to give 1 to 5 vol pct oxide. Mechanical stirring during the reaction period was used to minimize agglomeration of the reaction product. The presence of a reaction product was determined metallographically by study of an ingot cast from the melt at the end of the reaction period. Reaction [I] was studied by dissolving aluminum in the melt followed by forcing oxygen through the melt. The melts became quite sluggish during the reaction period suggesting that A12O3 was formed. However, the reaction product rose out of the melt rapidly, possibly due to the flushing action of the oxygen stream, and little dispersed phase was formed. Reaction [2] was examined by dissolving aluminum, silicon, or nickel i; the melt and then adding Cu20 (melting point 2250F). This procedure was unsuccessful. Although Cu2O was easily stirred into cop-

Jan 1, 1961

By Michael S. Contratto, Dave Marshall, Tom Brodersen

The European Union (EU) completed a new directive 2002/44/EC1 called the Physical Agents Directive (PAD) that establishes action and limit values for hand-arm and whole body vibrations. The directive specifies that: “…workers shall not be exposed above the exposure ‘limit value’.” 1 and “…once the exposure action values … are exceeded, the employer shall establish and implement a programme of technical and/or organisational measures intended to reduce to a minimum exposure to mechanical vibration and the attendant risks…” 1 The PAD limit value is effective for new machines starting July 6, 2007 and for used machines by at least July 6, 2010. These requirements apply to the users of machines, but machine manufacturers will be challenged to provide machines and information to help the users comply with the directive. Caterpillar manufactures machines with the goal of enabling our customers to comply with all regulations dealing with health and safety. Caterpillar designs all of our machines to provide a safe, comfortable and productive work environment. This study was to determine if seat suspensions could provide a reduction in the vibration environment experienced by operators of Caterpillar mid sized (<50,000KG) Track Type Tractors Methods Seat manufacturers were asked to provide seat suspensions that provide improved isolation over and above current seat suspension. Each supplier was provided with ride profiles and was asked to demonstrate the vibration reduction on a shaker table. Two suppliers provided suspensions that were compared with the current seat suspension in a field study. Three full factorial experiments were conducted. The first experiment was to evaluate overall suspension performance for four operations. The second experiment was to determine the benefit of the adjustable vertical damper at three different levels and the third experiment was to determine the effect of the fore/aft and side/side isolators. Six operators were used for the study. Acceleration was measured at the seat base and at the operator seat pad. Both the transfer function and the ISO 2631 RMS ride values were used to determine the seat suspension’s effectiveness of isolating the operator from vibration. A structured questionnaire was used to determine the operators’ subjective assessment of the seat suspensions. Results There was significant operator-to-operator variability in the vertical direction (>35%), however there was little variability in the fore/aft and side/side direction based on seat base

Jan 6, 2006

By Oliver Bowles

Sandstone, a widely distributed siliceous sedimentary rock, is the third most popular building stone in the United States. It is formed by the breaking down of preexisting rocks by weathering, subsequent segregation of the detrital quartz grains into discrete deposits by the sorting action of water or wind, and finally cementation of the quartz sand into a coherent rock. The homogeneity and resistance to weathering of the resultant sandstone make it suitable for exterior construction. Its excellent wearing properties explain its popularity for flagging and stair treads. However, quarrying and dressing methods and costs are adversely affected by the abrasiveness and hardness of sandstone especially as compared to limestone.

Jan 1, 1963

By Samuel S. Wyer

The magnitude and economic importance of the problem of correctly valuing natural-gas leaseholds become evident when me consider that: (a) Natural gas is handled in 55 per cent. of the gas distributing plants in the United States. (b) Present known natural-gas acreage forms 47 per cent. of the total known mineral-land acreage in the United States. (c) Five acres of land are now required to protect and maintain continuous service to each of the 2,000,000 domestic natural-gas consumers in the United States. (d) The cost of acquiring and maintaining this acreage of an expendible resource represents a substantial part of the cost of the natural-gas service to the consumer. (e) "The right of a citizen by means of his ownership of or his mining leases on land to draw gas from beneath its surface is property and sometimes valuable property."&apos; A large number of other court decisions have established the basic legal principle that the right to drill for gas within a given area constitutes an interest in the land itself, and is necessarily an exclusive property right. Definition of Vested Interests or Rights "Vested interests are economic interests which are legally recognized to be such that they cannot be impaired by public action, directly or indirectly, without indemnification. Vested interests are largely property interests. The recognition of an interest as a vested interest gives it some of the attributes of property, and by American courts it would be comprised in their very inclusive concept of property. Otherwise than through property, vested interests generally arise through contract."

Jan 1, 1917

By Ronald Díaz

"Cerro Corona es un yacimiento porfiritico tipo stockwork con diferentes unidades geometalurgicas, las cuales son alteraciones producidas por una extensa familia de fallas geológicas que determinan un tipo especial demineralización. En ese sentido, a medida que la mina se va profundizando, la roca encajonante será menos alterada, así como se obtendrá una mayor dureza del mineral y los problemas asociados con el menor tonelaje de procesamiento. Por ello, el presente texto señala la optimización del procesamiento de minerales de bajo contenido de arcillas y alta dureza, así como la disminución de la malla de voladura, el incremento del factor de carga, Blending adecuado de mineral duro, la disminución del set de la chancadora, la instalación de cañones de aire en los chutes de transferencia, una mayor adición de bolas, los cambios en los diseños de linea, el control de desgaste de hidrociclones, sintonización de la lógica de control y el control supervisor del molino SAG, etc."

Sep 21, 2013

By Bern Klein, Tichang Sun, Daozhen Gong, University of Science and Technology Beijing, Chunbao Sun, Stefan Nadolski

"This paper is focused on the effect of modifying the SAG mill/ball mill transfer size on the energy efficiency of SABC circuits. The transfer size is considered to be a parameter which provides operators with the opportunity to improve comminution circuit performance. In this study, the Moly-Cop tools package was employed to predict the energy consumption of SAG mill and ball mill circuits under different operating conditions. An Energy Benchmarking model was adopted to calculate grinding energy efficiency. The SABC circuit at the Huckleberry mine was selected for this case study. It was observed that after increasing circuit transfer size (T80) from the existing 3.3 mm to 4.8 mm, the Benchmark Energy Factor (BEF) of the SABC circuit decreased from 4.30 to 4.05. In terms of energy consumption of the SABC circuit, 1.17 kWh/t of specific energy saving was achieved through the transfer size optimization.It was also observed that when a transfer size was selected such that both SAG mill and ball mill circuits operated at their highest energy efficient states, the entire SABC circuit was the most energy efficient. The maximum energy efficiencies of these three circuits were all approximately 25% when compared to the minimum practical energy required to carry out an equivalent comminution duty. Single-particle compression breakage testing was used to determine the minimum practical energy associated with the Huckleberry mill feed. In combination with geo-metallurgical data, this study also provides an opportunity to perform dynamic optimization of SABC circuits."

Jan 1, 2016

By Roger L. King

Working in gassy ground conditions is an everyday occurrence for the U.S. coal mining industry. As tunneling operators begin to venture into projects that expose them to the additional hazard of potentially explosive atmospheres, lessons learned by the mining industry over years of experience should be transferred into this industry. This paper will present practices developed by the U.S. coal mining industry for dealing with the problem of excavating material in potentially explosive atmospheres. Procedures will be discussed that can be used to detect and quantify gas prior to mining that have application to the construction industry. Degasification or drainage practices, including predrainage from vertical and horizontal boreholes, will be discussed. Also, ventilation practices commonly used in the mining industry will be presented.

Jan 1, 1985

By K. A. Brame, L. G. Austin, R. S. C. Rogers

The breakage parameters of phosphate ore were determined by batch first-ordering grinding studies in a laboratory ball mill according to the Austin, Klimpel, and Luckie procedures. The results were scaled to five larger mills of 0.56, 0.82, 8.36, 4.41, and 5 m in diameter assuming equilibrium ball charges for the full-scale mills. The results were used to predict product size distributions and capacities for batch grinding in the smaller mills and open-circuit grinding in the larger mills. The predicted capacities were in approximate agreement with experimental values except for the 5-m diam mill. The Bond method gave capacity predictions that were 4570 to 150% too high.

Jan 1, 1987