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By C. A. Sobotowski, J. Eagan

Computer programs applicable to coal mining have been available for some time, especially in the academic sector. However, the computer has not routinely been applied to actual mining operations. This paper discusses how a computer system was set up as an important tool in mining design and decision making. The project was completed within the allotted timeframe of two months by taking advantage of existing technology. Key points include the selection of programs to meet the specified needs of the project, conversion of the programs to be compatible with a computer of a different manufacture, simplification of the data entry process, development of procedures for using these programs, and an explanation of how the reports generated from the programs were used for mine planning and decision making.

Jan 1, 1983

In Bulletin J 1, recently published by the Traylor Engineering and Manufacturing Co., it is stated that the largest jaw crusher ever built has a jaw opening of 66 in. by 86 in. and weighs 680,000 1b. It is said to be in successful operation and has a capacity of 490 tons per hour crushed to 12-in. size; 415 tons per hour crushed to 10-in. size; 330 tons per hour crushed to 8-in. size. The same company, in its Bulletin G 3, gives a diagram showing the percentage of a crushed product which will pass through screens of different sizes of perforation from a machine adjusted to a certain size screen. This diagram is reprinted below for the information of our members and the following notes apply to it. In order to prevent an excessive amount of fines, crushing machines are usually set so that 15 per cent. of the product will be larger than the maximum size desired, and this oversize is then recrushed by smaller

Jan 10, 1916

By T. E. Schwarz

The publication of the report by Mr. F. L. Ransome1 was welcomed by many engineers who had mined in the heart of the San Juan country, braved its long and snowy winters, climbed its lofty peaks, run the gauntlet of its snow-slides, and studied its problems of geology, while making dividends for their English or American clients. This report helps one to understand why the bonanzas occurred, and why the inevitable " borrasca " presents itself where least expected. The Red Mountain district of Ouray county, a very productive section from 1884 to 1893, occupies considerable space in the report mentioned. The character of the ore-occurrence.

Jan 1, 1906

By T. K. Matthews

Minerals are mined as a one-time crop, and the processing of one ton of ore results in there being one ton less to be recovered from the deposit. Although some minerals occur in greater abundance than others, they are to a greater or lesser degree exhaustible. Depletion Allowances One of the distinctive features of the mineral industries is the allowance for depletion. The depletion allowance is a much maligned and misunderstood principal of our tax structure. Although imperfect in design, it has nevertheless served as a constructive incentive for the development and expansion of the minerals industry.

Jan 1, 1969

By Christopher Haycocks, J. Richard Lucas

The growth of computer and ground control technology in recent years, combined with an urgent demand for low-cost fossil fuels and mineral resources, has set the stage for full-scale utilization of computers in mine planning. Steeply rising production costs and the need to preserve the environment are placing great demands on engineers to improve their mining efficiencies, which can best be accomplished by applying the full capabilities of the computer. Pressure to develop and perfect programs with an immediate potential for improving mine design, reducing mining costs and extending the viable coal reserves of the country has already come to bear in the form of exploding energy requirements, environmental considerations and the visible limitations of other energy sources.

Jan 4, 1973

Although grinding mill liner life has been the subject of extensive studies, evaluation of the effect of liner design a power consumption, a far more significant part of total grinding costs, has been less comprehensive. The factors that effect ball mill energy efficiency are reviewed, and attention is then focused on the mechanism of grinding. The trajectory of the outer row of balls, with different lifting face angles, is derived. Basic recommendations for mill speed and liner configuration are also presented

Jan 1, 1984

By E. L. Mooney, D. F. Gibson, T. E. Lehman

This paper outlines the features of a computerized planning system, which was developed to aid surface mining and reclamation evaluation. Essential features of the system include three main modules: production, reclamation, and impact analysis. In addition, the system incorporates a large number of computerized data analyses and display features, which are described and illustrated in this paper.

Jan 1, 1983

By B. Stimpson, D. M. Ross-Brown

Borehole information is often the only source of information on rock conditions at depth during the stage of feasibility studies of a project, and from this data the rock mechanics engineer would like to make some quantitative estimates of rock mass cohesive strength. While judgement and experience will usually play a paramount role at this stage, simple tools for estimating rock mass cohesive strength would be an asset. In this paper, an approximate technique is suggested for assessing the cohesive strength of a randomly jointed rock mass from borehole data on fracture intensity and intact rock strength.

Jan 2, 1979

By A. M. Mirani

The Mine Planning System consists of two parts: 1. A Sales Forecast (Sales Planning) 2. A Production Planning. The mathematical methods of the sales forecast are the exponential smoothing and a method with Markov-Chains. By these methods the quantity of material (ore, coal) will be calculated for the time planned. These quantities constitute the points in the production-planning. In the production-planning , special kinds of networks are used for calculating the resources-equipment required, labor and costs. A special routine optimizes the sequence of the mining areas within the mine on the basis of the lowest costs. The resources can be limited. The activities will be shifted when the demand exceeds this limit. The basis of the production-planning are computer files, in which the geological data and economical evaluations are stored.

Jan 1, 1969

By L. D. Muller, C. P. Sayles

When minerals are mined in arid or semiarid areas where water is at a premium, dry processing is a natural route to take for concentrating or classifying the values. Until recently though, dry processing technique were limited by the lack of suitable equipment. With the advent of the pneumatic pinched sluice at Warren Spring Laboratory, Stevenage, Hertfordshire, England, a new tool emerged to fill this gap and it has the potential of providing industry with a high output concentrator or preconcentrator for dry natural ores and secondary materials. The pneumatic pinched sluice gives every indication of fulfilling these requirements with the added advantage that with homogeneous materials-such as crushed limestone or quartzose sands-it may alternatively operate as a high throughput dry classifier or sizing device. An industrial version of the equipment is now being manufactured by Dryflow Separators Ltd., as sole licensee for the National Re- search Development Corporation.

Jan 1, 1971

By Robert Glass Cleland

THE DEVELOPMENT of the Phelps Dodge copper and railroad interests began in one era of the company's history and continued unbroken into the next. Yet the two eras themselves were strikingly dissimilar and represented marked differences in the company's activities, corporate structure, and personnel. From its organization in 1834 almost to the end of the first decade of the twentieth century, the partnership known as Phelps Dodge was directed, managed, and controlled by the family dynasty established by Anson Greene Phelps. The last two directing partners of this three-generation-old regime assumed control of the company's affairs in 1879 when the economic revolution that followed the Civil War was well under way.' They lived in an age of gigantic undertakings, gigantic enterprises, gigantic combinations, gi- .

Jan 1, 1952

By W. A. Boyer

Mine hoisting ropes can be loaded to capacity only when the strength of each component is exactly known. Characteristic curves provide this information. When load and rate of acceleration are specified for an individual rope, the characteristic curve assumes a predetermined shape. The factor of safety is the value derived by dividing the breaking strength of the rope by the total stress on the rope where it goes over the sheave wheel. Total stress is made up of the weight of skip and cage, weight of ore, weight of rope between sheave and rope clevise or attachment, friction load, and acceleration force. Bending stresses are neglected in this discussion, as sheaves and drum diameters are assumed to be large enough to reduce these stresses to a negligible value.

Mar 1, 1956

By R. P. Carreker, R. L. Fullman, J. C. Fisher

CREEP tests are usually constant load tests. As deformation occurs, the cross section of the specimen changes so as to maintain approximately constant volume. Until necking starts, A _ l0 A0 - 1 where A is the cross-sectional area, 1 is the specimen length, and the subscript o indicates initial values. Thus, during a tensile creep test under constant load, the stress increases in proportion to the elongation. A A, 1, where S is the stress and F the load applied to the specimen.

Jan 1, 1954

By C. M. Loeb, A. M. Gaudin, J. H. Brown

R. E. Carter (General Research Laboratory, Schenec-tady, N. Y.)—Brown, Gaudin, and Loeb in their study of intergranular comminution by heating attempt to find one explanation for all types of rock in terms of the properties of the phases present. The only necessary condition for intergranular cracking by heating is the setting up of high stresses at the grain boundaries. Such stresses may be set up in multiphase isotropic mixtures if the thermal expansions of the phases are different, in non-cubic single phases because of the anisotropy of thermal expansion in the various crys-tallographic directions, and in materials containing quartz because of the a-p' transformation at 575°C. In addition, for intergranular comminution by heating, the cooling and not the heating is most important.

Jan 1, 1960

The Library of the above-named Societies is open from 9 A.M. to 10 P.M., except on holidays. It contains about 70,000 volumes and 90,000 pamphlets, including sets of technical periodicals and the publications of scientific and technical societies. Members of the Institute, with few exceptions, are forced to spend a portion of their time in localities isolated from sources of information. To these the Library, through its Library Service Bureau, can render valuable service through correspondence; letters requesting information will receive especial attention. The Library is prepared to furnish references and photographic copies of articles on mining and metallurgical subjects; to determine the existence of mining maps, and to furnish general information on the geology and mineral resources of all countries. All communications should be made as definite as possible so that the information received may be what is desired and not include collateral. matter which may not be of interest. The time spent in searching for such collateral matter will be saved, and the information will be sent more promptly and in more usable shape.

Jan 3, 1917

By W. F. de Lange, M. I. Brittan

A mathematical model of the Western Holdings gold concentrator in South Africa was generated by multiple regression analysis of routine plant operating data. Interpretation of the computer results and application of the model indicated that significant economic improvement in gold recovery could be realized by relatively minor modifications to the circuit. The modifications made are described and the economic benefits resulting from the increased gold production are assessed. Comparison, of the projections of the mathematical model with actual plant performance is illustrated.

Jan 1, 1976

By John D. Weibmer

A remarkably simple construction system that derives its internal stability from metal straps buried in backfill is finding diverse mine applications, ranging from rock crusher headwalls to massive slot coal storage facilities. Reinforced Earth (Re/Earth), the system trade name of Reinforced Earth Co., is proving itself 20-50% less expensive than alternative earth embankment structures, and in the case of cast-in-place concrete walls, six to seven times faster to erect. While the majority of applications are in the realm of civil engineering-projects such as retaining walls, bridge abutments, slide buttresses, and containment dikes-a growing proportion is mine related. Of the estimated 120 Reinforced Earth projects that will be completed this year, company president David P. McKittrick expects mining to account for about 20% of the business volume.

Jan 8, 1978

By Kerstin Malmqvist

A prospecting project for deep-seated sulphide ore bodies will be expensive and means a considerable economic risk. The high costs depend on the demand for extensive drilling. It is therefore important to find effective methods to estimate the outcome of different prospecting strategies. The results from a preliminary study of the possibility of using mathematical methods for this purpose are presented. We have found that mathematical methods, especially simulation technique, might be an important tool in such exploration work. A mathematical model of an ore field and of a drilling procedure has been constructed. A set of parameters describes the geometry, the size distribution and the intensity of ore bodies. Another set describes the geometry and the intensity of drill holes. Some preliminary results are given of Monte-Carlo simulations and probability calculations.

Jan 1, 1977

By M. J. Scoble, N. Rowlands, L. Piciacchia

Pronounced non-linear behaviour of mine backfill arises from the influence of confining pressure, cementing agent content, curing time, void ratio and water content. Past research into backfill behaviour under stress is reviewed and related to the needs for constitutive laws which can be integrated into numerical modelling for mine design where structures employ backfill support. A method for representing non-linear backfill behaviour is proposed, which is based upon numerical regression treatment of triaxial laboratory data. The non-linear behaviour observed from a program of laboratory triaxial testing of cemented hydraulic backfill is presented. The particular influence of confining stress and curing duration is high- lighted. The paper concludes by considering the alternative means of accounting for such behaviour in mine design.

Jan 1, 1984

By P. K. Koh, L. S. Birks, J. M. Siomkajlo

Direct identification in situ of x and a phase precipitates in stainless steel is possible with the electron probe microanalyzer. Although particles in the 1 p size range are too small to yield absolute percent composition, the relative % Crfi Mo ratio can be used to distinguish the two phases with better than 95 pct confidence. Wet chemical analysis of extracted residues gives Cr/Mo ratios in good agreement with electron probe results extrapolated to the 4 to 5 p size range. WHEN stainless steels are subjected to extended heating in the temperature region around 1600°F, precipitation of the brittle 0 or x phases may occur and impair the properties of the material. Identi-

Jan 1, 1961