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By Dean David

The evaluation of a new mineral sands prospect with unusual characteristics is described, The heavy minerals are very fine grained, have comparatively low average specific gravity (3.6) and are altered. Poor performance by conventional processing techniques made it necessary to trace the response of the major minerals during the separation processes, QEM*SEM® was used to quantify mineral volumetric abundances and mineral locking in magnetic and gravity separation products.

Jan 1, 1989

By R. P. H. Willis

Uranium is back on the radar. Uranium has always been a controversial metal, from its role in the arms race to its claim to be the only viable alternative to fossil fuel. This paper will cover its properties and use, its occurrence and production in South Africa, the current market drivers and its future role as a primary energy fuel. It will highlight the difference between uranium used to make a bomb and uranium used in a power station. The recent significant uranium price rise will be put into context of the market drivers including geopolitical issues. Planned expansions in nuclear power station capacity will be reviewed, as will new mine production. Future demand will also be speculated on.

Jan 1, 2006

By Emil H. Geus

A process has been developed to recover aluminum from dross which does not require the use of salt flux as commonly employed, This results in a salt-free residue which has potential industrial uses or alternatively can be safely land-filled. The dross is first heated by an air-fuel or oxy-fuel burner in a sealable rotary furnace. At a suitable temperature the burner is turned off and the temperature of the dross thereafter controlled by means of an atmosphere of oxidative and inert gases. When the free metal has agglomerated it is first discharged from the furnace, followed by the residues.

Jan 1, 1995

By D. Crouse

A significant wollastonite resource has been discovered and evaluated near Seeley's Bay in southeastern Ontario. The deposit occurs in Grenville Frontenac Terrane granulite facies rock within a calc-silicate skarn in contact with Proterozoic-age gabbro. The steeply-dipping and tightly-folded wollastonite skarn beds are interlayered with diopside and quartz-feldspar skarns in a southwest-plunging synclinorium. More than 9 million tonnes of a drill-proven and inferred resource grading 41 % wollastonite has been identified, as well as an additional 3 million tonnes grading 30%. Mineralogical and process test work with the wollastonite from this deposit has demonstrated the potential to produce a high purity, high aspect ratio wollastonite product.

Jan 1, 1994

By S. L. May

Procedures for separating columbium and tantalum have been developed by the Bureau of Mines as part of a broad research program on the utilization of low-grade ores of columbium and tantalum, Columbium and tantalum compounds of greater than 99 percent purity have been obtained by application of the solvent extraction separation system: Hydrofluoric acid-sulfuric acid-methyl iso-butyl ketone. This system is unique in that it not only separates columbium from tantalum, but also separates these two metals from other metallic impurities. The system is effective for separating the metals irrespective of the tantalum and columbium ratio of the starting materials. Investigations in which the spent feed obtained from the initial coextraction step was recycled to the system indicated that efficiency was increased, and cost was reduced without impairing product purity. Continuous tests demonstrated that this solvent extraction system could be used in large-scale equipment without loss in efficiency or in purity of products. The separation of columbium and tantalum has been difficult because of the similarity in their chemical bahavior. Many methods have been proposed for separating these two elements, but most methods either did not achieve satisfactory separation or were tedious and time consuming. The Marignac process (3, 4)4 developed in 1866 was the only method used commercially until recently. This separation procedure is based on the difference in solubility in aqueous solution of potassium tantalum fluoride and potassium columbium oxyfluoride. Current commercial practice appears to favor solvent extraction as a method for separating tantalum from columbium (1). Several efficient methods for separating columbium from tantalum by solvent extraction (2, 9, 8) were reported earlier from this laboratory.

Jan 1, 1961

By G. Kraemer, J. A. Le Gac, P. R. ZETTWOOG

I. INTRODUCTION During the course of our activities in assisting mining companies, we have had access to the monitoring results for personnel from a large number of uranium mines. The results differ greatly from one mine to another. One of our objectives has been to discover the origin of these differences. It is evident that they are largely due to variations in the geological context, to mining methods, and to the organization of the work ; but we also found that the rigor with which measures are implemented to prevent the personnel from being exposed to radiations is also a cause. In order to advise mining operators effectively, we have asked ourselves the following question Given the dosimetric results of a mining site, how can it be known - if occupational exposure has been reduced to the lowest possible level (dose optimization principle recommended by the ICRP) ; - if the exposures were justified, which would not necessarily be the case following a questionable choice of the mining method, for instance, or a lack of efficiency in the maintenance and repairs of ventilation apparatus or even an excess of radiation protection. It is necessary to establish some criteria, while taking into consideration the specific conditions for each mine, in order to determine whether a mining company is adequately implementing radiation protection procedures. This need led us to attempt a modelization of the occupational exposures of uranium miners ; the preliminary phase is presented here. Although voluntarily still very basic, this model makes it possible to demonstrate the role of certain dynamic or passive variables. Moreover, the model presents the concept of specific irradiation of a mining site equal to the collective dose received per ton of uranium metal supplied to the uranium mill. The specific irradiation can therefore be used to indicate the effectiveness of radiation protection procedures at a given mining site. This model can be used for - previsional exposure studies based on the use of data gathered at each site, making it possible to compare various work methods and to determine prevention means ; - qualification of "radiation protection" procedures at a mining site ; - detection of unjustified exposures ; - research of ways to reduce inevitable exposures. 2. DETRIMENT TO BE ASSOCIATED WITH A GIVEN EXPOSURE DISTRIBUTION Respecting exposure limits ensures that delayed stochastic effects are the only health risks to workers. If the hypothesis of linearity in the dose-effect relationship is applied, the detriment to a group of workers is proportional to the sum of exposure for all the workers, or the collective exposure usually expressed as man x rem. On this point the linearity of effects hypothesis makes it possible to consider that two different standard deviation distributions having the same mean value are equivalent. It would be possible, then, to reduce the standard deviation by changing the distribution of workers at the various working places without changing the mean exposure value. In other words, without taking into consideration the practical implications, individual limits can be respected by rotating the personnel or by reducing the individual working period which would be compensated by increasing the number of workers. The collective dose would remain the same, which would justify the use of the concept of collective exposure. 3. "RADIATION PROTECTION" QUALITY INDEX AT VARIOUS MINING SITES Each mining site is responsible for its own collective dose, but it is also responsible for producing a certain amount of uranium metal in the ore sent to the uranium mill. These two quantities must be brought together in order to establish the "radiation protection" quality index of a mining site. This quality index, called-specific irradiation (Ir) is expressed in rem.ton -1 for external irradiation, in mJoule.ton-1 for inhaled [a]-energy, and in Ci.ton -1 for inhaled radon *. The specific irradiation represents the health hazard which must be associated to the extraction of one ton of uranium metal. Figures la and lb present a system of coordinates for which the axis of the abscisses is graduated in tons of U metal and the axis of the ordinates is graduated in units of collective exposures. In the EEC, the regulation is based on the measurement of the amounts of radon 222 inhaled.

Jan 1, 1981

By S. E. Bretherton

Most metallurgists appreciate the great need of a process for the extraction and recovery of valuable metals from complex ore, where the presence of one metal increases the cost of extracting the other rnetals to such an extent that not any of the metals can be extracted at a profit. We need only refer to some of the mines in Colorado, Utah, and New Mexico, where oxidation has taken place and the sulphur, zinc, copper, and some of the iron and other metals have been leached out, large bodies of oxidized ore remaining, rich in lead, silver, and sometimes gold. These metals have been concentrated by the removal of the other metals, leaving a very desirable ore for treatment in the blast-furnace for the production of lead bullion, and recovery of the silver and gold. If lead is not present, the gold and silver metals are usually recovered by some method of milling, or the ore is shipped to a smelter, where it is mixed with lead ore or copper-iron sulphide ore from some other mine. In these same mines, when developed to greater depth below the leached or oxidized zone, the ore is found to contain the original mixture of sulphur, zinc, copper, etc., added to, or I should say left with, the lead, silver, and gold values; but instead of adding to the value of the ore, the presence of these elements, especially zinc, makes the copper, silver, and gold of less value, and often worthlees. Such was the experience of the oldest mines in Leadville,.Colo., until methods of mechanical separation of the lead from the zinc were developed sufficiently to allow of some profit by the making of a concentrate rich in zinc to be shipped to the zinc smelter, and sometimes a lead concentrate which could be shipped to the lead smelter; but even in these cases the waste of the different metals is a very serious matter. In the very best concentrating plants some zinc will be left in the lead concentrate, to be lost and to give considerable trouble in the lead-smelting furnace. On the other hand, some of the lead, with a large percentage of the copper and silver, will follow the zinc into the zinc concentrate, to be, perhaps, recovered by smelting the cinder or clinker left in the re-

Jan 1, 1915

By Gillies A. D S

Replies to a comprehensive questionnaire on mine water resource management systems (WRMS), which were distributed to a selection of Australian mining operations in 1991, are analysed. Although the replies cannot be considered fully representative of the industry, they do provide a good qualitative indication of water resource management in the industry at that time.Within Australia's largely arid land mass, a majority of mines nonnally need to conserve water, a few need to dispose of water and a number face a seasonally varying position. An assessment of the importance of WRMS compared with management of ore extraction and processing is given. A risk assessment of failure is given; there is more acceptance of WRMS failure in the mine compared with the mill. An assessment is made of considerations in WRMS design. Managements are generally pro-active in the design of WRMS and in the setting of perfonnance standards. The operational characteristics of mine systems are examined in detail.Companies generally do not appear to allocate sufficient resources for the collection of basic WRMS monitoring data and knowledge of the water budget to efficiently manage the system. This indicates scope for considerable cost savings in most mines.

Jan 1, 1995

By D. M. Buck

greatly restricted and every effort is being made to do away with it where possible, and to substitute a lead-base babbitt or a babbitt with 50 per cent,. tin. The amount of solder having the composition 50 lead, 50 tin, used by the Pennsylvania Lines East, during 1917, was approximately 100,000 lb., but there is reason to believe that a large portion of this can be replaced by a 60-lead, 40-tin solder with satisfactory results, and instructions have been issued to this effect. Inregard to the quantity of new tin used, it is not possible to give the amount, except approximately and from calculations based on the 1917 consumption of bearing metals by the Pennsylvania Lines East only, it is estimated that about 770,000 Ib. of new tin were required in a total of about 21,380,000 lb. of all kinds of bearing metals turned out by the foundry or purchased in the market. No change has been made in the specifications for bearing metals for some years, as the metals used have been satisfactory. A large proportion of the bearing metals are made up from old material re-melted and brought to standard composition by some addition of new metal, and every effort is being made to utilize old material to the best advantage and reduce the amount of new metal of all kinds purchased. For a number of years no tin has been used in the lining metal of either passenger or freight car journal-bearings, except such small amounts as come in from re-melting old linings. No change has been made in phosphor bronze used for rod bushings, as we should expect some trouble from bushings pounding out of shape if a phosphor bronze were used which contained less tin or more lead than the present specifications call for. In this, as well as in the case of all other bearing metals, we expect to use our utmost endeavors to economize and to substitute for tin wherever possible. The Tin-plate Industry D. M. Buck,* Pittsburg, Pa.—During the first 5 months of 1918, approximately 11,000,000 Ib. per month of pig tin were consumed in the United States. Solder, bearing metals, bronzes, etc, used about 5,500,000 lb.; collapsible tubes a little more than 250,000 lb.; tin-foil about 500,000 lb.; and the tin- and terne-plate industry somewhat less than 5,000,000 Ib. In an effort to reduce this consumption and thus conserve our tin supplies, several methods of procedure suggest themselves: 1. Salvage. The most careful and systematic collection and re-use of tin and tin-bearing materials is economically important, in that we thus

Jan 1, 1919

By T. Chikande

"Falls of ground pose costly hazards to personnel and equipment and thus measures should be taken to prevent them. This study endeavours to improve the support systems used in geotechnically poor ground at a Zimbabwean platinum mine by analysing the status quo and recommending an effective support system. Various techniques were used to determine the quality of ground conditions, predict the rock mass behaviour, and to identify the appropriate rockbolt type. An analysis of the current ground control methods and their limitations was also undertaken.The results showed that the current support system and mining practices in poor ground need to be modified to improve safety and productivity. Stoping overbreak is influenced by poor ground conditions and the explosives currently used. The use of emulsion is recommended to replace ANFO. Redesigning of pillars is also recommended in poor ground conditions. An evaluation of the current roofbolt system indicated an opportunity for improvement. With new insight on the performance of the shorter length roofbolts currently in use, a new support system was recommended taking into consideration cost-benefit analysis. Barring down using pinch bars in poor ground was seen as a risky and time-consuming exercise, hence the use of mechanical scalers is recommended to achieve zero harm and to meet production targets. Smoothwall blasting is recommended in poor ground to minimize excavation damage. Other recommendations include the use of hydrological surveys to determine groundwater levels and implement corrective measures. Both empirical and numerical modelling approaches need to be utilized in determining the optimum support. IntroductionThe presence of geological discontinuities such as faults and joints weakens the rock mass. Adequate support is critical in achieving zero harm in underground mines. This paper reviews the current support systems used in poor ground conditions at a Zimbabwean platinum mine. The area of research is located on the Great Dyke of Zimbabwe. The mine exploits platinum group elements (PGEs) and base metals. It is shallow, having a maximum depth of less than 300 m. The Great Dyke is the second largest reserve of PGEs, following the South African Bushveld Complex (Oberthur et al., 2012). It is a linear layered intrusion that extends for about 550 km with a maximum width of 11 km (Prendergast, 1989). The generalized section of the Great Dyke is almost like a trumpet, comprising layers that dip towards the centre. The reef exploited at the mine, the Mineralised Sulphide Zone (MSZ), is located in the pyroxenite layer, which is hosted in the ultramafic sequence. The MSZ is a uniform layer about 2– 3.5 m thick, dipping at around 10–14° from surface outcrop towards the axis of the basin, and located between bronzite and websterite horizons. The visible disseminated sulphide mineralization shows a typical and consistent vertical distribution of platinum group metal (PGM) and base metal values. The research was undertaken to review the current support systems used in geotechnically poor ground conditions in a bid to improve both safety and productivity."

Jan 1, 2016

A resource rent taxation scheme is based on the concept of taxing the rent or surplus profit generated from primary industry activity. Rent has been defined as profits that remain after deduction of company income which corresponds to the minimum return necessary to attract private investment to a new project.Rent taxation schemes on the mining industry within the Australasian region have been examined and widely discussed during the decades of the 1970s and 1980s. Forms of resource rent taxation schemes have been imposed on Papua New Guinea mining, some sectors of Australian petroleum, the Roxby Downs venture and are being discussed for the New South Wales coal industry. While no introduced applications have been pure rent taxation schemes, the concept has generally come to encompass arrangements which tax rent at a partial rate which may or may not vary with the level of profitability or return.An examination is made of a number of the more recent schemes. Aspects which should be considered in implementation of new forms of this taxation are discussed. It is concluded that there is an increased acceptance for this form of taxation on the Australian mining industry.

Jan 1, 1990

By d&apos, D. L. Guernsey, J. C. Entremont, John Chipman

The reaction of aluminum with oxygen in liquid iron has been studied at 1740° and 1910°C. Interaction coefficients are very much smaller than those previously published. The equilibrium constant falls within the approximate range of earlier experiments and calculations. It is now well established that the "deoxidation constant" for aluminum in liquid steel at normal steelmaking temperatures is extremely srnall. Thus at 1600 the product [% Al] is of the order of 10- 14. At this temperature, therefore, great experimental difficulties are encountered in any attempt to obtain a direct measure of the constant. If the aluminum content of the metal is high enough to permit accurate analytical determination, that of the oxygen is too low. If the oxygen content is high, the aluminum is below the limits of detection. Our best values of the constant have come, therefore, from indirect calculations or by extrapolation downward from observations at higher temperatures.. For their studies in the range 1695° to 1866°C, Gokcen and chipman' restricted their aluminum concentrations to less than 0.06 pct. Oxygen analyses were made by the vacuum fusion method which appears to be dependable at these low aluminum concentrations. Experimental results, even at the highest temperature employed, are extremely sensitive to small errors in the analysis of either element. The slight change in the equilibrium constant with aluminum and oxygen concentration was utilized in the calculation of interaction coefficients expressing the effect of aluminum on the activity coefficient of oxygen and the reciprocal effect of oxygen on the activity coefficient of aluminum. The range of concentration, however, was so limited that only a rough value for the interaction coefficient could be obtained. This value was much more negative than that found for any other pair of reactants. In view of the very limited range of concentration employed, the reported values have always been regarded as very questionable. A redetermination was the object of the work reported here. EXPERIMENTAL METHOD At high aluminum concentrations, the vacuum fusion method is susceptible to grave error due to absorption of gas by aluminum distilled from the sample. Since it was desirable to extend the study to at least as much as 1 pct Al, another method for analysis was sought. In steels containing more than a few hundredths of a percent aluminum and no other deoxidizing element, it is safe to assume that

Jan 1, 1963

By E. Jackson

This paper describes highlights of the Placer Dome MiniMole project - the development and testing of a robotic machine for mining narrow ore veins. A prototype hydraulically controlled robotic machine was built and tested. The machine provided a platform for testing numerous cutters in the field. Other cutters, e.g. undercutting devices, were tested in the lab. Extensive analyses were done on specific energies and cutter penetration. Three sets of quarry trials were done, then the machine was tested in an underground mine. Rock UCS values varied from 180 MPa to 230 MPa. The paper includes lessons learned and recommendations based on the project findings.

Jan 1, 2007

By Donald Thompson, Jessie Bonner, Ileana Tibuleac

Predicting ground motion from complicated mining explosions is important for mines developing blasting programs in regions where vibrations must be kept below certain levels. Additionally, predicting ground motion from explosions in complex 3D media is important for source size estimation for nuclear treaty monitoring. Both problems have been addressed under the development of a new series of programs including: 1) Generalized Fourier Methods to generate synthetic seismograms (Green’s functions) in 3D media for a moment tensor source implementation and 2) MineSeis3D, a program that simulates seismograms for delay-fired mining explosions with a linear relationship between signals from small size individual shots. To test the programs, three-component seismic recordings of three production shots at an iron mine in northern Minnesota were compared to synthetic waveforms in 3D media. Comparison of the observed and synthetic waveforms shows promising results. The shape and arrival times of the normalized synthetic and observed waveforms are similar for most of the stations. The synthetic and observed waveform amplitude fit is best for the vertical components in the mean 3D model but not as promising for the transversal components. The observed effect of spall on the waveform spectra was weak in the case of fragmentation delay-fired mining explosions. Commercial applications of the code could provide data needed for designing explosions that do not exceed ground vibration requirements posed by the United States Department of Interior, Office of Surface Mining.

Jan 1, 2005

By P. J. Rua

The Piedras Verdes copper mine is a new run-of-mine (ROM), heap leach, solvent-extraction/electrowinning (SX-EW) operation located 21 km (13 miles) north-northwest of the town of Alamos in the state of Sonora, Mexico. The Piedras Verdes copper mine is wholly owned by Frontera Copper Corp. (FCC), a Canadian corporation, through its 100 percent beneficial interest in Cobre del Mayo S.A. de C.V. (CDM), a Mexican registered company. The January 2008, minable reserves were estimated to be 193.6 Mt (213 million st) at a grade of 0.36 percent copper. The overall recovery of total copper was estimated to be 61.9 percent. The property has an additional 17-year life and is designed to produce 31.7 kt/a (70 million lbs/year) of cathode copper. Construction commenced in early October 2005. The first copper cathode was produced 12 months later at a total capital cost of $100 million. Elevations at the site range from 150 to 300 m (490 to 985 ft) above sea level. The area has excellent infra-structure in the form of towns, power, water, roads, rail, airfield and access to the deepwater port of Guaymas (Fig. 1). The surrounding area is also famous for its numerous polymetallic (lead, zinc, copper, silver and gold) epithermal veins. Some of these were mined for more than 200 years and provided the wealth on which the town of Alamos was built. The original village of Piedras Verdes was located in the area of the proposed openpit mine and, consequently, it was necessary to construct a new townsite 6 km (3.7 miles) to the south before project development could commence. The new town site (Fig. 2), complete with power and water supplies, roads, sewer system, schools, clinic and recreational facilities, was completed and occupied by 49 families in September 2005. CDM received its remaining permits from the Mexican environmental authorities on Sept. 20, 2005. This enabled the company to proceed with full-scale development. CDM owns or controls 27 mining concessions covering the resource. Surface rights to the Piedras Verdes project were controlled by four Ejidos (communal agrarian and/or ranching societies) and five individual landowners. CDM has acquired all surface rights necessary for its mining operations and associated facilities either through outright purchase or long term lease agreements.

Jan 1, 2008

By R Van Laeren, G Langerak, S Fityus, K Koosmen

Co-disposal of partly-dewatered mixed-plant rejects (MPR) from coal processing into spoil dumps is gaining favour amongst Australian coalmine operators in preference to conventional tailings disposal methods which require a tailings dam. Owing to their often low permeabilities and high degrees of saturation, MPR materials may be prone to the development of excess pore pressures when covered by spoil during routine dump advancement. The likelihood of dump failure will increase if these pore pressure regimes and the associated delay of shear strength development are not accounted for during waste dump design. To date however, little is known about these pore pressure regimes due to the complexities associated with their in situ measurement.This paper describes the in situ measurement of pore pressures in a cell of MPR placed within a coalmine spoil dump. Four vibrating wire piezometers (VWPs) were placed within a cell that was then filled with MPR and allowed to consolidate under self-weight before advancing an adjacent tiphead across the cell. The VWPs recorded the transient pore pressures during MPR placement and dump construction, and their interpretations are described within the context of laboratory measured parameters. Following analysis of the measured pore pressures, their implications on shear strength and dump design are also discussed.CITATION:Koosmen, K, Langerak, G, Simmons, J, Fityus, S and Van Laeren, R, 2015. Field measurement of transient pore pressures within co-disposed processing rejects placed in a spoil dump, in Proceedings Tailings and Mine Waste Management for the 21st Century, pp 63–72 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 27, 2015

By John Birkinbine

(New Haven 'Meeting, February, 1909.) AWAKENED public interest in efforts to conserve natural resources will certainly be appreciated by the members of the American Institute of Mining Engineers, and a discussion upon conservation may well form a part of one of the Institute meetings, for the records of papers and discussions which appear in the 38 volumes of its Transactions are replete with evidence of effort's in this direction. Every process which reduces the fuel consumed or the power applied per unit of product; every utilization of waste material, or employment of that formerly rejected, to obtain something of value ; every feature of construction or operation which lessens the labor required or increases the output per employee, is an advance in the direction of true conservation. This may not appear from the records of late conferences or from published articles, in which the effort seems to be concentrated upon reducing the consumption and presenting to the people of the country estimates of exhaustion of natural resources. I rejoice in the awakening of public interest in a matter so important for the present and future welfare of our nation; I appreciate the possibility of much good following conferences of the Governors and delegates from various States and from national societies; and I recognize the interdependence, not only of different States, but of contiguous nations. In fact, the marvelous development of transportation by land and by water, and the decreasing rates at which commodities can be moved great distances, have in many cases practically obliterated geographical boundaries, and nearly every country on the globe can either market its product in other lands or draw upon them for raw or manufactured materials ; hence, conservation is an international subject.

Apr 1, 1909

By S. D. Thompson, L. Adler

J.R. Sturgul Thompson and Adler (1988) present a new simulator for use in designing conveyor belt systems for underground mines. Their model uses a large Fortran program to do a Monte Carlo simulation. Their approach is similar to that done by other researchers, such as Stanford (1965) and Newhart (1977). All Fortran based simulation models use an imaginary clock that is advanced a time increment. At each advance of time increment the program has to determine what is to take place in the system. Since many things can take place at different places in the system, this approach requires that a large amount of logic is needed at each step of the program. This, then, necessitates a great amount of jumping between different portions of the program. In fact, the Fortran program, CMBCS, takes up to 15 to 20 minutes to run on the mainframe and several hours for the PC. Such execution times are typical of Fortran based simulation studies. There have been other examples of Fortran based simulation studies in mining. Cross and Williamson (1969) presented a model of a working open-pit copper mine. Fosinato (1982) presented a model of the bucketwheel excavators for the large open-pit mines in Southern Victoria in Australia. These excavators discharge into a complex conveyor system, which can be thought of as being similar, but more complicated than the one modeled by CMBCS. All previous simulation studies using Fortran as the source code have several things in common: they all are very lengthy, often being of the order of 10,000 lines of code and take a great deal of CPU time to execute. The program of Fosinato takes more than 4.5 hours to run on a large mainframe. Also not mentioned by Thompson and Adler is the actual time it took to write the Fortran code. This, too, can be considerable, as Fosinato's program took several man years to write and de-bug. In order to change it, as the parameters change or as the mine increases, further large amount of time is needed. An alternate to such Fortran based programs is provided by using a special computer language known as General Purpose Simulation System (GPSS). This language is designed to solve a wide variety of discrete event simulation problems and appears to be particularly suited for mining situations as shown by Sturgul and Yi (1987). Although GPSS was introduced as far back as 1961, it has not been used in mining to any great extent. However, the original form was quite crude and inefficient compared to modern versions. Perhaps with the increasing popularity and availability of these recent versions, this will change. Two such versions are GPSS/H for the mainframe and GPSS/PC for the personal computer. GPSS/H allows for interactive usage, such as allowing input data to be entered via a menu. GPSS/PC has excellent graphical capabilities and one can actually view the simulation in progress. In addition, one can halt the simulation and change values of various parameters. If a particular portion of the simulation is in progress via a concept known as "microwindows." These new versions have greatly increased the potential for using the language for mining situations. Mining applications of GPSS have been given by Sturgul and Yi (1987), Sturgul and Harrison (1987), Sturgul (1987), and Sturgul and Singhal (1988). Schriber (1987) presents a summary of the recent advances in GPSS.

Jan 12, 1988

By C. H. Hitchcock

The puiblication by the Institute of a small geological map of the United States calls for an explanation of its peculiarities. The title intimates that it is intended "to illustrate the schemes of coloration and nomenclature recommended by the International Geological Congress." By way of further explanation it is said to be "based, by permission of the Director of the United States Geological Survey, upon the map published in his Fifth Annual Report, the portions not colored in that map being here supplied from other sources." The map referred to was prepared by W. J. McGee, and in the text of the report containing it he has given a list of the authorities employed in the compilation. The scheme of coloration used for the map was the one proposed by the Director, in the Seeond Annual Report, for the publications of the United States Geological Survey, which differed materially from those employed by the older American geologists. Because of the increasing diversity in the particular colors employed to represent rocks by geologists in different countries, and of the existence of very dissimilar schemes of nomenclature, it seemed best to the American Association for the Advancement of Science, at its Buffalo meeting in 1876, to appoint an international committee of geologists, who should consult together, and, if feasible, to call an International Congress to discuss these subjects. The proposition met with favor, and the meeting was called. The first session was held at Paris, in 1878, when geologists were present from twenty different countries. Once organized, the Congress has perpetuated itself, enacting regulations for its conduct, choosing the French language for its medium of communication, and arranging for the compilation of a geological map of Europe upon which the perfected schemes of coloration and nomenclature will be delineated. The American Association maintains a standing committee to represent it at the international sessions, and to report their proceedings. Sixteen countries were represented at the second Congress, at Bologna;

Jan 1, 1887

By Robert W. Thompson, Darry A. Ferguson

In August, 1977 the United States Congress passed Public Law 95-87 which has been commonly referred to as the Surface Mining Control and Reclamation Act (or SMCRA). This title is somewhat misleading in that the act creates as many regulatory requirements for underground coal mines as for surface coal mines. How- ever, this paper will concentrate on the effects of SMCRA on designs and stability for various activities of surface coal mines, specifically those concerning "Disposal of Excess Spoil". In the past, the objective of most laws and regulations applicable to the mining industry has been to achieve goals of safety or environmental concerns for all types of mining. However, SMCRA is unique in that it sought to regulate-all-activities of coal mining from initial data gathering, exploration, mine design and facilities design to reclamation activities and design. More specific to the stability of the activities of surface coal mining, special criteria for design and construction performance standards have been promulgated for the construction and maintenance of roads, dams and embankments, coal processing waste, ex- cess spoil piles, backfilled reclamation and pit slides. The criteria for design for the previously mentioned facilities has been enumerated by regulations and in many ways restrict the use of site specific design parameters. The restrictions imposed by regulations significantly inhibit the engineer's ability to develop the best practical and economical design and in some cases may re-

Jan 1, 1983