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By Jr. Jacobson

Thermal reactions of l-methylpyrrole, l-butylpyrrole, and l-isopropyl-pyrrole were investigated by a flow method in the temperature range of 4500 to 5750 C. Those of I-butylpyrrole and l-isopropylpyrrole were also investigated in the 3400 to 4000 C range in a static system. The I-substituted pyrroles isomerize by an irreversible reaction to 2-substituted pyrroles. A reversible isomerization reaction shifted the alkyl group from the 2-to the 3-position on the pyrrole ring. All of the isomerization reactions are homogeneous, unimolecular, nonchain, first-order reactions having similar mechanisms and transition states. There is decomposition and cleavage of the longer alkyl side chain when it is in either the 2-or 3-position giving, as products, pyrrole, 2-and 3-methylpyrrole, 2-and 3-ethylpyrrole, pyridines, and hydrocarbons. The decomposition reactions appear to be by free-radical mechanisms. Pyridine homologs are formed by the expansion of the alkylpyrrole: butylpyrrole produces pyridine, and isopropylpyrrole produces 3-methylpyridine. Approximate Arrhenius equations are given for the formation of the decomposition products.

Jan 1, 1966

By Gerald E. H. Verbeek

As the number of driven concrete piles with Embedded Data Collectors increases, it has become possible to compare the widely used Beta Method to assess pile damage (using the change of pile impedance) with the so-called Measured Pile Integrity (MPI) method (a combination of two approaches using both the change of pile impedance and the change in pile pre-stress levels). After a brief introduction of both methods, this paper presents the outcome of that comparison based on data from more than 400 concrete piles driven in Florida, which brings into question the reliability of any damage assessment method based solely on the change of pile impedance (such as the Beta Method), especially to detect damage near the pile toe. Moreover the paper demonstrates the need to re-assess the damage classification used for the Beta Method as well as the use of Pile Driving Analysis (PDA) to detect pile toe damage.

Jan 1, 2011

By A. E. Hall, R. N. Taylor, J. G. Taylor

The introduction of tunnel-boring machines to South African gold mines has created problems and challenges which accompany any new technique. This paper describes the experience gained in this field, especially in the design and erection of a tunnel borer and in boring and environmental conditions.

Jan 1, 1978

By Paul M. Tyler

One by one new metals come to share the burden of modern industry. Long before the Christian era potters and glass workers employed fine and costly blue pigments that contained cobalt. Cobalt blue class has been found in the tombs of the Egyptians and in the ruins of Troy, and many of the colors used by the ancient Greeks and Romans contained cobalt. The ancients, however, were apparently unaware that the colors they used were caused by cobalt, and it was not until late in the 17th century that the existence of the element was recognized, Writers in the Middle Ages referred to "cobalos" as an evil spirit that haunted mines and caused trouble to the miners. Subsequently the German worms "Kobold," meaning goblin, came to be applied to any baffling mineral and particularly to minerals that resembled ores but failed to yield metal when smelted. Even to-day there is something of an air of mystery about cobalt, and a medieval cloak of secrecy still surrounds many of the metallurgical processes employed in its production. "Zaffre" was mentioned about the middle of the sixteenth century by Biringuccio, and in 1735 the metal war, first prepared by G. Brandt. To preparation of cobalt compounds, however, must have been carried on in at least a small way ever since the opening of the silver-cobalt deposits of Schneeberg in 1470. By 1790 there were 25 works engaged in the industry, rust of them located in Saxony, but the total output of these works probably did not exceed 300 tone of cobalt annually, mostly in the fore of smalt. The smalt which contained approximately 6 per cent cobalt was sold in Venice in 1520 at about 16 cents a pound. A few refineries in Holland supplied the Irish linen trade, contributed a farce amount to the Dutch linen industries, and alto provided smaller quantities for the manufactuer of litmus in Holland. A complete description of the early [histor,] of the cobalt industry in Saxony, is given by Mickle in the Deport of the Bureau of Mines of Ontario, vol. 19, 1913, pt. 2, pp. 234-251.

Jan 1, 1930

By Roney Eduardo Lino

As ocorrências recentes de terremotos em diversos países têm incentivado o desenvolvimento de vergalhão com características sísmicas, ou seja, que apresente elevada resistência mecânica sem que a ductilidade seja deteriorada. Este trabalho propôs uma abordagem investigativa dos principais fenômenos metalúrgicos atuantes no processo de laminação a quente de vergalhão em rolo Ø20 mm. Foi utilizado um modelo matemático de evolução microestutural com equações capazes de prever a quantidade de elementos microligantes ao longo do processo, a cinética de precipitação e o comportamento do tamanho de grão austenítico durante todo o tempo de laminação. Os resultados industriais de microestrutura e propriedades mecânicas convergiram com os resultados previstos pelo modelo. Com combinação do modelo matemático com testes industriais foi possível obter vergalhão com limite de escoamento superior a 600 MPa e alongamento de 15 %.

Oct 30, 2017

By Robert H. Merrill

This report contains a summary of the various studies made to determine the structural design of the production mine area of the Oil-Shale mine, Rifle, Colo. Prior to this investigation, it had been determined from a study of the geology, the structure of the deposit, and mining costs that the deposit should be mined by open stoping. The problem remained to determine the maximum safe roof span, the optimum extraction ratio, and the size of the pillars. These factors were determined from a study of the geologic structure of the deposit, the physical properties of the oil shale, and the magnitude and distribution of the stress around proposed underground openings. The latter was determined from both theoretical calculations and model studies. Safe roof spans, pillar sizes, pillar contours, and optimum extraction ratios were calculated from elastic theory and the physical properties of the mine rock. Safe roof spans, pillar sizes; and time effects were determined by Wright and Bucky by testing mine models in a centrifuge. The models were made from rock specimens taken from the proposed mine roof and pillars. The results from both studies agreed.

Jan 1, 1954

By J. Szekely, S. Rhee

"A mathematical formulation has been presented to describe heat and fluid flow phenomena in CVD operations. In the statement of the problem, which included consideration of plasma enhanced CVD systems, emphasis was placed on identifying the parameters which play a key role in determining the rate and the spatial uniformity of the deposition process. This was done both through the appropriate dimensionless groups and by presenting an extensive set of computed results. The main conclusions that may be drawn from this work are that the deposition rate will be inherently non-uniform for atmospheric CVD systems; this may be somewhat ameliorated by inclining the susceptor or changing the vessel contours. Operation at greatly redeced pressures and for PECVD systems will give a much more spatially uniform deposition rate.1. INTRODUCTIONIn recent years, there has been a growing interest in chemical vapor deposition techniques for the preparation of thin films for semiconductor, photovoltaic applications and for coatings in general, as evidenced by numerous journal articles and symposium proceedings devoted to this topic (1-6). An interesting variant of this technique is to perform the deposition in a plasma or glow discharge at low pressures because this technology obviates the need for the thermal decomposition of the precursor at the substrate surface and permits operation at greatly reduced temperatures (7-10).By far, the largest portion of the reported work dealing with both these aspects of the technology has been concerned with the characterization of the deposit, quite properly so. However, in more recent times it has been realized that the transport aspects of these processes are also deserving of attention because the understanding of heat flow, fluid flow and diffusional phenomena may provide the key to the solution of problems associated with obtaining uniform deposits and the proper scaling of laboratory measurements in order to design industrial CVD systems."

Jan 1, 1986

By R. Lowery

TODAY, man uses, at will, the land, the water, and the air to transport himself and his goods everywhere across the face of the world. He no longer thinks with wonder of the magic of conquering these elements - he takes his mastery of them for granted. He is, however, constantly striving to squeeze more and more efficiency from each mode of transport. Man's first method of transporting himself and his goods was, obviously, himself; then he acquired his first beast of burden - woman. Most other two-legged female animals carried their young around clinging to their fur. Human mothers were, generally speaking, furless and their offspring less 'Prehensile, and so slings and other trappings were invented to carry young children. Man's inventive genius soon adopted these devices for carrying other burdens, and for countless centuries woman carried all in order that man could walk unencumbered except by his weapons. Later other ?beasts of burden were trained and used, including dogs, horses, oxen, camels, etc. Man also discovered quite early that he could drag along the ground more than he could carry on his back.

Jan 1, 1956

By H. E. Mills

THE local auditorium of a little Alabama mining town was crowded with expectant men, women and children, as the bulletin board had announced the addition of visiting entertainers to supplement the local talent and motion pictures which usually made up the program of the regular monthly safety meeting. In the audience, near the stage, sat a group of bright-faced boys in boy scout uniforms, discussing the picture just completed. As the lights flashed on a crash and scream was heard from the outside, a shrill whistle and word of command from the scoutmaster, and five of the scouts ran out of the hall, while the mine super-intendent stepped on the stage and requested everyone to keep their seats. The scouts returned, three of them carrying a limp figure in their arms, while the other two cleared the doorway and aisle of excited spectators. They marched to the stage and, placing the apparently badly-injured boy on the floor, proceeded to give an expert demonstration of first aid to the injured. The scoutmaster then explained to the audience that the whole affair had been arranged for their benefit, and invited the local first-aid men to come up on the stage to examine and criticize the boys' work. This gave an opening for several talks on the value of first-aid training and accident prevention, which is the main object of the monthly meetings. This demonstration was given by the first-aid team of Troop One, and the entertainment was provided by members of Troop One and Twenty-eight of the Bir-mingham Scout Council, organized by the writer for the purpose of promoting interest in the welfare and safety meetings in the mining villages of the State. During the past year they have visited a number of such meet-ings and presented programs similar to the one men-tioned above. However, in order to assure a good attendance, entertainment features must also be pro-vided, and the serious part of the evening program was interspersed with excellent vocal and instrumental mu-sic, dancing and novelty acrobatic acts furnished by the visiting scouts. In addition to the numerous first-aid teams of the Birmingham Council, there are hundreds of scouts scat-tered throughout the mining district whose knowledge of first aid, safety first, life-saving, personal health and public health are a constant source of protection to their community. All of these subjects are covered by merit badge pamphlets and are required of an eagle scout.

Jan 2, 1927

By Joseph J. Wallace

1. The Pittsburgh is the most important bed in Washington County from the standpoint of present production and recoverable reserves. 2. Known measured and indicated reserves in all beds, based on a minimum thickness of 14 inches and 1,800 short tons per acre-foot of coal in place, are estimated at 4,181 million short tons as of January 1, 1954. Of this total, 4,132 million short tons is in beds 28 inches and more thick. Areas in some beds were omitted from the estimate because available data relative to the bed characteristics are too meager for making an estimate that conforms with the definitions of measured and indicated coal adopted for this study. Should future drilling or development prove reserves in these areas, such reserves should be added to the total estimated reserves.

Jan 1, 1955

By Georges Verly

The estimation of local recoveries is an important issue in a selective mining operation. Two techniques, probability kriging and multigaussian kriging, are applied to estimate local recoveries at Jerritt Canyon. The pros and cons of each method are discussed in light of the results. Both methods provide simple and satisfactory solutions to the problem of estimating local recoveries. Consequently, they can be useful tools to work with in a selective mining operation.

Jan 1, 1984

By G. W. Birge

This report describes the carbonizing properties of the principal coal beds of McDowell County, W. Va. Coals from 14 coal beds were selected for study: Upper Cedar Grove, Middle Cedar Grove, Lower Cedar Grove, Eagle, Douglas, Iaeger, Sewell, Welch, Beckley, Fire Creek and Pocahontas Nos. 3, 4, 5, and 9. Selection was based upon estimated minable reserves. McDowell County coals rank either as high-volatile A, medium-volatile, or low-volatile bituminous coal, and this variation in rank is reflected in the wide diversity of the carbonization properties of the coals. All coals tested were either satisfactory as mined or could be upgraded to meet present chemical standards for metallurgical coke; the coals produced strong coke, as determined by ASTM shatter and tumbler tests.

Jan 1, 1958

By L Lorenzen

The selection of samples for metallurgical test work is generally focused on providing geologically representative samples. One of the major problems experienced with metallurgical test work using drill hole data, is the small sample sets selected for metallurgical testing. Major process and financial decisions are being made from results obtained using snapshot samples. Snapshot samples means that samples are basically selected only by grade and spatial location with the assumption that the rest of the orebody or portion of orebody is similar and will respond metallurgically the same way – ie the assumption is that the mineralogy and lithology are basically the same as the test sample. From the test work, algorithms were usually developed and used to describe throughput and recovery using some explanatory variables including grade (mineral chemistry) and ore hardness. These algorithms were then used in the recovery models to determine tonnes produced and plant throughput. However, the metallurgical parameters are a function of many geological factors including grade, lithology, alteration, mineralogy, spatial relationships and SG. In previous years, the limited mineralogical information available was deemed enough for the metallurgist to make decisions as to how many samples are needed to evaluate the metallurgical performance of the ore during processing, and subsequently the basis for the plant design. If the orebody is consistent and not complex or refractory (thus, relative simple lithology), then only spatial and grade samples will be needed to evaluate the throughput and recovery, so limited mineralogical information may be acceptable. There is now, however, an increasing realisation that the mineralogy and geology change, as do the metallurgical characteristics of the orebody, so limited samples may not be sufficient for effective metallurgical test work.It is the purpose of this paper to discuss the effect correct mineralogical information has on the subsequent metallurgical test work program and process selection using a case study. Factors such as type of rock, rainfall and topography are thought to influence the minerals that ultimately form in various orebodies, with the result that different orebodies often react differently during metallurgical test work programs. It is therefore important to obtain accurate mineralogical and elemental deportment data, which will also indicate where the valuable metal containing minerals are located within the orebody. The better you plan and execute your metallurgical test work program during the early phases, the more accurate the decision-making process will be during the selection phase. Improved integration between geology and metallurgy data gathering (geometallurgy) during early phases will result in more accurate predictions with regard to throughput and recovery during modelling and process. Equipment selection will be considerably simpler in later phases with early planning, with improved mine and process scheduling and subsequent net present value (NPV).

Sep 5, 2011

By S. Utili

"The optimal profile of a rock slope under given geometry constraint is investigated by means of the upper bound method of limit analysis. The optimal condition corresponds to maximizing stability factor. It is assumed that rock failure condition is suitably described by the Hoek-Brown criterion. Genetic algorithm is applied for locating the optimal profile. The optimal profiles turn out to be concave profiles but there are heaps around the toes of the slopes. Compared with plane profiles, the percentage of increase in stability factor can reach up to nearly 50%. The key geometry parameters of the optimal profiles are provided for practical use. The new upper bound formulation is capable of computing the stability factors of slopes of any shape, thus the stability status of a slope under man-made excavation can be monitored during the whole construction period.INTRODUCTIONIn mining industry, man-made slopes are excavated to create working surfaces. It is important to optimize the slope profile in order to maximize slope stability under certain geometry constraint. For instance, when the height and width of an excavation are assigned, a plane profile AC (see in Fig. 1) is widely applied in engineering practice, but it has been proved not the best one in terms of safety (Utili & Nova, 2007; Cala, 2007). A vertical profile ABC is the one with least stability. Thus, it can be deduced that there is a profile within the domain of the rectangle ABCD providing the highest stability. Cala (2007) compared the difference of convex and concave profiles in stability using strength reduction technique. According to Cala (2007), circular concave slopes can increase the maximum slope inclination under given factor of safety. Besides, based on upper bound theory of limit analysis, Utili & Nova (2007) assumed a logarithmic spiral profile to prove it is more stable than a plane profile in terms of the stability factor. Although the above studies attempted to seek the best circular or logarithmic spiral profiles, none of them considered the arbitrary shape of the optimal profile and its contribution to enhance slope stability."

Jan 1, 2015

Rossiter Worthington Raymond, Ph.D., LL. D-1840 to 1918.-Dr. Rossiter W. Raymond, Past President, Honorary Member and Secretary Emeritus, died suddenly of heart failure at his home, 123 Henry'St., Brooklyn, N. Y., on the evening of Tuesday, Dec. 31, 1918. He was one of the founders of the Institute and its second President. A Memorial 'Service will be held on Monday afternoon, Feb. 17. James Douglas.- The Institute suffered a second very severe loss by the death of Dr. James Douglas, Honorary Member, Past President (having served as President for two years), and in three separate respects the greatest benefactor of the Institute: first, in raising funds by volun¬tary subscription and his own personal gifts to pay the Institute's share of the money owed on the land on which the Engineering Societies Build¬ing now stands; second, as original donor to Engineering Societies Library; and third, by his bequest of $100,000 for the maintenance of the library of the American Institute of Mining Engineers. A resolution regarding the death of Dr. Douglas was passed by the Board of Directors and at the meeting of the Institute on Sept. 4, 1918, in Colorado, at which time a memorial service was held in the thea¬ter of the Hotel Broadmoor, attended by about 400 members and guests. A copy of the resolution was prepared and sent to the family. A bronze tablet is now being prepared and will be placed in the Members' Room and unveiled at the February meeting. A biography and portrait of Dr. Douglas was published in the September, 1918, Bulletin. There is also placed in the Engineering Societies Library an oil portrait of Dr. Douglas which had his own approval and was presented by him. American Institute of Metals.--During the Spring of the year, plans were completed with the American Institute of Metals whereby this society became the Institute of Metals Division of the American Insti¬tute of Mining Engineers. This body was a dignified aggregation of metallurgists which had been in existence for about 11 years. A bronze tablet commemorating the American Institute of Metals is now being placed in the Members' Room of the Institute, and during the year 1919 the Bulletin will bear the following title: "Bulletin of the American Institute of Mining Engineers, with which is consolidated the American Institute of Metals." Visits to Local Sections.-During the year President Jennings made visits to six of the Local Sections, on three of which occasions he was accompanied by the First Vice-president and the Secretary. First Vice-president Goodale made five visitations and the Secretary made eight.

Jan 1, 1923

By D. Milne, G. Snell

"A new method to predict stope hangingwall failure in underground excavations is proposed. This method compares movement rate for stope hangingwalls, determined from changes in strain or deformation, with changing opening geometry. This geometry is represented by the effective radius factor (ERF), a measure of relative distance to supporting abutments from an opening surface point. This strain-ERF (SERF) approach is applied to an instrumentation program for Brunswick mine near Bathurst, New Brunswick. The SERF method for this case study predicted failure at an ERF of 13.9 m and hangingwall failure actually occurred at an approximate ERF of 12.4 m.RÉSUMÉ Cet article propose une nouvelle méthode permettant de prévoir la rupture de l’éponte supérieure des chambres d’abattage dans les excavations souterraines. Cette méthode compare la vitesse de mouvement des épontes supérieures des chambres d’abattage, déterminée à partir des changements aux niveaux des contraintes ou de la déformation, à la géométrie variable de l’ouverture au jour. Cette géométrie est représentée par le facteur du rayon effectif (ERF, de l’anglais Effective Radius Factor), une mesure de la distance relative jusqu’aux appuis latéraux de soutènement à partir d’un point de la surface d’ouverture au jour. Cette approche contraintes-ERF (SERF, de l’anglais strain-ERF) est appliquée à un programme d’instrumentation pour la mine Brunswick située près de Bathurst, dans le Nouveau-Brunswick. Pour cette étude de cas, la méthode SERF prévoyait une rupture à un ERF de 13,9 mètres (m); la rupture de l’éponte supérieure s’est effectivement produite à un ERF d’environ 12,4 m.INTRODUCTIONUnderground stope design can be improved with the installation of field instrumentation. The most commonly used instrumentation for monitoring rock mass behaviour around open stopes is extensometers. The y-axis of Figure 1 represents how the changing rate of movement, measured using either displacement- or stress-type instruments, can be observed over time. The magnitude of movement measured by extensometers can give an approximation of the load on installed support (Milne, Pakalnis, & Lunder, 1996) and a changing rate of movement can indicate approaching instability."

Jan 1, 2018

By T Rohde, P Defferrard

In 2010 a store and release cover (the cover) was constructed on the south waste rock dump (SWRD) at Century mine. This also included aerial seeding of province native trees and shrub seeds. The purpose of the cover is to reduce percolation into the potentially acid-forming (PAF) waste rock by maintaining a compacted reduced permeability layer (RPL) at near-saturated conditions. This is achieved by overlaying the RPL with a 1.5 to 2 m thickness of soil-mulch. The soil-mulch has a hummocky final surface that captures rainfall, so it does not runoff, allowing it in part to infiltrate, with excess water removed by evaporation and transpiration. The RPL is the trafficked surface of the SWRD.The unsaturated behaviour of the cover is being monitored by instrumentation including volumetric water content and matric suction sensors and a weather station capable of estimating evapotranspiration. The instrumentation allows for direct measurement of infiltration into the cover, storage of rainfall, percolation through the base of the cover and in situ soil water characteristic curves (SWCC).The key functions used to describe the unsaturated behaviour of the cover materials is the SWCC and the unsaturated hydraulic conductivity function. The SWCC is a plot of soil water versus soil suction. It provides the loci of moisture states of a soil from the saturated to the dry state.The paper presents the results of five years of monitoring. It shows that total infiltration into the top of the SWRD was about 1.6 – 3.7% of cumulative rainfall over five years, with most of the infiltration going into storage within the cover. Runoff from the top of the dump is not allowed therefore, the remaining 95% of the total rainfall was lost to evaporation or as lateral flow when infiltration reached the RPL. The paper presents some simple analyses of the wetting by rainfall infiltration of the cover, leading to breakthrough at the base. Field data are used to support the analyses.Presentation of the SWRD water balance is also included in the paper using SVFLUX™GE which is a finite element model that simulates water transport through a saturated or unsaturated medium.CITATION:Defferrard, P and Rohde, T, 2018. Five years of cover performance monitoring and modelling for a store and release cover at Century Mine, in Proceedings Mine Waste and Tailings Stewardship Conference 2018, pp 179–189 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Jul 23, 2018

By R. P. Singh

A mine fire model gallery has been designed and constructed on the premises of the Central Mining Research Institute, Dhanbad, India to perform systematic in-depth studies on various aspects of mine fires. The gallery is 65.5 m long and 5.86 m2in cross-section and it is divided into firing and non-firing zones. It is equipped with a computer-aided online telemonitoring system that has 130 sensors, two data loggers and computer peripherals for continuous recording of various fire parameters. A fan to generate airflow through the gallery has been installed at its end. Two sliding doors and one rolling shutter were also provided for sealing and regulation of airflow. Two sets of experiments have been carried out in the model gallery maintaining air velocity of 1 and 1.5 m/s through it. In the experiments, the inner sides of the firing zone, 22 m in length, were lined with a thin layer (8?10 cm thick) of coal slabs. Two fire suppression techniques viz. flushing of liquid nitrogen (LN2) and infusion of high pressure high stability (HPHS) nitrogen foam were tried to quantify their effectiveness under dynamic fire conditions. The paper addresses important design features of the gallery, its instrumentation system, the experimental procedure adopted and important findings from the experiments. It has been observed that the intensity of the fire was very high after one hour of its initiation and continued for 3?4 hours. During the period, frequent backlash with smoke and flame was noticed. The efficacy of the fire suppression techniques has been assessed interms of reduction in temperature, generation rate of CO2and CO, and heat release rate. The study reveals that high pressure high stability (HPHS) nitrogen foam is more effective in controlling open fires than liquid nitrogen is. Keywords: Model gallery, telemonitoring system, velocity, temperature, pressure, gas concentration, intensity, liquid nitrogen, high pressure high stability nitrogen foam.

Jan 1, 2004

By John S. Pack

The last 25 years have seen rapid expansion in the use of helical screw pile foundations and tiebacks for new and retrofit construction of buildings and earth retention structures. An estimated $100 million was spent in 2002 on helical foundations and tiebacks in the United States alone. While design information is available in the literature, information regarding quality control, inspection and performance monitoring is lacking. Recognition of at least one manufacturer's helical foundation material by the Uniform Building Code, Standard Building Code, and BOCA (all three codes now combined into the ICC International Building Code) has given added urgency to the dissemination of reliable and practical quality control, inspection and performance monitoring procedures. This paper describes a set of such procedures that have been followed for 17 years by engineers experienced in the industry who have directly installed or been involved in the installation of over 140,000 helical foundations and tiebacks in divers soil conditions for various types of structures, including earth retention structures. Topics covered include design responsibility, building code listings and requirements, manufacturer ISO certification, manufacturing process, material and installation specifications, installation contractor certification, field placement, installation procedures, field inspection, building code inspection and performance monitoring. The paper concludes with a step by step example of practical quality control, inspection and performance monitoring procedures on a typical helical foundation project.

Jan 1, 2003

By A Fowler

The unpredictability of the location, grade and width of narrow-vein deposits presents difficulties for mine geologists and engineers attempting to estimate, schedule, forecast and mine their deposit profitably. This unpredictability stems not only from the grade distribution within a vein, but also the irregularity of vein geometry in three-dimensional (3D) space. Traditional deterministic methods of modelling vein geometry do not account for the inherent variability of the veins, resulting in significant errors when using limited drill hole information. This paper presents a probabilistic method of modelling narrow-vein deposits using sequential gaussian simulation (SGS), which can quantify this variability and improve production forecasts. Vein geometry, thickness and grade are simulated to provide a number of different equi-probable realisations that each honour the drill hole and face sample input statistics. An example is presented from the Augusta narrow-vein Au-Sb mine in central Victoria, where the simulation results are validated against the input data and survey pick-ups of the veins along ore drives.

Aug 22, 2011