Search Documents

By John M. Dale

Now that the price of sulfur has reached unexpected high levels, it is little wonder that sulfur from surface ores is again receiving attention. In most instances, it is advantageous for an ore to be at or near the surface. However, it is a distinct disadvantage for sulfur ore to be close to the surface because it precludes the use of the Frasch process. The Frasch process depends on the presence of at least 180 m of uniform overburden to allow pressure injection of superheated water into the sulfur-bearing formation to melt the sulfur. In the Frasch process, sulfur separates cleanly from the gangue underground and comes to the surface in a very pure form. Surface sulfur deposits, particularly those in the Western Hemisphere, exist largely due to volcanic activity, and sulfur separation from the gangue is a formidable technical problem. None of the surface deposits are large compared to some of the Frasch deposits, but at the present sulfur price, they are certainly of economic importance. From the turn of the century until 1975, the price of sulfur was for the most part $18-$28/t. However, with the price of sulfur now over $154/t, there are a variety of technical alternatives to consider for sulfur surface ore separation that may not have been economically attractive a few years ago.

Jan 9, 1981

By O. Leuangthong, M. Nowak

"The impact of high-grade data on resource estimation has been a longstanding topic of interest in the mining industry. Concerns related to possible over-estimation of resources in such cases have led many investigators to develop possible solutions to limit the influence of highgrade data. It is interesting to note that the risk associated with including high-grade data in estimation appears to be one of the most broadly appreciated concepts understood by the general public, and not only professionals in the resource modelling sector. Many consider grade capping or cutting as the primary approach to dealing with high-grade data; however, other methods and potentially better solutions have been proposed for different stages throughout the resource modelling workflow.This paper reviews the various methods that geomodellers have used to mitigate the impact of high-grade data on resource estimation. In particular, the methods are organized into three categories depending on the stage of the estimation workflow when they may be invoked: (1) domain determination; (2) grade capping; and (3) estimation methods and implementation. It will be emphasized in this paper that any treatment of high-grade data should not lead to undue lowering of the estimated grades, and that limiting the influence of high grades by grade capping should be considered as a last resort. A much better approach is related to domain design or invoking a proper estimation methodology. An example data-set from a gold deposit in Ontario, Canada is used to illustrate the impact of controlling high-grade data in each phase of a study. We note that the case study is by no means comprehensive; it is used to illustrate the place of each method and the manner in which it is possible to mitigate the impact of high-grade data at various stages in resource estimation."

Jan 1, 2015

By Jason J. Crowder

Presentation Outline ? Introduction ? Costs of ground support and rehabilitation ? Why post-failure rock mass properties are necessary ? The Rock Mechanics Problem ? Present State of Modelling and Instrumentation in Mining ? Case Study Background ??Williams Mine ? Deriving Parameters for Modelling from Instrumentation ? Results from Case Study ??Back Analyses ? Discussion of Research Impact t Summary

May 1, 2006

By M Stewart

In January 1994, Macraes Mining Company started a new phase of exploration to find additional resources along strike and down dip of identified resources for a mill that was being expanded from 2.1 Mtpa to 3.2 Mtpa. At 30th June 1997 a total of 456,784 m in 3,627 holes had been drilled at the Macraes Gold Project with approximately 325,000 m in 2,100 holes drilled in the latest phase of exploration. This necessitated the construction of resource estimates on a more frequent basis and resulted in the formation of a resource modelling team, assisted by Snowden of Perth. Since April 1995, 14 separate resource estimates have been completed. At Macraes, resource estimates are built using Medsystem/Minesight software. The geological interpretation is converted into a set of three dimensional wireframed solid models which are used to code drillhole composites and blocks in a block model. The interpolation method of indicator kriging is used to interpolate grade into the blocks. Classification into measured, indicated and inferred categories is on the basis of geological confidence and drill spacing. The resource estimate is reconciled against grade control polygonal estimates on a bench by bench basis and on a monthly basis. Grade control estimates are reconciled monthly to mill production. For the period 30 June 1995 to 30 June 1997, the resource estimates have under predicted tonnes by 4% and grade by 1% to under predict ounces by 5% at a 0.5g/t cut off. At ROM sulphide cutoff grade, the models have over predicted tonnes by 5%, under predicted grade by 5% to over predict ounces by 1%.

Jan 1, 1997

By Mohab Sabry

Pile foundations are used extensively around the world to support both inland and offshore structures, including important structures such as nuclear plants and oil drilling platforms. The limit of the pile depth is currently predicted during the pile deriving process, given no chance for the designer to predict accurately the capacity of these piles prior installation. Furthermore, after pile installation, designer may not be able to modify the pile group design by increasing the number of piles and or changing the geometry of the pile group. This paper presents a numerical model for the case of single piles driven in homogenous sand using finite element technique and the theory of cavity expansion. The model is capable of simulating all the construction stages of concrete piles up to the maximum depth, which can be driven in sand and accordingly the capacity, which can be attained by these piles. The program "PLAXIS" is used to perform the proposed analysis. This model simulates the process of pile driving in terms of the changes in the earth pressure and the overconsolidation ratio acting along the pile's shaft. Based on the results of the present investigation, these depths can be predicted based on the pile geometry and the sand properties. Charts are given to provide these depths for given pile/soil conditions.

Jan 1, 2006

By Lennart Mukka

The Kiruna Mine in Sweden currently has three ventilation systems. The first two (a new and old system) serve the production areas. The third system is used for the facilities on the former main haulage level 775. That area includes offices and workshops for load haul dumpers (LHD) and drill rigs. The third ventilation system also covers the crushing and haulage on level 1045. At the present time, the total airflow for the mine is 1,600 m3/sec(3.4 million cfm). The current system serves the levels above the 775 level. The new one is for the levels between 775 and 1,085 m (2,540 and 3,560 ft), which are needed for the new ore body. When all of the production is below level 775, the old ventilation system will be closed down.

Jan 1, 2002

By Donald F. Reed

In the Coastal Plain sedimentaries of northeastern Mississippi, high-alumina clays and kaolins, which are bauxitized locally to varying degrees, are found in many places along the contact between the Midway (Paleocene) and the Wilcox (Eocene) series. The trace of the contact extends from Tippah County, on the Tennessee border, south to Winston County, thence southeast to Lauderdale County, and into Alabama. Its length within Mississippi, disregarding sinuosities, is 185 miles (fig. 1). Commercial production of bauxite from the region has amounted to about 400 tons, shipped from one outcrop in Komper County. In December 1941 and January 1942, the Bureau of Mines and the Federal Geological Survey made a reconnaissance survey of the contact zone and selected the most promising areas for further study. In 1942, four areas in Benton, Union, and Pontotoc Counties were investigated by auger and rotary core drilling, and in 194, core drilling was done on five areas in Kemper, Noxubee, and Winston Counties. The present report records the work done by the. Bureau of Mines and the factual data obtained from the investigations of the nine areas in the two projects.

Jan 1, 1952

By T. P. Mucho

Strata behavior and support performance were evaluated in a longwall tailgate test area at the Eagle Nest Mine near Van, WV. The mine operates in the Eagle coalbed which ranges in height from 4 to 6 ft (1.2 to 1.8 m) on the mine property. Rugged topography results in rapid changes in overburden which ranges from 200 to 1200 ft (61 to 366 m). The immediate roof at this mine transitions from sandstone to shale. In some areas the sandstone appears to be massive while in many locations it is highly laminated, fossilized, and interspersed with coal streaks. Horizontal stress levels appear to be sufficient to create instabilities in the roof in some locations, especially where the roof is thinly laminated. Traditionally, hardwood cribs have been used at the mine to provide secondary support for longwall tailgates; Strata Products' Hercules cribs are installed on 8 ft (2.4 m) centers staggered left and right in the tailgate entry. In a 250 ft (75 m) tailgate test area, however, cable bolts were installed in lieu of cribs. The bolts were 12 ft (3.6 m) long tensionable cables anchored with 5 ft (1.5 m) of resin. Four cables were installed across the entry and rows were spaced on 6 ft (1.8 m) centers. Primary roof support was maintained in the vicinity of the test area using 42 in (1.1 m), grade 60, No. 6 (19 mm diameter) resin bolts installed on 4 ft (1.2 m) centers through T-2 channels. The cable test area was located under a stream valley in an area of relatively shallow overburden. Strata instabilities consistently had been associated with the stream valley in both the Eagle and the overlying Powellton coalbeds. In an effort to further expose the cables to the most difficult stress conditions available at the time of the test, the specific site chosen was directly beneath a barrier pillar remaining in the upper Powellton mine (approximately 150 ft (45 m) of interburden separates the two coalbeds).

Jan 1, 1996

By T. Egleston

The materials containing copper which are refined in the United Statrs, are, for the most part, the natiye noppers of Lake Superior. IJntil quite recently but little pig copper Was made for sale, and that came principally from the pure sulphorous ores of New England and the Sonth, and was generally sdd to reSneries not far from the ore filrnaceu. A stnall aiuoiint found its way into the'niarket which was produced either as the by-product of the treatment of gold and silver ores, or as the result of the treatment of impure copper ores; but both these grades, on account of the impurities they contained, were loolced on with stlspicion, and were not sought for. A11 the grtlGis of pig coppcr are sold by the unit of oopper contents, a great redtiction being made in the price when impurities are present. There are at the present time only three works which treat native copper, the two of the Detroit and Lake Superior copper Company, and the works of C:G. Hussey & Co., in Pittsburgh. There are a few works ivhich smelt sulphuroris ores and refine their pig; bo sides these t1le1-e arc a few siuall works where gig copper is refined uuly. Some of these purcIlase blscir copper, refine scrap, or simply refine such grades of ingot copper as are found in the market, but nlostly that from Lake Superior, for the purpose of getting it into swh shapes that can be handled cpmtriercially to advantage, such as in making large plates or high grades of wire fir electrical purposes. A nomher of such works are situated in the Xaugaturk Vatley aud elsewhcre in New England. The recent discoveryof vnlt~sblc ores in Ariarona makm it probable that within a few year8 the refining of capper In the United States will make great develupments. Up to the time of the discovery of the mines on Lake Superior, only a very small quantity of native copper had ever been foond, not sufficient to justify the erection of worlrs fbr its special treatment. It had, besides, never been found in very large maweq so that the discovery of greabblocks of it presented serious difficulties, not oolp in mining it,-I- but in bringing it into a merchantable condit'ion. It seemed a very simple process to melt these large maws,

Jan 1, 1881

By Murad Y. Abu-Farsakh

This paper presents the analyses of load-transfer (t-z) behavior of twelve prestressed concrete (PSC) instrumented test piles that were driven in different locations of Louisiana. The load transfer method is an efficient and practical tool for the analysis of single driven pile to predict the ultimate load. The test piles were instrumented with vibrating wire strain gauges in order to calculate the shear transfer for different soil layers during the static load test. The static load test was performed on all the test piles after 10 to 14 days of end of driving. Empirical load-transfer models were proposed previously by different researchers (Fleming 1992, Hirayama 1990, Krasinski 2012, Bohn et al. 2017) after analyzing the instrumented test pile results. For this study, load transfer of each soil layer was measured and compared with the previously developed existing model. The stiffness parameter (M) for the hyperbolic equation was calibrated in order to best match the measurements. The good agreement of the proposed curves was then confirmed by applying them to assess the overall load-settlement curve of other pile load test results available in the literature. INTRODUCTION The load transfer mechanism (stress-strain relationship) for an axially loaded pile usually comprises of three loading mechanisms: axial deformation in the pile (z), soil skin friction along the shaft (qs), and soil end-bearing (qb). The development of soil skin friction with axial deformation is referred as the t-z curve, and the development of soil end-bearing with axial deformation is referred as the q-z curve. Figure 1 presents the load transfer mechanisms in an axially loaded pile and the corresponding spring mass models for t-z and q-z curves (API, 2002). In order to construct the load transfer curve in clay under vertical load, the axial load transfer (t-z) curve and end-bearing load transfer (q-z) for that particular soil should be assessed separately. The axial load transfer (t-z) method is probably the most widely used technique to study the problem of single axially loaded piles. Therefore, the load transfer through the shaft of the pile and are getting more and more important compared to the only the pile capacity analyses. The load transferred from shaft to the surrounding clay soil is a function of the width of the pile and the surface roughness of the pile and clay properties. The development of a representative procedure allows the assessment of the t-z curve in soil (sand and/or clay) that leads to the prediction of a nonlinear vertical load-settlement response at the pile head.

Jan 1, 2018

By R. Costantini

The author discusses the promising future of the use of pipelines for transportation of ore slurries over long distances, citing existing installations. Various criteria and factors affecting the use and size of pipelines are considered. Among the factors influencing the use of pipelines are particle size, specific gravity, abrasiveness, minimum velocities, and pumping considerations. Long-distance transportation of solids by hydraulic pipelines holds the promise of great economic benefits. Today within the confines of most mineral processing plants, the moving of solids about in slurry form by pipeline is commonplace, since the method offers great advantages when conditions are suitable. Yet, this method is surprisingly slow in being adopted on a broad scale for transportation of solids over long distances (arbitrarily the term will be applied to one over five miles long). This is especially surprising in view of the successful realization in this country within the last five years of two daring ventures in long-distance solids pipelines. A 72-mile long, 6-in. diam pipeline of the American Gilsonite Co. has been satisfactorily transporting 700 tpd of gilsonite from the mine at Bonanza, Utah, to the processing plant at Grand Junction, Colo., since April 1957. The 108-mile long 10-in. diam pipeline of the Pittsburgh Consolidation Coal Co. has been transporting about 4000 tpd of finely crushed coal from the mine at Cadiz, Ohio, to the Eastlake power plant of the Cleveland Electric Illuminating Co. on Lake Erie since January 1958. However, besides two projects in the operations of The Anaconda Co. there have been hardly any other significant solids pipeline developments in the minerals industry during the last three years. The two projects are the 14-mile long, 6-in. diam copper concentrate gravity pipeline at Anaconda's El Salvador project in Chile which has been transporting about 800 tpd since January 1959. The second is a 16-in. diam tailings pipeline at the Anaconda Reduction Works, Anaconda, Mont., designed to transport about 20,000 tpd of deslimed flotation tailings for dam building. This pipeline, which is currently undergoing tryout tests and which will be about seven miles in length, will have a maximum of three 20-in. rubber-lined centrifugal pumps in series at the starting point, each developing a maximum of 100 ft of head, to supplement gravity. It is the writer's opinion that the major reason for the hesitation in considering pipeline operations is confusion due to an inadequate understanding of the basic physical principles affecting the slurry flow process by many engineers in the industry. This in turn begets an attitude of fear and trepidation instead of confidence on the part of many management executives, which leads to a minimizing of the advantages and exaggeration of difficulties when considering the possibility of a long-distance solids pipeline. The promotion of better understanding and consequently the promotion of greater confidence in the potentials of long-distance solids pipelines when conditions are suitable is thus the main purpose of this article. To this end, after considering several examples of the possibilities for solids pipelines in the minerals field, the relative significance of the major factors affecting pulp flow, and some major aspects of slurry pumping will be discussed on a general qualitative level. Then a brief outline of the semi-empirical quantitative methods developed to date for estimating slurry flow behavior will be presented. SOME POSSIBILITIES To give an idea of the magnitude of the possible economic benefits, it should be interesting to mention briefly some of the projects currently under consideration and to suggest some likely future possibilities. At Anaconda's El Salvador Project in Chile (Fig. 1) it is eventually planned to extend the existing 14-mile pipeline by another 60 miles to bring the copper concentrates down to the coast of the Pacific Ocean. Preliminary tests indicate that the projected 6-in. pipeline will be able to transport approximately 2000 tpd of concentrates at a pulp density of 40 to

Jan 1, 1961

By Q. G. Reynolds

Keywords: Pyrometallurgy, furnace, DC, reverse polarity, dual-electrode The dual-electrode direct current (DC) arc furnace uses two graphite electrodes, one connected as cathode, and one as anode. Such an arrangement avoids some of the design difficulties associated with the anode hearth traditionally used in single electrode and twin-cathode DC furnaces, but can introduce other design and operational difficulties including deflection of the arcs toward the furnace walls. Counter-intuitively, both arc jets in a dual-electrode furnace travel from the electrode down to the bath surface, despite carrying electric current in opposite directions ? this is suggested in the theory of the governing equations of arc formation, and confirmed by experiments using high-speed photography. The dual-electrode arc system at small pilot-plant scale is studied using a transient magneto-hydrodynamic model capable of predicting arc deflection and interaction from first principles, and the results are compared to the behaviour of twin-cathode systems at similar power. Finally, a simple arrangement of the furnace busbars, M configuration, is shown to provide some passive protection against arc deflection.

Jan 1, 2011

By Douglas B. Silver

Super Cycle future The final topic is mining?s future. The most important questions are ?How much longer is the Super Cycle going to last? What should we expect to see going forward? How will the Super Cycle end?? Three possible scenarios follow. Scenario one: Super Cycle has peaked Kathy Casey-Kirschling is officially the first Baby Boomer. She was born Jan. 1st, 1946. If you google ?first baby boomer,? she?s the one that shows up. A Baby Boomer is anybody born between 1946 and 1964. In the United States, it represents about a quarter of the population ? approximately 76 million people. The Baby Boomer generation is going to change the economics of the world because there are so many in the generation. A review of spending patterns indicates that the largest amount of discretionary spending occurs between the ages of 49 and 52. Retired people tend to live on fixed incomes so they have less discretionary income. They also tend to downsize their house, which may contribute to the housing glut and the need for a lot less metal. Therefore, the upcoming retirement of the Baby Boomer generation could result in a massive shift in economic spending resulting in the peaking of the Super Cycle. Figure 1 is an index graph from the Toronto Stock Exchange (TSX). The index has recently peaked. A lot of people see that as a sign that bad things coming our way. A careful review of different commodity prices also suggest that the peak has occurred and it does not seem to matter which commodity prices are considered. Copper prices have seen a peak as have nickel prices. Nickel and molybdenum displayed the same trend with a peak in 2005 as did zinc. Uranium, which has single-handedly tried to behave like the dot com craze, has also peaked.

Jan 1, 2008

By L. M. Dyer

Various attempts have been made to build leadership and management expertise with little success. There are numerous reasons these attempts have failed. Three reasons, along with suggested solutions, will be explored: 1) lack of ownership of the development process by those affected; 2) lack of congruence of the development process used and the business strategies of the organization; and 3) a comprehensive development process. We will discuss a development model applied inside a smelter and refining complex over one year involving all levels of management. The process was credited with helping to substantially reduce cost and enable breakthroughs in production, quality and safety results.

Jan 1, 2000

By Edmond Chin

The land mass of the Asia and Pacific region comprises 11 million square miles or about 15% of the total Earth's land area. The bulk of the region is contained on the Asian continental land mass. Australia, the world's largest island or the world's smallest continent, alone is almost as large as the continental United States. The islands of New Zealand, New Guinea, Borneo, Sumatra, and Honshu are among the largest in the world. Collectively, they constitute a land area of 1.1 million square miles or an area about one-fourth the size of the United States. The countries in the Asia and Pacific region represent some of the most vibrant economies in the world. Japan is undisputed as one of the world's leaders in manufacturing and commerce. Hong Kong and Singapore are significant both as entrepôt and banking centers. The economies of Australia, the Republic of Korea, and Taiwan compare favorably to the level of the industrialized countries in western Europe. Indonesia, Malaysia, the Philippines, and Thailand have maintained strong economic growth during the past two decades. All these countries in the Asia and Pacific region collectively constitute a significant bloc as to raw materials production and consumption, as to manufacturing, and as to world trade.

Jan 1, 1992

By G. Adderley, A. Wetherelt

The problems of poor drilling in underground operations have been highlighted on many occasions. Incorrect collaring and poor angular deviation can all lead to an increased block size, dilution, over-break adding to both cost and time, while in a tunnelling operation sidewall damage and a poor percentage pull from a blasted round has similar consequences. This paper sets out to further investigate the ability of the laser scanner method of obtaining drill hole deviations and collaring errors at the face as described by Wetherelt and Williams (2006). Tests were carried out to compare measured inter-hole burdens from this method in comparison to that obtained using a total station survey. To investigate the ability of these methods to accurately determine drilling errors, a field test was carried out through an analysis of a series of pre-drilled blast holes of known inclination and direction. A time-motion study was also conducted for a varied number of holes to assess the usability of each method. In line with current research into blast vibration being undertaken at the Camborne School of Mines, 6 cut blasts were carried out to establish the effect of poor drilling on a blasts success to see whether an increased burden at the toe of a hole had an influence on vibration.

Jan 1, 2009

By M. V. Mielke, R. E. Hagen, R. L. Bennett

FINE IRON ORES, and concentrates such as those produced from taconite, must be converted to lump form by some process of agglomeration before they can be used effectively in the blast furnace or open hearth. At the present time, four major processes for agglomerating these materials are being used on a commercial scale: sintering, nodulizing, pelletizing and briquetting. IN 1945 U. S. Steel Corp. through its subsidiary the Oliver Iron Mining Div., drew up tentative plans for an agglomerating plant on the Mesabi Range which would include a nodulizing kiln and a sintering machine. The purpose of the plant was two- fold: during its initial operation it would provide data on agglomeration of high grade ore fines, and would help relieve the shortage of ore for open hearth charging. Subsequently, it would be available for agglomerating taconite concentrates. While operating on fines screened from direct ore, it was planned to develop techniques and personnel so that a workable plant would be ready to handle taconite concentrates when the time came.

Jan 1, 1954

Since the 1989 Loma Prieta Earthquake in the San Francisco Bay Area, the California Department of Transportation (CALTRANS) has accelerated seismic upgrading of their bridges. Many structures can be improved with the simple addition of hinge seat restrainers. Others require modification of column bents and superstructure to column connections. Often, footing retrofits are necessary, which require the addition of tension/compression elements (compression piling and tiedowns anchors) to resist overturning moments substantially larger than those originally used for footing design. These footing retrofits may include doweled reinforced concrete footing extensions or new pile caps which transmit forces to either driven steel or drilled concrete piles. In some cases, installation of these traditional piling elements is expensive, impractical or impossible due to: low overhead clearance, ground obstructions, high water table, noise or vibration sensitivity, or the inability to laterally expand the existing plan dimensions of the footing. In the latter case, one practical option is to attach small diameter drilled and grouted tension/compression piling elements (Pin Piles) to the existing footing. The footing may be strengthened with dowels and added concrete thickness or there may be a reduced shear span due to the installation of larger or jacketed columns. A reduction of elements is available with a Pin Pile alternative, particularly when the selection of traditional standard piles is governed by the reduced tension/uplift capacity available from the traditional elements, since Pin Piles exhibit superior uplift performance.

Jan 1, 1993

By Cristhian C. Mendoza, Renato da Cunha, Bernardo Caicedo, Max Barbosa

"Abstract This paper shows that a raft alone is not sufficiently appropriate to address the uncertainty of underlying soil variability; therefore, a piled raft system is a better option for mitigating such uncertainty. To study the variability of soil, the behavior of the Piled-Raft Foundation was analyzed with a type of self-drilling micropiles: the ""Alluvial Anker"" (common name for this pile type in Brasilia city). These micropiles have been used in the city and have the advantage that the drill pipe also serves as reinforcement. The studied parameters belong to an elastoplastic constitutive model for strain-stress analysis of soil; variability of these parameters can be intrinsic and/or epistemic. Simulations were performed for a hypothetical Piled-Raft Foundation subjected to vertical loading using the random finite element method. The average parameters of the constitutive model were obtained through laboratory tests. The simulations of the load test were compared with results of a real scale experimental test conducted exclusively for this work in the field. It is analyzed the relative importance of the variability of some geomechanical parameters and their variation with depth is considered. In addition, it is discussed a comparison between the uncertainty of the geomechanical parameters and the uncertainty of the results of the vertical loading test. Finally, this paper shows that a decrease of the safety factor may occur when taking into account the variability of the parameters.IntroductionBrasilia is located in a highly weathered residual tropical soil (lateritic & latossol on pedogenetic concepts). This soil presents high content of alumina and iron due to the lixiviation process of the upper layers. As a consequence, the cemented structure is highly unstable and it can generate strong changes of volume (i.e. collapse) due to changes in both moisture and state of stresses. Therefore, a greater understanding of the construction of Piled-Raft Foundation systems on this particular soil conditions is needed – especially because it covers more than 80% of the surface area of the Brazilian Federal District.Thereafter, this work investigates the influence of the variability of the soil parameters over the uncertainty of the Piled-Raft Foundation design. The studied parameters belong to an elastoplastic constitutive model for strain-stress analysis of soils. The simulations were performed for two hypothetical Piled-Raft Foundations subjected to vertical loading by using the stochastic finite element method. The results were compared to real load tests in Piled-Rafts with “Alluvial Anker” pile types."

Jan 1, 2014

By Y Öztas, S McKinley, T Baker

The Kisladag Mine, Turkey, is a large porphyry gold deposit which is mined by open pit methods. In operation for over ten years, Kisladag provides an excellent example of how attention to a geologic feature, namely hydrothermal alteration, became a very effective predictive geological tool for planning and operation. The alteration domains were initially used as a geological tool to assist with establishment of resource model domains and to guide delineation drilling, but they were soon recognised to be correlative to geotechnical characteristics (affecting pit slope angles) and metallurgical performance (heap leach recoveries). Recent developments in spectral processing allow the systematic quantification of complex overlapping alteration phases and have greatly improved the ability to rapidly define internally consistent alteration domains for geotechnical and geometallurgical purposes.Alteration at Kisladag comprises a central core potassic (K-feldspar-biotite) zone, a tourmaline-white mica enveloping zone, an advanced argillic lithocap on the deposit’s eastern side and an overprinting pervasive argillic zone. These alteration zones and their distribution were based initially on strictly qualitative, visual mineralogical logging of diamond drill core. With the need for more accurate and consistent identification of the alteration mineral suites, particularly the phyllosilicate phases, logging was augmented by systematic measurement of spectral data using a Terraspec instrument.Recently the Kisladag spectral database (over 85 000 readings) was reprocessed by the newly developed methodology (aiSIRIS™) that allows relative quantification of the spectrally-responsive minerals. Visualising this transformed spectral mineralogy at various mineral concentration thresholds using implicit modelling software (Leapfrog®) led to the creation of consistent mineralogical and alteration domains that are used for the definition of geotechnical and geometallurgical parameters. An implicit modelling workflow enables these domains to be easily updated as new data is collected while maintaining geological integrity of the model.CITATION:McKinley, S, Baker, T and Öztas, Y, 2017. Alteration at Kisladag gold mine, Turkey – a progressive study in geology, geotechnics and geometallurgy, in Proceedings Tenth International Mining Geology Conference 2017, pp 51–62 (The Australasian Institute of Mining and Metallurgy: Melbourne).

Sep 20, 2017