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The mineralogy of regolith material for which whole rock geochemistry has already been done can be used to better understand/rank the significance of geochemical anomalies. Case studies show that the secondary minerals of the regolith environment have quite different capacities to incorporate pathfinder and target elements, eg hematite appears to be a better host to Pb than goethite and Pb rich alunite-jarosite minerals are a better Ag host than mimetite. Thus correlations between elements in regolith material may be strongly affected by mineralogy. Understanding of the significance of a geochemical anomaly is frequently enhanced by knowledge of the weathering susceptibility of different minerals. For example, when a mineralogical sequence which does not correspond to the expected order is found (eg feldspar overlying weathered material without feldspars) it is possible that transported material is present in the profile. Such mineralogical information is particularly relevant as exploration continues into areas of thick regolith.

Jan 1, 1997

Ceremonies for the induction of four mining industry pioneers into the National Mining Hall of Fame will be held Saturday, Sept. 11, 2010 at the Charles F. Barber Pavilion of the Museum Convention Center in Leadville, CO. The 23rd Annual National Mining Hall of Fame and Museum Banquet will begin with an open house and reception at 5:30 p.m., followed by the dinner and program at 7 p.m. The four inductees are: William Wheeler Coleman who served 46 years, from 1911 to 1957, as president and chairman of the company that is now Bucyrus International of South Milwaukee, WI, a world leader in the manufacture of surface and underground mining equipment. Dr. Allen Van Heyl, Jr., an economic geologist who served with the U.S. Geological Survey for nearly 50 years beginning in 1943. He studied more of the nation?s mineral deposits than most could begin to imagine. Arthur Lakes contributed enormously to the geological and mining sciences in the western United States as a geologist, teacher, writer and artist over a period of more than four decades beginning in 1869. The Arthur Lakes Library at the Colorado School of Mines, Golden, CO, is named for him. Samuel Calvin McLanahan, through his inventive genius, changed the direction of his family?s company from that of a foundry to a leading manufacturer of minerals processing equipment to become today?s McLanahan

Jul 1, 2010

By David Dreisinger

"The leaching of base and precious metal ores and concentrates continues to progress in both laboratory study and industrial application. These developments are being driven by the need to respond to difficult ores and concentrates that are not amenable to conventional treatment. In many cases alternatives are being developed to conventional treatment (e.g. Pyrometallurgy) for technical and economic reasons.In this paper, a brief general review of some new developments in leaching will be followed by a more detailed explanation of three process developments that have either been industrially applied or are expected to be applied in a short time frame. The three processes to be reviewed in detail are the Mt. Gordon Copper Process, the Anglo American Corporation/University of British Columbia Copper Process and the PLATSOL Process. These leaching processes operate at low (90°C), medium (150°C) and high (220°C) temperature and are successful in quickly and completely extracting metal values from ores and concentrates.INTRODUCTIONThe process of leaching is widely used in hydrometallurgy to selectively recover a metal of interest from an ore or a concentrate. Leaching and by extension hydrometallurgy is well established in the recovery of copper (copper heap leach ? SX-EW), nickel (Moa Bay and Caron process), zinc (roast ? leach ? electrowin and zinc pressure leach), gold (cyanidation) and uranium (acid sulfate leach). Of course this success extends to many of the metals found in nature. Recently, the importance of hydrometallurgy appears to be increasing with hydrometallurgy viewed as an attractive alternative to both traditional mineral processing and conventional smelting/converting/refining. This increasing interest has led to intensive study and increasing application. Selected developments include:Copper ? the Mt. Gordon process and new concentrate processes such as INTEC, Activox, CESL, Dynatec, Total Pressure Oxidation, MIM Albion, BioCop, and the AAC/UBC Process.Nickel ? Voisey Bay process for hydrometallurgical treatment of Voisey Bay concentrate, HPAL processing of laterites at Murrin Murrin, Bulong and Cawse, atmospheric leaching of laterites, heap bioleaching of nickel sulfides by Titan Resources (Australia).Zinc ? establishment of zinc leach, solvent extraction and electrowinning technology for treatment of the Skorpion deposit in Namibia, new developments in atmospheric and pressure leaching, the Hydrozinc process.Gold ? development of a number of thiosulfate leaching processes for recovery of gold from refractory carbonaceous ores or concentrates."

Jan 1, 2003

By A. Singh, M. Ntlhane, V. Ross, M. Dlame

"Fine valuable particles are often lost to flotation tailings streams due to inefficient collection by air bubbles as well as passivation of surfaces by oxidation and slimes. The application of high-shear hydrodynamic cavitation devices (HCDs) to overcome this problem has already proven to be a considerable success in the industry. This paper details the results of further investigations that were undertaken at Mintek to better understand the mechanisms involved when preconditioning feed slurries in an HCD. By promoting inter-particle attrition and conditions of high shear within the reactor, cleaning of particle surfaces is enhanced as well as the formation of superfine (nano) bubbles which are believed to aid their agglomeration and subsequent collection by normal sized bubbles. In order to broaden the envelope of understanding with regard to application of the technology, rather than tailings material as investigated earlier, a Platinum Group Mineral (PGM) UG2 ore from the Bushveld Complex in South Africa was used in this study. The results of a series of batch flotation tests in a 10L Denver cell are presented, being conducted after the feed has been subjected to different methods of preconditioning. It was demonstrated that the preconditioning significantly improved the flotation kinetics of the PGMs, the optimum being obtained after around 20 passes through the reactor. This was accompanied by a much enhanced recovery-mass pull relationship and a significant improvement in the grade-recovery response. Significantly, the selectivity between the PGM and the deleterious chromite (expressed as Cr2O3) gangue more than doubled under these conditions. Modelling of the PGM data by means of the modified Kelsall model indicated that both the fast and slow floating rate constants were improved.INTRODUCTIONIt is well known that the flotation recovery of fine and ultrafine particles, typically less than 10 micron in size, is a challenge (Yoon et al., 1989; Miettenin et al., 2010). Although these particles are typically well liberated, due to their very low mass and inertia, the collision efficiency with air bubbles is low as a result of the inability of particles to penetrate the liquid streamlines around bubbles. Hence the probability of contact is often regarded as the ratedetermining step in flotation of ultrafine particles. Introducing more power into conventional flotation machines is likely to solve only part of the problem, as conventional mechanisms are effective only to a point in terms of shear and micro-turbulence. Further challenges are posed by the treatment of low-grade or oxidised tailings dump material, where valuables are passivated due to prolonged exposure to the atmosphere or slimes. Over the years, various mitigating strategies have been investigated, including the use of dissolved air flotation (Martinez-Gomez et al., 2013; Calgaroto et al., 2015), shear flocculation (Subrahmanyam and Forssberg, 1990), seed or carrier flotation (Tabosa and Rubio, 2010), sonication to clean particle surfaces (Aldrich and Feng, 1999; Newell et al., 2006), high intensity conditioning (Bulatovic and Salter, 1989; Chen et al., 1999; Tabosa and Rubio, 2010), and various electrochemical approaches such as changing Eh in order to promote formation of dixanthogen, dissolution of oxidation products by lowering the pH, activation by sulphidisation (Newell et al., 2006; Becker et al., 2014), and the use of alternative collectors."

Jan 1, 2018

By Kenneth K. Humphreys, Joseph W. Leonard, Robert L. Llewellyn, William F. Lawrence

INTRODUCTION Cleaning fine coal sizes utilizing air currents in machines as the primary separating medium is called dry concentration or pneumatic cleaning. In 1947 approximately 18 million tons (16.38 million mt) of bituminous coal were cleaned by air machines; in 1965, 25.4 million tons (23.1 14 million mt); but in 1975, only 7 million tons (6.37 million mt). Table 11-1 shows the tonnages cleaned of bituminous coal and lignite in the United States by various types of equipment from 1938-1963. Table 11-2 shows only tonnages cleaned by pneumatic methods from 1964-1975. The decrease in tonnage to approximately 7 million tons (6.3 million mt) is due to a higher moisture content in the mined coal and the greater difficulty in cleaning the coal by air. There also was a definite trend to load raw coal at the mines, especially the slack which is the most expensive to clean due to the dewatering and drying requirements. While there have not been any applications of pneumatic cleaning in the anthracite field, its use has not been fully explored. The same is true for lignite and subbituminous coals.

Jan 1, 1979

By John M. Hartman

On May 19th, 1857, an English patent was granted to E. A. Cowper for heating air or other gases under pressure by means of a regenerator inclosed in an air-tight iron case, having between the regenerator and case a lining of brick. This patent provided for heating the stoves by a separate fireplace, or by gas direct from the blast furnace. A number of forms of interior arrangement of the brickwork are shown in the drawings; also hollow poppet valves with hollow stems, and a pipe inside of the stem for circulating the water; the valve seats have coil cast in them for water circulation to keep them cool; slide valves, with snake coil cast in the discs, are shown, and the use of cold air for cooling the valves is also described. The combustion-chamber of these stoves was central, and openings mere provided at the top and bottom to get into the stoves. These Cowper stoves are all circular in section. November loth, 1865, an English patent was granted to Thomas Whitwell for regenerative stoves for heating air or gas, provided with cleaning openings at the top and bottom capable of being closed with firebrick plugs and doors. The drawings show a rectangular stove inclosed in an iron case. The interior brickwork has numerous upand-down passages through the stove, but there is no claim on the interior construction. March 3d, 1868, an English patent was granted to Charles Cochrane for a slide valve to be subjected to high heats. The disc of this valve was hollow, and had a circulation of water through it by the two hollow stems that operated it. The valve-seat was detachable and had a coil cast in it, through which water circulated. The valve and seat were placed on an incline to the body to cause the valve-disc to lie on the valve-seat. A cap was placed on the bottom of the body to get at the interior readily. January 5th, 1870, an English patent was granted to Siemens, Cowper and Cochrane for the construction of regenerators in firebrick stoves, with numerous vertical passages of sufficient size to allow a brush to pass through and clean them. These passages had slight projections on the sides to tarn the air over and over as it passed through. A claim also covered the use of horizontal passages connected at each end alternately, and the use of blasts or jets of air,

Jan 1, 1880

By Renpei Yoda

An investigation was conducted to develop columbium alloys with e1evated-temperature strengths higher than those exhibited by more common commercial columbium alloys, and attention was given to improving the oxidation resistance and ease of fabrication. Additions of carbon, aluminum, and chromium were made to some columbium-base alloys, and their effects on workability, recrystallization, oxidation resistance, and mechanical properties at elevated temperatures were explored. The additions were made to take advantage of (1) solid solution strengthening, and (2) precipitation hardening. Three alloys displayed good high-temperature properties with relatively good oxidation resistance at 1,000° C, and tensile strengths from 26,000 to 32,200 psi at 1,400° C. When the properties of these alloys were compared with those of commercial alloys, B-66 and FS-85 (1),4 the outcome was favor-able for the alloys studied in this investigation.

Jan 1, 1967

By Victor De Ysassi

THE iron mines of Spain are located on the mountain ridge forming the boundary between the, Teruel and Guadalajara provinces, called Sierra Menera. They form a property of 25 mines extending over an area of 1,677 hectares (4,140 acres) situated at a height varying from 1,200 m. (3,940 ft.) to 1,500 m. (4,920 ft.) above sea level. The deposit follows the direction north to south; huge masses of ore are being found both on the slopes and at the summit of the Sierra. The ore occurs among quartzites and magnesite limestone, in some places overlaid by quartzite 15 in. (50 ft.) thick; in some others (and this is more general) the ore is overlaid by earth and boulders of quartzite origin,; this layer is about 8 m. (26 ft.) thick. The ore beds occupy the geological horizon of the Superior Trias or Muschelkask, which are here in direct contact with the Silurian quartzites. The lime-stones have been more or less transformed. There is ample evidence to show that these mines were worked in very ancient times-objects and tools employed in mining by the ancient Romans and Arabs are to be found plentifully in old workings which extend down into the deposits. It has been estimated that more than 10,000,000 tons of ore were mined in the old days in this district and carried to the primitive forges in the vicinity where iron of much renown in Spain was extracted. Remains of more than 20 of these forges are found in the neighborhood of Sierra Menera and are usually situated near waterfalls and forests. Much investigation has been carried on for the purpose of determining the quantity of ore to be found in these mines, but no exact calculations can be made at present. When the investigation is completed it will surely be found that the deposit contains a much larger quantity than the 100,000,000 tons indicated by the present workings.

Jan 2, 1916

By W. A. Cole

This report covers the preliminary phase of an investigation of some clays and shales and other materials in North and South Dakota to determine the feasibility of lightweight -aggregate manufacture in the two States. The background of the light - weight -aggregate industry, on a national basis, and results of preliminary laboratory testing of samples of North and South Dakota clays and shales from various localities are presented herein. The countrywide search for lightweight aggregates was necessitated toward the end of the 19th century by the change in building design from thick, heavy, load- bearing walls to a framework of structural steel .beams and columns with thin walls, followed shortly by the use of reinforced concrete and structural concrete as materials for the load-supporting frame. Ordinary concrete, with sand and gravel aggregate, weighs about 150 pounds to the cubic foot. A lighter concrete was needed to relieve the dead load and make it possible to construct higher buildings or add stories to existing buildings.

Jan 1, 1954

By GEO M. FOWLER

AN appraisal of the activities of the mining geologists during 1936 clearly indicates the ever in- creasing utilization of geology in the search for ore. Few men with geo- logic training are idle at present; this is particularly true regarding recent graduates. Many have accepted employment in distant fields, such as the Philippines and South America, and greatly increased mineral production from these places reflects their activities. In North America, regions of intense mineralization formerly important are being restudied in greater de- tail and with better understanding; as a result, new mineral wealth is being found in many such districts. Much is being done by private companies and individuals, and it is to be hoped that mining companies will increasingly make available the purely scientific results of such studies by permitting their geologists to publish. On such generosity to a large extent will future advances in ore finding depend.

Jan 1, 1937

By P. Comba

The U.S. Bureau of Mines investigated a hydrochloric (HC1)-calcium fluoride (CaF2) leaching procedure to treat domestic manganese (Mn)-bearing silicate resources. The proposed process is an alternative to high-temperature and energy-intensive extractive techniques. Single-stage leaching with a stoichiometric amount of HCl and a F-Mn mole ratio of 0.2 extracted 96 pct of the Mn when the leach conditions were 50° C, 3 h, and 35 pct solids. Ninety-eight percent of the Mn was extracted during countercurrent leaching at similar conditions. A process flowsheet was developed that incorporated HC1-Cab leaching, excess leach acid utilization, fluoride (F) recycle, and Mn recovery. When the domestic manganese silicate ore was processed, 98 pct of the Mn was extracted, 99 pct of the Cab was reclaimed, and a leach residue was produced that passed the Environmental Protection Agency (EPA) Extraction Procedure (EP) Test for nonhazardous waste.

Jan 1, 2010

By Qin-yong Ma, Jing-shuang Zhang, Bo Han, Pu Yuan

In order to improve the utilization rate of blasthole and blasting effect in vertical shafts, 5 kinds of millisecond blasting model tests with three circle vertical blastholes have been conducted in various delay times with concrete as model material. The blasting effects of millisecond blasting model tests are investigated from cutting volume, cutting depth, and blasting fragmentation, then a reasonable delay time is obtained. In the middle of concrete model, there are 4 blastholes uniformly distributed in the first circle, 6 blastholes uniformly distributed in the second circle, and 10 blastholes uniformly distributed in the third circle. Each blasthole is charged with one millisecond delay electric detonator, and the rest is blocked with stemming. The depth of blastholes in the first and second circle is 180mm, which is 20mm deeper than those in the third circle. After initiation, the blasting cavity is cleaned up, then the cutting volume and cutting depth are measured. Meanwhile, the blasting fragments are gathered and have analysed by function Rosin-Rammler. The test results show that when the inner two circle blastholes initiated simultaneously and the third circle blastholes initiated with millisecond delay, the reasonable delay time is 50 ms. At this time, the cutting volume and cutting depth of blasting model are 3920 cm3 and 68 mm respectively. The fragmentation indexes of blasting fragments, X50 and X80, are 53.2 mm and 74.6 mm respectively. While when all three circle blastholes initiated with millisecond delay, the reasonable delay time is also 50 ms. At this time, the cutting volume and cutting depth of blasting model are 10705 cm3 and 118 mm respectively. The fragmentation indexes of blasting fragments, X50 and X80, are 51.0 mm and 81.7 mm respectively. The researches indicate that for millisecond blasting with multiturn blastholes, the reasonable blasting scheme is multiturn blastholes initiated in millisecond delay and the reasonable delay time is 50 ms.

Jan 1, 2015

By D. W. Horsfall

The different types of processes used in fine coal beneficiation in the Republic of South Africa are listed, together with data giving an indication of their separating efficiencies The two classes of coal, fines and ultra-fines, present in the -0,s m fraction of the run of mine coal are discussed, with special reference to their beneficiation characteristics. Using those properties, together with the data on plant efficiency, case studies are worked out to indicate the advantages and disadvantages of the different processing routes available. The paper closes with an indication of areas where research is required to enable some of the processes to be applied to a greater extent than is presently the case.

Jan 1, 1988

By P. Chris Pistorius

Calcium treatment of alumina inclusions, to convert the alumina to molten or partially molten calcium aluminates, is a well-established treatment for steel, to improve the castability of aluminium-killed steel. However, the role of magnesium in calcium-treated steel is not fully clear, nor is the origin of the several percent of magnesium oxide that is often present in calcium-treated inclusions. To study this, steel was sampled after calcium treatment at an industrial steel plant, and the inclusions identified by energy-dispersive X-ray microanalysis (EDX) on polished sections of the samples (analysing the samples in a scanning electron microscope). The predicted fraction liquid in the inclusion was estimated from the ternary alumina-magnesia-lime phase diagram. Inclusions with higher CaO contents generally had lower MgO contents, indicating that the calcium wire is not the origin of the magnesium in the inclusions; this was also confirmed by wet chemical analysis of the calcium wire. Instead, it appears that magnesium-alumina spinel inclusions form during extended ladle contact after aluminium killing and before calcium treatment. While such spinels have been stated to cause poor castability (clogging the submerged-entry nozzle), it is clear that calcium treatment successfully modifies the spinel inclusions to mixed alumina-lime-magnesia inclusions, where the magnesia content contributes substantially to liquefaction of the inclusions: for typical MgO contents of around 10%, the range of Ca:O ratios which yield liquid (or partially liquid) inclusions is extended substantially to lower Ca:O ratios.

Jan 1, 2006

By Harris RW, Wood BR

At any given time, the tidal force subjects massive regions to a spatially uniform load. The deformation of any large structure due to these forces is proportional to the elastic properties of the structure. In this aspect, the tidal force applies a load in a manner similar to that of a large-scale testing machine. Any anomalies in the measured tidal response must reflect alterations in the average elastic response of the massive structure. In the present work, tidal tilt measurements obtained in the wall of a large dam are used to infer changes in the response of the dam to applied loads. In particular, it is found that the dam response has changed by approximately 13 percent, on average, for two monitoring periods separated by 5 years. It is possible that these changes were produced by the different volumes of water in the dam for the monitoring periods. The tidal measurement technique can also be applied to monitor changes In the average structural response of large underground and surface masses relevant to coal and metal mines.

Jan 1, 1992

By H. H. Schrenk

One phase of Bureau of Mines work in health and safety is promotion of the use of safe, satisfactory, and reliable respiratory protective devices. To insure that such devices will be. available, the Bureau has established schedules of minimum requirements for oxygen breathing apparatus,3/ gas masks,/ supplied-air respirators (hose masks, air-line, respirators, and abrasive blasting helmets, hoods, or masks),5/ and dispersoid (dust, fume, and mist)

Jan 1, 1943

By A. F. Colombo

In an effort to maintain an adequate supply of iron to meet national economic and strategic needs, the Bureau of Mines, U.S. Department of the Interior, is conducting research on methods for beneficiating the oxidized taconite resources located on the western Mesabi range in Minnesota, thus expanding domestic iron ore reserves. The selective flocculation and cationic flotation process was investigated in a pilot plant using an ore feed rate of 410 kg/hr (900 1b/hr) and 88 percent recycled water. Lime and a cationic flocculant were used to clarify the waste slurries treated in the water reclamation circuit. An oxidized taconite assaying approximately 36 percent Fe yielded concentrates averaging 63.5 percent Fe and 4.3 percent SiO2 and having an average iron recovery of 84.4 percent. The estimated reagent cost per tonne of concentrate was approximately $1.10. In an attempt to recover more of the iron lost in the flotation tailing, wet high-intensity magnetic (WHIM) separation was incorporated in the pilot plant circuit. The flotation concentrate grades obtained from beneficiation circuits with and without WHIM scavenging were similar, but when WHIM separation was used the overall iron recovery was increased by 2 to 9.5 percent, depending on the iron assay of the flotation tailing.

Jan 1, 1978

By Achilles J. B. Dutra, Carlos M. Juarez

"The use of thiourea as a gold leaching reagent has been extensively studied by many researchers, and it has proved to be promising for some cases as refractory ores. Otherwise, the recovery of gold from these solutions did not receive so much attention. In this paper the electrowinning of gold in acidic thiourea solutions was studied by voltarnmetry and chronopotentiometry. An adsorption step was detected prior to Au(I) reduction and the diffusion coefficients at 25°C for Au-TU complex and FD were found to be 1.00 x 10.5 cm2 S-I and 1.98 x 10-5 cm2 S-I respectively. At -0.350 V (SCE) a passivation probably due to TU adsorption was observed. For higher overpotentials hydrogen evolution was the main reaction.IntroductionThe use of acidic thiourea solutions for the extraction of gold and silver has shown to be a promising alternative to the traditional process of cyanidation, specially for certain refractory ores (1-3) and electronic scrap (4). In some cases, the industrial scale was reached (1,5). The thiourea leaching of precious metals presents advantages over cyanidation, as faster kinetics, lower toxicity and lower sensibility to base metals; however the costs due to high thiourea consumption impairs its use.The majority of the publications on thiourea processing of gold is on leaching. Many are review papers (5-7). Recently, the adsorption and desorption of the gold-thiourea complex on activated carbon and ion exchange resins have been studied (8-11).Little research has been done on the electrowinning of gold from acidic thiourea solutions, most of it has been carried on the seventies and beginning of the eighties in the former USSR (12-17) and concerned the eletrolytic extraction of gold in tridimensional cathode cells.The present paper concerns the cathodic behavior of the gold-thiourea complex in the presence of formamidine disulfide in order to provide information on the electrowinning of gold from solutions obtained directly from leaching or from an elution process."

Jan 1, 1997

By E. Johansson, T. Siren, K. Kemppainen

"As part of the preparations for the design of an underground repository for radioactive waste at Posiva’s Olkiluoto site on the west coast of Finland, there has been considerable site investigation work. Except the extensive surface based investigations, Posiva started in 2004 the construction of an underground characterisation facility termed the ‘ONKALO’. The ONKALO has now been completely excavated to the anticipated repository depth i.e. -430–450 m. The research conducted in the ONKALO gives further information on the bedrock and groundwater conditions of the final disposal site, as well as on the impact of the construction. The ONKALO provides an excellent opportunity to investigate the rock at tunnel scale, to conduct in-situ testing in rock, to develop excavation and final disposal techniques in realistic conditions. The ONKALO has aided in collecting the data needed, supported by a Preliminary Safety Assessment, for the application of the construction license that was submitted in the end of 2012. The target is to begin disposal operations in 2022. According to current plans, the final disposal would end in 2112 and the repository would be sealed up by 2120. The testing in the ONKALO still continues several years. This paper presents the current characterisation and research activities in the ONKALO. INTRODUCTIONAfter the Finnish Government's favourable policy decision in 2001, Posiva Oy, which is an expert organisation responsible for the final disposal of spent nuclear fuel of the owners in Finland, has focused further investigations at the Olkiluoto site, western Finland (Figure 1) and has started in 2004 the construction of an underground facility termed the ‘ONKALO’. The ONKALO is not a nuclear waste repository, but more than just an underground research laboratory URL – it is an underground rock characterisation facility. The ONKALO has now been completely excavated to the anticipated repository depth i.e. -430–450 m. In addition to facilitating bedrock research, the ONKALO also provides an opportunity to develop excavation techniques and final disposal techniques in realistic conditions. Later, the ONKALO facilities can be put into use when building and using the repository. The construction methods and materials have been selected in order not to jeopardise the long-term safety of the repository site. The findings of the ONKALO and other investigations will provide the knowledge needed for an application, supported by a Preliminary Safety Assessment, to construct a final repository for spent nuclear fuel at the site. Posiva has submitted an application for the construction licence for a disposal facility in the end of 2012. The target is to begin disposal operations in 2022 and the repository would be sealed up by 2120."

Jan 1, 2015

By Zeynep Aktuna

In this study, the formation of zeolites around Kizkapan and Karlikoy villages (Sothwest Kesan) were investigated. In this region, stratigrafically, Upper Eocene Kesan Formation, i.e. sandstone and rarely shale are observed at the bottom. Early Middle-Oligocene Yenimuhacir Formation is composed of sandstone, marl and tuffs. The zeolitisation is determined in the dasitic tuffs of the Yenimuhacir Formation. In this tuffs' zone, alteration had primarily resulted in zeolites, mainly mordenite, heulandite-clinoptiIolite. Silicification and alteration to clay minerals are also common. The Miocene-Pliocene Ergene Formation and alluvium deposits are the top units in the area. In the studied area, zeolite occurences have economic importance. The results show that successively rapid and short term periods are responsible for the clinoptilolite-heuylandite formations. The homogene chemistry of the solutions may be evaluated for a possible successive zeolitisation period. Multi-periodic vocanic activity and also circulation of thermal water had resulted in a continous dissolution of volcanic glass; moreover, resulted in the formation of suitable conditions of zeolite formation. The mineral crystallization sequences and alteration products as zeolites within the wall-rock, circulated solution reaction depends on a serie of parameters such as chemical composition of both initial materials and volcanic solutions during rock¬solution interaction period. The previous researches and the chemical studies support our results and observations in the studied area. The aim of this study is to investigate the presence of zeolitisation and to explain the formation steps of zeolitisation in Kesan Area by considering the content and distribution of major and minor elements determined in zeolite bearing tuffs. The chemical structures of both zeolite bearing volcanics and zeolite minerals are compared to the results of previous studies. Two dimentional behaviours of major and minor elements were discussed in order to caracterize zeolitisation development and to postulate a probable formation type of zeolitic alteration.

Jan 1, 2005