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kolar gold mines (1).pptx

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kolar gold mines (1).pptx

  1. 1. 1. INTRODUCTION 2. ORIGIN 3. FORMATION OF KOLAR GOLD 4. GOLD DEPOSITES SITUATED 5. KOLAR GOLD DEPOSITS 6. MODE OF OCCURANCE OF GOLD 7. CONCLUSTION
  2. 2. • All primary Gold deposits are formed usually during the late stages of the chilling of the magma ,which along fissures to the upper layers of the earth`s crust from great depths. The Gold is transported together with the magma from the depths of the earth in hot aqueous solution and vapors. These solutions get solidified with the falling of temperature, giving rise to ore bodies mostly in the form of veins in rocks. • These veins generally consist of Quartz with a small admixture of other minerals. The particles of gold in the form of fine grains, platelets and flaks and some times crystals wires, filaments etc. • In the course of time these rocks and veins under the action of geological agents, undergo mechanical disintegration and chemical decomposition. The weathered products while being carried down to the depositional site undergo the process give rise to placer Gold deposits
  3. 3. ECONOMICS GOLD MINERALS NATIVE GOLD GOLD AMALGUM TELLURIDE
  4. 4. Gold occurs many geological settings. The following are the important principal modes of occurrences observed in India.  LODE GOLD  GOLD IN CONGLOMERATE  STRATIFORM  PLACER AND ALLUVIAL GOLD  GOLD IN GRANULITE  GOLD IN LATHERITE SOILS  DISSIMINATED
  5. 5.  In Kolar Gold field the Gold deposits are associated with schistose rocks where aluminiumferous quartzite lodes occur along closely placed mineralized zones.  KGF is about 30 kilometers from Kolar and 100 kilometers from Bangalore.
  6. 6.  The Kolar Greenstone or Schist Belt covers a 3 - 6km wide area extending up to 80km in length. The rocks within the belt are comprised of complexly folded and faulted mafic and felsic volcanic sequence generally of low metamorphic grade.  The northern 40 km long portion of the belt has laterite cover restricts exploration work.  Gold is preferentially concentrated in vein quartz, often associated with sulphides. Most of these gold prospects represent typical Archean hydrothermal lode gold mineralization.  The three groups of the Kolar Gold Fields. 1. South Kolar 2. East Kolar 3. North Kolar
  7. 7.  North Kolar covers the northerly extension of the Kolar Greenstone Belt and includes major synformal fold.  Lode gold mineralisation is hosted by shear zones, sheared granite and quartz viens.  Quartz bodies of different types, both barren and mineralised and several generations occur in the ferruginous and carbonaceous Phyllites and within linear bodies of metagabbro.
  8. 8.  mineralisation occurs near to the contact of the mafic amphibolitic metabasalt with felsic volcanic and metasediments of the Champion Gneiss.  Gold is concentrated in vein quartz and also associated with sulphides.  The zone having highly sulphidic rocks and at one of the prospects and quartz viens on the other end.
  9. 9.  This horizon is a heterogeneous assemblage of volcano- sedimentary rocks.  The volcanics are represented by rhyolite and acidic tuffs of dacitic composition. All these are deformed and metamorphosed to lower amphibolite facies.  Gold mineralisation in the Surapalle area occurs in highly tectonised shear zones which transect the foliation at a very low angle.
  10. 10.  The Oriental lode of KFG is a stratiform sulphide type lode lying about 400 to 500 mts to the west of champion reef lode in north Kolar.  It is strongly a pyritic lode. Width of this lode is ranges from 1.5mts-4.5mts  This lode is localized between volcanic flows and it is made up of alternating bands of sulphide and amphibole- quartzite encountered in archian schist belts.  Dominating sulphide minerals are pyrhotite with arsenopyrite and minor pyrite chalcopyrite and sphalerite.
  11. 11. Kolar gold field have four productive mines 1. Nandydurg mine 2. Champian reef 3. Mysore mine 4. Ooregum  The champian reef mine is one of the deepest mine in the word.  The average content of champian reef was 15e grams/tonn  There were about 15 parallel lodes in thkolar gold field, in them 6 were gold-quartz lodes,9 were gold-quartz-sulphide lodes About 84 tones of gold have been produced since the mines were nationalized
  12. 12.  The gold -quartz lode is localized along a shear zone traversing the mafic rocks of komatitic and tholeitic character.  This lode have been mined over a strike lenth of more than 8 km and to depth of 3400 mts.  Lode are mainly made up of quartz and calcite .Other minerals include sheelite, biotite, muscovite, and tourmaline. Sulphides are pyrite, arsenopyrite, pyrhotite, chalcopyrite and galena. High values of Cr and Ni are also noticed
  13. 13.  Gold has been prised high and considered as king of the metals.  Kolar gold fields are important gold producing centers in karnataka  Champion reef is the richest gold bearing quartz-lode in so far encountered in india.  The champian reef mine is one of the deepest mine in the word.  Gold deposits generally occurs with quartzite and sulphide lodes within these two gold fields Main reef is the important gold producing reef among the Hutti gold field

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