Exploration Approach and Methods for Au-Ag-Cu Deposits 

Gold deposits spread at several spots around the world. The distribution can be known by its geographic coordinates. There are 764 of 855 spots of gold deposit with known geographic coordinates. One location of gold deposit can have different setting and type of deposit to other locations. Not only gold deposits who have different setting and type of deposit in different locations, but also copper deposit.

By doing holistic approaches, exploration are changing and developing day by days. Holistic approaches can be done by doing some exploration methods more scientific and through multi disciplinary. Holistic approach also looks exploration through multiple dimension and more contextual. Those approaches are considering multi scales and certain parameters. Exploration targets and key selection criteria can be looked by deposit age, types, or geology terrain. There are some vectors to lead us to ore :

  • Lithology (intrusion-centered)
  • Alteration types and pattern/zoning
  • Sulfide mineralogy
  • Ore metals and association
  • Gangue minerals
  • Textures of mineralization
  • Form of Mineralization

Geology is the key of exploration, by mapping we can observe, compile, and make analysis integration. There are number of methods and techniques which can be used in exploration:

  • Geochemical techniques: stream, gas water, soil, rock, fauna, flora, lithogeochemistry, sulphur isotope geochemistry
  • Geophysical techniques: seismic, gravity, magnetic, electromagnetic, IP, SP, Mise-a-la-masse
  • Remote sensing: air photos, satellite images, lidar, crosta analysis, clay index, structural geology, etc
  • Geological techniques: geological mapping, lithocaps, leached capping appraisal, porphyry mapping, mineral indicators, petrology/petrography
  • Other techniques and methods: ASD, XRF, XRD

The successful explorers will be those who strive to make the most effective use of a broad combination of the exploration methods available.

Indonesia itself has several challenges in exploration, they are :

  • Regulatory aspects: new model in the making, Law 4 year 2009 and Law 23 year 2014, certainty (royalty, tax)
  • Implementation aspects: ESDM and Forestry, Provincial and Kabupaten
  • Operational challenges: land access, overlapping lands, illegal mining, social expectations, “carrot vs stick” to be enforced
  • Perceptions challenges: mining and exploration, today and future
  • Technical challenges: discovery trends, deeper, more costly, lapse times
  • Declining gold and copper productions (2014 and 2005)