STUDY OF ALTERATION AND MINERALIZATION IN THE BIG GOSSAN SKARN DEPOSIT, UNDERGROUND MINE SITE OF PT FREEPORT INDONESIA, TEMBAGAPURA DISTRICT, MIMIKA REGENCY, PAPUA PROVINCE
The Big Gossan Skarn deposit is an ore deposit classified as a high-grade deposit at the mine site of PT Freeport Indonesia. Therefore, research study is needed to find out the percentage of precious metals content found in this location by conducting an analysis of megascopic and microscopic obse...
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| Format: | Final Project |
| Language: | Indonesia |
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| Online Access: | https://digilib.itb.ac.id/gdl/view/37281 |
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| Institution: | Institut Teknologi Bandung |
| Language: | Indonesia |
| Summary: | The Big Gossan Skarn deposit is an ore deposit classified as a high-grade deposit at the mine site of PT
Freeport Indonesia. Therefore, research study is needed to find out the percentage of precious metals content
found in this location by conducting an analysis of megascopic and microscopic observations to determine
the alteration zone and the mineralization zone, as well as knowing the percentage of the ore such as pyrite
and chalcopyrite contained in the Big Gossan area, underground mine site of PT Freeport Indonesia at level
2600, Crosscut 43, 44, and 46.
The megascopic observation was carried out to see the alteration and mineralization contact in the body of
the host rock. Based on the observations results, rock formations in this area can be divided into three
formations: ekmai kembelangan limestone kuarter formation, hornfels kembelangan kuarter formation, and
waripi tertiary formation. Big Gossan area can be divided into ten mineralization zones based on the
percentage of the pyrite and chalcopyrite minerals presence. Transparent minerals found at the location
include garnet, diopside, calcite, quartz, actinolite, tremolite, and epidote. In addition, the presence of
opaque minerals such as pyrite, chalcopyrite, magnetite, and hematite also can be found. The appearance
of the minerals is obvious on each of the alteration contacts and has a percentage that varies from the
prograde to the retrograde phases. The characteristical minerals of the prograde phase include garnet,
calcite, quartz, and diopside, while the retrograde phase minerals are actinolite, tremolite, epidote, and
anhydrite.
As the result of the microscopic observations for the thin section and polished section samples, the presence
of transparent minerals such as garnet, diopside, epidote, quartz, and calcite can be confirmed, as well as
the presence of opaque / ore minerals such as pyrite, chalcopyrite, magnetite, and hematite. |
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