2. Offshore mining continues to provide a major
share of the world's limonite, retile, zircon, and tin
supplies.
A better understanding of shore processes, more
detailed offshore bathymetry, and more complete
information on pale geographic history are being
used to locate and evaluate marine placer
deposits.
3. MAJOR REGIONS OF OFF SHORE
MINING
• offshore mining in
Australia, Brazil, England, India, Japan, Malaysia, New
Zealand, South Africa, and the United States of America.
Prospecting activity has recently taken place on the Bering
Sea floor adjacent to the Seward peninsula, Alaska; the
Celtic Sea floor adjacent to the Cornwall peninsula; and the
Gulf of Carpentaria floor west of the Cape York
peninsula, Australia.
4. TYPES OF OFF SHORE
MINING
Seabed mining can be subdivided into two components:
shallow marine mining
deep sea mining
5. SHALLOW MARINE MINING
• Shallow marine mining largely refers to the
extraction of mud, sand and gravel for construction
purposes.
• Also refer to the mining of valuable minerals in the
nearshore shallow waters.
• Mining for construction sand and precious stones
(diamond and other gemstones) in shallow marine
areas has been ongoing in various parts .
• Such mining is common in the Pacific Islands
region and the coastal areas of southern Africa.
6. DEEP SEA MINING
• Deep sea mining is a relatively
new, extreme, and dangerous mineral retrieval
process that takes place on the ocean floor.
• Ocean mining sites are usually around large
areas of polymetallic nodules at about 1,400 -
3,700 m below the ocean’s surface.
• The vents create sulfide deposits, which contain
valuable metals such
as silver, gold,opper, manganese, cobalt, and zinc.
8. Mining Technology Development
• Since the early 1990s, a number of developed countries
including Germany, Japan, China, Korea, India and the
United States, were reported to have been working on
developing new offshore mining systems for collecting and
lifting nodules .
• Shallow offshore mining industry and gas and oil production
technologies are transferable to deep seabed mining.
9. The planned mining system has three major
components:
a) a Mining Support Vessel (MSV),
b) a Riser and Lifting System (RALS),
c)and a Seafloor Mining Tool (SMT) .
The system is designed to operate at a production rate of
6,000 tonnes of SMS ore a day at Nautilus Minerals’
10. EFFACTS OF OFF SHORE
MINING ON ENVIRONMENT
As off shore mining is a relatively new field, the complete
consequences of full scale mining operations are unknown.
But it is believed that
• removal of parts of the sea floor will result in disturbances
to the benthic layer,
• increased toxicity of the water column and sediment
plumes from tailings.]
• Removing parts of the sea floor could disturb the habitat
of benthic organisms, with unknown long-term effects.
