Scenarios for the Marine Mining of Heavy Minerals
Bart HogewegAndrina DrostRogier Kalis
Heavy Mineral Conference 2013Visakhapatnam, India27-29 November 2013
IHC Mining B.V.The Netherlands
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IHC Merwede Overview
IHC Merwede facts & figures:• Financial turnover in 2012: EUR 0.9 billion
• Staff in 2012: 3,200
• 5 Shipyards in The Netherlands, 1 in China; Singapore & Batam with Jaya Shipbuilding & Engineering
• World wide services and manufacturing locations
Outline
• Introduction• Marine mining technology• Mineral processing in marine environments• Marine mining scenarios• Conclusions
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Mining of the seafloor has been ongoing for a long time
• Offshore gold and tin mining started in early 1900s
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Introduction / Mining / Processing / Scenarios
Current marine mining activities are still based around historic areas…
• PT Timah operates offshore Indonesia with large integrated bucket ladder dredgers• In water depths to 50 m• Recently, IHC and PT Timah converted one of the dredgers to a hydraulic wheel
dredger, extending water depth to 70 m
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Source: PT Timah
Introduction / Mining / Processing / Scenarios
…but also moved into new areas
• De Beers Marine operates a mining vessel with a crawler offshore Namibia• Diamonds are mined from water depths to 150 m
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Source: De Beers Marine
Introduction / Mining / Processing / Scenarios
Heavy minerals are found offshore in relatively shallow water depths
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Offshore placers: Diamonds, gold, tin, heavy minerals (Ti-Zr)
PhosphatesCrust (Mn, Co)
Seafloor Massive Sulphides (Cu, Au, Zn)Nodules (Mn, Ni, Cu)
Source: GRID-UNEP
Introduction / Mining / Processing / Scenarios
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Heavy minerals are very suitable for dredge mining
• Richards Bay Minerals is world largest heavy minerals mining operation, using mining dredgers in multiple ponds
Introduction / Mining / Processing / Scenarios
How can we build a pond on the other side of the shore line?10
Introduction / Mining / Processing / Scenarios
Different concepts can be used for marine mining
• Stationary• Cutter/wheel suction dredger• Bucket ladder dredger
• Trailing• Trailing suction hopper dredger
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Introduction / Mining / Processing / Scenarios
Moving offshore brings in factors like wind, waves, currents etc.
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• Cutter suction dredgers are fixed to ground by spud wave action limits operation• Trailing suction hopper dredgers don’t have this limitation
Introduction / Mining / Processing / Scenarios
Wind and waves also have a large impact on the separation of heavy minerals
• Sea state and resulting vessel motions have impact on performance of separation equipment
• Vessel movements inhibit proper operation of spiral concentrators
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Introduction / Mining / Processing / Scenarios
Technology can provide solutions, but they come at a price
• Increase size of the platform to create more stability
• Motion compensation
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Source: Husky Energy
Source: Barge Master
Introduction / Mining / Processing / Scenarios
Combining mining and mineral processing results in different mining scenarios
• Integrated platform combining mining and mineral processing functions
• De-coupled functions
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Introduction / Mining / Processing / Scenarios
An integrated solution provides distinct benefits, but has limited application in sea state
• Single unit• Direct tailing repositioning, no tailing transportation required• Well suited for mining of thicker layers of material
• Limited sea state, as processing is integrated onboard the dredge
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Introduction / Mining / Processing / Scenarios
Separated functions provide more flexibility
• Opportunity to use trailing suction hopper dredgers
• Operating cycle: process is discontinuous
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Dredging
Transport
Transport
DumpingPumping ashore Rain-bowing
Introduction / Mining / Processing / Scenarios
Choices in mining cycle can create a variation of scenarios
• Similar to the operating cycle of the TSHD, a mining cycle can be setup• For each step in cycle, different options exist
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Mining
Transporttailings
Transport ore
Process plant Concentrate
Source: Van Oord
• TSHD• CSD• WSD
• Floating• Onshore
• TSHD• Barge
Introduction / Mining / Processing / Scenarios
Various scenarios are usually possible. Logistics determine the optimal scenario
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Example 1
Example 2
Example 3
Introduction / Mining / Processing / Scenarios
Finding the optimal requires thorough analysis
• Multiple technology solutions for marine mining are available
• Factors as proximity to shore, wind and wave conditions have a large impact on both the mining and mineral processing options for a mining scenario
• Mining scenarios are a combination of mining, processing and transportation methods selected on a project-to-project basis
• The optimal mining scenario is driven by logistics
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Introduction / Mining / Processing / Scenarios
