Proven Deepwater Technology

Capitalizing on two decades of experience in offshore exploration in our partner SeaBird Exploration, enables Green Minerals to take a leading role in the development of the marine minerals industry from the outset

The technologies are largely known through a combination of established mining technologies and deepwater oil&gas. Green Minerals aims to modify these technologies to optimize flowrates and costs. We are working on several studies organized under two main areas within exploration and production systems. We cooperate with leading academic institutions in marine minerals as well as innovation programs in EU and Norway targeted at the green shift. We will announce key milestones as we progress towards the first licencing round.

The Norwegian government has opened more than 281,000 km2 for minerals activities. The vast and brutal area has steeply elevated subsea mountain ridges and seamounts in the deep abyss. Mountain sides with more than 1000 m of elevation difference, steep ridges, and deep trenches are the environment pioneers are moving into to secure minerals and metals for the green transition.  

The Seafloor Massive Sulfide deposits are located along the slow to ultra-slow spreading ridges of Mohn and Knipovich. Along the ridges, the University of Bergen and the Norwegian Offshore Directorate have acquired knowledge and valuable data for the last two decades. This has resulted in several discoveries of active, inactive, and extinct hydrothermal vent systems (figure 1). All the data and knowledge acquired by Norwegian authorities and academic institutions will help us identify prospective areas.  

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Figure 1. Discovered active, inactive and extinct hydrothermal vent systems along the Mohns and Knipovich Ridge.

A copper-rich sulfide deposit is expected to be the size of a football field. To be able to turn prospects into drillable candidates for mineralization testing a combination of data and techniques are required. High-resolution bathymetry together with synthetic aperture sonar is necessary to understand the surface expression of the deposit and potentially identify extinct vent structures. Electromagnetic data and Self Potential (figure 2) data will be among the used techniques to identify the prospect based on natural conductivity and electromagnetic properties of the sulfides as copper is a very good conductor of electricity. All these techniques and technologies and physical sampling will be a basis for drilling candidates.  

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Figure 2. High-resolution bathymetry with Self Potential anomaly over the Mohns Treasure deposit.

To be able to test the mineralization and understand the grade of the ore, drilling is needed. Several drill cores within the ore body are needed to get control of the grade, and distribution and to be able to model the orebody and its outline. Norwegian Offshore directorate tested coring with coil-tube technology in 2020 (figure 3) and was able to recover approximately 10 m of core.  

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Figure 3: Slabbed core from the Norwegian Offshore Directorate coring campaign 2020 (Sodir, 2020)

To understand the impact of a mining operation it is vital to understand the environment we are operating in. During exploration campaigns and drilling campaigns environmental monitoring and sampling will be of high priority to increase the understanding of the deep-sea environment. To be granted a production permit an environmental impact assessment must be conducted for the specific project area. In the Pacific Ocean in the Clarion Clipperton Zone (CCZ) environmental data acquisition and understanding has increased rapidly in the last decade. In Norwegian waters, we should acquire the environmental data at an earlier stage to increase our understanding based on the learning made from CCZ (figure 4).

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Figure 4. Environmental monitoring sensors (Halboom et al., 2022)

Green Minerals, in collaboration with OSI Minerals and Soil Machine Dynamics (SMD), is working on a production concept that builds on state-of-the-art technologies adapted to Norwegian conditions. Notably, Green Minerals introduces the use of a Disconnectable Turret (6) to alleviate the challenging Ship-To-Ship operations for ore-offloading and personnel transfer: 

 

  • The production cycle (figure 5): 
    1. The mined ore is mixed with seawater for transportation as a slurry by the Seafloor Mining Tools (1), 
    2. The slurry is lifted by the Pressure Exchange Chamber (PEC) (2)
    3. The slurry is vertically transported to the ore carrier via the riser system (3) and the flexible hoses connecting the Mining Platform (4) to the Ore Carrier via the Disconnectable Turret. (6,5) 
    4. The slurry is dewatered on the ore carrier: the dewatered ore is stored for transit to shore and the seawater is returned as hydraulic power to the PEC
    5. When the Ore Carrier reaches its ore capacity, the Turret is disconnected, lowered to a storage depth and ready to be recovered by the stand-by empty Ore Carrier 
  • The Seafloor Mining Tools, designed by SMD, result from previous designs and experience acquired on SMS projects and tests in wet conditions. 
  • The Vertical Transport: 
    1. is centralised on a riser solution that has been delivered and tested in Japan and the Area for marine minerals project, 
    2. achieves a semi-closed loop where deep seawater is returned to the seabed after dewatering 
  • The Ore-Carrier (5) is equipped with a helipad allowing for a short-distance helicopter transfer from/to the Mining Platform (4) 
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Figure 5. The production cycle.