exploiting inaccessible deposits

• polymetallic nodules are found at depths at 4000-5000m they contain around 30 percent manganese
• polymtallic nodules are metal rich nodules found on the seabed
• polymetallic nodules largescale exploitation will be difficult and expensive. additionally it will require international agreement on land onwenership
• largescale exploitation of polymetallic nodules has many environmental impacts:

  disturbance to seabed, killing benthic organisms, increase turbidity of water, redeposition of sediment can cover or kill organisms
• waste can come from either pre-consumer wastes or posts-consumer wastes
• seperating of materials when recycling is important, mixture of materials decreases quality
• ADV: recycled materials are lighter than raw materials
• ADV: transport instead of extraction is more cost-effective
• DISADV: smaller quantities being processed increases the labour cost
• ADV: recycling requires a lower skill level than extraction hence there are lower labour cost
• DISADV: alloys are very difficult to separate in recycling
• DISADV: identifying the composition of recycled materials in labour intensive
• ADV: recycling saves energy that would be used for exttraction
• DISADV: transport if in small quantities can be more energy intensive than extraction
• good post consumer schemes help with public cooperation to seperate materials when recycling
• not everything can be recycled this results in waste losses
• CRADLE TO CRADLE DESIGN: involves design of products that ultimately increase the lifetime of the minerals in use through recycling. This is because an increase in mineral lifetime means a reduction in the need to exploit new reserves