An Economic Feasibility Analysis for Combined Mining of Cobalt-rich Crusts and Phosphorous Ores in North-west Pacific

The importance of cobalt-rich crusts on the Pacific seamounts for possible future rare metal sources has been recognized these 40 years. The thin layer-type coverage and the micro-topographic undulation of substrates affect not only the excavation efficiency but also the economy of mining venture. Because of these distribution characteristics, no economic feasibility has been recognized through the past economic analyses. On the basis of a recent geological study about the basement rocks, a possibility of byproduct substrate recovery for phosphorous supply with cobalt-rich crust mining has been highlighted. In the mining model, the substrates are utilized as phosphorus ores for agricultural and chemical usages. Under some preliminary technical and economic assumptions, the possibility of combined mining of cobalt-rich crusts and phosphorous ores is examined on the basis of the byproduct usage. The results show a better economy of the venture including the substrate usage for phosphorous supply.