Physical Properties and Mechanical Cutting Characteristics of Cobalt-Rich Manganese Crusts

摘要

Preliminary engineering data were developed for the mining of the cobalt-rich manganese crusts that occur in the Exclusive Economic Zone of the Hawaiian Archipelago. The research was divided into the following sections: (1) physical, mineralogical, and chemical descriptions; (2) mechanical property testing, such as compressive strength, tensile strength, and a rippability index; and (3) mechanical cutting characteristics, including average and peak cutter forces, the specific energy and cuttings size distribution. The manganese crust samples were mainly manganese and iron oxides and hydroxides with an average cobalt content of 1 pct and had a nucleus or substrate of rock or sediment. The significant results shown by the mechanical property and cutting tests are that the crust and all but two types of substrates (basalt and trachyte) are weak materials and easily cut with standard drag cutters. The crusts are generally comparable to medium-hard coal in strength and in their resistance to cutting.