Microtopographic analysis of cobalt-rich manganese deposits on a mid-Pacific seamount

Abstract

Evaluation of stereo photographs and video data shows a variety of surface features associated with the crusts and nodules across a mid-pacific seamount. The differences in the coverage, distribution and relief are used to classify the surface features. The crust outcrops have large coverage (up to 100%), and their surface features vary from steplike to lineated and from cobble-type to nodular, giving rise to variable relief (from few centimenters to several meters). The relief is relatively low (10-20 centimeters) around the locations with crust outcrops along with nodules, and much less (~10 cm) in the areas of nodule fields. The microtopography (and relief) also varies between locations depending on the association of sediments with crusts and nodules, as well as their respective coverages. The occurrence of different types of surface features on the Co-rich manganese deposits and the resulting microtopography can have significant implications not only in the design of the mining system but also in planning the mining operation. The design of the miner head should be such that it can scrape the oxide layers along the microtopographic undulations on the crust surfaces as well as pick up the nodules in the viscinity. At the same time, it must also be designed to penetrate the sediment layer to collect shallow buried deposits and to separate the associated sediments befor lifting the deposits to the surface