The occurrence of manganese nodule deposits is reviewed. The kind and extent of data collected on sampling expeditions launched by Kennecott Exploration, Inc., is described. Examples of variations found in the metal content of manganese nodules and in their abundance per unit area are presented. The effect of variations found on the estimated in situ value of manganese nodule deposits is discussed. Photographs of sampling tools used for reconnaissance are shown. Exploration techniques and work required to adequately survey a manganese nodule deposit are Examined. Mention is made of basic problem areas investigated by Kennecott personnel in evaluating the potential of nodule deposits as economic sources of metals. Concluding remarks emphasize the variable nature of nodules in respect to their abundance per unit of area and chemical composition.
My objectives today are to offer some observations concerning the occurrence of manganese nodules, and to describe some of the tools and techniques we have used to locate and sample this kind of deposit. These observations stem from Kennecott';s ocean exploration program, first launched in 1962. A significant portion of this program was devoted to testing the reports that vast tonnages of copper, nickel, and other usable metals were contained in these sea-floor nodules.
Our initial work appropriately involved the collection and study of all published information relating to the occurrence and characteristics of these metallic agglomerations. Samples were dredged for processing and other analysis. The results of these efforts established the need for extensive sampling in selected ocean areas. Following a field test of newly developed exploration tools, we embarked on our first nodule reconnaissance cruise in 1967. By the end of 1970, we had logged the recovery of over 3000 samples during the course of our cruises in the Pacific Ocean alone.
An early outline of basic problems to be solved, included such questions as "Does a large, continuous accumulation of metal-rich nodules, in fact, exist? If so, how can we find and outline the deposit cheaply?"
These two questions were considered especially pertinent since, as late as 1966, only 200-odd assays of nodules were available for study -- these being taken from widely scattered locations within the entire Pacific Ocean basin. Abundance estimates or continuity determinations, at the time, were based on meager information. And, of course, it was common knowledge that ship time was the major cost for, any operations at sea. Considering these facts, along with other information available to us initially, we came to several conclusions:
An important goal of our group should be to reduce the amount of ship time required for collecting the kind and amount of data needed.
prospecting for manganese nodules requires collecting samples in a manner which will permit a realistic appraisal of their continuity -- both in grade and abundance.
