Rare Earth Content of Manganese Nodules in the Lockheed Martin Clarion-Clipperton Zone Exploration Areas

Abstract

Abstract Lockheed Martin has conducted an analysis of the rare earth content ofClarion-Clipperton Zone (mid-Pacific) manganese nodules using samples from itsarchive from the 1970s/1980s. The rare earth content of these manganese nodulesis economically significant, and essentially uniform over large areas. Additionally, manganese nodules have low thorium and uranium content relativeto land based rare earth ores, and therefore may provide an inherentlyenvironmentally cleaner and economical source for rare earths. Introduction From 1978 to 1981, Lockheed Martin collected thousands of manganese nodulesamples from the seabed of the Clarion-Clipperton Zone of the Pacific Ocean. This was done as part of a $500M (in 2010 adjusted dollars) effort in manganesenodule mining. Due to the increasing technological importance and economicvalue of a wide range of rare earths, in early 2011 samples from 79 locationsacross Lockheed Martin's original US licensed claims were submitted to acommercial laboratory and assayed for rare earth content. The followingsections describe the results and economic implications of this study. Background In the 1970s/80s, Lockheed Martin led a consortium of companies in an effort todevelop a commercial mining operation for deep seabed manganese nodules. Manganese nodules form on the seafloor at water depths between 4 km to 5 km(USBoM, 1985). The most commercially attractive manganese nodules are those inthe Clarion-Clipperton Zone (CCZ) in the Pacific Ocean which lies betweenHawaii and Mexico (USBoM, 1985). In the 1970s/1980s, the interest in CCZnodules was due to their content in Ni (1.4%), Cu (1.3%) and Co (0.25%). Today, Mn (30%) and rare earth elements (0.08%) add to their potential commercialvalue. The Lockheed Martin consortium spent over $150M (approximately $500M in 2010dollars) to extensively survey its claims in the CCZ, and to develop manganesenodule mining and metallurgical processing technology. Under Lockheed Martin'sUS exploration licenses (Figure 1), a detailed survey of the claims wascompleted, with thousands of separate samples of nodules retrieved from theseabed. The nodule retrieval techniques included both free fall grab and boxcoring. In addition to these surveys, Lockheed Martin designed, developed andtested a pilot-scale seabed mining system in the CCZ (Figure 2). The systemincluded a seabed nodule collector and crusher system, a seabed-to-surfacenodule slurry riser system, a dynamically positioned surface ship, and ametallurgical processing plant specific to seabed nodules. Over eighty patentsrelated to this effort were generated, including many related to deep sea powerand remote control technologies and techniques. The Lockheed Martin consortiumemployed the M/V Glomar Explorer, which was the first vessel to employ dynamicpositioning and riser pipe heave compensation on an industrial scale. TheLockheed Martin mining effort was scaled back in the mid-1980s as a result ofuncertainty over international mining regulations and deflated commodityprices. Manganese Nodule Sample Collection and Analysis Figure 3 shows the 79 locations of the samples from the Lockheed Martin archiveused in this study. The samples were chosen due to the relatively high (>15 kg/m^2) estimated abundance of manganese nodules in their locality. Blindreplicates for six of the samples were included for a total of 85 analyzedsamples.