Stickney Rim Neodymium Field

The Stickney Rim field is a shallow, easily worked rare-earth deposit draped across the western rim of Phobos's largest crater. Ejecta from the impact concentrated phosphate grains rich in neodymium and praseodymium into a blanket between the surface and about 60 metres down.

The field was found the slow way: on foot and on wheels. Kofi Mensah-Hart's rover crews drove Lodeseeker Prospector Rovers along 340 kilometres of traverse, using ground-penetrating radar to map the blanket's thickness and stopping every 500 metres for Spectra Assay Lance readings. Of the 14,200 sample points later published in the Phobos LIBS Assay Atlas, more than 4,000 come from this rim.

Average grades are 1,850 g/t neodymium, 420 g/t praseodymium and a valuable 95 g/t dysprosium, over an indicated resource of 210 million tonnes. Because the material is loose and the gravity is almost nil, it can be scooped rather than blasted. The Guild registered claim FV-0577 in 2183 and leases it to the Phobos Regolith Syndicate, which runs the pit and ships concentrate to Mars aboard Wren Microlifters.