I think the know alot before hand if you read about the samples and look at all the photos.... Cu, Au, U, Ag, Ce, La, Co, P, F, Ba, Sr and REE http://www.sidex.ca/Vpub/ArtLan/lanthanides-english.pdf REE deposits are either primary (carbonatite deposits, vein-type deposits, polymetallic iron oxide deposits http://www.sidex.ca/Vpub/ArtLan/lanthanides-english.pdf The largest deposits are accompanied by large hydrothermal systems characterized by magnetite, hematite, chlorite, epidote, carbonates and albite Anomalous concentrations of Cu, Au, U, Ag, Ce, La, Co, P, F, Ba, Sr and REE