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Tachie-Menson, Vanesssa Viterbo, Virgil W. Lueth, and Andrew R. Campbell Abstract. Rarely do rock pile characterization studies allow for petrographic, mineralogical, and geochemical characterization of the undisturbed interior of large rock piles in-situ. The regrading of the stable portion of Goathill North (GHN) rock pile at the Molycorp Questa molybdenum mine, New Mexico, provided an opportunity to examine and sample rock pile material in-situ through the construction of trenches cut into the rock pile as earth-moving progressed. Maps of each bench were created to describe the different stratigraphic units, including the thickness, dip, and extent of the units. Units were defined based on grain size, color, texture, stratigraphic position, and other physical properties that could be determined in the field. Units were correlated between benches and to both sides of each trench, and several units were correlated downward through the excavated trenches in the rock pile. Characterization of original rock pile material was accomplished by petrographic, mineralogic, and chemical analysis and includes descriptions of rock fragment lithology, mineralogy, texture, and alteration type and intensity. Rock fragment lithology is generally consistent within mapped units and correlates well with mineralogy and chemistry. Typically, paste pH and carbonate abundance increases with distance from the outer, oxidized zone (west) towards the interior, unoxidized zone (east) of the GHN rock pile. Conversely, authigenic gypsum, which is likely a product of in-situ weathering, usually exhibits a decrease in abundance from the outer to the inner portion of the rock pile. CaO and Sr also typically increase in concentration from the outer, oxidized zone (west) towards the interior, unoxidized zone (east) of the GHN rock pile, suggesting dissolution of feldspars and calcite to form gypsum in the outer, oxidized portions of the rock pile. Clay mineral and electron microprobe analyses of soil samples and unweathered drill core imply that the majority of clay minerals in the GHN samples are derived from the original pre- mining hydrothermal alteration and not by oxidation of minerals within the rock pile.

Uranium—Cradle to Grave. P.C. Burns and G.E. Sigmon 2013. Mineralogical Society of Canada, Short Course Series, v. 43. 437 Pp. ISBN 978-0-921294-53-5. Price $60 US. Uranium—Cradle to Grave is a much needed comprehensive volume written by internationally recognized experts on one of the more important and controversial elements in modern society: uranium. This volume examines topics including the origin and distribution of uranium ore deposits, mineralogy, chemistry, and nuclear waste disposal. The first chapter is short but well written, and presents an excellent introduction to the volume. The chapter summarizes the historical perspective on uranium, from the discovery in 1789 to the growing pains of the use of uranium, first in nuclear weapons (1945), then in nuclear reactors (1950), and the need to provide electricity for 30 countries. The author ends with a cautionary note that although there are 435 nuclear power plants in operation (at the end of 2011), worldwide demand for nuclear power will determine the role uranium will have in the world. The second chapter continues with the theme of the volume by describing some of the early uses of uranium as a coloring agent in …

A reconnaissance study of base metals and mercury in stream sediments from along the Pecos River from North-eastern to South-eastern New Mexico showed elevated levels of copper, lead and zinc at two areas: below an abandoned mine waste dump and below an inactive mill. Zinc was also present at elevated levels in the area of a fish hatchery. During subsequent sampling trips, stream-sediment samples were collected from tributaries as well as the main stem of the river from the Pecos Wilderness boundary south to Villanueva State Park, a distance of approximately 88 km. Sediments were sieved to obtain the 2 mm to 63 µm and

More than 100 carbonatite dikes and veins intrude a complex Precambrian terrain in the Lemitar Mountains, New Mexico. These Ordovician carbonatites are not associated with any alkalic rocks or kimberlites, but they exhibit textures, mineralogy, chemistry, and alteration characteristic of carbonatites. Despite variations in texture, the Lemitar carbonatites can be grouped on the basis of mineralogy, chemistry, and texture as primary-magmatic and replacement silicocarbonatites and rodbergs. The Lemitar silicocarbonatites consist of more than 50% carbonate minerals and varying amounts of accessory minerals, and they are enriched in LREE. The rodbergs consist of more than 50% carbonate minerals, are stained red by hematite, and exhibit flat REE patterns. Carbonate and barite-fluorite-galena veins of uncertain origin are found in the carbonatites and country rocks. Periodic episodes of alkalic magmatism occurred in New Mexico and southern Colorado during the Proterozoic, late Paleozoic, and Tertiary. The Lemit...