Academic
Publications
ORIGINS OF CLAY MINERALS IN THE MOLYCORP MINE GOATHILL NORTH ROCK PILE, QUESTA, NM

ORIGINS OF CLAY MINERALS IN THE MOLYCORP MINE GOATHILL NORTH ROCK PILE, QUESTA, NM,K. Donahue,N. Dunbar,V. McLemore

ORIGINS OF CLAY MINERALS IN THE MOLYCORP MINE GOATHILL NORTH ROCK PILE, QUESTA, NM   (Citations: 1)
BibTex | RIS | RefWorks Download
There are three principle lines of evidence that indicate the clay minerals found in the Goathill North (GHN) rock pile at the Molycorp mine are predominantly a product of hydrothermal alteration, not weathering. The unweathered drill core and samples from GHN have similar types and abundances of clay-mineral groups based on XRD analysis. Chemical analyses from the electron microprobe reveal similar chemical compositions for the hydrothermal alteration clays in drill-core samples and clays found in the rock pile. Textural evidence gathered from petrographic and microprobe examination also suggests a hydrothermal origin for clay minerals. Purpose Rock piles, the preferred term by many in the metal mining industry today, refer to the man-made structures consisting of piles of non-ore material that had to be removed in order to extract ore. This material, referred to in older literature as mine waste, mine soils, overburden, subore, or proto-ore, does not include the tailings material, which consists of non-ore material remaining after milling. Stability of rock piles has become a concern at many mines in North America, because mines are typically required to develop and implement a mine closure plan and before bonding is released, long-term stability of these and other structures must be assured. Understanding how clay minerals form and the rate of clay mineral formation in the rock pile is important in order to determine if clay minerals will form as a result of weathering in the near- or long-term future. A critical increase in the amount of clay minerals within the rock pile could decrease the slope stability due to the effect of clays on hydrologic characteristics of the rock pile. The purpose of the Molycorp weathering study is to assess conditions and processes occurring in the rock piles, especially related to the physical and chemical weathering of rock-pile materials at Molycorp's Questa mine in Toas County, NM (Fig. 1). Weathering is the disintegration of rock by physical, chemical, and/or biological processes, at or near the surface that results in reduction of grain size, change in cohesion or cementation, and change in mineralogical composition. For the purpose of this study, weathering refers to the changes in the rock-pile material after emplacement. A key component of this investigation is to estimate changes in these materials, if any, that have occurred since construction of the rock piles, and subsequently develop a model to extrapolate changes that could occur in the future. As a result, it could be possible to determine the effect of weathering on the geotechnical behavior of the rock piles as a function of time. The current approach is to test the geotechnical behavior of samples across a range of weathering intensities that are characterized by petrology, mineralogy, and chemistry for samples collected from the existing rock piles and elsewhere in the Questa-Red River area. As part of this study, type and composition of clay minerals were examined to determine the origin of the clay minerals. Description of site
Cumulative Annual
View Publication
The following links allow you to view full publications. These links are maintained by other sources not affiliated with Microsoft Academic Search.
Sort by: