Karl J Ellefsen
Science and Products
Distribution of Fibrous Erionite in the United States and Implications For Human Health
Fibrous erionite, a zeolite mineral, has been designated as a human carcinogen by the World Health Organization and is believed to be the cause of extraordinarily high rates of malignant mesothelioma and other asbestos - related diseases in several villages in Central Turkey. A recent study by the University of Hawaii in collaboration with the U. S. Environmental Protection Agency in Dunn...
Effect of size-biased sampling on resource predictions from the three-part method for quantitative mineral resource assessment—A case study of the gold mines in the Timmins-Kirkland Lake area of the Abitibi greenstone belt, Canada:
The three-part method for quantitative mineral resource assessment is used by the U.S. Geological Survey to predict, within a specified assessment area, the number of undiscovered mineral deposits and the quantity of mineral resources in those undiscovered deposits. The effects of size-biased sampling on such predictions are evaluated in a case...
Ellefsen, Karl J.
Titanium mineral resources in heavy-mineral sands in the Atlantic coastal plain of the southeastern United States
This study examined titanium distribution in the Atlantic Coastal Plain of the southeastern United States; the titanium is found in heavy-mineral sands that include the minerals ilmenite (Fe2+TiO3), rutile (TiO2), or leucoxene (an alteration product of ilmenite). Deposits of heavy-mineral sands in ancient and modern coastal plains are a...
Van Gosen, Bradley S.; Ellefsen, Karl J.
Rare earth mineral potential in the southeastern U.S. Coastal Plain from integrated geophysical, geochemical, and geological approaches
We combined geophysical, geochemical, mineralogical, and geological data to evaluate the regional presence of rare earth element (REE)−bearing minerals in heavy mineral sand deposits of the southeastern U.S. Coastal Plain. We also analyzed regional differences in these data to determine probable sedimentary provenance. Analyses of heavy mineral...
Shah, Anjana K.; Bern, Carleton R.; Van Gosen, Bradley S.; Daniels, David L.; Benzel, William M.; Budahn, James R.; Ellefsen, Karl J.; Karst, Adam; Davis, Richard
Probability calculations for three-part mineral resource assessments
Three-part mineral resource assessment is a methodology for predicting, in a specified geographic region, both the number of undiscovered mineral deposits and the amount of mineral resources in those deposits. These predictions are based on probability calculations that are performed with computer software that is newly implemented. Compared to...
Ellefsen, Karl J.
User’s guide for MapMark4—An R package for the probability calculations in three-part mineral resource assessments
MapMark4 is a software package that implements the probability calculations in three-part mineral resource assessments. Functions within the software package are written in the R statistical programming language. These functions, their documentation, and a copy of this user’s guide are bundled together in R’s unit of shareable code, which is...
Ellefsen, Karl J. Titanium concentrations in stream sediments from the Atlantic Coastal Plain of the southeastern U.S. (1975-1999)
The titanium concentrations were obtained from a data set that is called the "National Geochemical Survey." This data set, as well as its documentation, are available in U.S. Geological Survey Open-File Report 2004-1001 (https://mrdata.usgs.gov/geochem/doc/home.htm). The titanium concentrations were measured in 3,457 samples of stream sediments...
Ellefsen, Karl J. Undiscovered porphyry copper resources in the Urals—A probabilistic mineral resource assessment
A probabilistic mineral resource assessment of metal resources in undiscovered porphyry copper deposits of the Ural Mountains in Russia and Kazakhstan was done using a quantitative form of mineral resource assessment. Permissive tracts were delineated on the basis of mapped and inferred subsurface distributions of igneous rocks assigned to...
Hammarstrom, Jane M.; Mihalasky, Mark J.; Ludington, Stephen; Phillips, Jeffrey; Berger, Byron R.; Denning, Paul; Dicken, Connie; Mars, John C.; Zientek, Michael L.; Herrington, Richard J.; Seltmann, Reimar
Feasibility study for the quantitative assessment of mineral resources in asteroids
This study was undertaken to determine if the U.S. Geological Survey’s process for conducting mineral resource assessments on Earth can be applied to asteroids. Successful completion of the assessment, using water and iron resources to test the workflow, has resulted in identification of the minimal adjustments required to conduct full resource...
Keszthelyi, Laszlo P.; Hagerty, Justin J.; Bowers, Amanda; Ellefsen, Karl J.; Ridley, Ian; King, Trude; Trilling, David; Moskovitz, Nicholas; Grundy, Will Magnetic and gravity gradiometry framework for Mesoproterozoic iron oxide-apatite and iron oxide-copper-gold deposits, southeast Missouri, USA
High-resolution airborne magnetic and gravity gradiometry data provide the geophysical framework for evaluating the exploration potential of hidden iron oxide deposits in Mesoproterozoic basement rocks of southeast Missouri. The data are used to calculate mineral prospectivity for iron oxide-apatite (IOA) ± rare earth element (REE) and iron oxide-...
McCafferty, Anne E.; Phillips, Jeffrey; Driscoll, Rhonda L. Coastal deposits of heavy mineral sands; Global significance and US resources
Ancient and modern coastal deposits of heavy mineral sands (HMS) are the principal source of several heavy industrial minerals, with mining and processing operations on every continent except Antarctica. For example, HMS deposits are the main source of titanium feedstock for the titanium dioxide (TiO2) pigments industry, obtained from the minerals...
Van Gosen, Bradley S.; Bleiwas, Donald I.; Bedinger, George M.; Ellefsen, Karl J.; Shah, Anjana K. Manual hierarchical clustering of regional geochemical data using a Bayesian finite mixture model
Interpretation of regional scale, multivariate geochemical data is aided by a statistical technique called “clustering.” We investigate a particular clustering procedure by applying it to geochemical data collected in the State of Colorado, United States of America. The clustering procedure partitions the field samples for the entire...
Ellefsen, Karl J.; Smith, David
User’s guide for GcClust—An R package for clustering of regional geochemical data
GcClust is a software package developed by the U.S. Geological Survey for statistical clustering of regional geochemical data, and similar data such as regional mineralogical data. Functions within the software package are written in the R statistical programming language. These functions, their documentation, and a copy of the user’s guide are...
Ellefsen, Karl J.; Smith, David B.