Mark J. Mihalasky

Spatiotemporal Analysis of Changes in Lode Mining Claims Around the McDermitt Caldera, Northern Nevada and Southern Oregon

Resource managers and agencies involved with planning for future federal land needs are required to complete an assessment of and forecast for future land use every ten years. Predicting mining activities on federal lands is difficult as current regulations do not require disclosure of exploration results. In these cases, historic mining claims may serve as a useful proxy for determining where mining-related activities may occur. We assess the utility of using a space–time cube (STC) and associated analyses to evaluate and characterize mining claim activities around the McDermitt Caldera in northern Nevada and southern Oregon. The most significant advantage of arranging the mining claim data into a STC is the ability to visualize and compare the data, which allows scientists to better understand patterns and results. Additional analyses of the STC (i.e., Trend, Emerging Hot Spot, Hot Spot, and Cluster and Outlier Analyses) provide extra insights into the data and may aid in predicting future mining claim activities.

Assessment of undiscovered resources in calcrete uranium deposits, Southern High Plains region of Texas, New Mexico, and Oklahoma, 2017

[Nknown, number of known deposits in the tract that have identified resources; Nund, number of undiscovered deposits calculated using a regression equation (Singer and Menzie, 2010); U3O8, uranium oxide; lbs, pounds. The permissive tract area in square kilometers (km 2) is inclusive of the favorable and prospective areas. Identified and undiscovered uranium resources are estimated as in-place. See Singer and Menzie (2010) for an explanation of quantitative mineral resource assessment methods]

Undiscovered Phanerozoic Porphyry Copper Deposits—A Global Assessment

Porphyry copper deposits represent the principal source of global copper supply. To address the questions of where future copper supplies are likely to come from and how much copper could exist within the upper kilometer of the earth’s crust, the USGS led a cooperative international effort to assess the world’s undiscovered Phanerozoic porphyry copper deposits using a geologybased, probabilistic form of mineral resource assessment (Singer and Menzie, 2010). Globally, 175 tracts permissive for porphyry copper deposits were defined to include volcanic and intrusive rocks of specified ranges of age and composition. The rocks represent: (1) magmatic arcs that developed on continental crust above subducting oceanic plates, (2) island arcs that formed on oceanic crust, and(or) (3) postconvergent magmatic belts within continents. Quantitative assessments of undiscovered resources were done for 155 of those permissive tracts.