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The AAPG/Datapages Combined Publications Database

AAPG Bulletin

Abstract


Volume: 63 (1979)

Issue: 4. (April)

First Page: 691

Last Page: 692

Title: Magnitude and Variability of Disequilibrium in San Antonio Valley Uranium Deposit, Valencia County, New Mexico: ABSTRACT

Author(s): Stephen C. Moore, N. G. Lavery

Article Type: Meeting abstract

Abstract:

The San Antonio Valley deposit is a flat-lying tabular body of uranium mineralization in the Westwater Canyon Member of the Morrison Formation. The deposit is elongate northwest-southeast, is approximately 1.6 km long and 0.3 km wide, and averages from 2 to 4 m in thickness. The "trend-type" deposit has a chemically reduced mineralogy and occurs below the water table.

The average disequilibrium factor for the deposit shows a 4% enrichment in chemical uranium. Variations occur throughout the deposit, however, with the northeastern edge being chemically excessive by 11% and the southwestern edge being chemically deficient. Three

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ore-reserve correction factors have been assigned, one to each of three longitudinal zones. This use of multiple correction factors will optimize mine planning and uranium recovery.

Vertical profiles of radiometric and assay data through ore zones show dispersion of daughter isotopes away from uranium concentrations. Horizontal data plots show removal of daughter isotopes from the northeastern edge of the deposit and fixation of daughter isotopes in the central and southwestern parts of the deposit. Local loss of uranium is also suggested in the central and southwestern parts of the deposit. It is hypothesized that recent groundwater flow from east to west has redistributed the isotopic species. This flow system caused both the local vertical migration of daughter isotopes and also the transport of daughter isotopes and uranium in the direction of the hydrologic gradient. These conclusions are based wholly on chemical and gamma-equivalent uranium assays.

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