Cáceres III Uranium Project
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- Figure 1 – Cáceres III Regional Geology
- Figure 2 – Cáceres III Saguazal Drilling Area
The Cáceres III Uranium Project is situated in the west-central part of Cáceres Province, some 25 km northwest of the provincial capital (see Figure 1). It corresponds to the central part of the Cabeza de Araya Hercynian granitic intrusion in the late Precambrian formations of the Schist-Greywacke Complex. Berkeley's permits in the Cáceres III area cover 17,165 ha.
Uranium exploration in and around the Cabeza de Araya batholith commenced in the mid-1950s with the Junta de Energia Nuclear ("JEN") continuing activities until the late 1960s. In this period, the La Zafrilla deposit was located and put into exploitation for a short period during the 1960s.
The JEN recommenced exploration, but ceded these activities to ENUSA in 1974. ENUSA was active until the mid-1980's, when they also ceased exploration in this area. Subsequently CISA (a joint venture between COGEMA (now AREVA) and ENUSA) was active between 1989 and 1994.
Numerous uranium occurrences associated with this granitic intrusive have been located. The most interesting area appears to be the central part of the batholith which includes the Saguazal deposit. An application for an exploration permit to cover this area was made.
The Saguazal Deposit
Within the Cáceres III Uranium Project the main focus is the Saguazal deposit and its potential extensions. Saguazal was drilled by CISA in the early 1990's, with a number of significant high grade intersections close to surface. Ground radiometric surveys showed the main Saguazal mineralized zone has the potential to extend up to 4km westwards to and beyond the regional Plasencia Fault.
A program of 9 Diamond drill holes (SAG-001 to SAG-009) tested the CISA drilling area and produced a number of similar high grade results, including (at a 200 ppm cut-off):
| Drill Holes | Results |
|---|---|
| SAG-002 | 3.5 metres @ 506 ppm U3O8 from 15.0m |
| SAG-003 | 0.5 metres @ 590 ppm U3O8 from 5.3m |
| SAG-004 | 8.4 metres @ 372 ppm U3O8 from 12.3m |
| SAG-005 | 10.0 metres @ 362 ppm U3O8 from 13.0m |
High grade mineralization appears to be associated with explosive breccias zones containing fine sulphides (pyrite/marcasite) with little wall rock alteration. Zones of Kfeldspar alteration, although radiometrically anomalous, contain little uranium. Mineralised breccias maybe controlled by shallow, north-dipping structures the base of which is marked by a clay pug zone, below this zone the granite is fresh and mostly unaltered (except for minor areas of K-fledspar alteration on micro-fractures). The mineralization appears to occur in a sub-horizontal zone.