Salamanca State Reserves

Click to Enlarge Images
Figure 1 - Salamanca Uranium Project JORC Resources
Figure 1 - Salamanca Uranium Project JORC Resources 
Figure 2 - Águila Area Deposits
Figure 2 - Águila Area Deposits 
Figure 3 - Sageras Resource Model Grade Thickness Plot
Figure 3 - Sageras Resource Model Grade Thickness Plot 
Figure 4 - Sageras Resource Model Cross Section 700020E
Figure 4 - Sageras Resource Model Cross Section 700020E 
Figure 5 - Palacios North Resource Model Grade Thickness Plot
Figure 5 - Palacios North Resource Model Grade Thickness Plot 
Figure 6 - Palacios North Resource Model Cross Section 1600N
Figure 6 - Palacios North Resource Model Cross Section 1600N 
Figure 7 - Alameda Area Deposits
Figure 7 - Alameda Area Deposits 
Figure 8 - Alameda South Resource Model Grade Thickness Plot
Figure 8 - Alameda South Resource Model Grade Thickness Plot 
Figure 9 - Alameda South Cross Section 775N
Figure 9 - Alameda South Cross Section 775N 
Figure 10 - Villar Area
Figure 10 - Villar Area 
Figure 11 - Geology and Airborne Radiometrics
Figure 11 - Geology and Airborne Radiometrics 

The State Reserves include a number of mining permits in favour of ENUSA and were established by Act of Parliament entitling ENUSA to both explore and exploit the uranium deposits within the permits.

ENUSA, the Spanish State uranium company, operated uranium mines in Salamanca Province between 1972 and 2000, and these operations were centred on the Mina Fe mine. Prior to 1993 ore was processed through the Elefante plant (static leach) and from 1993 until cessation of mining activity through the Quercus plant (combined static and dynamic leach). Most of the mining pits, waste dumps and heaps at Mina Fe have been rehabilitated, however, the balance of plant, tailings dam and other infrastructure are intact.

The State Reserves have been extensively explored by ENUSA with a number of deposits delineated and drilled out to varying degrees.

ENUSA discovered six uranium deposits within its State Reserves, but mining was limited to the Mina Fe (Majuelos) deposit and to shallow mineralisation in the Mina D (Palacios North) deposit. Berkeley's feasibility study process will be focussed initially on the Águila area deposits (including Sageras and Palacios North) and the Alameda deposits, and will also investigate opportunities to incorporate Berkeley's existing resources in the Retortillo area.

The Águila area deposits are located within close proximity to the Quercus plant and are essentially part of the same mineralised system. The Alameda deposits are located 12km to the west of the Quercus plant and have not been explored as extensively as those at Águila.

The Águila Deposits

There are a number of deposits within the domain of ENUSA's former Mina Fe operation, largely located on ENUSA's owned property. These deposits, known as Sageras, Palacios and Majuelos are set out in Figure 2.

A residual resource still exists in the Palacios North deposit having been partially mined by ENUSA in three small pits. The Sageras deposit has not been developed.

These deposits can be considered as geological extensions of the previously mined Mina Fe (Majuelos) deposit and are located within 3 km of the Quercus processing plant. They are all hosted in typical Iberian lower Palaeozoic shales and are mineable by open pit methods. ENUSA reports that the metallurgy of the deposits should be very similar to the previously mined mineralisation at Mina Fe and Mina D.

Berkeley gained access to ENUSA's data in early June 2009 and considerable effort has been devoted to investigating this data including the resource models provided by ENUSA for the main deposits. Following the recent completion of a confirmatory diamond drilling program, Berkeley announced initial Mineral Resource estimates totalling 22.7mt at 417ppm for 20.7Mlbs U3O8 (200ppm cut-off) for the Águila Area deposits (26th Feb 2010 - Berkeley Doubles Resources).

Sageras

The Sageras deposit is interpreted as the North West extension of Majuelos and is located within 3 km of the Quercus processing plant (see Figure 2).  Total Mineral Resources have been estimated at 9.7 Mt at 400 ppm for 8.6 Mlbs U3O8 including 71% in the Measured and Indicated categories (200 ppm cut-off).    

The mineralisation is hosted in Palaeozoic metasediments and occurs at or close to the surface with widths varying from about 150m in the south-east up to 300m in the north-west. Close spaced drilling indicates a number of shoots with strong continuity in a north-westerly direction, parallel to a major geological trend extending from the restored Mina Fe open pit for a distance of approximately 1.5 km.  In cross section, the mineralisation is gently east dipping to sub-horizontal ranging from 10m to 50m in thickness and extends from surface to 100m deep (see Figures 3 & 4 - grade thickness plot and cross section).

The historical drill hole database for the Sageras and the Mahuelos deposits contains 12,900 drill holes consisting of a combination of 50m x 50m spaced diamond drill holes with chemical assays and 10m x 10m roto-percussion drill holes with e-grades generated from down hole radiometric measurements.  The western quarter (formerly Zona M) lies outside the ENUSA wholly owned land (Figure 2) and has been drilled on a 50m x 50m spacing.  Berkeley recently completed a confirmatory diamond drilling program consisting of 21 holes in a series of traverses across the deposit.  The detailed results were announced in January (22nd Jan 2010 - SUP Drilling Results) and all of the Berkeley holes intersected strong mineralisation consistent with the historical data.

Palacios

The Palacios Deposit (previously known as Mina D) is located within 1 km of the Quercus processing plant and is separated from the Sageras and Majuelos deposits by the Agueda River (see Figure 2).  The northern area (Palacios North) has been drilled out on a 10m x 10m spacing and Palacios South has been drilled out on a 50m x 50m spacing (Figure 2), therefore the two areas have been estimated separately.

The upper portions of the Palacios North deposit were mined by ENUSA in 3 small open pits during the 1990's (Figure 2).  Significant resources remain below the restored open pits and recent drilling by Berkeley has confirmed the thickness and grade of the historical drilling and provided a better understanding of the geology. Current estimates indicate total Mineral Resources of 4.2 Mt at 508 ppm for a total of 4.7 Mlbs U3O8, with about 90% in the Measured and Indicated categories.

In plan view, the Palacios North uranium mineralisation occurs as two broad north trending lobes, 600m - 750m in length, separated by a sparsely drilled central corridor up to a few hundred metres in width. The two lobes have mostly been drilled on a 10m x 10m pattern, except for the southern portion of the western zone where the spacing opens up to 20m x 20m and finally to 50m x 50m. A grade thickness plot of the resource is shown in Figure 5 and a section through the deposit in Figure 6.

The Palacios North deposit has been modeled using a drill hole data set of 2,668 drill holes.  Most holes are roto-percussion with down hole e-grades.  Berkeley's recent 15 hole diamond drilling program covered a series of traverses designed to confirm the historical drilling data. All holes intersected strong mineralisation consistent with the historical data.

Majuelos

The Majuelos deposit encompasses two areas:  remnant resources lying below the restored Mina Fe open pit and drilled on a 10m x 10m grid; and a separate zone to the east of the restored pit drilled on a 50m x 50m spacing (Figure 2). Total Mineral Resources have been estimated at 6.4 Mt at 411 ppm for 5.8 Mlbs U3O8, all in the Inferred category.

Most of the remnant resources occur at the margins of the pit, particularly in the south-east where a strongly mineralised zone, dipping at 30 degrees to the north-east, has been drilled to over 180 metres below the surface (historical drill intersection of 10m @ 428 ppm U3O8).  There is also a significant amount of unmined material around the north-west margin of the restored open pit and along the western boundary where mineralisation connects to the Sageras deposit. 

The Alameda Deposits

The Alameda South and North deposits are located approximately 14km to the west of the Quercus Plant (Figure 2) and have a combined total Mineral Resource Estimate of 22.5 Mt at 466 ppm for 23.1 Mlbs U3O8.  A breakdown of the individual deposit totals is shown in Figure 7.  Only the southern deposit is being considered in the Feasibility Study.

The Alameda South deposit was discovered in the 1960's and subsequently drilled out on a 50m x 50m pattern using diamond drilling with chemical assays. The deposit extends from the surface down to 120m and covers and an area of 2km by 1.2km with relatively flat surface topography. Total Mineral Resources have been estimated at 18.4 Mt at 458 ppm for 18.5 Mlbs U3O8, including 49% in the Indicated category.

The historical drill hole database for the Alameda South deposit contains 400 diamond drill holes for a total of 40,000m.  The drill spacing is 50m x 50m over the majority of the deposit although this has been reduced to 35m x 35m over the main central zone of mineralisation.  All of the historical assay data consists of chemical assays which have been checked against the historical drill logs. Berkeley has completed a confirmatory diamond drilling program consisting of 19 holes in a series of traverses across the deposit.  The detailed results were recently announced (18th Mar 2010 - Alameda Drilling Update) with all of the Berkeley holes intersecting mineralisation consistent with the historical data.  The e-grades from the Berkeley drill holes were combined with the historical chemical assay data for use in the estimate.

Uranium mineralisation at Alameda South is hosted by a deformed sequence of regionally and thermally metamorphosed quartz sericite pelites. In addition, granitic sills and shallow dipping dykes were intruded after the main folding and metamorphism events followed by the uranium mineralisation.  The mineralisation occurs in a complex network of moderately to steeply dipping brittle structures (veins, faults, fractures and along bedding contacts) as a result of a low temperature hydrothermal event.  The mineralised zones commonly have sharp boundaries, separating mineralised structures from poorly mineralised host rock, recent fracturing is partly responsible for this.

A grade thickness plot of the resource is shown in Figure 8 and a section through the deposit in Figure 9.

Villar Deposit

The Villar Area is located 10km north of Alameda and 14km north-west of the Quercus Plant (Figure 1).  The Area has been extensively explored since the 1960's but still contains a number of untested radiometric anomalies (Figure 10).  A small historical underground mine was developed at the Villar Deposit but only limited mining activity was undertaken.  

 Berkeley airborne radiometrics have highlighted the potential of the area and show that the Villar Deposit is located on a strong radiometric anomaly that extends to the south-west and links up with the Barquilla prospect where Berkeley drilled 7 diamond holes in 2008 (Figure 10).   An Inferred Mineral Resource of 5.0 Mt at 446 ppm for 4.9 Mlbs U3O8 has been estimated for the Villar deposit.

Exploration Potential

As well as the deposits described above, ENUSA identified the Esperanza deposit and six other prospective areas through a combination of radiometrics and drilling: Marialba, Cuellar, Carpio, Gallegos, Barquilla and north of Sageras (see Figure 11). In addition, Berkeley's experience indicates the high prospectivity of extensive areas of favorable stratigraphy below Tertiary and recent cover, where radiometrics are ineffective.

Figure 11 shows the uranium channel from helicopter-borne radiometric data with the northern block flown by Berkeley in 2007 and the southern block by ENUSA in the late 1980's. The radiometric anomalies are underlain by fertile basement metasediments and coincide with the prospects.