Salamanca State Reserves

Click to Enlarge Images
Figure 1 - Salamanca Uranium Project
Figure 1 - Salamanca Uranium Project 
Figure 2 - Águila Area
Figure 2 - Águila Area 
Figure 3 - Sageras Resource
Figure 3 - Sageras Resource 
Figure 4 - Sageras Cross Section
Figure 4 - Sageras Cross Section 
Figure 5 - Palacios North Resource
Figure 5 - Palacios North Resource 
Figure 6 - Palacios North Cross Section
Figure 6 - Palacios North Cross Section 
Figure 7 - Alameda Area
Figure 7 - Alameda Area 
Figure 8 - Alameda South Resource
Figure 8 - Alameda South Resource 
Figure 9 - Alameda South Cross Section
Figure 9 - Alameda South Cross Section 
Figure 10 - Villar Area Airborne Radiometrics
Figure 10 - Villar Area Airborne Radiometrics 
Figure 11 - Regional Airborne Radiometrics
Figure 11 - Regional 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 South deposit, 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. An initial Mineral Resource Estimates for the Águila Area was announced in February 2010 following completion of a confirmatory diamond drilling program at the Sageras and Palacios deposits. In June 2010, Berkeley commenced RC drilling at Sageras and Palacios to infill and upgrade the resources and test for lateral and depth extensions. 

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 11.2 Mt at 405 ppm for 10.0 Mlbs (4.5 Kt) U3O8 including 96% 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 completed a confirmatory diamond drilling program consisting of 21 holes in a series of traverses across the deposit in February 2010. All holes intersected strong mineralisation consistent with the historical data. The initial Mineral Rsource Estimate announced on the 26th February 2010, included 30% Inferred Resources based on a drilling density of 50m x 50m or greater, mainly in the Sageras West area and the southern part adjacent to the restored Mina Fe open pit.  RC drilling to infill these areas commenced in June and was completed in July 2010 with 71 holes drilled for 4,301 metres. Following receipt of the final chemical assays, AMC Consultants (UK) have re-estimated the Mineral Resource. 

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 (2.1 Kt)  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 drilled 15 diamond holes on a series of traverses designed to confirm the historical drilling data. All holes intersected strong mineralisation consistent with the historical data

Over 90% of the February 2010 Mineral Resource is already in the Measured and Indicated categories so the recent RC drilling program was aimed at exploring the previously untested area between the the two main mineralised domains.  A total of 10 RC holes (1,112m) were drilled in this corridor but the results were negative with only 2 holes intersecting mineralisation below the initial resource model.  

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 6.5 Mt at 411 ppm for 5.9 Mlbs (2.7 Kt) 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 24.3 Mt at 455 ppm for 24.4 Mlbs (11.0 Kt) 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  20.2 Mt at 445 ppm for 19.8 Mlbs (9.0 Kt) U3O8, including 92% 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 completed a confirmatory diamond drilling program consisting of 19 holes in a series of traverses across the deposit in March 2010.  The detailed results were  announced (18th Mar 2010 - Alameda Drilling Update) with all of the Berkeley holes intersecting mineralisation consistent with the historical data. An initial Mineral resource Estimate was announced on the 30th Marchm with approximately 50% classified as Inferred where the drilling density was 50m x 50m or greater. The recent RC drilling program, comprising 33 holes (3,554m), was aimed at infilling these areas and was completed in August 2010. All samples were sent to ALS Chemex in Vancouver for chemical analysis.  Assay results confirmed the initial resource and identified additional potential down dip.  

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.

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

The Alameda North deposit consists of 3 separate zones extending north from Alameda South over a distance of 3.5km along the granite margin.  An Inferred Mineral Resource of 4.1 Mt at 503 ppm for 4.5 Mlbs (2.1 Kt) U3O8 has been estimated for the Alameda North deposit.

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 (2.2 Kt) U3O8 has been estimated for the Villar deposit.

Exploration Potential

As well as the deposits described above, ENUSA identified 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.