Retortillo

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1. Retortillo Resources
1. Retortillo Resources 
2. Retortillo Schematic Cross-section
2. Retortillo Schematic Cross-section 
3. Retortillo Exploration Potential
3. Retortillo Exploration Potential 
4. Drilling Plan Highlighting Extension of Zona 7 Mineralisation
4. Drilling Plan Highlighting Extension of Zona 7 Mineralisation 
5. Zona 7 Schematic Cross Section
5. Zona 7 Schematic Cross Section 

Retortillo is 100% owned by Berkeley and has resources totalling 16.2 million tonnes at 376ppm U3O8 for a total of 13.4Mlbs (6.1Kt) U3O8.

Mineral Resources as at September 2013 (using 200ppm U3O8 Cutoff)

Deposit

Resource Category

Tonnes
(Mt)

U3O8 Grade
(ppm)

U3O8
(t)

U3O8
(Mlbs)

Retortillo

Indicated

14.4

378

5,425

12.0

 

Inferred

1.8

359

650

1.4

 

Total

16.2

376

6,075

13.4

Berkeley has completed a positive PFS on the integrated development of Retortillo and Alameda which confirmed technical and economic viability of the Project. The PFS was based on open pit mining and heap leaching at Retortillo and Alameda, a centralised process plant at Retortillo, and a remote ion exchange operation at Alameda, with loaded resin trucked to the centralised plant for final extraction and purification.

Retortillo

The Retortillo deposit was previously drilled by the JEN and ENUSA and Berkeley has undertaken resource infill and extension RC and diamond drilling.

The original JEN drilling was restricted to the north western end of the deposit on a 50m x 50m grid. After some verification drilling, ENUSA explored to the southeast and was successful in defining significant resource extensions. Berkeley has undertaken a number of phases of drilling aimed at verification of the previous drill results on selected traverses; infill drilling to achieve a higher confidence in the resource, further extension drilling to the southeast, and targeted drilling to test geological continuity and to test for structural and lithological controls, particularly along the northern and southern limits of the resource.

This drilling has defined the limits of the deposit, established geological continuity of mineralisation and provided insights into the styles of uranium mineralisation and possible controls. Berkeley's verification drilling was successful in improving the average thickness of the mineralisation and revealed some inconsistencies in the historical data. A check on the historical data combined with the additional drilling has led to a validated database being created, which allowed for the update of the resource estimates.

Retortillo consists of two main areas of mineralisation with a total strike length of almost 3km hosted by Ordovician metaphyllite. The mineralisation has widths of 200m to 600m and ranges in thickness from 2m to 30m. Tertiary sediments cover the south eastern part of the deposit varying from 5m to 30m in depth and generally thickening towards the southeast.

The mineralised envelope is generally sub-horizontal and the mineralisation is contained within a stockwork of veins. The uranium mineralisation appears to be associated with the presence of sulphides within the partially weathered zone and the base of mineralisation is associated with the base of partial weathering which locally deepens along structures. Mineralisation is associated with hydrothermal sericite, pyrite +/- chlorite alteration.

The primary uranium mineralisation consists of pitchblende/uraninite, coffinite and black oxides incorporated into the main steeply dipping schistosity and along fracture planes. A secondary enrichment of dominantly autunite and minor torbernite occurs as an upper sub-horizontal layer. The pitchblende/uraninite is often seen coating pyrite grains or within fractures in pyrite.

A second zone of mineralisation (previously known as Santidad) is located within the same stratigraphic sequence of regionally and thermally metamorphosed Ordovician metaphyllite and is located 3km to the northwest of Retortillo. The metaphyllite contains numerous granitic and pegmatitic sills and anomalously large chiastolitic blades of andalusite, indicating closer proximity to the main granodiorite complex which outcrops to the southwest. There is no Tertiary cover present in this area.

Testing of this radiometric anomaly by Berkeley with RC and diamond drilling discovered shallow uranium mineralisation over a strike length of 3.0km with widths from 100m to 200m and thickness ranging from 2m up to 20m.The resource remains open along strike to the northwest.

The uranium mineralisation occurs within a sub-horizontal layer predominantly within the partially oxidised zone, close to the interface with fresh rock.

Permitting

A major permitting milestone was achieved in April 2014 with the grant of the Exploitation Concession (‘Mining Licence') for Retortillo by the Regional Government of Castilla and León (refer ASX announcement dated 24 April 2014).

The grant of the Mining Licence for Retortillo is a major milestone for the Company and follows the approval of Exploitation and Reclamation and Closure Plans for the proposed mining operation submitted by Berkeley, and the completion of a number of studies and technical review sessions with relevant government agencies. The granting of the Mining Licence has also taken into account the prerequisite approval of the Company's Environmental and Social Impact Assessment (‘ESIA') by the environmental authorities (the Environmental Licence for Retortillo was awarded in October 2013), and the favourable recommendation report issued by the Nuclear Safety Council.

The Mining Licence is valid for an initial period of 30 years and may be renewed for two additional periods of 30 years. It covers an area of 25.2km2 and includes the entire area containing the Retortillo Mineral Resource Estimate.

With the grant of the Mining Licence, the approval processes associated with other key permits including the Initial Authorisation of the process plant as a radioactive facility and the Exceptional Authorisation for Land Use (application for reclassification from rural to industrial use) of the affected surface land area at Retortillo, may now be finalised.

Retortillo Satellite Deposits

Other Satellite deposits within the Retortillo area include:

  • Zona 7
  • Las Carbas
  • Cristina
  • Caridad,
  • Villares,and
  • Villares North.
Mineral Resources as at September 2013 (using 200ppm U3O8 Cutoff)

Deposit

Resource Category

Tonnes
(Mt)

U3O8 Grade
(ppm)

U3O8
(t)

U3O8
(Mlbs)

Zona 7

Inferred

3.9

414

1,613

3.6

Las Carbas

Inferred

0.6

443

262

0.6

Cristina

Inferred

0.8

460

364

0.8

Caridad

Inferred

0.4

382

165

0.4

Villares

Inferred

0.7

672

480

1.1

Villares North

Inferred

0.3

388

100

0.2

Retortillo Satellite Deposits

Total

6.7

447

2,984

6.6

These deposits are located between 6km and 12km north and northwest of Retortillo.

The host rocks are typically Precambrian chlorite-sericite metaphyllite, slate, quartzite and conglomerate. The uranium mineralisation appears to be similar to that at Retortillo and is controlled by lithology, structure and possible supergene enrichment. Berkeley has completed a significant amount of drilling to define these resources and further drilling will test for potential extensions to the resources.

Exploration Potential

Substantial exploration potential remains within the tenements held by Berkeley in the Retortillo area. Berkeley conducted a helicopter-borne radiometric and magnetic survey over its tenements in the Retortillo area in 2007. This survey confirmed the known anomalies and demonstrated the potential to add additional uranium resources in outcropping and covered areas in proximity to existing resources. Some of the anomalies remain untested.

To the north of Retortillo the radiometric survey defined an anomaly in the Villares area where JEN and ENUSA have previously drilled and intersected uranium mineralisation. The potential of the airborne radiometric anomalies at Villares Zona 19 and Zona 4 was confirmed with a ground radiometric survey and drilling in 2012 confirmed the presence of shallow high grade uranium mineralisation. Resource estimates have now been established for Villares (Zona 19) and Villares North (Zona 4).

The radiometric survey also significantly enlarged the target area associated with known uranium mineralization at Zona 7 and at two previously mined areas, Caridad and Cristina. At Zona 7 the radiometric anomaly continues for several kilometres to the northeast along the granite sediment contact and appears to link to the Cristina deposit as well as extending to the southwest towards the Las Carbas resource.

An 18 hole, 1,133 metre RC drill program was carried out on an approximately 400 metre by 100 metre grid to test the potential extension of Zona 7 to the southwest in mid-2013. Assay results confirmed that the Zona 7 mineralisation extends a further 1,200 metres to the southwest of the current resource area. The drilling essentially doubled the strike extent of the mineralised zone and it remains open. Significant high grade intersections have been recorded at shallow depths (from 9 metres to a maximum depth of 84 metres), with thicknesses up to 29 metres. Select intercepts include:

 

Hole No.Down Hole InterceptFrom Depth (Down Hole)
Z7R-084 29m @ 3,391 ppm U3O8 9m
Z7R-088 17m @ 1,260 ppm U3O8 37m
Z7R-089

4m @ 2,365 ppm U3O8

15m @ 1,392 ppm U3O8

2m @ 2,759 ppm U3O8

39m

63m

82m

Z7R-087 25m @ 683 ppm U3O8 27m
Z7R-090 13m @ 1,161 ppm U3O8 17m
Z7R-085 16m @ 764 ppm U3O8 33m

More details of the Zona 7 drilling results are given in the ASX Release of 7 August 2013 titled High Grade Mineralisation Intersected in Drilling at Retortillo Satellite Deposit.

A follow up drill program at Zona 7, which will comprise approximately 600m of diamond core and 2,500m of reverse circulation (‘RC') drilling, is aimed at infilling the zone of mineralisation defined by the 2013 drilling and extending it further to the south-west. The program has been designed to close the existing drill pattern down to a notional 100m by 100m pattern to facilitate the estimation of a revised Inferred Mineral Resource for the prospect. The drilling will be conducted during May and June 2014.

The Retortillo stratigraphy remains relatively untested for approximately 3.5km along strike to the northwest, before it is truncated by granite and much of this extension is covered by Tertiary.

To date, all the defined resources have been discovered in areas of outcrop. Exploration will also investigate the potential of resources existing under the Tertiary cover and exploration techniques are being investigated to assist in defining target areas.

The information in this section of the website that relates to Exploration Results and Mineral Resources is based on information compiled by Craig Gwatkin, who is a Member of The Australian Institute of Mining and Metallurgy and was an employee of Berkeley Resources Limited. Mr. Gwatkin has sufficient experience which is relevant to the style of mineralisation and type of deposit under consideration and to the activity which he is undertaking to qualify as a Competent Person as defined in the 2004 Edition of the ‘Australasian Code for Reporting of Exploration Results, Mineral Resources and Ore Reserves’. Mr. Gwatkin consents to the inclusion in the report of the matters based on his information in the form and context in which it appears. This information was prepared and first disclosed under the JORC Code 2004. It has not been updated since to comply with the JORC Code 2012 on the basis that the information has not materially changed since it was last reported.