Don Sixto
Overview
As a result of political developments in the Mendoza Province, Argentina, in 2007, the development of the advanced Don Sixto Gold Project was put on hold. Exeter/Extorre filed action in the Mendoza Supreme Court to have this anti-mining legislation declared unconstitutional and has been working with authorities in Mendoza, and with representatives of other mining companies, to effect legislative change. With the upcoming election and some changes in sentiment in the province, Extorre hopes to begin work at Don Sixto again in 2012.
The Don Sixto Project contains over 60,000 meters of drilling, and preliminary development studies have been completed. During 2010, these studies will be updated using more appropriate vein modelling and grade estimating techniques than those previously employed by independent consultants, Hellman and Schoffield. This work will be completed by Cube Consulting, the Perth-based consulting group responsible for preparing the updated mineral resource estimate for the Cerro Moro Project. Thenceforth economic studies will be updated internally, using current metal prices, and updated infrastructure and mining costs. Should these studies indicate positive economics, the company may then focus on working to permit the Project, following construction of the Cerro Moro Project.
Extorre presently has the right to 100% of the Don Sixto Project, subject to a royalty on future production capped at US$1.0 million.
Project Location
The Don Sixto Project is located in the southern part of the Mendoza Province, central-western Argentina. The property lies at an altitude of 1200 meters, and the arid character of the area allows good year-round access. The property is also located close to infrastructure and basic goods and services. The property is controlled through an option agreement between an Argentinean vendor and Cognito Limited ("Cognito"), a 100%-Extorre owned subsidiary in Argentina, in which Cognito has the right to acquire the Don Sixto Project.
Land Situation
Extorre presently controls 100 square kilometers of mining tenements at the Don Sixto Gold Project through the Cognito option for the acquisition of Don Sixto. In addition, Cognito has signed options to acquire from Argentine vendors two additional blocks of tenements around Don Sixto, the first covering 176 square kilometers and the second covering 81.5 hectares. Cognito has also applied for a cateo covering 100 square kilometers to the immediate south of the Don Sixto deposit.
Early in 2006, the surface rights for the area at Don Sixto that is contemplated for mine development were purchased from local land holders. The acquisition of the "El Pantanito" farm will facilitate the transition of the project from exploration to development, and provides certainty for the landowners most affected by it (as the company is required to build a house for the previous owners of “El Pantanito” at another location to complete contractual requirements of the purchase).
Image displaying outline of "El Pantanito" farm
Geology & Mineralisation
The Don Sixto Project lies within a north-westerly trend of steeply dipping and concordant units of rhyolitic (ignimbrites) and sedimentary (volcaniclastics) units belonging to the Permo-Triassic Choiyoi Formation. Gold mineralisation occurs as fine dissemination and blebs in north to north-westerly quartz veins and quartz replacement zones in the ignimbrite and volcaniclastics. The style of mineralisation is essentially a gold-silver, silica-sericite/illite-adularia low sulphidation epithermal system with low pyrite (<2%) and minor clay alteration.
Don Sixto Project, Central Vein Zone - Labio vein
Mineral Resources
An updated mineral resource estimate for the Don Sixto Project was prepared by independent consultants Hellman and Schofield in 2007. Geological and assay data from approximately 57,000 m of drilling and 4,037 m of sawn channel samples were incorporated into this mineral resource estimate, with the results - calculated at cut-off grades of 0.5 gram/tonne (“g/t”) and 1.0g/t, and listed by prospect - tabulated below:
Table 1: Don Sixto Gold Resource Estimates at a 0.5 g/t gold cut-off
| MEASURED | INDICATED | MEASURED & INDICATED |
INFERRED | |||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Mt | g/t | koz Au |
Mt | g/t | koz Au |
Mt | g/t | koz Au |
Mt | g/t | koz Au |
|
| Cuello | 1.49 | 1.83 | 88 | 3.80 | 1.39 | 170 | 5.29 | 1.51 | 258 | 1.85 | 1.20 | 71 |
| Ojo | 1.43 | 1.63 | 75 | 1.49 | 1.25 | 60 | 2.92 | 1.44 | 135 | 0.71 | 1.05 | 24 |
| Luna | 1.71 | 1.58 | 87 | 4.51 | 1.23 | 178 | 6.22 | 1.32 | 265 | 1.79 | 1.07 | 61 |
| Mandibula | 2.77 | 1.00 | 89 | 1.77 | 1.09 | 62 | 4.54 | 1.03 | 151 | 4.24 | 0.93 | 126 |
| CVZ* | 0.75 | 2.51 | 61 | 0.76 | 2.24 | 55 | 1.51 | 2.38 | 116 | 0.35 | 1.52 | 17 |
| Cachete | - | - | - | - | - | - | - | - | - | 0.35 | 3.08 | 35 |
| TOTAL | 8.15 | 1.52 | 400 | 12.33 | 1.32 | 525 | 20.48 | 1.40 | 925 | 9.29 | 1.12 | 334 |
Table 2: Don Sixto Gold Resource Estimates at a 1.0 g/t gold cut-off
| MEASURED | INDICATED | MEASURED & INDICATED |
INFERRED | |||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Mt | g/t | koz Au |
Mt | g/t | koz Au |
Mt | g/t | koz Au |
Mt | g/t | koz Au |
|
| Cuello | 0.84 | 2.68 | 73 | 1.87 | 2.09 | 125 | 2.71 | 2.27 | 198 | 0.84 | 1.78 | 48 |
| Ojo | 0.79 | 2.37 | 60 | 0.62 | 2.03 | 40 | 1.41 | 2.22 | 101 | 0.20 | 1.95 | 13 |
| Luna | 0.91 | 2.35 | 68 | 1.83 | 2.01 | 118 | 2.73 | 2.12 | 186 | 0.52 | 2.02 | 33 |
| Mandibula | 0.90 | 1.63 | 47 | 0.66 | 1.73 | 37 | 1.56 | 1.67 | 84 | 1.10 | 1.60 | 57 |
| CVZ* | 0.46 | 3.67 | 54 | 0.46 | 3.24 | 48 | 0.92 | 3.45 | 102 | 0.15 | 2.62 | 13 |
| Cachete | - | - | - | - | - | - | - | - | - | 0.33 | 3.39 | 36 |
| TOTAL | 3.90 | 2.41 | 302 | 5.44 | 2.11 | 368 | 9.34 | 2.23 | 670 | 3.14 | 1.98 | 200 |
Notes: (*) CVZ or Central Vein Zone comprises the Labio East, Labio West, Labio South and Mercedes prospects.
“Mt” represents million tonnes, and “koz” represents thousand ounces.
The mineral resource estimates for the Cuello, Luna, Ojo, Mandibula and the Central Vein Zone prospects were made by Hellman & Schofield (“H&S”), of Sydney, Australia following a three week visit to Mendoza at the end of April 2007. The visit, by two representatives, included a two week site visit and validation of the Exeter database, supporting information, and 3-D geological and structural models.
H&S utilised the Multiple Indicator Kriging (“MIK”) method, which estimates the proportion and grade of mineralization for an assumed selective mining unit (“SMU”) within a larger panel (or “block”) for a range of cut-off grades. The deposit is divided into panels (or “blocks”) and in the case of Don Sixto, a panel size of 5 m wide x 25 m long x 10 m high was deemed suitable for the data spacing. Within these panels, two selective mining unit (“SMU”) sizes were utilised: for vertical to near vertical domains, an SMU of 2.5 m width x 5 m length by 5 m height was used and for flat to shallow dipping domains an SMU of 2.5 m width x 5 m length by 2.5 m height was used. The estimates include the dilution incurred when mining the resources at the assumed SMU. This methodology generally results in a resource estimate of higher tonnes and lower grade than less conservative/more standard resource estimation techniques. However, total ounces estimated utilizing the H&S MIK method generally equate to total ounces estimated using less conservative techniques.
The Cachete prospect resource remains unchanged from the previous resource estimation exercise, which was calculated internally by Exeter (in 2005) utilising a manual polygonal cross sectional method of estimation.
2010 Exploration Program
No exploration and/or development activities are scheduled to be undertaken at the Don Sixto project during 2010. However, Perth-based Cube Consulting has been commissioned to update the 2007 mineral resource estimate for Don Sixto using more appropriate vein modelling and grade estimation techniques than were previously employed.
43-101 Report:
Sep, 2007 (Details 5.9 MB - PDF)
July, 2005 (Details 5.9 MB - PDF)
November, 2004 (Details 3.4 MB - PDF)
October, 2002 (Details 1.2 MB - PDF)