PROJECTS - Chile
Caspiche
The Caspiche Project is located in the Maricunga Belt of Chile, a world class gold province. The property is 10 kilometres north of Barrick and Kinross Gold’s Cerro Casale gold-copper deposit and 15 kilometres due south of Kinross Gold’s Refugio Mine. The new Volcan gold deposit owned by Andina is 35 kilometres noth northeast of Caspiche;
- Cerro Casale Gold-Copper Deposit, 22.9 million ounces of gold at a grade of 0.69 grams per tonne (“g/t”) and 5,800 million pounds of copper grading 0.25% (Kinross NI 43-101 Report, August 22nd 2006).
- Refugio Gold Mine, 5.4 million ounces of gold at a grade of 0.76 g/t (Kinross NI 43-101 Report, December 31st 2006)
- Volcan Deposit, 6.9 million ounces gold at a grade of 0.55 g/t (Andina 43-101 Report, October 2007)
Please Click here to view the latest 43-101 on Caspiche 6.23MB PDF
Figure 1: Southern Maricunga Belt Mineral Deposits on Satellite Imagery.
In 2007 Exeter reported an important gold mineralized intersection of 304 metres (1,003 ft) grading 0.9 grams/tonne (“g/t”) gold (0.026 oz/ton) from drill hole CSR-013. This was the first hole drilled by Exeter to test the porphyry potential of the property. The hole reached 344 meters which was the ultimate capacity of the drill rig. More recently hole CSR-016 intersected 719 meters grading 1.0 g/t (0.032 oz/ton) gold and 0.38% copper.
The Agreement
In October of 2005 Exeter signed an option agreement with Anglo American Chile Limitada and Mantos Blancos S.A. (collectively "Anglo American") over a number of prospective gold projects in the Maricunga metallogenic belt of Chile, one being the Caspiche Project. The terms of the agreement provide for increasing annual drilling and exploration commitments over five years. Once Exeter has spent a total of US$2.55 million, and completed 15,500 metres drilling, it will have earned a 100% interest. Anglo American will be entitled to a 3% net smelter return from production.
The Target
Exeter’s target at Caspiche is analogous to that at Cerro Casale, and comprises:
- a near surface potentially heap leachable gold “blanket” ore body, underlain by
- a gold-copper “porphyry” ore body that would require conventional floatation to produce a saleable gold-copper concentrate.
Exeter Exploration
Exeter commenced field exploration on the optioned Anglo American Maricunga projects in November, 2005 - following a compilation of existing data. All properties were visited and reconnaissance exploration rated the prospects according to their apparent potential. This led to the identification of the Caspiche property as the best opportunity for Exeter.
Caspiche has a combined area of 1262 hectares. From a data review combined with surface mapping and sampling Exeter identified three target zones on the property: (1) Caspiche Central Epithermal Mineralization zone with epithermal gold potential in the central west of the property, (2) Caspiche Central Porphyry - a porphyry gold-copper system beneath the Caspiche Central Epithermal Mineralization, and (3) Caspiche III - a zone of epithermal gold-silver mineralization in the east of the property.
Figure 2: Caspiche Property, Principal Prospects and Exeter Drill Holes.
In 2006 Exeter undertook detailed geophysical surveying aimed at identifying resistive anomalies (Controlled Source Audible Magneto Tellurics, CSAMT), and reprocessed airborne magnetic data from a helicopter survey completed by previous explorers. Geological mapping and geochemical sampling were also conducted on the large target areas.
Initial exploration was focused on potential for high sulphidation epithermal style mineralization on the Caspiche III target. Drill targets were selected on the basis of mapped prospective geology combined with high resistivity geophysical targets. High resistivity equates to strong silicification which is commonly associated with high sulphidation epithermal gold-silver deposits. Later exploration efforts were directed to the porphyry potential at Caspiche Central with one hole, CSD-018, aimed at a buried geophysics target to the northeast of the Caspiche Central target. To date Exeter has drilled 26 holes. The final two holes were stopped before reaching target depths due to weather on site. They will be completed next season.
Table 1: Drill Collar Details for Holes Drilled on the Caspiche Property by Exeter.
| Hole | Easting | Northing | Elevation | Depth (m) | Azimuth | Dip | Location |
|---|---|---|---|---|---|---|---|
| CSR-001 | 473127 | 6937334 | 4560 | 94 | 0 | -70 | Surveyed |
| CSR-001A | 473125 | 6937336 | 4560 | 238 | 0 | -70 | Surveyed |
| CSR-002 | 473350 | 6937487 | 4610 | 187 | 20 | -70 | Surveyed |
| CSR-003 | 473682 | 6937473 | 4635 | 250 | 0 | -70 | Surveyed |
| CSR-004 | 472930 | 6937730 | 4630 | 185 | 0 | -70 | Surveyed |
| CSR-005 | 471910 | 6938450 | 4540 | 300 | 355 | -70 | Surveyed |
| CSR-006 | 474140 | 6937200 | 4680 | 264 | 0 | -70 | Surveyed |
| CSR-007 | 472595 | 6938095 | 4545 | 300 | 0 | -90 | GPS |
| CSR-008 | 474110 | 6937100 | 4680 | 300 | 0 | -70 | GPS |
| CSR-009 | 473120 | 6937580 | 4620 | 300 | 25 | -60 | GPS |
| CSR-010 | 473270 | 6937470 | 4593 | 260 | 0 | -60 | GPS |
| CSR-011 | 473650 | 6937340 | 4608 | 186 | 0 | -60 | GPS |
| CSR-012 | 473950 | 6937070 | 4655 | 340 | 0 | -60 | GPS |
| CSR-013 | 470870 | 6937370 | 4370 | 344 | 60 | -60 | GPS |
| CSD-014 | 470923 | 6937063 | 4412 | 741 | 60 | -60 | GPS |
| CSD-015 | 470624 | 6937351 | 4333 | 1001 | 60 | -60 | GPS |
| CSD-016 | 470816 | 6937220 | 4370 | 792 | 60 | -60 | GPS |
| CSR-017 | 470504 | 6937285 | 4327 | 73 | 60 | -60 | GPS |
| CSD-018 | 470275 | 6937692 | 4268 | 704 | 60 | -65 | GPS |
| CSR-019 | 471118 | 6937388 | 4403 | 240 | 60 | -60 | GPS |
| CSR-020 | 470722 | 6937509 | 4362 | 250 | 60 | -60 | GPS |
| CSR-021 | 470903 | 6936864 | 4430 | 152 | 60 | -60 | GPS |
| CSR-022 | 470867 | 6937146 | 4386 | 231 | 60 | -60 | GPS |
| CSR-023 | 470795 | 6936993 | 4390 | 200 | 60 | -60 | GPS |
| CSD-024 | 470948 | 6937602 | 4400 | 750 | 250 | -65 | GPS |
| CSD-025 | 471010 | 6937460 | 4396 | 336 | 240 | -65 | GPS |
| CSD-026 | 471167 | 6937313 | 4400 | 209 | 240 | -60 | GPS |
Note: CSR = Reverse Circulation hole and CSD = Diamond hole.
Drilling – Caspiche Central Porphyry Target
In the 1990’s Newcrest tested the porphyry potential at Caspiche Central with three drill holes. The area of the drilling is entirely covered by colluvium material.
Table 2: Newcrest Caspiche Central Porphyry Mineralized Holes (not NI43-101 compliant).
| Hole | From (m) |
To (m) |
Width (m) |
Gold g/t |
Copper % |
|---|---|---|---|---|---|
| CDH-2b | 64 | 330 | 266 | 0.47 | 0.22 |
| including | 126 | 154 | 28 | 0.9 | 0.43 |
| and | 214 | 274 | 60 | 0.6 | 0.27 |
| CDH-03 | 28 | 326 | 298 | 0.54 | 0.17 |
| including | 28 | 58 | 30 | 0.7 | 0.01 |
| and | 222 | 326 | 104 | 0.7 | 0.23 |
| CDH-12 | 16 | 326 | 310 | 0.3 | 0.08 |
Exeter drilled hole CSR-013, the final hole for the 2006-2007 season into the area prospective for porphyry style mineralization at Caspiche Central. This was the first hole to be drilled on this target by Exeter and was sited over a pronounced geophysical anomaly (Induced Polarization Chargeability) that had been delineated by Newcrest. The anomaly had been partly tested by Newcrest drill holes, CDH-2b and CDH-3, although it was clear to Exeter that there remained significant potential for a deposit the size of the nearby Cerro Casale or Refugio deposits.
CSR-013 intersected a wide zone of mineralization, at a higher grade, than Newcrest’s previous holes, 304 metres (1,003 ft) grading 0.9 g/t gold (0.026 oz/ton), from a down hole depth of 40 metres. It was terminated in economic tenor mineralization at the final drilling capability of the RC rig. The gold porphyry target remained open to depth as well as to the north, south, east and west. Copper appeared at a down hole depth of 214 metres, indicating potential for an upper “leachable” gold section (devoid of copper) that averaged 0.9 g/t gold.
Exeter contracted Major Drilling to provide two diamond drill rigs for the 2007-2008 season. A third reverse circulation drill rig was also contracted for a period principally to assist with testing the upper gold blanket. The first hole, CSD-014, was collared 300 meters to the south of CSR-013. The new hole intersected an upper oxide silica cap mineralized zone from 0 to 148 meters, followed by 593 meters of porphyry stockwork mineralization that continued to the end of the hole at 744.7 meters. The potential “leachable” near surface gold zone in CSD014 is 148 meters in downhole length at a grade of 0.57 g/t gold, which includes 60 meters at a grade of 0.7 g/t gold.
Diamond drill hole CSD-015 was collared 400 meters to the northwest of hole CSD-014 and 250 meters to the west of CSR-013. Assays for CSD-015 returned 56.05 meters at a grade of 0.0.35 g/t gold in oxide material, from a depth of 57.95 meters. This interval was followed by 887.4 meters at a grade of 0.62 g/t gold and 0.27 % copper in the sulphide zone.
Diamond drill hole CSD-016 was drilled 200 meters northeast of CSD-014 and 200 meters southwest of CSD-015. The hole intercepted 718.75 meters (2,358 feet) at a grade of 1.0 g/t gold and 0.38% copper, from a depth of 73 meters. The upper gold blanket component was 92 meters at a grade of 0.41 g/t gold from 73 meters downhole. The lower sulphide component was 626.75 meters grading 1.1 g/t gold and 0.43 % copper. The hole ended at the limit of the drills capacity of 791.75 meters. The final 2.75 meters (9 ft) of drill core recovered from the hole assayed 0.74 g/t (0.021 oz/ton) gold and 0.35% copper.
Table 3: Caspiche Central Drill Hole Mineralised Intercepts
| HOLE | OXIDE ZONE (Epithermal and Porphyry) | SULPHIDE ZONE (Porphyry) | ||||||||
|---|---|---|---|---|---|---|---|---|---|---|
| From | To | Width | Gold | Copper | From | To | Width | Gold | Copper | |
| (m) | (m) | (m) | (g/t) | (%) | (m) | (m) | (m) | (g/t) | (%) | |
| CSR-013 | 40 | 214 | 174 | 0.88 | 0.01 | 214 | 344 | 130 | 0.87 | 0.22 |
| CSD-014 | 0 | 148 | 148 | 0.57 | 0.02 | 148 | 740.7 | 592.7 | 0.44 | 0.25 |
| CSD-015 | 58 | 114 | 56.1 | 0.35 | 0.02 | 114 | 1001.4 | 887.4 | 0.62 | 0.27 |
| CSD-016 | 73 | 165 | 92 | 0.41 | 0.01 | 165 | 791.8 | 626.8 | 1.08 | 0.43 |
To view assays and summary photo-geological logs please click on the links below:
CSR-013
CSD-014
CSD-015
CSD-016
To review Exeters Latest NI43-101 update report on Caspiche click on the Link below:
TECHNICAL REPORT & PROPOSED EXPLORATION FOR THE CASPICHE PROJECT, 26 APRIL, 2008 6.23MB PDF
Figure 3: Exeter Caspiche Central Drill Holes.
Caspiche Central Mineralization Model
Two dominant mineralization styles are observed on the Caspiche Central target being (1) a Near Surface Potential Heap Leachable Oxide Gold Rich Epithermal Zone and (2) a Lower Porphyry Stockwork High Gold/Low Copper Mineralization.
The Near Surface Potential Heap Leachable Oxide Epithermal Mineralization is exposed at two localities. These outcrops first drew attention to the presence of gold mineralization on the property. Gold in oxidised rock was also intersected in drill holes beneath the widespread alluvium. The epithermal mineralization comprises intense silica flooding with abundant alunite, kaolin and pyrophyllite.
Porphyry Stockwork High Gold/Low Copper Mineralization does not outcrop on the property, only having been intersected by drilling. Three alteration styles dominate in the porphyry environment - an inner Potassic alteration, an outer Phyllic alteration and a Retrograde Intermediate Argillic alteration that partially overprints both the earlier phases. The Potassic alteration is best defined by the presence of hydrothermal biotite replacing mafic minerals and disseminated and vein magnetite, along with small amounts of pyrite. Phyllic alteration is defined by abundant sericite along with clay and a slight increase in the amount of pyrite. The Retrograde Intermediate Argillic alteration overprints earlier Potassic alteration converting earlier biotite to chlorite and magnetite to specular haematite, along with depositing disseminated clay minerals.
Mineralization is associated with silicification in the Epithermal zone and quartz stockwork veining in the Porphyry environment. Further work is required to determine the controls on high and low grade mineralization. Oxide leaching is noted down to around 150 meters depth in the holes drilled to date.
Figure 4: Schematic Model for Mineralization on the Caspiche Central Gold-Copper Deposit.
The geology and mineralization observed at Caspiche appears to be characteristic for Maricunga porphyries and is well documented in the literature for other deposits in this region. Caspiche mineralization appears to be very similar to the Cerro Casale deposit located 10 kilometres to the south based on the alteration, mineralogy and the retrograde Intermediate Argillic Alteration overprinting the earlier Potassic stockwork quartz-magnetite core. The wide stockwork zone intersected by holes CSD-014, CSD-015 and CSD-016 indicates that Caspiche is another similarly large Gold-Copper Porphyry deposit and as such it has very significant exploration potential.
Future Exploration
The objective of Exeter’s 2007-2008 drilling season has been to define the broad limits of porphyry mineralization through wide spaced step out drilling. Once the approximate limits are established infill drilling will be required to develop the required knowledge base for the determination of resources for both oxide and sulphide ore types.
Property wide exploration is also underway using additional geophysical programs to assist in defining the dimensions of the porphyry system, and to discover additional mineralization centres. Exeter expects to have at least 4 drill rigs operating on the project in the 2008-2009 season that commences in October.
Drilling - Caspiche III Epithermal Target
Exeter commenced drilling on the Caspiche project early in 2007 with the aim of testing the Caspiche III epithermal target with 7 drill holes. Results suggested that mineralization was deeper than expected, so a follow-up drill program was carried out to test potential for mineralisation nearer to surface. Holes drilled in the later program intersected significant widths of mineralisation but again there was considerable cover, suggesting a probable difficulty in establishing the near term viability of the Caspich III epithermal target.
Drilling confirmed the presence of a high-sulphidation epithermal gold system at Caspiche III. Mineralization is interpreted to lie within flat lying replacement zones that are probably related to a nearby intrusive body which has yet to be intersected by drilling.
Table 4: Significant Exeter Drill Intercepts from the Caspiche III Epithermal Gold + Silver Target
| Hole | From (m) |
To (m) |
Width (m) |
Gold g/t |
Silver g/t |
|---|---|---|---|---|---|
| CSR-002 | 52 | 76 | 24 | 1.1 | 23 |
| CSR-002 | 172 | 178 | 6 | 1.7 | 16 |
| CSR-006 | 144 | 166 | 22 | 1.5 | 1.6 |
| CSR-008 | 42 | 58 | 16 | 1.3 | 5 |
| CSR-010 | 166 | 202 | 36 | 1.3 | 26 |
| CSR-011 | 96 | 108 | 12 | 1.2 | 4 |
| CSR-012 | 94 | 110 | 16 | 2.1 | 2 |
Table 5: Significant Results from Previous Drilling on Epithermal Targets (not 43-101 compliant)
| Hole | From (m) |
To (m) |
Width (m) |
Gold g/t |
Silver g/t |
|---|---|---|---|---|---|
| CDH-05 | 0 | 126 | 126 | 0.7 | 6 |
| CDH-05 | 126 | 200 | 74 | 0.5 | 2 |
| CDH-14 | 92 | 150 | 58 | 0.5 | 25 |
| SHC-05 | 2 | 48 | 46 | 1 | 6 |
| SHC-07 | 2 | 50 | 48 | 0.5 | 10 |
| SHC-10 | 2 | 50 | 48 | 0.7 | 1 |
| SPC-01 | 26 | 58 | 32 | 0.7 | 13 |
| SPC-05 | 2 | 102 | 100 | 0.5 | 1 |
Quality Control and Assurance
Drill widths presented above are drill intersection widths and may not represent the true widths of mineralization. Gold assay results presented are preliminary and have not been calculated using a gold cut-off grade, or with any cutting of high grades.
All diamond drill core samples are split on regular two metre intervals and represent either sawn half HQ-size or NQ-size core. Gold samples were prepared and assayed by fire assay (50 gram charge) whilst copper was assayed with a four acid digestion and atomic absorption spectroscopy (AAS). The primary laboratory is ALS Chemex in Chile, an ISO-9001:2000 certified laboratory. Standard, blank and duplicate samples are used throughout the sample sequence as checks for the exploratory reverse circulation and diamond drilling.
Glen Van Kerkvoort, Exeter’s Chief Geologist and a “qualified person” within the definition of that term in National Instrument 43-101, Standards of Disclosure for Mineral Projects, has supervised the preparation of the technical information contained in this news release.
43-101 Report:
26 April, 2008 (Details 6.23 MB - PDF)
24 December, 2007 (Details 6.72 MB - PDF)
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