In July 2004 Gitennes Exploration Inc. (TSX.V: GIT) entered into an option agreement with Inmet Mining Corp. to acquire a 2,300 hectare property known as Tucumachay. The property is located in the Andes Mountains 160 km east of Lima. Access is by road - about an 8 hour drive from Lima and approximately 3 hours from Huancayo.. Terms of the option agreement are detailed in the Company's July 6, 2004 news release.
Gitennes is exploring for gold at the Tucumachay Project in central Peru. Since announcing the transaction in June 2004, Gitennes has transformed a very raw prospect with a good showing and intriguing geology into a property with multiple surface showings and bulk-tonnage targets. Mineralization at Tucumachay is similar to that found in Carlin-style deposits.
Since the start of exploration in mid-2004, crews have collected over 1,830 rock samples (of which 1,700 are chip channel samples over an aggregate distance of over eight kilometres) as well as 1050 soil samples, and 367 MMI samples, completed 25 line kilometres of I.P. and VLF-EM surveys, and cored 1,984 metres in 19 holes. Based on the results to date, it appears that the La Nariz area (Sinkhole-Leonardo-Guapita) offers the best potential for proving-up a large tonnage, near-surface zone, followed by the Cerro Oeste – Greg and Encantada areas.
A number of showings have been found in outcrop, through a combination of systematic rock-chip sampling and soil geochemical surveys. Gold showings can be described under two generalized headings: (1) lower-grade in fractured and collapsed limestone beds, near corridors of faulting, and (2) higher grade in silicified (jasperoid) carbonaceous limestone and mudstone. The two styles are spatially linked in the La Nariz area, where fracture and intraformational breccia mineralization can be traced along corridors of cross-fractures outwards (and stratigraphically upwards) into domains of silicified breccia then into massive jasperoid mantos. The scale of these “systems” is large (200 to 600 m in length) and the grades are respectable.
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Figure at left shows air photo of fold-thrust complex, gold showings (yellow), zinc (orange). La Nariz is southern area – the “nose” of the fold. Includes Leonardo, Sinkhole, Cliff, Guapita prospects. Other zones are Encantada and Cerro Oeste-Greg. Scale: 7 km top-bottom, 5 km across.
Figure below is the working model for mineralization at La Nariz.
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Click on the images to enlarge
Following are examples of surface outcrop and trench results. All are chip-channel or panel sample:
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Target
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Sample length (metres)
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Gold (g/t)
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Notes
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Target
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Sample length (metres)
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Gold (g/t)
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Notes
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Sinkhole
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24.0
16.0
54.0
12.0
40.0
16.0
40.0
8.0
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1.15
0.52
0.85
0.93
0.44
0.88
0.98
0.66
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250 by 400 metre area of highly fractured and brecciated dolomite.
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Leonardo
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3.6
8.0
12.1
54.0
10.1
3.6
5.9
10.0
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1.70
1.46
1.05
0.85
5.23
2.23
6.02
5.50
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Scattered jasperoid in o/c at contact. Sits “on top of” the Sinkhole breccias.
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Cliff Inmet’s original showing.
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3.0
11
6.0
5.0
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5.70
1.40
2.10
0.70
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120 by 50 metre area of siliceous fractures and mantos.
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La Guapita
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12.0
27.0
10.0
17.0
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0.92
0.82
1.12
0.61
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Intraformational Breccia. Vertical chips up cliff face.
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Based on work to date, including drilling, we feel that the 7,200 m2 La Nariz area (1,200 metres long and 200 to 800 metres wide) that encompasses these showings could host a large flat-lying, near-surface zone of 0.8 to 1.1 g/t gold mineralization. Zones of higher grade, when encountered, will be a bonus.
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Longitudinal section showing flat-lying nature of zone intersected at northern end of La Nariz. Zone is roughly controlled by layers of intraformational breccia, but will likely thicken along zones of faulting. Silicified areas, including jasperoid, would be anticipated at both the eastern and western edges of this section, near the contact with overlying sandstone. If contemporary Nevada-type models apply, the zones of faulting could host high grade.
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La Nariz air photo detail. Core of limestone (grey) passes left, right and down into younger sandstone & shale (browns), Note the zones of faulting, jointing and collapse. Pond in centre is the Sinkhole. Grid lines are 200 m squares.
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La Nariz (and Cerro Oeste) drill plan with surface chip-sampling results. Zone outcrops in cliff faces N-NE of 14/15 set-up and E and SE of 13. Grid lines are 50-metre squares.
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Two structures, the north-dipping BWC fault (and associated dyke) and a steep NNW normal fault separate the La Nariz panel of geology from the Cerro Oeste – Greg panel. Here, a four to five metre-thick mudstone sits between overlying sandstone and underlying limestone. The mudstone has been both surface-sampled and trenched intermittently through a 700-metre strike length and is anomalous in gold throughout. Where the mudstone and underlying limestone units are near E and NE trending faults, the rocks are cut by near-vertical zones of carbonaceous breccia that is strongly mineralized (i.e. 6.0 m grading 6.34 g/t gold) that is enveloped by softer, slightly lower grade sheared mudstone and limestone breccias. Of four earlier holes (T05-8 to 11), half stopped short of testing the steep mineralized structure, and core recovery was very poor in the other two. Following are some surface sample results on these targets:
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Target
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Sample length
(metres)
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Gold
(g/t)
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Notes
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Target
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Sample length
(metres)
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Gold
(g/t)
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Notes
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Greg
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6.0
13.5
10.0
8.0
14.0
6.0
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5.23
5.11
6.31
2.56
1.96
5.03
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Five outcrops in a 100 metre-long area of siliceous mudstone bx.
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Cerro Oeste
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6.0
8.0
21.7
14.5
8.0
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6.34
2.56
1.00
1.47
1.10
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Trenches in 150 by 20 m strip of siliceous mudstone bx.
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The panel of geology that hosts the Cerro Oeste – Greg targets is separated from the Encantada – Saturno panel by a NE ramp fault. Saturno is the site of numerous small pits and tunnels developed in the 1960’s and 70’s on zones of oxide zinc-silver mineralization found at the intersection of dolomitic limestone breccia and east-directed reverse faults. The Encantada is a 1600 metre-long target defined by high contrast soil anomalies, outcropping hydrothermal breccia, and jasperoid dykes and manto-like carbonate replacement bodies. The zone is coincident with the limestone-sandstone contact, and may be up to 80 metres thick. Evidence of limestone de-carbonitization and solution collapse is common.
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Encantada - view looking south, Toyota 4x4 for scale. Limestone terrain dips 70o to the west, Area of initial seven holes at head of valley, 2 km away.
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Some Encantada surface results include:
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Sample length
(metres)
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Gold
(g/t)
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Notes
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14
25
25
22
6
31
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4.15
13.31
7.87
7.79
5.01
3.95
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Anomaly and mineralized outcrops span over 1600 m length.
Samples are from jasperoid outcrops.
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Encantada Sur – drill plan and cross section.
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Initial drilling at Encantada (7 holes at the southernmost end) was somewhat disappointing. The zone of closely-spaced jasperoid veining seen on surface in this segment was not found in core, and the high grade mantos found outcropping up the hill do not dip west towards the drill pads. Instead, an east-dipping fault occurs along the footwall contact of these mantos (probably the fault is mineralized – i.e. IT is the target), and east-directed holes will stay deep beneath the structure.
Recently a trench was dug adjacent to the mineralized interval in hole T05-1 (5.95 m grading 3.03 g/t). The mineralized manto was traced over a distance of 20 metres and is up to 6 metres thick (6.0 m grading 5.01 g/t). The same manto is thought to be offset beneath the trench, then is re-encountered 25 metres below surface by hole T05-5 (5.0 metres grading 2.71 g/t gold), and is open to depth and laterally.
Exploration Potential: Based on results thus far, Tucumachay has good potential to host several gold deposits. La Nariz is seen to offer superior tonnage possibilities, and is high priority. Deep high-grade potential may exist, but as a junior explorer we are stuck with the task of chasing mineralization “from the top, down.” It is hard for us to drill deep glory holes early in the project’s history. Cerro Oeste, Greg and Encantada offer better grades, however jasperoid targets are notoriously fickle to drill, and should be approached either with caution or a prohibitively expensive saturation-style drill campaign. That being said, field crews feel sufficiently confident that renewed drilling is planned on these targets.
Exploration Models: Tucumachay challenges conventional Andean gold geology concepts. This is not a skarn deposit like Antamina, nor is it a high sulphidation deposit like Yanacocha or low sulphidation like Round Mountain. It is not a mid-sulphidation system like at Colquijirca – Cerro de Pasco or simply a distal carbonate-replacement deposit like Jeronimo (though both need to be kept in mind). The geology, alteration and geochemistry strongly suggest a Carlin-type model should be employed, and that Gitennes should look to Nevada for guidance. Key aspects reminiscent of “Carlin” geology are the jasperoids, the As-Hg-Tl geochemical association, decarbonatization phenomena, micron-gold, arsenian pyrite and hydrothermal carbonaceous alteration. Differences are, number one, this isn’t Nevada, and two, it is a relatively clean limestone-host sequence, not the trashy mixed calcareous sequence typical of Lower Plate geology.
At Tucumachay exploration is done under a Category C Permit (the highest pre-production permit available), community agreements are in place, and the Company is working to maintain its social license in the region through employment, local land use and water use agreements, community involvement and environmental stewardship set by example.
Exploration work at Tucumachay can proceed all year long. The property is an eight hour drive from Lima. Road access is good, there are numerous sources of water, and there is no “field season”. The area is an alpine desert, with a metre of precipitation annually. Snow flurries may occur in the late afternoon as the sun sets and air temperatures fall. Any snow has usually sublimated by early morning.
Option Agreement:
The Tucumachay Project is held under option from Inmet Mining Corporation. Gitennes has met its obliged exploration expenditures under the agreement, and may now earn its 100% interest in the project by incurring additional expenditures of (approximately) US$ 800,000 before December 31, 2008. Once Gitennes has completed 12,000 metres of drilling Inmet may earn-back a 60% interest by spending three times Gitennes’ total project-related expenses to that point. If Inmet elects to not earn-back then it will be left with a 0.75 to 1.25 percent net smelter returns