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Trebol is an epithermal vein system and a relatively new Radius project discovered during stream sediment and reconnaissance rock sampling within the Region Autonoma Atlantico Norte (RAAN) in northeastern Nicaragua. Prospecting work during 2006 found notable amounts of free, visible gold in stream sediment and quartz float in two areas. Follow-up investigations discovered epithermal gold mineralization associated with a series of low-lying ridges - they are of typical low-sulphidation affinity and comprise banded quartz breccias and stockworks with visible gold noted at some locations. Due to the thick, tropical vegetation cover, outcrop is very limited at Trebol, and the hand excavation of trenches often several metres deep is necessary to reveal bedrock at depth, and although this can be an arduous job, it is one of the ways the Company is able to provide the local communities with work. Trenches of varying lengths were excavated over a strike length of approximately 6km, although the limits of the mineralized system are still unknown. Below you'll find a chart of the selected trench sample highlights.
Trench Number |
Sampled Interval |
Weighted Average Au g/t |
TRSD-01* |
13.5 |
0.24 |
TRSD-02* |
10.4 |
1.34 |
TRSD-03* |
34.0 |
1.0 |
TRSD-04* |
35.25 |
4.91 |
includes |
8.35 |
17.6 |
TRSD-05* |
11.65 |
2.7 |
TRSD-06* |
10.0 |
0.93 |
TRSD-07* |
13.4 |
0.5 |
TRSD-08* |
12.65 |
0.75 |
TRSD-09* |
19.43 |
0.37 |
TRSD-10* |
9.0 |
0.37 |
TRSD-11* |
11.8 |
0.38 |
TRSD-12* |
11.0 |
0.29 |
TRSD-13* |
6.0 |
1.73 |
TRSD-14** |
22.0 |
0.57 |
includes |
6.0 |
1.0 |
TRSD-15** |
33.8 |
3.4 |
including |
15.0 |
6.1 |
TRSD-16** |
13.0 |
0.19 |
TRSD-17** |
20.0 |
0.87 |
*Release dated Oct 16, 2007 and April 7, 2008
**Refer to Press Release dated April 7, 2008
Drilling
The results of the trenching were encouraging and a preliminary drill program was recently completed and comprised a total of 9 holes totaling 963m. The holes were designed to test the sub-surface continuity of the gold grades observed in selected trenches in the southwest of the property, and to give geological and structural information on the geometry and controls on mineralization.
Significant intercepts are given below;
Drillhole Number |
From (m) |
To (m) |
Interval (m) |
Assay Au g/t |
Hole Depth (m) |
TRDH-08-01 |
12.19 |
35.3 |
23.11* |
1.51 |
61.87 |
TRDH-08-02 |
28.95
35.4
36.57 |
35.4
36.57
50.29 |
6.45**
1.17
13.72 |
0.49
No recovery
0.71 |
123.44 |
TRDH-08-03 |
59.44
112.77 |
84.82
120.39 |
25.38***
7.62 |
0.44
1.37 |
138.68 |
TRDH-08-04
inc. |
3.3
5.25 |
24.38
15.5 |
21.08
10.25 |
1.44
2.55 |
45.41 |
TRDH-08-05
inc |
6.09
6.09 |
59.5
25.9 |
53.41
19.81 |
1.35
2.89 |
77.72
|
TRDH-08-06 |
2.15 |
7.97 |
5.82 |
1.02 |
125.27
|
TRDH-08-07 |
No Significant Assays |
204.82 |
TRDH-08-08
incl. |
57.6
68.08 |
108.1
69.0 |
50.5
0.92 |
0.61
11.21 |
120.39 |
TRDH-08-09 |
No Significant Assays |
65.53 |
* Core recovery averaged 72% over the interval
** Core recovery averaged 70% over the interval
*** Core recovery averaged 77% over the interval
Mineralization drilled in all holes is associated with broad zones of banded quartz -(adularia) veins, stockworks and silicified breccias, typical of low-sulphidation epithermal systems, which correspond to the down-dip continuation of the mineralized zones sampled in the surface trenches (see Trebol gallery for core photos).
Textures generally show early multiple-stage brecciation, silicification and fracturing/annealing events which precede a later cockade textured, drusy, coarse-grained quartz mineralization.
Host rock to mineralization is a tuffaceous sandstone/lithic tuff unit associated with strong sericite-clay alteration and pyritization which forms part of a transition zone to a footwall mafic volcanic unit of basaltic composition. The broad, shallow-to-moderately dipping tabular zones of alteration suggest a strong replacement/lithological control on mineralization and is a different mineralization style to that normally seen in Nicaragua.
All holes with the exception of TRDH-08-07 were drilled at 45 degrees and perpendicular to the perceived dip of the zones, and therefore intervals represent approximate true widths
The thickest gold intercepts were seen in holes TRDH-08-05 and TRDH-08-08 which were drilled along a section (see drill sections) and the zones attained >50m true thickness (TRDH-08-05 -- 53.4m @ 1.35 g/t from 6m depth). Comparison of the gold grades sampled in surface trenches with those from the drillholes show that grades weaken progressively with depth. This suggests that an enrichment effect in gold has taken place in the near surface saprolite due to weathering processes (called supergene enrichment, and common in tropical environments such as Nicaragua). Although this indicates that the probability of finding an economic deposit at much deeper levels is limited, potential could exist for a series of small, surface/near surface deposits that could be pitted with little/no stripping ratio.
Soil geochemistry and follow-up trenching has identified several additional zones of similar style mineralization associated with low-lying ridges located north, south and up to several kilometres laterally from the drilled ridge. Further trenching and detailed drilling will be required to evaluate the resource potential of the outcropping/near surface gold mineralization within the area drilled to date and test the potential in the adjacent areas. No metallurgical tests have been undertaken by the company to date.
Data from the exploration and drilling work will be compiled and a decision taken regarding future exploration on the property. It is likely that a joint venture partner will be sought to advance the property.
Detailed Description of Drillholes
TRDH-08-01 and two step-out holes TRDH-08-02 & 03 were drilled along a section at -45 degrees inclination on the west slope of the silicified ridge to test the mineralized zone underneath Trench 15 (33.8m at 3.4 g/t Au - refer to press release dated April 7, 2008). Drilling confirmed a tabular zone of silicification some 20 -- 25m thick that forms the dip slope of the ridge and continues to at least 140m down dip. The higher gold grades seen in TRDH-08-01 from 12.19m to 33.3m ranged from 0.21 to 3.34 g/t Au and intersected the zone some 40m down dip of Trench 15.
The weaker gold grades observed in TRDH-08-02 & 03 which intercepted the mineralized zone observed in TRDH-08-01 at progressively deeper levels, suggests that supergene processes are likely accountable for the higher grades seen in Trench 15 and TRDH-08-01, as similar pervasive epithermal veining and stockworks are observed in all three holes. The deeper intercept of 1.37 g/t Au over 7.62m in TRDH-08-03 from 112.77m to 120.39m is related to a shear zone in mafic volcanics.
Hole TRDH-08-04 was collared approximately 1km to the northeast of section TRDH-08-01, 02, 03 and drilled at an inclination of -45 degrees to the southeast underneath the ridge in the vicinity of Trench 4 (35.25m at 4.9 g/t Au- refer to press release dated October 16, 2007), located some 90m away. A zone of strong silicification and veining was intersected within the first 25m before passing into altered mafic volcanics. The interval assayed 1.44 g/t Au over 21.08m from 3.3m to 24.38m depth, with a higher grade intercept of 2.55 g/t Au over 10.25m from 5.25 to 15.5m. Two initial holes drilled further up dip that were discarded for assay purposes due to unacceptable recoveries, suggest a gently dipping attitude to the mineralized zone.
Hole TRDH-08-05 was drilled some 150m north of TRDH-08-01 to test the depth continuity of mineralization seen in Trench 2 (10.4m at 1.3 g/t Au - refer to press release dated May 29, 2007) and the recently sampled Trench 21 which assayed 6.1g/t Au over 17.1m (previously unreported). From 6.09 to 59.5m the hole averaged 1.36 g/t Au over 53.4m. Highest grades are associated with massive banded quartz veins and breccias with 1-5 percent pyrite and black manganese oxides, with assays up to 17.8 g/t Au (18.75m -- 19.81m corresponding to part of the vein zone sampled in Trench 21). Weaker stockworks and silicified zones form zones of lower grade mineralization within the tuff and mafic volcanic sequence further down the hole. Further step-out drilling is required to determine grade continuity at depth.
TRDH-08-06 was drilled at -45 degrees to the southeast to test underneath the silicified ridge in the vicinity of Trench 17, where surface trench sampling gave gold grades ranging from 0.47 g/t to 2.07 g/t Au (averaged 0.87 g/t Au over 20m). Crustiform and banded epithermal quartz with some amethyst was intersected in the first few meters of the hole, and assayed 1.02 g/t Au over 5.82m, and gave way to a sequence of basaltic tuffs, breccias and flows, showing that the silicified zone forms the western dip slope of the ridge and has a gentle to moderately dipping tabular geometry.
TRDH-08-07 was drilled from the same location as TRDH-08-03 at an azimuth of 280 degrees and an inclination of 70 degrees, and was designed to test the extension of the broad banded quartz and stockworks intercepted in TRDH-08-03 for depth continuation and deeper higher grade feeder mineralization (refer to press release dated August 7th, 2008). From 185.8m to 205m (end of hole) the mineralized zone was intersected but showed weaker stockwork development and gold values ranging from 0.06 to 0.6 g/t Au.
TRDH-08-08 was drilled some 85m west-north-west along section of TRDH-08-05 to test the down dip extension of the near surface mineralization intersected in the latter (1.36 g/t Au over 53.41m). Similar quartz-adularia banded vein and stockworks were intersected from 57m to 108m, however grades were generally weaker and averaged 0.61 g/t Au over the interval.
TRDH-08-09 was drilled at the base of the ridge some 65m northwest and along section of TRDH-08-04, to test the down dip extension of the near surface mineralization in this hole (1.44 g/t Au over 21.08m). The remnants of the silicified zone was drilled within the first few meters and assayed <1 g/t Au, which then passed into an altered sequence of tuffaceous mafic volcanic flows and breccias, with only anomalous values in gold (generally <0.5 g/t Au), indicating that the silicified zone is eroded further to the west.
Click Here to View Trebol Photo Gallery
Maps
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