Location
The Sixty Mile Property consists of 701 claims, of which 620 claims are owned outright and the balance are under option from third parties. The Property is a large land position covering portions of the headwaters and drainage areas of the prolific Sixty Mile Placer Gold District in the Yukon Territory.
The property is located approximately 75 km due west of Dawson, adjacent to the Yukon-Alaska border. Access to the claims is by the posted 15-km long Sixty Mile road, from the Top of the World Highway.
Ownership
100% Rackla- Core Asset
Geology and History
The Sixty Mile property, which was never glaciated, covers 6 creeks or rivers with active placer gold mining. Historical placer gold production from the Sixty Mile Placer Gold District is reported to exceed 500,000 oz of placer gold. Most of the property is underlain by foliated Paleozoic metasedimentary rocks, minor Jurassic felsic intrusives and nonfoliated latest Cretaceous age Carmacks Group intermediate volcanics and felsic to intermediate intrusives.
Radius Gold Inc. indentified two separate targets on the property, the Thrust Fault Zone, an orogenic gold target hosted by foliated Paleozoic metasedimentary rocks and the Graben Fault Zone, latest Cretaceous aged porphyry -- epithermal target hosted by Carmacks volcanics and granitoids. In 2010 and 2011 Radius Gold Inc. drilled a total of 27 diamond drill holes (6881.3 m) plus carried out auger drilling (349 holes), rotary air blast (RAB) drilling (84 holes totaling 3326.56 m), mechanized trenching (13 trenches, 1134 linear meters), geological mapping, geochemical sampling, and an airborne aeromagnetic and radiometric survey.
The Thrust Fault Zone
The Mineral Deposit Research Unit of the University of British Columbia concluded that the bedrock source for most of the placer gold is from orogenic type quartz veins. Anomalous gold values from trenches and diamond drill holes on the Thrust Fault Zone indicate it is one of the sources. The most significant drill hole to date is DDH11-18; 507 ppb Au over 105.7m including 1.57 g/t Au over 24.07 m. The regional geology, geochemical signature and structural setting points to an orogenic gold source similar to Kinross Gold Corporation's White Gold deposit (
http://www.kinross.com/operations/dp-white-gold,-yukon.aspx).
Placer gold was first discovered in the Sixty Mile district in 1892 when C. Miller staked claims on what was to become known as Miller Creek. Placer gold mining has continued in the district to the present day. Various companies and several well know Yukon prospectors explored portions of the property from the 1970's onward for bedrock sources of the placer gold. Companies included; Norada, Homestake Mining, Esso Minerals, Teck Corporation and Madrona Mining Ltd. although generally only surface work was carried out. In 1989 Layfield Resources diamond drilled seven holes (410.7 m) on what is now part of the Thrust Fault Zone (Layfield Grid).
Kennecott Canada Inc. targeted the area in their Yukon-Alaska intrusion-related bulk tonnage gold program in the late 1990s. They conducted a property-wide reconnaissance soil and stream geochemical sampling program, geological mapping, and a 640 line-km helicopter magnetic and radiometric survey followed by mechanized trenching. Kennecott noted that the mineralization is very similar in style to that found in other metasediment-hosted granite-related porphyry gold systems within the Tintina Gold Belt.
The Kennecott soil sampling defined several arsenic/gold anomalies, including a coherent 1.5 km x 2 km-diameter, gold-arsenic soil anomaly, now the Kennecott Grid on the south side of lower Miller Creek (part of the Thrust Fault Zone). Excavator trenching at the readily accessible southern edge of this anomaly revealed easterly striking sheeted mesothermal quartz veins. Rock chip samples from returned 1.6 g/t gold over a 13 meter interval in Trench 99-6. After a ten year hiatus Radius Gold Inc. resumed exploration in 2010.
Radius drilled eight diamond drill holes (2368.9 m) on the Thrust Fault Zone in 2010 and 2011 plus carried out RAB drilling, auger drilling, mechanized trenching and induced polarization -- resistivity (IP) surveys over portions of the Thrust Fault Zone. This work
identified orogenic gold mineralization within a package of northeast trending brittle siliclastic metasedimentary rocks cut by thrust faults. This area is likely one of the sources for the extensive placer gold deposits that has been mined from the creeks that cut this unit. The host units are extensive with multiple beds of quartzite hosting cross cutting, gold bearing veins.
Drill hole DDH11-15 targeted mineralization down dip of mineralization intersected in the upper portions of 2010 drill holes DDH10-1, 2 and 3. Sample results from hole 15 are similar to those received in 2010 including a 4.0 meter section (from 234.00 -- 238.00 m) that graded 1023 ppb gold. Drill hole DDH11-18 targeted brittle quartz rich unit intersected in DDH10-3 that returned 160 ppb gold over 79.27 m. The drilling direction of DDH11-18 was close to right angles to that of DDH10-03 as the purpose of hole 18 was to intersect the quartz veins at a high angle compared to the low angles observed in drill core in 2010. Best results from DDH11-18 include 1.5 g/t Au over 24.07 meters (from 141.93 m -- 166.00 m), where visible gold in quartz veins was observed, within a broader 105.30 m interval that graded 507 ppb (from 88.00 -- 193.30 m).
Drill hole DDH11-19, located approximately 950 m northwest of DDH11-15, 18 and DDH10-1, 2 & 3, targeted resistivity and induced polarization (IP) anomalies. The best result was 1837 ppb gold over 4.10 m (from 224.50 m -- 228.60 m) from a quartz veined quartz rich schist unit.
Drill hole DDH11-20 targeted the Thrust Fault Zone at the Layfield Grid and like DDH11-19 located approximately 2.1 km to the southwest, targeted resistivity and IP anomalies. Best values included three narrow (0.97 m to 2.67 m) intervals of >1 g/t Au from a fault zone and sericite altered and silicified schist.
Thrust Fault Zone; Significant Diamond Drilling Results for Gold
| Hole ID |
From (m) |
To (m) |
Length (m)* |
Au ppb |
| DDH10-01 |
10.02 |
32 |
21.98 |
346 |
| including |
10.67 |
17.8 |
7.13 |
656 |
| DDH10-02 |
35.65 |
76.43 |
40.78 |
414 |
| including |
35.65 |
43.28 |
7.63 |
1065 |
| DDH10-02 |
223.6 |
249.94 |
26.34 |
342 |
| including |
241.4 |
243 |
1.6 |
2907 |
| DDH10-03 |
35.05 |
45.72 |
10.67 |
461 |
| DDH10-03 |
85.34 |
92.96 |
7.62 |
269 |
| DDH10-03 |
243.82 |
323.09 |
79.27 |
160 |
| including |
243.82 |
251.46 |
7.64 |
544 |
| DDH10-04 |
193.55 |
201.19 |
7.64 |
325 |
| DDH11-15 |
193 |
196.5 |
3.5 |
1504 |
| DDH11-15 |
233.17 |
251.05 |
17.88 |
435 |
| including |
234 |
238 |
4 |
1023 |
| DDH11-18 |
88 |
193.3 |
105.3 |
507 |
| including |
141.93 |
166 |
24.07 |
1569 |
| DDH11-19 |
224.5 |
228.6 |
4.1 |
1837 |
| DDH11-20 |
182.98 |
185.65 |
2.67 |
1061 |
| DDH11-20 |
201.78 |
202.75 |
0.97 |
1794 |
| DDH11-20 |
272 |
273.03 |
1.03 |
1395 |
*True widths for the above drill core intersections have yet to be determined.
In April 2012, Rackla Metals received a report from Aurora Geosciences Ltd. detailing the results of the geophysics (IP and EM) carried out over the area of the Thrust Fault Zone that was drill tested by Radius in 2011. The report concluded that the best drilling results obtained to date, 1.57 g/t Au over 24.07 m (141.93 m -- 166.00 m) in DDH11-18, is found at the margin of a chargeable zone which is offset from a conductive zone. It is thought that this margin represents a contact or thrust plane which acted as a fluid contact. The report recommended that this contact be tested with additional drill holes along strike to the southeast. Samples from drill holes DDH11-19 and DDH11-20 contained significant Au and arsenic values and both holes were also drilled at the margins of chargeability / conductivity highs. Additional geophysics and drilling is recommended to test this kilometre scale target model.
The Graben Fault Zone
In 2010 Radius Gold Inc. recognized the epithermal precious metal potential in the Sixty Mile River valley. During diamond drilling in 2011 porphyry copper -- molybdenum style mineralization was intersected. This combined target, now named the Graben Fault Zone, is structurally controlled by the north easterly trending Sixtymile -- Pika fault bounding fault. This major sinistral trans tensional fault of latest Cretaceous age is thought to extend for approximately 130 km. The valley and some adjacent hilltops are comprised of latest Cretaceous age (approximately 67 -- 70 Ma) Carmacks andesitic volcanics with the volcanics in the valley being preserved in a down dropped half graben. The Carmacks volcanics are part of a widespread magmatic event that in the Sixtymile district, along with alteration and mineralization over an approximate eight kilometer strike length, is controlled by extension in the Sixtymile -- Pika fault corridor.
Previous workers, primarily placer miners, from the 1920's onward recognized the mineral potential of the altered, pyritized, Carmacks volcanics. In 1988 Klondike Gold Mining Corporation optioned the Per occurrence, located in the Sixtymile River valley (part of the Graben Fault Zone), from prospector Erwin Kreft and drilled 7 holes (765 m) and intersected 8.76 g/t Au over 10.5 m in DDH D4/88-02. In spite of this success no additional drilling took place and little exploration work of any type was carried out until 2010 when Radius commenced work.
In 2010, Radius drilled two holes at the Toni occurrence (part of the Graben Fault Zone), testing the volcanic rocks proximal to the Sixtymile fault zone where soil samples containing 1+ g/t gold in soil were collected. Both holes returned highly anomalous gold values over plus-50-metre intervals with narrower intervals of potentially ore-grade material (see Radius's news release dated Nov. 16, 2010).
In 2011 work grid auger drilling (335 holes totaling 2953 m), ground geophysical surveys and diamond drilling tested for epithermal mineralization over the Graben Fault Zone. Sixteen diamond drill holes (4047.8 m) targeted the Graben Fault Zone. The initial 2011 drill holes (DDH11-01, 02, 03 and 06) targeted down dip and along strike of drill hole DDH10-06 & 7 at the Toni occurrence, and while these holes returned erratic anomalous gold values with some narrow >1g/t Au intervals, the drilling did not identify potential for a bulk-tonnage gold target at the Toni occurrence.
The Carmacks volcanics are strongly altered over an 8km long strike length, and largely buried beneath placer gold-bearing river gravels, presenting a significant challenge for drill targeting. Results from the grid auger drilling returned scattered anomalous values for gold and pathfinder elements along with a coherent copper in rock anomaly (207 ppm -- 1625 ppm Cu) over four lines spaced 400 m apart. Clays in the bedrock sample were then identified by short wave infrared spectroscopy, and a Controlled Source Audio Frequency Magneto-telluric (CSAMT) geophysical survey was also used to identify resistivity highs and lows for drill targeting.
Holes DDH11-08 and 09 tested the historic Per occurrence (see Radius's news release dated June 6, 2011) which lies within a zone of illite alteration that extends towards the east where holes DDH11-10 and 14 tested fault structures. DDH11-08 intersected strongly bleached and sericite altered Carmacks Group andesite crosscut by narrow dolomite pyrite veins that contained 19.0 g/t Au from 193.5 m to 194.5 m.
Drill hole DDH11-10 intersected 132 g/t Au over 1.5m. This hole was drilled 1.4km east northeast of hole DDH11-08. The interval consisted of bleached, hematized and sericite altered quartz feldspar biotite schist cross cut by minor quartz/pyrite veins. The large scale of the alteration system which can be traced over an 8km strike length, required that the 2011 drilling was very widely spaced in order to drill test several targets. The high grade intercepts in holes DDH11-08 and 10 are potentially related to an alteration zone that can be traced for a distance of 2 km, requiring further follow up work. DDH11-14, collared approximately 400 m east of DDH11-10, intersected a 1.0 m interval of propylitic altered andesite with limonitic zones that graded 5172 ppb gold.
Drill holes DDH11-04, 05, 07, 11, 12 and 13 tested potential silica bodies outlined by the geophysical program. Several of the holes intersected broad zones of anomalous base metal values. For example, holes DDH11-03, 04 and 05 intersected a high level porphyritic granitoid with quartz stockwork veining containing chalcopyrite and minor molybdenite, but none of these geophysical anomalies proved to have merit as gold targets. The anomalous copper values in these diamond drill holes confirmed the anomalous results obtained in by auger drilling. DDH11-09, 16 and 17 did not return any significant gold values.
Graben Fault Zone; Significant Diamond Drilling Results for Gold
| Hole ID |
From (m) |
To (m) |
Length (m)* |
Au ppb |
| DDH10-06 |
12.19 |
86.87 |
74.68 |
199 |
| including |
49.84 |
56.39 |
6.55 |
1645 |
| DDH10-07 |
88.39 |
146.67 |
58.28 |
318 |
| including |
120.4 |
127.26 |
6.86 |
646 |
| DDH10-07 |
206.6 |
208.07 |
1.47 |
4458 |
| DDH11-08 |
193.5 |
194.5 |
1 |
19 g/t |
| DDH11-10 |
249 |
250.5 |
1.5 |
132.9 g/t |
| DDH11-14 |
32 |
33 |
1 |
5172 |
*True widths for the above drill core intersections have yet to be determined.
Graben Fault Zone; Significant Diamond Drilling Results for Copper & Molybdenum
| Hole ID |
From (m) |
To (m) |
Length (m)* |
Cu ppm |
Mo ppm |
| DDH11-03 |
25.50 |
320.00 |
294.50 |
380 |
21 |
| DDH11-04 |
319.0 |
403.86 |
84.86 |
356 |
49 |
| DDH11-05 |
8.80 |
262.47 |
271.27 |
542 |
41 |
*True widths for the above drill core intersections have yet to be determined.
The Company received a geophysical report with initial results and conclusions of the CSAMT (Controlled Source Audio Frequency Magnetotelluric) survey that was carried out over the Graben Zone in 2011. Survey results, in addition to indicating complex geology and multiple structural trends, show that the Sixty Mile Fault is not a single structure but rather a broad number of broad shear zones, likely with some vertical movement. The central portion of the CSAMT grid, which roughly corresponds to the approximate area of the copper -- molybdenum rock anomaly partly outlined by the auger drill samples on the same grid, contains a number of unexplained conductive contacts. Additional interpretative work is required to determine how this fits with a porphyry target versus the original target of resistive (silica) gold bearing structures.
Sixtymile Diamond Drill Hole Coordinates, Dips and Azimuths
| Hole Number |
North (NAD 83) |
East (NAD 83) |
Elevation (m) |
Azimuth (deg.) |
Dip (deg.) |
Length (m) |
| RDU_SM_DDH10-01 |
7097093 |
506687 |
1016 |
290 |
-45 |
214.88 |
| RDU_SM_DDH10-02 |
7097073 |
506734 |
1009 |
290 |
-45 |
287.73 |
| RDU_SM_DDH10-03 |
7097167 |
506779 |
1006 |
287 |
-45 |
334.37 |
| RDU_SM_DDH10-04 |
7097148 |
506088 |
1106 |
290 |
-50 |
306.32 |
| RDU_SM_DDH10-05 |
7100455 |
501280 |
1311 |
310 |
-47 |
298.7 |
| RDU_SM_DDH10-06 |
7097850 |
514130 |
735 |
125 |
-45 |
140.21 |
| RDU_SM_DDH10-07 |
7097785 |
514086 |
762 |
40 |
-46 |
240.79 |
| RDU_SM_DDH11-01 |
7097927 |
514065 |
708 |
137 |
-50 |
263.65 |
| RDU_SM_DDH11-02 |
7098003 |
514001 |
655 |
140 |
-50 |
364.99 |
| RDU_SM_DDH11-03 |
7097425 |
513439 |
692 |
140 |
-50 |
320.04 |
| RDU_SM_DDH11-04 |
7097735 |
513184 |
679 |
140 |
-50 |
403.86 |
| RDU_SM_DDH11-05 |
7097433 |
512793 |
686 |
140 |
-50 |
271.27 |
| RDU_SM_DDH11-06 |
7097032 |
513165 |
713 |
140 |
-50 |
192.02 |
| RDU_SM_DDH11-07 |
7096753 |
512055 |
690 |
140 |
-50 |
92.17 |
| RDU_SM_DDH11-08 |
7096251 |
511172 |
696 |
320 |
-50 |
249.94 |
| RDU_SM_DDH11-09 |
7096282 |
511277 |
700 |
320 |
-50 |
207.26 |
| RDU_SM_DDH11-10 |
7096730 |
512732 |
756 |
140 |
-50 |
351.43 |
| RDU_SM_DDH11-11 |
7098253 |
513724 |
664 |
140 |
-50 |
254.51 |
| RDU_SM_DDH11-12 |
7097733 |
514168 |
762.2 |
140 |
-50 |
104.85 |
| RDU_SM_DDH11-13 |
7097729 |
514174 |
761 |
140 |
-50 |
265.41 |
| RDU_SM_DDH11-14 |
7096788 |
513006 |
763 |
320 |
-50 |
330.71 |
| RDU_SM_DDH11-15 |
7097076 |
506727 |
1009 |
110 |
-57 |
289.56 |
| RDU_SM_DDH11-16 |
7098900 |
514839 |
663 |
320 |
-50 |
185.32 |
| RDU_SM_DDH11-17 |
7095678 |
510307 |
701 |
0 |
-50 |
190.44 |
| RDU_SM_DDH11-18 |
7097260 |
506465 |
1027 |
110 |
-62 |
314.55 |
| RDU_SM_DDH11-19 |
7097803 |
505663 |
900 |
126 |
-55 |
312.12 |
| RDU_SM_DDH11-20 |
7099234 |
507494 |
1071 |
116 |
-60 |
309.37 |
