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Introduction
The Rocky Brook property consists of 258 mineral claims (6,450 hectares) and is located in the Deer Lake Basin of Western Newfoundland. JNR optioned Rocky Brook from Altius Minerals Corporation (Altius) and has earned an undivided 70% interest in the property.
Previous Work
Exploration work by Westfield Minerals in the late 1970's and early 1980's identified three significant fields of altered and mineralized sandstone boulders that reported values ranging from 1% to more than 10% uranium oxide (U3O8) as well as very high grade silver contents.
The mineralized boulder areas, known as Birchy Hill Brook, Wigwam Brook and Goose, occur within relatively thin tills above the Carboniferous Deer Lake Basin in western Newfoundland and strongly resemble the underlying Humber Falls Formation. Westfield's previous work assumed that the source of the boulders lay to the southwest, and tested that direction unsuccessfully with 100 short diamond holes. Recent quaternary studies and exploration work suggests that the glacial ice movement was in a south-southwest direction, and hence the source of the boulders has been re-interpreted to lie to the northeast.
The Rocky Brook Property was under a joint venture agreement between Altius and Cameco Corporation until mid-July 2004. Over a 2-year period, Altius and Cameco completed a digital compilation, flew a detailed airborne horizontal gradiometer survey, conducted lithogeochemistry, prospecting, grid geophysics and a 96-hole sonic drilling program with borehole radiometrics and extensive till and heavy mineral analyses. This program identified a 1.5 km-long uranium till anomaly that coincides with and extends northward or "up-ice" of the Birchy Hill Brook mineralized boulder field. No previous drilling has tested this area.
2005 - 2006 Exploration Programs
In 2005, JNR-Altius drilled forty holes in the Wigwam Brook area. Significant radiometric and geochemical anomalies were intersected in glacial tills and drill core in several holes. The best results occur in an area approximately 350 metres up-ice of the boulder cluster. Drill hole RB-05-027 returned an assay of 0.014% U3O8 over 0.7 metres, with associated copper, cobalt and silver enrichment. A number of other holes in the vicinity also contained significant geochemical enrichment. Systematic sandstone samples from RB-05-022 returned up to 54.7 ppm uranium, 1.5 ppm silver and 730 ppm copper. Samples from RB-05-029 returned up to 14.9 ppm uranium, 6.7 ppm silver and 380 ppm copper. Of particular interest is that strong hematite and clay alteration is associated with the anomalous intervals.
Thirty-eight holes were drilled in the Birchy Hill Brook area. They identified a major radiometric anomaly in glacial till, which forms a ribbon-shaped horizon 1-metre thick, 100-200 metres wide and a minimum of 800 metres long. This anomaly can be traced northward from the boulder cluster at surface, eventually plunging downward through the 10-metre thick till profile toward a prominent magnetic anomaly, which may represent the bedrock source. The most significant geochemical enrichment in drill core occurs in RB-05-078, located 250 metres (up-ice) of the boulder cluster near a geophysically interpreted major structure. This hole returned up to 17.7 ppm uranium accompanied by anomalous vanadium, tellurium and silver.
In 2006, 65 holes were drilled totalling 2,881 metres. Highlights include the best mineralization intersected to date on the property, in two holes located approximately 50 metres east of the Wigwam Brook boulder field and within a broad 700-metre long drill-defined radioactive bedrock anomaly. The anomalous radioactivity appears to be stratigraphically controlled and occurs within a hematized sandstone unit bounded by interpreted reverse faults. RB-06-117 intersected a grade equivalent (downhole-probe result) of 0.54% U3O8 over 0.10 metre within a 0.4-metre interval that assayed 0.075% U3O8 and 4.4 ppm silver. Fifty metres to the south, RB-06-127 intersected a 0.5-metre interval of 0.080% U3O8, 1030 ppm copper and 2.2 ppm silver. Both intersections occur at shallow depths just below the overburden/bedrock interface. Other significant mineralization intersected in the Wigwam Brook area includes a 0.5-metre interval in RB-06-126, located 10 metres east of hole RB-06-117, that assayed 0.021% U3O8, 900 ppm copper and 5.2 ppm silver.
Anomalous radioactivity was encountered in several holes drilled immediately northwest of the Birchy Hill Brook boulder anomaly. The radioactive zones occurred immediately below the overburden/bedrock interface and are associated with hematized sandstone and mudstone units. The drill holes tested a prominent magnetic lineament, interpreted cross structures and a colour-defined redox boundary.
An airborne radiometric, magnetic and electromagnetic survey completed in July 2006 identified several prominent magnetic and radiometric anomalies in the areas of the historic Wigwam Brook, Birchy Hill Brook and Goose prospects, as well as a number of anomalous zones elsewhere. The radiometric survey proved to be the most effective in locating and extending a number of radioactive boulder trains.
2007 Exploration Program
Drilling to date, including the 82-hole (2,486 metres) program in 2007, has identified two areas of low level anomalous radioactivity at or near the overburden-bedrock interface. Both areas lie proximal to the high-grade boulder clusters. Several geochemically-enriched fault structures and/or redox alteration fronts thought to possibly control the high-grade uranium-silver mineralization have also been defined. Structural interpretation and the development of a 3D model utilizing all downhole data is in progress and expected to be completed prior to the next drilling campaign.
Anomalous uranium, copper and silver values were obtained in drill core from several of the 2007 drill holes at Rocky Brook, the most significant of which are narrow intervals in four holes drilled in the vicinity of the Birchy Hills and Wigwam Brook boulder fields. RB-07-144 and RB-07-152, drilled up ice of the Birchy Hill showings, intersected 0.5-metre intervals returning 45.2 ppm U, 202 ppm Cu, 4.9 ppm Ag and 15.3 ppm U, 302 ppm Cu and 6.9 ppm Ag, respectively. RB-07-192 and RB-07-196, drilled in the vicinity of the Wigwam Brook mineralized boulder field, intersected 0.5-metre intervals of 49.9 ppm U, 5.2 ppm Ag and 62.7 ppm U, 310 ppm Cu, respectively.
2008 Exploration Program
A water geochemical survey was carried out in the summer of 2008 to assist in delineating additional drill targets in the primarily bog-covered terrain of the Deer Lake Basin (see news release dated August 29, 2008). The survey was conducted over the most prospective portions of the Rocky Brook property and a total of 1,025 samples were collected and analyzed for trace elements by ICP-MS. Evaluation of the results of that survey is now complete. Uranium and associated trace element anomalies were detected up-ice of the Birchy Hill Brook, Wigwam, and Goose boulder fields as were seven additional target areas on the property. Associated elements within the anomalies include arsenic, barium, bromine, copper, molybdenum, lead and, selenium. Most of the anomalies define linear trends, which suggest an underlying structural control marginal to areas exhibiting a carbonate signature.
2009 Winter Program
A 22.7 km induced polarization (IP) survey was carried out in the winter of 2009. The IP survey was initiated to better define the structural controls suggested by the geochemical survey. The initial results were impressive enough that the survey was extended to provide detailed results in select areas. Preliminary results indicate the presence of several significant structural features coincident with the geochemical trends, which also appear to parallel the azimuth of the drill holes completed to date. This suggests that previous drilling did not test these highly prospective features in the optimum localities.
2009 Summer Program
Incorporation of the new IP and geochemical data into the current 3D model is in progress. This work will be used to direct the planned 2,000-metre diamond drilling program that will be initiated later this summer.
JNR's Vice-President Exploration, David L. Billard, PGeo, is the Qualified Person for the Rocky Brook Property.
Technical Presentations
 JNR's Uranium Exploration in Newfoundland (7.4 Mb)
JNR's Use of GOCAD in Uranium Exploration (8.4 Mb)
Quality Assurance & Quality Control Program
Photo Gallery
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