Discovery of Native Silver at Surface at RDN and 2004 Drill Results Northgate Approves 2005 Exploration Program
VANCOUVER, October 20, 2004 – Rimfire Minerals Corporation and Northgate Minerals Corporation are pleased to provide a program update for the Companies’ RDN project. Three target areas were tested with 2,499 metres of drilling in nine holes. Several precious metal bearing intervals were intersected; however these are interpreted as veins and breccias that are unlikely to have economic significance. The most important result of the program was the discovery of native silver at a volcanic/sediment contact in an area (Blind Fault) that has not been previously explored. This discovery, along with discovery of a gold and silver mineralized boulder in a second area (Arctic grid) that has only been superficially explored is very encouraging in such prospective rock types. On the basis of these discoveries, Northgate has committed to funding the 2005 exploration program with the aim of discovering a deposit similar to the Eskay Creek Mine, located 40 km to the south.
Christopher Rockingham, P.Geo. VP Business Development and Exploration for Northgate commented: “ We are encouraged with the progress on the project to date and look forward to following up the new discoveries in 2005. Finding precious metal mineralization in unexplored areas is significant, as is the delineation of stratigraphy correlative to that at the Eskay Creek deposits. Our plan is to explore these new discoveries of precious metal mineralization and to continue to systematically drill test RDN’s favourable stratigraphy” .
The discovery of sediment-hosted silver-rich disseminated and veinlet-controlled mineralization in the Blind Fault area presents a new exploration target for the property. Sulphide mineralization is contained within sedimentary beds and chlorite-altered rhyolite flows positioned below pillow basalt flows. This geological setting, alteration style and sulphide veining of pyrite, chalcopyrite, and galena is consistent with a Volcanogenic Massive Sulphide (VMS) mineralizing system. Five outcrop grab samples at the sediment/volcanic contact collected over a 200 metre length assayed 140, 215, 263, 275, and 363 g/t silver with highly anomalous antimony, mercury, lead, and copper. High silver values are associated with tetrahedrite and native silver. Samples of the rhyolite bodies are also highly anomalous in silver with assays from 10-45 g/t silver.
The second area of interest is the Arctic Grid where previous reconnaissance work had identified felsic stratigraphy including low titanium rhyolites similar in composition to those at the Eskay Creek deposits. This year’s work at the Arctic Grid has shown that the favourable stratigraphy is more extensive than previously thought and the discovery of a mineralized felsic volcanic boulder (3.6 g/t gold, 12.9 g/t silver, 1.2% lead, 4.57% zinc) indicates mineralizing events occurred in the area. Detailed mapping, rock and soil sampling of both the Blind Fault and Arctic Grid areas will be undertaken in 2005 to further delineate and prioritize drill targets for the second phase drill program.
Drill Program Results:
A total of nine holes and 2,499 metres of drilling were completed on the property, testing the Wedge Zone (6 holes), Jungle Anomaly area (1 hole) and Marcasite Gossan
(2 holes).
Wedge Zone
At the Wedge Zone, drilling tested the target contact horizon between strongly altered, sulphide-bearing footwall dacite (felsic) volcanic rocks and hanging wall sedimentary rocks. The strongest mineralization and alteration was intersected in holes RDN04-31, RDN04-32, RDN04-33 and RDN04-35 which were drilled along strike to the north and south of a previous hole, RDN01–17. Hole RDN01-17 intersected 1.5 metres of siliceous, pyritic breccia assaying 3.75 g/t gold at the contact horizon. Significant intersections in the 2004 holes were restricted to the footwall-altered dacite volcanic rocks, occurring in quartz–carbonate veins (holes RDN04-32 and 33), and in a brecciated sulphide shear zone (hole RDN04-31).
Jungle Anomaly
Drilling at the Jungle Anomaly targeted a 100 x 400 metre gold-arsenic soil geochemical anomaly underlain by favourable argillite/siltstone stratigraphy thought to be correlative with the hanging wall sequence at the Eskay Creek deposits. Hole RDN04-37 was drilled to a depth of 336.2 metres entirely within the hanging wall sequence and was stopped before reaching the sediment-felsic volcanic target horizon. RDN04-37 did intersect anomalous gold (58 – 649 ppb) and arsenic (102 – 664 ppm) values in argillite and mafic volcanic rocks near the top of the hole and has likely explained the source of the anomalous soil geochemistry.
Marcasite Gossan
Holes RDN04-38 and –39 were drilled at the Marcasite Gossan. The holes targeted two shallow marine dacite flow domes, which have been altered and cut by stockwork alteration and mineralization, with overlying sedimentary rocks and pillow basalts. Thin beds of semi-massive pyrite that lie in graphitic argillite beds layered between the Upper Marcasite Gossan and basalts, provide a close analogy to the setting of the Eskay Creek deposit. Both holes intersected altered dacite volcanic rocks with elevated antimony and mercury values without significant gold intercepts. |
